Cohérence d'un lot à l'autre : que demander avant de répéter une commande

Most buyers check the first shipment carefully and the tenth not at all. Drift between batches is where quality problems usually appear.

Build a retained reference

Keep a sealed sample of the approved batch under the storage conditions the supplier specifies. When a new batch arrives, test it against the retained sample on the same instruments on the same day. Comparing two batches tested months apart on different machines tells you very little.

The four questions to ask

• •What is your specification range for the critical property? A supplier quoting an unusually wide band is telling you their control is loose.
• •Do you test every batch or on a sampling plan? Ask what happens when a sampled batch fails.
• •Can you provide the COA for the specific batch I am buying, before shipment?
• •What is your change-control process? If a raw material source changes, do customers get notified?

Practical incoming checks

For rubber chemicals: appearance, melting point or assay for the active ingredient, heating loss, and sieve residue where dispersion matters. For compounds: Mooney viscosity, rheometer t90 and hardness on a standard test sheet. Log every result — a drifting trend over six shipments is far more useful than any single pass/fail.

Set the acceptance band in the contract before the first shipment, not after a dispute. ## Need the documents or today's price? Send us the grade, quantity and destination port — we return a quotation with COA and MSDS attached. Email manager@fipolymer.com or use the inquiry form on this site.