GMNA GM7400M PDF

This standard provides a system for specifying significant properties of commonly used plastics, including unpigmented and pigmented, unfilled and filled products. It is intended to apply to parts (not resins) primarily as used in the automotive and related industries. It is also intended to be used either as the sole descriptor of a material or within the body of a specification covering the common standard characteristics required wherein additional specialized requirements are detailed.

It is based on the principle that plastics should be described, insofar as is possible, in terms of specific performance characteristics desired in the molded part and that an infinite number of such descriptions can be formulated by the use of one or more standard statements (based on standard tests) each designating a quality level of a property or characteristics. Thus, users of plastic parts can, by selecting different combinations of performance characteristics, specify different combinations of properties desired in various parts.

To permit line call-out of the descriptions mentioned, the system includes a symbol for the general type of plastic resin to be used and a letter number symbol for each quality level of each property or characteristics.

Example: An automotive interior part might be specified as follows:

GM7400M ABS (DSB83, FM2200, RE20, SGE895, TSB46)

NOTE: While this cell type format provides the means for close characterization and specification of each property and combination of properties for a broad range of materials, it is subject to possible misapplications since impossible property combinations can be coded if the user is not familiar with available commercial materials.