What Is Durometer Testing?

Durometer Testing   

            Conducting a durometer test involves assessing the hardness of a material using a specialized instrument known as a durometer. This test primarily applies to non-metallic materials such as rubber and plastic. Understanding a material’s hardness is crucial for selecting the best option for specific applications, as it directly influences performance characteristics. However, it’s important to note that this test does not measure wear resistance.

            The durometer scale provides a standardized reference for evaluating materials. This test helps describe a material’s resistance to indentation, offering insights into its hardness. Essentially, it serves as a quick assessment of how the material will perform under compression, impact, or abrasion conditions, enabling informed decision-making in material selection.

What are Shore scales?

            After measuring the hardness of a material, you can determine its position on the durometer scale, which consists of 12 different scales. The most used scales are Shore A and Shore D. Shore A is used for softer rubbers, while Shore D is suitable for harder rubbers. For example, a rubber nipple for a baby bottle typically falls within the Shore A category, while a grocery cart wheel would classify under Shore D.

            There isn’t a one-size-fits-all method for measuring hardness in flexible rubbers. Although the scales provide a valuable reference for evaluating rubber and plastics, each has its differences. Shore A hardness scale is generally used for bendable rubbers. This scale effectively measures the material’s strength, which can vary significantly. The data obtained is invaluable for engineers, offering critical insights that can be utilized in design and application.

Performing the Test

1. Place the material on a flat, hard surface.
2. Position the durometer so the indenter makes contact with the material
3. Firmly push down until you achieve solid contact.
4. Take a reading.

        Durometer testing is an effective method for distinguishing between different rubber products. It helps with quality control and grouping materials based on their performance. Although the hardness values obtained from the Shore scales may not directly correlate with other important characteristics of rubber or plastics, such as strength, abrasion, resistance, or compression set resistance, they are related to the material’s stiffness when bent. Therefore, shore hardness and flexibility can be essential factors to consider when planning for applications, and they can’t be further validated through additional testing.