Meaning
A formal document defines the mandatory testing protocols and dimensional tolerances that a polymer raw material or moulded part must satisfy before it can be accepted for use. By establishing clear thresholds for parameters like density and melt flow rate, the quality assurance specification ensures consistency between production batches. This document outlines the testing methods and sampling frequencies required to verify compliance.
It defines the contract between the material supplier and the moulder.
Material Testing
Standardized test methods, such as those defined by ISO or ASTM, are listed in the document to evaluate the resin. These tests measure the physical and thermal behavior of the incoming polymer to guarantee it matches the required grade. Moulders run these tests to prevent out-of-specification material from entering the production line, which could cause process instability.
Production Tolerance
Allowable variations in part dimensions are defined to ensure correct assembly. These tolerances are determined based on the thermal shrinkage of the polymer. If a part falls outside these ranges, it is rejected.
Batch Verification
Every delivered lot of polymer resin is accompanied by a certificate of analysis that proves compliance with the document. This certification requires sampling a subset of each batch to confirm that the material meets the established criteria. Recording this data provides a traceable history of material quality, helping to diagnose any future processing issues and ensuring that any failure can be traced back to the specific raw material batch or production date.
