TL;DR
Mold temperature non-uniformity causes partial under-cure or over-cure, leading to tread separation or crown cracking. Measure mold surface temperatures at multiple points and clean or replace blocked heating channels.
What you might see
- tires showing curing variation across the tread or sidewall
- mold thermocouple readings diverging between sectors
- steam condensate draining unevenly from the mold
- visible tread pattern variation in depth between sectors
Likely causes
Scale or deposit blockage in the mold heating channels reducing steam flow to one sector
Steam trap failed closed or failed open for a mold sector
Thermocouple failed for one mold sector giving incorrect temperature feedback
Mold segment steam supply valve partially closed or leaking
Required tools
- Contact thermocouple or IR thermometer
- Steam trap test tool
- Heat-resistant gloves
- LOTO kit for steam and hydraulics
Safety first
- Lock out the steam supply and the press hydraulics before accessing mold segments or steam traps.
- Steam trap discharge is at high temperature. Wear appropriate PPE and direct the discharge away from personnel.
- Heavy mold segments require mechanical lifting equipment. Do not manually handle mold segments without appropriate rigging.
Procedure
- 1
Lock out the press and allow the mold to cool before measuring or inspecting the heating channels.
Warning: Mold surfaces, steam lines, and mold segments are at temperatures above 170 C during operation and retain heat after shutdown. Allow adequate cooling time and wear heat-resistant gloves. - 2
Measure mold surface temperature at multiple points across all mold sectors with a calibrated contact thermocouple or IR thermometer after a cure cycle.[1]
- 3
Identify the cold sector by comparing temperature readings. A sector more than 5 C below the others indicates a heating deficiency.[1]
- 4
Inspect the steam trap for the cold sector. A steam trap failed closed blocks condensate from draining and prevents steam flow. Test the trap by checking the inlet and outlet temperature differential.
- 5
Verify the steam supply valve to the cold sector is fully open.
- 6
If all steam supply and traps are correct, suspect scale buildup in the internal heating channels. Descaling requires the mold to be removed from the press and chemically cleaned.
- 7
After correcting the deficiency, cure a tire and measure its uniformity properties to confirm the temperature correction is effective.
Sources
HF TireTech (HF Group) HF B-Series / TPB Tire Curing Press general technical documentation, HF TireTech (HF Group)
HF TireTech B-Series / TPB tire press maintenance documentation, mold heating system and temperature uniformity (general)
More guides for HF TireTech (HF Group) HF B-Series / TPB
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