| Electro-discharge machining (EDM) is universally used in the die and mold making industry because of its ability to machine hardened steel into intricate shapes. However, the EDM process also creates a hard, brittle recast layer on the die surface, which must be removed by manual methods before the die can be put into service.; Recently pulsed electrochemical machining (PECM) has been proposed as a means of automating the removal of the EDM recast layer. Electrolytic methods such as PECM are known to create stress-free surfaces, but the control of these processes has proved to be difficult in the past. Because the power supply in PECM is pulsed, it offers more control to the user than has conventional ECM.; This dissertation presents a model for optimizing the die making process, with particular emphasis on optimizing the PECM pulse parameters to provide an optimum die surface in minimal time. The model is applied to a COTAC-51 PECM machine, and the results show significant improvement in the surface finish of the H-13 steel surface, and in the mechanical fatigue life of specimens machined from hardened premium grade H-13 tool steel. |
