Submerged Abrasive Water Jet Piercing/Drilling: Preliminary Tests

In the technological process of cutting by means of an abrasive water jet, the so-called piercing is often used when starting the operation of cutting. As the piercing is a time-important part of the process, it is advantageous to reduce the time by using different piercing strategies. This article discusses a nozzle circling method that reduces the time required for piercing. The tested circling diameters varied from 0 to 1.55 mm. It was found that the time required for piercing decreased to one sixth with the biggest circling diameter. Another issue discussed in this article is the piercing in submerged water. This method is mainly used to ensure comfort and safety of operators using the water jet. The advantage is the reduction of dust, noise and jet reflection. However, the jet efficiency decreases. An experiment was carried out at five standoff distance settings. The experiment has shown that the resulting times differed only minimally from the piercing in air. Using a digital microscope and subsequent image analysis, the jet behavior as it passed through the material was examined and recommendations for using the nozzle circling method were designed.