Universal testers are devices that apply stress to a material in order to measure its strength. They are most commonly associated with the measurement of tensile (stretching) and compressive (crushing) strength, but they can also assess other forms of stress resistance, including shear, flexion, tear and peel. As their name suggests, universal testers can assess a wide variety of mechanical properties on almost any solid material, ranging from hard samples, such as metals and concrete, to soft samples, such as rubber and textiles.

The loading unit is a central part of a universal tester. It contains a column with a rotating ball screw that drives a load-bearing crosshead. The crosshead has a tapering slot in the center where tensile jaws, clamps or other grips can attach, depending on the application. Single column machines (also known as C-frame testers because of their shape) are typically used on a benchtop and are capable of applying loads of less than 1,000 lb. Dual column machines (also known as H-frame testers) are more popular, capable of applying a load ranging from about 500–100,000 lb. There are also four-column models available. As part of the loading unit, some models have a conditioning chamber for the sample that features adjustable temperature, humidity and pressure.

Universal testers also have a control panel that contains a power unit, load measuring unit and control device. Some machines use an electromechanical motor to power the device, while others use hydraulics. The former is generally capable of a wider range of speeds and longer crosshead displacements, while the latter type is more cost effective for generating higher forces. The measuring unit measures the force of the load, usually through the displacement of a pendulum. The controller can be a simple standalone unit or PC based. A PC-based device is more apt for R&D labs since it has greater capability for modifying test variables and analyzing data.

The market for universal testing machines is driven by core manufacturing needs for characterizing materials. They are essential for selecting the right material for an application, inspecting the quality of a material, determining the properties of an unknown material or confirming it meets industry standards.

The leading manufacturer of universal testers is Instron, a subsidiary of Illinois Tool Works. Its electromechanical testers include the 5900 Series for R&D labs and the 3300 Series for QC labs. They also offer numerous larger models that employ static hydraulic technology. MTS Systems, Shimadzu and Zwick Roell are the other top suppliers.

The total market for universal testers was about $400 million in 2015. Although demand will be offset by weakness in the metals sector, the automotive and polymers industries are still expected to drive sales in the near future, resulting in mild-to-moderate sales growth.

Universal Testers at a Glance:

Leading Suppliers

• Instron (Illinois Tool Works)
• MTS Systems
• Zwick Roell

Largest Markets

• Aerospace and Automotive
• Metals
• Polymers

Instrument Cost

• $25,000–$550,000