IRHD

IRHD hardness is measured by pressing a standardised indenter into the surface of the material. The indentation depth and the applied force are converted into a hardness value. The IRHD scale ranges from 0 (very soft) to 100 (very hard).

Measuring methods

• Normal IRHD: for thicker samples (2 mm or more), used for standard applications.

• Micro IRHD: for thin samples or small components that are more sensitive to the indentation force.

• Macro IRHD: for thicker and larger materials to which higher forces can be applied.

IRHD hardness testing has the following characteristics:

• Gentle on the material: only minimal deformation and damage to the sample.

• Precise: suitable for consistent and reproducible results.

• Versatile: applicable to a wide range of elastomers and soft plastics.

• Standard-compliant: complies with international standards such as ISO 48-4.

IRHD measurement is used in numerous industries and applications:

Rubber and elastomer industry

• Material testing: ensuring that the hardness meets the specifications.

• Product development: evaluating seals, damping elements and rubber profiles.

Automotive industry

• Tyres: hardness measurement to optimise grip and durability.

• Rubber components: testing mounts, seals and hoses.

Medical technology

• Soft plastics: testing materials for tubes and seals.

• Prostheses: ensuring material elasticity and hardness.

Electrical engineering

• Insulators: hardness measurement for rubber materials in cables and connectors.

• Sealing materials: evaluating heat- and pressure-resistant materials.

IRHD hardness testing offers numerous advantages:

• Standardised results: internationally recognised and comparable with other test methods.

• Flexibility: suitable for different material types and thicknesses.

• Reproducibility: high accuracy in repeated tests.

• Gentle on the material: minimal damage to the tested sample.

Although IRHD measurement offers many advantages, there are also challenges:

• Sample requirements: the thickness and size of the sample must meet certain criteria.

• Instrument calibration: regular calibration of the test equipment is required to ensure accurate results.

• Material variations: elastomers can show different hardness values depending on temperature and composition.

IRHD and Shore hardness are the most common methods for measuring the hardness of elastomers. Here is a comparison of the two systems:

Criterion	IRHD	Shore hardness
Measuring scale	0 to 100	0 to 100
Indenter	Hemispherical	Pointed cone or truncated cone
Area of application	Elastomers, soft plastics	Wide range of uses, including harder plastics
Accuracy	High, especially for elastomers	Good, but depends on the material

• Which standard governs IRHD measurement? IRHD measurement is defined in ISO 48-4.

• Is IRHD the same as Shore hardness? No, both methods measure hardness, but they use different indenters and scales.

• What sample thickness is required for IRHD measurement? Standard IRHD measurement requires a sample thickness of at least 2 mm.

• Can IRHD be used for hard materials? No, IRHD is specifically suited to elastomers and softer materials.

IRHD measurement is an indispensable method for evaluating the hardness of elastomers and soft plastics. It provides precise, reproducible results and is used worldwide in various industries. Whether in the automotive industry, medical technology or electrical engineering, IRHD ensures quality and conformity in material testing.