ALT of Lead Free CCAs
• Provide background on the impact of lead free versus conventional solder on the life of a circuit card assembly (CCAs)
• Illustrate through comparison of results of a Highly Accelerated Life Test (HALT) on two of the same CCAs, but four (4) lead free and four using conventional solder
• Demonstrate how a MTBF comparison can be achieved by Accelerated Life Test (ALT) planning for two similarly populated CCAs: lead free versus conventional solder
• Consumer Products warehoused in Georgia experienced insulation degradation
• Actual degradation, remaining insulation life if damaged and expected life of undamaged insulation all needed evaluation
• The product in question: a thermoplastic polyurethane (TPU) but unknown if it is ester or ether based.
A Leading Indicator enables better life test and prognostication
Arthur Zingher, Physicist, Senior Reliability Engr.
Mike Silverman, Founder, Managing Partner, CRE
During life test, how to further reduce (“accelerate”) test time and to provide earlier & richer feedback. During normal operation, how to use a leading indicator to prognosticate future failures, to sharpen maintenance, to improve system reliability. This describes a mechanical example, but these concepts are more widely applicable.
To ALT or Not to ALT: A Case Study
Mike Silverman, OPS A La Carte
Paul Parker, Lineage Power
Perhaps the most critical aspect of an Accelerated Life Test is fully understanding the failure mechanism before going into the test. If we don’t understand this, we will likely apply the wrong type of stress and calculate the acceleration factor incorrectly, and therefore, we will come to the wrong conclusion. But if we take this extra time, we may find that we can find what are looking for based on analysis, and running an ALT is no longer even necessary. The following is a case study of such an event.