Rapidia is a Canadian manufacturer of metal 3D printing systems. The company was formed in 2015 and spent the last 5 years developing an advanced, entry-level metal 3D printing system. Rapidia was the first company to use a simple 2-step process (print and sinter), the competition taking years to catch up. They are the first company to use a water-based chemical free process offering many environmental and metallurgical advantages. It was the first company to use a novel vacuum furnace design using innovative materials, allowing rapid sintering capabilities in a low-cost furnace. At this stage the product is in production.

Rapidia was founded by Dan Gelbart, a well-known Canadian technology entrepreneur, who was the founder or co-founder of several successful Canadian technology companies: Creo, Kardium, MDI, Cymbolics, and Ikomed. Dan holds 144 US patents and has received numerous awards.

Interview with Skyler Des Roches, Engineer Lead at Rapidia.

Easy Engineering: Which are the fields of activity where you are operating?

Skyler Des Roches: In order to deliver Rapidia’s additive manufacturing solutions, our team works on hardware development, manufacturing, materials science, and automation.

We’ve developed a two-step system for 3D printing metal. First, parts are printed by extruding a water-based bound-metal paste. This is especially powerful for parts with complex internal geometry, including closed internal spaces, as there is no need for de-powdering. Then, the green part that comes off the printer – which at this stage is like dried clay made of metal particles – and gets sintered in our vacuum furnace. Thanks to our unique water-based feedstock, the parts require no separate debinding stage. This approach allows users a quick iteration cycle; you can start a print one day and have a metal part the next. 

Rapidia manufactures these machines (the printer and sintering furnace) at our Canadian headquarters, employing lean manufacturing principles. For the manufacturing team, this means they’re always assessing the process and thinking about how to make improvements to build a high-quality, reliable product.

Then, we have a team working on developing new feedstock materials for the printer. We’ve given ourselves a big engineering challenge by starting with a water-based paste with really the very minimum of binding additives. Other extrusion-based metal 3D printing uses feedstock that’s basically metal held in a plastic filament. Printing filament is much more mature technology, but the tradeoff is that the quantity of polymer binders in the filament requires either a lengthy chemical debinding process, or a very slow thermal debind. With a water-based feedstock we’re able to use the absolute minimum of binders – about 1/10th as much as used in other 3D printing technologies or metal injection molding – and cut a day or more off the print-to-part time. It also means that Rapidia’s system achieves excellent material properties through thick parts, with solid infill.

We continue to work on software to improve the simplicity of using our technology. The ultimate goal, I think for everyone working on additive manufacturing technology, is to have a machine that works something like the replicator machine in Star Trek: scan a part, or load a 3D model, and get a functional part a short time later. Behind the scenes, there are a lot of knobs to twist, and a lot of knowledge required to get a good result, so have automated as much as possible. It’s obviously not at the level of a “replicator” yet but someone with FDM 3D printing experience will find the experience with our printer familiar, and anyone can achieve good results quickly. Using our 3D printer is certainly much easier and requires much less knowledge than using a CNC mill, for example.

E.E: Which are the most significant projects from 2022?

S.D.R: Feedstock development continues to be an important and one of our most challenging engineering efforts. There are many advantages to a water-based feedstock, however, developing paste that prints nicely, and complimentary sintering cycles to achieve material properties equivalent to wrought metal, is a complex, multivariable project. Powder metallurgy is a relatively young field, and sintering expertise is generally guarded by industry, rather than available in publications. Our team has conducted lengthy studies to achieve the desired results. 

So far, we have two fully qualified stainless steel materials available with our printer – 316L and 17-4PH – which offer as-wrought material properties for parts of any thickness. We are close to having a stable formulation for Inconel 625 and H13 tool steel.

E.E: What are the usual challenges you encounter? 

S.D.R: With many of the engineering projects behind Rapidia’s product design, there are a large number of variables that impact results. For example, the surface finish of a printed part is impacted by several variables within the feedstock formula, many areas of the printer hardware, as well as software. In a start-up, or really in any design role, it’s important to move quickly. So, there’s always the temptation to make changes without fully understanding their complete effect.

E.E: How did you overcome the challenges?

S.D.R: To deal with the complexity of developing new technology, we’re fostering a company culture of seeking understanding before seeking solutions. No matter which design challenge we encounter, the framework, or approach, we use to tackle that challenge as a team has a big effect on the outcome. Realizing this has really empowered everyone working at Rapidia to commit to continuous self-development, so that we’re always learning as much and as quickly as possible.

E.E: Why did the clients choose your products / solutions?

S.D.R: Rapidia’s metal 3D printing system is very affordable and user-friendly compared to other metal AM systems. Our waterbased feedstock completely avoids the health and safety concerns typically associated with powder metallurgy. The safety of the system also supports the other big appeal of the system: speed. Anytime people are working with loose metal powders, they should be donning full-body PPE. Depowdering parts made from loose powder, or changing materials, requires a lot of careful labor, and equipment to do safely.

By using water-based paste, all the time spent taking safety precautions is saved. Using the Rapidia system is not much different from using a normal plastic 3D printer. Our customers value this lack of barriers for using the technology. This gives it great appeal for rapid prototyping, where the iteration cycle for a metal part is unrivaled. As a designer myself, I’ll choose to 3D print parts even with relatively easily machinable part geometry to leverage the automation inherent in the system. The actual cutting time for the same part on a CNC mill might be lower, but it requires a lot more operator input to set-up tools, fixturing, and material prep. With the 3D printer, it takes a few minutes to convert a 3D model to the printer g-code, maybe 3 minutes to start a print, and then it builds a part without supervision. However long later, when the print is done, starting a sintering run takes 1 minute. So, I can have finished metal part the next day, and in that time, I’ve only had to pay attention to the process for a few minutes total. The more complex the geometry of the part, the bigger this advantage becomes.

Compared to other metal extrusion systems, Rapidia’s water-based approach saves a huge amount of time with either chemical or thermal debinding. Water evaporates out of the part during printing, whereas other systems suspend metal powder in polymers which must be removed in a separate step.

Another appeal of the water-based approach is that it allows parts to be assembled from multiple prints. It’s easy to brush water onto the connecting surfaces, which will rehydrate the green part and allow you to bond multiple prints together. Once sintered, this yields a seamless, full-strength connection.