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:
Jun. 20, 1989
Filed:
Mar. 30, 1987
Michael J Ankrom, Baltimore, MD (US);
Corey H Bowcutt, Annapolis, MD (US);
John J Buckley, Jr, Baltimore, MD (US);
James A Rew, Millersville, MD (US);
Westinghouse Electric Corp., Pittsburgh, PA (US);
Abstract
A method for vapor phase soldering components onto a PWB onto which solder has been previously deposited includes the steps of applying a fluxing agent on the PWB and introducing the PWB into a vapor phase environment. The application of flux is a multi-step process which includes a sequential application of flux to the PWB. The vapor phase environment defines 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.