The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 21, 1992
Filed:
Jul. 29, 1991
Applicant:
Inventors:
Morio Gaku, Tokyo, JP;
Hidenori Kimbara, Tokyo, JP;
Assignee:
Mitsubishi Gas Chemical Co. Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B23B / ;
U.S. Cl.
CPC ...
408 / ; 252 / ; 252 / ;
Abstract
A method of drilling a through-hole in a printed circuit board panel, which comprises placing a water-soluble lubricant sheet on one surface or each of two surfaces of a printed circuit board panel and drilling a through-hole through the printed circuit board panel, the water-soluble lubricant sheet being composed of a mixture of 20 to 90% by weight of a polyethylene glycol having a weight average molecular weight of not less than 10,000 with 10 to 80% by weight of a water-soluble lubricant and having a thickness of 0.05 to 3 mm.