Examining Foam’s Density, Weight, and Firmness Characteristics Part II

Edit：http://chinaixpe.com/en   Browse：   Date：2015-11-18

Last part we talked about the desity and weight of foam, following is firmness.

Firmness, on the other hand, is reflective of the feel of foam and how it carries and yields to weight and pressure. It is measured with a value called Indentation Load Deflection (ILD). It is also known as Indentation Force Deflection, or IFD.  ILD is measured by taking a 15 inch by 15 inch by 4 inch section of foam and measuring the force in pounds that it takes a 50 square inch circular plate to compress the material 25 percent of its thickness. If a foam section requires 36 pounds of pressure to reach 25 percent compression, it has an ILD value of 36.  It is important that the material being tested adheres to the dimensions stated, as thicker and thinner cuts of the same material can deflect weight differently. A firm material will require more force to reach its compression value, and a softer material will require less force. Typical ILD values range from 8 to 70, with some materials reaching as high as 120 to 150.

Firmness testing assesses how a material will carry weight in its end-product application. Based on structural and chemical makeup, some foam sheets with higher densities can have lower ILD values than foams with lower densities. For this reason it is important to look at the two values independently and use them to match your preferences to a product. People who want firm support from hard foam would want products with higher ILD values, and people who desire comfort products with soft foam would want foam with a lower ILD.

Knowing the differences between these two characteristics and what they do and do not represent is a major factor in deciding what kind of product best fits an application. Finding where your desires fall within each value is an excellent way to pinpoint exactly what you want in a product. For more information on density, weight and firmness and how they apply to you, don’t hesitate to contact us to help you find exactly what you need. We could provide more about pe foam, xpe foam and ixpe foam etc.

 

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