Cutting performance and tool wear in laser-assisted grinding of SiC_f/SiC ceramic matrix composites

Abstract

Ceramic matrix composites have high hardness, so their machining requires high grinding forces that cause severe wear of the grinding head. To investigate this problem, the present study investigated the cutting performance of conventional grinding (CG) and laser-assisted grinding (LAG) of SiCf/SiC ceramic matrix composites using electroplated diamond grinding heads. Firstly, a three-dimensional transient heat transfer model based on a Gaussian heat source was developed to observe the surface and internal temperature field distributions of SiCf/SiC ceramic matrix composites subjected to laser irradiation. Secondly, the effects of laser heating temperature on the workpiece surface on the grinding forces were analysed. It was found that the axial and feed grinding forces were more than 40% lower under LAG than CG due to the removal mechanism of the SiC matrix changing from brittle fracture to ductile fracture and the oxidation reactions occurred in the SiCf/SiC ceramic matrix composites. Thirdly, the material removal mechanism was analysed by observing the morphology of machined surfaces, which showed that ductile removal from the SiC matrix occurs during LAG. Finally, it is also founded that the mean height of exposed abrasive grains from machined surface was reduced by 1.02 μm, 12.52 μm in LAG and CG respectively. The forms of wear caused by abrasive grains were studied. Under CG, the abrasive grains mainly exhibit cleavage fractures; while under LAG, micro-abrasion is the main wear form.

Review on Abrasive Machining Technology of SiC Ceramic Composites

“…Kong et al [ 28 ] investigated the cutting performance of CG and LAG of SiC f /SiC using electroplated diamond grinding heads. A three-dimensional transient heat transfer model based on a Gaussian heat source was developed to investigate the distribution of temperature fields on both the surface and subsurface of SiC f /SiC subjected to laser irradiation.…”

“… The cutting performance of CG and LAG of SiC f /SiC by Kong et al [ 28 ]: ( a ) LAG system; ( b ) schematic diagram of LAG; ( c ) comparison of CG and LAG forces; ( d ) laser temperature field; ( e ) surface morphology; ( f ) grinding head abrasive grains wear forms; ( g ) mean heights of exposed abrasive grains. …”

“…In addition, laser irradiation causes complex reactions, such as sublimation, decomposition, and oxidation, on the surface of the material and generates SiO2 and Si as well as recrystallized SiC, resulting in the formation of a porous SiC layer (thermal metamorphic layer) on the subsurface, as shown in Figure 6b. In the LAG, the normal grinding force, the tangential grinding force, the specific grinding energy, and surface roughness Kong et al [28] investigated the cutting performance of CG and LAG of SiC f /SiC using electroplated diamond grinding heads. A three-dimensional transient heat transfer model based on a Gaussian heat source was developed to investigate the distribution of temperature fields on both the surface and subsurface of SiC f /SiC subjected to laser irradiation.…”

Research on grinding wheel wear measurement methods: Current status and future perspectives

“…Qian [65] 用显微镜观察法研究了 CBN 晶粒的磨损行为, Kong [66] , Li [67] 和 Rao 等 [68] 用显微观察法研究了金刚 石砂轮的磨损特征. Dai 等 [69] 采用原子力显微镜测量 了单颗金刚石磨粒的微观形貌, 研究了单颗磨粒的…”