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:
Dec. 31, 1985
Filed:
Sep. 04, 1984
Kenneth N Abel, Vista, CA (US);
Gerald R Dunn, Carlsbad, CA (US);
Burroughs Corporation, Detroit, MI (US);
Abstract
A method is disclosed for removing an integrated circuit package that has multiple leads which are soldered into respective metal plated holes in a printed circuit board. The board is of the type that has internal metal lines which make joints with the metal plating, and the method is adapted to remove the package from the board without overstressing the joints. The method includes the steps of: flowing a liquid on the leads at a temperature higher than the melting temperature of the solder without pulling on the package for a time period .DELTA.t.sub.1 ; and pulling on the package immediately after the end of the .DELTA.t.sub.1 period with a force F.sub.1 =F.sub.3 +(25 to 75)% F.sub.2. Force F.sub.2 is the minimum force that will extract a single soldered lead from the board under the condition the solder is below but within 5.degree. C. of melting; F.sub.3 is the minimum force that will lift the package from a pool of the liquid; and .DELTA.t.sub.1 is the time it takes to pull the package from the board with force F.sub.1 being continuously applied while the liquid is flowing on the package leads to melt the solder plus one to three seconds.