TL;DR
A burst or leaking curing bladder contaminating the tire interior or causing an abrupt pressure loss must be replaced before resuming production. Check the bladder for punctures or cut zones after every batch of tires showing inner surface defects.
What you might see
- bladder pressure drops abruptly during the cure cycle
- steam or nitrogen escaping at the mold parting line
- tires showing bladder marks or contamination on the inner surface
- curing controller shows bladder pressure alarm
Likely causes
Bladder puncture from a foreign object in the green tire or sharp mold feature
Bladder fatigue cracking from cumulative thermal cycles exceeding service life
Bladder center post connection loose allowing steam bypass
Bladder installed with incorrect clamp torque allowing it to unseat at pressure
Required tools
- Replacement curing bladder (matching press model and tire size)
- Torque wrench for clamp ring and center post
- Water tank or soapy water for leak test
- Heat-resistant gloves
- LOTO kit
Safety first
- Tire curing presses operate at pressures above 15 bar and temperatures above 170 C. Confirm zero pressure and allow mold cooling before opening the press.
- Steam exhaust from a burst bladder can cause severe burns. Stand clear when venting the cure circuit after a bladder failure alarm.
- Lock out the press hydraulics and steam / nitrogen supply before any work on the bladder assembly.
Procedure
- 1
Stop production and note the last tire cure cycle where the pressure dropped. Remove the partially cured or uncured tire from the press.
Warning: High-pressure steam and hot nitrogen are used in tire curing presses. The bladder and surrounding components are at temperatures above 170 C and pressures above 15 bar. Confirm the cure cycle is complete, all pressure is vented to zero, and the mold is cooled before opening. - 2
Open the press mold and remove the bladder assembly per the HF TireTech press service procedure.[1]
- 3
Inflate the removed bladder to a low test pressure (2 to 3 bar) in a water tank or with soapy water to locate the leak point.[1]
- 4
Inspect the full bladder surface for cuts, punctures, or fatigue cracking. If any damage is found, the bladder must be replaced.
- 5
Inspect the bladder center post and clamp ring for deformation or thread damage.
- 6
Install the replacement bladder following the HF TireTech installation procedure. Torque the clamp ring and center post to the specified values.
- 7
Run a pressure test cycle at full cure pressure before loading the first tire to confirm the new bladder is sealed.
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 operator and maintenance manual, bladder inspection and replacement (general)
More guides for HF TireTech (HF Group) HF B-Series / TPB
How to correct clamp ring misalignment on an HF TireTech B-Series / TPB tire press
Clamp ring misalignment causes flash at the tire parting line and can damage the mold. Verify the ring actuator positions and mold segment alignment before re-clamping.
How to fix mold temperature non-uniformity on an HF TireTech B-Series / TPB tire press
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.
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