In the textile industry, two issues that affect the appearance of textile products are snagging and linting. To ensure the maximum performance of the textile material, a testing method known as ASTM D3939 is used to assess its resistance to snag. A Mace Snag tester is used to perform this test. This article will guide you to explore ASTM D3939.
What is Snagging
Snagging refers to the pulling out of the yarn loop from the upper surface of the textile material. This testing method is used for all textile materials made by the weaving or knitting process. To ensure optimal performance of textile materials, ASTM D3939 is used to assess their tendency to snag.
ASTM D3939 Test Method Procedure
Preparation of the Testing Specimen
- Laundering
Load the washer with around 3.5 kg. If your sample is lower than the required weight, please use a dummy load and make the total wash load 3.5 kg. Add AATCC standard reference detergent 124, set normal wash, and the water temperature should be selected as warm, and run the machine.
- Drying
Select the drying parameter as normal cycle, medium temperature and run the drying machine for 20 minute till the hand feel of the textile material as dried.
- Cut the testing specimen from the dry sample and fold each specimen from the front side, and form a sleeve shape by sewing. The stitching parameter should be 10 stitches per inch ( SPI 10 stitches/In).
- Turn each specimen inside out so the surface of the testing specimen will be exposed.
Preparation of Testing Apparatus
- Place the testing specimen centrally on the testing machine’s drum.
- With the help of hot water, wet the testing specimen and then let it completely dry. (You can speed up the drying process with the help of temperature or a heat source.
- Replace the testing specimen if there is any damage.
- Keep the distance of 45mm or 1.8” between the mace from the drag bar.
- Check all the balls, and all balls should be freely movable.
- 600 total revolutions are required, and the timing will be approximately 10 minutes.
- The drum speed should be 60 ± 2 round per meter.
Calibration of Testing Apparatus
- Use the standard calibration fabric on known snagging and resistance rating, and check the operation of the testing apparatus.
- If after test results are the same as per the standard calibration fabric.
- ±0.5 rating difference is acceptable
- To evaluate testing results, use DaRong pilling and snagging tester rating box model YG (B)901
Conditioning
- Keep all the testing specimens in the standard atmosphere required for textile testing.
- The temperature of the conditioning area should be 21 ± 1 °C
- The relative humidity of the conditioning area should be 65 ± 2 % as mentioned in AATCC 1776.
- The conditioning time should be 12 hours before testing.\
- To get standard atmosphere conditions, use the Darong temperature and humidity chamber, which provides accurate atmospheric conditions that help in the repeatability of the precise results.
Testing procedure
- Perform all testing in a conditioned area where the temperature should be 21 ± 1 °C and the relative humidity should be 65 ± 2 %.
- If there is any visual snag before testing on the testing specimen, replace the testing specimen and use a new one.
- Place the testing specimen on the felt-covered drum and the testing surface of the testing specimen should be outward with the seam.
- Tighten the testing specimen with the help of masking tape. Tighten the area of the testing specimen about 1” or 25mm edges with masking tape.
- Keep the position of the mac; there is no restriction over the entire drum surface.
- Adjust 600 revolutions on the counter of the tester and operate the mace snagging tester.
- After completion of the testing method, remove the testing specimens from the drums.
- From the center seam, fold the testing specimen.
- Keep the seam facing down for rating.
Evaluation
- Rate your testing specimen with the help of the ICI photographic snagging standard or by the help of a rating scale that varies from 1 to 5 (1 is for several snags, meaning this is the unacceptable quality of the textile material, and 5 is for no visible snags) or rate by a trained visual observer. Used Darong pilling and snagging tester rating box YG(B)901, which provides a perfect viewing angle as per the international standard and gives the option of different light sources as per customer requirements.
Report preparation
Your report must contain below points.
- Testing specimen preparation
- The distance between the seam line and the short edge of the testing specimen.
- Number of revolutions
- Rating standard and light source of the viewing cabinet
- Report all requirements mentioned in the departmental report format.
FAQs
What is ASTM D3939?
ASTM D3939 is a testing method that was developed by ASTM International to assess how much a textile material resists to snagging in a controlled atmosphere using a tester called the Mace Snag Tester.
What type of fabric can be tested using ASTM D3939?
ASTM D3939 is suitable for both woven and knitted fabrics.
What is the snag resistance rating scale?
Textile materials are visually rated on a scale from 1 to 5 as below:
- 5- No visible snags
- 4- Slight snags
- 3- Moderate snag
- 2- Severe snags
- 1- Extremely severe snags
How many specimens are needed for the test?
Usually, six testing specimens are required for this test.
How many revolutions are performed in the test?
600 revolutions are the standard test duration, but can vary as per customer requirements.
- What are the factors that affect snagging resistance?
- Fiber type, such as filament or spun
- Fabric construction
- Yarn structure
- Fabric finishing
- Testing conditions