
In electronics manufacturing, retesting might seem harmless, even helpful. However, under the surface, its quietly draining time, budgets, and capacity and could represent future quality issues. The worst part? Most teams don’t even know it’s happening at scale.
This article unpacks why excessive retesting occurs, how much it could be costing you, the hidden issues and how smarter test data management can help you get control of your retesting.
We’ll also introduce the WATS Cost Analysis Tool, so you can uncover the real impact and start reducing retesting today.
Why most Manufacturers Retest more than Necessary
Retesting is deeply ingrained in many electronics manufacturing processes. And too fully avoid retesting is probably not obtainable.
However, it is a well-established fact that most electronics manufacturing companies retest their products more than what is ideal. It is a very familiar scenario for companies with outsourced manufacturing but also for OEM companies with in-house manufacturing.
Unfortunately, it is also a problem that also is almost invisible.
Whether driven by uncertainty, habit, or lack of visibility, the behavior tends to go unnoticed, and way to often until it’s too late.
Especially in outsourced setups or when test systems lack confidence from operators. Without data to back decisions, retesting feels like the safest move.
Overall Problems with Retesting
The consequence of retesting is both expensive and potentially damaging. Excessive retesting represents overall problems on a spectrum from less severe to more severe:
- Lost Test Capacity – Retesting ties up stations, reducing throughput
- Increased Costs – More operator time, more test equipment, more waste.
- Quality Risks – faulty units pass through after “pressure tricks” or repeated runs.
On the less severe end of the spectrum, the only consequence of retesting a product is that it takes time and steals bandwidth from the test throughput. It could be something as simple as the test operators’ impression that the test system itself is the source of the problems. If a test fails, it is only natural to test it repeatedly. Hoping that whatever problem they suspect will ease off.
Maybe the test limits are sat incorrect, and the average measurements are operating very close to one of the limits. Perhaps the operator suspects that there is poor connectivity from the test interface board, so he or she applies some force to the board. A trick they have picked up over the years has worked many times before. And behold, the product passes the test. Ready to move to the next stage. Or out to the customer.
When Retesting Becomes Concerning
You will find the exact same scenario on the more severe end of the spectrum. The product is failing. All of the accumulated experience of the test operator says that this is because of the test system. Retesting it is the obvious action to that. And again. And again. Apply some pressure, then test again.
The problem now though is that there is nothing wrong with the connectivity of the interface board. It is one of the capacitors that is not properly connected. As the test operator applies pressure to the system, the capacitance reaches just the right value to allow the unit to pass.
You would think that these scenarios are rare. You might think that the operators can distinguish between a faulty unit and a poor test system.
Our experience, working with several industry-leading companies in this sector is that this is far from rare. It happens all over the place, from high volume consumer electronics to FDA regulated products. They lack the insight provided by the Retesting Chart found in WATS. They simply lack the necessary data to bring the problem into the light.
You could think that implementing Forced Routing will fix this. But unless you have good control of your test systems accuracy it will most likely not fix the problem.
Estimate Your Retest Cost in Two Ways
The cost of retesting is an important metric in test data management and knowing your cost of retesting is vital if you want to improve. We introduce you to two ways of estimating this, one for non-users of WATS and the other one with the use of WATS.
Try the Retest Cost Calculator
If you are not using WATS yet you can start here and use our Retest Cost Calculator. This free calculator gives you a quick estimate of how much retesting might be costing you based on your own inputs.
Use the WATS Cost Analysis Tool
Already using WATS? Then you can track actual retest costs in real-time. Monitor trends, spot improvements, and tie results directly to manufacturing data.
Sign up for a free WATS Trial today, upload your data and use WATS to calculate the actual cost of retesting.
How to Fix and Transform a Retesting Culture
Fortunately, though, the two sides of the severity spectrum are very entangled. In simple terms, the common behavior is a tendency to deploy manufacturing test systems and not continuously optimize their accuracy. This in turn allows this undesired culture to manifest.
New Product Introduction is a golden opportunity to make this improvement, to ensure that your limits are well suited to the actual unit specification. But before the high volumes kick in. Before your focus shifts to other product releases.
In our top-down approach to quality assurance, the natural tool for this set of problems starts with Process Capability Analysis. In an early stage.
- Make sure that you don’t have big rooms for measurement outliers.
- That your measurements are not clustered towards one of the limits.
- And that when a product fails the test it is most likely a product issue.
Only then can you make sure that you have solid grounds to kill the retesting culture and stay ahead of the curve.
Ready to Rethink Retesting?
Retesting can eat up 10–30% of total test time. That’s a huge hidden cost, but also a massive opportunity. By reducing retesting, you free up capacity, reduce risk, and improve product quality. However reducing retesting isn’t just about saving time — it’s a strategic move.
With WATS you have full visibility into how many retests your products have. You can drill down and dissect this data as you need, to figure out what is the likely reason. If you collect repair data, you can cross-correlate these. You can either collect your repair data directly with our operator interface or use the Rest API to import the data. You can even receive automated notifications if products are retested more than a threshold.
With WATS, you can:
- See retesting rates and drill into root causes
- Correlate retests with repairs and product performance
- Get alerts when thresholds are crossed
- Ensure firmware and test software are always up to date
If you suspect that extensive retesting is a problem in your organization, make sure to sign up for a free trial to see what your test data looks like.