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Tube Propelled Jet Solder Fountain

IP.com Disclosure Number: IPCOM000048563D
Original Publication Date: 1982-Feb-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 3 page(s) / 78K

Publishing Venue

IBM

Related People

Baron, PL: AUTHOR [+4]

Abstract

The use of conventional piston-driven solder fountains is limited by the availability of a fixed volume of solder. As a consequence, heat transferred to the card is slow and restricted. Thus, the removal of large modules becomes quite difficult.

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Tube Propelled Jet Solder Fountain

The use of conventional piston-driven solder fountains is limited by the availability of a fixed volume of solder. As a consequence, heat transferred to the card is slow and restricted. Thus, the removal of large modules becomes quite difficult.

Existing continuous flow fountains require a large amount of solder to operate, making it expensive to replace the solder when contamination limits are reached. In addition, their design is such that the impeller is located at angles of 90 degrees, or more, to the chimney axis. These factors combine to limit the volume of solder reaching the chimney, thus making it ineffective, and to create excessive dross and loss of solder. When using expensive, low melting alloys, the resulting large amount of solder and excessive dross formation under the use of this type of fountain is prohibitive.

A concept is proposed which allows for an unlimited volume of solder to be brought in contact with the card at any desired rate, thus providing an infinite heat source for component removal. The fast heating rate allows the solder joint to reach the liquidus temperature before the heat has had time to propagate to the module, thus enabling the removal of large modules in a very short time with less copper dissolution, no card delamination, and lower component temperature. This concept also reduces machine maintenance to a minimum since the absence of the piston/cylinder combination eliminates friction and piston binding which is the major source of trouble in solder fountain operations.

Approximately 9 lbs. of solder are melted in a conventional solder pot 1. The tube-propelled jet mechanism 2 is standing upright in the center of the solder pot. Its lower end protrudes through the bottom of the casting and is held in posi...