Structur3D advances technology with desktop injection molding platform

KITCHENER, Ontario—One of the downsides of developing a state-of-the-art 3D printing platform that can make customizable rubber parts is that, well, you're still making rubber parts.

So, Andrew Finkle asked himself the existential question made famous by the movie "Frozen:" "Do you want to build a snowman?"

"I do a lot of development and testing and I get bored of making just a gasket," said Finkle, the co-founder and chief technology officer of Structur3D, a Kitchener-based additive manufacturing company. "I try to think outside the box and ask, 'What are some interesting ideas?' "

That's why, if you scroll through Structur3D's online photos from its new Inj3ctor platform, you'll see a variety of gaskets, bellows, orthotics and … Disney's famous snowman, Olaf. In silicone form.

"That Olaf, I actually embedded an LED (light) in it with a battery, so you can actually click the Olaf through the silicone and it'll light up," he said.

Finkle isn't necessarily a "Frozen" fan—"I'm sure I will be someday," he said, chuckling—but, like Elsa, he does believe in using his powers to create new cool things out of challenging materials.

That's how the Inj3ctor was born. The new platform combines desktop injection with 3D printing to create new products with factory-grade rubber materials such as silicones and polyurethanes.

Using 3D-printed molds, the Inj3ctor uses curated material cartridges to mix and inject 2-component flexible materials into any customizable shape, enabling turnkey, small-batch manufacturing of rubber materials, Structur3D said.

This, the company said, means the models are viable for every step of manufacturing, from prototyping to production.

"This is kind of a creative tool and we're interested to see what people will use it for," Finkle said. "We really want to support the customers, so our two big focuses are introducing proper materials that meet customer needs and continue to develop on the firmware and software side to essentially build some programmatic processes for the device."

While 3D printing is well-suited for materials including plastics and metal, rubber has been trickier to solve. RTV (room-temperature vulcanizing) silicones were one option, but they took a long time to cure and weren't durable enough.

"To get the good silicones that are used in a lot of consumer products—and similar with polyurethanes—you need to use a two-component material," Finkle said. "It's required to mix the proper ratio of two different materials, and then there's a short window where these materials will cure."

With 3D printing alone, that window is too long because the material will slump or lose its tolerance in the printing process, Finkle said. But with injection molding, they can combine dispensing, mold mixing and then use a mold to hold the shape through a window "so the part that comes out the other end fits the tolerances that you intended at the beginning," Finkle said.

Inj3ctor users design a mold using computer software, then 3D print the part with standard, durable or dissolvable plastic. After choosing from thousands of liquid rubber materials—users can customize it based on durability, flexibility and cure times—the Inj3ctor fills the mold and creates the product.

"That was kind of the 'Aha!' moment we had," he said. "We said, 'Let's take a step back from directly 3D printing silicone. We know 3D printing works very well for plastic and metal now. Let's use that in combination with the rubber to build a stack of technology that would give us this part, at a reduced cost, that would give us a quick turnaround time similar to additive manufacturing."

The platform bundle includes the Inj3ctor and an Ultimaker S5 3D printer, along with additional accessories and support materials. The first batch started shipping in the last quarter of 2020 to industry 4.0 manufacturers.

Many early adopters have been companies that manufacture products with a short run—maybe 1,000 to 2,000 a year—since the Inj3ctor allows them to do continuous improvement. Companies also like the ability to, say, make a custom gasket for a tool.

But manufacturers aren't the only customers. Structur3D also has seen a good response from the medical community, who want to build medical devices or reproducable biological organs for surgeons to practice on.

"We've seen that rubber has a lot of opportunity that has a human touch point," Finkle said. "Cushioning in a vehicle or a medical device that's in contact with your skin … things like that are accelerating quite quickly in the rubber area.

"There are a lot of startups that want to prototype this and build this, as well as large companies that want to innovate from within. This helps them to fill that gap."