| Abbreviations/Acronyms |
ASTM, American Society for Testing and Materials International
C, Degrees Celsius
CFD, Compression Force Deflection
CFR, Code of Federal Regulations
CNC, Computer Numerically Controlled
ECN, Engineering Change Number
FMVSS, Federal Motor Vehicle Safety Standard
h, hour
HR, High Resilience
IFD, Indentation Force Deflection
ISO, International Standards Organization
LTF, Load Test Fixture
N/m, Newton per meter
m, meter
max, maximum
min, minimum
mm, millimeter
N, Newton
OEM, Original Equipment Manufacturer
PPAP, Production Part Approval Process
RH, Relative Humidity
SAE. Society of Automotive Engineers
UTM, Universal Testing Machine |
| Definitions |
| A-Surface: The surface of the pad that is in contact with the trim cover. |
| B-Surface: The non-exposed surface, bottom of a molded foam pad. |
| Cells: The individual cavities in the skeletal structure of the foam formed by the nucleation and growth of bubbles within the reacting liquid. |
| Cellular Material: A material composed of a multitude of interconnecting cells. |
| CFD (Compression Force Deflection): A measure of the load bearing ability of a foam. It is the pressure exerted against a flat compression foot larger than the specimen to be tested. The value can be expressed at 25%, 40%, 50%, and/or 65% compression (ASTM D3574). Note: previously called "CLD” (Compression Load Deflection). |
| CFD Change: The change in hardness of a foam specimen, expressed as a percentage of the original force measured at 50% compression, after the specimen is subjected to accelerated aging. |
| Compression Set: A permanent partial loss of initial height of a flexible polyurethane foam sample after compression due to a bending or collapse of the cellular framework within the foam sample. A high value of compression set will cause a flexible polyurethane foam cushion to quickly lose its original appearance with use, leaving its surface depressed or "hollowed out". Compression set is measured in the lab by compressing a foam sample 50% of its thickness (or down to 50% of its original thickness) and holding it at elevated temperature and/or humidity. Compression set is most commonly expressed as a percentage of original thickness. Other deflections, times, and temperatures can be used. |
| Constant Force Pounding: A fatigue test that measures (1) the loss of force support at 40% IFD (2) a loss in thickness, and (3) structural break down as assessed by visual inspection. |
| Core: The internal portion of foam, free of any skin. |
| Core Density: The density of the foam sampled without skin, glue lines or compressed sections at or near the center of the final foamed shap |
| Cure: A term referring to the process whereby the urethane chemical reaction approaches completion. At 100% completion, a foam should have 100% of the physical properties attainable with that particular formulation. |
| Density: A measurement of the mass per unit volume. It is measured and expressed in kilograms per cubic meter (kg/m3). |
| Dual Density or Firmness Pad: A foam pad that is molded with one density or firmness foam in the main body of the pad and higher density or firmness foam in the bolsters. |
| Fatigue: A softening or loss of firmness/thickness. Fatigue can be measured in the laboratory by repeatedly compressing a foam sample and measuring the change in IFD and thickness. |
| HR (High Resilience): A variety of polyurethane foam produced using a blend of polymer or graft polyols. High resilience foam has a less uniform (more random) cell structure different from conventional products. The different cell structure helps add support, comfort, and resiliency or bounce. High resilience foams have a high support factor and greater surface resilience than conventional foams and are defined in ASTM D3453. |
| Hysteresis Loss: This test measures foam resiliency by determining energy loss during loading and unloading of the sample. Low hysteresis loss equates to higher resiliency foam. |
| IFD (Indentation Force Deflection): A measure of the load bearing capacity of flexible polyurethane foam. IFD is generally measured as the force (in Newtons) required to compress a 324 square cm circular indentor foot into a part or block sample, to a stated percentage of the sample's initial height. Common IFD values are generated at 25, 50, and 65 percent of initial height. Note: Previously called “ILD” (Indentation Load Deflection). |
| Molded Foam: A cellular foam product having the shape of the mold cavity in which it was produced. |
| Open Cell Structure: A permeable structure in flexible foam in which there is no barrier between cells, and gases or liquids can pass through the foam. Most cell walls have been ruptured to varying extent. |
| Polyurethane Foam: A flexible cellular product produced by the interaction of active hydrogen compounds, water, and isocyantes. |
| Recycled Content. The portion of a material's or product's weight that is composed of materials that have been recovered from or otherwise diverted from the waste stream either during the manufacturing process [pre-consumer/post-industrial] or after consumer use [post consumer]. |
| Renewable Content Foam: Polyurethane seating pads that are manufactured with a foam chemistry where a portion of the petroleum based component is displaced by natural oil-based derivatives. |
| Resilience: An indicator of the elasticity or "springiness" of foam. It is measured by dropping a steel ball onto the foam sample/cushion and measuring how high the ball rebounds. |
| Skin: The smooth surface layer of a molded foam product, formed when the reacting chemicals contact the mold surfaces. |
| Split Bolster: This is a dual firmness or density bolster. The bolster is split by a narrow trench, which places firmer or higher density foam on the outer edge of the bolster and softer or lower density foam in the inner portion of the bolster. |
| Support Factor: The ratio of the 65% IFD to the 25% IFD reading. |
| Tear Resistance: A measure of the force required to initiate/continue a tear in foam. |
| Vapor Staining: The discoloration of a control vinyl sample from the volatiles released from foam. |
| Wet Aging: An accelerated aging method that requires the foam to be placed in an environmental chamber for a predetermined amount of time at elevated temperature and humidity levels. |
