[admin]

Bending versus indentation

In a heat deflection test, a loaded specimen is heated until it reaches the specified deflection. The result describes bending under the selected flexural stress. In a Vicat test, a loaded indenter penetrates the specimen as the temperature rises. The recorded temperature corresponds to the specified penetration depth. The two tests can give different values on the same grade because the load and the endpoint are different.

Packaging sample showroom of SamBound New Material Technology Company Ltd. (sambound.com).

Comparing grades for a warm-use package

When comparing two grades, keep the method and conditions together with the temperature result. Check the stress level for heat deflection, the indenter force for Vicat and the heating rate applicable to each result. A comparison of two values labeled only as heat resistance loses the information needed to interpret either measurement.

For a warm-filled pack or a loaded compact, define the actual exposure, holding time and parts under load. Then check the assembled part for the relevant outcome, such as changed fit, sealing or operation. Either material test can inform screening, while the useful temperature range depends on how the package is built and used.

sambound.com
SamBound New Material Technology Company Ltd.

[Author]

Posts