In February, MISUMI USA hosted a contest on Reddit for 3D Printer BOMs that used MISUMI components. We’d like to congratulate our second place winner, Brad Hopper, on his design of a deltabot 3D printer called the Hot Bot.
According to Brad, “The BOM is a refined version of the original HotBot (also using Misumi parts), the building of which is detailed in the Google Deltabot forum. Original HotBot is strong enough to mount a spindle and mill aluminum!” Check out the buildlog, watch a video of it milling aluminum and download the BOM to create your own!
This new HotBot is sleeker and easier to work with than the original and has several advantages over cartesians and the classic Rostock/Kossel and current Mini Kossel designs by Johann Rocholl.
Simpler, Cheaper, Scaleable: Because of their high degree of symmetry, delta printers have a smaller number of unique parts and lower overall part count than typical cartesian printers. This makes them cheaper and faster/easier to build. Deltas have a stationary bed, which also lowers cost and raises stability. Finally, the simplicity of the design allows for easy scaling – just get longer or shorter members and connect them the same way!
More Rigid: Among deltas, use of the excellent and inexpensive Misumi 60 degree extrusions as the primary vertical members allows for a more rigid triangular frame than is possible using printed parts.
Space Efficient: HotBot is only ~6cm wider than the original large (360mm sides) Kossel, but the printable area is ~200% larger! (~12″ diameter) Using the OpenSCAD design you can customize it and make a smaller (or larger!) one if you prefer.
Less Warping: Fully enclosed chambers give much better results for high shrink printed plastics like ABS/polycarbonate and larger PLA parts. Most printers (especially deltas) are hard to enclose. With the HotBot, it is trivial.
Modular Enclosure: I’ve tricked out this BOM with triple sliding polycarbonate doors but you could easily put thin plywood or craft board in the rear/side extrusions and tape or screw additional boards to the front for easy access. Pennies for a controlled temp chamber!
Modular Motion: This BOM has a long linear rail in each of the narrow sides, but you could swap those for rods and linear bearings, or substitute a 20 x 40mm extrusion rotated 90 degrees (even moar rigid!) and use V-wheel carriages. Small enclosure slits along the center extrusion covered by a brush would even allow the moving parts to be 100% outside of the enclosure!
Precise Assembly –> Easier Calibration: The biggest knock against deltas is perceived calibration complexity. But experience has proven that most calibration problems stem from an inaccurate frame build. The “Truth Stick” in the BOM is a precision cut (+/- 0.2mm) gauge block that ensures each of the opposite extrusion pairs is equidistant from its partner and square to the uprights. Simply assemble all parts by “feel”, insert the truth stick, and tighten for a perfect fit, then move to the next side.