Plastic testing: These methods deliver reliable results

Why plastic testing is indispensable

Materials

have become indispensable in numerous industries – from

mechanical engineering

and

electronics

through to

medical technology

. Their versatile properties such as low weight, high strength, elasticity or chemical resistance enable tailor-made solutions. But it is precisely this diversity that makes it necessary to test the materials used precisely. Plastic testing is a central instrument for ensuring quality, functionality and safety. It serves material characterisation, process control and product release. Only through reliable test methods can material defects be detected at an early stage, processing processes be optimised in a targeted manner and industry-specific standards be reliably complied with.

Mechanical testing of plastics

Mechanical testing analyses the load limits and deformation behaviour of a plastic. The results provide important characteristic values for the design, dimensioning and application assessment of components under real conditions.

Tensile test

In the tensile test, a standardised plastic test specimen is slowly stretched until it tears. The characteristic values determined in the process, such as tensile strength, yield point, modulus of elasticity and elongation at break, provide detailed information about the plastic and elastic behaviour of the material. The test simulates stresses such as those that occur in practice under tensile load – for example in housings, cable ties or technical profiles.

Compression test

The compression test examines the reaction of a plastic to a uniaxial compressive load. This method is particularly relevant for components that are subjected to compressive stress – such as bearings, seals or insulating sleeves. The compressive strength values obtained help to realistically assess the risk of deformation or failure under load.

Flexural test

In the flexural test, the plastic is loaded in a three-point or four-point bending configuration. Flexural strength, flexural modulus and behaviour up to break are measured. The method is particularly suitable for sheets, pipes or fibre-reinforced plastics that are to be tested for deflection or flexibility.

Impact strength test (Charpy notched impact test)

This test examines the fracture behaviour of a plastic under sudden load. A pendulum-like striker hits a standardised specimen with a defined notch. The energy expended up to break is measured – an important value for safety-relevant applications, such as bumpers, helmet parts or housings.

Thermal test methods

Thermal tests provide information about how a plastic behaves under heat, cold and changing temperatures. They are central to the design of components that are exposed to thermal load.

Thermogravimetric analysis (TGA)

TGA measures the mass change of a plastic as the temperature rises under a controlled atmosphere. This allows conclusions to be drawn about decomposition temperatures, filler contents or thermal stability. This method is a standard, particularly in material development and ageing analysis.

Dynamic mechanical analysis (DMA)

DMA determines the viscoelastic behaviour of a plastic as a function of temperature, time and frequency. A periodic load is applied and the resulting deformation is measured. The method provides precise information on damping, glass transition and moduli – essential for elastic applications and complex load situations.

Differential scanning calorimetry (DSC)

DSC measures the heat flows that a plastic absorbs or releases under a controlled temperature change. Melting points, crystallinity, glass transitions and reaction enthalpies are determined. These values are decisive for processing (e.g.

injection moulding

), thermal load capacity and shelf life.

Hardness and surface tests

These methods assess the surface hardness and microstructure of a plastic – important factors for scratch resistance, abrasion behaviour and mechanical load capacity.

Shore hardness test

The Shore hardness test determines the penetration depth of a test body into the plastic surface. Depending on the hardness range, different scales are used – Shore A for soft, Shore D for hard plastics. The method is fast, standardised and practical – ideal for series inspection and material selection.

Martens and Vickers hardness

These microscopic methods provide more precise hardness values, particularly for small components or thin-walled structures. They are used when Shore methods are not sufficient, for example with high-performance engineering plastics, coatings or composite systems.

Scanning electron microscopy (SEM)

SEM provides high-resolution images of fracture surfaces and surface structures. This makes it possible to visualise manufacturing defects, voids, cracks or fibre orientations. SEM is a valuable instrument in damage analysis or when assessing additive effects.

Further analysis methods

• FTIR spectroscopy: Identifies plastic types and additives by their specific infrared spectra – ideal for material identification and quality assurance.
• Rheometry: Measures the flow behaviour of melts under shear – indispensable for the design of extrusion or injection moulding processes.
• Density determination: Simple but informative – for differentiating similar plastics and for quality inspection.
• Colour analysis and transparency tests: Relevant methods for optical applications, for example in medical technology or consumer goods production.

Our service: plastic testing for industrial applications

We offer comprehensive plastic testing in accordance with internationally valid standards (DIN, ISO, ASTM). Whether you need mechanical characteristic values, wish to test thermal load capacity or want microscopic examinations carried out – our laboratories provide you with reliable, traceable results. Our experienced team supports you competently in material development, quality assurance or damage analysis.

Get in touch – we will be happy to advise you individually and develop a suitable testing concept for you.