Application Guide for ASTM D1777 Fabric Thickness Test Standard

When a fabric is subjected to a specified pressure, the vertical distance between the front and back surfaces is called thickness, generally expressed in millimeters.

Fabric thickness is primarily related to yarn fineness, fabric weave, and the degree of yarn curvature within the fabric. Fabric thickness, generally expressed in millimeters, significantly impacts its wear properties. For example, a fabric's fastness, warmth, breathability, wind resistance, stiffness, and drape are all significantly affected by its thickness.

Factors Affecting Fabric Thickness Testing

Fabric thickness is typically measured using a fabric thickness gauge. Many factors influence fabric thickness, such as yarn linear density, fabric structure, yarn curvature within the fabric, and tension during production and processing. Furthermore, the selected presser foot area, applied pressure, and duration of application all influence the measured thickness.

a) Fabric thickness increases as the presser foot area increases.

b) Fabric thickness decreases as the applied pressure increases.

Thus, fabric thickness is a conditional value. Different presser foot areas, applied pressures, and reading times will yield different thickness values. Generally, the measured thickness of blankets and pile fabrics varies significantly, while that of coarse cloth and canvas fabrics varies less. Therefore, when measuring fabric thickness, the presser foot area should be selected according to standard recommendations, and the applied pressure should be determined based on the material's technical specifications or by mutual agreement. The selected presser foot area and applied pressure should be clearly stated on the test report.

During fabric production and processing, fabric thickness and density can be adjusted by controlling the yarn density and weaving method. Adjusting the yarn density can produce fabrics of varying thicknesses. Different weaving methods also affect fabric thickness and density.

Interpretation of ASTM D1777 Standard

During physical testing of fabrics, a sample is placed between a weighted presser foot and a thickness gauge. The weighted presser foot is slowly lowered. The sample thickness is determined by measuring the distance between the base plate and the presser foot.

Scope of Application

This standard primarily applies to textile materials with a thickness range of 0.01mm to 25mm, covering a wide range of types, from light gauze to heavy industrial fabrics. Its purpose is to ensure consistent, accurate, and comparable thickness measurements, helping manufacturers and testing agencies evaluate the physical properties of materials.

Basic Principle

This standard specifies the use of a precision thickness gauge to apply a specific pressure to the sample to eliminate air gaps and slack within the textile material, thereby determining the material's true thickness. The testing process includes the following key elements:

Contact Area: Depending on the material's properties, a contact surface with a diameter of 6.45 cm² (1 square inch) is typically used.

Applied Pressure: Depending on the material's softness, the pressure range is 0.98 kPa to 9.8 kPa to ensure no compression deformation.

Environmental Requirements: Testing must be conducted under standard ambient conditions of 23±2°C (23±2°C) and 50±5% relative humidity.

Test Methods Similar to ASTM D1777

In addition to the ASTM D1777 standard test method, other standards are used in different parts of the world to measure the thickness of fabrics and nonwoven materials. Some of these are listed below.

GB/T3820 – Textiles and textile products – Determination of thickness

GB/T24218.2 – This method covers test methods for nonwovens. Part 2: Determination of thickness

ISO 5084-1996 – Textiles and textile products – Determination of thickness

Each standard has its own method, which you should understand before following.

Test Conditions – Temperature and Relative Humidity

Prior to testing, the sample should be conditioned at 21 ± 1°C and 65 ± 2°C relative humidity for 4 hours. These same conditions should be maintained throughout the test.

Fabric Thickness Tester

As a high-precision, specialized testing device, the fabric thickness tester is designed to accurately measure the thickness of various materials, making it a vital tool for ensuring product quality and compliance with international standards.

Wide Range of Applications

The fabric thickness gauge has a wide range of applications, far exceeding its name. It's not only an essential instrument for textile mills to measure fabric thickness, but also serves as a quality control tool for a wide range of materials.

Carpet Industry: It accurately measures the overall thickness and pile height of carpets, and can professionally evaluate the compression set and elastic recovery of the backing under pressure, which are directly related to the carpet's feel, durability, and appearance.

Nonwovens and Geotextiles: In the industrial textile industry, the thickness of nonwovens and geotextiles directly affects their engineering properties, such as filtration, insulation, and drainage. This instrument provides a standard pressure, ensuring accurate and reliable measurement results.

Foam and Composite Materials: For bulky or multi-layered materials such as foam padding and composite fabrics, the instrument effectively measures their true thickness under a specified pressure, providing a basis for product design and cost control.

Leather and Rubber: It is also suitable for these slightly rigid materials that require high thickness uniformity, ensuring they meet the specifications of downstream manufacturers.

Outstanding Features and Benefits

The fabric thickness gauge's ease of use in a wide range of applications is due to its carefully designed features and advantages:

Excellent Compliance and Professionalism: The instrument is designed and manufactured in strict accordance with internationally recognized standards, including ISO, BS, and the New Zealand Wool Board. By equipping it with different pressure foot and weight combinations, it can easily generate standard pressures ranging from 2 kPa to 200 kPa, meeting the testing requirements of materials ranging from soft carpet to dense geotextiles, ensuring globally recognized and comparable test results.

High Flexibility and Expandability: The instrument's ingenious design allows for multiple uses by replacing various accessories. Dedicated pressure foot, reference plate, and weight kits are available for different test objects, including carpets, padding, and non-woven fabrics. The standard model can measure samples up to 25 mm, while other thickness ranges are available for thicker and specialized materials, providing a comprehensive and flexible solution.

Intelligent Operation and Data Processing: The device features an integrated digital display for clear and intuitive readings and an auto-zero function, simplifying operation and reducing human error. The standard RS232 interface and dedicated software enable easy connection to a computer for automated data collection, downloading, and analysis, significantly improving testing efficiency and ensuring scientific data management.

Sturdy and Reliable Design: The compact size (300mm wide × 400mm deep × 550mm high) and robust structure ensure high stability and measurement accuracy during long-term, repeated testing, providing reliable support for quality control in laboratories and production lines.

FAQ

What is ASTM D1777-96?

Among textile testing standards, this is an international method for measuring the thickness of textile materials. It is also used in the leather goods and packaging industries.

What is the unit of measurement for fabric thickness?

It is typically measured in millimeters (mm). Measuring fabric thickness in millimeters eliminates percentage errors. Different fabric thickness testers have different minimum and maximum measurement limits.

What is GSM?

GSM stands for grams per square meter. It describes the weight of a material. For example, a garment labeled "300 GSM" means 300 grams of knitted cotton were used per square meter of fabric surface area.

Generally speaking, GSM is directly related to fabric thickness. Coarser, fluffier fabrics have higher GSM values ​​than lighter fabrics. This is an important characteristic in garment development, as it helps determine the appropriate fabric for the intended use.

Which GSM fabric is best?

It depends on the fabric's intended use. Delicate fabrics can have a GSM as low as 25. while heavier fabrics can weigh as much as 450+ GSM. Generally, delicate fabrics like chiffon have a GSM below 80. while denim can weigh as much as 350 GSM.

Does a higher GSM mean better quality?

Fabric GSM is not a quality parameter, but rather a measure of fabric weight. Generally, increasing GSM values ​​correlate with density, fabric thickness, and the tightness of the fabric structure, ultimately determining fabric quality.

Which GSM fabrics are best for summer and winter?

In summer, people prefer to wear low GSM fabrics (GSM < 150) for better feel and breathability, while in winter, people need thick GSM fabrics (GSM 200-350) to withstand the winter.