PURPOSE: To improve precision of perforation and to enable perforation machining without breaking a hole by providing a mechanism which blows air onto the surface of a die bush so as to suppress interference between the die bush and green sheet to the minimum in a machining process for forming a hole in the green sheet.
CONSTITUTION: When a punch 3 and a die bush 5 are coupled together to perforate a green sheet 6, the punch 3 is lowered downward to touch the green sheet 6. Then the punch 3 is inserted into the die bush 5 to form a hole. In this process, the die bush 5 and the green sheet 6 interfere with and bite into each other. When a hole is formed, the punch 3 is lifted in the direction of a cope 1 while the green sheet 6 is floated by a blowing force of air from an air jet nozzle 8 and transported by an X-Y table in this condition. Therefore, the green sheet 6 is not transported while biting into the die bush 5 and the hole is not broken.
SHIMIZU IZUMI
MIYAMOTO TAKUMI
HITACHI COMPUTER ELECTRONIC