Monitoring the abrasive waterjet drilling of Inconel 718 and steel: a comparative study

This paper presents an experimental study on abrasive waterjet (AWJ) drilling of Inconel 718 and AISI 1040 steel, with an aim to understand the AWJ hole drilling performance and to investigate the process monitoring strategy by using acoustic emission (AE). In the experiments, pressure levels were set from 200 to 350 MPa at intervals of 50 MPa, and drilling time between 5 and 30 s at intervals of 5 s. It is found that the hole depth increases along with the drilling time at a slowing down penetration rate. A higher pressure results in a higher penetration rate. While there exists a direct influence of the material property on the drilling efficiency, it has limited significance with regard to the diameter of the hole produced. AE-RMS signal is demonstrated to be able to reflect the decreasing trend of the penetration rate and the influence of the pressure. A strong correlation between the penetration rate and AE-RMS values in AWJ hole drilling is shown through correlation analysis. The AE-RMS is also substantially affected by the material properties. A discrepancy of the AE-RMS under similar condition may suggest an anomaly in this cutting run.