| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a condition for drilling a hole of an excellent quality in a material having a low melting point like a foamed PET material.SOLUTION: In work for drilling a material of a melting point of 300°C or lower by using a drill having a diameter of 0.2 mm to 0.4 mmφ, a drill may have a point angle of 130 to 140°, a twist angle of 40° or more, core thickness of 0.04 to 0.06 mm, a groove width ratio of 3, a web taper of 1.5 or less, the internal diameter of a point bush of 1.2 mmφor less, a lubricant-coated aluminum plate as a finish plate, and a cutting speed of 3.5 m/min or higher.</p> |
