Car seat manufacturers depend on the firmness of their seat cushions to provide safety, durability and comfort for customers. Manufacturers use ASTM and ISO standards as foam testing foundations to ensure quality products. Yet each manufacturer has unique requirements.
TestResources engineers can help develop testing plans and equipment to cover all flavors of foam testing. To begin, it is important to know that each test is slightly different but falls into three major categories: IFD & ILD testing, hysteresis testing and bolster testing.
IFD & ILD Testing
Car seat cushion firmness is measured by a physical property called the indentation force deflection (IFD or ILD). This property is defined by the amount of force, in newtons, that is required for a compression test machine to press a round indenter foot or compression platen into a specified thickness of a foam specimen.
Car seat foam testing typically requires several repeated tests to the middle and back of the car seat to confirm consistent firmness throughout the complete seat assembly, therefore TEST efficiency is an important factor when purchasing test equipment. TestResources programmable IFD tests feature a reduced test time duration from 15 minutes to as short as 1 minute based on the versatility of our software.
TestResources 370 Series ILD Foam Testers deliver accurate ILD firmness readings for foam and foam product applications. The 370 Series Indentation Load Deflection or ILD test machines are also fitted with the compression platens that will help you meet your particular requirements.
Hysteresis Testing
Hysteresis tests are another option for testing the middle and back sections of flexible foam cushions. The hysteresis test is a viable option for car seat manufacturers as it benefits both the seat manufacturer and purchasing customer. As with IFD/ILD tests, this test ensures that manufacturers are not using too much foam during production as well as measures firmness and comfort for the customer.
Hysteresis tests are a form of compression testing similar to IFD/ILD, measuring the firmness and uniformity of car seat cushions. It measures the hysteresis energy loss of foam, providing the difference between loading and unloading energy. The goal is to ensure passenger comfort when loading the seat as well as unloading it. As a more technically challenging test, this option uses the same test machine as IFD/ILD but requires additional steps of computer analysis. The results provide the most comprehensive firmness information and accuracy available.
Bolster Testing
When foam is poured into molds to create rounded car seat cushions, small bubbles and imperfections can occur. Bolster testing is an important part of the car seat testing process as it checks for imperfections and firmness of the sides and arms of the seat. Some manufacturers use hand held scales for bolster testing, but our engineers recommend against a manual testing technique due to the fact that viscoelastic materials such as foam vary in firmness based on the rate of loading. Therefore a rate-controlled firmness testing machine is needed to ensure accurate rate control. Manual techniques allow excessive variability in the test results and will expose you to risk of poor product quality.
A customized two inch platen is also available with our bolster testing software to outfit your existing IFD or Hysteresis compression test machine. Our foam test software and fixtures cover a wide range of car seat testing standards including:
- GM6293M Polyurethane Foam For Automotive Seating Applications
- GMW15471 Molded Foam for Seating Applications
- PV3410 - PUR Flexible Foam; Testing Methods
- TL 526 53 – PUR Flexible Foam for Vehicle Seats
- WSS-M15P20 Requirements for Seat Foams
TestResources car cushion test equipment is capable of adhering to these select standards and more, including test standards from major automobile manufacturers including BMW, Volkswagen Group, Chrysler, GM, and Ford. Call today to speak directly with a test engineer and we will help configure the best testing plan and equipment for your car seat application.
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