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Mg-Zn-Ca alloy is a promising candidate for orthopaedic implants such as bone plates and screws, as it has a similar mechanical strength and elastic modulus to bone, and it degrades in the body without causing toxicity or inflammation. Drilling studies are necessary to optimize the drilling process parameters, to evaluate the machinability and surface integrity of Mg-Zn-Ca alloy, and to ensure the effective and efficient drilling for various applications in the medical and engineering fields. The present experimental study emphasizes the influence of Ca content, biofriendly coolants and their combined effect with standard drill bits on the surface quality and axial thrust force in the drilling operation of Mg-Zn-Ca alloy. The drilling parameters such as cutting speed, feed rate, standard tools, bio-compatible coolants were optimized with respect to the amount of Ca in the Mg-Zn alloy. The axial thrust force and average surface roughness of drilled holes were considered as response of the experiments. The drilled surfaces were measured for average surface roughness in the transverse direction along the centre path of the drilled hole and a qualitative analysis was also carried out using advanced confocal microscope. The results revealed that the cutting speed among continuous factors significantly influenced the axial thrust force and average surface roughness. The effect of categorical factors was assessed using a regression based ranking method. The results of statistical analysis revealed that high speed steel, and vegetable oil offered improved surface quality, whereas the coconut oil showed low axial thrust force. The liquid nitrogen showed high value of axial thrust force and average surface roughness due to the brittleness induced by cryogenic coolant before drilling operation. [ABSTRACT FROM AUTHOR]

As a technique in artificial intelligence, a convolution neural network model has been utilized to extract average surface roughness from the geometric characteristics of a membrane image featuring micro- and nanostructures. For surface roughness measurement, e.g. atomic force microscopy and optical profiler, the previous methods have been performed to analyze a porous membrane surface on an interest of region with a few micrometers of the restricted area according to the depth resolution. However, an image from the scanning electron microscope, combined with the feature extraction process, provides clarity on surface roughness for multiple areas with various depth resolutions. Through image preprocessing, the geometric pattern is elucidated by amplifying the disparity in pixel intensity values between the bright and dark regions of the image. The geometric pattern of the binary image and magnitude spectrum confirmed the classification of the surface roughness of images in a categorical scatter plot. A group of cropped images from an original image is used to predict the logarithmic average surface roughness values. The model predicted 4.80 % MAPE for the test dataset. The method of extracting geometric patterns through a feature map-based CNN, combined with a statistical approach, suggests an indirect surface measurement. The process is achieved through a bundle of predicted output data, which helps reduce the randomness error of the structural characteristics. A novel feature extraction approach of CNN with statistical analysis is a valuable method for revealing hidden physical characteristics in surface geometries from irregular pixel patterns in an array of images.

Internal burnishing operation is a prominent solution to improve the hole quality. In this study, minimum quantity lubrication (MQL) system parameters, including the diameter of the nozzle (N), impingement angle (I), the pressure of the compressed air (P), the flow rate of the lubricant (L), and the distance between the nozzle and workpiece (D) are optimized for decreasing the total energy consumption (TE), average surface roughness (AR), and air quality indicator (AI) of the internal roller burnishing process. The predictive models of performance measures were developed using the adaptive neuro-based-fuzzy inference system (ANFIS) approach, while a novel model is developed to compute the total burnishing cost (BC). The neighborhood cultivation genetic algorithm (NCGA) and the VIKOR method were used to generate a set of prominent solutions and determine the best selection. The outcomes presented that the optimizing values of the N, I, P, L, and D are 1.0 mm, 35 deg., 0.3 MPa, 70 ml/h, and 10 mm, respectively. The TE, AI, AR, and BC are decreased by 3.1, 9.3, 20.6, and 7.9%, respectively, at the chosen point. The proposed performance measures could be utilized to precisely forecast the responses in the practical burnishing. The developed optimizing method combining the ANFIS, NCGA, and VIKOR could be effectively utilized to deal with complicated optimization issues for machining operations. The observed findings provided efficient information, which could help machine operators to select the optimal MQL system parameters and enhance the burnishing performances. [ABSTRACT FROM AUTHOR]

A novel approach utilizing triangle toolpath has been developed in this study to improve the surface finish of parts created by extrusion-based additive manufacturing (AM). During the extrusion-based AM process, poorly oriented surfaces can result in inferior surface quality, failing to meet the desired quality requirements for the final part. The inherent staircase effect in extrusion-based AM limits the part surface quality of built parts, resulting in a substandard surface finish. To overcome this limitation, a triangle-based machining toolpath approach has been introduced to remove staircases from all directions and enhance the average surface roughness of parts produced through extrusion-based AM. The combined impact of AM and machining parameters on the outcome was investigated using statistical analysis techniques. Experimental results and surface profile images have validated the effectiveness of the proposed approach in achieving an improved surface finish. [ABSTRACT FROM AUTHOR]

AISI 4340 hardened steel is usually used in axle shafts, main shafts, gear, and couplings. Using multi-layer physical vapor deposition a coated tool, an attempt was made to optimize the input variables on precise turning on hardened AISI 4340 grade steel. The cutting speed, feed rate, and depth of the cut were the applied process factors in the dry-cutting environment. Furthermore, surface roughness (Ra), flank wear (VBc), cutting temperature (T), and chip morphology were considered as technological responses. The Taguchi L27 standard orthogonal array with three levels and three factors was used in the experiment. Furthermore, scanning electron microscopy and energy dispersion spectroscopy were used to analyze tool wear and chip morphology characteristics. The relevance of the input process factors on the measured responses was determined using analysis of variance analysis. The feed rate was observed to have a dominant impact on the surface roughness in the trials. At an optimal parametric combination with 80 m/min cutting speed, 0.05 mm/rev feed rate, and 0.3 mm depth of cut obtained from the Taguchi-TOPSIS optimization method. The enhancement of the closeness coefficient was observed to be 0.2372. The generated second-order regression model was demonstrated to be of high significance. The strategy and outcomes of this research will help metal machining enterprises to augment manufacturing productivity when working with hardened steel. [ABSTRACT FROM AUTHOR]

Copyright of International Journal of Engineering Research & Development (IJERAD) is the property of International Journal of Engineering Research & Development and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As a result of the development of engineering technology, new opportunities and methods are constantly being developed to examine individual material structure changes, but most of these are impossible to implement on a low budget. Tests carried out with finite element simulations enable the optimization of machining processes and the reduction of experimental costs. The paper discusses the modelling of burnishing process that can effectively reduce surface roughness and the effect of burnishing force on average surface roughness. The machining is simulated using DEFORM-2D software, corresponding to the values of the experimental parameters (burnishing force, feed, speed) implemented in practice, allowing a comparative analysis of the material quality of low alloyed aluminium. [ABSTRACT FROM AUTHOR]

In recent years, cryogenic treatment has been applied to improve the performance of cutting tools. Improving the performance of cutting tools can improve the surface qualities of workpiece and reduce costs. Nickel-based superalloys are difficult to machine. It is necessary to improve the machinability properties of these hard-to-machine alloys and to increase the product quality. In this study, the effects of cryogenically treated physical vapor deposition-coated tools on the turning performance of nickel-based Hastelloy C22 superalloy were investigated. Deep cryogenic treatment (−145°C) and shallow cryogenic treatment (−80°C) were applied to the physical vapor deposition-coated tools. Experiments were carried out under dry conditions. The cutting parameters selected for the machining were cryogenically treated cutting tools, cutting speed, and feed rate. The deep cryogenic treatment had a favorable influence on the performance of the physical vapor deposition-coated carbide inserts. Thanks to the deep cryogenic treatment applied to the cutting tools, 99.5% and 19.7% improvement in surface roughness and cutting forces were achieved, respectively, compared to the untreated tool. The deep cryogenic treatment contributed more to the wear resistance of the tools than the shallow cryogenic treatment. A slight increase in the hardness and electrical conductivity of the tools was detected thanks to the cryogenic treatment. [ABSTRACT FROM AUTHOR]

In fused deposition modeling (FDM), the prediction and optimization of surface roughness distribution by varying the process parameters of the printing is required during the process planning stage. During this stage, the traditional screening design, such as fractional factorial design, is commonly used to identify the process parameters that have the most considerable effect on process outcomes. The screening design is followed by further experiments, including only essential process parameters to develop prediction models and identify the optimal process parameters. Recently developed custom design approaches such as I-optimal design and definitive screening design (DSD) eliminate the need for follow-up experiments by identifying the critical process parameters and optimum process conditions in a single experimental design. Therefore, the present study is intended to compare the performance of I-optimal design and DSD in terms of prediction and optimization of average surface roughness (Ra) of fused deposition modeling (FDM) printed parts from poly lactic acid (PLA). The following process parameters were considered to reduce the prediction error of Ra models: layer thickness, number of contours, infill density, raster angle, printing speed, extrusion temperature, bed temperature, and built orientation. The results revealed that regression models based on the I-optimal design are saturated and complex, with 38 terms (including eight main effects, twenty three interaction effect, and seven quadratic effects) in the final model. However, the DSD model has 12 model terms (including seven main effects, two interaction effects, and three quadratic effects), making it unsaturated and less complex compared to the I-optimal design. Both models have comparable prediction accuracy based on validation tests. Finally, Ra is optimized based on the desirability function. The results of the present study will add knowledge to the existing literature about the performance of I-optimal and DSD methods in predicting and optimizing responses. [ABSTRACT FROM AUTHOR]

The objective of this study is to optimize the fabrication factors of a consumer-grade fused filament fabrication (FFF) system. The input factors were nozzle temperature, bed temperature, printing speed, and layer thickness. The optimization aims to minimize average surface roughness (Ra) indicating the surface quality of benchmarks. In this study, Ra was measured at two positions, the bottom and top surface of benchmarks. For the fabrication, the material used was the Polylactic acid (PLA) filament. A response surface method (RSM), central composite design (CCD), was utilized to carry out the optimization. The analysis of variance (ANOVA) was calculated to explore the significant factors, interactions, quadratic effect, and lack of fit, while the regression analysis was performed to determine the prediction equation of Ra. The model adequacy checking was conducted to check whether the residual assumption still held. The total number of thirty benchmarks was fabricated and measured using a surface roughness tester. For the bottom surface, the analysis results indicated that there was the main effect from only one factor, printing speed. However, for the top surface, the ANOVA signified an interaction between the printing speed and layer thickness. The optimal setting of these factors was also recommended, while the empirical models of Ra at both surface positions were also presented. Finally, an extra benchmark was fabricated to validate the empirical model.

In general, Ti-6Al-4V alloys have been applied in recent metal cutting processes as an advantage of their immense strength concerning weight ratio at more corrosion resistance and temperature characteristics. It induces wide application in the automotive, nuclear, aerospace, biomedical, chemical, and naval industries. This recent research aims to establish the correlation between main input variables (cutting speed, axial feed rate, and depth of cut) and output characteristics (surface roughness, tool flank wear, and amplitude of vibration signal) in dry (no coolant) machining of Ti-6Al-4V alloy. The trials were conducted at variations of cutting speeds (75, 125, and 175 m/min), depth of cut (0.2, 0.4, 0.6 mm), and axial feed rate (0.1, 0.15, 0.2 mm/rev). The tool wear mechanisms were analyzed through scanning electron microscope. Also, the integrated multiple-output factors optimization method using a combined quality loss concept in the weighted principal component analysis coupled with the Taguchi analysis has been executed. With this, the optimal parameter setting has been found to be depth of cut (0.4 mm)–feed rate (0.1 mm/rev)–cutting speed (75 m/min). In this analysis, the optimized process input process variables determined will be definitely helpful to augment the performance characteristics of Ti-6Al-4V alloy in future research. [ABSTRACT FROM AUTHOR]

Copyright of Multidiszciplináris Tudományok is the property of University of Miskolc and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Machinability is expressed as the ease with which a material can undergo machining operations with gratifying surface finish and persistent material removal rate. In general, alumiAnium composites are observed to be difficult to machine due to infusion of hard reinforcement particles into metal matrix. In present study, machinability attributes of Al7075-T6/Eggshell/SiC/Al2O3composites (Al7075-T6 as matrix material infused with three reinforcement materials: eggshell particles with average particle size ~ 60 µm; wt. % 0.5, 1and 1.5, Silicon Carbide particles with average particle size ~ 65 µm; wt. % 1, 1.5 and 2, and Aluminium Oxide particles with averageparticle size ~90 µm; wt. % 1.5, 2 and 2.5,) synthesized through electromagnetic stir casting route, have been investigated with fixed machining parameters (Cutting speed: 6 m/min, Depth of cut: 1mm, Feed rate: 0.3 mm/second and Test duration: 30 seconds). With enhanced mechanical attributes, the machinability of synthesized aluminium composites was realized to remain uninfluenced in terms of proportionate material removal rate (material removal rate of specimen S8: 0.0040g/sec and of specimen S0: 0.0043g/sec) and comparable surface roughness (average surface roughness of specimen S8: 1.02 µm and of specimen S0: 1.15µm). Disposal of eggshells has been listed worldwide as one of the worst environmental problems, hence eggshell powder has been used as one of the reinforcement in order to synthesize ecodesigned hybrid aluminium composites. [ABSTRACT FROM AUTHOR]

It is agreed upon that labor's health conditions, as well as environmental pollutions, are broadly influenced by cutting fluids used in machining operations. In order to secure cleaner work parts and environment as well as reduced machining expenses, less fuel consumption is highly recommended. However, the quality of machined parts in the absence of fluid is considered a delicate subject. Under such conditions, the quality of machining process, as well as productivity, could be evaluated by different parameters and criteria including edge and surface quality, chip thickness, cutting force, and tool wear and life, which all seem to be highly influenced by many factors, including lubrication mode (dry and wet) and chip evacuation process. In order to take the benefits while avoiding the disadvantages of lubricated machining, novel lubrication method the so-called minimum quantity lubrication (MQL), which is micro lubrication near dry machining, is proposed. Review of literature denotes that under MQL condition, a low volume of information is available on the effects of mineral and bio-lubricants and various levels of flow rate on machining attributes, in principle average surface roughness (Ra) and chip thickness (hc) when machining aluminum alloys (AAs). To remedy the lack of knowledge determined, the effects of cutting conditions, in principle cutting speed, feed rate, lubricant, and various levels of flow rate on Ra and hc in MQL turning of AA 6061-T6 and AA 7076-T6, are presented. Therefore, three different experimental models, including multiplicative, 2-factor interactions (2FI), and linear models, were used in this study to assess the effects of cutting parameters on the machining outputs. According to experimental observations and despite the design models used, both Ra and hc are statistically significant responses and could be controlled by variation of the cutting parameters used. A strong relationship can be formulated between both responses and experimental parameters used. Although negligible, however, biodegradable cutting fluid with higher viscosity denoted better capability to improve the surface finish. The use of a higher flow rate also led to improved surface finish (up to 50%). It was observed that despite the material used, both flow rate and cutting fluid have insignificant effects on hc. [ABSTRACT FROM AUTHOR]

In this study, the effect of processing parameters on surface roughness and macro surface characteristics was analyzed during the machining of Ø30 mm and 300 mm aluminum alloy AA5083 abrasive water jets. As the processing parameters (up to 10 mm min−1, 15 mm min−1, 20 mm min−1 and 25 mm min−1), abrasive flow rate (50 g min−1, 150 g min−1, 250 g min−1 and 350 g min−1), the lathe chuck rotational speed (25 min−1, 50 min−1, 75 min−1 and 100 min−1) and the nozzle approach distance (2 mm, 5 mm, 8 mm and 11 mm) were used in experiments. In experimental studies, the pump pressure (360 MPa) was used as a constant, in the form of an abrasive Garnet (100 mesh), and the nozzle diameter as 0.76 mm. According to the findings, the best results in terms of surface roughness were obtained as a result of turning speed and abrasive flow rate. When the macro surface characteristics were examined, it was found that the lathe chuck rotational speed increased, the rate of nozzle progression was low, the rate of abrasive flow was high and the nozzle approach distance was lower and the smoother surfaces were obtained. [ABSTRACT FROM AUTHOR]

Cross-sectional profile and surface quality of micro-fins of a heat sink play a significant role in the transmission of heat from microelectronic and MEMS devices subjected to intense heating. Several processes are available for the fabrication of such pin-fins, Reverse micro electro discharge machining (RµEDM) among them is one of the most promising. A wide range of parameters associated with this process provides varying competence for surface roughness. An effectively modeled and simulated surface, thus, may serve as a database for an operator to study the effect of parameters for the desired surface. A single discharge model is developed to study the volume removal by each discharge pulse to achieve the goal. ANSYS finite element code is used to simulate the process to find the volume of the crater for further prediction of average surface roughness values. The model's predictions are compared with experimental results for verifying the approach and presented a good agreement with them. [ABSTRACT FROM AUTHOR]

In vitro cellular responses of osteoblast-like cells were studied on titanium surfaces with different surface morphologies. Surface profilometry was used to determine whether rough or smooth surfaces with regular or irregular morphologies can be produced by conventional fabrication techniques. Significantly higher levels of cellular attachment were found using rough, sandblasted surfaces with irregular morphologies. These results correlate with recent in vivo findings and suggest that implants should be prepared with roughened surfaces at bony contact areas. [ABSTRACT FROM AUTHOR]

This study investigates the use of nanopowder-mixed dielectric oil and temporary metallic coating on highly doped Si sample to achieve nanometric surface roughness using μ-WEDM operation. To achieve this, two different nanopowders were used in dielectric medium with two different temporary metallic coating in the workpiece. This is with Al and C with metallic coating of (gold) thickness 160 nm and 320 nm. Further, the discharge energy level was varied into two proximate stages (80 V/13 pF and 85 V/0.1 nF). The results show that nanopowder-assisted μ-WEDM process has improved the material removal rate (MRR) by ~ 44.5% (maximum). However, the spark gap (SG) has also been increased to a maximum of 60% than without nanopowder-assisted the μ-WEDM process. Further, it was found in our study that graphite (C) nanopowder usually generates lower spark gap as compared to aluminum (Al) nanopowder. It has also been observed that at specific μ-WEDM condition, coating thickness, and powder concentration C, Al can easily produce nanometric average surface roughness (ASR) (for C lowest ASR was 76 nm and for Al lowest ASR was 83 nm). From the findings, it can be understood that ASR can be improved maximum ~ 65% for C nanopowder and ~ 51% for Al nanopowder-assisted μ-wire electro-discharge machining as compared to conventional μ-WEDM of Si wafer. Machining stability and evenness of the machined slots were also improved by a significant margin when nanopowder-assisted μ-wire electro-discharge machining method was applied. [ABSTRACT FROM AUTHOR]

Titanium alloys are the primary candidates in several applications due to its promising characteristics, such as high strength to weight ratio, high yield strength, and high wear resistance. Despite its superior performance, some inherent properties, such as low thermal conductivity and high chemical reactivity lead to poor machinability and result in premature tool failure. In order to overcome the heat dissipation challenge during machining of titanium alloys, nano-cutting fluids are utilized as they offer higher observed thermal conductivity values compared to the base oil. The objective of this work is to investigate the effects of multi-walled-carbon nanotubes (MWCNTs) cutting fluid during cutting of Ti-6Al-4V. The investigations are carried out to study the induced surface quality under different cutting design variables including cutting speed, feed rate, and added nano-additive percentage (wt%). The novelty here lies on enhancing the MQL heat capacity using nanotubes-based fluid in order to improve Ti-6Al-4V machinability. Analysis of variance (ANOVA) has been implemented to study the effects of the studied design variables on the machining performance. It was found that 4 wt% MWCNTs nano-fluid decreases the surface roughness by 38% compared to the tests performed without nano-additives, while 2 wt% MWCNTs nano-fluids improve the surface quality by 50%. [ABSTRACT FROM AUTHOR]

Machining of metal matrix composites has always been challenges for manufacturing engineers due to the presence of hard and brittle reinforced particles. In this article, a new way of alternate application of electrical discharge grinding and abrasive grinding has been applied through the use of slotted grinding wheel. The developed machining process has been named as slotted electrical discharge abrasive grinding. The performances of slotted electrical discharge abrasive grinding process are tested on aluminum–silicon carbide–graphite (Al/SiC/Gr) metal matrix composite workpiece. The experiments were performed using one parameter at a time approach considering the effect of current, pulse on-time, pulse off-time, wheel speed and grit number on material removal rate and average surface roughness. It has been found that current ranges from 3 to 15 A and wheel speed ranges from 700 to 1300 r/min are more appropriate for machining of Al/SiC/Gr composite material within the ranges of selected parameters. [ABSTRACT FROM AUTHOR]

Additive Manufacturing (AM) is recently used to manufacture biomedical implants as the customized fabrication of the desired complex shapes is easily achievable with reduced manufacturing time and material waste. However, the poor surface quality of additively manufactured products is a major concern over biomaterials' functionality. Magnetorheological Fluid Assisted Finishing (MFAF) process is an advanced surface finishing process used to improve the workpiece surface quality without altering surface topography. Selective Laser Melting (SLM) is utilized in the presented study to fabricate biomaterials using SS316L powder, and surface quality is further enhanced through the MFAF process. However, average surface roughness (R a) only delivers the details regarding the average altitude of peaks and depth of valleys from the central line. Therefore, kurtosis (R k u) and skewness (R sk) analysis of the polished surface are also carried out to determine detailed surface characteristics. The bio-tribology analysis of the polished surface of the AM implant determines its sustainability inside the human body. Hence, a wear test utilizing the pin-on-disc process is performed on the finished surface to determine the efficiency of the polishing process during tribological contact of the biomaterials with the bone. Further, the improved surface roughness parameters (R a , R k u , and R sk) after the MFAF of AM implant's surface are also investigated with an optical profilometer and scanning electron microscope. The MFAF process produced a highly polished surface on the biomaterial and a final R a value of 32.46 nm is attained after polishing from its initial value of 8.32 μm with a decrease in wear rate (i.e., from 9.86 × 10−5 mm3/min to 0.46 × 10−5 mm3/min). The value of kurtosis less than three (i.e., 0.79) indicates that the flat peaks are generated on the surface irregularities after MFAF. Similarly, the negative skewness (i.e., Rsk = −0.28) represents that the number of peaks is less than the valleys. It indicates that the chances of wear out of the surface irregularities from the workpiece on their tribological contact are very low. • Surface characteristics improvement of Selective Laser Melted biomaterial (SS316L). • A mirror-like polished surface is achieved through Magnetorheological Fluid Assisted Finishing process on the biomaterial. • A final R a value of 32.46 nm is attained after polishing from its initial value of 8.32 μm. • The wear rate is reduced on the polished surface from 9.86 × 10−5 mm3/min to 0.47 × 10−5 mm3/min. [ABSTRACT FROM AUTHOR]

Background: Dental casting alloys play a prominent role in the restoration of the partial dentition. Casting alloys have to survive long term in the mouth and also have the combination of structure, molecules, wear resistance and biologic compatibility. According to ADA system casting alloys were divided into three groups (wt%); high noble, Noble and predominantly base metal alloys. Aim: To evaluate the mechanical properties such as tensile strength and surface roughness of the new and recast base metal (nickel-chromium) alloys. Materials and Methods: Recasting of the base metal alloys derived from sprue and button, to make it reusable has been done. A total of 200 test specimens were fabricated using specially fabricated jig of metal and divided into two groups- 100 specimens of new alloy and 100 specimens of recast alloys, which were tested for tensile strength on universal testing machine and surface roughness on surface roughness tester. Results: Tensile strength of new alloy showed no statistically significant difference (p-value>0.05) from recast alloy whereas new alloy had statistically significant surface roughness (Maximum and Average surface roughness) difference (p-value

This study analyzes the effects of machining parameters on the surface roughness and macro surface characteristics when machining Al-6082 T6 alloy of ∅30 and 240 mm in size using abrasive water jet (AWJ) turning processes. The material removal tests were conducted using a computer numerical control (CNC) abrasive jet cutting machine for different parameters of nozzle feed rate (10, 15, 20 and 25 mm·min −1 ), abrasive flow rate (50, 150, 250 and 350 g·min −1 ), spindle speed (25, 50, 75 and 100 min −1 ) and standoff distance (2, 5, 8 and 11 mm). Pump pressure at 350 MPa, abrasive type of Garnet and size of 120 Mesh, and nozzle diameter of 0.75 mm are kept constant throughout the experiments. When macro surface characteristics were analyzed, it was found that increased spindle speed, decreased nozzle feed rate, increased abrasive flow rate and lower standoff distance resulted in smoother surfaces. According to the findings of this study, best results were obtained when spindle speed and abrasive flow rate were increased. [ABSTRACT FROM AUTHOR]

Abrasive water-jet turning (AWJT) is one of these alternative methods and has gained an important status among others in a very short period of time. AWJT becomes prominent with its flexibility in cutting materials with almost any properties, with the elimination of thermal effects during the process, and with minimal stresses it imposes. It is widely preferred when heat-affected zones are to be avoided as it is a cold process. AWJT, on the other hand, is the replacement of a traditional cutter head of a turning testing apparatus with the AWJ in order to remove material turning the workpiece using a spindle testing apparatus while moving the nozzle on an axis with a specific distance from the workpiece. It is convenient to machine planar workpieces using the AWJ while it is harder to machine (turn) workpieces. However, there are scientific studies on the machinability of the planar workpieces, studies on the machinability of cylindrical materials are rarely found in the literature. Among the machining parameters for AWJT are nozzle feed rate, spindle speed, abrasive flow rate, pump pressure, abrasive size, and standoff distance. The studies available in the literature focus on the impact on Ra (μm), machining depth (mm), and material removal rate (mm min) as experiment outcomes. In this study, reviews of the research are available in the literature on the turning of workpieces using abrasive water jet. This study will also discuss the recommendations for the future research. [ABSTRACT FROM AUTHOR]

In this paper, we have studied terahertz (THz) pulse time delay of porous pharmaceutical microcrystalline compacts and also pharmaceutical tablets that contain indomethacin (painkiller) as an active pharmaceutical ingredient (API) and microcrystalline cellulose as the matrix of the tablet. The porosity of a pharmaceutical tablet is important because it affects the release of drug substance. In addition, surface roughness of the tablet has much importance regarding dissolution of the tablet and hence the rate of drug release. Here, we show, using a training set of tablets containing API and with a priori known tablet's quality parameters, that the effective refractive index (obtained from THz time delay data) of such porous tablets correlates with the average surface roughness of a tablet. Hence, THz pulse time delay measurement in the transmission mode provides information on both porosity and the average surface roughness of a compact. This is demonstrated for two different sets of pharmaceutical tablets having different porosity and average surface roughness values. [ABSTRACT FROM AUTHOR]

This article describes the experimental investigation related to creation of holes in aerospace titanium alloy workpiece using static electrode machining and electrical discharge drilling (EDD) process. Special attachment for holding and rotating the tool electrode was developed and installed on electrical discharge machining (EDM) machine by replacing the original conventional tool holder provided on die sinking EDM. The effect of input parameters such as gap current, pulse on-time, duty factor and RPM of tool electrode on output parameters for average hole circularity (Ca) and average surface roughness (Ra) have been studied. It is observed that the effect of rotating electrode machining has considerable influence on the output parameters over stationary electrode machining. The micro-graphs and photographs of few selected samples were taken by SEM and metallurgical microscope, which also commensurate with the findings of the study. [ABSTRACT FROM PUBLISHER]

Drilling of holes in difficult-to-cut aerospace materials with desired surface finish and accurate geometry is beyond the capability of conventional twist drills. Nonconventional machining methods which have the capabilities to offset the cutting difficulties of twist drills are currently being used for making holes in hard materials under the terminology of advanced machining processes (AMPs). Electrical discharge machining (EDM) is one such AMP which has been used in the present experiment for making holes in high nickel alloy with slight modification in sinking EDM machine. The concept of tool rotation is incorporated in sinking EDM machine and authors have termed it as electrical discharge drilling (EDD). The main objective of this experimental study is to study and analyze the impact of introduced tool rotation in EDD. Present experiment confirms that tool rotation has substantive effect on surface roughness (Ra) and average circularity (Ca) of the hole made by EDD process. Micrograph results of two samples of machined workpiece also substantiates with output results of introductory concept of tool rotation in EDM machine. [ABSTRACT FROM AUTHOR]

Material removal rate (MRR) and surface roughness (SR) have always been a big deal during any manufacturing process. Metal matrix composites (MMCs) can't be effectively machined by conventional grinding and process is found to be slow when machined by electrical discharge machining (EDM). Present work is an attempt for modeling of electrical discharge diamond grinding (EDDG) in surface grinding mode which is known as the surface-electrical discharge diamond grinding (S-EDDG) process. The technique used for modeling the process is artificial neural network (ANN) through traingdx training function. Experiments were carried out on newly developed and fabricated surface grinding setup for EDDG on a die sinking EDM machine for Al-10wt%SiC and Al-10wt%Al2O3composite workpiece. Prediction through modeling of S-EDDG process indicates that MRR increases as pulse current, wheel speed, workpiece speed, depth of cut increases, and decreases with increase in duty factor. The Raincreases with increase of current, duty factor, depth of cut, and workpiece speed, and decreases with increase in wheel speed. [ABSTRACT FROM PUBLISHER]

The objective of this study was to investigate the surface characteristics of an aluminum 6061-T6 alloy subjected to Nd:YAG pulsed-laser irradiation. The test specimens were prepared by a mechanical polishing process using diamond paste and emery polishing paper to obtain different levels of initial surface roughness. After ten pulsed-laser shots, the surface morphology was observed via optical microscopy (OM) and scanning electron microscopy (SEM). Nano-indentation hardness testing was also conducted on the irradiated surface. The diameter of the melted zone increased with surface roughness because of the multiple reflection and absorption of the laser beam. The relative absorbance was measured as a function of the diameter of the melted zone with varied surface roughness. [ABSTRACT FROM AUTHOR]

This article presents an investigation of the machining parameters design for electro-discharge diamond face grinding (EDDFG). The setup for EDDFG was developed, and experiments were conducted on tungsten carbide cobalt (WC-10wt%Co) composite workpiece. The input machining parameters used in the present study were wheel speed, current, pulse on time, and duty factor. The settings of machining parameters were determined by using Taguchi's robust design approach. The machining parameters were optimized with multiresponse characteristics of material removal rate (MRR), wheel wear rate (WWR), and average surface roughness (ASR). Multiresponse signal-to-noise (MSNR) ratio was applied to measure the performance characteristics deviating from the actual value. Analysis of variance (ANOVA) was employed to identify the level of importance of the machining parameters on the multiple performance characteristics considered. Finally, experimental confirmation was carried out to identify the effectiveness of this proposed method. [ABSTRACT FROM AUTHOR]

Electrodischarge face grinding (EDFG) process has been developed for machining of flat surfaces of materials that are difficult to machine by creating spark between face of disc shape rotating tool electrode and workpiece.The rotation of non-abrasive disc shape tool electrode about vertical axis (a new feature of face grinding) improves material removal rate (MRR) and average surface roughness (ASR) because of effective flushing of working gap. This paper presents the effect of input process parameters of EDFG, such as discharge current, pulse on-time and off-time, and wheel speed on MRR and ASR during machining of high carbon steel and high speed steel workpieces. An attempt has also been made to compare the results with those of stationary electrodes. [ABSTRACT FROM AUTHOR]

Knitting needles are the main elements for the knitting process and they are continuously in contact with fibers, yarns and contaminants existing in the structure of the yarns. In this study, the wear occurring inside latch needle hooks was examined empirically to explain how it is affected by the type of yarn and the machine parameters. The wear of the needle hook was represented numerically based on the technique of the comparison of local surface heights. Scanning electron microscopy (SEM) stereoscopy was used for the evaluation of the hook surfaces. The average surface roughness parameter (Ra) was utilized for evaluating the wear inside the needle hooks, depending on various machine parameters such as yarn tension, knitting speed, etc., and on various yarn properties such as fiber type and yarn type. The results of this study showed that SEM stereoscopy can be used to understand the wear mechanism of the surfaces of needles. Both the statistical analysis of Ra measurements and SEM images supported the results. [ABSTRACT FROM AUTHOR]

Abstract: Abrasive flow finishing (AFF) is used to deburr, polish or radius surfaces and edges by flowing a semisolid abrasive medium over the intended surface to be finished. Such finishing operations play a crucial role in manufacturing process of machine parts. The cost escalates sharply when the requirement is to achieve surface roughness values near nano levels. The need for finishing is to avoid power losses due to friction, increase the wear resistance and to provide a long serviceable life to the equipment. AFF is used in the industries especially in the case of finishing complex internal and external shapes. However, AFF is a time consuming process and any effort to reduce the process time even marginally saves production time and cost of the finished product. In the present study, an effort is made towards improving the performance of AFF process by providing rotary motion to the workpiece (R-AFF: rotational abrasive flow finishing). Preliminary experimental comparative study is done on AFF and R-AFF processes to compare their process performance in terms change in R a (ΔR a) and material removal. Later complete experimental study on R-AFF is conducted using central composite rotatable design and the responses are plotted using response surface methodology. The workpiece materials used in the present study are Al alloy, Al alloy/SiC (10%) and Al alloy/SiC (15%) metal matrix composites (MMCs). The results of R-AFF are encouraging. The present study shows that rotational speed of workpiece has significant effect on output responses (ΔR a). Indigenously developed semi solid abrasive laden medium is used in the present study. Overall, the experiments have shown that R-AFF has a very promising future for the industries in terms of better finishing. [Copyright &y& Elsevier]

Erosion testing and surface preparation are studied using a 3-axis Computer Numerical Control (CNC) abrasive water jetting (AWJ) apparatus. The effects of erosion time t, impingement angle α and pressure p on the erosion rate E, average surface roughness R[suba], and surface hardness Rockwell C Hardness (HRC) were investigated in detail. Compared with conventional grit blasting, AWJ can reduce grit embedment in the target material due to the action of the high-pressure water. AWJ also has the advantage of generating a higher average surface roughness R[suba] over water jetting (WJ) due to the action of abrasive particles. In addition, AWJ increases the surface hardness HRC of the substrate material. The obtained higher degree of average surface roughness is helpful for improving the bonding strength between the coating and the substrate material. The erosion testing and the surface preparation are numerically controlled by a 3-axis CNC system; therefore precise and detailed results for various operating parameters can be obtained. [ABSTRACT FROM AUTHOR]