Manufacture of diamond-coated cutting tools for micromachining applications

Abstract

Micro- and nanomachining cutting tools are currently being developed in order to extend the range of manufacturing technologies available to the micro and nano engineer. Conventional diamond tools used for grinding operations have a number of problems associated with heterogeneity of the crystallites, decreased cutting efficiency and short life. Micromachining cutting tools are manufactured by imbedding diamond particles into the tip of the microtool using a suitable binder matrix material. The use of a diamond coating may offer an improvement in microtool technology. Chemical vapour deposition (CVD) of diamond coatings onto a cemented tungsten carbide (WC-Co) substrate is difficult. Generally, the adhesion of the diamond coating to cemented carbide substrates is poor. It is reported that binder materials such as cobalt can suppress diamond growth and enhance graphitic deposits, which cause poor adhesion and low diamond nucleation density. The effects of process parameters such as filament position, filament and substrate temperature and pretreated substrate material on the coating properties have been investigated using a number of experimental techniques.