A Study On Abrasive Waterjet Machining Technology For Circular Parts

An experimental study on abrasive waterjet cutting process and strategy for circular parts was conducted. By analyzing machining mechanisms of three kinds of brittle materials such as glass, 90% alumina and marble which are cut by abrasive waterjet, it is found that microstructure of these materials have direct effect on material remove mechanisms. The material removing mechanism of glass in abrasive waterjet cutting is brittle fracture induced by high speed erosion of abrasives and waterjet. The material removing mechanism of 90% alumina is intergranular fracture caused by network cracks induced by impact. The material removing mechanism of marble includes cleavage of hard phrases and interphase crack along the weak interfaces between different phases.Phenomenon of erosion delay in forming kerfs by abrasive waterjet will cause kerf incline in straight cutting or kerf taper in circular cutting process. In cutting circular parts, the travel speed on jet inside wall is lower than that on jet outside wall, so the kerf of circular part is not symmetrical. For glass, alumina and marble, the lower travel speed on jet inside wall will minimize the kerf taper on inside wall of kerf. This is advantageous to cutting of circular parts whose inside wall is regarded as the part surface. On the contrary, the higher travel speed on outside wall will cause great kerf taper on outside wall of kerf and jet upward deflection zone. These are not advantageous to cutting of circular parts whose outside wall is regarded as part surface. The effect of jet pressure, standoff, travel speed and cutting radius on the cut depth and kerf taper of smooth zone was investigated. It is indicated that the cut depth of smooth zone enhances and the kerf taper of smooth zone minishes when the jet pressure increases. The cut depth of smooth zone reduces, whereas the kerf taper of smooth zone first reduces and then increses when the standoff enhances. So there is an optimum standoff. The cut depth of smooth zone reduces and the kerf taper of smooth zone increases, and hence the kerf quality degrades when the travel speed increases. The cut depth of smooth zone increases and the kerf taper of smooth zone minishes when cutting radius reduces.By orthogonal test and range analysis, the cutting parameters of circular parts were...