Improvement of Rock Cutting Performance through Two-Pass Abrasive Waterjet Cutting

Abrasive waterjet (AWJ) has been widely used for the cutting of hard materials such as rocks. The AWJ cutting of rocks has been well documented in the relevant literature. In these studies, one-pass cutting is employed as the cutting mode. There is no study focusing on the two-pass AWJ cutting of rocks. Therefore, this study aims to fill this gap. Therefore, in the current study, the physicomechanical properties of the rock subjected to cutting are first determined. Following, the workpieces are cut with both one-pass and two-pass cutting modes. In the tests, cutting time is kept constant to compare the performances of cutting modes in terms of the smooth cutting depth and surface roughness. Kerf profiles of the cutting modes are also compared. In the study, significant relationships were not determined between the cutting parameters (abrasive flow rate and standoff distance) and performance outputs for the cutting modes. This may be attributed to the cutting parameters studied in a narrow range. The results indicate that two-pass cutting with higher speeds provides higher smooth depths than one-pass cutting at lower speeds. Two-pass cutting increases smooth depth up to 47%. Results show that surface quality could be improved by two-pass cutting, expanding the smooth zone and reducing the sizes of the striations. The results also show that two-pass cutting improves surface roughness by up to 25%. It is revealed that kerf wall inclination is reduced by two-pass cutting in the upper and lower parts of the kerf. A widened portion caused by the first pass is observed in the final kerf. It can be noted that two-pass cutting cannot provide any improvement in the top kerf width.