color is added throughout the cycle. Metering takes place at a faster
rate during injection because of the rapid screw movement during that
phase.
100% Injection Coloring technology renders unnecessary two
conventional solutions to inadequate mixing that pose added cost or
complications: the use of an upstream pre-mixer, or over-coloring to
compensate for insufficient mixing. Over-coloring adds raw material
cost for opaque parts and is generally not possible with translucent
parts.
A controller outfitted with 100% Injection Coloring technology is
available to liquid color users at no cost from Riverdale Global, which
supplies metering equipment as part of its service to customers. The
technology is also expected to be applicable in solids metering systems,
including Maguire’s MGF™ gravimetric feeder, but will require a new
controller that is currently in development.
“100% Injection Coloring technology saves color costs and ensures
product uniformity in many molding applications and is particularly
valuable when shot size is close to barrel capacity,” said Paul Maguire,
president of Riverdale Global. “With conventional color metering
systems, there simply is not enough mixing time in the barrel to color
the 25% of barrel content to which colorant has not been added. Over-
coloring 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.”
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TUBE NEWS EVENTS
April 2018
35