| 摘要 |
PURPOSE: A hole processing apparatus for a multi layer board(MLB) is provided to laminate more boards rather than existing one and include a projection part on an inserting pin which assists to be inserted constantly into a board by using a short drill. CONSTITUTION: A projection part is formed on intermediate part of a pin, which diameter is 3.15 mm, to be coupled on a board which depth is 2.4 mm. A length of a drill is 5.3 mm and blade angle is 15 deg. A pressing tool is coupled to a plastic made auxiliary C ring. After processing 2 step holes placed on both sides of the board, the pin equipped with the projection part is inserted into them. Because of the projection part, the pin stops at certain depth. The drill is not distorted or damaged because of its short length, and process the hole easily with its moderate blade angle. During process of the hole, the pressing tool is protected from abrasion because of the auxiliary ring.
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