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Background: Root caries and teeth sensitivity are the two most common clinical conditions resulting from poor oral hygiene and incorrect use of dental cleaning aids and methodology. Aim: This study is to evaluate the safe nonabrasive use of charcoal as dentifrice along with its adsorptive properties on salivary bacteria, yeast, and polysaccharides in biofilm matrix. Materials and Methods: The Mohs Scale of Mineral Hardness was used to evaluate abrasiveness of charcoal by investigating the scratches it produces on rubbing steel, copper, and nickel plates. The adsorptive ability of charcoal to bind bacteria was measured using the quantitative polymerase chain reaction. Efficiency to bind polysaccharides by charcoal was performed by the spectrophotometric analysis. Results: The Mohs hardness test showed that charcoal caused less scratches on nickel plates. As nickel plates have a lower hardness index than enamel, this indicates that charcoal might not be significantly abrasive to enamel. Some toothpaste caused scratches on the nickel plates. The benefits of adsorptive nature of charcoal in normal oral hygiene procedure exceed possible side effects by far. Activated charcoal can be used as a safe dentifrice if used in nanometer sized powder form causing minimum abrasion and it can still disturb biofilm formation by adsorbing microbes, biomolecules, acids, and therefore, offer protection to enamel and helps in the prevention of caries. Conclusion: Using finely powdered charcoal with “Gum and teeth rubbing with Index Finger, followed by Tongue cleaning” (GIFT) method is nonabrasive and so safe like other commercial toothbrushes and toothpastes. Further studies investigating the safe use of charcoal are recommended.

Miniature gears are used in the biomedical, automotive, and aerospace industries for advanced automatic transmission. Significantly few finishing processes can be utilized to finish miniature gears due to the narrow spacing between the miniature gear teeth profiles. In the present study, a novel uniform flow restrictor, an exact negative replica of the miniature gear teeth profiles, is designed and developed while using the rotational magnetorheological fluid-based finishing process. The effect of critical parameters on the process's performance has been studied through response surface methodology (RSM). The surface roughness and surface texture of the finished gear profiles with different magnetorheological fluids with and without using flow restrictors are compared for consistent and precise finishing. After finishing, it is observed that all manufacturing defects in SS316L miniature spur gear are entirely removed. Also, the ultrafine surface roughness of 23.9 nm (Ra) is achieved using a uniform flow restrictor at miniature gear teeth profiles. The forces responsible for finishing gear profiles are also simulated using Comsol® Multiphysics for understanding the controlling mechanism correctly. A mathematical model for material removal using abrasive grains on gear profiles is carried out to anticipate material dislodgement mechanism during finishing. [ABSTRACT FROM AUTHOR]

This work aims to examine the effect of two different abrasives: zirconium silicate and mullite with three different particle sizes (5, 44 and 149 µm) on the frictional characteristics of brake pads. Six brake pads were developed using these two abrasives with three different sizes. The effect of the abrasives towards fade, recovery and wear was investigated by carrying out a tribological test in a Chase tester following SAE J661 standards. Results indicated that brake pads with coarser particles generated good fade resistance and acceptable recovery rate. This effect was explained based on the formation of a stable friction film observed through the field emission scanning electron microscopy and testing the microhardness at the surface of the samples after dry sliding. However coarser particles exhibited poor wear resistance. In comparison, smaller abrasive particles exhibited poor friction stability with excellent wear resistance. Detailed examination of the wear surfaces was conducted to identify the possible wear mechanism. [ABSTRACT FROM AUTHOR]

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This research addresses the influence of the Abrasive Water Jet Machining (AWJM) process parameters on the Chicken Feather Fiber (CFF) composite. The CFF composite was prepared using the waste chicken feather by a compression molding process. The AWJM experiments were conducted with different process parameters of water pressure (p), standoff distance (d), and nozzle transfer speed (s) and investigated their impact on surface roughness. The process parameter optimization has also been carried out, for better surface quality. The better surface quality was obtained for the combination of 350 MPa of water pressure, 80 mm/min of nozzle transfer speed, and 3 mm standoff distance. The surface quality has been improved using the optimized process parameters during the AWJM of the CFF composite in the confirmation experiments. Prediction of surface roughness has also been carried out by Artificial Neural Networks (ANN) and Response Surface Methodology (RSM) techniques. The comparison of the predicted surface roughness results with the experimental results has also been carried out, and the predicted results were very close to the experimental valves it shows the efficiency of the results. [ABSTRACT FROM AUTHOR]

Surface finish is very much important in all the machining processes. Fillers were playing the important role in the surface quality during the machining process of hybrid composites. This work addresses the influence of different weight percentages (wt. %) of basalt and graphene filler on the Abrasive Water Jet Machining (AWJM) surface quality. Hybrid composites of Banana/ sisal were prepared with 3 wt. % and 6 wt. % of basalt and graphene filler and 3 wt. % of basalt and 1 wt. % of basalt and graphene hybrid fillers. The AWJM has been carried out and investigated the effect of fillers on surface quality. The enhanced results were obtained during the 6 wt. % of graphene filler addition with the banana /sisal hybrid composite. The predicted surface roughness of 2.42 µm was obtained for the optimum machining parameters such as 250 MPa of P, 100 mm/min of v, 3 mm of d. The improvement in surface quality was noticed in the hybrid filler composite. [ABSTRACT FROM AUTHOR]

Magnesium alloy is one of the most popular light material which was used in biomedical. Magnesium alloy is very light, resistant to corrosion and good biocompatible. However, magnesium alloy is flammable, so it is effortless to burn. This research investigated the wear mechanism at the edge rotary cutting tool. The cutting tool used in this experiment is carbide insert with a diameter of 16 mm. Pressured cooling air was used to reduce wear progression. The cutting parameters selected were workpiece speed at 80, 120 and 180 m/min, feed rate at 0.10, 0.15 and 0.20 mm/rev., tool speed at 25, 50 and 75 mm/min, and constant depth of cut at 0.3 mm. Tool wear and wear mechanism of the cutting tool were measured by using a microscope with particular magnification. Maximum wear on the carbide cutting tool was 0.449 mm, which was achieved at the end of tool life. Dominant wear mechanism occurred at the cutting tool was abrasive wear. Some scratches were observed at the edge of the tool as a result of hard particles. Another wear type that occurred was crater wear at the top area of the insert. The wear on the cutting tool was due to the excessive heat generated during the machining process, which was due to friction between the cutting tool and workpiece material.

The non-Newtonian fluid polishing is an advanced method that is applied to machining the complex surfaces. This method significantly improves the surface quality and mechanical properties of the material. In addition, it also reduces the concentrated stress at the root of the gear, so the fatigue resistance of the material is increased. The characteristics of shear thickening fluid are applied to machining the alloy steel SCM435 gears in this study. Firstly, the relationships between main machining parameters (distance D, velocity V, and inclination angle I) and responses (pressure and surface roughness of gear) is investigated in the polishing process. The effect of three machining parameters to the polishing process is carried out by conducting the simulation and experiment. The simulations results found that the pressure area is distributed throughout all the gear surfaces and maximum pressure value is achieved about 16.3 kPa with inclination angle of 26 degrees. In addition, experimental results indicated that the surface roughness of the gear surfaces can be reach 12 nm after 25 min polishing. Finally, the multi-responses optimization is utilized to optimize the pressures on the gear surfaces in machining process. The experimental results illustrated that the surface roughness is achieved the smallest at maximum pressure area. The best surface roughness of the gear surfaces can be reach 13 nm under optimal machining parameters such as the distance of 15 mm, velocity of 1.5 m/s and inclination angle of 32 degrees.

The steel presents wide field of application. Abrasive wear resistance of steel relies mainly on microstructure, hardness as well as on the abrasive material properties. Moreover, the selection of a resistant to abrasion grade of steel seems to be still a crucial and unsolved problem. Especially due to the fact that real operation conditions can be affected by the presence of different abrasive materials. The aim of this work was to determine the effect of different abrasive grit materials i.e. garnet, corundum and carborundum on the abrasive wear result of a commonly used in industry practice steels i.e. S235, S355, C45, AISI 304 and Hardox 500. The microstructure of the steel was investigated using light optical microscopy. Moreover, hardness was measured with Vickers hardness tester. Additionally, the size and morphology of abrasive materials were characterized. The abrasion tests were conducted with the usage of T-07 tribotester (dry sand rubber wheel). The results demonstrate that the hardness and structure of steels and hardness of abrasive grids influenced the wear results. The abrasive wear behavior of steels was dominated by microscratching and microcutting wear mechanisms. The highest mass loss was obtained respectively for garnet, corundum, and carborundum. The usage of various abrasives results in different abrasion resistance for each tested steel grade. The austenitic stainless steel AISI 304 presents outstanding abrasive wear resistance while usage of corundum and Hardox 500 while using a garnet as abrasive material. C45 carbon steel was less resistant than AISI 304 for all three examined abrasives. The lowest resistance to wear in garnet and carborundum was obtained for ferritic-perlitic carbon steels S235JR and S355J2 and in corundum for Hardox 500 which presents tempered martensitic structure.

Electroless nickel plating with a nanofinished surface is used in space mirrors, automobile parts, aircraft components, optical instruments, and electronic equipment. Finishing of these components using conventional finishing techniques is limited due to size, shape, material, and process constraints. This work reports the nanofinishing of electroless nickel-plated surfaces using a magnetorheological finishing process where the surfaces are pre-treated with chemicals. The chemicals used in this work are hydrogen peroxide (H2O2) and hydrofluoric acid (HF). The effect of exposure time and concentration on the microhardness and roughness is studied to understand the surface chemistry after chemical treatment. The hydrogen peroxide forms a passivated layer, and it helps in easy material removal. Hydrofluoric acid improves surface quality and also helps in the removal of contaminants. The finished surface is characterized to understand the effect of chemical treatment on the finishing rate and surface topography. Normal and tangential forces are mainly affected by the hardness and surface condition after the chemical treatment. The best combination of parameters (chemical treatment with 1% HF for 30 min) was obtained and finishing was carried out to obtain a nanofinished surface with its areal surface roughness (Sa) reduced to 10 nm.

Optimizing the retaining ring structure can improve the quality of Chemical Mechanical Polishing (CMP). This study establishes a two-dimensional Computational Fluid Dynamics-Discrete Element Method (CFD-DEM) model, while the model is validated by experiments. The results graphically demonstrate the influence of the retaining ring groove design on the motion of the slurry abrasive particles. The size of the retaining ring groove appears to have a threshold value, above which the abrasives start to have significant distribution in the wafer region. As the groove size continues to increase, the number of abrasives entering the ring increases abruptly and oscillates at specific nodes. The abrasive transfer rate increases with the number of grooves in the early stage but reaches a limit at a certain number of grooves. Meanwhile, the retaining ring position affects the transfer of the abrasives. This study provides a base for optimizing the design of retaining rings.

Issues related to the study of wear resistance, strength, and other material characteristics of parts of tillage machinery are addressed. The importance of improving the heavy-duty tool of domestic tillage machines is evaluated. Chemical compositions and mechanical properties of steels for tools of agricultural machines of leading European manufacturers are given. New grades of steel for high-strength rolled products have been developed. Comparative results of laboratory bench tests for wear resistance of commercial and prototype domestic and foreign grades of rolled steel and powder hard-alloy coatings are presented. An effective technology for hard-facing of wearable parts of tillage machinery is substantiated and analyzed. Verification comparison performance and life-cycle tests of tools manufactured using new materials and facing technology were carried out. The life of the prototype tools was increased by a factor of 2.8 to 3.8. The market potential of using new materials science and technology developments in Russian agricultural production is assessed. [ABSTRACT FROM AUTHOR]

We developed a method of measuring microscopic ζ potential (ZP) from force vs distance (FD) curves observed by atomic force microscope (AFM). ZP in microscopic regions on wafer surfaces may be one of the most important design guides of chemical mechanical polishing slurries applicable to ultrafine patterned wafers, while ZP is generally observed as an average information for a wide area. Our method is based on the linear correlation between jump-in loads in FD curves observed by the AFM for the blanket wafers (SiO2, SiN and poly-Si) in water systems and ZP of each wafer surface measured by the flow potential method. In the applications of our AFM-based measurement method, material-dependency of ZP on the SiO2/SiN patterned wafer surface and an additive material in a slurry (anionic polymer) adsorbing selectively on the SiN surface of the SiO2/SiN patterned wafer were observed. [ABSTRACT FROM AUTHOR]

Abrasive water jet (AWJ), which is a non-traditional machining method, is more widely used today. Various materials such as metals, ceramics, polymers, and composites can be easily machined with AWJ. In this study, cutting of St37 steel plates in stacked form with AWJ was investigated. The experiments were carried out according to the general full factorial design. Experimental parameters were inter-stack distance, traverse speed, and abrasive mass flow rate also each of these parameters was chosen at three levels. Surface roughness and kerf widths were examined to determine the cutting performance. Analysis of variance (ANOVA) of all outputs was provided and thus the effects of experimental parameters and their levels on cutting performance were found. The most effective parameters for surface roughness and kerf width in almost all conditions were abrasive mass flow rate and inter-stack distance, respectively. In addition, a concept for multi-simultaneous cutting was developed with mathematical differences of surface roughness and kerf taper angle. Thus, optimum levels of experimental parameters were found for minimum mathematical differences. [ABSTRACT FROM AUTHOR]

Surface quality is an important output measure in all the machining processes. In this research, cotton and viscose fabrics were used as a reinforcement, graphene was used as a filler (1.5, 3, 4.5 weight percentage (wt. %)) for the development of hybrid composite using compression molding process with hand layup techniques. The machinability of the prepared hybrid composite was studied using the Abrasive Water Jet Machining (AWJM) process. The effect on AWJM input parameters of water pressure (P), nozzle transverse speed (v), and abrasive flow rate (m) over the surface roughness (Ra) have also been studied using Design of Experiments (DoE) with Taguchi analysis. A better surface quality was obtained for the addition of 4.5 wt. % of graphene filler in the hybrid composite with the optimized AWJM process parameters of 250 MPa of P, 60 mm/min of v, and 200 g/min of m. [ABSTRACT FROM AUTHOR]

In this paper, waste glass powder (GP) is selected as a sustainable abrasive to replace pure silica minerals. XRF analysis to determine the content of glass waste. Composite specimens have volume fraction ratios of 0%, 2%, and 4% GP evaluated with TGA, Pin on Disc friction test, and Hardness Rockwell type R. Scanning electron micrograph (SEM) observe the formation of abrasion and surface wear of the specimen. The results of the X-ray fluorescence (XRF) glass powder waste obtained that the main content of silicon dioxide (SiO2) was 65.58%. Thermogravimetry (TG) showed that the thermal resistance of the composite from the addition of glass powder increased. Glass powder as an abrasive shown that increase the coefficient of friction brake friction materials. The presence of glass powder increases the hardness of the composite, and the coefficient of wear rate of the composite decreases. [ABSTRACT FROM AUTHOR]

Using an atomic force microscope, a nanoscale wear characterization method has been applied to a commercial steel substrate AISI 52100, a common bearing material. Two wear mechanisms were observed by the presented method: atom attrition and elastoplastic ploughing. It is shown that not only friction can be used to classify the difference between these two mechanisms, but also the 'degree of wear'. Archard's Law of adhesion shows good conformity to experimental data at the nanoscale for the elastoplastic ploughing mechanism. However, there is a distinct discontinuity between the two identified mechanisms of wear and their relation to the load and the removed volume. The length-scale effect of the material's hardness property plays an integral role in the relationship between the 'degree of wear' and load. The transition between wear mechanisms is hardness-dependent, as below a load threshold limited plastic deformation in the form of pile up is exhibited. It is revealed that the presented method can be used as a rapid wear characterization technique, but additional work is necessary to project individual asperity interaction observations to macroscale contacts. [ABSTRACT FROM AUTHOR]

The wear resistance of materials is crucial in mechanical component design, but there has been limited research on the tribological behavior of WC-reinforced high entropy alloy(HEA) to date. Therefore, this study used fast hot pressing sintering to fabricate WC/AlCoCrFeNi 2.1 metal matrix composites (MMCs). It was observed that: 1. The HEAs matrix had a biphase eutectic structure with FCC and BCC phases, while the interfacial layer consisted of M 7 C 3 and M 23 C 6 (M=Cr, W). 2. MMCs showed proportional increases in microhardness, nanoindentation and wear resistance with reinforced particle addition. 3. During frictional processes, an oxide film formed providing material protection, enhancing stability and reducing friction-induced losses. Adhesive wear, abrasive wear, and three-body abrasion were identified as primary types of observed wear. • The WC/AlCoCrFeNi 2.1 composites were prepared by FHPS with good interfacial bonding. • M 23 C 6 and M 7 C 3 phases (where M=Cr, W) precipitate at the interface. • The presence of an oxide film greatly improves friction stability. • The main types of wear include adhesive, abrasive, and three-body abrasion. [ABSTRACT FROM AUTHOR]

This paper addresses the concept of the expert system for abrasive waterjet machining. For optimization of abrasive waterjet machining, computer based concurrent engineering environment is used. The design specification is acquired through a feature based approach. The expert system links with feature base library. The expert system links with material database which holds attributes of more than 20 type of materials. It also links with abrasive data base which hold attributes of 8 types of abrasive, and also 4 type and size of machine. expert system also links with machine database which hold machine parameters. For each design feature, the expert system provides information needed for optimization of design and manufacturing. The expert system can be used as an advisory system for optimization of design and manufacturing. It can be used as a teaching program for new abrasive waterjet machining operators. For each design feature, the expert system provides information such as machining cycle time and cost and cutting rate. By changing machine parameters, we can optimize machining cycle time and cost and cutting rate. Comparison results of the expert system and experimental CNC Abrasive waterjet results for different design feature shows that machining time and cost of expert system is 10% less than experimental.

The mode and parameters of applying an ion-plasma coating to the surface of the working bodies are established. The thickness of the ion-plasma coating on the surface of the excavating parts is specified. It is found that the samples with the thickness of the ion-plasma coating of 4 μm have the greatest wear resistance. The metallographic characteristics of the material of the knives with the ion-plasma coating applied to their surface are determined.

Abstract This study compares micro-abrasive wear in two kinds of grey cast iron. Classical lamellar cast iron with fully pearlitic matrix (FGL1) and lamellar micro-alloyed cast iron with phosphorus and boron (FGL2) are used. FGL2 has a fully pearlitic matrix reinforced by the hard phosphorus eutectic phase. The microstructures of these two types of iron are mechanically characterized using nanoindentation tests. Vickers microindentation and microscratch tests are also performed on these iron samples. The indent and scratch images obtained via scanning electron microscopy were used to compare the scratch damage to the two kinds of iron. The friction coefficient is discussed in terms of applied load, indenter attack angle, and scratch damage. Nanoindentation tests show an improvement in graphite’s mechanical properties and an increase in the matrix hardness of the FGL2, relatively to FGL1. The same damage forms for both microindentation and microscratch testing were observed for the two iron samples. However, cracking of the hard phase is observed in FGL2. The results show that the scratching of the micro-alloyed iron (FGL2) leads to less matrix damage and to an extended microploughing wear mechanism. However, at low normal load, the reinforcement of the matrix can increase the friction coefficient.

The use of carbon fiber-reinforced composites is increasing today since they have an excellent weight-to-mechanical properties ratio. Traditional machining of this material is difficult. Abrasive water jet machining (AWJM) is an advanced non-traditional material removal process that can machine hard-to-cut materials. The process is widely used in aerospace, marine, and automotive industries. However, it encounters several challenges when cutting carbon fiber reinforced polymers (CFRP). The present work aims to study the characteristics of AWJM of CFRP laminates. Detailed experimental investigations are conducted to explore the effect of traverse feed and standoff distance (SOD) on top kerf width, bottom kerf width, kerf angle, profile area, volumetric removal rate, and the average surface roughness, and jet deviation factor. Repeatability tests are also used to assess the kerf dimensional accuracy and surface roughness tolerance achieved by AWJM of CFRP laminates. Results showed that the surface roughness increases along with the cut thickness, especially at large traverse feed and SOD. Both the kerf taper angle and the volumetric removal rate increase with traverse feed and SOD. [ABSTRACT FROM AUTHOR]

As the only cold high-energy beam machining technology, abrasive water jet cutting has a lot of unique advantages to process a large variety of materials. The main factor restricting its development and application refers to its high processing cost. Abrasive consumption is considered as one of the main costs. Abrasive recycling is an effective way for reducing the cost. In addition, it is also beneficial to environmental protection. Abrasive suspension water jet (ASJ) is more suitable for abrasive recycling than traditional abrasive water jet (AWJ) because ASJ does not use dry abrasives. Based on the idea of strive for the recycling process simple and effective, the abrasive recycling of ASJ was studied in this work. It is found that the recycled abrasives with only big particle impurity being sieved out still have strong cutting ability. An simplified abrasive recovery scheme of ASJ cutting system has been proved to be feasible. With 30% of recharge in each cycle, the abrasive can be fully utilized and its cutting performance can remain basically the same in every reuse cycle of continuously recycling process. The abrasives between 90 and 180 μm are optimal abrasives for the cutting surface roughness, compared with the larger size abrasives; the smaller size abrasives have more negative influence on the surface roughness, which should be concerned in the recycling process. [ABSTRACT FROM AUTHOR]

The chip thickness is often used to characterize abrasive processes, particularly grinding. Unfortunately, because of the seemingly random nature of the geometrically undefined cutting points and difficulty in estimating the cutting-point density, chip thickness is notoriously difficult to quantify. Recently, the dimensionless Aggressiveness number has gained popularity because it circumvents the need to quantify the wheel topography and is applicable to any geometry in abrasive contact. This paper shows how the concept of dimensionless Aggressiveness number applies to the most common abrasive geometries and how it can be used to achieve practical results in a variety of applications. [ABSTRACT FROM AUTHOR]

It is known that there are some grinding issues for difficult-to-machine materials, such as adhesion of the grinding wheel, grinding burns, and poor surface quality. In this work, a novel abrasive tool which was based on the principle of liquid body armor was developed with flexible composite to improve the grinding performance. During grinding, particles in the abrasive tool will produce a "hydro-cluster effects" to remove the micro convex of the workpiece surface in a high-shear and low-pressure manner. Rheological measurement of prepared shear thickening fluid (STF) and shear thickening abrasive fluid (STAF) showed that the prepared STF and STAF possessed superior shear thickening properties. In addition, the grinding experiments were carried out to investigate the performance of the novel abrasive tool. Surface roughness of the Inconel718 workpiece decreased from Ra 1.55 μm to Ra 0.38 μm within 90 min. The original pretreatment marks were completely eliminated and the better surface finish was achieved. The surface quality of Inconel718 was greatly improved after grinding. Experimental results verified the effectiveness of the novel high-shear and low-pressure abrasive tool. This work is quite potential to provide an alternative new abrasive tool for the grinding of difficult-to-machine materials in manufacturing industries. [ABSTRACT FROM AUTHOR]

This article presents results of studying changes in the parameters of the vibration that occurs when a very hard composite material slides over a monolithic abrasive depending on the loading conditions and the materials of which the contacting elements are made. The vibration parameters are measured depending on the applied axial load, the relative displacement rate, and the material of the mandrel that holds the carbide element. The force induced by the vibration in the friction zone and its effect on the destruction characteristics of the abrasive are assessed. The influence of the vibration parameters on the energy distribution between the thermal and mechanical components under friction is shown. [ABSTRACT FROM AUTHOR]

Background. Water with a powder material is used as a working tool for hydroabrasive treatment. The quality of treatment and the service life of the equipment depends on the surface’s characteristics and the shape of the abrasive material’s particles, which is subject to a number of significant requirements. The cost of materials is quite high. The purpose of the work is to establish the possibility of reuse of abrasive material. Materials and methods. The main machining medium in experiment was the abrasive GMA 80 MESH TR (technical requirements) 3986-00176245879–2011 with the grain size of the main fraction 0.8 mm. Work piece was 20 mm thick sheet of aluminum alloy D16 State Standart 17232-99. The computer simulation program “Kompas 3D” was used for ASCON. Results. During hydroabrasive treatment, the radii of the grain protrusions, which are the main characteristic of the profile’s abrasive ability, significantly change. This leads to a reduction in their cutting capacity and the need to correct the hydroabrasive cutting technology to ensure the required cutting quality. However, when the grains are destroyed, new edges with different geometric characteristics are formed, which creates prerequisites for maintaining the grain’s performance. Conclusions. Changes in the parameters of abrasive grains in powder for hydroabrasive treatment after a working cycle are analyzed to determine the possibility of its reuse. The theoretical prerequisites for the change in the characteristics of the cut surfaces when reusing grain are stated

Machining of high strength and shock-absorbent Metal Fiber Laminate (MFL) becomes inevitable to attain the geometric shape and size, as to validate the functionality in various impact protection environments. A class of titanium metal laminate alternatively interleaved with high strength basalt and shock absorbing flax fibers have been machined with an abrasive water jet method. Machining experiment trials with WJP-water jet pressure, TS-traverse speed, SOD-stand-off distance, and AMFR-abrasive flow rate and parametric optimization on quality factors of surface roughness (Ra) and kerf ratio (KR) were done using a Central Composite Design (CCD)-Response Surface Methodology (RSM). Experimental investigation reveals that the surface roughness and kerf ratio significantly decreased by 27.59% and 9.16% as water jet pressure was increased to peak value. Similarly, abrasive mass flow rate raised to its higher value, the Ra and KR slightly decreased by a margin of 6.5% and 2.5%. However, a reverse effect on surface roughness and kerf ratio was observed as an increase of SOD and TS. Surface topology analysis reveals that the material removal mechanism of the Ti sheet is shear plastic deformation with plowing marks, that of basalt fiber is brittle fracture with micro-chipping, and that of flax fiber is bulk machining. [ABSTRACT FROM AUTHOR]

Background: to evaluate the effect of different dentifrices on the surface roughness of two composite resins (nanofilled-based and nanoceramic – based composite resins). Materials and methods: Forty specimens (diameter 12 mm and height of 2mm) prepared from different composite resin materials: Z350 (nanofilled composite, and Ceram-X (nanoceramic) .they were subjected to brushing simulation equivalent to the period of 1 year. The groups assessed were a control group brushed with distilled water (G1), Opalescence whitening toothpasteR (G2), Colgate sensitive pro-relief (G3) and Biomed Charcoal Toothpaste (G4). The initial and final roughness of each group was tested by surface roughness tester. The results were statistically analyzed using ANOVA and Tueky test at 0.05 significance level. Results: the surface roughness of the two tested composites brushed with the tested dentifrices was statistically higher than the roughness found in control group. Comparison among the three types of dentifrices showed that there was a statistically high significant difference in the surface roughness among all subgroups. Charcoal Toothpaste showed the highest surface roughness increase. Conclusion: Whitening dentifrices increase the surface roughness of dental composite thereby compromising its durability. Changes in composite depended on the material itself and the dentifrices used. [ABSTRACT FROM AUTHOR]

Abrasive Water jet cutting process fits in the category of unconventional dimensional processing technologies, based on the principle of erosion with complex fluid environments, kinetically activated. Currently, there are multiple researches for process optimization, especially taking into consideration the economic criteria, due to relatively higher costs present in the case of abrasive waterjet cutting. The paper presents a synthesis of a study started from research within the National R & D Institute for Welding and Material Testing - ISIM TIMIŞOARA, especially in the direction of increasing the efficiency of using the abrasive material associated with this cutting process. Several patented results regarding the recycling of used abrasive material in other fields are presented, as well as prospects for further research by studying other methods aimed at reducing costs without reducing the level of quality for abrasive water-jet cuts.

Fluoride and abrasives in toothpastes may cause corrosion and deterioration of the titanium used for implants and other prostheses. The purpose of this study was to investigate how the presence or absence and types of fluoride and abrasives affected the titanium surface texture. Brushing with toothpastes was performed on pure-titanium discs using an abrasive testing machine. Unprocessed titanium discs without brushing were used as control samples. Surface roughness, color, and gloss of titanium were measured and the differences compared with the control were analyzed. Additionally, titanium surfaces and abrasives in toothpastes were observed using a scanning electron microscope to compare the surface texture of each sample. Some toothpastes (abrasive+) significantly increased the difference in surface roughness, color, and gloss, compared with ultrapure water. Toothpaste (fluoride+/abrasive+) that had many polygonal abrasive particles led to the largest color differences and exhibited notable scratches and a larger number of contaminant- or corrosion-like black spots. In contrast, brushing with toothpaste without fluoride or abrasives (fluoride−/abrasive−) caused little change to the titanium surface. These results suggest that both fluoride and abrasives in toothpaste used for brushing may be factors that affect surface texture and corrosion resistance of titanium.

Reduction of non-exhaust airborne particulate matter (PM), leading to adverse effects in respiratory system, is an urgent task. In this work, we evaluated the impact of raw materials in friction materials on PM emission due to brake wear for passenger vehicle. Time- and temperature-dependent measurements using dynamometer were made for low-steel friction materials with varied abrasives and lubricant(graphite). The brake emission factor (BEF) for graphite of varied sizes ranged from 6.48 to 7.23 mg/km/vehicle. The number concentration indicates that smaller graphite (10 μm) produces more nano-sized particles than larger size (700 μm) by >50%. Depending on abrasives, BEF was found to be varied as large as by three-times, ranging from 4.37 to 14.41 mg/km/vehicle. As hardness of abrasive increases (SiC > Al2O3 > ZrSiO4), higher BEF was obtained, suggesting that abrasive wear directly contributes to emissions, evidenced by surface topology. Temperature-dependent data imply that particle emission for SiC abrasive is initiated at lower speed in WLTC cycle, where disc temperature (Tdisc) is ~100 °C, than that for ZrSiO4 (Tdisc >120 °C). Analysis of wear debris suggests that larger micron-sized particles include fragmented Fe lumps from disc, whereas smaller particles are, in part, formed by combination of oxidation and aggregation of nano-sized particles into small lumps.

We study the microstructure of deposited coatings formed by a composite material based on PG-10N-01 self-fluxing alloy and modified with a mechanically activated composite material obtained as a result of the self-propagating high-temperature sintering process. By the X-ray phase diffraction analysis, in the structure of the coating, we detect the presence of titanium diboride (TiB2), nickel boride (Ni3B), titanium oxide (TiO), and iron oxide (Fe3O4) inclusions distributed over the nickel matrix. It is demonstrated that the modifying addition promotes not only the refinement of structure in the course of electric-arc deposition but also the elevation of the levels of hardness and microhardness of the deposited layer and a 1.5-fold increase in the abrasive wear resistance as compared with the wear resistance of PG-10N-01 alloy. [ABSTRACT FROM AUTHOR]

Abrasive flow finishing (AFF) is an advanced finishing process employed for finishing macro- to micro-features of workpieces. Finishing improves the functioning of the components by reducing their surface roughness. AFF process uses a polymer-based flexible medium containing abrasive particles as a finishing tool. Medium used during the AFF process plays a vital role in deciding the final surface roughness on the workpiece surface. It is the medium properties in combination with AFF input parameters that decide the end surface roughness. Micro-features on the components are mostly machined with the help of processes involving thermal energy (electrical discharge micro-machining, laser beam micro-machining). This leads to the formation of hard recast layer on the micro-machined workpiece surface. Component size and hardness of the recast layer possesses a great challenge to the finishing processes. In the current article, an economic viscoelastic medium is developed for the finishing of micro-features and its detailed rheological study is carried out. Later, experimental study of the AFF process during the finishing of micro-slots (440 ± 10 µm width) in surgical steel is performed. Developed medium successfully finishes the micro-slots with an initial surface roughness of 3.54 µm to a final surface roughness of 0.21 µm (94.07% reduction in surface roughness). [ABSTRACT FROM AUTHOR]

A test procedure has been developed that models the wear of a material at friction against timber with abrasive particles impregnated into it. The procedure considers the kind and grain structure of an abrasive, timber species, technique of impregnating timber with abrasive particles, and testing configuration, temperature, and modes. The building up of the lateral surfaces of roller thorns with electrodes UONI-13/NZH and powder wire PP-Np-30Х4G2М is a more expedient method to make them more durable. It is shown that the grade 30 steel wear is characterized by the plastic straining of micro-volumes in the surface layer in the presence of individual marks and scratches, whereas the buildup wear is attended only by elastoplastic straining. The influence of such factors, as contact pressure, sliding speed, test temperature, and quartzy particle grain structure on the wear resistance of the studied surfacings is revealed. It is noted that the wear resistance of buildups UONI-13/NJ and PP-NP-30X4G2M for various test conditions is approximately equal to and 2.5–3 times as high as that of grade 30 steel; however, the preferable option for practical use on feed rollers is UONI-13/NJ due to its enhanced anticorrosion properties. [ABSTRACT FROM AUTHOR]

Being an advancement of conventional honing method, Magneto-rheological Abrasive Honing (MRAH) process is one of the unconventional nano-finishing processes which has the capability of finishing the non-magnetic freeform surfaces with good material removal rate. The magneto-rheological effect imparted by the carbonyl iron particles (magnetic particles) along with abrasives introduced through carrier medium directs the finishing action in MRAH. In MRAH process, up and down motion with rotational motion were assigned to the finishing fluid and the workpiece, respectively. Being a new process, there is a need to quantify and analyze the outcomes of machining parameters in addition to finishing time on % change in roughness value (%∆Ra). In the current study, machining parameters like magnetizing current, rotational speed of the workpiece, and finishing time were optimized to maximize %∆Ra using response surface methodology. An investigational study using center composite rotatable design followed by 'Analysis of Variance' was applied to evaluate the impact of influencing parameters. The regression equation obtained after elimination of insignificant terms was further optimized using response analyzer in Minitab 17. The outcomes obtained from regression equation were establishing a fine confirmation with the outcomes obtained from the experiments. [ABSTRACT FROM AUTHOR]

This research article presents the comparative investigation of physical, mechanical, and abrasive wear behavior of chopped glass and basalt fiber‐reinforced epoxy composites. The composites were fabricated by hand lay‐up technique. The fiber (glass and basalt) was varied in the range of 10 to 40 wt.% in the composite at an interval of 10 wt.% to find out the physical (density and void content), mechanical (tensile strength, flexural strength, and impact strength), and steady state abrasive wear rate, respectively. The Taguchi's design of experiment method was used for designing of experimental runs having input controlling variables like sliding distance, normal load, fiber content, and abrasive size. This study clearly demonstrated that with increase the fiber content, the density and void content of both fiber (glass and basalt) reinforced composite were increased. The basalt fiber‐reinforced composites show lesser voids than glass fiber‐reinforced composites. The tensile strength, flexural strength, and impact strength of both composites increased with increase the fiber content whereas glass fiber‐reinforced composites show slightly lower tensile strength, flexural strength, and impact strength than basalt fiber‐reinforced composites. However, as far as basalt fiber‐reinforced composites show better wear resistance than glass fiber‐reinforced composites. [ABSTRACT FROM AUTHOR]

Abrasive Water jet cutting process fits in the category of unconventional dimensional processing technologies, based on the principle of erosion with complex fluid environments, kinetically activated. Currently, there are multiple researches for process optimization, especially taking into consideration the economic criteria, due to relatively higher costs present in the case of abrasive waterjet cutting. The paper presents a synthesis of a study started from research within the National R & D Institute for Welding and Material Testing - ISIM TIMIŞOARA, especially in the direction of increasing the efficiency of using the abrasive material associated with this cutting process. Several patented results regarding the recycling of used abrasive material in other fields are presented, as well as prospects for further research by studying other methods aimed at reducing costs without reducing the level of quality for abrasive water-jet cuts. [ABSTRACT FROM AUTHOR]

In the defense industry, UHMWPE is primarily used as ballistic material because of its light weight, superior mechanical properties, and particularly, its excellent strength-to-weight ratio compared to metal alloys. In this study, the influence of the AWJ process parameters on machining UHMWPE material is investigated. Several UHMWPE plates have been prepared for trimming, pocketing, and hole making experiments using AWJ to understand the process parameter effects on performance measures. The design of experiment method has been used for all experiments and results are analyzed by the analysis of variance and response surface methods. Furthermore, a novel evolutionary optimization method known as particle swarm optimization has been applied to determine trade-offs between the conflicting performance measures of surface roughness and dimensional error in AWJ. With the resulting Pareto optimal solution curve, three industrial scenarios have been developed using k-means clustering algorithm and verified. [ABSTRACT FROM AUTHOR]

This article discusses advanced developments and applications of chemical mechanical polishing (CMP) published recently in the selected papers indexed by Web of Science. The topics covered are advances in slurry and abrasives, pads and conditioning, CMP for semiconductor device manufacturing, CMP for other applications, modeling and simulations, and CMP with ultrasonic vibrations, lasers, photocatalysts, or UV lamps. Nonspherical abrasive particles have been developed for CMP, resulting in increased material removal rates (MRRs). Advanced conditioning methods have been proposed to uniformly generate pad surface shapes. Fixed abrasive CMP has advantages with higher MRRs. New models for designing the pad and conditioner have been proposed, and more uniform pad shapes can be obtained. Integrated advanced process control improves the wafer-to-wafer variation. Dental implants treated by CMP perform equally or better than the baseline-machined implants and the biphasic calcium phosphate-treated implants. The slurry distribution and the abrasive behavior can be simulated by means of multiphase modeling. Molecular dynamics simulations can explore the mechanism of CMP. CMP of wafers can be simulated using an atomic force microscope with its tapping mode. Theoretical models have been developed to calculate removal depths, study the chemical action in CMP, and explore the crystal orientation effects. CMP assisted by ultrasonic vibrations increases CMP MRRs and lowers the roughness of polished surfaces. CMP assisted by using UV lamp power, femtosecond lasers, or photocatalysts enhances CMP MRRs. [ABSTRACT FROM AUTHOR]

Magnetic Abrasive Finishing (MAF) process is an advanced finishing method involving a dry medium comprising iron and non-magnetic abrasive particles. When this mixture is brought in the magnetic field, it forms a very fine, multiple, and flexible abrasive brushes, which can be used for finishing the magnetic as well as non-magnetic materials such as aluminum. For performing finishing operation on aluminum shaft, novel finishing tool having the fixtures for holding the workpiece and other comprising part have been designed, developed and fabricated. These fixtures are attached to a Lathe machine and moved along the length of the rotating workpiece. The non-magnetic material, which is chosen as aluminum, and the finishing operation is performed on it. Minimum surface roughness 96 nm after the actual surface finish of 400 nm with the change in percentage Ra 76% is achieved using the novel finishing tool. [ABSTRACT FROM AUTHOR]

In order to investigate the feasibility of minimum quantity lubrication technique in precision machining titanium alloys using abrasive belt grinding method, theoretical calculations and a series of detailed experimental studies were conducted in this paper. Material removal rate, grinding force, grinding temperature, abrasive belt wear, and machined surface quality were determined as the corresponding evaluation indicators. The signals of force and temperature in the grinding process were continuously collected by dynamometer and infrared thermal imager, respectively. The surface topography of the abrasive belt and workpiece were detected by a scanning electron microscope, and the machined surface roughness was measured by a surface profiler. The experimental results showed that the minimum quantity lubrication technology had obvious advantages in reducing abrasive wear and improving machined surface quality with suitable lubricating and grinding parameters. The observation result indicated that the compact microstructure and preferable fatigue strength can be obtained by using this assisted technique. Moreover, the addition of carbon nanotubes in grinding fluids was proven to be an effective way to further improve the effect of minimum quantity lubrication on assisted abrasive belt grinding of titanium alloys. [ABSTRACT FROM AUTHOR]

This paper shows the impact of different process parameters and powder characteristics on the material removal rate and surface roughness obtained in surfactant added Powder Mixed Wire Electric Discharge Machining (PMWEDM). Inconel-718 is selected as the workpiece material, which has ample application in the industries handling environment of extreme stress, pressure and temperature. It has high work hardening properties along with high rupture strength, fatigue, and creep, making it extremely difficult to machine. So, additives having different thermo-physical properties are studied to improve the machining efficiency. The additives experimented includes aluminium, silicon carbide, graphite, and aluminium oxide. It is found that the electrostatic force present creates an agglomeration effect with dielectric additive powders, causing inhomogeneity in the mixture. So, a surfactant SPAN20 is used here to maintain the homogeneity of the mixture. The obtained MRR and SR are then modelled and optimised through Particle Swarm Optimization technique (PSO). It is observed that the addition of SPAN20 has improved the MRR by 13.56% and, SR by 45.05%. Also, it has been found that due to the combined abrasive action, abrasive powders increase MRR significantly than others. Furthermore, it is found that low grit size powders with lower density produces better machined surfaces. [ABSTRACT FROM AUTHOR]