Browse Prior Art Database

Deburring Drilled Holes

IP.com Disclosure Number: IPCOM000073471D
Original Publication Date: 1970-Dec-01
Included in the Prior Art Database: 2005-Feb-22
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Antonucci, RF: AUTHOR

Abstract

Burrs 1 remaining in copper layer 2 after drilling of holes 3 in printed circuit stock 4 are removed by the following procedure. First uniform layers 5 of specific liquid resist material are formed on both sides of the card. The resist material is prepared to have a condition of viscosity causing it to flow away from sharp contours on the card surface. After processing the resist layers to an etch resistant state the assembly is exposed to an etching agent sufficiently active to remove the burrs, and conveniently, to smooth edge contours at the hole.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 2

Deburring Drilled Holes

Burrs 1 remaining in copper layer 2 after drilling of holes 3 in printed circuit stock 4 are removed by the following procedure. First uniform layers 5 of specific liquid resist material are formed on both sides of the card. The resist material is prepared to have a condition of viscosity causing it to flow away from sharp contours on the card surface. After processing the resist layers to an etch resistant state the assembly is exposed to an etching agent sufficiently active to remove the burrs, and conveniently, to smooth edge contours at the hole.

A resist preparation useful in the foregoing procedure includes a 1:1 mixture in solution of Shipley AZ111 photoresist and Ethyl Acetate. It is applied conveniently by spraying from a Zicon sprayer having the following settings. a) Index setting: 2 b) Pass setting: 7 c) Speed setting: 70-75.

After the resist is sprayed on one side of the card the card is kept in a horizontal position and baked for 10 minutes to harden the sprayed film. Baking temperature is in the range 170 degrees-180 degrees F. Upon cooling the other side of the card is sprayed and the horizontal baking step repeated. After etching in a ferric chloride etcher the resist films are removed in a stripping solution.

The card is then coated with conductive plating 6.

1

Page 2 of 2

2

[This page contains 1 picture or other non-text object]