VDA 675-222 (10/2020)
VDA 675-222: Elastomer: Prüfverfahren zur Eigenschaftsbestimmung - Druckverformungsrest / Elastomer: Testprocedure - Compression Set (Version 10/2020) - Gruppenlizenz (group license), AGB (GTC) Art. 10, 2
This recommendation defines the test method to determine compression set on test pieces cut from finished parts.
This VDA recommendation corresponds mainly to DIN ISO 815-1 with following deviations:
- This test method can be applied to (almost) all rubber parts.
- This document is supplemental to the description of the test procedure in DIN ISO 815-1 and is related to the specific characteristics regarding testing on samples cut from finished parts.
In cases where it is not possible to cut suitable test pieces from finished parts for testing compression set, the state of cure must be determined with an alternative method (e.g. MNR, tension set, swelling in solvents) which must be agreed upon between manufacturer and customer.
This document can only be applied to test pieces from pure elastomers or elastomeric parts with textile reinforcement. For parts with metallic or plastic inserts, elastomeric portion must be tested separately, or a separate test must be agreed upon.
This test method does not relate to the test of permanent deformation of parts or sections from them. When testing permanent deformation, the shape of the part influences the result (e.g. deformation of sealing lips at radial lip seals).
This test method does not incorporate thickness measurement with optical devices. (Values for initial height and height after test can be higher, resulting in better (lower) compression set values.)
This test method can provide data for
- qualification tests on different elastomers which are in question for a specific application (quality determination),
- comparison tests on different delivery batches of a specific elastomer compound (quality assurance).
The tests are preferably performed with the test pieces shown in section 3.1