ISO 604 – Determination of Compressive Properties of Plastics

ISO 604 specifies a method for determining the compressive properties of plastics under defined conditions.

The method is used to investigate the compressive behaviour of the test specimens and for determining the compressive strength, compressive modulus and other

aspects of the compressive stress/strain relationship under the conditions defined.

*** The method applies to the following range of materials:

Rigid and semi-rigid thermoplastic moulding and extrusion materials, including compounds filled and reinforced by e.g. short fibres, small rods, plates or granules.

in addition to unfilled types; rigid and semi-rigid thermoplastic sheet;

Rigid and semi-rigid thermoset moulding materials, including filled and reinforced compounds; rigid and semirigid thermoset sheet;

Thermotropic liquid-crystal polymers.

For ISO 604, typical test blocks are are 50 x 10 x 4mm for modulus and 10 x 10 x 4mm for strength.

The specimen is placed between compressive plates parallel to the specimen surface.

The specimen is then compressed at a constant rate

The maximum load is recorded along with stress-strain data.

ISO 604 An extensometer attached to the fixture is used to determine the modulus of elasticity.

When performing compression testing, it has been found that specimen alignment plays an important role in achieving even load distribution, which contributes

to the consistency of the results.

*** The ISO 604 standard is technically equivalent to the ASTM D695 Standard.

*** Before conducting ISO 604  ,  it is important to read the entire specification. Standards can be obtained from appropriate standard authorities.