New feedscrews equal better production for Swan

Screws are the backbone of the plastics industry, the method of melting and conveying plastic pallets into a mold or die.

But consider what is needed for screw replacements in extrusion — that's the subject of this month's Best Practices.

We turn to Pawcatuck, Conn., where Davis-Standard LLC partnered with garden hose manufacturer Swan Products LLC to install four new feedscrews on Swan's existing Davis-Standard extruders at one of its plants in Canada.

From order to installation, the project took about two and a half months.

Replacing old screws can dramatically boost productivity in a cost-effective manner.

"We were able to replace feedscrews on older machines and improve throughput by over 33 percent," said Jose Rossi, Swan Products' director of manufacturing for North America.

Rossi said Davis-Standard's lab facility at its headquarters "enabled us to prove design concepts alongside feedscrew engineers with hands-on experience. They were very thorough in their management and delivery."

The new high-throughput designs included one feedscrew with a screw diameter of 2.5 inches and three 4.5-inch screws. Swan officials made the trip to Pawcatuck because the hose maker needed capabilities to process both PVC and thermoplastic vulcanizate resins. During the trial, several designs were tested to determine the best options for outputs and stability specific to Swan's processing requirements.

Jason Baird, the senior process engineer at Davis-Standard who conducted Swan's trial, said that working with Rossi in the lab was essential to ensuring the designed outcome.

"We have analytical capabilities at the lab that enable us to see what's going inside the extruder as we test different feedscrews," Baird said. "When you improve output rates, you also need to confirm stability to achieve uniform product."

Swan supplies garden hoses to major big-box retailers, so quality and consistency are essential to the company, Baird said.

"We were able to verify both outputs and stability while also evaluating every aspect of performance from melt temperature to torque. This gave Swan the validation they needed to achieve immediate results," Baird said.

Atlanta-based Swan was one of the original manufacturers of watering hoses. The company was founded in 1927 as the Swan River Tire and Rubber Co.

Davis-Standard offers research and development, feedscrew replacement and rebuilding services. The company can design screws for any extruder brand and barrel. In addition to replacement screws, Davis-Standard offers barrel measurement services to ensure dimensional fit and best performance.