Patent ID: 8328473
Filing Date: 2012-12-11
Classification: B23B,H05K,Y10T

Abstract:
1. A drill for drilling piled copper plated laminate boards, comprising: a shank; and a body extending from an end portion of the shank, the body having a blade portion at a distal end of the body and a shaving discharge groove formed in the blade portion, wherein the shaving discharge groove of the body is formed in a one-stripe shape, the shaving discharge groove has a torsion angle which is in a range of 30 degrees to 50 degrees, the blade portion has a distal end angle which is in a range of 110 degrees to 150 degrees, the body has an occupying rate of a metal at a proximal end of a blade tip of the body in a range of 40% to 80%, and the groove has a curvature radius in an axially vertical direction of a deepest portion of the groove at the proximal end in a range of 1.50 mm to 3.50 mm.