In many automotive plants it’s the same story. A new leak detector is installed, parameters are tuned, calibrations are run, and the results are still inconsistent. Some good parts get rejected. Others pass when they shouldn’t. The R&R study shows too much variation. And the first reaction is usually to blame the instrument.
In many cases, though, the real problem is somewhere else: the sealing system used to connect the part during the test.
A leak detector can only measure what happens inside the part. If the connection or sealing system introduces extra leaks, movement, or variation, the results stop being reliable no matter what technology you use.
Let’s look at five common challenges that affect leak testing on the manufacturing floor every day.
1. Multiple open ports on a single part
Components like reservoirs, cooling systems, EV components, valves, or hydraulic assemblies can have several ports that must be sealed at the same time. Each additional port is one more opportunity to create a false leak.
When improvised plugs or connections designed for another application are used, variability rises considerably. The consequence is clear: more rework, more cycle time, and more false rejects.
The solution is to use connection systems designed specifically for each port and able to guarantee consistent repeatability over thousands or millions of cycles.
2. Tight spaces and difficult access
Many modern designs aim to reduce weight and size. That creates connections located in hard-to-reach spaces. It’s common to find ports near walls, connections surrounded by other components, or areas where a standard connection simply doesn’t fit.
When the operator has to “force” the connection to run the test, repeatability starts to deteriorate. A connection system designed for tight spaces can eliminate that variability and significantly reduce alignment problems.
3. High-pressure testing
The higher the test pressure, the more demanding it is on the sealing system. What looks like an adequate connection at low pressure can become a constant source of problems when you work with elevated pressures.
The consequences usually include connector blow-off, premature seal damage, intermittent leaks, and safety risks. For that reason, the connection system must be designed considering not only the part geometry but also the maximum working pressure.
4. Flexible tubing and deformable materials
This problem is very common in EV systems, medical components, hoses, rubber components, and plastic tubing. When too much force is applied during sealing, the material itself can deform. And when the part changes shape, the test result changes too.
The challenge is to achieve a tight seal without altering the geometry of the component. For these applications, solutions with internal supports or special designs that distribute the sealing load more evenly are typically used.
5. Thin-wall components
Some modern components are designed to reduce weight and material use. The problem is that a thinner wall is usually more sensitive to deformation during the test.
If the sealing system applies too much force, the part can deform, the internal volume changes, inconsistent readings appear, and the R&R study becomes unstable. In these cases, controlling sealing force is as important as choosing the right leak-test method.
The reality many plants discover too late
When a leak test has repeatability problems, the usual response is to check program parameters, regulators, sensors, and instruments. But the connection system is rarely reviewed.
The reality is that even the best leak detector on the market can produce poor results if the part isn’t sealed correctly.
What should an engineer look for when evaluating a sealing system?
Before designing or upgrading a leak-test station, it’s worth reviewing:
- Geometry of the test port.
- Maximum and minimum operating pressure.
- Expected number of cycles.
- Possible part misalignment.
- Component material.
- Accessibility for maintenance.
- Target cycle time.
- Repeatability and R&R requirements.
Conclusion
When a leak test produces false rejects, excessive variability, or repeatability problems, the instrument isn’t always the culprit. Often the root of the problem is the way the part is connected and sealed during the test.
Investing time in choosing the right sealing system can have a bigger impact than changing the instrument, reduce cycle times, and significantly improve the reliability of the entire inspection process.
At Lübeck we have the experience and technical capability to design and build custom sealing systems, tailored to each part’s characteristics, test pressure, cycle time, and quality requirements.
Because in leak testing there’s one rule that never changes: a measurement is only as good as the seal that makes it possible.