| 摘要 |
A PCB micro drill comprises a drill body (1), at most three main cutting edges (212, 212', 221), and a composite drill tip (2) located at one end of the drill body. The composite drill tip comprises a first drill tip (21) and a second drill tip (22). The second drill tip is disposed at an end portion of the drill body. The first drill tip starts from the top end of the second drill tip and extends and protrudes outwards in the direction parallel to the central axis of the drill body. The first drill tip comprises a chisel edge (211) intersecting with the central axis of the drill body, an inner main cutting edge (212) connected to an end portion of the chisel edge, and a first inner vertex angle rear tool surface (213) clamped between the inner main cutting edge and the chisel edge. According to the micro drill, the drill tip is the composite drill tip consisting of the first drill tip and the second drill tip. The composite drill tip improves the centering effect of downward drilling during hole site machining for the PCB micro drill, improves the hole site accuracy, and prevents a failure in a hole site or a hole shape. |
