Wilmington Machinery invests $2.5M in R&D lab | Plastics News

Oct 30, 2024

Novi, Mich. — Wilmington Machinery has invested about $2.5 million in its research and development lab to demonstrate low-pressure molding with foam, or gas-assist molding, particularly for use with high-pressure molds or incorporating recycled materials.

The R&D lab has a new Lumina 2400HE hydraulic press with 500 tons of clamping force, a 50-pound shot size and platen size of 70 by 80 inches to produce parts up to 70 by 60 inches.

During the low-pressure injection molding process, an inert gas is introduced into the melted polymer to reduce the density and weight of the finished products, which have cellular cores surrounded by rigid skins.

The Wilmington lab is used to show the advantages of low-pressure molding with gas to foam the plastic, such as lightweighting; spotlight the company's technology advances; do gas-assist mold trials and pilot production runs of 500 to 1,000 pieces; and trial new materials, additives, fillers and compounds.

"We've been in business for more than 50 years and are continually improving the technology," Jim Boos, vice president of sales and marketing, said at the Injection Molding and Design Expo, held Sept. 20-21 in Novi.

Boos said he fielded a lot of questions about what low-pressure structural foam molding is, and his answers surprised many.

"I don't think a lot of industry knows you can potentially run a high-pressure mold in a low-pressure machine," Boos said. "You can bring that mold to Wilmington, and we can trial it."

Low-pressure machines typically run multiple molds at the same time, which is an attractive capability.

"If you can put four high-pressure molds in a single low-pressure machine and make four parts at the same time, that saves you from running four different machines," Boos said, pointing to savings of time, energy, capacity, floor space and labor.

Founded in 1972 to build structural foam injection molding machinery for furniture, Wilmington expanded into machinery for polypropylene handles for the brush industry then pallets and other products.

Wilmington's low-pressure structural foam machines have large platens — from 54 by 54 inches to 108 by 186 inches — and multiple nozzles capable of being arranged to fill several molds simultaneously.

The company also builds rotary blow molding machinery and systems.

With low-pressure injection molding with gas, plastics processors can reduce part weights by 10-30 percent; use nitrogen, carbon dioxide or chemical blowing agents; mold large parts with low clamp force; lower energy costs; produce complex parts without sink marks; and produce parts that can be sawn, screwed, nailed or stapled like wood.

The new Lumina 2400HE lets Wilmington engineers demonstrate how best to produce high-quality products. Processors can conduct experiments and trial new materials, additives, fillers, compounds and molds — even high-pressure molds.

High-pressure molds with a cross section over 3/16th of an inch (0.19 inches) can be run with nitrogen gas or chemical foaming agents in a low-pressure machine with multiple molds mounted to the large platens.

The parts don't have to be the same size, weight or shape. "Imagine the savings when running four molds simultaneously with one structural foam machine," Boos said. "Plus, reducing the need for extra floor space, lowering labor costs with only one operator and trimming utility costs as well as performing less maintenance."

Wilmington engineers helped one company solve a problem by producing a flat polyethylene lid with overmolded rebar for the cover of a water meter. The cover is installed flush to the ground and needs to withstand weather, insects, lawn mower blades and more.

"By running a high-pressure mold in a low-pressure machine with gas, we were able to make a flat lid to satisfy their customer," Boos said of the meter cover, which has an opening to place a radio transponder so utility workers can pick up readings without leaving their vehicles. "Structural foam is an excellent application for that."

Production-ready systems are available to make large parts with virgin or recycled plastics.

"The raw material can be 100 percent recycled material. Our process is very forgiving and can use the lowest-cost recycled materials," Boos said. "Low-pressure structural foam is, I think, by far the best process for recycled materials."

In addition to mold trials and low production runs, the lab has a pallet mold and offers pallet samples. Or processors can bring their own pallet mold.

The portable platforms are in high demand from the logistics, food, beverage, automotive and pharmaceutical markets, and plastic pallets are gaining popularity for their durable and sanitary nonporous surfaces.

"Only a small percent of the pallets in the world are plastic," Boos said. "Most are wood, which carries contaminants and bugs and absorbs spills. Plastic doesn't do that."

Plastic pallets can cost more than wooden ones, and that has been a hurdle to faster market acceptance, Boos said, but it doesn't have to be for some processors.

"A lot of companies produce scrap like polyethylene and polypropylene and at the same time buy pallets. Why not take that scrap, install a low-pressure injection molding machine, turn the scrap into a plastic pallet and eliminate the purchase of pallets?" Boos asked. "It's an excellent alternative to wood and a good way to use the scrap you're generating at your business."

Do you have an opinion about this story? Do you have some thoughts you'd like to share with our readers? Plastics News would love to hear from you. Email your letter to Editor at [email protected]

Please enter a valid email address.

Please enter your email address.

Please verify captcha.

Please select at least one newsletter to subscribe.

Find more newsletters at plasticsnews.com/newsletters.You can unsubscribe at any time through links in these emails. For more information, see our Privacy Policy.