Browse Prior Art Database

Connector Solder Joint Flaw Detection Measurement Apparatus

IP.com Disclosure Number: IPCOM000079620D
Original Publication Date: 1973-Aug-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Pivnichny, JR: AUTHOR [+2]

Abstract

A flat wire bus (FMB) connector makes electrical contact with the bus through a wide solder joint 10, between the flat copper material 11 of the bus and a beryllium-copper carrier strip common to the tuning-fork contacts 12. After assembly of the connector housing 13, the solder joint 10 is hidden from view.

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Connector Solder Joint Flaw Detection Measurement Apparatus

A flat wire bus (FMB) connector makes electrical contact with the bus through a wide solder joint 10, between the flat copper material 11 of the bus and a beryllium-copper carrier strip common to the tuning-fork contacts 12. After assembly of the connector housing 13, the solder joint 10 is hidden from view.

Poor control of the soldering process is from time-to-time responsible for producing a large proportion of solder joints with short cracks, located near the ends of the carrier strip where the mechanical and thermal stresses are concentrated. Although these cracks do not initially impair the electrical current supply function of the FWB in a machine during initial test, they propagate along the joint over a period of time causing the entire solder joint to eventually fail, resulting in a machine failure. Typically, many connector housings are assembled over poor joints before the process problem is discovered. It is prohibitively expensive to open the housings in order to examine the solder joints. An electrical test to be described is used to detect such solder flaws prior to the time the FWB is installed in a machine, thereby preventing subsequent machine failures because of solder joint failure.

The cracks are detected by a technique involving a four-point resistance measurement, making use of the four outer tuning forks 12 of the strip of contacts, as shown. The outermost tuning forks 12 are the...