Introduction
Melt flow index is useful for screening thermoplastic grades, but the number is meaningful only together with the polymer, test temperature, applied load and test method. A similar MFI does not by itself prove that two materials are interchangeable.
Material Properties
- Confirm that temperature, load and test method are equivalent before comparing values.
- Review density, impact, stiffness, additives and other documented properties required by the finished product.
- Treat a missing or differently tested MFI as non-comparable until the supplier provides current documentation.
Applications
- Shortlisting injection-molding grades for a defined tool and part geometry
- Reviewing film or extrusion grades against line and product requirements
- Evaluating a proposed alternative to a currently approved resin grade
Processing Methods
- Send the current grade, equipment, process and finished-product acceptance criteria with the inquiry.
- Use MFI to narrow candidates, then review the full TDS and relevant application data.
- Run a controlled production trial and test the finished part or film before commercial approval.
Advantages
- Prevents misleading number-only comparisons
- Improves the quality of supplier quotations
- Connects flow behavior to process and product validation
ENGINEERING SUPPORT