ADHESIVES

01 90 Degree peel fixture on a 68TM

02 2820-036 Variable angle peel fixture with screw-action grip (upper)

03 180 degree peel test 2712-05x Pneumatic side action grips

Grips and Fixtures

The strength properties of adhesives are important, and a variety of techniques are employed to test them. From seals that are intended to fail predictably and repeatably such as in packaging, to ultra-high-strength bonded structures in automotive and aerospace applications, Instron® has a range of grips and fixtures to assess the strength and peel resistance of adhesives.

Tensile tests on lap-shear specimens are commonly performed using 2710 Series screw action grips as the dual-acting design allows for an adjustable offset.

Adhesive properties are often determined using a variety of peel fixtures such as 90°, variable angle and rotating wheel. These are ideal for testing adhesive tapes of various types. The adhesion of printed circuit board foils can be determined using the 2820-101/-102 floating roller fixture, which is ideal for peeling flexible laminates from a rigid substrate.

Special fixtures for testing adhesives in wood, composites and microelectronics applications are also available. Wood test fixtures include devices for measuring the shear strength of adhesives used for timber. The climbing drum peel fixture for composites is available for both flexible and rigid substrates. Miniature peel fixtures are designed for very small specimens and low forces.

Fatigue tests on adhesive joints can usually be performed using grips from our standard range of general purpose fatigue grips.

Environmental

Adhesives are often tested under various environmental conditions. The Instron range of environmental chambers covers a wide range of conditions including high and low temperatures.

Software

Peel tests require analysis of the complex force displacement curve. Bluehill Universal or Bluehill Elements software programs contain a large number of control and analysis options relating specifically to peel tests. Fatigue tests can be performed using dynamic software programs, such as WaveMatrix™.

Common tests for metals and metallic alloys are tensile, shear, bend, impact, torsion, fatigue, as well as fracture properties. Metals are one of the most common testing materials for both electromechanical and servohydraulic systems, with materials as diverse as fine gold wire for microelectronics to steel reinforcing bar for the construction industry.

Tensile tests are performed on a huge variety of metallic materials including wire, foil, sheet, plate, bar, tube, and fasteners.

Typical tensile properties that need to be determined include modulus, yield strength, elastic and plastic strain, tensile strength, and break elongation. The strain-hardening behavior of metal sheet is of major importance to manufacturers of material used for deep drawing or pressing components, such as car bodies, where strain hardening exponent (n-value) is an indicator to materials’ performance in these end applications. Similarly, the plastic strain ratio (r-value) is an important indicator for the amount of reduction in the materials area when subjected to a tensile load, which requires axial and transverse extensometers.

To make metal production cost effective, it is optimal during high production, which in turn requires a large volume of testing to be performed in order to ship material. Efficiency of completing the required tests is therefore paramount for metals producers. Instron®’s advanced software, as well as automated accessories, can help to provide significant throughput gains. Alternatively, to fully optimize testing lab output, Instron offers fully robotic testing systems that can allow unattended operation over extended periods.

The crucial importance of fatigue and fracture behavior in applications, such as rotating shafts, axles and aircraft components, has resulted in the widespread use of dynamic tests in which forces are cycled many times to evaluate the performance of materials and components over long periods. High cycle fatigue, fracture toughness, low cycle fatigue (LCF) and specialist tests, such as thermo-mechanical fatigue (TMF), are frequently performed. In many cases these tests are also required to be under non-ambient temperatures with furnaces, environmental chambers and cryostats integrated into the testing system.

Instron metals testing solutions comply with the requirements for all major testing standards (ASTM, ISO, GB, JIS, BS, etc.). In addition, Instron actively participates in standards committees and continually tries to improve the development of those standards.