Definition
A paper tensile strength tester is a specialized device used to measure the resistance of paper and its related materials to breakage during stretching. The instrument evaluates the mechanical properties of materials by applying axial tension to the fracture of the specimen, recording its maximum load and elongation changes. Its test results are usually expressed in parameters such as tensile strength, elongation at break, and tensile energy absorption, and are widely used in papermaking, packaging, printing, and materials research.
How it works:
The instrument is based on the principle of static tensile testing, where a standard-sized specimen is clamped between the upper and lower clamps. The upper gripper is controlled by the drive system to move at a uniform speed and apply a gradually increasing tensile force to the specimen. The lower clamp is connected to the force value sensor to monitor the force change in real time. When the specimen breaks, the system automatically records the maximum force value and the corresponding elongation. According to the formula of material mechanics, the tensile strength can be expressed as:
σ = F / (w × t)
Among them σ is the tensile strength (unit kN/m or MPa), F is the maximum fracture force value (unit N), w is the width of the specimen (in mm), and t is the thickness of the specimen (in mm). The elongation is calculated by measuring the ratio of the fixture displacement to the original gauge distance by the displacement sensor.
Measurement method
Testing is subject to standardized operating procedures. First, prepare specimens of specified sizes according to relevant standards (such as ISO 1924, GB/T 12914, etc.), usually in the form of long strips. The specimen is clamped flat in the fixture to ensure that the stress axis coincides with the center line of the specimen. Set the test parameters including tensile speed, initial clamping distance, etc., and start the test program. The instrument automates the stretching, data acquisition, and result calculation process. Each group of specimens needs to be repeated multiple times, and the statistical valid value is taken as the final result. The test environment usually requires temperature and humidity control to reduce the impact of environmental factors on paper performance.
Influencing factors
The accuracy of test results is influenced by multiple factors. The material includes internal structural characteristics such as fiber type, pulping degree, filler content, moisture balance and paper uniformity. Instrument factors include whether the fixture design is anti-slip, whether the clamping force is uniform, the accuracy of the force sensor and the calibration status. Operating conditions such as tensile speed, specimen clamping alignment, temperature and humidity environment control, etc. also directly affect data reliability. In addition, edge burrs, dimensional deviations, or mechanical damage during specimen preparation can cause measurement deviations.
Applications:
The instrument has important application value in several industrial fields. The paper industry is used to monitor the mechanical properties of finished paper, cardboard, and specialty paper, and to guide production process adjustments. The packaging industry evaluates the weight capacity and durability of packaging materials such as corrugated boxes and paper bags. The printing industry tests the tensile properties of printing paper during high-speed printing. scientific research institutions and quality inspection departments use it for new material development, product compliance verification and quality arbitration testing. Relevant data can also provide a basis for product standard formulation and transportation plan design.
Selection reference
When selecting instruments, it is necessary to comprehensively consider the technical parameters and usage needs. The range should cover the maximum force value of the material to be measured, usually equipped with multi-level force value sensors to accommodate different weight weight papers. The accuracy level needs to meet the corresponding standard requirements, and the force resolution is generally recommended to reach 0.5% of the full scale. The fixture type should match the specimen characteristics, such as flat clamps for ordinary paper, corrugated clamps for corrugated cardboard. The control system should have functions such as adjustable speed, automatic reset, and data statistics. In terms of expansion capabilities, additional analysis modules such as elastic modulus and stress-strain curves can be considered. In addition, the instrument's ease of calibration, software compatibility, and maintenance costs should also be considered.