How To 7-9
7.3 Optimize a Program
After an initial test, you can adjust the following parameters to achieve optimum
performance.
7.3.1 Fill Time
• Ideally the fill time should be set so that, for a good component, no pressure
variation occurs during the stabilization phase; generally, a small variation is
acceptable.
• The fill time should be set to a period that is only long enough to ensure that the
test component is filled and holds the correct pressure.
• If the fill time is too short, the test pressure displayed during the stabilization
phase will either be lower than the set pressure, or will reduce during the
stabilization phase as the pressure equalizes within the component.
7.3.2 Stabilize Time
• The Stabilize time is the time that the instrument allows in order to achieve
pressure and temperature equilibrium in the test component before a reliable
leak test can be performed.
• Generally, increase the Stabilize time to reduce the leak rate measurement or
improve the repeatability of measurement.
• If the Stabilize time is too short, temperature effects or component expansion
may cause erroneous results during the test phase.
7.3.3 Measure Time
• The measure time should be set to give good discrimination between leak tight
parts and parts that only just fail the test criteria. For most applications, this
discrimination can be as little as 0.05 mbar, however for gauge R &R
compatibility and demanding applications, the test system should have a
resolution of at least 5% of the specified tolerance.
• Use the following to calculate the measure time from a chosen decay limit
(reject level):
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