| 摘要 |
PURPOSE:To prevent melting slag from attaching to the inside of concave grooves as produced during the piercing by running a resin film between a heating roll with a plurality of piercing projections and a cooling roll with the concave grooves arranged on the circumference thereof corresponding to the projections prior to the piercing. CONSTITUTION:A heating roll 4 provided with a plurality of piercing projections 3 along several circular lines 2 at the right angle to the axis thereof and a cooling roll 8 provided with concave grooves 6 in such a manner that the projections 3 are free to be inserted removably thereinto for each of ring-shaped lines 5 corresponding to the lines 2 are arranged on insertion shafts 9 and 10 with the concave grooves 6 corresponding to the projections 3. The space is set between the shafts 9 and 10 according to the thickness of a resin film 17 and the diameter of a hole 18 to be pierced. The roll 4 is heated up to 200-400 deg.C while the roll 12 cooled below 20 deg.C. Then, a film 17 is inserted between rolls 8 and 4 both along the lower outer surface 13 of a cooling feed roll 12 and the upper side of the roll 8 to pierce. Then, it is pulled out along the lower circumferential surface 7 of the roll 8 and wound up with a winding roll 15. |
