Face Grinding Surface Quality of High Volume Fraction SiC_(p)/Al Composite Materials

The existing research on SiC_(p)/Al composite machining mainly focuses on the machining parameters or surface morphology.However,the surface quality of SiC_(p)/Al composites with a high volume fraction has not been extensively studied.In this study,32 SiC_(p)/Al specimens with a high volume fraction were prepared and their machining parameters measured.The surface quality of the specimens was then tested and the effect of the grinding parameters on the surface quality was analyzed.The grinding quality of the composite specimens was comprehensively analyzed taking the grinding force,friction coefficient,and roughness parameters as the evaluation standards.The best grinding parameters were obtained by analyzing the surface morphology.The results show that,a higher spindle speed should be chosen to obtain a better surface quality.The final surface quality is related to the friction coefficient,surface roughness,and fragmentation degree as well as the quantity and distribution of the defects.Lower feeding amount,lower grinding depth and appropriately higher spindle speed should be chosen to obtain better surface quality.Lower feeding amount,higher grinding depth and spindle speed should be chosen to balance grind efficiently and surface quality.This study proposes a systematic evaluation method,which can be used to guide the machining of SiC_(p)/Al composites with a high volume fraction.

Thermal Aspects for Face Grinding of Ceramics

To meet the increasing demand on the quality and co st of precision structural components, extensive studies on high efficiency and pr ecision machining of ceramic materials, including face grinding, have been condu cted over the past several years. However, there are few reports about the mecha nism in face grinding of ceramics, especially the thermal aspects during the gri nding process. In the present study, experiments of face grinding two typical ce ramics were carried out to study themal aspects at the wheel-workpiece contact zone. The present investigation was undertaken to experimentally study the energy part ition to workpiece and thermal characteristics during face grinding of two typic al ceramics. For this purpose, grinding temperature distribution in the ceramics workpiece was calculated with the classic moving heat source theory. The grindi ng temperature at the wheel-workpiece contact zone was measured under different machining conditions using a grindable foil thermocouple. Combining the analyti cal results and the experimental result for temperatures, the mechanism of energ y partition in face grinding of ceramic materials was discussed. According to the experimental results and the comparison of theoretic and measur ed temperature profiles, temperature characteristics and mechanism of energy par tition in face grinding of ceramic materials were discussed. Temperature rise in the workpiece and energy partition during the grinding process were found to be derictly related to the machining parameters and the mechanism of mateirial rem oval. The increasing of either v w or a p can lead to an increase of temperatu re. The temperature rise in Si 3N 4 is much lower than that in ZrO 2 under th e same condition, which might be attributed to the different material removal me chanisms. Both temperatures in dry grinding and in wet grinding are not high eno ugh to cause thermal damage to ceramic materials. The value of energy partition increases with the increasing of v w. The energy partition for Si 3N 4 grindi ng is much lower than that for ZrO 2 grinding, which is consistent with the res ults of grinding temperatures.