With marbling, coloured surfaces are obtained by an inhomogeneous mix of different materials.
The marbling effect is achieved by the use of different coloured materials, which are usually of the same type. Due to the inhomogeneous melt, variously coloured sections, which can be more or less intensive, appear on the part. If the viscosities of the melt are very similar, a faint marbling effect occurs. However if they differ significantly, the margins between the colours are clearly defined.
The structure of the colour effects is determined by the differences in the melt index of the materials, the percentage share of the materials, the cylinder temperature and the injection speed.
Die Struktur der Farbeffekte wird bestimmt durch die Unterschiede im Schmelzindex der Materialien, die prozentualen Anteile der Materialien, die Zylindertemperatur und die Einspritzgeschwindigkeit.

Instead of a plasticising screw, a plunger unit is used for marbling. Plasticising is achieved by pushing the material forward, step-by-step, in the heated plasticising cylinder. This is a recurring process in marbling, whenever material is injected into the mould.
A temperature profile is set within the cylinder, which extends from the newly fed solid material at the back through to the liquid melt at the front. The quantity of material used is refilled into the cylinder after every injection procedure by means of a dosage unit.

This technology is applied, for example, in the production of high-quality light switches and outlet covers for household use or to produce jewellery or buttons. Schmuck und Knöpfen eingesetzt.