Earlier this month we reported on a company called Mini Metal Maker, which had launched their second Indiegogo campaign to raise additional funding for their unique and affordable 3D printer. After raising close to $35,000 back in December of 2013, the company wanted to expand their production even further via this new crowdfunding campaign.
Their 3D printer is different from others currently on the market, in that it allows for printing using a special metal-based clay. This clay can be fired in a kiln at 1550˚F (600˚C-900˚C), leaving printed products which are made up entirely of fused metal particles.
To show the potential that this unique 3D printer has, company co-founder David Hartkop decided to use his $1500 machine to print out a functional pair of metal scissors.
“The idea to print scissors came from the realization that we could print not only ornamental objects but actual tools,” Hartkop tells 3DPrint.com. “We are using a specially blended bronze metal clay produced for the Mini Metal Maker by Metal Adventures. The clay we used, BRONZclay3D, is chemically very similar to the ancient ‘bronze age’ bronze used to make coins, statues and swords.”
To create this incredible pair of scissors, Hartkop began modeling them using LightWave to create a prototype. He elected to go with a completely symmetrical design so that he could simply print the same object twice (both blades) and then screw them together. Once he had his design complete, he used Slic3r to break it down into individual printable layers.
“We essentially adapted a number of filament extrusion settings to apply to nozzle and clay flow settings in our machine,” Hartkop tells us. “The Mini Metal Maker draws with wet but stiff metal clay extruded from a syringe under 300+ psi of electromechanical force.”
He then 3D printed the scissors with a 0.25mm layer height in 15 layers. They took approximately 42 minutes to print using a 22-gauge extrusion nozzle which allows for a line width of around 0.28mm. In all, about 15 grams of metal clay was used in the process. Hartkop then allowed the clay scissors to dry overnight, prior to dusting them off. He decided not to sand them down, but rather leave the rigid 3D printed texture in place.
“Metal clay is [a] water soluble mixture of metal particles and an organic binder,” explains Hartkop. “It is easy to re work a surface by sanding or rubbing with a wet paint brush. Additionally, surfaces can be smoothed by painting with ‘slip’ or extremely wet clay. Cleanup is essentially the same as working with ceramics in the ‘greenware’ stage. It is a bit more flexible, though, and withstands drilling and handling without falling apart.”
In order to turn these clay scissors into a solid metal object, they were placed into an electric kiln that featured a slow ramp of just 250˚F per hour, and held in there at 1550˚F for two hours. Normally bronze objects are very ductile because they are generally allowed to cool very slowly after being fired. Hartkop wanted his scissors to be strong and hold a sharp edge though. After his scissors were fired, he elected to heat treat them with a blow torch and then quench them in water.
Just like with ceramics, metal clays also shrink up upon being fired. The scissors started out with a maximum dimension of 84mm when they were wet, shrunk down to 83.25mm when dried, and then down to 76.85mm after being fired in the kiln. After the firing of the scissors was complete, Hartkop proceeded to polish them with steel wool to bring out the metallic shine. He then sharpened the blades with an 80 grit sandpaper wheel before finishing the job with a jeweler’s file.
As seen in the video below, the scissors actually work quite well. Hartkop has tested them on some pieces of thread, a business card, a strip of corrugated cardboard, and more.
“These seem to work best with paper, though I would expect them to be fine with cloth if they were properly sharpened,” he tells us.
This is really quite some amazing progress within the 3D printing space. Just a few years ago, you would have been hard-pressed just to find a desktop 3D printer that could print in plastic. Now, thanks to the Mini Metal Maker, 3D printed metal objects can be created on a machine that will cost you just $1,500. Hartkop has proven that his printer isn’t only feasible for creating ornamental jewelry, but it has the ability to print out functional parts as well.
For those of you who can’t afford the $1,500 that this printer will cost you, you can purchase the DIY instructions and build files to build your own metal clay printer for just $25.00, also via the Indiegogo campaign.
What do you think of Hartkop’s unique creation? What other types of cool metal objects would you like to see him 3D print? Discuss in the Mini Metal Maker forum thread on 3DPB.com. Check out the video of the scissors being printed and put to use below, as well as some more photos.