Injection Moulding
In the injection moulding process TPE pellets are fed into the machine through a hopper and then into a heated barrel. The heat from the barrel turns the material into a liquid resin which is then injected into a closed mould under high pressure. After allowing the molten polymer to cool, the finished part can be removed from the mould.
Injection moulding is a high-volume, high tooling cost process, the advanced properties of our TPE compounds deliver short cycle times allowing parts to be produced at a rapid rate.
Settings
| Equipment: |
Conventional injection moulding machine |
Compression set:
|
At least 2:1. Special screws with short sections and higher compression ratios (3:1 to 4:1) may be good at low screw speeds.
|
| Shrinkage: |
Between 1.0% and 2.5% depending on the grade, type of application and location of the gate. |
| Mould surface: |
Produced by EDM or shot blasted is recommended. |
|
Ejection:
|
Ejector plates are generally recommended for soft grades. If ejector pins are used, they should be as large as possible and act on sections of the part that are stiffest. |
| Gates: |
Diaphragm gate, fan gate, submarine gate, multiple-pinpoint gate
|
| Venting: |
A vent groove depth of 0.01 to 0.02 mm is generally sufficient |
SEBS based materials
| Runner temperature: |
Lowest temperature of material in runner, during unloaded parts of cycle should be around 185°C
|
| Cylinder temperature: |
190 - 245°C (260°C may be necessary for large parts) |
| Mould temperature: |
30 - 60°C |
Injection velocity:
|
Due to the strong viscosity/shear rate relationship, a high injection velocity is desirable for SEBS based materials.
|
SBS based materials
| Runner temperature: |
Lowest temperature of material in runner, during unloaded parts of cycle should be around 175°C |
| Cylinder temperature: |
150 - 205°C, should not exceed 220°C |
| Mould temperature: |
20 - 40°C |
| Injection velocity: |
SBS compounds should preferably be injected at moderate injection velocities. |
Comprehensive information about our Dryflex S injection moulding grades, processing and our Dryflex XL TPV injection moulding guidelines are available in PDF format;
Dryflex S series - Injection Moulding
Dryflex XL series - TPV
Processing Guide
Problem Solving
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