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The compression set test is the rubber’s ability to come back to its original thickness or shape. It is tested after squeezing it for a long time. These tests are conducted at high temperatures because they want to simulate real working conditions. Performance of the end rubber part is recorded after the test. Each rubber type has to be tested under a specific temperature and for a particular time. There could be a variation if it is a specific need.

Due to constant compression load, physical change happens in elastomeric material. It cannot return to its original size after release. The amount of material that cannot return to its original size is called a compression set.

Both static and dynamic seals find this kind of failure. Due to the compression set failure flat surfaces produce on both sides of the O-ring’s cross-section. It reduces the sealing potential and efficiency.

What is the reason behind compression set failure?  Here are some of the causes.

  • The choice of elastomer is incorrect. It has poor compression set properties.
  • The material shows low heat resistance.
  • There is excessive swelling of material in the system fluid
  • Excessive squeeze is needed to achieve the seal
  • Vulcanization or incomplete curing of O-ring material during production

What could be the solutions if you experience a compression set. Here are some solutions.

  • Use of low set elastomer
  • Use of O-ring material that resists heat generated due to operation and friction
  • Check the compatibility of the material with system fluid and chemicals
  • Reduction in O-ring squeeze as much as possible
  • Checking O-rings for right physical properties

It is essential to set formulas for calculating the minimum and maximum O-ring compression. When you are stuck somewhere, the best thing is to ask some expert.

Nowadays, it is easy to get help online. Enroll into some authentic site and get the desired information.

Choosing the right material is the key for seal setting

You should understand how the elastomeric material will behave when you select the material. There are several elastomers in cellular and solid formats. You can pick one by picking the most appropriate methods and by knowing the fundamental properties of the material.

The process of selection can be made easy by reducing the choices based on the above research. Once it happens then a solution development process can be initiated around the particular application. It involves mating surfaces that are supposed to be sealed. Other parameters are airflow, pressurized air, gases, fluids, and so on. The surfaces will affect the choices.

Leak-Pack is ISO 9001:2008 certified company and leading mechanical seals manufacturer & supplier in India, providing solutions to all types of leakages by manufacturing Mechanical Seals and Sealing Components as per customer’s drawings, samples or requirements. To know more about Mechanical Seal call on +91-(2739) 271592 or email at

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