US 6,200,074 B1Granted

Method for drilling circuit boards

OwnerJames J. Miller, Paul E. Dinneweth +2inventors

InventorsJames J. Miller, Paul E. Dinneweth, Hans Vandervelde, James T. Hegeduis

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Abstract

A method and materials for drilling through-holes in printed circuit boards with a drilling tool is disclosed. The method involves the use of a lubricating entry material placed on the top surface of a stack of printed circuit boards and a lubricating backup board placed beneath the bottom surface of the stack of printed circuit boards. The lubricating entry material has a core with skins attached on both sides by a lubricant/adhesive. Similarly, the backup board has a core with skins attached on both sides by a lubricant/adhesive. The skins are hard enough to support the top and bottom surfaces of the printed circuit boards and thereby reduce burring at the entry point and exit point of the through-hole. The lubricant/adhesive coats the drilling tool during the drilling operation to reduce friction and thereby reduce the temperature of the drilling tool.

Claims33

Dependent claims

A method for drilling a stack of printed circuit boards, the stack comprising one or more printed circuit boards and having a top surface and a bottom surface, the method comprising the steps of:

a. placing an entry material adjacent the top surface of the stack of printed circuit boards wherein the entry material comprises:
i) a first hard outer entry skin placed adjacent the top surface of the stack of printed circuit boards;
ii) a first entry lubricant/adhesive layer separated from the top surface of the stack of printed circuit boards by the first hard outer entry skin;
and
iii) a second hard outer entry skin laminated to the first hard outer entry skin by the first entry lubricant/adhesive layer to provide dimensional stability to the entry material;
b. placing a backup board adjacent the bottom surface of the stack of printed circuit boards wherein the backup board comprises:
i) a first hard outer backup skin placed adjacent the bottom surface of the stack of printed circuit boards;
ii) a first backup lubricant/adhesive layer separated from the bottom surface of the stack of printed circuit boards by the first hard outer backup skin;
and
iii) a backup board core, attached on its one side to the first hard outer backup skin by the first backup lubricant/adhesive layer, for supporting the first backup lubricant/adhesive layer and the first hard outer backup skin;
and
c. drilling through the entry material, through the stack of printed circuit boards, and into the backup board.

9 more elements

Dependencies are inferred from the claim text.