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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.

The information below is intended as a general overview, settings may vary depending on the specific grade selected. Please CONTACT US for detailed processing information


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 Depending on the grade of material, the lowest temperature of material in runner, during unloaded parts of cycle should be 170 - 240°C
Cylinder temperature

190 - 245°C (260°C may be necessary for large parts)

Mould temperature 15 - 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 Depending on the grade of material, the lowest temperature of material in runner, during unloaded parts of cycle should be around 170 - 200°C
Cylinder temperature 170 - 200°C, should not exceed 220°C
Mould temperature 15 - 60°C
Injection velocity SBS compounds should preferably be injected at moderate injection velocities


Comprehensive information about TPE processing is available in PDF format;

TPE Processing Guide

TPE Problem Solving