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:
Feb. 23, 1993
Filed:
Jan. 28, 1991
Kirk E Johnson, Diamond Bar, CA (US);
Edward Modzelewski, Chino Hills, CA (US);
Hughes Aircraft Company, Los Angeles, CA (US);
Abstract
An improved process for the fusing a tin-lead solder mixture deposited to form a finished circuit on a printed circuit or wiring board. The method comprises the rapid or flash fusing of the circuit board having the tin-lead solder mixture deposited thereon by immersing into the vapor of an inert fluid having a boiling point just above the melting point of the solder alloy. Problems with 'weak knee' conditions are avoided by adjusting the heating time-at-temperature to that which allows the desired tin-lead solder alloy to form only as a thick 'mush' rather than as a molten fluid. By so doing, the solder alloy is formed without the necessary degree of fluidity that causes it to draw away from the edge or rim of plated holes in the board.