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:
Mar. 20, 1990
Filed:
Oct. 14, 1988
Michael J Ankrom, Baltimore, MD (US);
James A Rew, Millersville, MD (US);
Westinghouse Electric Corp., Pittsburgh, PA (US);
Abstract
A method and an apparatus for depositing solder onto component lead pads of a printed wiring board. Solder preforms which are multi-layer, solder containing members are positively biased against the pwb pad which is then introduced into a vapor phase environment defining a temperature gradient between approximately ambient and the temperature of a saturated vapor of a first selected fluid which defines a primary saturated vapor phase with a boiling point which is greater than the melting point of solder. A second fluid having a boiling point which is lower than the first fluid is utilized to generate a secondary vapor blanket in order to prevent excessive loss of the fluid defining the primary vapor phase. The pwb is heated according to a controlled process in which the temperature of the pwb is continuously monitored. The apparatus is a pressure fixture usable for vapor phase solder deposition of a pwb and comprises a first and a second member which are removably fastened together in an opposed relationship with a pwb is disposed between the first and the second members.