Significant hermeticity failures occurred with electrical connectors that use circular stainless steel shell bodies, 9013-type sealing glass and Alloy 52-type pin contacts. A key design feature in the shell body is a 'd-flat,' which is used to orient the connector in next assembly, and which creates high unsymmetrical stresses. Significant technical requirements for the connector are that they be hermetic after 200°C temperature cycling and a set of thermal shocks. While this effort analyzed all processes involved, the majority of the effort was directed toward passivation, outgassing, pre-oxidation and sealing. Outgassing of the 304L alloy was determined to be unnecessary and was eliminated. Recommended design modifications, including a glass composition change and location of the sealing glass with reference to certain external shell features, were combined with the processes to be optimized. Using some of the Six Sigma Blackbelt evaluation tools, desired process working spaces were determined. The resulting process and design change improvements from these evaluations were implemented and qualified for production. This paper reviews some of the activities and evaluations performed to achieve an improved and robust hermetic seal under strenuous environmental conditions in electrical connectors with unsymmetrical bodies.
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