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Necessary duration of test cycles

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Of course, efforts to keep the cycles as short as possible.This must, however, ensures that the test results the appropriate test reliability (see also the capability study) have. Cycles are too long, possibly to use a separate testing station operating in parallel may be necessary. The more expensive of course, the entire inspection system and ultimately the product being tested.

A complete test cycle in leak test and flow test systems is always much the same principle:

  • Filling of the test volumen by the nominal test pressure (filling phase)
  • Wait until all transient processes are completed (calming phase)
  • Finding the leak by means of differential pressure and mass flow processes (measurement phase)
  • Issue and evaluate the results
  • Venting the test volume (exhaust phase)

The duration of each phase depends very much on the test conditions. These include, for example:

  • The required test pressure
    In general, the test cycle with increasing pressure is a little longer, because here the compensation processes in the test gas (air) may take longer.
  • The required limit leakage
    To obtain a stable process, must be achieved a reproducibility, which is less than 10% of the marginal leakage. However, since all measurement systems (sensors) have a finite resolution, one can only reach by extending the measurement time to produce the desired results. Under certain circumstances, eg one is forced to specific inspection tasks that come too close to reality by a different approach.
  • The examined test volume
    The volume structure (surface, material, etc.) also contribute, as long as the filling, comforting and measurement phase should be interpreted. Simple cavities usually require longer cycles than a jagged hole system. Also, metal parts behave differently than plastic parts.
  • The possible influence of temperature
    Each temperature control during test affects the final result. Here it is to check, that you see an constant influence. This mostly is easy to compensate. Otherwise it may be necessary to use a temperature compensation system.

APT has a long experience in the field of leak and flow test. The best way is therefore to give the entire test APT known. We then choose the appropriate test system for the inspection task with the necessary accessories for our customers and deliver targeted at the corresponding site.