Analysis of the initial damage region in agate plates cut by abrasive waterjet (AWJ) process

The abrasive waterjet (AWJ) cutting process has been widely used in the gemstone processing industry due to its versatility and accuracy characteristics. The influence of the parameters involved in the AWJ process has been investigated by many authors, and it can be seen that in each application different responses are reported. In agate processing via AWJ, the final quality of the piece depends on the properties of the initial damage region (IDR), such as width and depth. The present study has purpose to investigate the influence of the standoff distance, traverse speed, working pressure, and abrasive mass flow rate on the depth and width of the IDR when cutting agates through AWJ. A set of 80 samples were analyzed, and the measurement of the depth and width of the IDR was performed through three-dimensional scanning using X-ray computed microtomography (XCM). This technique allows assessing the IDR in an accurate and reliable way. The results showed that, within the investigated range of parameters, the width and depth of the IDR vary between 0.3 and 0.7 mm. Also, the IDR in the agate plates is strongly influenced by the standoff distance.