ISO 178, ASTM D790

ISO 178 and ASTM D790 norms deal with the determination of the flexural properties of the unreinforced plastics

Among the most commonly used in the sector, they allow the determination of the maximum stress, flexural modulus and others related to a particular state of stress.  The fixture allows a 3-point bending, where shape and distance of the anvils are in compliance with Standards. 

Test consists in positioning the specimen on a crosshead with two points of support and gives a deflection on a punch which presses on the centerline of the specimen, thus generating a bending of the specimen itself. The use of an additional reading device of the maximum deflection in the central point is always recommended if the elastic modulus has to be calculated.

Tested materials: thermoplastic dies and extrusion materials, including reinforced and loaded compounds, in addition to the not loaded types, thermoplastic rigid sheets, thermosetting materials for dies, including reinforced and loaded compounds, thermosetting sheets. For reinforced materials it is advisable to evaluate other types of standards such as ISO 14125 and ASTM D6272.

Both 3 and 4-point flexural loading devices are used to evaluate plastics. The loading and the dimensions of the anvil support can differ from the specimen thickness. We use the software Labtest preload characteristic to determine the loading start, at this point, the strain measurement devices can automatically re-balance. The load supported by the specimen is measured during this procedure.

Flexural devices are designed to be mounted on benchtop or floor standing Quasar machines equipped with software Labtest where specimen data, automatic control of the test according to Standard parameters, automatic calculation of the results and statistical analyses for the tested material qualification will be entered.