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Double-Dip Tinning Fixture

IP.com Disclosure Number: IPCOM000062676D
Original Publication Date: 1986-Dec-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Emerick, AJ: AUTHOR [+3]

Abstract

A fixture that holds substrates for immersion into a solder wave has a protruding wire to cut the solder surface such that the surface oxide does not interfere with the soldering. The fixture is used in the following manner. The fixture consists of a base 1 which is attached to a handle 2. Two substrate-holding brackets 3 are attached to the base 1 by means of tabs 4 which are attached to recesses 5 of base 1. A wire 6 is passed through holes 7 of bracket posts 8. A substrate 9 is mounted to the fixture when snapped into place between the posts 8 of the bracket. The substrate 9 rests on the wire 6. A thin leading edge of fixture serves to break the oxide surface of the solder when the fixture is immersed in solder. The thin leading edge is the wire 6.

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Double-Dip Tinning Fixture

A fixture that holds substrates for immersion into a solder wave has a protruding wire to cut the solder surface such that the surface oxide does not interfere with the soldering. The fixture is used in the following manner. The fixture consists of a base 1 which is attached to a handle 2. Two substrate-holding brackets 3 are attached to the base 1 by means of tabs 4 which are attached to recesses 5 of base 1. A wire 6 is passed through holes 7 of bracket posts 8. A substrate 9 is mounted to the fixture when snapped into place between the posts 8 of the bracket. The substrate 9 rests on the wire 6. A thin leading edge of fixture serves to break the oxide surface of the solder when the fixture is immersed in solder. The thin leading edge is the wire 6. The wire 6 has another thin leading edge on the other end of the wire 6 that serves to split the solder when the fixture is being withdrawn from the solder. The effect of the fixture is to allow the substrate 9 to enter and be retracted through clean solder. Dross and solder stringers are minimized or eliminated. A double-dipping procedure, immersing the substrate twice in succession without re-fluxing has the effect of providing a concave solder joint in recessed holes, e.g., pin heads that are recessed in the ceramic. The first dip provides a convex fill, and the second dip a concave fill. The concave fill facilitates the positioning of a chip on the solder pads reserved for the chip.

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