Allied Plastics has been thermoforming large plastic parts since its first days in business 25 years ago. The question is: Just how large?

“Our largest thermoforming machine can form a full sheet that is 8.5’ x 14’ with a 60-inch depth of draw,” says Jon Larson, OEM sales manager at Allied Plastics.

Yeah, that’s pretty big — and it’s pretty unique. Allied Plastics’ large-dimension thermoforming machine happens to be a twin-sheet machine, and it happens to be one of the largest in the industry.

But it isn’t just about shear size. Twin-sheet thermoforming offers some benefits of its own.

“With single-sheet thermoforming, you have a single mold,” Larson explains. “You heat up a single sheet of plastic to pliability, then press it against a mold by vacuuming out the air to produce your formed part. With twin-sheet thermoforming, you have two molds. You form a single sheet on the bottom mold, but then you also have a second sheet that forms on a top mold. Those two sheets are then fused together in the forming process.”

Sounds interesting, but why does it matter?

“Twin-sheet thermoforming opens up a range of design parameters,” Larson says. With a single-sheet product, for instance, a male feature on one side will have a void on the other. With a twin-sheet product, the opposite side can have its own unique geometry. “You can have a lot of structure with a twin-sheet part because two sheets are bonded together at various points throughout the part,” Larson points out.

Another benefit of large-dimension twin-sheet forming is that you can combine multiple components into a single part with no connections or seams.

Big products require big ideas

Larson points to finished products like kayaks, pontoon hulls, tractor roofs and auto body panels as common examples of where large-dimension twin-sheet thermoforming provides a distinct advantage. Allied Plastics has also manufactured a long list of unique large-dimension products like stormwater management chambers, extended truck fenders, and customer pallets. If a customer expresses a need, the team at Allied Plastics comes up with an idea for getting it done.

Speaking of ideas, the company’s unique IDEA Center brings key personnel together from engineering, tooling and quality control to deliver creative solutions more efficiently than ever.

“If we have a large part that might seem a little bit tricky, the project goes through our IDEA Center,” Larson says. “The cross-functional IDEA Center team collaborates on how to best engineer the part to make it manufacturable and up to the quality standard outlined by our customer.”

Unique equipment, unmatched expertise

In addition to the massive twin-sheet thermoforming machine, the production floor at Allied Plastics also features three robotic trim cells. Those robots take care of the perimeter trim on a large plastic part, along with details like mounting holes.

According to Larson, having the right large-dimension manufacturing equipment is only half the battle. You also need the right people. Allied Plastics has both.

“When you’re doing large-dimension thermoforming, it’s not always easy to maintain dimension and consistent material thickness,” Larson points out. “Plastic is not as stable as other materials. If you’re working with polyethylene, a 12-foot part can expand or contract over an inch in a 50-60 degree temperature change. With the expertise we have, we can work with the customer to design for that kind of expansion and contraction. Maybe polyethylene will move too much for what our customer is trying to achieve. We can then help recommend an alternative material such as a TPO to make a more stable plastic that makes the finished part more successful.”

Allied Plastics’ large-part forming operation can handle a variety of plastics including HDPE, HMWPE, TPO, high-gloss and low-gloss ABS, styrene, and others.

“We have people with the right experience and expertise,” Larson continues. “We recently celebrated our company’s 25th anniversary. Many of our key employees have been with the company since the very beginning, meaning many decades of experience with large-part forming. That makes a huge difference in our quality and consistency.”

Contact Us Today to discuss how Allied Plastics can help you with your large-dimensional project.