Injection compression moulding

Want to produce thick-walled and optical components with low stress and no sink marks? That's where we come in! With detailed process knowledge and high-quality machine technology.

Benefits at a glance


What's special about injection compression moulding? The change in cavity volume during the injection or holding pressure phase. For the production of precise free-form surfaces, for example.


The mould only closes completely or a compression stamp only moves forward when there is melt in the cavity. This means that a uniform pressure is exerted on the corresponding surface.


With injection compression moulding, you can achieve larger flow path to wall thickness ratios and reduce shrinkage and distortion effects. For high dimensional accuracy and part quality.


What is particularly important for optical parts is that injection compression moulding reduces internal stresses in the part as well as birefringence effects.

Injection compression moulding: LED attachment lens example


Light testing

Polarised light can be used to check the stress distribution in the moulded part. For example, stress birefringence can be seen at the injection point of an injection moulded part.

Sample components

LED attachment lens

ARBURG is involved in the OptiLight research project: Injection-moulded precise free-form surfaces purposefully direct the light of innovative hybrid optics into a rectangular illumination profile.

Belt pulley

With thermosets, injection-compression moulding can be used to increase part strength and avoid sink marks. For the belt pulley, the coining gap in the mould is 7 mm.

Spectacle lens

In ophthalmic lenses for spectacles, the thickness of the part can be adjusted by means of the compression path. The coining time for a 10 mm thick lens is 90 seconds.

Turnkey projects

Automated production cells from a single source

Want to increase added value, optimise the injection moulding process, automate further, and integrate innovatively? Then we are your partner as a primary contractor. As we already are for many leading companies worldwide.

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Technical articles

Process Optimization

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