2008 Volume 74 Issue 11 Pages 1204-1209
This paper represents the influence of drilling conditions upon centripetal action with radial run-out in the micro drilling of printed circuit boards (PCBs). These were examined experimentally with micro drills of 0.1mm in diameter at a rotational speed of 3 x 105/min. The drilling behavior around contact area on a work surface was observed by a high-speed video camera. The conclusions obtained are as follows: 1) The centripetal action varies with physical properties of work material. The centripetal action is deteriorative in harder work material. 2) The centripetal action depends on feed rate. It is more effective at a lower feed rate, but doesn't depend on the geometry of drill tips. 3) Drilled hole quality is dependent on bending stiffness of a micro drill. The hole quality deteriorates at a higher bending stiffness.