印刷电路板微小钻头的刚性解析

在印刷电路板的微孔加工中,因钻头的直径很小,刚性较差,钻孔的出口与入口位置偏差过大,而影响微孔加工的精度。本文利用钻头不同位置不同方向的惯性矩和挠曲对其弯曲刚性进行解析。指出,在钻头螺旋槽的终点,惯性矩随螺旋槽的变化而急剧地变化,从而确定了钻头易折断的位置,得出螺旋槽终结处圆滑过渡可减小钻头挠曲的结论,并且在不考虑排屑及其他条件的情况下,由于增大螺旋角可以减小钻头挠曲的异向性,因此对提高钻头的刚性,保证微孔加工的位置精度也是有利的。

Analysis for the Rigid of Micro-drill for Printed Circuit Board

In processing the tiny hole on printed circuit board precision is effected by the tiny diameter of the solid drill, its poor rigdity and excessive difference between locations of the inlet and the outlet of the drill.This paper by means of different locations inertia moment of different directions and bending of the drill,analyses its bending rigidity.It points out that at the end of the spiral groove,moment of inertia changes dramatically as spiral groove changes, thus, determining the palce where the drill is likely to break,and concluding that smooth transition at the end of spiral groove can reduce the bending of the drill.Moreover, not considering removing scraps and other situation, increasing spiral angle can reduce the difference of drill bending, therefore,helpful for increasing the drill rigidity and precision of drill location.