A woven interlining that has already been tested may need to be tested again when the production conditions change. Dimensional behaviour depends on the material, outer fabric, garment construction and processing conditions, so a change in any of these areas can alter the result.
One reason for retesting is a change in the production process. Different levels of heat, moisture or pressure can expose the interlining to different conditions. Changes to pressing, steaming, washing or other finishing methods can also affect the material. The same consideration applies when a new outer fabric is introduced.
Material changes can also justify a new test. A new interlining batch, supplier or material specification represents a new combination to evaluate. Even when a previous test produced an acceptable result, it should not automatically be transferred to a different grade or production setup.
The testing process can remain straightforward. Take a representative sample, record its original measurements and expose it to the process that will actually be used. Allow it to settle fully and measure it again using the same reference points. Calculate the dimensional change and compare it with the garment’s requirements. The fused pair should also be checked for flatness and signs of rippling, puckering or distortion. Retesting before bulk production allows manufacturers to identify whether the changed conditions require approval, adjustment or a different material. The objective is not to test unnecessarily, but to check whenever a meaningful change creates a new dimensional-stability question.
