Scope:

Shore Hardness test by ASTM D2240 method measures the hardness of a material, specifically polymers, elastomers, plastics, and rubbers. Shore Hardness value decides the relative hardness of these soft materials. Therefore, the Shore Hardness or Durometer Hardness test is important to calculate the penetration of a particular indentor into the material under a specific condition of force and time. In addition, the hardness value is useful to ascertain the hardness of elastomers as a quality control measure on batches of materials.

Test Procedure:

Firstly, the specimen is put on a hard flat surface to carry out the ASTM 2240 test. After that, the indentor for the instrument is pressed into the specimen by keeping it parallel to the surface. Then with the firm contact of the specimen, the hardness of the specimen is read within one second (or as mentioned by the client).

Specimen size:

The test specimens are usually 6.4 mm (¼ inch) thick. Several specimens can be placed one over another to achieve the 6.4 mm thickness, but a single specimen is preferred.

Data:

The hardness scales Shore A and Shore D are commonly used to derive the score. The A scale is used for softer, and the D scale is for harder materials. 

Conclusion:

ASTM D2240 is a standard test method used to determine the relative hardness of soft materials, usually plastic or rubber.