The automotive industry relies on the firmness of their seat cushions to provide safety, durability and comfort for customers. In order to create quality seat cushions, car seat manufacturers have special foam firmness test requirements. The firmness of a polyurethane cushion is measured by performing a test called indentation load deflection, or ILD.
What is an IFD/ILD Test?
Also called an IFD test, this test measures 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. This test is typically an accelerated or simplified version of the latex foam industry standard, ASTM D3574.
Car seat manufacturers focus on two important factors when researching test equipment for their IFD/ILD testing: efficiency and accuracy. This test requires several repeated tests to the middle and back of the car seat, therefore efficiency is an important factor when choosing a test machine. TestResources IFD/ILD software features a reduced test time duration from 15 minutes to as short as 1 minute for quicker test results.
Accuracy is another essential component for car seat foam testing. Due to the high amount of repeated tests, even slight variations between test articles is evident. TestResources 370 Series ILD Foam Testers deliver accurate ILD firmness readings for foam and foam product applications. Another way to increase accuracy of test results is to perform hysteresis tests.
Hysteresis Testing
Hysteresis tests are another option for testing the middle and back sections of flexible foam cushions. 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. As a more technically challenging test, this option uses the same 370 Series test machine as IFD/ILD but requires extra budgeting for computer analysis. The results provide the best possible accuracy in test data.
IFD/ILD & Hysteresis Test Machines
TestResources offers multiple load frames that are modular in nature to be matched with different sample sizes easily. Each machine includes a load frame, actuator, load cell, position sensor, controller, IDF/ILD or Hysteresis test software, PC, indentor and baseplate matched to sample sizes.
370 Series Automotive Foam IFD mechanical frame configuration is engineered to enable all tests to be performed sequentially. The design makes it possible to take an individual seat and to test the wings, seat back, bottom and head rest in a single sequence of setups.
IFD/ILD Software
Our Indentation Load Deflection or ILD test machines feature ASTM compatible test software and test reports. The IFD test software is configured so that the test definition can be pre-selected by engineering or management personnel, and test operation is placed in the hands of the test operator. Digital data is captured and stored as test reports for quality recording purposes. The data can be transferred electronically to a secure server using existing corporate internet tools. The data includes raw indentation and force data as well as firmness calculations.
The 370 Series Indentation Load Deflection or ILD test machines are also fitted with special IFD platens and test fixtures, available to match different sample contact modes, including flat and hemispherical versions. For help configuring the best test machine and testing plan for your foam application, give one of our engineers a call today.