Tensile testing machine, often referred to as material testing machine, is the core equipment for testing the mechanical properties of materials such as tension, compression, bending, and peeling. It widely serves the quality control and research and development processes of many industries such as packaging, textiles, adhesives, plastics, medical devices, etc. Understanding its precise structural composition is crucial for proper operation, maintenance of equipment, and even interpretation of test data. This article will systematically analyze the four core systems of modern electronic tensile testing machines: measurement system, drive system, control system, and data processing system.

The four core systems of the tensile testing machine

A high-performance electronic tensile testing machine is highly integrated with mechanical design, sensor technology, automatic control, and computer software technology. The essence of its work isApply controllable force or displacement to the specimen and synchronously measure these parameters with high precisionThe entire process is collaboratively completed by the following systems:

System deep analysis: how to achieve precise measurement and control

1. Measurement system: the "perception organ" of data
The accuracy of the measurement system directly determines the reliability of the test results.

• Force measurementThe core isStrain gauge force sensorWhen the sensor is subjected to force, the internal elastic element generates micro strain, and the resistance value of the strain gauge attached to it changes accordingly. By using a Wheatstone bridge circuit, the resistance change is converted into a micro voltage signal output, which can be amplified by an amplifier to accurately calculate the output value. Sensors are usually installed on beams or fixtures to directly sense the load on the sample.

• Deformation measurementFor precise measurement of parameters such as elastic modulus and yield point, it is necessary to useextensometerIt is directly clamped on the sample gauge and transmits the length changes of the sample to the sensor through mechanical or optical means, with an accuracy of up to micrometers. Before the specimen fractures, the extensometer will automatically detach to avoid damage.

• displacement measurementUsually installed on a screw or motorPhotoelectric rotary encoderrealization. The rotation of the screw drives the movement of the crossbeam, and the encoder records the number of rotations, which are converted into linear displacement through pitch conversion. This is the key to position feedback in the control system.

2. Drive system: the "executing mechanism" of power
Modern tensile machines commonly useServo closed-loop drive systemThe system receives speed or position commands from the controller, drives the servo motor to rotate, and after deceleration through a synchronous belt or gear, drives high-precisionball screwRotate to drive the crossbeam to move up and down. The servo motor is equipped with an encoder, which provides real-time feedback on the actual speed and position, compares and corrects it with the command, and forms a closed-loop control to ensure the stability of speed and the accuracy of position.

3. Control system and data processing system: intelligent "brain"
The control system is the command center of the testing machine. Users can set parameters such as test type, speed, and stopping conditions through computer software. The controller (such as PLC or multi axis motion controller) controls the operation of the drive system in real time based on these instructions, and synchronously commands the data acquisition card to capture the signals of the measurement system.
All raw signals (force, deformation, displacement) are collected into a computer and processed in real-time by professional testing software according to relevant standards (such as GB/T, ISO, ASTM),Automatically draw force displacement, stress-strain and other curvesAnd calculate key performance indicators such as tensile strength, peel strength, and elongation at break. Ultimately, the software can generate standardized and traceable test reports, greatly improving the efficiency and credibility of data processing.

frequently asked questions

1. Question: How to judge whether the value sensor is suitable when choosing a tensile testing machine?
Answer: It mainly depends on two key parameters:rangeandprecisionThe measurement range should cover between 10% and 90% of the expected force value of the tested material, in order to obtain measurement resolution. Accuracy is usually expressed as a percentage of full scale (e.g. ± 0.5% FS). For materials that require testing for small forces, such as thin films and fine wires, specialized sensors with smaller ranges or higher resolutions should be selected.

2. Question: Why is it necessary to use an extensometer when testing certain materials instead of directly using beam displacement instead of deformation?
Answer: The displacement of the crossbeam includes multiple factors such as sample deformation, fixture slippage, machine frame deformation, and even clearance, and cannot represent the true deformation of the sample. Especially when measuring materialsmodulus of elasticityThe measurement error of small deformations can have a significant impact on the results. The extensometer directly contacts the gauge length of the specimen, and the measurement results are true and reliable, making it a tool for obtaining accurate elastic segment data.

3. Question: What is the difference between servo motor and ordinary AC motor drive?
Answer: The main difference isControl accuracy and response speedOrdinary AC motors (variable frequency speed regulation) with open-loop control have poor speed stability and are prone to shaking at low speeds.servo motorBy adopting closed-loop control, extremely precise speed, position, and torque control can be achieved, with fast response and smooth operation at any speed. This is crucial for maintaining a constant testing rate according to standard requirements.

4. Question: What advanced functions does the software system of the testing machine have besides generating reports?
Answer: Modern intelligent software has powerful functions that far exceed basic data recording. For example:Customize a complex multi-stage testing process(such as stretching holding re stretching);Perform statistical analysis on bulk samples(CPK calculation, etc.);Automatically switch calculation models based on different standards；Trend analysis and comparison of historical test dataProvide in-depth insights for process improvement.

This document aims to provide a universal interpretation of the technical principles of electronic tensile testing machines for learning and reference. The specific operation, maintenance, and application judgment of the equipment must strictly follow the manual provided by the equipment manufacturer. If there are any updates or discussions on the information in the article, please feel free to communicate.