Case study from automotive electronics Unnoticed Changes to Electronic Assemblies as the Cause of Series Failures
When proven electronic assemblies suddenly start to fail, the root cause is not always found in the company’s own production process. A practical case from automotive electronics shows how ZESTRON identified the actual cause of failure and derived concrete assistance modules from the findings.
— Failure mitigation Correctly Assessing Unexpected Series Failures
An automotive radio experienced severe functional failures in a mechanical rotary switch. Initially, corrosive gas exposure was suspected. However, the analysis revealed a different cause: a change in the lubricant that had not been transparently communicated.
From visible failure symptoms to a reliable root cause
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Systematically narrow down potential failure causes
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Derive concrete corrective measures for series production and supply reliability
Are you facing a similar failure case?
Briefly describe your failure symptoms. ZESTRON supports you in identifying potential causes and deriving suitable corrective measures.
— The ChallengeSudden Failures Despite a Proven Component
A manufacturer of automotive electronics was confronted with a rising number of customer complaints. The issue affected a specific mechanical rotary switch used in a series product. The component had been in use for years and had not previously shown any abnormalities.
The failure pattern was clear: the control could still be operated without any issues in one direction, but malfunctions occurred when it was turned in the other direction. For the manufacturer, this created an acute risk in terms of quality, delivery capability, and potential field actions.
It was also noticeable that the complaints were reported mainly from regions with warm climates and polluted ambient air. The initial suspicion was therefore obvious: corrosion caused by harmful gases could be impairing the function of the component.
— Analysis and TroubleshootingTracking Down the Failure
Why the First Assumption Is Not Always the Right One
When electronic assemblies fail, a plausible failure pattern can quickly lead to an initial hypothesis. This is important, but it should not be accepted prematurely as the final root cause.
In this case, the first step was to examine whether corrosive gases had attacked the contact or functional surfaces of the rotary switch. However, a detailed investigation using suitable tests did not confirm this suspicion.
It was therefore clear that the cause had to lie deeper. ZESTRON continued the analysis and compared functioning components from earlier series with affected components from the new production batch.
The Analysis Revealed an Unnoticed Material Change
The direct comparison provided the decisive clue: a modified lubricant had been used in the new rotary switch.
This change was not initially apparent to the manufacturer. However, the new lubricant was not sufficiently suitable for the actual operating conditions. At elevated temperatures, it aged more quickly and changed its consistency. As a result, the rotary switch was mechanically impaired, which became noticeable during operation as a functional failure.
The root cause of the failure was therefore neither classic contamination of the electronic assembly nor corrosion caused by harmful gases. The decisive factor was a material change within the supply chain that had not been adequately assessed.
— Solution ApproachConcrete Corrective Measures Instead of a Mere Failure Description
For the customer, identifying the root cause was only part of the challenge. The key requirement was to quickly derive a technically sound solution.
Based on the analysis, the lubricant could be specifically evaluated and replaced with a more ageing-resistant variant. This reduced the risk of further failures and helped safeguard the function of the component under the relevant operating conditions.
This case shows that failure analysis does not end with describing a failure. The decisive next step is to translate the analysis results into concrete measures for the product, process, or supply chain.
This case study shows how unnoticed changes to components, materials or suppliers can lead to unexpected failures in series production. For comparable failure patterns, ZESTRON supports the technical assessment, the evaluation of relevant influencing factors and the derivation of suitable remedial measures.
Unnoticed changes to components, materials, or auxiliary materials can have a significant impact on the reliability of electronic assemblies. This applies not only to cleaning processes or surface contamination, but also to mechanical components, coatings, lubricants, plastics, potting compounds, and supplier materials.
Changes that are not communicated in time or not evaluated under realistic operating conditions are particularly critical. In series production, they can lead to customer complaints, production stops, additional testing effort, or recall risks.
For manufacturers and suppliers, this raises key questions:
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Which component or material changes have been made within the supply chain?
Were these changes evaluated against the actual operating conditions?
Does the initial failure hypothesis really match the failure pattern?
Which tests are required to reliably narrow down the root cause?
Which corrective measure will reduce the risk in the long term?
ZESTRON supports companies when electronic assemblies, power modules, or individual components fail unexpectedly, do not pass qualification tests, or show abnormalities in the field.
In doing so, we look beyond cleaning and contamination. Depending on the failure pattern, we also examine material changes, environmental influences, supplier changes, component properties, surface conditions, and process risks.
Our support includes:
- structured failure analysis for field returns, qualification failures, and series production issues
- identification of plausible failure mechanisms
- testing and evaluation of components, materials, and surfaces
- comparison of affected and unaffected batches
- derivation of concrete corrective measures
- support in technical communication with suppliers
- risk assessment for series production, release, and continued manufacturing
The goal is not only to clarify the root cause. The goal is to provide a reliable basis for decision-making that helps reduce quality risks, safeguard delivery capability, and prevent recurring failures.
An independent root cause analysis is particularly helpful when several influencing factors are possible and internal testing does not provide a clear answer. ZESTRON combines analytical methods, experience from real failure cases, and technical understanding of electronic assemblies, materials, and operating conditions.
This provides companies with:
- a traceable assessment of the failure mechanism
- greater certainty when evaluating supplier changes
- reliable arguments for internal and external coordination
- concrete technical corrective measures
- reduced risks of complaints, delivery stops, and field actions
- a stronger basis for future specifications and test requirements
— assistance modulsRisk Assessment of Electronic Assemblies
Unnoticed changes to components, materials or auxiliary materials can affect the reliability of electronic assemblies long before they become visible in final reliability testing.
In our assistance module Risk Assessment of Electronic Assemblies, we evaluate how quality testing methods can be used before final reliability tests such as PPAP and PA. Instead of relying only on pass or fail results, these methods help identify safety margins, reveal hidden weaknesses and support targeted product and process improvements.
The module is tailored to the specific questions and challenges of your project. It helps you assess technical risks, evaluate relevant influencing factors and define precise measures for your individual requirements.
— Whitepaper CollectionIdentify and Avoid Causes of Damage
Malfunctions and field failures in electronic assemblies cannot always be explained by the first obvious hypothesis. What is decisive is a systematic root cause analysis that considers the failure pattern, components, materials, process conditions and possible influencing factors in context.
The whitepaper uses a practical case study to show how root cause analysis for malfunctions and field failures can be applied in practice, and how concrete approaches for identifying the cause and deriving suitable remedial measures can be developed from the analysis.
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