Modification of SS 304 using semi automatic sandblasting for improvement of roughness and grade quality

Abstract

Abstract This study aimed to discover the effect of pressure and spraying angle to surface roughness and flatness of stainless steel SUS304 after the sandblasting process. In this study, the variation of the compressor pressure were 4, 5, and 6 bar, while spraying angles were 45°, 60° dan 90°. Silica sand was used as the abrasive particles, which is sprayed onto the specimen surface. The size of silica sand was 200-300 µm. While, the sprayer feedrate was 5 cm min−1 and the distance between nozzle and specimen surface was 15 cm. There were two of spraying methods, i.e., one side spraying and two sides spraying with the same pressure and spraying angle in both sides. Both spraying methods were conducted by using the support of DIY CNC equipment. The roughness test only conducted on the specimen with one side spraying. It gives the result of a higher spraying pressure increased the roughness value due to a bigger sand collision force and more sand mass that collide the surface. The sandblasting process was resulted the presence of compressive residual stress and surface elongation that caused the material become warp and producing a deflection angle. The deflection angle indicates the surface flatness quality of a material, where a smaller deflection angle means better quality of surface flatness and vice versa. Too big of a deflection angle requires a further process. This study analyzed the comparison of one side spraying and two sides spraying with the same spraying variables on both sides. It is discovered that two sides spraying produced a better surface flatness.