Mechanical tests
Discover some of our methods.
Tensile strength, flexural strength
In a tensile test (destructive material testing) according to DIN EN ISO 527-1, the force and change in length of a sample are measured as a function of the applied elongation. This measurement can also be carried out at a defined temperature (-35 to +250°C). The tensile test is used to determine the modulus of elasticity, the tensile strength and the elongation at break of a material. Changes in these material properties after artificial aging or exposure to media are also interesting.
In a bending test, the sample is subjected to quasi-static pressure. In the 3-point bending test according to DIN EN ISO 178, the test sample is positioned on two supports and loaded in the middle with a test stamp. Areas of application here include determining the bending modulus, the bending strength and more.
Impact strength, notched impact strength
In an impact test according to DIN EN ISO 179-1, the resistance of a material to impact (dynamic) stress is determined. In the notched bar impact test, the workpiece is notched before the test, which creates increased stress peaks at the notch.
A pendulum hammer with a certain kinetic energy hits the back of the sample and breaks it. This test can also be carried out at defined temperatures. Low temperatures increase the brittleness of the material (cold brittleness).
Printing
forming residue
The compression set is an important parameter for elastomers that are used as seals, for example. The test specimen is first compressed to a certain proportion of the thickness and fixed at a constant compression set. This state is maintained for a defined time, whereby additional influencing factors such as increased temperature can act on the test specimen.
After the load is removed, the permanent deformation is measured. If the remaining compression deformation is too high, the seal's effectiveness could be limited.
Tear strength
In the tear propagation test, a defined defect is introduced into a test specimen, for example by means of a knife cut. The test specimen is then loaded at this point and the force measured as the crack propagates. The measured force provides information about the tear resistance of the material. The test is usually carried out according to DIN ISO 34-1 on elastomers for seals and according to DIN EN ISO 8067 on foams.
The tear resistance of film packaging is particularly important. The test according to ISO 34–1, ISO 6383–1, EN 495–2 and DIN 53363 simulates the film behavior when a package is opened. Ideally, the tear force and the tear force are the same - this allows a film bag to be opened in a controlled manner and the contents removed. If, however, the maximum force until the sample tears is relatively high, the tearing can suddenly continue after the first tear. For the end user, this usually leads to accidental spilling and thus often to a loss of the contents. In addition, the packaging becomes unusable and cannot be resealed.
Adhesive strength and peel strength
The peel strength, i.e. the resistance of a surface structure to detachment, is of particular interest for films, fleeces, carpets, upholstery fabrics and adhesive tapes. Depending on the application and test standard, the adhesive force can be peeled off at a peel angle of 180°, 90° or at any other angle.
Similarly, roller devices can be used to maintain defined peel angles, for example in the roller peeling test according to DIN EN 1372 with a 90° peel angle or in DIN EN 1464 with a 60° peel angle.
