Rubber Hardness Testing
The measure of hardness, applied to
rubber and plastic, is a measure of
stiffness obtained from an indentation test.
An indentor is pressed into the sample under a given force and the resulting indentation, with the load applied, is measured.
Hardness is a measure of stiffness
or modulus, which is an important
property of rubbers in almost all
applications. Its popularity is due to
its practical simplicity, versatility in terms of the test piece required and
non-destructive nature. Because of
this, it is universally used as a quality control test, for troubleshooting, as a classification parameter for both compounds and products and as a requirement in material and product specifications. Hardness is widely used as a convenient, non-destructive measure of the state and uniformity of cure of a range of vulcanized products. It can also be used to track ageing, contamination and porosity and so is suitable for diagnostic purposes.
Gibitre produces hardness units for
the most commonly used hardness scales for Shore (A, D, A0, 00) and IRHD (Micro, Normal, Hard. Low).
Different configuration have been developed to meet the specific requirements of the customers:
Single hardness units
Multi-head hardness units
Both single units and multi-head units can be used in connection with a standard pc or can be controlled by an electronic console.
All the units can be equipped with centring devices to ease the control of parts with specific shapes.
Characteristics of Gibitre automatic hardness testers
High technology sensors have been
selected both for Shore and for IRHD units to ensure repeatable and long-time stable readings.
The lifting movement is controlled with a ball screw system, which ensures extremely long duration to the system.
The position of the testing unit can be manually regulated to enable the test of samples with thickness up to 300 mm.
Multi-point automatic testing
The sample holding plate has a double motor controlled movement: it moves up and down and rotates. The combination of the two movements permits to perform automatically more tests in different points of the sample.
The user can set the number of tests
and the rotation angle of the sample
between one test and the next one.
Construction technology for IRHD Testers
For all Gibitre IRHD units, the weight applied to the sample is controlled using a load-cell-closed-loop system. This technology, widely used for hardness testers for metal, eliminates the effect of friction and increases test repeatability.
The main parts of the instrument are:
the testing unit, the lifting system
and the electronic card. Those parts
have been specifically designed to
enable independent and easy replacement in case of failure.
This characteristic ensures quick
failure recovery and low-cost maintenance.