Riverdale Global, American liquid colour specialists, will be at NPE2018 with a colour metering control system for injection moulding.

Its system ensures colour uniformity and saves costs by dosing colourant during the injection phase, when conventional colour and additive metering systems are inactive.

Riverdale’s technology will be adapted for solids-metering systems from its affiliate, Maguire Products.

Liquid Colour metering from Riverdale Global

During the injection moulding cycle, about 75 per cent of virgin resin enters the screw during the screw recovery phase and 25 per cent during injection. Because conventional metering systems add colour only during recovery, insufficient mixing can occur, which is particularly problematic when shot size approaches screw capacity or when the product is translucent.

Paul Maguire, president of Riverdale Global, said: “100 per cent Injection Coloring technology saves colour costs and ensures product uniformity in many moulding applications and is particularly valuable when shot size is close to barrel capacity. With conventional colour metering systems, there simply is not enough mixing time in the barrel to colour the 25 per cent of barrel content to which colourant has not been added. Over-colouring can usually fix the problem, but not always, and especially not with translucent parts. For these you need to use either a larger machine or an upstream pre-mixer.”

Riverdale Global - Booth S22023 at NPE2018.