Entry board for drilling small holes, a method of making the same and a method for drilling small holes through a printed circuit board by using said entry board
AssigneeShowa Aluminum Corporation
InventorsYasushi Washio, Koji Miyano, Akio Fukuda
Life of this patent
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Abstract
An entry board for drilling small holes having a front surface layer made of aluminum or aluminum alloy to be disposed at the drilling inlet side and a back surface layer made of aluminum or aluminum alloy to be disposed at the drilling outlet side. The back surface layer is adhered or joined by clad rolling to said front surface layer. The hardness of the front surface layer is smaller than that of the back surface layer.
Claims19
An entry board for drilling small holes, comprising:
- a front surface layer made of aluminum or aluminum alloy to be disposed at a drilling inlet side;
- and
- a back surface layer made of aluminum or aluminum alloy to be disposed at a drilling outlet side, said back surface layer being joined to said front surface layer;
- wherein hardness of said front surface layer is smaller than that of said back surface, and
- wherein said front surface layer and said back surface layer are flat and joined without any unjoined portion therebetween.
An entry board for drilling small holes, comprising:
- a front surface layer made of aluminum or aluminum alloy to be disposed at a drilling inlet side;
- and
- a back surface layer made of aluminum or aluminum alloy to be disposed at a drilling outlet side, said back surface layer being joined to said front surface layer by clad rolling;
- wherein hardness of said front surface layer is smaller than that of said back surface layer, and
- wherein said front surface layer and said back surface layer are flat and joined without any unjoined portion therebetween.
A method for making an entry board for drilling small holes, comprising the steps of:
- preparing an entry board having a front surface layer made of aluminum or aluminum alloy to be disposed at a drilling inlet side and a back surface layer made of aluminum or aluminum alloy to be disposed at a drilling outlet side, said back surface layer being joined to said front surface layer, wherein hardness of said front surface layer is smaller than that of said back surface layer;
- placing said entry board on a plurality of stacked printed circuit boards so that said back surface layer contacts said stacked printed circuit boards;
- and
- drilling said printed circuit boards.
A method for making an entry board for drilling small holes, comprising the steps of:
- preparing an entry board having a front surface layer made of aluminum or aluminum alloy to be disposed at a drilling inlet side and a back surface layer made of aluminum or aluminum alloy to be disposed at a drilling outlet side, said back surface layer being joined to said front surface layer by clad rolling, wherein a hardness of said front surface layer is smaller than that of said back surface layer;
- placing said entry board on a plurality of stacked printed circuit boards so that said back surface layer contacts said stacked printed circuit boards;
- and
- drilling said printed circuit boards.
An entry board for drilling small holes, comprising:
- a front surface layer made of aluminum alloy to be disposed at a drilling inlet side;
- and
- a back surface layer made of aluminum or aluminum alloy to be disposed at a drilling outlet side, said back surface layer being joined to said front surface layer;
- wherein hardness of said front surface layer is smaller than that of said back surface layer, and wherein a surface of said front surface layer is roughened such that central average roughness (Ra) is 0.15-0.30 .mu.m.
An entry board for drilling small holes, comprising:
- a front surface layer made of aluminum or aluminum alloy to be disposed at a drilling inlet side;
- and
- a back surface layer made of aluminum or aluminum alloy to be disposed at a drilling outlet side, said back surface layer being joined to said front surface layer by clad rolling;
- wherein hardness of said front surface layer is smaller than that of said back surface layer, and
- wherein a surface of said front surface layer is roughened such that central average roughness (Ra) is 0.15-0.30 .mu.m.
Dependencies are inferred from the claim text.