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Rework Fixture for Surface-Mounted Components

IP.com Disclosure Number: IPCOM000038977D
Original Publication Date: 1987-Apr-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Fry, B: AUTHOR [+4]

Abstract

The Multilayer Ceramic Surface Solder (MLCSS) is a ceramic component with up to 196 very high melt solder balls beneath it. The solder balls are attached to the card and to the component with solder paste that has a lower melting point than the solder balls. During a rework operation reflowing the solder beneath the center of the component that connects the card and the component to the high melt solder balls requires a special fixture, as shown in Fig. 1. The fixture mounts onto tooling already in use with a surface- mounted rework machine. The fixture features an inside and outside baffle to allow the hot air to be directed at the area requiring reflow without exposing the component to excessive and unnecessary heat. The head, as shown in Figs. 1 and 2, consists of four compartments through which air can flow.

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Rework Fixture for Surface-Mounted Components

The Multilayer Ceramic Surface Solder (MLCSS) is a ceramic component with up to 196 very high melt solder balls beneath it. The solder balls are attached to the card and to the component with solder paste that has a lower melting point than the solder balls. During a rework operation reflowing the solder beneath the center of the component that connects the card and the component to the high melt solder balls requires a special fixture, as shown in Fig. 1. The fixture mounts onto tooling already in use with a surface- mounted rework machine. The fixture features an inside and outside baffle to allow the hot air to be directed at the area requiring reflow without exposing the component to excessive and unnecessary heat. The head, as shown in Figs. 1 and 2, consists of four compartments through which air can flow. Two of these lines are used for hot air to come down and the other two for the hot air to go out. The outlets are in the opposite direction of the inlets, thus inducing hot air to flow underneath the components and heat the solder below. The bottom of the head is a high melt, but soft polymer, so that the head can be automatically rotated during rework operation to give a more even heating. The head distributes the heat evenly to each of the leads. Velocity control on the air can be used to increase the heat transfer coefficient between the air and solder.

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