Portable, Accurate, Open Source 3D Printer
More information, parts, kits, assembled printers available at printerkitten.com
Printer Kitten Design Story
3/31/16 - Patrick Woolfenden
The first printer I built was Sublime’s Tantillus. The Tantillus’ small size and print quality are what drew me to it. The Ultimaker Style X and Y axes motion system were fascinating. For me, the Tantillus turned out to be a great first printer. It wasn’t the easiest to put together and I had to source all of the parts myself, but in the end it didn’t disappoint delivering exceptional print quality.
Inspired by the Tantillus and the other T-Slot Tantillus and Ultimaker style printers, such as Brad Hill’s T-Slot Tantillus, Tim Rastall’s Ingentus, and Eric Lien’s HurcuLien, I set off to design my own version. This printer had a 200mm X 200mm print area and was roughly the same size as the Ultimaker. It used a 20mm extrusion frame, and toothed belts where the Tantillus had used high tension fishing line. After meeting Martin Bondėus at the 2015 MidWest RepRap Festival I decided to try the Bondtech extruder. It proved to be much more consistent and reliable than the Tantillus extruders I was used to. The printer worked well and produced great prints, but had its own set of issues. It remains unreleased, as I don’t think it’s ready for other people to try to build. It work well and had many unique design features that found their way to the Kitten.
The next printer I designed was the Kitten. Reflecting back to Midwest RepRap Festivals I had attended, I remembered how the Tantillus intrigued people because of its small compact design. I decided to make my next printer compact and portable.
I enjoyed the challenge of trying to package all of the printer components into the smallest and spatially efficient layout I could. In order to make the printer very compact the Kitten was first laid out with all of the X and Y-axes, print head, and frame purchased parts positioned in space. I iterated, trying different motor sizes and positions, rod diameters, bearing sizes, etc., keeping in mind that I would be designing printed parts to hold parts together. I decided on a 15mm T-slot extrusion [extruder or extrusion?], Nema 14, and E3D lite hot end. After feeling happy about the compact packaging layout, I began designing the printed part for the printhead. Once that was roughly designed I moved onto the rest of the X and Y-axes, making slight tweaks to the component layout as necessary. A clever way to tension the belts is key to the Kitten’s compact design. To fit in the small space available, hall effect switches are used for end stops. At this point I was confident that the frame foot print would be a 200mm square with a 100mm square print area. The X and Y-axes and printhead were the most challenging parts of the printer, with the goal of as small of a foot print as possible.
For the Z-axis I opted for a simple cantilevered bed. 10mm rods and flanged linear bearings were used because they were the largest that could fit without increasing the size of the printer. Three oversized parts make the Kitten’s small bed very sturdy. A Nema 14 stepper motor with an integrated lead screw is used to move the bed. In order to keep it simple and stiff I decided to make the bed out of 2 metal plates. A silicone heated pad is used for bed heating. Leveling the bed is easy with 3 adjustment nuts.
The Ultimachine mini-rambo was a great fit for the Kitten’s control electronics because of its ease of use, low profile, and small foot print. I stuck with the Bondtech V2 extruder for the Kitten. While the Kitten uses Nema 14 motors for the X, Y, and Z-axes, it still uses the standard Nema 17 for the extruder. I designed a pivoting spool holder that can be folded away to retain the Kitten’s small size for travel. Since the first Kitten, the printed parts have gone through many iterations. All of the printed parts of the Kitten have been designed so that printing without support material is possible. One part has a break way support modeled directly into the STL file.
During the couple of months leading up to the 2016 Midwest RepRap Festival I built 2 more Kittens and made a kit for a friend, who built his own and provided me feedback. My friend Matt Skorina and I traveled to the Midwest RepRap Festival with 3 Kittens, reading to debut them to the 3D printing community.