04203257 is referenced by 17 patents and cites 6 patents.

Multilaminate printed circuit boards have at least three conductor layers separated by two insulator layers. After drilling through the boards, cleaning of the drilled hole is accomplished by forcing a slurry of granular abrasive grit in a liquid carrier through the hole. Manifolds direct the slurry through the holes thereby cleaning them.

Title
Printed circuit board hole cleaner
Application Number
801936
Publication Number
4203257
Application Date
November 13, 1978
Publication Date
May 20, 1980
Inventor
Vincent A Masciello deceased
late of Rowland Heights
CA, US
William R Welty
Fullerton
CA, US
John W Jamison
Mission Viejo
CA, US
Agent
W H MacAllister
Allen A Dicke Jr
Assignee
Hughes Aircraft Company
CA, US
IPC
B24B 19/22
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