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:
Apr. 30, 1991
Filed:
Dec. 06, 1989
Masao Nishigai, Ayase, JP;
Tamio Otani, Hadano, JP;
Yasuhiko Kanaya, Machida, JP;
Tetsuo Murakami, Atsugi, JP;
Hitachi Seiko Co., Ltd., Tokyo, JP;
Abstract
A method of machining the contour of a printed circuit board by effecting a relative feed movement between a rotating tool and the other periphery of the printed circuit board. The electrical current value of a drive motor for driving a spindle to which the tool is attached is detected and an operation is conducted for changing the machining condition in such a manner as to reduce the electrical current value of the spindle drive motor and, at the same time, for changing also tool diameter compensation amount to a value corresponding to the machining condition after the change, at every time the detected electrical current value has reached a predetermined current value immediately before tool breakage and repeatedly by a predetermined number of times.