The model of product distortion in AWJ cutting

Abstract

The abrasive water jet (AWJ) retardation inside the cut material, the characteristic phenomenon of the AWJ cutting, causes declination of the kerf sidewalls especially in corners and curvatures. This paper is aimed at a description of the origin of these negative consequences of jet retardation. The model for calculation of the limit traverse speed from both the jet parameters and material properties has been derived using laws of conservation. The equation expressing dependence of the angle between the tangent to the striation curve and the impinging jet axis on the depth of jet penetration into material has been used for evaluation of the product distortion in the cutting process. Proposed model has been applied for setting up the tilting angle of the cutting head during the AWJ cutting process to reduce the product shape distortion. The model was supplemented by geometrical analysis of curved parts of cut trajectories. The resulting equation makes possible to calculate the shift of the jet trajectory at the outlet side of the workpiece from its regular position determined by projection of the trajectory at the inlet side of the workpiece along the jet axis. The model is capable to determine the appropriate tilting angles of the cutting head for compensation of the jet retardation and the taper. The experimental data measured on metal samples seem to be in a good accordance with the proposed model.