SAUTER HBA 100-0 Analogue Shore hardness tester, Shore A, drag-type indicator

Mechanics of Shore A Indentation Hardness

In the quality assurance of polymers, rubbers and elastomers, the macroscopic determination of hardness is a key metrological task. The SAUTER HBA 100-0 is a precise, analogue testing instrument for determining material hardness on the Shore A scale (in accordance with DIN ISO 48-4 / ASTM D2240). The physical measuring principle is based on the material’s resistance to penetration by a defined indenter. In the HBA 100-0 model, this indenter is geometrically designed as a truncated cone with an exact opening angle of 35°. It is pressed into the material under test with a defined contact force by means of a precisely calibrated steel spring – based on Hooke’s law. The mechanical penetration depth is inversely proportional to the material hardness: deep penetration of the indenter results in a low Shore value (soft material), whilst high resistance generates a high Shore value (hard material) on the dial.

Viscoelasticity and peak hold via a mechanical drag pointer

A fundamental phenomenon in the physics of materials relating to amorphous polymers and elastomers is their viscoelasticity. When mechanical stress is applied by the test specimen, the material immediately begins to relax due to molecular chain displacement (creep behaviour). The displayed hardness value therefore decreases continuously within the first few seconds of the measurement. To record the maximum initial value (peak) required by the standard absolutely accurately before material relaxation sets in, the SAUTER HBA 100-0 is equipped with a mechanical drag pointer function. A second, red indicator hand is pushed to the maximum deflection by the main hand and remains in this position. The user can therefore read the exact peak value conveniently and without parallax once the measurement is complete.

Self-sufficient metrology for harsh industrial environments

Opting for a purely mechanical, analogue measuring system offers significant advantages in harsh industrial field applications. The HBA 100-0 requires neither batteries nor electronic sensor calibrations and is therefore always ready for use independently. The sensitive mechanical conversion of the penetration depth into a rotational movement of the pointer is enclosed in a solid metal housing, which protects the precision mechanics from impacts and dust. The instrument is ideally suited for the non-destructive testing of soft rubber, neoprene, silicone, vinyl, felt and leather directly on the extrusion line or in the goods-in department.

Reproducibility through standardised test benches

In manual, free-hand measurements, the operator’s individual indentation speed and indentation force represent the greatest sources of physical error. To ensure absolute metrological reproducibility and to meet the strict repeatability tolerances of ISO standards, the housing of the HBA 100-0 is designed for direct adaptation to a standardised Shore test rig. The use of a test rig with a constant test weight fully standardises the kinematics of the measurement.

Technical details

• Physical measurement method: Shore A (indentation hardness)
• Indenter geometry: truncated cone with a 35° opening angle
• Dynamic measurement range: 0 to 100 HA (Shore A)
• Metrological resolution (d): 1 HA
• Analogue display: High-contrast dial
• Peak function: Mechanical tracking pointer for recording peak values
• Material compatibility: elastomers, rubber, neoprene, silicone, felt, leather
• Power supply: Battery-free (purely mechanical system)
• Housing construction: Solid metal housing
• Compatibility: Designed for mounting on mechanical test rigs
• Compliance with standards: In accordance with DIN ISO 48-4 / ASTM D2240

Contents of supply

• 1 x SAUTER HBA 100-0 analogue Shore hardness tester
• 1 x Sturdy storage box
• 1 x Detailed operating instructions

Individual requirements & accessories

To eliminate the human factor from the force-displacement equation used in Shore measurements, we strongly recommend that certified quality assurance laboratories use a manual test rig (such as the SAUTER TI-AC). This applies the standard load precisely and lowers the test block onto the material sample at a perfectly orthogonal angle. For the regular verification of the mechanical spring constant in your laboratory, we also offer standardised Shore A reference plates. Our procurement service, which specialises in materials science, will be happy to configure a test setup for you that complies with the relevant standards.