PREVENTION AGAINST BREAKAGE OF MINIATURE DRILLS

Abstract

Mechanical drilling is a fundamental machining technique of cylindrical holes with diameters of less than 1 mm. During the drilling on the miniature drills there act relatively large cutting forces, which, in presence of many disturbances, often cause tool breakage. The paper describes investigations into the thrust and the torque changes and fluctuations, depending on drilling parameters and process conditions. The various possibilities of reduction of the tool loading are discussed, like using the lubricants and interrupt drilling cycle. However, in some cases the effective breakage prevention requires special control systems installed in the drilling machine.