Woven interlining does not work independently in a finished garment. It is bonded to an outer fabric, so dimensional stability needs to be considered in relation to both materials. If the interlining and outer fabric change size by different amounts, the bonded area may develop rippling, puckering or distortion.
The characteristics of the outer fabric can affect this result. Fibre, weave and stretch are relevant factors because they influence how the outer material responds to production conditions. Garment construction also matters because the position and size of the fused area can affect how dimensional changes appear.
For this reason, testing woven fusible interlining with the actual outer fabric can provide a more useful result than relying on the interlining alone. A new outer fabric should be treated as a new combination even if the interlining has previously been tested. The same applies when garment construction changes or when the production process is modified.
A representative sample can be used for the test. Record the initial dimensions, expose the interlining and outer fabric to the relevant production process, allow the sample to settle and measure it again. The dimensional change can then be calculated and compared with the production requirements. The fused pair should also be checked for visible problems such as rippling or puckering. Testing the combination helps manufacturers understand whether the interlining and outer fabric remain stable together under the conditions they will experience. A result from one outer fabric should not automatically be applied to another because each material combination can behave differently.
