Have you ever wonder about the hardness of plastic? The hardness test is a process or method used to measure the hardness of different materials. In simple words, the hardness of any material refers to its level of resistance to permanent indentation.



In this era, everything is made from plastic, and usage of plastic is growing on a daily basis.


Types of plastic

The quality of any material used in manufacturing goods is very important, and if the material you use is of low quality, then it will affect the performance.

Raw plastic has many different shapes and types, and the test is depended on the form of plastic that you want to test. In basic term, there is two variable used in the plastic, cure, and mix. Hardness testing can be easily done on both variables to verify them.


There some other forms of plastic such as thermos-polystyrene, cellulose acetate, Formica, thermos- plastics, and Plexiglas that are common for hardness testing of plastic.

Hardness testing for plastic

Hardness testing for the plastic is very simple, in hardness testing for plastic an external force is applied to it to check its resistance.


It is time to measure the depth of the indenter on the sample material, how far does indenter penetrates the plastic.


If the indenter deeply penetrated in the plastic material, then it is termed as soft plastic, and if the indenter failed to penetrate in the plastic, then it is extremely hard plastic.

You can easily calculate the hardness level by measuring the indenter depth. It is a common and very simple method of testing the hardness of the plastic.

Cause of hardness testing failure

There are many reasons that the hardness testing of the plastic failed to give the correct results. Hardness testing is very easy and simple but requires the proper training to perform the test.





Types of the hardness of plastic

There are three different types of hardness test used for testing the hardness of the plastic. In the scientific term, these three hardness tests are D2240, ASTM D785, and E384/E92. In general terms, these three tests are known as shore- durometer-hardness, Rockwell hardness, and Knoop & Vickers test.


The most common method of testing the hardness of the plastic used worldwide is the Rockwell hardness method. ASTM hardness method is used in the United States, and they prefer this testing for every product, whether it is imported or for export. Rockwell hardness testing is known for the higher standard materials.


In the ロックウェル硬さ試験, the ball indenter is used to penetrate the plastic to know its resistance. In the common test, the ball indenter with a force range from 15 to 150 kg is used.

The ball with the diameter of 1/8-, ¼- and ½- inch indenters are used.

The Rockwell test for the plastic is the same as the normal test for the plastic hardness test. There is the only difference between dwell and recovery time due to the characteristics of the plastic.

The uniqueness of hardness of plastic

There are many different materials used in the production process; most of them have similar physical properties and have the same testing criteria.

Testing of plastic is unique from other materials because plastic has different viscoelasticity and time-dependent effects. These things must be considered before measuring the hardness of the plastic.

Analyze the tests of the hardness of plastic