The customer saw the leaks on film
How do you locate a leak when there are 33 combinations that may be decisive? A process of elimination was out of the question – it would take far too long!
From manual to automated assembly
Karl Dungs – a gas regulator manufacturer – wished to optimise its production by automating its manual assembly lines. Not unexpectedly, various technical problems arose during implementation, and these were difficult to locate.
When regulators from the new assembly line were subjected to obligatory testing, far too many of them were found to leak. The rejection rate was too high.
Locate the problem – and solve it!
The problem was extremely complex, and interactions between several factors could not be ruled out. Dungs therefore decided to ask several of their subsuppliers to help solve the problem.
When a leak is identified, it is usually assumed to be caused by the seal. That is, of course, the obvious assumption. But in reality, it is very often not the case.
We were invited to a meeting with all the other suppliers and the staff of Dungs’ development, production and purchasing departments. The task was simple to define: Find the problem and solve it! The solution was, however, not so simple.
It must be a leaky gasket!
When a leak is identified, it is usually assumed to be caused by the seal. That is, of course, the obvious assumption. But in reality, it is very often not the case. The problem must be examined in its entirety – as a complete sealing system.
This is necessary because tightness depends on a wide range of factors other than the gasket – flange quality and surface roughness, for example. The quality of the bolts, and their number and location are also important, and factors relating to pressure, temperature and the medium can play a crucial role.
To achieve an optimum result, all components must be designed to support each other in producing a leak proof sealing system. If this is not the case, even the best gasket in the world cannot compensate for any shortcomings elsewhere in the system. This was the opinion we voiced at the meeting at Dungs’, where all eyes were focused on us – the gasket supplier! We were, however, convinced that the root of the problem was to be found elsewhere.
The hunt for leaks
After analysing the various components used in production, we discovered that the top of the regulator housing was not optimal. During assembly, excessive deflection of the top caused leaks.
Even though there was nothing wrong with our gaskets, we improved the product by contributing knowledge and expertise. And we succeeded ... We solved a crucial technical problem for Dungs in an economically sensible way.
We then examined the assembly line itself. And discovered that when the top was fitted, too much of the applied torque was used by the self-tapping screws to cut the thread. This meant that there was insufficient force to apply the correct surface pressure on the gasket. That was the second reason for leaks.
A revealing film
We proved our theories by inserting pressure sensitive film into the position of the gasket. Such film changes colour depending on the surface pressure exerted on it.
The film demonstrated that surface pressure was in fact only exerted around the boltholes. The greater the distance to a bolthole, the less tight was the gasket. As the arguments were logical and the evidence unmistakable, the factors we believed caused the leaks were changed. As a result, the rejection rate fell dramatically. Dungs’ objective was fulfilled!
Benefits and common interests
Even though there was nothing wrong with our gaskets, we improved the product by contributing knowledge and expertise. And we succeeded. For it is our know-how and expertise in combination with our extensive product range that make us a powerful business partner.
We solved a crucial technical problem for Dungs in an economically sensible way. We have also reaped the rewards. Our business with Dungs has increased and we have received our first sample order from their parent company in Germany.