Cosmo LS-1866, Руководство по эксплуатации

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84 12 MAINTENANCE AND TROUBLESHOOTING
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12.5.1 When No-Go judgments occur consecutively
No-Go judgement Probable cause Treatment
Continuous
No-Go
Tested part
Internal mold cavity of the
tested part.
Leaks from sealing caused by
machining defects
Perform charge hold applying soap
solution on the sealing, and or
water-immersion test.
Volume change caused by
part and/or internal seal
deformation
Change the timer settings or test pressure.
Differential pressure due to
temperature changes
Let the part to be ambient temperature.
The sealing
fixture, tubing
or other parts
Worn-out or contaminated
sealing
Clean or replace sealing as required.
Leak from the tubing or
valves
Perform charge hold applying soap
solution on the tubing and valves
Differential pressure due to
seal volume changes caused
by clamping pressure
Implement exhaust interference prevention
to guard against effects from other testers
if any.
Review the sealing fixture and rubber
designs.
Temperature changes of the
fixture after water-immersion
Blow the water away and control the water
temperature.
Tester
Internal leak or contamination
of DPS
Perform No Leak test with the stop valves
closed.
Improper test timer
Execute Master-Preset sampling with
non-leaking part, and check if the value is
within the limit. If it is, extend timers.
Improper equivalent internal
volume
Perform leak calibration with a Leak
Master calibrated to specific leak rate.
Master-Preset
Compensation
Improper tested part (leak,
deformation or temperature
effects)
The part used for
Master-Preset value sampling
is not actual part.
Use actual non-leaking tested part for
sampling Master-Preset value.
When the BAL
stage completes,
the NG occurs.
Improper upper or lower limit test pressure Verify the upper and lower limit settings.
Large leak
After checking the sealing rubber for wear
or stuck foreign matter, replace with a
conforming tested part.
Improper test pressure
Check the pressure source.
Verify the regulator setting.
The
Master-Presetting
results in an NG
judgement.
Leak from the tested part, etc. Retry Master-Preset with another part.
Temperature change in the tested part
Do not carry out Master-Preset with a
special part, such as one that has just
been subjected to water-immersion
checking.
The judgement of
master NG
occurs frequently.
Leak from the master Replace the master.
Poor master temperature stability
Replace with a Master Chamber having
good temperature stability.