Development of a Micro-shot Peening Process and Testing of Micro-shot Peened Engineering Materials

A precision, air blast, shot peening machine was designed and developed and used to carry out peening operations on engineering materials and components. The machine was designed to allow all the variables of the peening process to be controlled and adjusted. The micro-shot peening process was applied to a series of standard High Speed Steel twist drills, carbide inserts for milling cutters, turning tools and EPDM material. The drills were used under controlled CNC conditions to machine mild steel plates. The useful cutting life of the drills was monitored. The surface finish and the dimensional accuracy of the holes were also recorded. Identical tests were preformed using standard unpeened drills. The results from the cutting performance of the peened and unpeened drills were recorded and compared. Similar peening operations were applied to carbide inserts for milling and turning tools and the performance of the peened tips was compared with unpeened tips. The application of micro-shot peening to standard cutting tools was evaluated. From the research work conducted, micro-shot peening is proved to be a useful process in improving the life of cutting tools. Tests carried out on EPDM material showed that the surface texture was improved by micro shot preening but no improvement was achieved in its tensile or fatigue properties