Erosion Rate, Surface Finish and Electrode Wear in Electric Discharge Machining (EDM) of Dental Alloys.

A precise fit of dental restorations is critical in all aspects of prosthetic dentistry. Fabrication of a prosthesis with a high degree of accuracy is difficult due to the dimensional changes of different dental materials. EDM is an extremely accurate non-contact machining process with a precision as small as 0.002 mm. The objectives of this study were to investigate how changes in amperage and on-time of the EDM process affect the metal removal rate MRR and surface finish Ra of representative dental materials. The percentage of electrode wear PEW of representative electrode materials in different metal-electrode combinations was also studied. Three representative dental metals workpieces were used Type III gold Ney, Olympia ceramo-metal Alloy Jelenko and titanium Ti Rematitan. Type III gold and ceramometal alloy were cast in bars 6mm square and 30 mm in length. Ti ingots were used as provided by manufacturer.