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Pretinning PC Board by Immersion Method

IP.com Disclosure Number: IPCOM000040989D
Original Publication Date: 1987-Apr-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Mitchell, KR: AUTHOR [+3]

Abstract

Printed circuit (PC) boards can be pretinned with sufficient eutectic lead-tin solder by using an immersion solder pot.

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Pretinning PC Board by Immersion Method

Printed circuit (PC) boards can be pretinned with sufficient eutectic lead-tin solder by using an immersion solder pot.

The process follows the following steps: 1. apply flux to a bare PC board, 2. insert said PC board into a suitable holder, 3. immerse said PC board being held horizontally into a molten solder bath which is covered by a fluorinert so as to achieve enough solder attached to the solder pads by obtaining an appropriate dihedral angle through a force equilibrium condition, 4. use the motion of the edge of said PCB holder to sweep away the tarnished layer on top of the molten solder to guarantee the interaction between fresh solder and bare Cu pads, 5. lift said PC board vertically from the molten solder bath, 6. apply (hot) air-jet blower to remove excess solder and bridging and 7. clean said PC board.

This pretinning process can be used for hybrid component assembly if the PC board is designed in such a way that plated- through-hole components are assembled on one side and surface mount components are placed on the other side. Therefore, one can first mount plated-through-hole components and then turn to the other side to simultaneously pretin surface mount pads and solder plated-through-hole components.

Disclosed anonymously

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