PORON Cushioning Blog Blog

PORON Cushioning Blog

The Squeeze Test: Using Your Fingers As An Instran When Selecting Cushioning Materials For New Product Designs

Posted by Anurag Tihaiya on Tuesday, July 9th, 2013 | No Comments »

Invariably, when someone touches a sample of foam, their first reaction is to squeeze it.  Even though this tactile test seems simple, it can help you learn a lot about a material.  But there is also underlying information that should be taken into consideration when selecting cushioning materials for new product designs.

Sensation –  The Touch

The first thing you’ll notice when you begin to squeeze a nice block of PORON® foam is how soft it is. Foam experts use a tool called a CFD (Compression Force Deflection) curve to describe how soft or how firm materials are. Below is a CFD curve of PORON Slow Rebound Very Firm (denoted as SRVS – a custom contouring, memory foam) and PORON Performance Cushioning (denoted as F – a shock absorbing foam).

 

CFD curves for PORON Materials

The x-axis is the strain – the change in thickness of the product divided by its original thickness – and the y-axis is the stress – the amount of pressure your hand is exerting on the foam. The blue line represents how an SRVS foam compresses due to pressure, and the red line represents how an F foam does.

Notice how the SRVS material exerts less pushback force in the initial portion of the curve, despite reaching its max compression at a lower strain than the F material. I would characterize the SRVS material as being softer, while the F foam is more compressible.

If someone were to squeeze these foams, they would immediately feel the difference in softness, but they may not notice the difference in compressibility off the bat. These two factors are important when selecting cushioning materials for new product designs.

For example, the PORON Slow Rebound Very Soft Material would be an excellent choice for custom contouring insoles that are designed to distribute pressure over the surface of the foam, providing comfort to the wearer during low strain activities such as walking.

PORON Cushioning Slow Rebound Material

PORON Cushioning Slow Rebound Material

On the other hand, the PORON Performance Material would be a better option for insoles designed to absorb larger amounts of shock, such as running shoes.  Since the Performance material is more compressible, it would have a greater ability to withstand larger amounts of pressure without bottoming out and provide comfort and shock absorbency with each stride.

So the next time you pick up a piece of performance foam, give it the squeeze test and see what happens!

 

Anurag Tihaiya

Anurag Tihaiya

Group Leader - New Product Development

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