Duo Form, a leader in thermoforming for wide-ranging industries, has worked with 3D Systems to integrate additive manufacturing into its process. As a result, the company has become more agile by printing production molds, tools, and samples for thermoforming and vacuum forming with a Titan 1270 Pellet system, drastically decreasing costs and shortening lead times.

Thermoforming, a widely used manufacturing process for shaping thermoplastic sheets into various products, has a rich history that traces back to the early 20th century.

The process gained significant attention during World War II when there was a need for lightweight and cost-effective manufacturing techniques. In the 1940s, advancements in plastics technology and the introduction of vacuum forming revolutionized the field. Vacuum forming involved heating a thermoplastic sheet until it became pliable and then applying vacuum pressure to mold it to a desired shape.

Throughout the following decades, thermoforming continued to evolve and expand its applications. The 1950s saw the development of pressure forming, which allowed for the creation of more intricate and detailed parts. In the 1960s, advances in material science and machinery made thermoforming more efficient and precise.

In the 1970s and 1980s, the introduction of computer-aided design (CAD) and computer-aided manufacturing (CAM) systems further enhanced the thermoforming process, enabling complex part designs and precise mold making.

Since then, thermoforming has become integral to many industries, including automotive, packaging, aerospace, medical, and consumer goods. It offers numerous advantages, such as low tooling costs, rapid production, design flexibility, and the ability to create large parts.

Today, thermoforming continues to evolve with the integration of automation, robotics, advanced materials, and 3D printing. Manufacturers are constantly exploring innovative techniques and materials to improve efficiency, sustainability, and the quality of thermoformed products.

Like many companies, Duo Form, a Michigan-based thermoformer, works to innovate its manufacturing process, shorten lead times, and reduce costs while maintaining mold quality and durability. To stay competitive, the company must also innovate quickly with design iteration and produce full-scale prototypes to avoid delays in the approval and production process.

Duo Form turned to 3D Systems’ expertise and now creates thermoforming molds using polymer pellet extrusion on its Titan 3D printer, replacing traditional CNC methods to make ceramic or metal molds. Large-format pellet-extrusion additive manufacturing uses readily available thermoplastic pellets common to other extrusion manufacturing, such as injection molding. However, it costs up to 10 times less than traditional fused deposition modeling (FDM) filaments. 3D Systems’ pellet extrusion systems also enable high-throughput printing, with print speeds up to 10 times faster than filament systems.

“In many cases, 3D printing molds can reduce or eliminate the need for CNC machining, especially if the gauge of the formed part is thicker than 1/8 in. and the appearance of small layer lines from the printed mold will not impact the use of the backside cavity of the final formed part. The layer lines do not bleed through the outer part surface with proper print parameters,” said Clay Guillory, director of Titan at 3D Systems.

3D Systems and Duo Form identified a grade of glass-filled polycarbonate pellets ideal for thermoform molds. The pellets are affordable, easily procured, and proven to withstand the thermoforming process as a durable and dimensionally accurate material.

For example, CNC finishes tend to be smooth, whereas large-nozzle 3D prints often exhibit layer lines and “stair-stepping” at fillets and curves. Such artifacts have not been evident on Duo Form’s formed sheets, even sheets as thin as .090 gauge. It’s also possible to vary layer thickness in the software to smooth out curves with finer layers and speed up the print with thicker layers elsewhere.

“Engineers may opt to use a smaller nozzle and finer layer height for pellet extrusion when 3D printing a mold to minimize the effect of layer lines,” said Guillory. “3D printing can be used in conjunction with CNC machining, such as printing a near-net shape fast with larger nozzles and then machining just the outer layers to finish the part and achieve smooth, accurate surface finishes. Depending on the final part geometry, CNC machining can also be done in situ by printing a section, machining that section, and then continuing that process until the full part is complete on the printer. This requires a system that has pellet extrusion and CNC milling tool heads on the same machine.”

Duo Form also leverages 3D Systems’ printing experience to achieve optimal printing parameters to create molds with the right porosity to function as vacuum passages. This unique ability of additively manufactured molds eliminates the need for special tools to properly form cavities into the thermoformed component, further reducing time and labor costs for producing molds.

For example, molds made from wood, ceramic, or aluminum require holes to be drilled through them for the vacuum to pull the sheet tight against the mold. With extrusion 3D printing, it’s easy to create molds with inherent porosity right off the printer.

As for durability, 3D-printed molds hold up against traditional methods.

“We have several 3D printed tools that have well over 1,000 pulls on them with little sign of wear. One of them is a 36 x 30 in. RV shower pan forming .150-gauge ABS. Another one is a 9-cavity 8-in. square component forming plumbing bezels,” said Dave Rheinheimer, product development manager at DuoForm.

Incorporating AM goes beyond the mold-making process for Duo Form. The company also utilizes its Titan 3D printer to quickly print sample parts of final products to present to customers ahead of making the tool. Directly printing parts for design approval before the mold-making process has opened the door for faster design iteration and shorter lead times.

“Thus far, we have only produced new molds and prototype parts,” said Rheinheimer. “One of our first prototypes was a faucet stand-off bezel that incorporates a bypass valve. We discussed the part with our customer on a Monday. On Tuesday, they sent us the CAD for the part and asked if there was any way they could have a part by Thursday. We got them a 3D-printed part by the middle of the day on Wednesday.”

Since implementing AM as part of its manufacturing process, Duo Form says the company has won more business and now closes deals faster thanks to the speed and agility of pellet-extrusion 3D printing.

“3D printing enables thermoforming companies to digitally change designs and iterate products quickly and cost-effectively without having to go through the traditionally longer process of creating tools and holding down fixtures,” said Guillory. “The ability to print a prototype and production tool all from the first print with minimal labor, lead time, or waste enables manufacturers to keep up with customers’ potentially changing demands.”

Rheinheimer also sees another value that AM brings to manufacturers for storing molds, especially for products that are out of production but may need to be formed in the future for spare parts. With AM, a digital inventory can eliminate the need to store legacy molds, enabling companies to print a new mold when needed.

“The physical storage of thermoform tools is also something that can be taken into consideration,” said Guillory. “The ease, fast speed, and low cost of 3D-printed thermoform tooling allow using a tool and discarding it after a production run is completed. This also enables a company to scan old tools in warehouses, keeping a digital library with the ability to just print the tools later on. This frees up space for additional production without the additional cost of real estate.”

Ultimately, Duo Form’s adoption of large-format pellet extrusion 3D printing exemplifies how AM and traditional methods can work together to achieve optimal manufacturing speed, cost management, and quality part production.

“We are also exploring how we can recycle printed molds and patterns. Extrusion-printed parts can often be recycled by grinding them up and re-pelletizing the material for 3D printing or other molding methods. The viability of the process depends on the specific material and the intended use of the recycled material,” said Rheinheimer.

Duo Form
duoformplastics.com

3D Systems
3dsystems.com