Browse Prior Art Database

THERMALLY ACTIVATED ATTACHMENT MECHANISM

IP.com Disclosure Number: IPCOM000006821D
Original Publication Date: 1993-Mar-01
Included in the Prior Art Database: 2002-Feb-05
Document File: 3 page(s) / 104K

Publishing Venue

Motorola

Related People

Kurt Paquin: AUTHOR

Abstract

Surface mount devices depend on solder for mechan- ical stability. One cause of surface mount device failure occurs from solder fatigue due to mechanical stresses applied to the solder joint. The purpose of the Thermally Activated Attachment Mechanism is to solve the prob- lems associated with achieving reliable structural integ- rity of surface mount devices to printed wiring boards.

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INC. Technical Developments Volume 18 March 1993

THERMALLY ACTIVATED ATTACHMENT MECHANISM

by Kurt Paquin

   Surface mount devices depend on solder for mechan- ical stability. One cause of surface mount device failure occurs from solder fatigue due to mechanical stresses applied to the solder joint. The purpose of the Thermally Activated Attachment Mechanism is to solve the prob- lems associated with achieving reliable structural integ- rity of surface mount devices to printed wiring boards.

  All surface mount devices usually depend on at least two methods of mechanical attachment to a printed wir- ing board. Solder attachment only is one of these. The evident problem with this process is the result of relying upon solder for mechanical strength. This is not the pur- pose nor the intended use for solder due to its physical properties. The second method is the use of mechanical means for attachment. The conventional mechanical means usually consists of rivets, screws, and/or nut and bolt configurations. The conventional mechanical means actually will induce forces, and causes mechanical stress and solder fatigure to the solder joint of the surface mount device intended to be physically secured for stability, Elimination of the applied stress to the solder joints will improve the reliability and integrity of the surface mount device solder connections.

  The Thermally Activated Attachment Mechanism is inserted through an attachment means of a surface mount device and a hole or set of holes within the printed cir- cuit board during the conventional assembly process. The Thermally Activated Attachment Mechanism can become a permanent component of the surface mount device. This will allow for the automatic assembly of the surface mount device to the printed wiring board.

  The Thermally Activated Attachment Mechanism is composed of 2 components. A polymer lie material having a heat deflection t...