Equivalent-grade searches are useful for generating candidates, but material equivalence is application-specific.
The substitution basis should be the requirements controlling part function, processing and approval rather than a line-by-line match of published datasheet values.
Define the functions the material performs
Document the mechanical, thermal, chemical, electrical, dimensional, appearance and other functions the material provides in the finished part and production process.
- Part function
- Loads and failure modes
- Service temperature
- Chemical and environmental exposure
- Dimensional requirements
- Processing requirements
Separate acceptance criteria from screening data
Properties such as tensile strength, flexural modulus, impact and melt flow can help narrow the candidate set, but not every published property is an application acceptance criterion.
Identify which values control the decision, which support screening and which require direct evaluation in the intended application.
Account for formulation differences
Base resin, reinforcement, fillers, impact modifiers, stabilizers, flame-retardant systems, colorants and processing aids can affect finished-part performance and production behavior.
Materials within the same polymer family can therefore require different processing conditions or produce different aging, dimensional and surface behavior.
Include the production process
Compare flow, drying requirements, thermal history, shrinkage, warpage and cycle behavior where they affect the intended molding, extrusion or conversion process.
A candidate that meets property targets but cannot run within an acceptable production window is not an effective substitute.
Close important gaps with evidence
Use targeted testing and representative production trials where published information does not resolve an application-critical difference.
The required evidence should be proportional to the technical risk and the approval requirements of the application.
Technical references
