Evaluation of Geometric Defects Produced in Abrasive Water Jet Drilling of Steel S275JR

Drilling of metal alloys is an operation that is still performed today in many industrial sectors such as aeronautics, automotive or civil engineering. This is mainly due to the high number of mechanical joints that must be made in structural elements. However, it is known that conventional drilling operations can generate defects on the machined surface mainly due to the effect of temperature on the tool and the material. For this reason, a non conventional process such as abrasive water jet machining (AWJM) is ideal for this type of operation. The decrease in temperature along the process minimizes the defects generated while keeping a high surface finish on the machined part. Therefore, this research has been carried out, where a 2 mm thick S275JR steel has been drilled by abrasive water jet. An experimental methodology has been developed to carry out the drilling. The input parameters include hydraulic pressure (P), stand of distance (SOD), abrasive flow rate (AMF) and traverse speed of the tool head (TS). In order to carry out the experiment satisfactorily, micro-drilling trials have been carried out leaving the TS parameter fixed in order to know the behavior of the material against the kinetic energy presented by the water jet equipment. These holes have been analyzed by means of the geometrical defects obtained in the form of diameter and kerf taper angle. Finally, the most relevant conclusions of the research have been developed, where it is emphasized that kerf taper (KT) angle increases drastically with the increase in SOD, giving greater results in area and with a greater amount of deformations and projections.