TL;DR
Temperature non-uniformity during composite cure causes ply delamination or under-cure. Check thermocouple placement, recirculation fan speed, and door seal integrity before adjusting the cure profile.
What you might see
- thermocouple readings across the load span more than 5 C
- composite part fails porosity or delamination inspection
- one area of the load heats faster than the rest
- thermocouple readings near the door are lower than midpoint
Likely causes
Recirculation fan speed reduced from motor or drive fault
Door or access port seal leaking allowing cold air infiltration
Thermocouple placement on the part load violating the load survey procedure
Heater element failure in one zone creating a cold region
Required tools
- Calibrated type K thermocouples and data logger
- IR thermometer
- Masking tape for seal leak check
- LOTO kit
Safety first
- The autoclave operates at high pressure and elevated temperature. Follow the full ASC lockout procedure including pressure bleed-down before opening the door.
- Never open the autoclave door while pressure above zero is present on the gauge. A pressurized door can cause severe injury.
- High-pressure inert gas (nitrogen) used in some cure cycles is an asphyxiation hazard. Vent to atmosphere before entry.
Procedure
- 1
Review the cure cycle thermocouple data log and identify which thermocouple(s) showed the deviation.[1]
- 2
Verify the recirculation fan is operating at the specified speed. Check the fan motor current and VFD speed reference on the Econoclave control panel.[1]
- 3
Inspect the door seal and all autoclave penetrations for leakage. Apply a strip of masking tape over suspected areas and re-run at cure temperature, checking for tape displacement.
- 4
Lock out the autoclave and inspect the interior heater elements for any visible open circuits or burnt zones.
- 5
Verify all thermocouples placed on the load are in contact with the part surface, not floating in air pockets.
- 6
Run an empty temperature uniformity survey with a calibrated thermocouple array to establish the baseline autoclave performance before placing production parts.
Sources
ASC Process Systems ASC Econoclave Composite Autoclave general technical documentation, ASC Process Systems
ASC Econoclave operator and maintenance documentation, temperature uniformity survey procedures (general)
More guides for ASC Process Systems ASC Econoclave
How to fix pressure vessel seal leakage on an ASC Econoclave composite autoclave
Autoclave door or penetration seal leakage causes inability to hold cure pressure. Inspect and replace the door seal, check penetration fittings, and verify the seal groove is clean before pressurizing.
How to diagnose vacuum system faults on an ASC Econoclave composite autoclave
Vacuum loss during composite cure can cause voids and delamination in the finished part. Check the vacuum bag integrity first, then inspect the vacuum pump and lines if bag is intact.
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