ISO 868

Hardness Testing for Plastics and Ebonite

ISO 868 is the standard testing method for determining the hardness of plastics and ebonite. It is an industry accepted method that uses indentations and durometers to assess the hardness of a given material. It’s intended primarily for control purposes and can be a crucial part of any QA process for products involving plastics or ebonite.  

The ISO 868 method

This testing method uses a durometer to measure the indentation resistance of elastomeric or soft plastic materials after force has been applied to a conical indentor. The shape of the indentor varies depending on the softness of the material being tested. A durometer A has an indentor with a blunted tip and is suitable for softer plastics while a durometer D has a pointed tip and is suitable for harder materials.  

When durometer A results are greater than 90, it’s recommended to use D. When tests with D have results of less than 20, it’s recommended to change for A.  

Hardness values range from 0 (indicating full penetration) to 100 (indicating no penetration). ISO 868 makes use of the Shore hardness scale. 

What is the Shore hardness scale? 

The Shore hardness scale is a well-established method of determining the hardness or flexibility of a variety of materials. In the 1920s, Albert Ferdinand Shore invented a hardness scale, allowing for a common point of reference when talking about the relative hardness of materials.   

There are a selection of Shore hardness scales, including Shore A, Shore D, Shore H and Shore O, to suit different material types. Shore A and Shore D are most commonly used in the rubber and plastics industry. Find out more in our guide to the Shore hardness scale.  

ISO 868 compliant Shore hardness gauge

If you need to test the hardness of plastics or ebonite and want to know that your results will meet the standards required for ISO 868, we can help. Our testing solutions are designed with relevant regulations in mind. For hardness testing, one such recommended solution is the: 

TQC Sheen Shore Hardness Gauge 

This reliable instrument measures the impression hardness of soft materials, including coatings, plastics and rubber. By applying force to a material via its standardized presser foot, the durometer measures the depth of an indentation in the sample.  

Hardness testing solutions

Whether you’re looking to add a single new element to your existing test and inspection set up or you’re in the process of creating a QA process for a whole new product, we’re happy to help with advice and recommendations. We have specialist engineers working in a variety of different sectors, from flexible packaging to automotives, so we can provide you with the expert help you need.  

Browse related ISO 868 products below and get in touch if you have any questions.