Drilling apparatus for flexible sheet made of thick thermoplastic material

A drilling apparatus for flexible sheet made of thick thermoplastic resin material, comprising:

• a table containing a hole having a predetermined diameter at a drilling position thereof for said sheet;
• a drilling rod made of metal capable of rotating at high speeds while a rotation center line of said drilling rod reciprocating along a center line of said hole between inside of said hole and above said table;
• and
• a sheet pressing member disposed above said table and having an insertion hole for said drilling rod, said sheet pressing member being capable of approaching and leaving the surface of the table,
• wherein said drilling rod has smooth peripheral and front end faces composed of at least part of a circular section having no blade and wherein a predetermined clearance is provided between diameters of the hole and the insertion hole and a diameter of the drilling rod.