Wear characteristics of exfoliated MoS2/polyamide-6,6 composite

Effect of exfoliation of MoS2 on the wear characteristics of the MoS2/PA-6,6 composite is investigated. Exfoliation of MoS2 is identified using X-ray diffraction, Raman spectroscopy, and transmission electron microscopy. Wear loss of composites is done using Taber abrasion tester with CS-17 abrasive wheel and atomic force microscope is used to characterize the worn surface. It is observed that wear loss of MoS2/PA-6,6 composite is strongly affected by content and exfoliation of MoS2. Wear loss of composites is decreased by the addition of MoS2 irrespective of exfoliation and it is improved with increasing filler content. Exfoliated MoS2/PA-6,6 composites show improved wear characteristic, that is, reduced wear loss, compared to the pristine MoS2/PA-6,6 composite. Addition of MoS2 induces less plastic deformation of the worn surface of composites, and it is more distinct for exfoliated MoS2.

Generation mechanism modeling of surface topography in tangential ultrasonic vibration-assisted grinding with green silicon carbide abrasive wheel

Tangential ultrasonic vibration-assisted grinding (TUAG) has a wide prospect in machining difficult-to-machine materials. However, the surface generation mechanism in TUAG is not fully recovered. This study proposes an analytical model of the surface topography produced by TUAG. Based on the model, the surface topography and roughness are predicted and experimentally verified. In addition, the influence of the grinding parameters on the surface topography is analyzed. The predicted surface topography well coincides with experimental measurements, and the prediction error in surface roughness Ra by the proposed model is less than 5%. Compared with conventional grinding, TUAG produces a surface with more uniform scratches and surface roughness Ra was reduced by up to 27% with the proper parameters. However, the improvement of surface roughness in TUAG is weakened when grinding speed or depth of cut increases. Moreover, the influence of the ultrasonic vibration amplitude on the surface roughness is not monotonous. With the grinding parameters selected in this study, TUAG with an ultrasonic amplitude of 7.5 μm produces the minimum surface roughness.

A Review Paper on Modification in Worktable of Belt Grinder

In most of the industries grinding is the final stage of finishing process. Grinding is a machining process which uses an abrasive wheel or belt type cutting tool. This grinding machine is used in various industries for finishing of work pieces and give high surface quality. Grinding with wheel or belt type cutting tool is used for different precision applications such as deburring in foundries and constructions, polishing, engraving and cut-off grinding. Our project provides flexible worktable through which angular grinding with better surface finish can be obtain. Also less force is generated through this arrangement which in turn provides firm gripping.

INFLUENCE OF THE GEOMETRIC CHARACTERISTICS OF THE DISCONTINUOUS PROFILE WORKING SURFACES OF ABRASIVE WHEELS FOR PRECISION AND TEMPERATURE WHEN GRINDING

Grinding is the most common finishing method for hardened steel parts. Grinding is accompanied by a large heat release in the cutting area, under the influence of which structural changes appear in the thin surface of the processed parts, tensile stress and even microcracks, which significantly reduce the operational reliability of machines that include these parts. The use of abrasive wheels with an intermittent working surface makes it possible to reduce the temperature in the area of contact of abrasive grains with the material of the workpiece and, as a consequence, stabilize the quality of the surface layer of the workpieces. High-frequency vibrations in the elastic system of the machine, accompanying the work of an intermittent wheel, are a positive factor that reduces the energy consumption of the grinding process. However, under certain conditions of dynamic interaction of the tool with the workpiece, parametric resonance may occur, which worsens the geometric and physical-mechanical parameters of the quality of the surface layer of the processed part. The aim of the work is to realize the possibility of predicting the quality parameters of the surface layer of parts during intermittent grinding by studying the influence of the design features of the macrotopography of the working surface of abrasive wheels and processing modes on the nature of the dynamic interaction of the tool with the workpiece and the heat stress in the cutting area. It was found that the parametric vibrations of the elastic system of the machine tool can be shifted to a more stable area, due to an increase in the number of interruptions of the working surface of the abrasive wheel with a constant ratio of the length of the protrusions and depressions. The increase in the number of breaks on the wheel also contributes to a decrease in temperature in the cutting area. It was found that to maintain the stable operation of the elastic system of the machine, it is necessary to reduce the number of cavities on the grinding wheel with an increase in the cutting speed. However, both of these actions are accompanied by an increase in the heat stress of the grinding process. It has been experimentally established that for ordinary (pendulum) grinding, it is possible to achieve an increase in processing productivity by increasing the speed of the longitudinal movement of the table.