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Made available in DSpace on 2022-05-01T05:28:59Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-08-15 Acoustic emission (AE) sensors have been widely used for tool condition monitoring in the grinding process. Recently, the piezoelectric diaphragm (piezoelectric buzzer) was introduced as a low-cost alternative for the same purpose. In this context, the present research work aims to study the efficiency of the piezoelectric diaphragm as a viable substitute to AE sensors in monitoring the dressing of structurally distinct aluminum oxide grinding wheels. Dressing tests were conducted using two industrial wheels, which were subjected to various dressing conditions. The signals generated by the AE and piezoelectric diaphragm sensors were collected simultaneously and subsequently analyzed in both time and frequency domains. The most relevant features related to the dressing were extracted through the following metrics: energy criterion, Pearson correlation coefficient, power spectral density (PSD), fast Fourier transform (FFT), and magnitude-squared coherence (MSC). Correlation greater than 80% was found between the piezoelectric diaphragm and AE sensor signals for determining the actual grinding wheel condition, which indicates the piezoelectric diaphragm as a viable alternative to the commercial AE sensors in dressing operation monitoring. Para Federal Institute (IFPA) Department of Electrical and Mechanical Engineering Sao Paulo State University FAROL Pesquisa Desenvolvimento e Consultoria School of Engineering University Center of Lins (UNILINS) Department of Electrical and Mechanical Engineering Sao Paulo State University

Made available in DSpace on 2022-04-29T08:31:52Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 The grinding of interrupted geometries, such as keyways, holes, lubrication channels and crankshafts, bearings, helical drills, sharpening, and gear hobbing process for pre-toothing, presents technical difficulties such as decrease in surface quality and an increase in costs, when compared to continuous grinding process. This work aims to study further findings about interrupted cylindrical grinding process of AISI 4340 steel, with the application of resinoid aluminum oxide grinding wheel and conventional application of MWF. In a novel and innovative way, this work analyzed the wheel wear cost at 3 different feed rates (0.25, 0.50, and 0.75 mm/min) for continuous workpieces and interrupted workpieces with 2, 6, and 12 grooves. In addition, surface roughness, roundness deviation, grinding power, tangential force, microstructural analysis, diametrical wear, and G ratio were also evaluated. In conclusion to the results obtained, the average values of surface roughness Ra and Rz increased with the severity of the process (feed rate and number of grooves). For feed rates varying from 0.25 to 0.75 mm/min, mean values of 0.51 to 1.10 μm (Ra) and 4.52 to 10.99 μm (Rz) were obtained for the condition with 12 interruptions, indicating an increase in the order of 75 to 114% compared to without interrupted workpiece. The quick wear of the wheel, obtained for an average diametrical wheel wear of 5.79 μm for workpiece with 12 interruptions in 0.75 mm/min, produced higher surface roughness values. Variations of more than 80% in roundness deviation were obtained during grinding at feed rates of 0.75 mm/min due to mechanical shocks during material removal process, being observed in force variations from 50 to 700 N. The cost analysis of grinding wheel wear showed the waste of abrasive material for grinding process with interrupted geometries. For all tests, the tool cost for low feed rate (0.25 mm/min) did not suffer great variations. For feed rates of 0.50 and 0.75 mm/min, the cost of tool wear was higher. The condition with the highest percentage increase in cost was recorded for grinding process with workpiece of 12 grooves and feed rate of 0.75 mm/min, generating an increase of up to 1720% in the tool cost. Converting into monetary values, the wheel cost is of $ 12.62 per 1000-piece batch. Department of Control and Industrial Process Federal Institute of Paraná Jacarezinho Campus Department of Mechanical Engineering São Paulo State University “Júlio de Mesquita Filho” Bauru Campus Department of Mechanical Engineering São Paulo State University “Júlio de Mesquita Filho” Bauru Campus

Made available in DSpace on 2021-06-25T12:23:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-10-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Post Graduate Program of Mechanical Engineering of UFU Post Graduate Program of Mechanical Engineering of UNESP (Bauru campus) ITW Chemical Products Ltda Saint Gobain group One of the peculiarities associated with the grinding process is the large amount of heat generation. Therefore, the cooling lubrication technique plays an important role and must be conducted efficient. Even though the conventional cooling lubrication technique generally outperforms all other techniques, its use is harmful to both the environment and the health of the operator. Thus, techniques that minimize the use of cutting fluids are necessary. Among the various techniques available, minimum quantity of lubrication (MQL) has been widely employed in machining scenarios. However, its use in grinding is questioned because of the poor surface finish generated and thermal damage due to the clogging of the abrasive wheel pores during grinding. To overcome these problems, in this study, an auxiliary cleaning system (CS) of the wheel was used to remove the chips and oil from the clogged wheel surface during grinding, while assessing the CS performance with the aim of making the MQL a technically viable cooling lubrication alternative. Grinding trials were performed on hardened steel under three different cutting conditions using the conventional (flood) cooling lubricant technique and the MQL technique, by applying a biodegradable cutting fluid, with and without the CS. The CS performance was evaluated with regard to the roughness, roundness errors, wheel wear, grinding power, microhardness and residual stresses. Results of both surface roughness and grinding wheel wear were also used to determine empirical equations comparing the traditional MQL technique and the MQL technique with auxiliary cleaning system (MQL + CS). The results showed that MQL assisted with the CS can improve the machined surface integrity, reducing the surface roughness, roundness error and the variation in the microhardness. Furthermore, the MQL + CS condition also presented lower grinding wheel wear. Univ Fed Uberlandia, Sch Mech Engn, Uberlandia, MG, Brazil Inga Univ Ctr UNINGA, Dept Mech Engn, Rod PR-317,6114,Parque Ind 200, BR-87035510 Maringa, Parana, Brazil Sao Paulo State Univ Julio De Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil Univ Minas Gerais, Dept Mech Engn, Av Antonio Carlos 6627, BR-31270901 Belo Horizonte, MG, Brazil Sao Paulo State Univ Julio De Mesquita Filho, Dept Elect Engn Bauru, Bauru Campus, Bauru, SP, Brazil Sao Paulo State Univ Julio De Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil Sao Paulo State Univ Julio De Mesquita Filho, Dept Elect Engn Bauru, Bauru Campus, Bauru, SP, Brazil CAPES: 001

Made available in DSpace on 2020-12-10T20:04:51Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-07-09 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) The final quality of mechanical components has been increasingly desired in the industry. This final quality is directly linked to surface roughness, geometric deviations, and mechanical integrity of components subjected to machining processes. For that, the industry makes use of cutting fluids so that it is possible to achieve such conditions. In the case of grinding, the application of cutting fluid in abundance allows a great reduction in temperature, as well as a better removal of chips from the cutting surface of the wheel. However, the problems generated by the cutting fluid related to environmental and labor liabilities have increasingly led to the development of effective techniques for grinding with minimal amounts of cutting fluid. The difficulties linked to the use of MQL are concentrated in the low rate of heat removal and in the clogging of the cutting surface, varying according to the type of grinding wheel applied. In this sense, the present work proposes comparison during the cylindrical grinding of hardened steel under conventional lubrication conditions, minimum quantity lubricant (MQL), cooled air MQL (MQL + CA), and MQL with wheel cleaning jet (MQL + WCJ), using aluminum oxide (Al2O3) and CBN grinding wheels. The results are presented in terms of surface roughness, roundness error, microhardness, tangential force, diametrical wear of the grinding wheels, and G-ratio. The application of MQL + CA and MQL + WCJ can improve the use of MQL. In terms of roughness, the MQL + WCJ presents values close to the conventional increase of 8.8%. Roundness errors were reduced by up to 36.3% during the application of MQL + CA and MQL + WCJ and up to 10.5% for the tangential force. Thus, these advanced techniques have shown that the conditions are feasible for the application of pure MQL towards an eco-friendly grinding process. Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Dept Elect Engn, Bauru Campus, Bauru, SP, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Dept Elect Engn, Bauru Campus, Bauru, SP, Brazil FAPESP: 2018/22661-2 FAPESP: 2019/24933-2

Made available in DSpace on 2020-12-10T20:03:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-06-30 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) The final quality of mechanical components is directly linked to the efficiency of the machining processes to which it is subjected. In this sense, grinding can provide high standards of surface and geometric quality for mechanical components, since these characteristics are increasingly necessary for the automotive and aerospace sectors. However, the complexity of the mechanical components creates increasing difficulties for grinding. Workpieces with geometric interruptions, as in the case of gears, splined shafts, pistons, and crankshafts generate mechanical impacts and aggravate the thermal gradients during grinding, causing errors of shape, drop in surface quality and reduction in the life of the cutting tool. However, few studies on better conditions for interrupted cut grinding are seen, thus making it difficult to determine ideal grinding conditions. Thus, the present experimental investigation aims to make a comparison between cylindrical grinding of workpieces of hardened AISI 4340 steel with two, six, and twelve geometric interruptions, comparing them with the grinding workpieces without interruptions, applying white aluminum oxide wheels with vitrified and resinoid bonds. Results in terms of surface roughness, roundness deviation, acoustic emission, grinding power, diametrical wheel wear, and micrography are pointed out, indicating that the greater rigidity of the vitrified bond can be harmful during the grinding of workpieces with interrupted geometry. Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Dept Elect Engn, Bauru campus, Bauru, SP, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Dept Elect Engn, Bauru campus, Bauru, SP, Brazil FAPESP: 2017/03788-9 FAPESP: 2018/22661-2

Made available in DSpace on 2020-12-12T02:44:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-06-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) The use of cutting fluid in the grinding process is crucial to guarantee quality in the products. However, most cutting fluids can cause disease to operators and damage the environment, which adds costs to the industry, as well as a deficit in the operator’s quality of life. In addition, the metalworking industry has as problem control corrosion in their parts; it demands to add the process of remove cutting fluid of the workpieces and add a protective oil on their surface. In this context, a new class of corrosion inhibitors that use water as a propagation medium, generically known as V-active® VCI, was formulated, which made it possible to develop, firstly, a cutting fluid with the addition of such inhibitor, called generically VCI 1, which would eliminate the process of degreasing and adding protective oil. Previous research has indicated the VCI 1 has an excellent performance in the grinding process, which promoted the development of two other new fluids (named generically VCI 2 and VCI EP) at a reduced market cost to make the product more competitive. In addition to the cost savings compared with the VCI 1, the VCI EP has the differential of an extreme pressure additive. It is noteworthy that the fluids in question pose no risk to humans and are biodegradable. Thus, the performance of these two new fluids with a corrosion inhibitor was verified in the grinding process of AISI 4340 steel with an aluminum oxide grinding wheel and the results were compared with the higher market cost V-active® VCI fluid and with a base fluid without the corrosion inhibitor. The comparison took place at three different feed rates (0.25, 0.50, and 0.75 mm/min). For each feed rate, the following were evaluated: surface roughness; roundness error, diametral grinding wheel wear, microhardness, optical microscopy, and acoustic emission, and the ground surface was analyzed using scanning electron microscopy (SEM). Therefore, useful information was obtained for the technological development of the rectification process, thus adding to scientific knowledge and dissemination of knowledge to society. Department of Mechanical Engineering School of Engineering São Paulo State University (UNESP) Department of Control and Industrial Processes Federal Institute of Education Science and Technology of Parana, Jacarezinho Campus, Jacarezinho VCI Brasil, Rod. Marechal Rondon KM 334,3 Department of Electrical Engineering School of Engineering São Paulo State University Department of Mechanical Engineering School of Engineering São Paulo State University (UNESP) Department of Electrical Engineering School of Engineering São Paulo State University FAPESP: 2015/09868-9 FAPESP: 2017/03788-9 FAPESP: 2017/03789-5 CNPq: 312588/2006-2

Made available in DSpace on 2020-12-10T20:03:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-06-23 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Abrasion machining has stood out in the current industry due to constant improvements in the dimensional accuracy of a workpiece in its finishing process. Thus, it is necessary to use cutting fluid to cool and lubricate the workpiece-wheel contact, to reduce both the high temperatures reached and the friction. However, conventional cutting fluid is harmful to the environment and poses a risk to the operator's health. As a result, the minimum lubricant quantity (MQL) technique emerged, using extremely smaller amounts of fluid and, however, showing excellent results in its applications. In this way, it could further optimize this method through studies on oil dilution, combating low cooling capacity. A fundamental concept for selecting the grinding wheel type to be used in grinding is friability, but there are few studies on its influence on the process. For these reasons, this research analyzed the impact of friability and the effects of MQL dilution on the grinding of austempered ductile iron, the use of two CBN wheels with high and low friability, and four types of lubri-refrigerant methods: flood, pure MQL, and diluted MQL in the oil-water ratio 1:5 and 1:10. Output parameters were analyzed: surface roughness (Ra), roundness error, diametrical wheel wear, cutting power, acoustic emission, viscosity, 3D confocal, and microhardness. The results show an improvement of the diluted MQL over the pure, coming close to the conventional method. Besides, the low friability wheel was more efficient in the analysis of surface roughness, roundness error, and diametrical wheel wear. However, most friable stood out in the results of acoustic emission and grinding power. Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil Fed Inst Parana, Dept Control & Ind Proc, Jacarezinho Campus, Jacarezinho, Parana, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Dept Elect Engn, Bauru Campus, Bauru, SP, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Dept Elect Engn, Bauru Campus, Bauru, SP, Brazil FAPESP: 2016/23910-0 FAPESP: 2018/22661-2 FAPESP: 2019/24933-2

Made available in DSpace on 2020-12-10T20:00:07Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-05-25 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Among conventional machining processes, grinding presents itself as a material removal process that can produce workpiece with excellent surface finish and high geometric precision. Given the high industrial demand, more and more machining methods are being sought to allow high production speeds coupled with reduced costs. The requirement for high productivity and low-cost grinding processes often bumps into the geometry of the desired workpiece. Numerous grounded components in the automotive, aeronautics, and naval industries have geometric interruptions, such as ring seating channels and lubrication ducts. Interrupted grinding leads to shorter tool life and can lead to a decrease in the dimensional and surface quality of the mechanical component, thus requiring grinding of these components at low speeds. Thus, the present paper shows an experimental evaluation of interrupted cylindrical grinding of hardened steel AISI 4340 with vitrified aluminum oxide grinding wheel. Interrupted circular workpieces (2, 6, and 12 channels) were applied to simulate interruptions found in mechanical components subjected to interrupted grinding at feed rates of 0.25, 0.50, and 0.75 mm/min, at cutting speed of 32 m/s, under conventional lubrication, compared with uninterrupted workpieces under the same machining conditions. The output parameters evaluated were surface roughness, roundness deviation, grinding power, micrography, diametral wheel wear, and G-ratio, being evaluated statically by analysis of variance (ANOVA). There were no verified regions with burning or microcracks in all conditions. Still, the increase in the rate of advancement generated a drop of up to 68.7% in surface roughness, 40.5% in shape errors, and an increase in diametrical degreasing of the average grinding wheel of 90.9%. The wheel wear was more accentuated due to the number of interruptions, reaching a wear rate of up to 252% higher than the conventional condition. Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil FAPESP: 2018/22661-2

Made available in DSpace on 2020-12-10T19:57:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-04-27 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) This work aimed to study the application of minimum quantity of lubricant (MQL) with the addition of water, respecting the proportions 1:0, 1:5, 1:10, and 1:20 oil-water, in the cylindrical grinding of austempered ductile iron (ADI). Also, two cubic boron nitride (CBN) grinding wheels, with distinct friability levels, were used. The analysis of surface roughness (Ra), roundness error, G-ratio, grinding power consumed, specific grinding energy, microhardness, and microstructure was done using confocal and optical microscopy. The results show that the addition of water to the MQL mixture significantly improves its characteristics. Thus, MQL 1:5 (oil-water) produced the best results among the alternative methods analyzed. Also, all MQL variations did not produce microstructural change or thermal damage to the workpieces. Besides, the less friable grinding wheel (CBN GL) produced better surface quality of the workpieces and caused less wheel wear compared with the more friable wheel (CBN GS). On the other hand, the more friable wheel used less power during the grinding. Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil Fed Inst Parana, Dept Control & Ind Proc, Jacarezinho Campus, Jacarezinho, Parana, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Dept Elect Engn, Bauru Campus, Bauru, SP, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Dept Elect Engn, Bauru Campus, Bauru, SP, Brazil FAPESP: 2016/23910-0 FAPESP: 2018/22661-2

Made available in DSpace on 2020-12-10T19:49:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-01 The minimum quantity lubrication + nanofluid technique has proven to be feasible in machining processes, since it has shown potential for improvements through its lubri-refrigeration and heat removal characteristics, beyond increase the surface quality workpiece surface, while minimizing diametrical wheel wear. Also, the nanofluids are associated with decreasing the grinding power corroborates for process efficiency. In this way, this work evaluates the combination of the MQL + nanofluid (MQL + Nano) technique and compares its results with the cutting fluid abundant application (Flood) technique, traditional MQL and MQL associated with wheel cleaning jet (MQL + WCJ). Accordingly, the process output variables were analyzed: surface roughness (Ra), roundness error, diametral wheel wear, optical microscopy and microhardness from the workpiece ground surface, grinding power, specific energy grinding, acoustic emission, cutting fluid viscosity and transmission electron microscopy of the TiO2 nanoparticle used. The techniques applied in this work did not cause microstructural alteration in the workpieces, proving that the lubri-refrigeration methods are efficient. Even though the cutting fluid viscosity decreased by about 60% with the addition of TiO2 nanoparticles and the application of the MQL + Nano technique proved to be efficient in comparison to the traditional MQL, the MQL + WCJ application presented the best results among the alternative lubri-refrigeration techniques. Thereby, the MQL + WCJ corroborated to a better workpiece surface quality, while presented the lower diametrical wheel wear, surface roughness and roundness error values, contributing to the minimization of the industrial residues and cooperating with the environment and health of the worker. Sao Paulo State Univ, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil Sao Paulo State Univ, Dept Chem, Bauru Campus, Bauru, SP, Brazil Fed Inst Parana, Dept Control & Ind Proc, Jacarezinho Campus, Jacarezinho, Parana, Brazil Sao Paulo State Univ, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil Sao Paulo State Univ, Dept Chem, Bauru Campus, Bauru, SP, Brazil

Made available in DSpace on 2020-12-10T19:38:51Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-10-21 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) In the last decades, manufacturers attracted much attention to developing processes with competitivity, sustainability, and productivity. One of the most important developments was related to employing more efficient tools. CBN was developed to improve the performance of the abrasive materials by higher hardness, thermal conduction, and chemical stability. In this sense, not only abrasive grains' properties are important for tool performance, but also bonds are essential for the consolidation of CBN abrasives in manufacturing industry. In order to contribute to findings about the performance of applied bonds in CBN grinding wheels, this work aims to compare CBN grinding wheels composed of vitrified bond and resinoid bond. The workpiece material was AISI D6 special steel which is widely used to manufacture stamping matrix, and this application requires parts with high geometrical and dimensional precision, also high-quality surface finish. For the results analysis and discussion, tangential grinding force and acoustic emission were monitored in order to analyze the process efficiency and surface roughness and G ratio was measured; besides scanning electron, confocal microscopy and optical microscopy were used for the analysis of the ground surface. The vitrified bond provided more efficient results in terms of surface roughness and G ratio in comparison with resinoid bond. However, acoustic emission and tangential grinding force were lower in grinding with CBN resinoid bond what indicated lower mechanical loads. Therefore, this paper presents relevant information to select the appropriate bond to CBN grinding wheel application. Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil FAPESP: 2015/09197-7 FAPESP: 2015/09868-9 FAPESP: 2017/03788-9

Made available in DSpace on 2019-10-06T17:16:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-01-01 Made available in DSpace on 2019-10-06T17:16:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-01-01 Due to the characteristics of the grinding process, thermal damage may occur in the workpiece surface, resulting in the rejection of a component and considerably increasing the production costs. This study aims to analyze the heat fluxes, energy partition, and temperatures during surface grinding process with both conventional and MQL lubrication. Through the proposed analysis, the heat fluxes and maximum temperature can be predicted, enabling the avoidance of thermal damages and increasing the efficiency of the process. A comparison between the calculated and experimental value has shown that the difference is acceptable for various situations, in the order of 4.72% for the conventional method and 7.38% for the MQL method. A thermal model was developed. The transient two-dimensional heat diffusion equation was discretized by finite volume method in space and explicit discretized in time. The heat fluxes were estimated using inverse problem technique of heat transfer aiming the obtainment of the temperature of certain workpiece points. A comparison of the methods of lubrication showed that the conventional method was way more efficient than MQL, presenting considerably lower total heat flux and maximum reached temperature and any kind of thermal damage wasn’t observed. On the other hand, thermal damage occurred in the workpieces. Also, clogging phenomenon in the grinding wheel surface after the process in MQL condition was observed. Department of Mechanical Engineering College of Engineering College of Engineering São Paulo State University (UNESP) Department of Mechanical Engineering Federal University of Technology Paraná (UTFPR) Department of Electrical Engineering College of Engineering São Paulo State University (UNESP) Department of Mechanical Engineering College of Engineering College of Engineering São Paulo State University (UNESP) Department of Electrical Engineering College of Engineering São Paulo State University (UNESP)

Made available in DSpace on 2019-10-04T12:39:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-07-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Composite materials are becoming essential and widely used in modern industry, mainly in aeronautics, aerospace, and naval sectors. The reason for its increasing use is their structural composition, a combination of two different materials, resulting in a low weight, extremely rigid, and resistant. Due to the material's anisotropy, it tends to present residual stresses or structural distortions. Recent researches show that the finishing machining process called grinding is the most recommended for eliminating these structural problems. In grinding process, there needs to be a great amount of cutting fluid (flood cooling), and the surface wear is high. The abundant application of these fluids has become a factor of concern for the modern industries, due to the issues related to occupational health and environmental hazard because of their toxic compounds. In reference to these concerns, arises a new methods of application as well the optimized cooling, the minimum quantity lubrication (MQL) technique and dry grinding. This way, this work analyzed the behavior of the surface grinding of carbon fiber reinforced plastic (CFRP) composites using optimized cooling, MQL, and dry cutting as an alternatives to the conventional coolant technique by SEM images of workpiece surface. Surface roughness, grinding force, specific grinding energy, and G ratio were also analyzed. SEM images showed the difference on fiber surface which is produced by the increase of the depth of cut and different lubrication methods adopted. With the results obtained, the MQL technique generated the lowest grinding values and grinding specific energy. The optimized and flood methods provided the lowest wear of the grinding wheel, as well as the better surface finishing. Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Inst Sci & Technol, Sorocaba Campus, Sorocaba, SP, Brazil Fed Inst Sao Paulo, Inst Sci & Technol Sao Paulo, Itapetininga Campus, Itapetininga, SP, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Inst Sci & Technol, Sorocaba Campus, Sorocaba, SP, Brazil FAPESP: 2015/09197-7

Made available in DSpace on 2019-10-04T12:36:51Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-05-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) High thermal loads generated during grinding of ceramic materials increase abrasive tool wear and damage workpiece quality. In this regard, the application of cutting fluid has been mandatory, although several researchers have been working to reduce oil consumption in such processes, as it increases the cost of the final product and is harmful to both people and environment. Among the alternatives, minimum quantity lubrication (MQL) has been increasingly investigated, even though clogging of the grinding wheel is prone to occur. In order to improve the cleaning of the abrasive tool during the process and reduce oil consumption, this paper proposes the investigation of the performance of MQL technique applied together with a wheel cleaning system, which consists of a compressed air jet directed to the wheel surface, during grinding of alumina. Different direction angles of the air jet were tested and conventional flood coolant as well as MQL alone were applied for comparison purposes. Flood coolant was the most efficient method regarding cleaning of the grinding wheel, decrease of diametral wheel wear, surface roughness, and average power followed by the use of MQL with an air jet directed to the wheel surface with an angle of 30 degrees. This latter arrangement, however, can become an option when the reduction of oil consumption is a priority, as it provides the best results when compared to the other air jet direction angle configurations. Sao Paulo State Univ, Dept Mech Engn, Av Luiz Edmundo Carrijo Coube 14-01,Mailbox 473, BR-17033360 Bauru, SP, Brazil Univ Fed Sao Carlos, Dept Mech Engn, Rod Washington Luis Km 235, BR-13565905 Sao Carlos, SP, Brazil Sao Paulo State Univ, Dept Elect Engn, Av Luiz Edmundo Carrijo Coube 14-01,Mailbox 473, BR-17033360 Bauru, SP, Brazil Sao Paulo State Univ, Dept Mech Engn, Av Luiz Edmundo Carrijo Coube 14-01,Mailbox 473, BR-17033360 Bauru, SP, Brazil Sao Paulo State Univ, Dept Elect Engn, Av Luiz Edmundo Carrijo Coube 14-01,Mailbox 473, BR-17033360 Bauru, SP, Brazil FAPESP: 2015/10460-4 FAPESP: 2017/03789-5

Grinding is a finish process of parts that require high precision and tight dimensional tolerance, which owe high value-added. As the grinding process takes place, the cutting surface of the grinding wheel undergoes wear and then its cutting capacity is reduced. On the other hand, the dressing operation is responsible for restoring the cutting surface of the grinding wheel and, therefore, plays a key role in the grinding process. This work aims at obtaining acoustic images of the grinding wheel surface to identify its conditions during the dressing operation. Experimental tests were conducted with a single-point diamond dresser in a surface grinding machine, which was equipped with an oxide aluminum grinding wheel in which specific marks were intentionally made on its surface to simulate damages for identification. An acoustic emission sensor was fixed to the dresser holder and the signal were acquired at 5 MHz. The signal spectrum was investigated and a frequency band was carefully selected, which represented the conditions of grinding wheel surface. The root mean square values were then computed from the raw signal with and without filtering for several integration periods, and the acoustic images obtained. The results show that the proposed technique is efficient to identify the damage on the wheel surface during the dressing operation as well as its location.

Made available in DSpace on 2021-06-25T12:39:19Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-03-02 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) With the evolution of the sustainable industry, the grinding process seeks to follow the requirements to continue to be highly employed when precision and low-dimensional tolerances are required in the workpieces. In this way, the cutting fluids used in the process, which are essential for a good surface finish, are the main impasse to ensure that the process becomes eco-friendly. Therefore, a widespread lubri-refrigeration method in the industry is the flood technique, which uses a lot of fluid to reduce the high temperatures generated during grinding. However, the use of the flood method generates many undesirable residues that affect the machine operator, the environment, and production costs. Thus, several alternatives have emerged to address these problems, for example, the minimum quantity of lubricant (MQL), the wheel cleaning jet system (WCJ), and the application of cooled air (CA). Therefore, this work sought to analyze the combination of these systems (MQL+CA, MQL+WCJ, and MQL) in the grinding of AISI 4340 steel using an aluminum oxide wheel (Al2O3) and to verify their performance compared with the flood method, in addition to employing a new method known as cooled wheel cleaning jet (CWCJ). Therefore, the tests of surface roughness (Ra and Rz), roundness error, diametrical wheel wear, G ratio, grinding power, tangential cutting force, and microhardness were performed, and optical, confocal, and scanning electron microscopy also were analyzed. Thus, the results that came closest to the flood method in all tests were achieved by systems that applied grinding wheel cleaning (MQL + WCJ and MQL + CWCJ), being that in the diametrical wheel wear and G ratio the MQL + CWCJ even managed to surpass it. Besides, the MQL+CA union showed better values when compared with MQL without any assistance. Thus, applying MQL with helper systems, mainly CWCJ, contributed to a more economical, efficient, and sustainable grinding process. Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Sch Sci, Bauru Campus, Bauru, SP, Brazil Univ Fed Amazonas, Manaus Campus, Manaus, Amazonas, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Sch Sci, Bauru Campus, Bauru, SP, Brazil FAPESP: 2019/24933-2 FAPESP: 2020/06038-3

Made available in DSpace on 2021-06-25T11:10:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-03-01 Indirect methods to monitor the surface integrity of grinding wheels by acoustic emission (AE) have been proposed, aiming to ensure their optimal performance. However, the time-frequency analysis of the content of these signals has not been addressed in the literature. AE signal analysis performed only in the frequency domain makes it impossible to locate faults on the grinding wheel surface during the dressing operation and examine the behavior of the frequencies contained in these signals over time. In this regard, the time-frequency analysis of AE signals during dressing through STFT (short-time Fourier transform) can contribute toward the proposal of new monitoring methodologies, thus reflecting the optimization of the grinding process. This paper proposes an algorithm based on the Kaiser window to adjust the STFT parameters to ensure an appropriate balance between time-frequency resolutions. Besides, this algorithm is used to investigate the characteristic frequencies in the aluminum oxide grinding wheel in dressing operation. The results indicate that the spectral content of the AE signals during dressing follows a uniform behavior, but their amplitude changes depending on the characteristics of topography and sharpness of the grinding wheel cutting edges. Electrical Engineering Department São Paulo State University (UNESP), Av. Eng. Luiz Edmundo C. Coube 14-01 Control and Automation Engineering Department Pará Federal Institute of Education Science and Technology (IFPA), Campus Parauapebas, PA 275, s/n, União Mechanical Engineering Department São Paulo State University (UNESP), Av. Eng. Luiz Edmundo C. Coube 14-01 Electrical Engineering Department São Paulo State University (UNESP), Av. Eng. Luiz Edmundo C. Coube 14-01 Mechanical Engineering Department São Paulo State University (UNESP), Av. Eng. Luiz Edmundo C. Coube 14-01

Made available in DSpace on 2021-06-25T12:33:19Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-02-10 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Norton Abrasives Co. (Saint Gobain) ITW Chemical Products Eco-efficiency solutions have been more and more proposed by researcher and industry around the world in latest years in order to become the manufacturing systems cleaner and greener. This action is related to the global warning about the generation of greenhouse gases (GHGs), like CO2, as reported by Intergovernmental Panel on Climate Change (IPCC) . One of the most hazardous issue related to environmental risk in machining process is the application of metalworking fluids (MWFs), especially in grinding process in which MWFs are pivotal to control high generation of heat and avoid workpiece surface burns and microstructural changes. The minimum quantity lubrication (MQL) was broadly reported in the literature as a potential alternative lubri-cooling technique to the conventional technique (flood F). However, the main drawback of MQL grinding is related to high generation of clogging phenomenon produced by the chips lodged on the grinding wheel active surface (GWAS) due to the low oil volume and consequently the low lubricating and cooling action. In order to propose improvements on MQL technique, increase its efficiency and viability and develop a potential greener lubri-cooling technique, this work aims to propose and evaluate the application of hybrid HMQL + WCJ technique combined oil and water at 1:5 oil-water in the Al2O3 grinding process of AISI 4340 steel. This technique was compared to flood F and the pure PMQL + WCJ (pure oil) techniques. Both MQL techniques (hybrid and pure) employed at 30, 60 and 120 mL/h. The PMQL + WCJ technique produced the worst results irrespective of the flow rate. The HMQL + WCJ at 120 mL/h (highest flow rate) presented similar performance to the F technique in terms of surface roughness, microhardness, clogging behavior on GWAS, workpiece form deviation, grinding power, generation of CO2 during the process and acoustic emission (AE) and outperformance in terms of G ratio. This indicates the eco-efficient potential to be widely employed in manufacturing industry and mitigate the environmental impact and carbon footprint of hybrid MQL + WCJ technique. (C) 2020 Elsevier Ltd. All rights reserved. Sao Paulo State Univ Julio Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil Univ Estadual Campinas, Sch Mech Engn, Campinas, SP, Brazil Sao Paulo State Univ Julio Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil

Made available in DSpace on 2022-04-29T08:31:52Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Technological advances and the development of new products make it increasingly necessary to seek to improve production means to meet the growing demand for equipment and consumer goods. In this sense, the molds enable the large-scale production of complex workpieces and equipment, which could hardly be manufactured through conventional machining. Also, the molds’ surface quality must be high to avoid deviations in the produced workpieces, being achieved through grinding. Thus, this work evaluates the performance of the VP50IM mold steel grinding process using feed rates of 0.25, 0.50, and 0.75 mm/min under the conventional lubrication method, comparing the results obtained with conventional wheels of white aluminum oxide, green silicon carbide, and white aluminum oxide and black silicon carbide grain tool. The comparison was made considering the results of surface roughness (Ra), roundness error, acoustic emission, G-ratio, diametrical wheel wear, tangential grinding force, grinding power, microhardness, microscopies, and grinding costs. The results’ analysis shows an advantage of using the green silicon carbide grinding wheel, which even in the worst scenario (0.75 mm/min) presented 14.83% less wear, 10.81% less acoustic emission, and consumed 10.18% less grinding power in comparison to the black silicon carbide wheel, with even better results when compared to the white aluminum oxide. Meanwhile, grinding with green silicon carbide wheel produced 9.88% lower surface roughness and 4.80% less roundness error in the worst condition when compared to the black silicon carbide tool. The machining costs with green silicon carbide were very close to those observed in the grinding with white aluminum oxide and the black silicon carbide, corroborating the grinding advantage of the VP50IM mold steel with a green silicon carbide wheel. Department of Mechanical Engineering São Paulo State University “Júlio de Mesquita Filho,” Bauru campus, Bauru Department of Control and Industrial Processes Federal Institute of Paraná Jacarezinho campus, Jacarezinho Department of Electrical Engineering São Paulo State University “Júlio de Mesquita Filho,” Bauru campus, Bauru Department of Mechanical Engineering São Paulo State University “Júlio de Mesquita Filho,” Bauru campus, Bauru Department of Electrical Engineering São Paulo State University “Júlio de Mesquita Filho,” Bauru campus, Bauru

Made available in DSpace on 2020-12-10T19:57:24Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-08-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) The main difficulty in the grinding process is to identify the correct moment to dress the grinding wheel. Therefore, the cutting tool (grinding wheel) must be monitored. In this context, an innovative technique was developed in this article to obtain an image from the surface of the grinding wheel during the dressing process, based on acoustic images acquired through a piezoelectric diaphragm or piezoelectric buzzer. To this end, scratches (faults) are made on a grinding wheel, after which tests are performed at various dressing depths, and signals are collected by an acoustic emission (AE) sensor and a piezoelectric diaphragm. Based on these signals, frequency bands are evaluated to obtain acoustic images that would accurately and clearly represent the scratches imprinted on the grinding wheel. Finally, the performance of the two sensors (AE sensor and piezoelectric diaphragm) are compared, and the results are analyzed in light of the dressing conditions under study. The results indicate that the piezoelectric diaphragm is as efficient in obtaining acoustic maps of the grinding wheel surface as the AE sensor and in some machining conditions, it provides superior results to those obtained when monitoring the tool with the AE sensor. Sao Paulo State Univ, Dept Elect Engn, BR-17033360 Bauru, SP, Brazil Para Fed Inst IFPA, BR-68515000 Parauapebas, Brazil Sao Paulo State Univ, Dept Mech Engn, BR-17033360 Bauru, SP, Brazil Sao Paulo State Univ, Dept Elect Engn, BR-17033360 Bauru, SP, Brazil Sao Paulo State Univ, Dept Mech Engn, BR-17033360 Bauru, SP, Brazil CNPq: 306435/2017-9

Made available in DSpace on 2020-12-10T19:50:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-02-25 company Nikkon Ferramentas de Corte Ltda - Saint Gobain Group Quimatic Tapmatic Ltda Although the fact that the interrupted cutting process is widely employed in traditional machining operations such as turning of crankshafts, engine piston ring, and helical tool sharpening, only a few number of studies in the literature approach this process. This study aims to evaluate the performance of the interrupted grinding process of workpieces with a different number of grooves (2, 6, and 12) in CBN grinding and to contribute to further findings about the integrity of interrupted surfaces and groove flanks after grinding, analyzing surface roughness and roundness deviation of workpieces after grinding process. The diametric wheel wear and grinding power were also recorded and analyzed. The performance of the interrupted grinding process was compared with the continuous grinding process, i.e., for workpieces without grooves. The AISI 4340 steel workpieces were tested under the application of flood lubri-cooling method at different feed rates (0.25, 0.50, and 0.75 mm/min). In conclusion, higher feed rate increased the surface roughness from 0.12 to 0.35 mu m for continuous grinding process, respectively at 0.25 and 075 mm/min. The interrupted grinding led to increase of surface roughness Ra values from 0.19 to 0.43 mu m (respectively 58.3% and 22.9% higher than continuous) for 2 grooves, 0.31 to 0.59 mu m (respectively 158.3% and 68.6% higher than continuous) for 6 grooves and 0.54 to 0.93 mu m (respectively 341.7% and 165.7% higher than continuous) for 12 grooves, respectively at 0.25 and 0.75 mm/min. As presented for surface roughness values, the increase of groove number resulted in higher values of roundness deviation, diametric wheel wear due to mechanical shocks caused by couplings and uncouplings of the grinding wheel. It was evidenced by SEM images of groove flanks and macro-fracture mode of abrasive grains. No microstructural damage was caused by thermal or mechanical irrespective of the experimental conditions investigated. Sao Paulo State Univ, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil Sao Paulo State Technol Coll, Botucatu Campus, Botucatu, SP, Brazil Univ Sao Paulo, Sch Engn Sao Carlos, Sao Carlos, SP, Brazil Sao Paulo State Univ, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil

Made available in DSpace on 2020-12-10T19:54:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-06-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Cutting fluids have a fundamental role in machining, especially in grinding, since they are responsible for lubrication and refrigeration of the cutting region. On the other hand, they may cause damage to the environment and to the health of the operators. Thermal damage, geometric inaccuracies and degradation of the surface integrity of the workpiece are diminished with the use of cutting fluids. While in the conventional application of cutting fluid a large amount of oil or emulsion of oil with water is used, in the minimum quantity lubrication (MQL) technique a small amount of oil is applied via a jet of compressed air reaching, in many cases, results comparable to the conventional method. However, the lower cooling capacity of MQL and the clogging of the wheel pores caused by the hot chips are obstacles to be overcome. This work evaluates the addition of water to the MQL method in the external cylindrical plunge grinding of AISI 52100 steel to improve the deficiencies of this technique. The results analyzed include surface roughness (Ra), workpiece surface damages, roundness deviation, grinding wheel wear, grinding power, acoustic emission, workpiece subsurface microhardness and microstructure for conventional method, MQL with pure oil (1:0) and MQL with water in 1:1, 1:3 and 1:5 oil-water proportions with and without grinding wheel cleaning (a jet of compressed air towards the wheel surface to remove the chips which clog the wheel pores). MQL with pure oil produced the worst results in this work, but dilution of oil in water benefited this lubricant-refrigerant technique. In addition, the diluted MQL 1:5 associated with wheel cleaning jet (WCJ) was the alternative method that most closely approximated the results of the conventional technique, indicating the potential for using MQL with WCJ widely in the industry. However, it is necessary to continue researching this technique in order it could even outperform the conventional method in all its output variables. (C) 2020 Elsevier Ltd. All rights reserved. Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil Univ Estadual Campinas, Sch Mech Engn, Campinas, SP, Brazil Univ Sao Paulo, Sao Carlos Sch Engn, Dept Mech Engn, Sao Carlos, SP, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil FAPESP: 2018/22661-2

Made available in DSpace on 2020-12-10T19:45:48Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Post Graduate Program of Mechanical Engineering of UFU Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) The search for more sustainable grinding processes resulted in alternative cooling-lubrication techniques, as minimum quantity lubrication (MQL). However, this shift changes the associated tribosystem and, thus, the surface topography. This work investigates the topography of SAE 4340 steel after grinding with different cooling-lubrication techniques: flood, MQL and MQL with cleaning system (MQL + CS). The topography was analyzed through several roughness parameters and SEM. The results showed that surfaces ground with the MQL and MQL + CS presented larger bearing areas and lower peaks and valleys dispersion. The MQL technique, especially the MQL + CS, also lowered the grinding wheel wear by better cleaning the wheel pores. Furthermore, the CS was efficient at removing debris that adhered to the wheel and improved lubrication of the tribosystem. Univ Fed Uberlandia, Sch Mech Engn, Uberlandia, MG, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil CAPES: 001 Post Graduate Program of Mechanical Engineering of UFU: 141472/2017-0 CNPq: 141472/2017-0 CNPq: PQ/2016 CNPq: 311337/2016 CNPq: 426018/2018-4

Made available in DSpace on 2022-05-01T11:07:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-01-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Minimal Quantity of Lubrication was developed to achieve green manufacturing in machining process. In this study, parameters of cutting fluid flow, grinding wheel type and wheel cleaning system were evaluated to achieve the maximum potential of this technique in grinding process. The comparison of super abrasive (CBN) and conventional (Al2O3) grinding wheel, the cutting fluid flow (30 ml/h, 60 ml/h and 120 ml/h), and the wheel cleaning system were analyzed based on: surface roughness, roundness errors, grinding wheel wear, confocal of grounded surface, grinding power, acoustic emission and workpiece microscopy. In a novel way, this study compared the costs per piece and the carbon footprint in terms of CO2 emission for both abrasive tool application. For all the parameters analyzed, the CBN grinding with MQL outperformed the Al2O3 grinding, showing a superior performance not only in terms of surface finishing, on average, 29% lower surface roughness and dimensional deviation 9% lower but also regarding tool efficiencies, such as 127% lower diametrical wear, 42% lower acoustic emission, and 13% lower grinding power. Despite that, the cost per piece was also evaluated for the different lubri-cooling conditions and tools, and the cost per piece recorded for Al2O3 grinding was substantially lower than CBN grinding, irrespective of the lubri-cooling method employed. The cost of grinding for all MQL techniques analyzed with aluminum oxide wheel was, on average, 72% less than grinding with CBN wheel. Besides, the conventional method with the CBN wheel was 7% more expensive than the aluminum oxide wheel. Sao Paulo State University – Unesp Department of Mechanical Engineering São Paulo State University “Júlio de Mesquita Filho” Department of Electrical Engineering Imperial College London Department of Mechanical Engineering, Exhibition Rd. Sao Paulo State University – Unesp Department of Mechanical Engineering São Paulo State University “Júlio de Mesquita Filho” Department of Electrical Engineering

Made available in DSpace on 2020-12-10T19:42:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-12-01 The hardening of legislation in favor of socio-environmental preservation and the sustainable focus of industry are changing the current manufacturing methods, among which is grinding. This abrasion machining technique aims to produce parts with excellent surface finish and high geometric precision. On the other hand, the multiple sharp edges of the abrasive grains that make up the grinding wheel simultaneously deform and shear the workpiece surface material, which releases a lot of energy in the form of heat. In this context, to soften the damage caused by the high temperatures, cutting fluids are applied to lubricate and refrigerate the tool/workpiece interface during the grinding process. However, the use of these fluids is damaging to people's health and carries a high cost for disposal, given their potential to impact the biosphere. In this sense, the society allied with the researchers seeks alternative methods of lubri-refrigeration, among them, the minimum quantity lubrication (MQL), which applies a small quantity of fluid to the cutting zone through a flow of compressed air. However, the excessive increase of machining temperatures and the intensification of the grinding wheel clogging are significant drawbacks of this technique. Thus, to mitigate these problems, this work seeks to evaluate the traditional MQL application, MQL with cooled air (MQL+CA), and assisted by a wheel cleaning jet (MQL+WCJ), comparing them with the conventional method with abundant fluid, in the external cylindrical plunge grinding of the AISI 4340 steel using an aluminum oxide grinding wheel. The output parameters used to assess the efficiency of the techniques were surface roughness, roundness error, diametrical wheel wear, grinding power, tangential cutting force, specific grinding energy, and microhardness. The machined surfaces were evaluated through optical and scanning electron microscopies to verify possible thermal damages and microstructural alterations, and optical microscopy images of the grinding wheel cutting surface were assessed to ascertain the occurrence of the wheel clogging phenomenon. The results of the tests showed that the conventional method produced the best results in all analyzed parameters. Besides, MQL+WCJ and MQL+CA outperformed all the results obtained with traditional MQL, which revealed the improvement obtained with these eco-friendly techniques and their applicability in the industry. Moreover, the application of the MQL+WCJ provided the closest results in comparison with the conventional method, proving to be superior to the MQL+CA. Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil Fed Inst Parana, Dept Control & Ind Proc, Jacarezinho Campus, Jacarezinho, Parana, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Dept Elect Engn, Bauru Campus, Bauru, SP, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Dept Elect Engn, Bauru Campus, Bauru, SP, Brazil

Made available in DSpace on 2020-12-10T19:42:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-12-01 Nowadays, environmental concern and the search for environmentally friendly techniques have contributed to industrial development towards sustainability. Production without social and environmental impact is one of the main goals of engineering research. Although analysis is carried out, some manufacturing processes still require studies, such as grinding, for example. In this process, the interaction between the grinding wheel and workpiece generates a significant amount of heat, due to shearing, friction, and scratching caused by the contact of the numerous abrasive grains with the workpiece surface. The heat generated at the interface has a more intense flow to the workpiece, which can cause several microstructural damages, as well as providing shape errors and increased grinding wheel wear. Thus, the application of cutting fluid is indispensable to minimize the harmful effects caused by heat to the grinding wheel and the workpiece during the process. However, the industry commonly uses soluble cutting fluid, having oil in its composition, in addition to chemical components that prevent its degradation, due to recirculation in the system and the need to avoid the accumulation of bacteria, whereas its application has a flow rate of tens of liters per minute. These cutting fluids will be discarded at some point, which will require complex waste treatment processes for proper disposal. An alternative to this type of application is the minimum quantity lubrication (MQL), which consists of a few milliliters per hour, but which has low refrigerant power. Some techniques have been developed to enhance its application and make it more refrigerant, such as the application of a jet of compressed air directed to the grinding wheel cutting surface to perform the cleaning, minimizing the heat generation by the reduced agglomeration of chips in the grinding wheel pores. Therefore, this work analyzed the cylindrical plunge grinding of hardened steel workpiece with cubic boron nitride grinding wheel on different cooling conditions, comparing the conventional cutting fluid application method (flood) with the MQL technique, MQL simultaneously with the wheel cleaning jet (MQL + WCJ) and MQL with cutting fluid applied at 0 degrees C (MQL + CA). The performance of each method was analyzed by using the measurements of surface roughness (Ra), roundness error, diametral wheel wear, power consumed during the process, specific energy grinding, microhardness, and microstructural analysis to investigate possible modifications of the microstructure of the workpiece. It was found that in none of the cases, there were microstructural alterations, but the MQL application method presented the worst values of the variables among the techniques studied, whereas the application on low temperature showed potential to be used in a large scale. Nevertheless, the MQL application method applied simultaneously with the wheel cleaning jet (WCJ) has presented the closest values of the conventional method; it becomes the most feasible method for application in the industry towards the protection of the environment and health of the workers. Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil Univ Sao Paulo Sao Carlos, Sch Engn, Sao Carlos, SP, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil

Made available in DSpace on 2018-11-12T17:28:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-07-01. Added 1 bitstream(s) on 2018-11-12T17:36:18Z : No. of bitstreams: 1 S2448-167X2018000300397.pdf: 806253 bytes, checksum: d70d36a91b2e55081523f6244200bafe (MD5) Abstract The grinding process is defined as an abrasive cutting action of a tool known as grinding wheel, which is submitted to high rotations, promoting excellent finishing and accuracy in dimensions, respecting the parameters established in each project. During the machining, the cutting edges of the abrasive grains undergo wearing and this increases the contact surface of the tool with the workpiece, increasing the machining temperature and creating possibilities of damaging it. Therefore, it is necessary to use a cutting fluid, responsible for lubricating and cooling the cutting zone, removing the chips from the cutting region between the workpiece and the wheel, and even having an anticorrosive action. However, its composition causes contamination to the environment and to the operator. In face of the increasingly strict environmental laws, it has become necessary to search for new methods of cooling that are at least as effective as conventional one and economically practicable. Thus, the Minimum Quantity of Lubrication was developed as a mist of air and oil applied at high pressure, reducing drastically the use of contaminants. In this work, two oil flows were used for the MQL technique, 30 ml/h and 120 ml/h. The wheel used was a CBN (Boron Cubic Nitride) one, composed of synthetic grains and the workpiece, in a ring format, were produced in AISI 4340 steel quenched and tempered. It was observed from results that MQL can be applied in the industrial processes without losing piece quality. Universidade Estadual Paulista Julio de Mesquita Filho Departamento de Engenharia Mecânica Universidade Estadual Paulista Júlio de Mesquita Filho Departamento de Engenharia Mecânica Universidade Estadual Paulista Julio de Mesquita Filho Departamento de Engenharia Mecânica Universidade Estadual Paulista Júlio de Mesquita Filho Departamento de Engenharia Mecânica

Made available in DSpace on 2018-12-11T17:37:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-09-01 Made available in DSpace on 2018-12-11T17:37:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-09-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) The extensive tribological use of nodular cast iron in ground transport industry, e.g., trains and automobiles, has brought growing scientific interest. The various applications of this material are due to the versatility of mechanical properties without adding alloy elements, making possible to achieve good results varying just the heat treatment. Due to its high fluidity, workpieces made of this material can be produced with final dimensions and shapes very close to the designed ones, making necessary just the use of finishing machining operations to get the final dimensions, more specifically those concerning the grinding process. To optimize cost production, machining processes became the focus of scientists and engineers. The grinding wheel can determine the success of an operation as its properties influence productivity and workpiece quality decisively. This work analyzes the grinding process of the ductile iron GGG-70 (average hardness of 270 HB) using two types of vitrified bonded CBN grinding wheels, which have as their only distinction the marked difference in friability of the abrasive grains. The performance of each grinding wheel will be analyzed taking into account the output parameters values obtained from surface roughness, average power, diametric wear of the grinding wheel, microstructure of the ground surfaces, and microhardness measures from the ground surface to the center of the workpiece. It was observed that the less friable wheel produced, regarding the average surface roughness, values of 0.27, 0.30, and 0.36 μm for the feed rates of 0.5, 1.0, and 1.5 mm/min, respectively, and, regarding the diametric wheel wear, produced values of 2.52, 2.99, and 4.01 μm for the same feed rates, respectively. On the other hand, when using the more friable wheel, average surface roughness values of 0.33, 0.44, and 0.64 μm and diametric wheel wear values of 3.21, 4.22, and 7.24 μm were obtained. In this way, the less friable wheel showed better results for all the conditions. Considering the feed rate order of 0.5, 1.0, and 1.5 mm/min, the improvement in surface roughness was about 18.18, 31.82, and 43.75%, respectively, and the reduction of the wheel wear was about 21.50, 29.15, and 44.61%. UNESP Saint-Gobain Surface Conditioning - Ceramic Materials UNESP FAPESP: 2015/10460-4

Made available in DSpace on 2018-11-26T17:54:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-07-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Among the alternatives to reduce the application of cutting fluid in machining industry, minimum quantity lubrication (MQL) technique has been promising, although it can impair cooling properties and the ability of the fluid to penetrate the cutting region. In order to further reduce the quantity of oil and to improve the characteristics of the cooling lubrication method, this work aims to compare the effect of MQL with different ratios of oil/water (1:1, 1:3, and 1:5) on the performance of plunge cylindrical grinding of alumina. Lubricating effect and effective penetration of fluid in the cutting zone are considered the most relevant factors. The lowest surface roughness value was obtained with the application of conventional flood cooling, followed by MQL 1:1. In comparison to conventional MQL technique, reduced surface roughness and grinding wheel wear could be obtained by applying MQL with water. Sao Paulo State Univ, Dept Mech Engn, Av Luiz Edmundo Carrijo Coube 14-01,Mailbox 473, BR-17033360 Bauru, SP, Brazil Univ Fed Sao Carlos, Dept Mech Engn, Rod Washington Luis Km 235, BR-13565905 Sao Carlos, SP, Brazil Sao Paulo State Univ, Dept Elect Engn, Av Luiz Edmundo Carrijo Coube 14-01,Mailbox 473, BR-17033360 Bauru, SP, Brazil Sao Paulo State Univ, Dept Mech Engn, Av Luiz Edmundo Carrijo Coube 14-01,Mailbox 473, BR-17033360 Bauru, SP, Brazil Sao Paulo State Univ, Dept Elect Engn, Av Luiz Edmundo Carrijo Coube 14-01,Mailbox 473, BR-17033360 Bauru, SP, Brazil FAPESP: 2015/09197-7 FAPESP: 2015/09868-9 FAPESP: 2017/03788-9

This work aims at determining the right moment to stop single-point dressing the grinding wheel in order to optimize the grinding process as a whole. Acoustic emission signals and signal processing tools are used as primary approach. An acoustic emission (AE) sensor was connected to a signal processing module. The AE sensor was attached to the dresser holder, which was specifically built to perform dressing tests. In this work there were three types of test where the edit parameters of each dressing test are: the passes number, the dressing speed, the width of action of the dresser, the dressing time and the sharpness. Artificial Neural Networks (ANNs) technique is employed to classify and predict the best moment for stopping the dressing operation. During the ANNs use, the results from Supervised Neural Networks and Unsupervised Neural Networks are compared.

Made available in DSpace on 2018-11-12T17:28:12Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-12-01. Added 1 bitstream(s) on 2018-11-12T17:36:17Z : No. of bitstreams: 1 S2448-167X2017000400429.pdf: 1093013 bytes, checksum: 437bbeec5578f9bf77e4243027d0800c (MD5) Abstract The coolant delivery technique known as Minimal Quantity Lubrication (MQL) has been employed in machining since the end of the 20th Century and has gained considerable evidence in the last years as a viable alternative to the use of the conventional coolant technique (flood). Due to the low oil flow rate delivered by the MQL technique in grinding operations, that generally varies from 20 to 240 ml / h in relation to near 600,000 ml / h flow rate of the conventional coolant technique, the MQL technique provides a reduced risk for human health and environmental damage associated with the use, maintenance and disposal of cutting fluids. In this context, this study was carried out to evaluate the application viability of the minimum quantity lubrication coolant technique under different flow rates in the plunge cylindrical grinding of ABNT 4340 steel with an aluminum oxide wheel. Three flow rates were tested: 30, 60 and 120 ml/h. Grinding trials with the conventional coolant delivery method were also tested for comparative purposes. The output variables used to assess the efficiency of the MQL technique in this work are: roughness, roundness and hardness of the workpiece. Grinding wheel wear and power consumption were also monitored. The results showed that, despite the higher values of roughness and roundness of the workpiece, as well as the grinding wheel wear, the values of these same parameters obtained after machining with the MQL technique were close to those obtained after machining with the conventional technique. No thermal damages and cracks on the machined surface, or even below the machined surface, were observed after grinding ABNT 4340 steel irrespective of the coolant-lubrication condition investigated. The results showed that the MQL with 120 ml/h can be an alternative coolant technique due to cleaner environment and lower consumption of fluid in grinding under the conditions investigated in this work. Universidade Estadual Paulista Júlio De Mesquita Filho Departamento de Engenharia Mecânica Faculdade de Tecnologia SENAI Londrina Departamento de Educação Universidade Federal de Uberlândia Faculdade de Engenharia Departamento Mecânica Universidade Estadual Paulista Júlio de Mesquita Filho Faculdade de Engenharia Departamento de Engenharia Elétrica Universidade Estadual Paulista Júlio De Mesquita Filho Faculdade de Engenharia Departamento de Engenharia Mecânica Universidade Estadual Paulista Júlio De Mesquita Filho Departamento de Engenharia Mecânica Universidade Estadual Paulista Júlio de Mesquita Filho Faculdade de Engenharia Departamento de Engenharia Elétrica Universidade Estadual Paulista Júlio De Mesquita Filho Faculdade de Engenharia Departamento de Engenharia Mecânica

Made available in DSpace on 2018-11-26T17:48:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-03-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) MQL technique is considered as a cleaner machining compared to the conventional coolant delivery one, thereby ensuring environmental sustainability and economic benefits. However, one of problems commonly reported when using the MQL technique is the wheel clogging phenomenon as a result of the inefficient chip removal from the cutting zone, then the chips lodge inside the pores of the grinding wheel, adversely affecting the quality and the finishing of the final product. In this context, this study was carried out to evaluate the performance of the minimum quantity lubrication coolant technique assisted with a wheel cleaning jet (MQL + WCJ) in plunge grinding of hardened steel. This cooling-lubrication technique was tested using the following flow rates: 30, 60, and 120 ml/h. Comparative tests were also carried out with the conventional coolant technique, as well as with the traditional MQL technique (without the wheel cleaning jet). The output variables used to assess the efficiency of the MQL + WCJ technique are roughness, roundness, workpiece microhardness, grinding wheel wear, and power consumption. The results showed that the machining with the MQL + WCJ technique outperformed the traditional MQL technique in all the output parameters investigated. Also, the efficiency of the MQL + WCJ technique increased with flow rate, thereby being an alternative coolant delivery technique in grinding due to cleaner environment, more sustainable and lower consumption of fluid compared to conventional coolant one. No thermal damages and cracks on the machined surface and sub-surfaces were observed after grinding AISI 4340 steel, irrespective of the technique. Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Sao Paulo, Brazil Univ Fed Uberlandia, Sch Mech Engn, Uberlandia, MG, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Sao Paulo, Brazil FAPESP: 2015/09197-7

Made available in DSpace on 2018-11-26T17:48:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-03-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) The application of minimum quantity of lubricant (MQL) in grinding process is a challenging task. Once the MQL is considered an environmentally friendly technique, its implementation in grinding process is interesting to achieve cleaner production. On the other hand, its use brings some problems to the process, such as intensification of grinding wheel clogging phenomenon and increase of cutting temperatures, which impairs on the attainment of a good surface quality, together with dimensional and geometrical accuracy. Looking for improving the MQL efficiency in grinding process, two eco-friendly techniques were found: the addition of water in the MQL and the wheel cleaning system with compressed air. The present research seeks to evaluate the improvement of MQL application in grinding using the combination of these techniques. Both techniques MQL + water and wheel cleaning system are innovative, since there are almost no articles in literature citing its use. The experiments were performed in an external cylindrical plunge grinding using a vitrified cubic boron nitrite (CBN) grinding wheel. The workpiece material was a quenched and tempered AISI 4340 steel. The cooling methods employed in the process were a conventional method (flood coolant), MQL + water (1:1, 1:3, 1:5 part of oil per parts of water), MQL + water + cleaning system (1:1, 1:3, 1:5 part of oil per parts of water), and MQL with and without cleaning system. Results were analyzed based on some workpiece parameters (roughness, roundness deviation, and microstructure) and on diametrical wheel wear and grinding power. The addition of water allied to cleaning system with compressed air provided the best results among those using the MQL technique, with results comparable to the conventional cooling method. Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil Univ Estadual Campinas, Dept Mech Engn, Campinas, SP, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil FAPESP: 2015/09868-9

Made available in DSpace on 2018-12-11T17:14:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-11-01 Researchers have evaluated a great number of monitoring techniques in order to control the surface condition of ground parts. Piezoelectric diaphragms of lead zirconate titanate are used in many fields, but these sensors are not common in the monitoring of the machining processes. This paper proposes a method for monitoring the workpiece surface condition (normal grinding and burn) by using a piezoelectric diaphragm and feature extraction techniques. A comparison is made with a conventional acoustic emission sensor, which is a traditional sensor in the monitoring of the machining processes. Grinding tests were performed in a surface-grinding machine with Society of Automotive Engineers (SAE) 1045 steel and cubic boron nitride (CBN) grinding wheel, where the signals were collected at 2 MHz. The workpieces were thoroughly analyzed through visual inspection, surface roughness and hardness measurements, and metallographic analyses. Study on the frequency content of both signals was carried out in order to select bands closely related to the workpiece surface condition. Digital filters were applied to the raw signals and features were extracted and analyzed. The root mean square values filtered in the selected bands for both sensors presented a better fitting to the linear regression, which is highly desirable for setting a threshold to detect burn and implementing into a monitoring system. Also, the basic damage index results show an excellent behavior for grinding burn monitoring for both sensors. The method was verified by using a different grinding wheel, which clearly shows its effectiveness and demonstrates the potential use of the low-cost piezoelectric diaphragm for grinding burn monitoring. Department of Electrical Engineering School of Engineering Bauru São Paulo State University (UNESP) Department of Mechanical Engineering School of Engineering São Paulo State University (UNESP) Department of Chemical Materials and Industrial Production Engineering University of Naples Federico II Department of Electrical Engineering School of Engineering Bauru São Paulo State University (UNESP) Department of Mechanical Engineering School of Engineering São Paulo State University (UNESP)

Made available in DSpace on 2020-12-10T19:40:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-11-13 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Grinding is one of the highest dimensional accuracy machining processes in the industry. To obtain the smallest form and geometrical workpiece deviation, it is necessary to add cutting fluids as the aim of ensuring the tolerances established for this process, by reducing the machining temperature, due to its cooling capacity, facilitating the cutting by its capacity lubricant. Currently, it is known that together with conventional fluid, there are problems related to environmental pollution and damage to the operator's health. Some techniques have come up to alleviate these problems; one of them is the minimum quantity lubricant (MQL) that has been outstanding for obtaining results close to flood application. This technique has stood out concerning the surface integrity and geometric and dimensional precision of the machined workpiece since a smaller quantity of cutting fluid is directed precisely in the cutting region. However, the reduced cooling capacity of MQL has promoted the researches to perfect this technique. In this way, this research aims to analyze the consequences of the water addition in this method to minimize the probability of thermal damages in the workpiece when applied in the grinding of SAE 52100 steel which is widely used in the manufacture of bearings, shafts, blades, and various other components where there is a need for high hardness and high abrasion resistance. The analysis of the output parameters evaluated the performance of the technique: surface roughness (Ra), roundness error, diametrical wheel wear, viscosity, cutting power, metallography, and microhardness. Beyond this, it evaluated the behavior of each lubri-refrigeration method concerning the ground surface through scanning electron and confocal microscopy, and it used optical microscopy to analyze of the grinding wheel cutting surface. The results of the water increment in the MQL were superior to those of the MQL (oil-pure) in almost all aspects, remaining inferior only in the cutting power. Also, the 1:5 dilution (oil-water) presented close and satisfactory results when compared to traditional cutting fluid (flood); it becomes an excellent alternative for insertion environmentally correct cutting fluids in today's industry. Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil Fed Inst Parana, Dept Control & Ind Proc, Jacarezinho Campus, Jacarezinho, Parana, Brazil Bauru Sao Paulo State Univ Julio de Mesquita Filh, Dept Elect Engn, Bauru Campus, Bauru, SP, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil Bauru Sao Paulo State Univ Julio de Mesquita Filh, Dept Elect Engn, Bauru Campus, Bauru, SP, Brazil FAPESP: 2016/23910-0 FAPESP: 2018/22661-2

Made available in DSpace on 2019-10-04T12:39:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-07-01 Made available in DSpace on 2019-10-04T12:39:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-07-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Nowadays, modern technology allows engineers to create tools with more adequate properties depending on the application. Currently, a lot of components require dimensional and geometric precision with tolerances increasingly tight. Grinding is the most suitable machining process in many cases and is currently applied in large scale in the machining business. Since it is a complex process due to its stochastic nature, there is a wide-open field of study and data collection to obtain the most efficient combination of tool/workpiece material depending on what is desired, always seeking improvements and optimization of the process. Besides this, a new parameter that can recently be considered to select the grinding wheel is the abrasive grains' friability level within cubic boron nitride (CBN) material. Since there is scarce information about the influence of this specific parameter in the performance of the wheel, this work aims to fill this gap. This work analyzes the cylindrical grinding of the AISI 4340 steel using two types of vitrified-bonded CBN grinding wheels. Their only significant distinction is the difference in the abrasive grains' friability. The performance of each wheel was analyzed taking into account the results obtained from the parameters' surface roughness, roundness error, micro hardness, acoustic emission, and average power. Regarding the average surface roughness, the more friable wheel produced values of 0.31, 0.40, 0.44, and 0.53 mu m, respectively, for the 0.25, 0.50, 0.75, and 1.00 mm/min feed rates. On the other hand, the average surface roughness values obtained from the workpieces ground with the less friable wheel were: 0.22, 0.29, 0.35, and 0.40 mu m, respectively, for the 0.25, 0.50, 0.75, and 1.00 mm/min feed rates. This means that when using the less friable abrasive grain, the surface roughness is better, which suggests that in the friability range analyzed, the use of a less friable wheel produces workpieces with better quality. Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Sao Paulo, Brazil Fed Univ Fluminense, Sch Mech Engn, Rio De Janeiro, Brazil St Gobain, Dept Ceram Mat, Surface Conditioning, Sao Paulo, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Sao Paulo, Brazil FAPESP: 2015/10460-4

Made available in DSpace on 2019-10-04T12:38:41Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-09-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) In the last years, many researchers have proposed improvements to the minimum quantity lubrication (MQL) technique, in order to increase its efficiency and make it a viable alternative to the conventional application of cutting fluids for a cleaner machining. Besides the lubri-cooling effect inherent to the MQL technique, the cleaning of grinding wheel is pursued, since its surface undergoes the clogging phenomenon resulting in decreasing of the process performance. The main objective of this study is to assess the influence of the auxiliary wheel cleaning jet (WCJ) in an attempt to reduce the wheel clogging phenomenon and increase lubri-cooling and machining efficiencies in the cylindrical external grinding of AISI 4340 steel under the application of the MQL technique using aluminum oxide grinding wheel. The MQL combined with cleaning jet was compared to both flood application (conventional) and MQL without WCJ (traditional). MQL grinding employed oil flow rates of 30, 60 and 120 mL/h in order to evaluate the effects of amount of grinding fluid in the assessment. The conventional and MQL + WCJ methods produced lower surface roughness and roundness deviation compared to the other methods used due to the fact that they kept the wheel sharpness longer. Moreover, conventional and MQL + WCJ methods increased G ratio and reduced tangential grinding forces and specific energy in comparison to traditional MQL. The MQL + WCJ method enabled the removal of part of chips adhered on the grinding wheel active surface (GWAS) when compared to the traditional MQL, reducing the wheel clogging, which is one of the reasons for loss of wheel sharpness. Tubular chip form occurred not only in MQL + WCJ grinding but also in traditional MQL grinding, although it is not mentioned in literature. Sao Paulo State Univ Julio de Mesquita Filho, FEB, Dept Mech Engn, Sao Paulo, Brazil Univ Estadual Campinas, Dept Mech Engn, Campinas, SP, Brazil Univ Sao Paulo, EESC, Sch Engn Sao Carlos, Sao Carlos, SP, Brazil Sao Paulo State Univ Julio de Mesquita Filho, FEB, Dept Elect Engn, Sao Paulo, Brazil Sao Paulo State Univ Julio de Mesquita Filho, FEB, Dept Mech Engn, Sao Paulo, Brazil Sao Paulo State Univ Julio de Mesquita Filho, FEB, Dept Elect Engn, Sao Paulo, Brazil FAPESP: PN 2015/09197-7

Made available in DSpace on 2019-10-04T12:35:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-01-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) New alternatives for monitoring the ceramic grinding process have been studied. Monitoring vibration signals is one of the most successful methods because some characteristics that describe the behaviour and influence of the process on ground parts are only noticeable by studying such signals. This study aims to monitor the finishing of advanced ceramics during the surface grinding process via digital processing of the vibration signals. Experimental tests were performed using a surface tangential grinding machine with a diamond grinding wheel and alumina (Al2O3) test specimens. The vibration signal was measured by an accelerometer and recorded by an oscilloscope at a 2 MHz sampling rate. The tests were conducted at different depths of cut for two workpiece speeds (v(w)) under mild and severe machining conditions. Confocal microscopy and surface roughness R-a measurements were performed after grinding each workpiece to classify the samples. Digital signal processing was performed to achieve feature extraction. A frequency range of 800 Hz-2 kHz was most strongly related to the post-grinding ceramic condition. A correlation was found between vibration and integrity of the ceramic workpiece because the vibration signal was proportional to the surface roughness for each cutting depth used. To support the conclusion presented, a statistical analysis through variance by analysis of variance was performed. Sao Paulo State Univ, Dept Elect Engn, Av Engn Luiz Edmundo C Coube 14-01, Bauru, Brazil Sao Paulo State Univ, Dept Mech Engn, Av Engn Luiz Edmundo C Coube 14-01, Bauru, Brazil Sao Paulo State Univ, Dept Elect Engn, Av Engn Luiz Edmundo C Coube 14-01, Bauru, Brazil Sao Paulo State Univ, Dept Mech Engn, Av Engn Luiz Edmundo C Coube 14-01, Bauru, Brazil CNPq: 306677/2013-0

Made available in DSpace on 2019-10-06T17:13:38Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-09-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) A new category of corrosion inhibitors has been formulated. It uses water to propagate and it has been generically referred as V-active VCI®. These inhibitors promote a greater lubricity and detergency effect, used as cutting fluids; it results in less diametrical grinding wheel wear and better workpiece finishing. It can also promote the corrosion protection of the workpiece and the machine tool since the referred substance creates a protective film on the metallic surfaces, eliminating protective oils application on the parts; thus, it permits the elimination of degreasing step, reducing the number of process steps, and minimizing the environmental impact. Furthermore, it has no risk to human’s health and it is biodegradable. This paper compares the performance of the cutting fluid with V-active VCI® to a synthetic standard fluid in grinding process of AISI 4340 steel using aluminum oxide (Al2O3) grinding wheel at three different feed rates (0.25, 0.50, and 0.75 mm/min). The comparison was carried out based on the surface roughness, roundness deviation, diametrical wheel wear, acoustic emission, optical microscopy, and microhardness. The results showed that the fluid with corrosion inhibitor kept stable as the feed rate increased, which evidence the high performance of the tested fluid in severe conditions. In addition, the fluid with corrosion inhibitor was superior in almost all evaluated variables; it was unexpected since the standard fluid is consolidated in industry. Department of Mechanical Engineering School of Engineering São Paulo State University (UNESP) Department of Mechanical Engineering Sao Carlos School of Engineering EESC/USP VCI Brasil, Rod. Marechal Rondon KM 334,3 Department of Electrical Engineering School of Engineering São Paulo State University Department of Mechanical Engineering School of Engineering São Paulo State University (UNESP) Department of Electrical Engineering School of Engineering São Paulo State University FAPESP: 2017/03788-9

RESUMO A retificação é um processo de alta geração de calor, portanto, com seu uso em larga escala, a pesquisa e desenvolvimento de novas técnicas de lubri-refrigeração se fazem necessários, visando respeitar as leis ambientais, preservar a saúde do operador e reduzir custos de produção. Deve-se, então, buscar soluções que mantenham os mesmos parâmetros de qualidade, acabamento e os mesmos efeitos tecnológicos. Um dos métodos propostos para este fim é o MQL (mínima quantidade de lubrificação), que utiliza uma mistura de ar com baixo fluxo de óleo a elevada pressão. O aço a ser utilizado como corpo de prova foi VP 50, muito usado na indústria em moldes para injeção de termoplásticos. O rebolo utilizado foi o de carbeto de silício verde, com ligante vitrificado. Apresentam boas características térmicas, estabilidade química elevada na retificação ferros fundidos, materiais não ferrosos e não metálicos. A análise dos resultados foi feita através avaliação das variáveis de saída do processo, tais como rugosidade, emissão acústica, circularidade, microscopia óptica (para verificação de dano térmico) e microdureza. Dentre os resultados evidenciados, a técnica MQL demonstrou ser superior ao método convencional apenas nos parâmetros de circularidade e desgaste diametral do rebolo, sendo que não houve alteração microestrutural em ambos os métodos de lubrificação. ABSTRACT Grinding is a high heat generation process that requires large amount of coolant, therefore, its use in large-scale lead to research and development of new lubri-cooling techniques to attend technical requirements, environmental laws, to preserve the health of operator and, whenever possible, to reduce production costs. Into this context, it is important to find solutions that maintain the same quality standards, finishing and the same technological effects. An alternative that has been used since the end of 20th. century is the MQL (minimum quantity lubrication) technique, which uses a mixture of air with low oil flow with medium pressure. The steel to be used as a specimen was VP50, widely used in industry for injection mold of thermoplastic. The grinding wheel used was green silicon carbide with vitrified binder that possess good thermal properties, high chemical stability and is recommended for grinding of ferrous and nonferrous materials. The output variables employed in this work were the surface roughness, roundness errors and microhardness. The acoustic emission signal and diametrical wear were also monitored. Analyses of the machined surfaces to evaluate the occurrence of thermal damages were also carried out via optical microscope. Results show that machining with the MQL technique outperformed the traditional coolant delivery method in terms of roundness and diametrical wear. No evidence of microstructural changes in the machined surfaces was observed after grinding with both lubri-coolant techniques.

Cognitive modeling of tool wear progress is employed to obtain a dependable trend of tool wear curves for optimal utilization of tool life and productivity improvement, while preserving the surface integrity of the ground parts. This paper describes a method to characterize the dresser wear condition utilizing vibration signals by applying a cognitive paradigm, such as Artificial Neural Networks (ANNs). Dressing tests with a single-point dresser were performed in a surface grinding machine and tool wear measurements taken along the experiments. The results show that ANN processing offers an effective method for the monitoring of grinding wheel wear based on vibration signal analysis.

Made available in DSpace on 2020-12-12T02:35:51Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-07-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Minimum Quantity of Lubricant (MQL) has been used in the grinding process to make the process eco-friendlier. On the other hand, it brings some technical problems to this process: the clogging phenomenon, i.e., chips adherence on the wheel cutting surface. Although this phenomenon yields widely known negative effects on productivity and workpiece quality, few studies exist about clogging in MQL grinding. Thus, this paper aims to explain the clogging formation and evaluate its effects on workpiece finishing and geometrical tolerances. External cylindrical plunge grinding tests in quenched and tempered AISI 4340 steel with CBN wheel, varying lubri-cooling conditions were carried out. Clogging affects the cutting ability of the grinding wheel and impacts on the chip formation. The addition of water in the MQL flow reduced the clogging occurrence in 40%, which corroborated to a reduction of 51% the surface roughness and 58% the roundness error. Sao Paulo State University – Unesp Department of Mechanical Engineering University of Campinas – UNICAMP School of Mechanical Engineering University of Sao Paulo – USP Department of Mechanical Engineering Sao Paulo State University – Unesp Department of Mechanical Engineering FAPESP: 2015-09868-9

Grinding is a finish manufacturing process for high precision parts. As the part has high value added at this stage, anomalies and defects are unacceptable. Self-excited vibration or just chatter is an undesirable and complex phenomenon that occurs in grinding, as it may impair the performance of ground parts due to the negative effects such as poor surface quality, intolerable inaccuracy, disproportionate tool wear, among others. This work goal is to present a method for chatter detection in surface grinding of SAE 1045 steel with aluminum oxide grinding wheel by using acceleration signals and digital signal processing techniques. Experimental tests were conducted in a surface grinding machine where a data acquisition system allowed for acquiring the acceleration signals at 2 MHz. The surfaces of the workpieces were visually inspected by means of high resolution images. The harmonic content of the signals along the grinding period was investigated by using the short-time Fourier transform with the purpose of relating the chatter occurrence to it. The results show that the frequency magnitudes of the signals change in time and frequency domain with specific patterns in the spectrogram as the chatter takes place, and they are related to the grinding wheel rotation and its harmonics.

Made available in DSpace on 2018-11-12T17:28:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-07-01. Added 1 bitstream(s) on 2018-11-12T17:36:17Z : No. of bitstreams: 1 S2448-167X2018000300391.pdf: 606543 bytes, checksum: eb1a40d51717749b9c4481f167314a6a (MD5) Abstract Usually, machining employs cooling methods to avoid high temperatures. In most cases, the cutting fluid is applied with high flow and low pressures. This technique consumes a large amount of cutting fluid that causes serious problems in the environment and in the health of the worker. An alternative to the conventional cooling method is the Minimum Quantity of Lubricant. The MQL attempts to minimize the consumption of cutting fluid, which this study is about, whereby the reduction provided by this MQL was 99.99%. This technique consumes only the necessary quantity of cutting fluid to create a thin film of lubricant on the cutting surface grinding wheel. The MQL aerosol is injected with high pressure in the contact zone, efficiently lubricating the grinding process. However, the cooling effect of MQL is not enough to dissipate all heat produced during the grinding process. This study analyzes the improvement in the cooling effect caused by the addition of water in the MQL. The tests were done using different concentrations of cutting fluid in water, e.g. 1:0, 1:1, 1:3, 1:5 (oil:water). The experiment occurred on the external cylindrical plunge grinding with a vitrified cubic boron nitrite (CBN) grinding wheel, serving as the workpiece, the AISI 4340 quenched and tempered steel. The analyzed outputs were: surface roughness, roundness deviation, acoustic emission and vibration.. The results improved with the addition of water in the cutting fluid used in the MQL technique. The comparison with the MQL conditions showed that the best condition was the fluid with more water concentration. Universidade Estadual Paulista Júlio de Mesquita Filho Engenharia Mecânica Departamento de Engenharia Mecânica Universidade Estadual Paulista Júlio de Mesquita Filho Departamento de Engenharia Mecânica Universidade Estadual Paulista Júlio de Mesquita Filho Engenharia Mecânica Departamento de Engenharia Mecânica Universidade Estadual Paulista Júlio de Mesquita Filho Departamento de Engenharia Mecânica

Made available in DSpace on 2018-12-11T17:35:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-04-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) The grinding process is situated at the end of the machining chain, where geometric and dimensional characteristics and high-quality surface are required. The constant use of cutting tool (grinding wheel) causes loss of its sharpness and clogging of the pores among the abrasive grains. In this context, the dressing operation is necessary to correct these and other problems related to its use in the process. Dressing is a reconditioning operation of the grinding wheel surface aiming at restoring the original condition and its efficiency. The objective of this study is to evaluate the surface regularity and dressing condition of the grinding wheel in the surface grinding process by means of digital signal processing of acoustic emission and fuzzy models. Tests were conducted by using synthetic diamond dressers in a surface grinding machine equipped with an aluminum oxide grinding wheel. The acoustic emission sensor was attached to the dresser holder. A frequency domain analysis was performed to choose the bands that best characterized the process. A frequency band of 25–40 kHz was used to calculate the ratio of power (ROP) statistic, and the mean and standard deviation values of the ROP were inputted to the fuzzy system. The results indicate that the fuzzy model was highly effective in diagnosing the surface conditions of the grinding wheel. Department of Electrical Engineering UNESP, Av. Eng. Luiz E. C. Coube, 14-01 Department of Mechanical Engineering UNESP, Av. Eng. Luiz E. C. Coube, 14-01 Department of Electrical Engineering UNESP, Av. Eng. Luiz E. C. Coube, 14-01 Department of Mechanical Engineering UNESP, Av. Eng. Luiz E. C. Coube, 14-01

Made available in DSpace on 2018-11-26T17:48:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-04-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Grinding is generally the first choice to provide combination of both superior surface finish and closer dimensional tolerances in a machined component. This process can be employed in manufacturing of continuous and interrupted surfaces. Crankshafts and engine piston rings are examples of ground precision mechanical components having interrupted surfaces. However, the specific literature about grinding of interrupted surfaces is still scarce. In this context, aiming to further contribute to the understanding of the behavior of surface integrity of interrupted surfaces during grinding, this paper presents an experimental investigation of interrupted surfaces ground with white aluminum oxide grinding wheel. Discs of AISI 4340 hardened steel with different number of grooves (2, 6, and 12) on the external surface were tested. Experiments with discs without interrupted surface were also carried out for comparisons. In addition to the number of grooves, three values of infeed rate (0.25, 0.50, and 0.75 mm/min) were used as input parameters. The output parameters investigated were the geometric errors (surface roughness and roundness) of the workpiece material as well as the diametric wheel wear. Analysis of variance (ANOVA) test was performed to verify any statistical difference among the output variables. Results showed that both surface finish and roundness of workpieces with interrupted surfaces were higher than those obtained for continuous surface. These parameters also increased with infeed rate up to 0.50 mm/min, whereas the grinding wheel wear was more sensitive to number of grooves and infeed rate. No thermal damages were observed on the machined workpieces under the conditions investigated. Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil Univ Fed Uberlandia, Sch Mech Engn, Uberlandia, MG, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Dept Mech Engn, Bauru Campus, Bauru, SP, Brazil FAPESP: 2013/04900-6