Description / Abstract:
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
resins (not parts) 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, whereas
additional specialized requirements are detailed.
Note: The resin supplier must provide a
certification statement meeting the resin requirements per the
callout of this standard. This certification must be loaded into
the GM Material Specification File (MATSPC).
Material Description.
The material description is based on the principle that plastics
should be described, insofar as is possible, in terms of specific
performance characteristics desired in the resin, 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 characteristic.
Users of plastic resin can, by selecting different combinations
of performance characteristics, specify different combinations of
properties desired in various resins.
Possible standard statements are defined in 8.1.
To permit line callout (e.g., designation on a part drawing, in
the math data or in a component specification) of the material
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 characteristic.
Example: The complete GMW15702 for an
automotive resin might be specified as follows: GMW15702- 120014
ABS (A2, A64, BJ730, D113, EM230/216/20, RT3.4, SS52). The
callout that is referenced on a part drawing in math data or in a
component specification would be GMW15702-120014 or GMW15702-120014
ABS
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.
To prevent this kind of misapplication for plastic resin, it is
required that the actual certification data relevant to the
specified call out be uploaded to GM MATSPC.
Symbols. The symbol of the plastic resin shall
be indicated per ISO 11469, ISO 1043, ISO 18064 and SAE J1344 on
the part drawing and/or in the math data file.
Typical Applications. Plastic resins used in
the automotive and related industries.