Tire Building Machine Shutdown & Restart Procedure: TBR Workshop SOP

Every tire factory faces planned and unplanned stops — holidays, equipment breakdowns, or mold changes. How the building workshop handles green tires, semi-finished components, and solvents during a shutdown directly determines whether restart production launches cleanly or emerges with a wave of adhesion failures and scrap. This is the standard procedure used in an all-steel TBR tire workshop.

Keywords: tire building; tire factory shutdown; green tire storage; semi-finished component; tire production restart; TBR tire; tire manufacturing SOP

Purpose and Scope

This procedure governs orderly shutdown and restart of the tire building (forming) process, covering semi-finished components, green tires, and raw materials. The production shift leader is the first point of contact; the quality process-inspection foreman handles quality decisions.

Before Shutdown: Line Clearance

At the end of production before a stop, the semi-finished goods workshop must collect all leftover components on the line. On restart, every tire remaining on conveyor rolls, tire stops, or transfer belts must be sent to QC for inspection before further processing.

Shutdown ≤ 5 Days

Cement and Gasoline

• Minimize on-hand stock of all rubber cements and gasoline.
• Cover all containers, label them, and store properly.
• Move all flammable materials to the fire-proof room or return them to the designated storage area.

Building Area

• Minimize green tire inventory. Remaining green tires must be placed in green tire trays to prevent deformation.
• All belt plies, carcass plies, sidewalls, and shoulder pads loaded on building machines must be rolled back and stored in designated process-compliant areas.

Curing Area

All green tires must be stored in green tire trays.

Shutdown > 5 Days

• All shaped semi-finished components and rubber sheets must be returned for reprocessing.
• All cut reinforcement materials (cord plies, bead wire rings, etc.) must be scheduled into production and fully consumed before the shutdown begins.

Restart Procedure

Semi-Finished Components

If the assembled bead assembly shows blooming on the rubber core:

1. Separate the rubber core from the bead wire ring.
2. Return the rubber core for blending per standard rules.
3. Coat the bead wire ring with cement and put it back into service.

Building Machine

Check the tackiness of reinforcement semi-finished components before use:

• Normal tack: use directly.
• Poor tack, no blooming: wipe with gasoline.
• Bloomed surface: wipe with gasoline first, then recoat with cement.
• Mixing rule: adjacent components on the same tire must alternate between treated and untreated material, ensuring adequate inter-component adhesion.

Documentation and Escalation

• Every component requiring disposition gets a disposition card from the semi-finished workshop. The producing workshop inventories and records all items, and passes the list to Quality and Engineering.
• Before reuse, try to confirm the original production status. The building workshop records every dispositioned component used — component code, production date, green tire number — on the back of the machine verification log.
• If defect rate on dispositioned tires exceeds 20%, stop all dispositioning immediately.

Key Takeaways

1. Short stop (≤5 days): cover solvents, tray the green tires, roll back machine-loaded components.
2. Long stop (>5 days): return all shaped components; burn off cut reinforcement stock before shutdown.
3. Restart: inspect tack, treat bloomed surfaces (gasoline + cement), alternate treated/untreated parts on the same tire.
4. Hold the line at 20% defects: any higher scrap rate on dispositioned material and the process stops until engineering reviews.

Non-Conforming Product Handling in Tire Manufacturing: Raw Materials, Compounds & Semi-Finished Goods

A formal disposition process for non-conforming materials is essential to reduce waste while preventing defective tires from reaching the market. This standard operating procedure covers how tire factories handle out-of-spec raw materials, compounds, and semi-finished components — from inspection failures to in-use defects.

Keywords: tire manufacturing; non-conforming product; quality control; compound rejection; raw material rejection; tire factory; scrap management; rework

Scope and Responsibility

This procedure applies to all incoming raw materials, auxiliary materials, mixed compounds, and semi-finished components. Non-conforming raw and auxiliary materials are reported to the Technical Department via a tracking record. Non-conforming compounds or semi-finished goods are reported via a disposition form. The Technical Department maintains this standard; individual plants write their own detailed rules.

1. Raw and Auxiliary Materials

1.1 Non-Reinforcement Compounding Materials

Issue	Disposition
Failed incoming inspection (except NR)	Return or exchange. Visual defects may be trialed depending on production needs. Materials with no national/industry standard may be trialed.
Natural rubber failed inspection	Return/exchange normally. Visible impurities → per clause below. Water droplets, mold, ash/volatiles/nitrogen out of spec: blend with good batches at ≤1:1 ratio. P0/PRI out of spec: blend at ≤1:4 ratio.
Impurities found in use	Easy-to-remove impurities → observe and use. Metal impurities in NR → return entire lot. Non-metal impurities in NR → sample at least 3 pallets; if any pallet has >30% contaminated blocks, return entire lot. If all ≤30%, blend at ≤1:1 in truck tread (non-OE) compounds.
Agglomerated small chemicals	Resins, accelerators, sulfur, antioxidants, rosin, bitumen: crush if possible, remove hard lumps, use normally. ZnO/MgO lumps → return. Liquid materials (oils, silane, release agents) with separation/sediment → return.
Supplier repeat failures	Two consecutive failures or >3 per year: warning if minor impact; suspension with corrective action report if severe impact.

1.2 Reinforcement Materials (Cord, Wire, Fabric)

Issue	Disposition
Critical property failure (cord breaking force, steel cord breaking strength)	Return entire lot. Non-critical properties may be trialed after review meeting.
Packaging damaged in transit, inner packaging intact	May be trialed based on production needs.
Short bobbin length causing excess scrap	Supplier bears the scrap cost.
Wrong cord规格 mixed in calender batch	Must be sorted out; supplier bears loss. Remaining uncalendered cord returned/exchanged.
Excessive residual twist causing cutting curl/splice difficulty	Manual splicing allowed; supplier bears cost.
Calender skipped/loose cords due to cord twist issues	Must be sorted; supplier bears cost.
Bead wire: broken strands, loose bundles, knots	Return/exchange. Hard bends or broken welds: cut out and continue; notify supplier.
Cord fabric: broken warp, splits, paste spots	Return. Paste spots ≤1.5 cm² each, <40 per roll; continuous warp sticking ≤5 m, max 5 per roll. Exceeding limits → return.

1.3 Process Auxiliary Materials

• Curing/bladder capsules: Return on incoming failure. Off-center, aged, cut, internal cracks, or blisters → replace immediately and file supplier claims. Engineering tire capsules <80 cycles → claim one capsule; other capsules <200 cycles → claim proportionally.
• Tire barcodes: Return/exchange on failure; peeling labels → exchange. Three failures in one year → 3+ month suspension.
• Tire labels: Return if unusable. Minor deviation (≤10%) → concession use at reduced price. Peeling/unclear → exchange.
• Release agents, inner spray, finish liquid: Return on failure. Poor lubrication causing wrinkles/traps → return with defective tire samples for claim. Clogged spray guns → return.
• Winding fabric (liner): Thickness/appearance issues may be trialed. Delamination, peeling difficulty, or breakage → return; notify supplier for corrective action.

2. Rubber Compounds

2.1 Mastication Compounds

Issue	Disposition
Incorrect peptizer, mixing cycle, or equipment issue	Downgrade; blend with normal mastication at ≤1:1 in subsequent mixing.
Sand, wood chips, iron debris found	Remove debris; downgrade; blend at ≤1:1 (never for inner liner compounds). Filter the mixed compound and thin-pass if needed.
Undispersed raw NR lumps	Downgrade, scrap, or return depending on severity.
Different grades mixed together	Downgrade to the lower grade.
Expired mastication compound	Blend with normal at ≤1:1.

2.2 Masterbatch Compounds

Issue	Disposition
Missing/under-dosed ingredient (non-polymer)	Rework per process; blend with normal at ≤1:2 in subsequent batches.
Over-dosed ingredient	Blend at ≤1:2 or scrap depending on severity.
Process/equipment anomaly	If extruded sheet looks normal: blend at ≤1:2. If abnormal: isolate, blend, or scrap.
Expired masterbatch	Normal appearance: blend at ≤1:2. Abnormal: isolate and decide.
Two masterbatches mixed	Isolate; blend at ≤1:3 or scrap.

2.3 Final Mix Compounds

Issue	Disposition
Wrong masterbatch type used	Isolate; blend or scrap.
Wrong curative type	If quick test passes: blend at ≤1:2. If fails: follow compound management rules.
Wrong curative amount	Isolate; blend at ≤1:3 or treat as return compound.
Two compounds mixed	Isolate; blend at ≤1:3 or scrap.
Cured lumps on sheet surface	Tread: pick out lumps, blend at ≤1:4. Other compounds: thin-pass, then load ≤10 kg per batch in same-type final mix. If unusable → scrap.
Wood chips, cord pieces in sheet	Thin-pass; load ≤10 kg per batch in same-type final mix.
Tacky/stack-stuck sheets	Clean surface, separate stuck sheets, ensure dry before use.

2.4 Return Compounds and Semi-Finished Goods

• Cured lumps or debris in return compound: Isolate, thin-pass, load ≤10 kg per batch in same-type compound. If unusable → scrap.
• Dimensional/weight rejects: Follow return compound blending work instruction and specific formulation.
• Head compound (extruder startup): Follow return compound blending standard. If cured lumps/debris present: thin-pass then load ≤10 kg.
• Expired return compound: Blend at ≤1:1 ratio.

Key Principles Summary

1. Isolate and label first: Every non-conforming item must be clearly identified and quarantined before any disposition.
2. Blending ratios are capped: Downgraded compounds are blended at controlled ratios (typically 1:1 to 1:4) with normal material — never used alone.
3. Supplier accountability: Quality failures from incoming materials result in return, exchange, or supplier-paid scrap. Repeat failures trigger suspension.
4. Safety-critical materials are never compromised: Steel cord breaking strength, metal contamination in NR, and bladder defects that could cause tire failure are always rejected, not blended.
5. Documentation: Every disposition is recorded — tracking forms for raw materials, disposition forms for compounds — enabling traceability and supplier claims.