Drill bits for drilling holes in pcb boards

Abstract

A drill bit for drilling a PCB comprises a body (10). One end of the body (10) is a drill tip, and a groove and breadth ratio constant segment and a groove and breadth ratio alternating change segment are sequentially disposed from the end where the drill tip is located to the other end of the body (10). A long spiral groove (101) and a short spiral groove (102) that are spirally surrounding and that are not intersected are formed in the outer side of the body. The groove and breadth ratio of each of the long spiral groove (101) and the short spiral groove (102) is constant at the groove and breadth ratio constant segment. The groove and breadth ratio of each of the long spiral groove (101) and the short spiral groove (102) changes alternately at the groove and breadth ratio alternating change segment. The short spiral groove of the groove and breadth ratio constant segment is connected to a staggered groove staggered with the short spiral groove. In the drill bit for drilling a PCB, the double-spiral-groove non-intersection design is used, the groove and breadth ratio alternately changes on the rear section of the drill bit, the two grooves discharge cuttings independently, the drill bit is unlikely to be blocked by the cuttings, and the cutting temperature can be controlled in a small range. In addition, the area of a cross section entity of the spiral groove and the core thickness taper can be increased, the bend resistance strength of the drill bit is improved, the hole site machining precision is high, and the machining quality of a drilled hole is good.

Description

technical field [0001] The invention belongs to the technical field of drill bits, in particular to a drill bit used for drilling holes in PCB boards. Background technique [0002] At present, the size of the motherboard of electronic equipment is becoming smaller and smaller, and the chips are highly integrated and arranged more and more densely, which puts forward higher requirements for the position accuracy of the printed circuit board (PCB board) holes connecting the chip pins. Different designers have multiple angles and methods to improve the drilling accuracy of PCB micro-drills, but designers generally believe that for micro-drills, the hole position accuracy of drilling mainly depends on the stiffness of the drill bit, specifically, there are cross-sectional shape, drill Factors affecting stiffness such as core thickness, helical groove angle, and edge groove length. [0003] The Japanese scholar Hoshi Xingyi adopted the method of changing the helix angle and chan...

AI Technical Summary

Problems solved by technology

However, the asymmetric design of the double helical groove relative to the center and the intersection design of the middle and rear helical grooves have adverse effects on the hole position accuracy and the discharge of drill chips during drilling.

Due to the offset of the center of mass of the drill point, the asymmetric design is prone to deflection during drilling, and chip removal blockage is prone to occur in the blind groove, resulting in excessive cutting temperature and severe wear of a single main cutting edge

However, the helical groove intersection design in the middle and rear sections, the front end of the drill bit intersection is likely to be insufficient in rigidity, resulting in low hole position accuracy, and the chip removal at the intersection of the double grooves is likely to cause congestion, and the chips are not easy to discharge, which affects the processing quality of the drilling.

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