Choosing the right universal testing machine (universal material testing machine) is crucial, and the key is to match the laboratory’s testing needs, sample characteristics, accuracy requirements, and future expansion potential, avoiding both over-specification and under-performance.

I. Clearly define core testing requirements and select the appropriate testing machine type.

The core function of a universal testing machine is to perform mechanical property tests such as tension, compression, bending, shearing, and peeling on metals, non-metallic materials, and composite materials. The following key requirements must first be clarified:

1.Test items

• If you only need to perform conventional tensile/compression tests (such as on plastics or metal wires), a basic electronic universal testing machine will suffice;
• For high-strength testing involving high-hardness materials (such as steel and alloys), or for compression/bending tests requiring large tonnage, a hydraulic universal testing machine is the preferred choice (due to its larger tonnage capacity and greater stability);
• For tensile and tear testing of flexible materials (such as rubber and films), a large-deformation extensometer and appropriate fixtures are required, and in some cases, a low/high-temperature environmental chamber is also needed.

2.Sample type and dimensions

• The sample size determines the testing machine’s travel range: for example, testing long samples (such as steel bars) requires a machine with a large travel range; testing tiny samples (such as electronic components) requires a high-precision, small-range sensor and a microscopic fixture.
• The type of sample determines the type of clamp required: metal samples require wedge-type tensile clamps (for strong, non-slip gripping); flexible materials require pneumatic clamps or specialized rubber clamps (to prevent slippage and sample damage).

3.Maximum test force requirement

• The rated tonnage of the testing machine must cover the maximum breaking force of the sample, and it is recommended that the actual test force be within the 10% to 90% range of the rated tonnage (this range offers the highest accuracy).
• Common tonnage references:
  • Electronic universal testing machine: 0.01kN~100kN, suitable for testing non-metallic materials and small-tonnage metal materials;
  • Hydraulic universal testing machine: 100kN~2000kN, suitable for testing large-tonnage metals, concrete, etc.

II. Focus on core performance indicators to ensure testing accuracy.

Laboratory testing requires a high degree of data accuracy, and the following performance parameters need to be carefully verified:

1.Force measurement accuracy

• National standards require an accuracy better than ±1%. For research-grade laboratories, it is recommended to choose models with an accuracy of ±0.5% or higher to ensure data repeatability and traceability.
• Note whether multi-sensor configurations are supported: A single testing machine can be equipped with multiple sensors of different ranges, meeting the testing needs of various samples and improving cost-effectiveness.

2.Displacement and deformation accuracy

• Displacement accuracy: This relates to the control of the travel distance during the tensile/compression process of the specimen, and is typically required to be better than ±0.5%.
• Deformation Measurement: If precise measurement of the specimen’s strain is required, an extensometer (including axial and transverse extensometers) must be used. The accuracy of the extensometer must meet the requirements of the national standard GB/T 12160.

3.Control systems and software

• By selecting a closed-loop control system (force feedback, displacement feedback, or strain feedback), smooth switching between different control modes can be achieved (e.g., switching from displacement control to force control in a tensile test).
• The software must support national/international standard testing methods (such as GB, ISO, and ASTM), and possess functions for automatic data calculation, curve plotting, report generation and export. It must also support data traceability and audit trails (to meet the compliance requirements of research and quality inspection institutions).

III. Combining laboratory conditions with expansion requirements

1.Installation and usage environment

• Electronic universal testing machines are compact and low-noise, making them suitable for typical laboratories; hydraulic universal testing machines require a fixed foundation, and the hydraulic system generates some noise, requiring sufficient space and ventilation.
• Note the power requirements: Hydraulic presses have high power consumption, so please ensure that the laboratory’s power supply meets the requirements.

2.Extensibility and compatibility

• Consider whether additional test items (such as high and low-temperature testing, fatigue testing) will be needed in the future. Choose a model that supports modular expansion, allowing for the addition of environmental chambers, fatigue testing accessories, etc., to avoid duplicate purchases.
• Does the software support data integration with LIMS (Laboratory Information Management System) to facilitate integrated management of laboratory data.

3.After-sales service and brand reputation

• Prioritize well-known domestic brands or top-tier international brands to ensure timely after-sales service (such as sensor calibration, fixture repair, and software upgrades).
• Verify whether installation, commissioning, and operational training services are provided. For research-grade equipment, it is recommended to request a calibration certificate from the manufacturer.

IV. Priority Considerations for Equipment Selection in Different Laboratories