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How to measure the impact resistance of automotive window film?

Feb 25,2020

Source: Linktesting Instruments Co., Ltd

Window film is a thin film or laminate that can be installed to the interior of glass surfaces in automobiles, boats, homes and buildings. This article discusses automotive window film that can be applied on the windshield or sunroof of the automobiles. 

When the glass is broken it holds together, preventing dangerous shards from flying about, or to make it more difficult for an intruder to gain entry. That’s why the automotive window film is also known as anti-blast window film. The automotive window film can also reduce heat and glare and prevent the UV light. Moreover, by offering an unimpeded view from the low-light side but virtually no view from the high-light side, the automotive window film can protect the privacy of the users.

Generally, the automotive window film should have sufficient flexibility so that it can resist the impact from the external forces. If the impact resistance of the automotive window film is insufficient, when the automotive glass encounters external impact, the window film may not be able to protect the passengers from the dangerous shards and as a result the passengers may get wounded. Therefore, it is important for the manufacturers to inspect the impact resistance of the automotive window film to ensure its performance.

This article provides a simplified method for impact test of automotive window film. The specimens are provided by one brand automotive window film manufacturer. The testing instrument used in the tests is Linktesting’s LTJM-06 Pendulum Impact Tester.

Figure 2. LTJM-06 Pendulum Impact Tester

The tests can be performed according to the following procedures.

(1) Cut 10 pieces of specimens along the transverse direction of the sample. The size of the specimen should be 10cm by 10cm. Then condition the specimens at 23℃±2℃ and 45%RH ~ 55%RH for at least 4 hours. The tests should be performed also in the same environmental conditions.

(2) Measure the thickness of the specimen with thickness tester. Measure 10 points of each specimen and calculate the mean value of the 10 results.

(3) Select the impact head whose diameter is 12.7mm. Select specimen clamp diameter 89mm.

(4) Calibrate the instrument as required.

(5) Spread and clamp the specimen in the specimen clamp. Do not stretch the specimen and get rid of crinkles.

(6) Enter test interface. Fix the impact pendulum. Press Test button to release the pendulum. The pendulum will fall freely and impact the specimen. The impact energy will be displayed in the screen of the instrument.

(7) Test other specimens in the same way mentioned above and record the test results.

According to the test results, the manufacturer can determine whether the impact resistance of the automotive window film meets the requirement for practical use and may improve the manufacturing craft or change the raw materials to improve the quality of their products.

For more details about LTJM-06 Pendulum Impact Tester, please visit

About Linktesting Instruments Co., Ltd:

Linktesting Instruments Co., Ltd is one leading supplier of packaging testing instruments, which is headquartered in Jinan, China.

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