Economic drilling conditions for a given deburring radius

Abstract

Burr has usually adverse effects on the assembly and performance of mechanical, pneumatic and hydraulic systems. It is therefore necessary to know how to minimize the burr size in both the design and in process planning phases of machine parts. Electrochemical deburring (ECD) is now providing a simple and economical approach to selectively removing burrs from inaccessible areas with consistent results and absolute uniformity. It has many great advantages as mentioned by several investigators [Adachi et al., A study on burr in low frequency vibratory drilling, in: Proceedings of the Fifth International Conference on Production Engineering, Tokyo, 1984, pp. 246–251; Nakayama, Ann. CIRP 36 (1) (1987) 33; Welte, Electrochemical deburring (ECD) of intersecting holes in aircraft engine components — reliable and cost saving technology, SME Technical Paper Series No. 79-736, 1979]. ECD systems have been developed to handle pieces in every way from manually one part at a time, to completely automated transfer lines processing several pieces at a time. In order to achieve maximum productivity and minimum cost of drilling and ECD of a hole, it is necessary to drill under such conditions which give least possible burr height. The aim of the present investigation is therefore to find out the best combination of drilling and enlarging as well as chamfering prior to enlarging, which minimizes the obtained burr size. A flowchart is developed for the determination of the optimum conditions of drilling with minimum manufacturing cost from the point of view of burr formation. It enables also the evaluation of the ECD time to obtain the required deburring radius with minimum cost for drilling followed by ECD, especially in case of drilling intersecting holes.