One of the fundamental physical characteristics of textile materials is thickness. Thickness values are frequently used to evaluate the bulk and thermal qualities of textile materials. In this article, the fabric thickness test is described in detail, along with its importance, usage, and test methods, ASTM D1777, used in cloth testing laboratories.
This test helps determine how fabric will behave in real-life conditions, including insulation, flexibility, air permeability, and comfort. To ensure materials meet international quality standards such as ASTM, ISO, and GB/T, many textile manufacturers and exporters rely on thickness measurements. With the help of these test results, textile engineers and designers can predict how a material will perform when used in the preparation of upholstery, industrial textiles, and garments.
Fabric Thickness
The fabric structure is composed of small fibers. These fibers contain air spaces in between them. These air spaces are fragile, and even slight pressure would empty them. Fabric thickness is affected by the pressure applied during measurements. The applied pressure and fabric thickness are inversely proportional. So, when mentioning fabric thickness, you must also specify the pressure used to measure it.
There are some air gaps in the fabric, and if we apply more pressure during measurement, it will appear thinner because these tiny air gaps will collapse. This is the reason why consistent testing pressure is essential for accurate results. This standard pressure allows lab to compare their results across different samples and testing facilities. Usually, thicker fabric traps more air, providing better insulation and warmth. For example, woolen fabric feels warmer than lightweight cotton fabric.
Fabric thickness plays a pivotal role in determining performance characteristics and warmth properties. Abrasion and shrinkage processes may involve fabric thickness before and after the test. Fabric thickness is also critical in some industrial processes, where it needs to be within specified limits.
Thickness directly influences how the fabric behaves in real-world use. Technical textiles and automotive applications require controlled, precise thickness for insulation and strength, whereas in fashionwear and apparel, thickness affects drape and comfort. The relationship between GSM and thickness allows for a balance of softness, warmth, and durability.
What is ASTM D1777
In the physical testing of the fabric, a sample is placed between a weighted presser foot and a thickness gauge. The weighted presser foot is lowered slowly. The thickness of the specimen is determined by measuring the distance between the base plate and the presser foot.
To measure textile thickness under controlled conditions, such as temperature and humidity, ASTM International developed the testing standard ASTM D1777. A digital thickness gauge such as Thickness Tester YG(B)141G is used for this test. The accuracy of the test depends entirely on the instrument’s calibration and the environmental conditions of the test specimen.
Similar Test Methods to ASTM D1777
In addition to ASTM D1777, other regions of the world also use other standards to measure the thickness of fabric and nonwoven materials. Some of them are listed below.
- GB/T3820 – Determination of thickness of textiles and textile products
- GB/T24218.2 – This method deals with test methods for nonwovens. Part 2: Determination of thickness
- ISO 5084-1996 – Determination of thickness of textiles and textile products
Each standard has its own method and should be understood before following.
Test Conditions – Temperature and Relative Humidity
Samples should be conditioned before testing at 21 ± 1°C having Relative Humidity 65 ± 2 for 4 hrs. Same conditions should be carried out throughout the test.
Textile materials made from natural fibers, such as cotton and viscose, are susceptible to environmental conditions, including temperature and humidity. When exposed to moisture, fibers can swell, which directly affects thickness and other essential properties, such as weight and strength. Maintaining standard atmospheric conditions will help ensure comparable results across different batches and labs.
Apparatus for ASTM D1777
- Thickness Gauge or Fabric Thickness Tester. (2 models of ASTM D1777 thickness tester from Darong are shown in pictures).
- Cutting Dies or Templates for Fabric Cutting. These are used to cut samples. The sample should be 20% larger than the presser foot of the tester.
These testers typically include a base plate, a pressure foot, a digital display, and a loading weight. Modern testers are equipped with automatic loading mechanisms and a digital display that shows results. Sample cutting is also very important. Uneven testing specimens can distort readings. Always ensure that the fabric is laid flat and wrinkles-free.
ASTM D1777 Testing Procedure
- Turn on the power switch for the fabric thickness tester.
- According to the standard, select the test parameters.
- Pressuring time can be either 10 sec or 30 sec, or you can choose between single or multiple tests.
- For a standard test, it is recommended to use a pressure foot area of 2000mm2 and an applied pressure of 1000Pa, requiring the placement of 200 weight.
- After setting up, press the start button.
- In the absence of a sample, zero the thickness display.
- Place the sample with the test surface facing up on the instrument, ensuring the surface is flat and wrinkle-free.
- Press the start button to begin the test.
- After 10 sec of pressurization, the reading light will be on, and the instrument will emit a prompt sound.
- Read the thickness value at that moment.
- After completing one, test the remaining sample using the same method.
- Once all tests are completed, calculate the test results according to the standard.
During performing this test, consistency is key. A slight change in fabric placement or a delay while measurements are being taken influences results. I will recommend taking multiple readings across different samples and providing the mean reading as the result. It will minimize the chances of errors and represent the fabric true thickness. Using calibrated instruments and a well-trained technician ensures repeatability and accuracy.
Report Formation
To make a fabric lab test report, ensure the following points.
- Enter details about the sample’s material. (e.g., yarn and fiber count and material, Type of Weave and knits, type of chemical treatment if applied, etc.)
- Briefly describe the sampling method.
- Mention the applied pressure on the fabric while testing.
- Mention the date of the test performance.
- Report that the thickness test is performed in accordance with ASTM D1777.
For quality control, certification and customer assurance a well prepared lab report is very important having details like type of the fiber, structure of the yarn and weave pattern. Many labs usually include graphs and digital screenshots from the tester as evidence in the report.
Conclusion
Fabric thickness is an essential property of textiles. It directly affects other important fabric properties like thermal insulation, fabric compactness, air permeability, dimensional stability, and abrasion. It also helps in understanding fabric geometry. So, fabric thickness should be considered if you require the above fabric properties.
Whether you are a textile manufacturer, quality control specialist, or researcher, understanding ASTM D1777 will help you evaluate material performance and maintain consistency. Thickness is a vital parameter for developing high-quality fabric for textile articles, including apparel, upholstery, and technical applications.
Experience and Insights
- Don’t stretch fabrics for straightening, as it directly affects their thickness. Always use pre-conditioned fabrics for testing.
- Most materials are generally tested with a circular presser foot. However, some materials can be tested by using rectangular feet.
- When discussing or listing any thickness value, the applied pressure must be mentioned.、
FAQs
What is ASTM D1777 96?
In textile testing standards, this is an international method used for measuring the thickness of textile materials. It can also be used in leather products and in the packaging industry.
What is the fabric thickness measurement unit?
Usually, it is measured in millimeters (mm). Fabric thickness in mm eliminates the error percentage. Different fabric thickness testers have different limitations for measuring the minimum and maximum fabric thickness.
What Is GSM?
GSM stands for Gram per Square Meter. It describes the material’s weight. For example, a garment with the label “300 GSM” indicates that 300 grams of knit cotton were used per square meter of fabric.
Generally, GSM is directly related to fabric thickness. Coarser, bulkier fabrics have a higher GSM than lightweight fabrics. It is an essential property in garment R&D, where an appropriate fabric is selected based on the end use.
Which GSM fabric is good?
It depends on the fabric’s end use. Delicate fabrics can have as low GSM as 25, while heavy fabrics can weigh up to 450+ GSM. For a general idea, delicate fabrics like chiffon have less than 80 GSM, while denim can weigh up to 350 GSM.
Does higher GSM mean better quality?
Fabric GSM is not a quality parameter; it indicates the fabric’s weight. Usually, increased GSM values correlate with density, fabric thickness, and fabric structure compactness, which ultimately leads to fabric quality.
Which GSM Fabric is suitable for summer and winter?
In summer, people like to wear low GSM fabric (GSM < 150) for better feeling and breathability, while, in winter, people need heavy GSM fabric (200-350) to protect from winter.
Related Resource
ASTM D1777 Fabric Thickness Gauge YG(B)141D