Proposal of coarse grain PCD with fine particles of boron-doped diamond mixed in

摘要

For machining MDF (medium density fibreboard) materials in the woodworking industry, tools tipped with a coarse grade PCD (polycrystalline composite diamond) composed of coarse grain (over 25 μm in diameter) diamond particles are preferably used in general. In the existing coarse grade PCD, fine (a few micron meters or so) diamond particles are mixed in for the purpose of filling the voids between the coarse diamond particles. However, the fine diamond particles immixed in the PCD tend to be deteriorated or burned down easily during synthesis, causing some problems such as strength reduction and roughness worsening. The authors proposed a new PCD immixed with fine particles of boron doped diamond with superior heat resistance. As a result of the heating test, the new PCD showed higher heat resistance in terms of weight reduction and surface condition. Specifically, while a lot of dents formed by burning down of the fine diamond particles were seen on the surface of the existing PCD after the test at 900°C, only a few dents were observed on the new PCD. In the wire EDM cutting test, machining speed was improved in the new PCD.