Testing fabric for shrinkage is a method of evaluating the dimensional change of a fabric material under conditions such as washing or dry cleaning. The following are common methods of testing fabric shrinkage:
1. Sample preparation:
- Select suitable fabric samples and label them for subsequent comparative analysis.
- Determine the initial size of the sample using standard sizing specifications. Industry standards or customized specifications can be used.
2. Washing:
- Place fabric samples in the washing machine or perform hand washing, following the desired washing conditions. Depending on the specific requirements of the fabric, different washing temperatures, detergents and washing times can be selected.
- Pay attention to the consistency of the washing conditions during the test and try to avoid other external factors from interfering with the test results.
3. Drying:
- Air dry the washed fabric samples or use a dryer for drying. Make sure that the temperature and time of the drying process match the selected washing method and conditions.
4. Measurement:
- Measure the dimensions of the washed fabric samples using appropriate measuring tools (e.g. measuring tape, pattern projector, scanner, etc.).
- Take dimensional measurements in various directions (horizontal, vertical, etc.) and on multiple parts of the sample to obtain more accurate and comprehensive results.
5. Data analysis:
- Compare the dimensional data of the washed fabric samples with the initial dimensions.
- Calculate the shrinkage of the fabric, usually expressed as a percentage. The formula is: Shrinkage = (Initial size - After washing size) / Initial size × 100%.
It should be noted that in order to obtain accurate and reproducible test results, it is recommended to perform several repetitions of the test and to operate according to the test requirements and standards. In addition, different types and nature of fabrics may exhibit different shrinkage rates during the washing process, so the test should be conducted accordingly to the requirements of the particular fabric.
Meanwhile, you may also refer to international standards and test methods, such as ISO 5077 and ASTM D3774, which provide more detailed test procedures and calculation formulas for your reference and use.
Last but not least, if you are not familiar with the test methods or need more professional testing services, it is recommended to consult laboratories or professional testing organizations with relevant experience in order to obtain more accurate and reliable test results.