Two plastic components are injected alternately into the cavities during interval injection moulding. In contrast to two-component injection moulding, colour effects are created by the two plastics flowing into each other in the case of interval injection moulding technology. With this procedure there are no clear colour separations - it is intended that the two colours blend together.

Numerous colour effects in the moulded part can be reproduced during manufacturing as often as desired by the application of interval injection moulding. ALLROUNDER two-component injection moulding machines are used, equipped with a special interval unit.

The two injection units are coupled together by means of a special interval unit, inside which the mixing nozzle is located. The interval unit is fastened to the fixed mounting platen of the machine and is thus located in front of the mould. The two materials are injected into the mould through this special nozzle, which results in the typical colour effect. The coloration is influenced by the cycle sequence, the design of the moulded part, the position of the sprue and the flow properties of the injection moulding materials.

The decisive influencing para-meters are simultaneous or alternating injection, the control of the interval cycle rates and modifying the speed of the injection. A special interval program in the ALLROUNDER control unit ensures the correct cycle sequence and the control of the plastic melts.