This article is provided by Jinan Saicheng Electronic Technology Co., Ltd

The stretch performance tester for stretch wrap film is a key equipment used to evaluate the mechanical properties of wrap film during the stretching process. It mainly simulates the stretching behavior in practical applications, measures parameters such as tensile strength, elongation at break, elastic modulus, etc., to reflect the material's tensile ability, ductility, and rigidity, and provides data support for product optimization and quality control.

1、 Testing principle and core parameters

Test Principle

During testing, the wrapped film sample is stretched at a constant speed until it fractures. The equipment records force and displacement data in real time, generates a stress-strain curve, and calculates the following parameters:

Tensile strength: The stress that a film can withstand before fracture, reflecting its tensile strength.

Elongation at break: The percentage of elongation at which a film breaks, reflecting its ductility (pre stretched film must be ≥ 400%).

Elastic modulus: The slope of the linear segment of the stress-strain curve, which characterizes the rigidity of a material.

Key performance indicators

Accuracy: The measurement accuracy, velocity accuracy, deformation accuracy, and displacement accuracy can reach ± 0.5%, and generally manufacturers can meet the requirements with ± 1%.

Force resolution: It can basically reach one hundred thousandth, ensuring data accuracy.

Measurement speed: Depending on the material properties, the film testing speed range is usually 50-500mm/min.

2、 Testing process and operating standards

Sample preparation

Cutting: Cut the sample according to the standards (such as ASTM D882, ISO 1184, BB/T 0024-2018), usually a rectangular sample with a length of 150-200mm and a width of 15-25.4mm.

Protection: The edges of the sample should be smooth and free of gaps, and can be inspected with a low-power magnifying glass; Protect the inner and outer surfaces of the sample with separating paper to prevent contamination from hand contact.

Measurement: Use a caliper or thickness gauge to measure the width and thickness of the sample, and record the data.

Device Settings

Fixture selection: Choose a flat or corrugated clamp based on the characteristics of the sample to ensure clamping without damaging the sample.

Parameter setting: Set the stretching speed (such as 125mm/min ± 12.5mm/min), initial gauge length (such as 100mm), and test mode (stretching or elongation at break test).

Environmental control: The testing environment temperature is 23 ℃± 1 ℃, the relative humidity is 50% ± 5%, and the sample pretreatment time is ≥ 4 hours.

Test Execution

Fixed specimen: Fix both ends of the specimen in the upper and lower fixtures, ensuring alignment and no initial stress.

Start test: The device automatically applies tension, records force and displacement data until the sample fractures or reaches the preset elongation.

Data collection: After the test is completed, the equipment automatically saves the data and calculates indicators such as elongation at break and tensile strength.

Result Analysis

Repeat testing: Test each sample at least 3 times and take the average as the final result.

Report generation: Organize data to generate tables or charts, including indicators such as tensile strength and elongation at break, and save or print the report.