ISO 604 Compressive Properties of Plastics
Standard At A Glance
- ISO 604
ISO 604 is an international standardized test method used to determine the compressive properties of rigid and semi-rigid thermoplastic or thermoset materials. Using compression platens to apply a force, the properties obtained are compressive strength, strain at compressive strength, compressive yield stress, and if required, modulus. ISO 604 is used alongside its tensile test standard equivalent, ISO 527, which together provide the fundamental material properties of polymers that are found in every industry and even every household around the globe.
Materials Testing System
Depending on the maximum expected forces, ISO 604 can be performed on either a single column or dual column universal testing machine such as those available in Instron's 6800 or 3400 Series. Compression platens with integral spherical seats are ideal for ensuring platen to platen parallelism, which is a requirement within ISO 604.
|ISO 604 Test Setup|
|1)||3400 Series Universal Testing System
|2)||Bluehill Universal Dashboard (2490-696)
|3)||2530 Series Load Cell
|4)||2501 Series Compression Platens
ISO 604 Platens and Accessories
Depending on your application, the following fixtures are commonly used for ISO 604 testing:
- upper compression platen with integral spherical seat (diameters vary from 2" to 8”)
- lower rigid platen of matching size
- 2601-04X series LVDT (linear displacement transducer)
- LVDT mount for platens (2601-071)
Strain MeasurementThe preferred method of measuring strain when performing ISO 604 testing is by fixing an extensometer to the platens or the specimen itself. The instrument used must have 1% accuracy or better over the region it is being used. The LVDT is the recommended strain device for ease of use, but alternatively a small gauge length (0.5 inch or less) clip-on extensometer that will fit between the platens can be used during a modulus test. However, the preferred specimen dimensions of a compressive strength test do not allow for the use of a clip-on extensometer. If not using an extensometer, nominal compressive strain is to be measured using the distance between the platens and the test frame’s crosshead position. When calculating nominal strain, machine compliance must be corrected out of the frame’s displacement measurement. A complete explanation of compliance correction can be found in an annex of ISO 604 as well as this Instron whitepaper.
|ISO 604 Accessories|
|1)||Self-Aligning Spherical Seat
|2)||Anti-Buckling Support Jig
|3)||2601-04x Series LVDT|
Helpful Tips and Tricks
- The ISO 604 method is included in the Plastics test method suite in Bluehill Universal.
- If the specimen is too thin, an anti-buckling support jig should be used to prevent the specimen from buckling.
- If reporting the modulus calculation, make sure the extensometer and load cell are both verified in the range where the calculation is being made. Labs commonly make the error of reporting calculations outside of the verified range of their devices.
Instron 6800 Series Universal Testing Systems provide unparalleled accuracy and reliability. Built on a patent-pending Operator Protect system architecture with an all-new Smart-Close Air Kit and Collision Mitigation features, the 6800 Series makes materials testing simpler, smarter, and safer than ever before.
Bluehill Universal Software is built from the ground-up for touch interaction and an intuitive user experience. Discover simpler and smarter testing with features such as pre-loaded test methods, QuickTest in seconds, enhanced data exporting: and Instron Connect – a new feature that provides a direct communication link to Service. Users of previous versions of software such as Bluehill 2 and Bluehill 3 can easily upgrade to the newest version of Bluehill.
This anti-buckling fixture is designed for compression testing of rigid plastics and the shear testing of reinforced plastics. It has also been adapted for use with high strength composites.
These easy-to-install compression platens are precisely machined fixtures that are designed for even distribution of compression loads during a test. The compression load string comprising an upper platen with integral spherical seat and lower rigid platen is attached to the loading axis of the universal testing machine.