Material Removal in WEDM of PCD Blanks

Polycrystalline diamond (PCD) tools are now widely used in machining a large variety of advanced materials. However, the manufacture of PCD tool blanks is not an economical and efficient process. The shaping of PCD blanks with conventional machining methods (such as grinding), is a long, labor-intensive and costly process. Wire electric discharge machining (WEDM) promises to be an effective and economical technique for the production of tools from PCD blanks. However, a knowledge base for wire electrical discharge machining of PCD blanks needs comprehensive investigations into the proper parameter setting, metal removal mechanisms, and surface integrity of machined blanks. This paper presents the results of experimental and theoretical investigations of the influence of discharge frequency and discharge energy on the material removal rate of WEDM of PCD blanks. The mechanism of removing diamond grains from the matrix during electrical erosion is also discussed on the basis of thermal stresses between the diamond grain and cobalt phase.