Selecting the Right Raw Material for Injection and Extrusion
Every plastic process has its own raw material requirements. We cover the key criteria that determine the correct granule selection for injection and extrusion.
Even the same polymer type behaves differently in different processes. Injection molding and extrusion are two fundamental methods of plastics production, and each expects different properties from the raw material. Choosing the right granule is decisive for efficiency and product quality.
Raw Material for Injection Molding
The injection process relies on the melt being injected into the mold at high speed. Therefore, granules with high flowability (high MFI) are preferred so that complex geometries and thin walls fill completely. Dimensional stability and a low shrinkage rate become important in precision parts.
Raw Material for Extrusion
In extrusion, the melt is pushed through a die to form a continuous profile. Since melt strength is critical here, low-MFI, high-viscosity grades are preferred. In the production of pipes, profiles, sheets and film, the melt must hold its shape.
Decisive Factors in Selection
- MFI value: Flowability balance according to the process.
- Thermal stability: Resistance to degradation during long residence times.
- Additive requirement: Need for lubricant, stabilizer or filler.
- Mechanical targets: Balance of impact resistance, rigidity and flexibility.
A raw material unsuited to your process lengthens cycle times and increases scrap rates. At SNC Plastik, we offer granule grades optimized for your injection and extrusion lines, together with technical consultancy.