The damage to human dental enamel under cyclic, axial contacts in a silica particle medium is investigated. It is found that such damage is hierarchical, affecting different length-scales of the ...enamel structure. At the contact surface, it consists of micron-sized defects, with an attendant increase of surface roughness due to microindentation of the abrasive particles. Below the surface, demineralization of the enamel is observed, which is attributable to inelastic processes at the nanoscale. Axial-only contacts in particulate media result in negligible wear at the macroscopic scale, but may degrade the fracture strength. Potential implications of these results in the fields of dentistry and biology are discussed.
With the development of mould manufacturing industry, the high precision polishing technologies of Ni–P-coated SKD11 steel are in high demand. In this work, the factors influencing the magnetic ...material polishing process were determined by investigating the force distribution of carbonyl iron (CIPs) and abrasive particles (APs) in the working surface of magnetorheological fluid (MRF). The influence of certain factors, such as the diameters of the CIPs and the APs and the current and working distance (K), on the polishing surface quality, was assessed by fuzzy grey and Taguchi analysis. Results showed that the values of the fuzzy grey relationships with the surface quality of the factors were 0.4914, 0.7797, 0.6686 and 0.7461. Result showed that the fuzzy grey relationship point of factors known as diameters of the AGs had the most remarkable influence on the polishing effect, and the effect of CIP diameter was insignificant. The MRF contained commercially available CIPs that had been successfully applied for polishing the surface of magnetic materials with extremely high accuracy (surface roughness Ra = 0.561 nm) without leaving scratches on the surface after polishing.
Industry demands Nano level of surface finishing and development of advanced material makes finishing difficult to attain for modern grinding industry. The Electro-Chemical Magnetic Abrasive ...Finishing (ECMAF) is an advanced abrasion based finishing process used to finish very hard material with superior surface finishing. In ECMAF, soft film generated by electro-chemical dissolution (ECD) on the workpiece is removed by gentle finishing force of micron size abrasive particles of Magnetic abrasive Finishing (MAF). In this process, the material is removed in the form of microchips without sub surface damage. This paper presents the experimental investigation of SS 304 workpiece using indigenously newly developed ECMAF set up that eliminates the problem of washing of abrasive particles by electrolyte from the working gap. The Un-bonded Magnetic Abrasive Particles (UMAPs) are prepared by mechanical mixture of ferromagnetic particles and abrasive particles. The experiment is designed using L25 orthogonal array of Taguchi Methodology and effect of working gap, workpiece rotational speed, electrolytic flow rate and electrolytic current on the Surface Roughness (SR) and Material Removal (MR) is studied. The result is analyzed using ANOVA and found the working gap to be the most significant process parameter followed by workpiece rotational speed and electrolytic current for SR while the working gap is found to be most the significant process parameter for MR.
In this paper, the magnetic abrasive finishing (MAF) on AZ31B magnesium alloy and 7075-T6 aluminum alloy was carried out, using the spherical composite magnetic abrasive particles (MAPs) prepared by ...our research group independently. The finishing experiments were conducted by using the Al
2
O
3
/Fe-based MAPs and SiC/Fe-based MAPs, respectively. The results of our works show that there are disparities in the mutual suitability between the MAPs with different abrasive phase and the processed materials. After finishing, the surfaces of workpieces with the foggy mirror effect are obtained. The effects of MAF with different abrasive phase on the surface quality were investigated. The material removal mechanism and surface formation processing of workpieces in MAF were analyzed. The conclusion is as follows: in MAF processing, under the combined action of plastic deformation flow, skiving, extrusion, and chemical reaction, the surfaces of workpieces meet the requirements of surface quality.
The paper deals with the verification of suitability of water jet and abrasive water jet application for the disintegration of rotating samples of wood plastic composites (WPCs) with diameter
d
= ...36 mm. The influence of selected technological factors (traverse speed of cutting head
v
mm/min and size of abrasive particles MESH) on the topography of resulting surfaces has in particular been studied. Surface topography and quality have been assessed using the methods of optical and confocal microscopy and optical profilometry. The presented procedures and results of experiments demonstrate the technology of abrasive water jet as an appropriate tool for the rough machining of WPCs and similar composite materials. In addition, the application of this technology can effectively solve the problem of the melting of the polymer matrix and its subsequent sticking to the functional parts of a cutting tool resulting from conventional turning.
Micro-abrasion remains a test configuration hugely used, mainly for thin coatings. Several studies have been carried out investigating the parameters around this configuration. Recently, a new study ...was launched studying the behavior of different ball materials in abrasive particles' dynamics in the contact area. This study intends to extend that study, investigating new ball materials never used so far in this test configuration. Thus, commercial balls of American Iron and Steel Institute (AISI) 52100 steel, Stainless Steel (SS) (AISI) 304 steel and Polytetrafluoroethylene (PTFE) were used under different test conditions and abrasive particles, using always the same coating for reference. Craters generated on the coated samples' surface and tracks on the balls' surface were carefully observed by Scanning Electron Microscopy (SEM) and 3D microscopy in order to understand the abrasive particles' dynamics. As a softer material, more abrasive particles were entrapped on the PTFE ball's surface, generating grooving wear on the samples. SS AISI 304 balls, being softer than the abrasive particles (diamond), also allowed particle entrapment, originating from grooving wear. AISI 52100 steel balls presented particle dynamics that are already known. Thus, this study extends the knowledge already existing, allowing to better select the ball material to be used in ball-cratering tests.
Similar to grinding, a large number of diamond abrasive particles are used on the wire saw surface to remove materials by interaction with the workpiece. Therefore, the surface morphological ...characteristics of the wire saw, such as particle size and cutting edge height, have important effects on cutting performance of the wire saw. In terms of the complex diversity of the geometric characteristics and the randomness of the spatial position of the abrasive particles on the wire saw, the irregular polyhedron generated by the random space plane sphere method is used to simplify the abrasive particles and the space coordinates of the abrasive centre are created by random algorithm. As a result, a more realistic 3D model of the wire saw surface is constructed. A finite element method was employed to establish a cutting force simulation model of the wire saw with multiple abrasive particles for hard and brittle materials cutting processing, and the influence of feed rate and wire saw speed on cutting force was analysed; Based on the contact arc length, the cutting force model of multiple abrasive particles is extended to the macro level of wire saw cutting, and the reliability of the proposed model is verified by 4H-SiC cutting experiments. The established finite element model for microscopic simulation of the cutting process lays a foundation for cutting force prediction, tool parameter optimization and further research on wire saw cutting mechanism.
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