The Right Way to Do Random Sampling During Production in China

Material substitution is a common issue in China manufacturing. The factory may use a different grade of steel, a different type of plastic, or a different fabric than specified — usually without telling you. This often happens when the specified material is out of stock or more expensive. Protect yourself by: specifying brands or grades, requesting material certificates, conducting random material testing, and including a clause in your contract that unauthorized material changes void the quality guarantee.

The 5-point quality control system is the industry standard for China manufacturing. Point 1: Raw Material QC — verify incoming materials against specifications before production. Point 2: In-Process QC — inspect during production, not just at the end. Point 3: Pre-Shipment QC — random sampling before container loading. Point 4: Loading Supervision — confirm quantity, packaging, and marks. Point 5: Corrective Action — when defects are found, ensure the factory implements permanent fixes, not quick patches.