Technology Spotlight – Gravimetric Feeders


In this edition of the Catalyst technology spotlight, we are talking about gravimetric feeders and how are they utilized at Catalyst.

Gravimetric feeders are devices that are utilized in line with injection molding equipment to disperse colorant or additive consistently during the injection molding process. All feeders are based on a volumetric feeding, but with the gravimetric type feeders, a weight system is added to control the discharge rate of the product.

Catalyst utilizes equipment such as the Novatec MGF Gravimetric Feeder to ensure consistent addition of masterbatch colorants and additives to injection molded components. These feeders eliminate waste and inconsistencies that are caused by manual mixing processes.

Each of the feeders include four modes of operation and are extremely easy to set-up for any particular molding project. The system only requires our team to enter the LDR (let down ratio) necessary and the shot size (in weight) for the part being molded. From there, the feeder adjusts automatically based on our screw settings on the molding press. The system also includes automatic re-calibration which adjusts feed rates within +/- 0.2% of the set LDR.

Data collection is made easy with the integrated microprocessor controls. The controls allow processors and operators, at any time, to capture necessary information on current set-up for future use and learnings via networking or physical USB connections on the unit. The feeders also help eliminate downtime in between color change overs. It is as easy as switching out the color hopper and adjusting the LDR setting for the next color run.

“The gravimetric feeders help us maintain color consistency at start-up, during a short sampling and throughout a release run of molded components,” VP of Operations, Ian Papineau, states. “Without these in place, we can see problematic issues during the molding process; such as discoloration, poor color mixing (milky streaking, similar to splay) and inconsistent colors from part to part.”

Catalyst utilizes two feeder systems across four presses in the injection molding department. Each of the presses have a rapid change fixture system that allows our team to quickly move one or both of the feeders to different press locations based on the scheduled molding needs for particular project.