Stretch Film Thickness Test – ASTM, ISO Standards Compliance

Ensure precise measurement of wrap film and stretch film thickness with our advanced testing methods. Compliant with ISO 4593, ASTM D6988, and ASTM F2251, our thickness testing solutions guarantee reliability for packaging quality control, R&D, and production standards.

Thickness Gauge anvil and presser foot

Why Wrap Film Needs Thickness Testing and Its Importance

Thickness is one of the most critical properties of stretch films, whether used for wrapping pallets, packaging industrial goods, or other applications. Proper thickness ensures the material’s tensile strength, stretch capacity, and tear resistance, directly affecting the product’s protective qualities and its ability to hold loads securely.

The thickness of the stretch wrap also determines the film’s strength and load-holding capacity. Thicker films generally provide better performance in terms of puncture resistance and overall load stability during transportation and storage. 

Online Thickness Measurement vs. Laboratory Thickness Measurement

When it comes to measuring film thickness, two primary methods are used: online thickness measurement (in-line) and laboratory testing.

Online Measurement: In-line methods offer continuous, real-time measurement during production, typically using sensors, laser technology, or non-contact methods like XRF (X-Ray Fluorescence) or UV-Vis spectroscopy. These methods can monitor thickness dynamically but may lack precision in some cases and can be affected by environmental factors (e.g., temperature, film stretch).

Laboratory Testing: Laboratory-based thickness measurement, such as the contact method using calipers or micrometers,or our FTT-01 Thickness Tester provides more accurate and reliable results. With the contact method, such as the use of precision thickness testers (like ASTM D6988), a sample is measured at specific locations, ensuring uniformity and consistent quality assurance. These tests are better suited for certification, R&D, and quality control due to their repeatability and precision.

Non-contact vs. Contact Thickness Measurement Methods

While non-contact methods such as XRF, X-Ray, and UV-Vis are highly useful for continuous monitoring of films during production, contact methods provide a higher level of precision when it comes to measuring the exact thickness of stretch films.

Non-contact methods are valuable for fast-paced environments but may be influenced by material inconsistencies or variations, whereas contact methods guarantee more accurate and reproducible results, making them preferred for laboratory testing and quality control.

Industry Standards for Thickness Testing 

ASTM D6988

ASTM D6988 is the standard test method for measuring the thickness of plastic films and sheets. This method involves the use of a micrometer or other suitable contact device to measure thickness at specified locations of a sample, ensuring high precision in determining the uniformity of the film thickness.

ASTM F2251

ASTM F2251 outlines the method for measuring the thickness of stretch films specifically used in packaging applications. This test method is critical in determining whether the film meets specified thickness requirements to ensure optimal performance during application and storage.

ISO 4593

ISO 4593 provides an international standard for the determination of thickness using various testing methods, including the use of micrometers and gauges. This method is designed for a range of plastic films, including stretch films and wrap films, and ensures consistency across global quality assurance practices.

Ensure Compliance with Industry Standards Using Our FTT-01 Thickness Tester

FTT-01 Thickness Tester is designed to meet the highest industry standards, including ASTM D6988, ISO 4593, and ASTM F2251. With its precise contact measurement capabilities, the FTT-01 provides highly accurate and reliable results for determining the thickness of stretch and wrap films. Whether you need to ensure compliance with packaging specifications or perform quality assurance testing, our tester guarantees consistency and precision in every measurement.

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Know More About FTT-01 Thickness Tester

Test Overview

The process for measuring the thickness of stretch and wrap films involves the use of precise testing methods, ensuring that the material meets required specifications for strength, uniformity, and performance. This overview covers the testing procedures according to ASTM D6988, ISO 4593, and ASTM F2251, the most commonly referenced standards for measuring the thickness of plastic films, including stretch and wrap films.

Step-by-Step Test Procedure

1.Sample Preparation

Test specimens are taken from several rolls of film, and where possible, from several production runs of film. Cut test specimens, about 100 mm wide, across the whole width of the sample, or a roll of film of similar width. The specimens shall contain no creases and no other defects.

Allow specimens to equilibrate at 23±2°C (73.4±3.6°F) and 50±0 % relative humidity.

2.Tester Preparation

Place the instrument FTT-01 Thickness Tester on a solid, level, clean table or bench that is free of excessive vibration. Confirm that the anvil and presser foot surfaces are clean. Allow it to reach a thermal equilibrium with the ambient. 

3.Start Measuring

Insert and position a specimen between the presser foot lifted from the anvil. The FTT-01 Thickness Tester will automatically lift, lower and measure the preset measuring point numbers. 

Thickness Gauge Presser Foot

4.Calculation

After the thickness of the specimens at points equally spaced along the length of the specimen is measured. The tester automatically displays the maximum, minimum and average thickness of the measured points.

Thickness Test Results

Stretch Wrap Gauge Thickness Conversion Chart

When measuring stretch wrap thickness, it is important to understand the various units used, including Gauge, Mil, Micron, Millimeter, and Inch. Below is a conversion chart to help you compare and convert these different units.

Gauge Mil  Micron (µm) Millimeter (mm) Inch (in)
23 Gauge 0.23 Mil 5.8 µm 0.0058 mm 0.0002 in
30 Gauge 0.30 Mil 7.6 µm 0.0076 mm 0.0003 in
40 Gauge 0.40 Mil 10 µm 0.0101 mm 0.0004 in
50 Gauge 0.50 Mil 12.5 µm 0.0127 mm 0.0005 in
60 Gauge 0.60 Mil 15 µm 0.0152 mm 0.0006 in
75 Gauge 0.75 Mil 19 µm 0.0190 mm 0.0007 in
80 Gauge 0.80 Mil 20 µm 0.0203 mm 0.0008 in
90 Gauge 0.90 Mil 23 µm 0.0228 mm 0.0009 in
100 Gauge 1.0 Mil 25 µm 0.0254 mm 0.0010 in
120 Gauge 1.2 Mil 30 µm 0.0304 mm 0.0012 in
150 Gauge 1.5 Mil 38 µm 0.0380 mm 0.0015 in

Conversion Guidelines:

  • Gauge to Mil: Gauge is essentially the thickness of the film in mils (thousandths of an inch), with 1 Gauge = 0.01 Mil.
  • Mil to Micron:
    • 1 Mil = 25.4 Microns (µm).
  • Micron to Millimeter:
    • 1 Millimeter (mm) = 1000 Microns (µm).
  • Millimeter to Inch:
    • 1 Inch = 25.4 Millimeters (mm).

FAQs about Wrap Film Thickness Test

What is the importance of measuring the thickness of stretch wrap films?

Measuring the thickness of stretch wrap films is crucial for ensuring the material’s performance in packaging applications. Consistent thickness affects the film’s stretchability, strength, and sealing properties. Variations in thickness can lead to inadequate pallet stability, improper sealing, or film breakage during handling, which can ultimately impact product safety and logistics efficiency. International standards, such as ASTM D6988, ASTM F2251 and ISO 4593, provide guidelines for achieving consistent thickness and material integrity, ensuring that stretch films meet specific performance requirements.

What methods are used to measure film thickness?

Two common methods are used for measuring the thickness of stretch films: contact methods (micrometers or mechanical gauges) and non-contact methods (e.g., X-ray, ultraviolet-visible (UV-Vis) spectroscopy, and laser). The contact method, as used by the FTT-01 Thickness Tester, is widely regarded as the most accurate and reliable for standard thickness testing, offering consistent measurements with high precision. While non-contact methods can be beneficial for high-speed applications, they may not offer the same level of detail and repeatability as contact-based approaches.

 

How does the gauge of a stretch film relate to its thickness, and why is this important?

The gauge of a stretch film refers to its thickness, typically measured in microns or mil (thousandths of an inch). The higher the gauge number, the thicker the film. For example, an 80-gauge stretch wrap film is thicker than a 60-gauge film. Thicker films tend to offer more strength and durability, which is essential for heavy-duty applications like pallet wrapping, providing better protection and stretch. Manufacturers use the gauge measurement to ensure the film’s thickness meets industry standards for specific packaging requirements, such as ASTM F2251 for stretch film packaging.

What are the most common issues with film thickness variations, and how can they be mitigated?

Common issues with film thickness variations include inconsistent material distribution, manufacturing defects, and variations in the stretching process. These discrepancies can cause weak spots in the film, leading to poor load containment, film breakage, or improper sealing. To mitigate these issues, it is essential to conduct regular thickness testing using tools like the FTT-01 Thickness Tester. Ensuring that the film meets the required thickness specifications and conducting quality control checks throughout the production process helps to reduce variations, ensuring uniformity and reliability.

How does the thickness of stretch films impact their performance during pallet wrapping?

The thickness of stretch films plays a significant role in their ability to hold loads securely during transit and storage. Films that are too thin may stretch too easily, resulting in insufficient cling and load containment. On the other hand, excessively thick films can be challenging to stretch and may result in excessive waste or higher material costs. By measuring thickness, manufacturers can determine the optimal thickness for various applications, ensuring that films provide the right balance of strength, stretchability, and cost-efficiency for effective pallet wrapping.

Which units are used for Stretch Wrap Thickness

The units commonly used for Stretch Wrap Thickness are:

  1. Gauge (gauge number)
  2. Mil (thousandths of an inch)
  3. Micron (µm)
  4. Millimeter (mm)
  5. Inch (in)

For stretch wrap thickness, Gauge and Mil are widely used in the U.S., while Micron and Millimeter are preferred internationally and in scientific contexts for more precision.

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