The grinding wheel cover is an important safety part that protects the machine tool operator from abrasive fragments. However, the collision phenomena of the brittle and porous abrasive products have not been clarified. In addition to experiments, numerical analysis is generally used to clarify the collision phenomena. On the other hand, it is difficult to reproduce the fracture of abrasive products using existing general collision analysis methods. This study was performed to investigate the feasibility of abrasive product fracture analysis using Solid to SPH, which replaces the solid element of the finite element method that has reached the failure criteria with the particle of smoothed particle hydrodynamics. Comparison of the analysis results with the actual compression test results indicated that abrasive product fracture analysis by Solid to SPH can reproduce the actual phenomena well in terms of load-displacement relationship and fracture shape.
Hot steel can be cut more easily than the cold steel. Experimental results of cutting hot steel with an abrasive water jet (AWJ) at temperatures > 1000°C have not been reported. Here, basic laboratory experiments with the AWJ showed the cutting phenomena using a small work piece of hot steel compared with cold steel. The experimental results showed that the relationship between cutting speed and thickness of hot steel was unexpectedly almost the same as for cold steel. According to the thermocouple measurement, the center temperature of the steel was maintained above 800°C. However, as estimated by heat transfer analysis, the surface temperature of the hot steel decreased to < 300°C. Therefore, when the hot steel was cut with the AWJ, the cut surface on which the abrasive acts became cold steel.
We developed a precision laser slicing technology for single-crystal SiC. To reduce kerf-loss, the mechanism underlying laser mark formation inside the wafer was determined. The laser marks consist of amorphous modified parts and cleavages formed a periodic serrated shape along the off-angle. This phenomenon is caused by interference of laser reflection on the cleavage, resulting in increased laser absorption. Therefore, excess off-angle cleavage growth occurred resulted in increased kerf-loss. Slicing experiments with SiC wafers were carried out taking this mechanism into consideration, and precision laser slicing with kerf-loss < 36 μm was achieved.