Non-Conforming Product Handling in Tire Manufacturing: Complete SOP

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

1.2 Reinforcement Materials (Cord, Wire, Fabric)

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

2.2 Masterbatch Compounds

2.3 Final Mix Compounds

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.