Dry and semi-dry machining using finely crystallized diamond coating cutting tools

Finely crystallized diamond coatings with smooth surfaces have recently been developed by the authors. In the present study, shaft tools with these new coatings were applied to dry and semi-dry machining of highly adherent aluminum alloys whose efficient means of dry machining have not yet been established for. In comparison to the case of conventional diamond coatings with rough surfaces, more than four times longer durability of drills was realized in perfectly dry condition. In the case of minimum quantity of lubricant condition, the lifetime was found again to be more than four times longer and successfully achieved the largest improvement of diamond-coated drills ever reported in semi-dry condition.