Hardness tests (Buchholz indentation test, Persoz-König hardness, Vickers, Shore A and D, …)

Hardness testing encompasses a set of mechanical methods designed to measure a material's resistance to penetration, indentation, or deformation. These tests are fundamental for the mechanical characterization of materials and are widely used in the packaging, materials, and polymer industries.

These tests allow verification of product conformity to technical specifications, comparison of formulations, qualification of materials, or control of production consistency. Depending on the nature of the material and the intended application, different hardness measurement methods can be implemented, such as Shore, Vickers, Buchholz, or Persoz-König tests.

General principle of hardness testing

The hardness of a material corresponds to its ability to withstand a localized mechanical action, usually exerted by a pendulum or indenter. Hardness tests consist of applying a defined load to the surface of the material, then measuring the depth, area, or effect of the resulting indentation.

Each method is based on a specific principle and provides a hardness value expressed according to its own scale. The choice of test depends on the nature of the material, its surface condition, its thickness, and the information sought.

Proposed testing methods

Shore A and Shore D hardness tests are primarily used for polymer and elastomer materials. Shore A is suitable for soft materials such as rubbers or certain flexible plastics, while Shore D is used for more rigid materials.

The Vickers hardness test relies on an indentation made using a diamond pyramid. It allows for a precise measurement of the hardness of metallic materials, rigid polymers, or composites, including thin sections or localized areas.

The Buchholz indentation test is primarily used for coatings and films. It involves measuring the width of an indentation left by a standardized indenter, allowing for the evaluation of the indentation resistance of coated surfaces.

The Persoz-König hardness test is a pendulum test used to characterize the hardness of coatings. It measures the oscillation time of a pendulum placed on the surface of the material, providing an indication of the film's stiffness and hardening.

Measured parameters

Hardness tests provide quantitative values ​​expressed according to the scale specific to each method, such as Shore A, Shore D, HV (Vickers), Buchholz units or Persoz-König seconds.

These results make it possible to compare materials with each other, to verify their conformity to specifications, to evaluate the impact of formulations or manufacturing processes and to monitor the evolution of mechanical properties over time.

Matrices and materials concerned

Hardness testing applies to a wide range of materials, including plastics, polymers, elastomers, rubbers, films, coatings, composite materials and some metallic materials.

They can be carried out on finished parts, test specimens, plates, films or coatings applied to substrate, provided that the test conditions are compatible with the chosen method.

Industrial applications

Hardness testing is used in many industrial contexts. It plays a role in the development of new materials, supplier qualification, formulation validation, and quality control in production.

In the packaging sector, they are used to assess the mechanical resistance of plastic materials and films. In materials and polymers, they are used to compare different formulations, verify the consistency of mechanical properties, and detect potential process deviations.

Hardness tests are also used in investigations in cases of non-conformity, mechanical failure or technical dispute.

Quality and compliance issues

Hardness measurement is a key criterion for technical compliance. A non-compliant hardness value can impact a product's functionality, durability, or safety.

These tests make it possible to document technical files, meet contractual and normative requirements and secure the placing on the market of materials and finished objects.

YesWeLab Expertise

YesWeLab relies on a rigorously selected network of partner laboratories with recognized expertise in mechanical testing. The majority of these laboratories are certified and/or accredited according to recognized standards such as ISO 17025 and COFRAC.

Each request is analyzed by the YesWeLab scientific team to select the most suitable testing method for the material, application, and technical requirements. Thanks to its digital platform, YesWeLab enables centralized test management, optimized sample tracking, and fast, secure access to results.

Since 2020, many manufacturers, distributors and design offices have trusted YesWeLab for their mechanical testing and the characterization of their materials.

Other analyses from the YesWeLab catalogue

Hardness tests can be complemented by other analyses from the YesWeLab catalogue to obtain a more complete mechanical and physico-chemical characterization of materials.

Tensile , flexural and compression tests of the overall mechanical properties of materials.

Thermomechanical analyses , such as dynamic mechanical analysis (DMA), allow the study of the behavior of polymers as a function of temperature and stresses.

Aging and environmental resistance tests complement the assessment of material durability .

analyses of polymers (FTIR, DSC, TGA) make it possible to link mechanical properties to the composition and structure of materials.

For any quote request or to discuss your specific hardness testing needs, contact the YesWeLab team now.