Since 1967, FD Plastics in Leominster, Mass., has been supplying processors with color concentrates made with single-screw extruders.

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Since 1967, FD Plastics in Leominster, Mass., has been supplying processors with color concentrates made with single-screw extruders. But earlier this year, the compounder (fdplastics.com) bought its first twin-screw production machines, furnished by Coperion Corp., Ramsey, N.J., for its plants in Massachusetts and Canada. As far as FD is concerned, there is no turning back now.

“We always believed that twins were ideal manufacturing machines, but we felt whatever production gains we’d achieve would be offset by their higher price,” says Darren Rosbury, president of the company and one of its owners. “But the business downturn of the past few years ago forced us to look at things differently. We looked at twins again as an opportunity to capture that 20% of the market in which we had not been able to participate.”

The twins—a model STS 50-mm in Leominster and a model STS 35-mm at a plant near Quebec opened up the blown film extrusion market for FD Plastics. “There are certain additive and concentrate packages required in blown film that simply cannot be produced on singles,” says Rosbury. “Now we can participate in this market.”

The move to twins, which required an investment by FD of about $350,000, also resulted in some unforeseen productivity gains. Its 4.5-in. singles, for example, took about 200 lb of material to purge between runs. The twins require 40 to 50 lb. The new twins also produce about 1800 to 2000 lb/hr—about twice what the singles generated, while consuming less energy, Rosbury notes. He adds that that color repeatability on the twins is better than with singles due to the increased dispersive mixing capabilities inherent in twin-screw compounding.

FD Plastics, which employs about 100 people in both locations and has annual sales of about $35 million, still runs 12 single-screw extruders, but plans on replacing at least one of them each year until they are a “twins-only” operation.