Method for vapor phase soldering
US4840305A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 30, 1987 |
| Grant date | Jun 20, 1989 |
| Priority date | — |
| Expiry date | Mar 30, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K2203/163
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.