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Tensile testing of glass fiber PCB substrate

As a commonly used circuit board material, glass fiber PCB substrates play an important role in electronic device manufacturing and application fields. It uses epoxy resin as binder and glass fiber cloth as reinforcing material, which has high temperature working capacity and small environmental impact. Especially in double-sided PCBs, glass fiber PCB substrates are widely used. Although it is more expensive than composite PCB substrates, its superior performance makes it the first choice for many electronics manufacturers.

PCB circuit board is a necessary electronic component of equipment and electrical appliances, but also a necessary carrier for software implementation, different devices have different PCB materials. For rigid printed circuit boards (RPCB), it is generally divided into many kinds according to PCB board reinforcement materials: phenolic PCB paper substrate, composite PCB substrate, glass fiber PCB substrate and other substrates such as metal substrates and multilayer boards.

This article will explore the tensile properties of glass fiber PCB substrates and evaluate their mechanical properties by performing tensile tests. We will refer to relevant standards and methods, use ethyl strong glue to make end shanks, and perform tensile tests with the help of universal testing machines to measure key parameters such as tensile strength and elastic modulus of glass fiber PCB substrates.

Table of Contents
Glass fibre tensile test maxresdefault

Test criteria

Glass fiber reinforced plastics are widely used in electrical insulation fields, construction fields, biomedical fields and other aspects of life. Among them, most of the current PCB substrates will use glass fiber laminated reinforced plastic. This experiment will refer to “GB/T 1040-2018 Determination of tensile properties of plastics” to test the tensile properties of fiberglass board.

Test instruments

Test instruments-universal testing machine
Test instruments-universal testing machine

1. Universal testing machine

2. Wedge fixture

3. Extensometer

4. Experimental conditions

Sample name: glass fiber plate

Number of samples: 1 group

Test temperature: room temperature

Test type: plastic tensile test

Test speed: 0.5 mm/min (extensometer strain stage) sensor capacity: 100 kN

The test process

The tensile test process of glass fibre PCB
The tensile test process of glass fibre PCB

1. Preparation materials: prepare glass fiber PCB substrate samples and required test equipment, including universal testing machine, 100 KN pneumatic wedge clamp, displacement measurement device (gauge extensometer) and ethyl strong glue.

2. Sample preparation: prepare the test sample and paste it with ethyl strong glue at the end to make the end handle. Make sure the adhesive is secure and the end shank is tightly connected to the sample.

3. Clamping sample: Place the prepared sample in a 100 KN pneumatic wedge fixture to ensure that the clamping is firm and the connection point between the clamp and the sample end handle is in a suitable position to avoid the sample breaking at the clamp due to brittle fracture.

4. Set test parameters: set the test parameters of the universal testing machine, including the test speed and loading range. In this test, a test speed of 0.5 mm/min was selected for the tensile test to ensure stable and accurate data acquisition.

5. Start test: start the universal testing machine and start the tensile test. The testing machine will gradually apply tensile force at a set speed until the sample breaks. At the same time, the displacement measuring device will record the change in the displacement of the sample during the stretching process.

6. Data recording and analysis: During the test, timely record the tensile strength, elastic modulus and other relevant data of the sample. Once the sample has broken, stop the test and record the break location and morphology. According to the test data, the corresponding data analysis and result evaluation are carried out.

7. End of test: After completing the test, clean up the test site and properly save the test data and samples.


The electronic universal testing machine combined with the extensometer performs a tensile test on the glass fiber PCB substrate to test its elastic modulus, tensile strength and other mechanical properties. The test results show that the universal testing machine is able to meet the test needs of this type of sample, and the use of a 100 kN pneumatic wedge grip ensures a stable grip of the sample, thus obtaining stable and reliable data.

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