Journal of Applied Mechanical Engineering

Recycling of WC (Co) drilling and milling tools by controlled plasma oxidation of used CVD-diamond coatings without damage to tooth edge

International Conference on Design and Production Engineering

July 25-26, 2016 Berlin,Germany

Tatsuhiko Aizawa, Kazuhisa Yamauchi and Ercy Edo Yunata

Shibaura Institute of Technology, Japan

Posters & Accepted Abstracts: J Appl Mech Eng

Abstract:

The CVD-diamond coated WC (Co) tools have been widely utilized for dry drilling, milling and machining of CFRP (Carbon Fiber Reinforced Plastics) and CFRTP (Carbon Fiber Reinforced Thermo-Plastics) in airplane and automotive industries. The severe mechanical interaction between hard diamond coatings and carbon fibers often results in damage and deterioration of diamond films; e.g. a single diamond coated tool is damaged only after continuous drilling of 10 to 20 holes. The tooth-structure, fine machined WC (Co) tool substrate costs so much that it must be recycled after complete removal of used diamond films without damage to the WC (Co) substrate. In the present paper, the high density plasma oxidation method is proposed to make complete ashing of the used CVD-diamond coatings from the WC (Co) tooth surfaces and to adjust the bare WC (Co) tooth surfaces for nucleation of CVD-diamonds in recoating. The ashing rate by the present method reaches to more than 10 m/hr and the shrinkage of tooth edge is limited to be less than 1 μm. No diamond residuals are detected by the Raman spectroscopy; SEM observation reveals that the nucleation sites by decobalting for growth of diamond films are recovered by this processing. The plasma oxidation behavior is discussed through the quantitative plasma diagnosis; the emissive-light optical spectroscopy provides a population of oxygen activates species and the Langmuir probe measurement works to describe the spatial distribution of electron and ion densities. The effect of tooth structure and tooth shape on the oxygen ashing process is also discussed to describe the oxygen plasma state around the tooth surfaces.

Biography :

Email: taizawa@sic.shibaura-it.ac.jp