Thermoforming is a well-established plastic manufacturing process, yet it is often underestimated or misunderstood. Let’s explore this further and clarify its potential.

Dordan Collaborates with Nike on Thermoformed Shoe Box for SB Green Lobster Sneakers

Overview

• Thermoforming molds have become more complex, but their cost is only about one-quarter of injection molds.
• Advances in resins, sheet materials, and tooling have enabled thermoforming to expand into new applications.
• Dordan notes that there is increasing demand for domestic thermoformed plastic trays used for automated assembly.

The progress in materials, tooling, and technology continues to blur the lines between the most suitable processes for specific applications. Thermoforming is used to produce a wide range of products, from lightweight thin-wall packaging to thick, large panels and parts, serving industries such as automotive, agriculture, construction, medical, and aerospace.

Thermoforming Basics

Thermoforming involves the use of vacuum or pressure forming. In the vacuum forming process, a heated, flexible plastic sheet is drawn toward a mold shape by vacuum pressure. Formed Plastics Inc. explains, “Since pressure is applied only to one side of the plastic sheet, vacuum forming is typically used for parts with relatively simple designs and minimal texture.”

In contrast, pressure forming uses additional air pressure to push the plastic sheet into the mold, similar to blow molding. “The combined pressure on both sides of the sheet creates rich in-mold textures and allows for more complex geometries that vacuum forming cannot replicate,” they note. “If your part requires undercuts, tight radii, or sharp textures, pressure forming is often the better choice.”

The key advantages of thermoforming are its relatively low mold costs and ability to economically produce low-volume runs. Various materials are suitable for thermoforming, including ABS, acrylic, polycarbonate, Kydex (acrylic/PVC), and glycol-modified PET (PETG).

Rethinking Pressure Forming

Jay Waddell, an industry veteran with over 40 years of experience, founded Plastic Concepts & Innovations LLC in 1999. His consulting firm specializes in heavy-duty/trim sheet thermoforming. Waddell believes that pressure forming is often underrated, especially as it is entering markets traditionally dominated by injection molding. “Pressure forming offers a high degree of design flexibility,” he explains, noting that more companies are adopting pressure forming today compared to 15-20 years ago when only a few firms used it.

Heavy-duty thermoforming typically produces large parts, which can result in high shipping costs. As a result, companies serving these markets are often regional, with production runs ranging from 500 to 10,000 parts. This process competes with other manufacturing methods, such as rotational molding, structural foam, and metal forming.

Advancements in Thermoforming Molds

Thermoforming molds have also become more sophisticated. According to Waddell, mold costs are approximately 25% of the cost of injection molds, offering substantial economic benefits, especially for short-run jobs. “Medical plastics have become a major market for heavy-duty thermoforming,” he says, pointing to products like display housings and equipment panels. Manufacturers of recreational vehicles, boats, and agricultural and construction equipment prefer plastic panels over metal for their durability and light weight, contributing to significant advancements in heavy-duty thermoforming in these sectors.

Catalysis Additive Tooling, based in Westerville, Ohio, has made a significant breakthrough in thick-gauge mold manufacturing. The company, founded by Darrell Stafford and Rick Shibko, both former automotive engineers at Honda, developed proprietary materials allowing their 3D-printed mold parts to last thousands of cycles.

3D Printing: Friend or Foe?

Some heavy-duty thermoforming manufacturers view 3D printing with skepticism, fearing it could pose a threat to short-run orders. However, Waddell sees them as complementary technologies. “I believe heavy-duty thermoformers might want to invest in 3D printers to quickly prototype and make adjustments without having to go back and redo the entire process before full production,” he states.

Conor Carlin, Managing Director of Illig North America, a German machinery manufacturer, highlights how advancements in resin, sheet materials, and tooling have allowed thermoforming to meet the demand for ultra-lightweight parts with excellent barrier properties, providing both economic and environmental benefits. Carlin also notes that machine controls are becoming smarter, adapting to Industry 4.0 protocols.

Using rPET for Mixed Food Containers

Illig Maschinenbau GmbH & Co. KG has long been committed to the development of in-mold labeling thermoforming (IML-T) technology. Over the past two years, the company has worked with PFF Group to provide processing machinery that enables the production of a new food-grade packaging concept. This system, known as IMPAC-T, allows for the production of mixed-rPET (recycled PET) containers with card packaging in a single process.

PFF notes that using rPET offers opportunities for industries like dairy to transition from traditional polypropylene to circular economy packaging. Alston Dairy was the first to adopt the new IMPAC-T packaging for some of their yogurt products. PFF states that the inline manufacturing process consumes less energy and allows for higher levels of post-consumer recycled PET, achieving at least 50% recycled content, with potential for 100%. Card packaging uses up to 100% post-consumer waste, and all raw materials come from certified sustainable forestry products. Consumers can easily separate the plastic and card for further recycling, and these materials can be repurposed into new packaging. The IMPAC-T process reportedly reduces the carbon footprint by 46% compared to current assembly systems.

In-mold labeling for thermoforming (IML-T) is helping to enable the increased use of recycled PET vs. polypropylene in food container applications. Image courtesy of Illig Maschinenbau GmbH & Co. KG.

Benefits of Thermoforming for Thin-Wall Packaging

Sven Engelmann, a colleague of Carlin, points out that thermoforming is one of the best processes for achieving the thinnest wall thicknesses with high top-load strength for rigid thin-wall packaging. Engelmann, who is the Head of Packaging Technology at Illig Maschinenbau and a board member of the SPE European Thermoforming Division, adds:

• Thin wall thicknesses offer economic and environmental benefits.
• Fast processes result in higher output.
• Thermoforming mold costs are lower than injection molding.
• Most thermoforming applications only require a half-mold.

Steve Zamprelli, Vice President of Formed Plastics, a company based in Long Island, New York, with 77 years of history, elaborates on some of the advantages of thermoforming:

• It is typically a low-stress process that produces stronger parts with less concern about warping or distortion.
• Faster time-to-market, often with lower tooling costs, allows for easy adjustments during secondary processing.
• It can adjust material wall thickness and use multiple materials on the same mold.
• Manufacturers can produce larger parts with lower costs and smaller quantities.

Dordan: Reducing Tooling Costs and Increasing Productivity

Dordan Manufacturing Inc., a family-run business in Woodstock, Illinois, with 61 years of history, has established itself as a leader in thin-wall thermoforming for products like beverage cups, lids, and food containers. Chandler Slavin-Bond, Dordan’s Chief Marketing Officer, highlights the significant advantages of thermoforming over injection molding, particularly in mold cost reduction and increased production speed. “Compared to injection molding, thermoforming offers considerable savings in mold costs and improvements in productivity,” she says.

Additionally, she notes that twin-sheet thermoforming—a process that manufactures double- or multi-layer hollow plastic components—is gaining traction in the industrial blow molding market. “Like injection molding, twin-sheet thermoforming molds are cheaper than blow molding molds and can produce more complex shapes.”

Slavin-Bond further adds that macroeconomic factors are driving the growth of another product area: thermoformed plastic trays used in automated parts assembly. These rigid, thin-wall trays are used to precisely position components on assembly lines.

Dordan’s role in the thermoforming of the Nike SB Green Lobster sneaker box stands as a notable example of overcoming production constraints. Nike marketed the sneakers to skateboard enthusiasts, utilizing a lobster theme and designing a thermoformed box that resembled a fishing bag used on commercial boats. The box featured a 1/8-inch thick acrylic panel designed to look like a frozen lake.

The Growing Recognition of Thermoforming

Despite these innovations and advancements, Waddell points out that many people still do not fully understand the capabilities of thermoforming. “They don’t know about twin-sheet or pressure forming, or what can be achieved with these processes. They think everything has to be injection molded.” However, as industry leaders like Waddell, Carlin, Engelmann, and Slavin-Bond continue to promote thermoforming and its diverse capabilities, awareness of this technology is likely to grow.

For more examples of innovative thermoformed parts, check out PlasticsToday’s slideshow, showcasing some of the winners from the SPE Thermoforming Division’s biennial parts competition, held during the association’s meeting in Cleveland from October 23-26.

Original Source:

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