Mec’Nex – A Sub-$100 3D Printer Constructed of K’nex, Utilizes a Unique SLA Printing System

I hold a belief that 3D printing won’t fully catch on among at-home users until an affordable Stereolithography (SLA) based solution becomes available. SLA is definitely the future in my mind, as it has the ability to create more precise, detailed objects, while also causing less of a headache for users, when compared to Fused Deposition Modeling (FDM). It’s only a matter of time before someone comes up with an idea that can bring the price of this technology way down, to a price that most people would be willing to fork over for a 3D printer. That someone may just be a teenager, named Connor Coleman.

Coleman, a 17-year-old student at St. Paul’s School for Boys in Baltimore, Maryland, has come up with a design for a very unique SLA based 3D printer. It is unique in how it operates, but even more unique in how it is constructed. The Mec’Nex is a 3D Printer built out of K’nex and Meccano. Yes, that is correct. Those little construction toys that you probably played with as a kid, make up about 99% of this 3D printer.

“The K’nex frame is actually pretty bottom-heavy, and the truss construction ensures that the frame won’t deform or twist under the stresses from the motors,” Coleman told 3DPrint.com. “It actually is a pretty big frame. It sort of reminds me of the Makerbot Replicator Z18 – tall and rectangular. The pump nozzle is actually pretty large. I’m using it just because it is cheap and easily available. I’m sure that people will find upgrades as the project progresses.”

Currently Coleman is using a pump nozzle that is typically used to blow up basketballs, as his print nozzle. Keep in mind though, that Coleman’s 3D printer is not your typical 3D printer. Instead of using one of the traditional FDM or SLA based technologies, that we are all used to seeing, Coleman’s printer uses a combination of both.

“The difference with this printer as opposed to other SLA or SLS printers is that the resin flows through a nozzle and then is cured on the print bed by UV lights,” Coleman noted. “This approach is closer to an FDM (Fusion Deposition Modeling) printer in terms of software and hardware, which makes it easier and safer to use the machine. There isn’t a massive ‘vat’ of resin underneath a strong laser; instead the resin is only placed on the print bed as necessary.”

Coleman plans to find, adapt, and integrate some open source software built for FDM printers into his design. As for the nozzle, he is still looking for a better solution to the basketball pump nozzle because as we all know, these nozzles have a hole in the side of them which doesn’t exactly make them perfect for extruding a liquid resin. He will also be hacking apart some old 2D printers in order to recover some stepper motors for use in this machine.

“I aim to get the cost at least under $100, if not less than that,” he told us. “The more parts that are scavenged (especially the steppers), the lower the cost will be. I’m hoping to use readily available boards and software that has already been released for free to the public.”

The idea for this unique system of printing came when Coleman realized that he couldn’t build a platform that could be lowered into a resin vat with his K’nex and Meccano pieces. ” It was a lot easier to build a platform that was supported on both sides, and so I just took the whole resin placement system and inverted it,” he explained.

As for where he hopes to go with this idea, he tells us that he doesn’t know about future designs quite yet. He’d really like to keep the costs and ease of construction for this 3D printer as low as possible, so that makers can fully build, understand, and perform maintenance on their own machines. With the current design, Coleman estimate that it takes approximately one hour to build the outer frame, provided that the person doing the construction has all the right K’nex and Meccano pieces. “It’s pretty modular,” he told us. “Just five of the same levels, with slight modifications to accommodate various platforms for electronics or the rails for the axes. One of the difficulties will be running the belts to move the axes. The pulleys or whatever will be difficult to cram into the small spaces.”

Coleman is an IB candidate with a maxed-out schedule, as well as his Cross Country team’s captain, at St. Paul’s School for Boys. He also sings in the choir and is heavily involved in the STEM program as well as his school’s Kinetic Sculpture Team. “I love designing and creating things that move, just like hundreds of seventeen year-olds across America,” he explained. “I post projects to Instructables on occasion, and can be found often working with the Makerbot Replicator at school.”

Could this 3D printer change the way we think about this technology? Could a machine work with such a cheaply built design? Can Coleman’s unique SLA system produce results that will allow for us to forego expensive DLP projectors? Only time will tell, but it appears as though Coleman is onto something. Discuss in the Mec’Nex forum thread on 3DPB.com.