Project: Micro Kossel

Micro Kossel Prototype as originally built

After taking my mini kossel to a couple of local events and finding it awkward to transport without two people and a car, I decided to research what options existed for a smaller delta-type 3D printer. Finding nothing that I'd consider rigid or durable enough for unshielded transport, and wanting to explore how small a Kossel-style delta could be built, I started Project: Micro Kossel.

Micro Kossel with demonstration safety shields

Project Goals:

• Rigid frame allowing for unshielded transport
• Lightweight for easy carrying
• Test viability of 3D printed frame for small printers
• Useful build volume (10 cm diameter cylinder, 7.5 cm height with current effector)
• High reliability

For the 3D printed parts I used a mashup of the Ultibots MKVS and the Griffon 3D delta, along with some parts from Thingiverse. Actually printing the parts took about 75 hours with my mini kossel, spread over the course of a month. When choosing electronics, I decided to use the venerable RAMPs 1.4 control boards to keep things simple and easy to setup. Firmware is the April 2016 master edition of Rich Cattell's Marlin fork for delta 3d printers, calibrated with the Escher 3D Delta Calibration Wizard. Assembly is mostly the same as a standard mini kossel (see this instructable for detailed assembly) with some minor changes, mainly the use of M5 bolts for all the frame fastenings, and some M4 or 8-32 threaded rod to link the v-slot sections into their final lengths.

Micro Kossel ready to print

I've had the prototype operational since April 23, 2016 and so far it's fulfilled all of my project goals splendidly. The 3D printed frame provides excellent rigidity while keeping weight low, indeed the heaviest parts in the printer are the 48mm NEMA 17 stepper motors, which has the effect of keeping the printer very stable when printing. Print quality is excellent with only minor issues due to a mild software bug in the display drivers that i've since corrected.

Micro Kossel as currently configured

If you want to build your own Micro Kossel, you'll need an updated copy of the Arduino SDK, Pronterface, and Slic3er to run the printer, along with access to a 3D printer with a 18 cm tall build volume for constructing the printed v-slot. If you have any problems or issues during assembly, feel free to post a comment.

Micro Kossel Files
  -Includes Bill of Materials, working firmware, and stls for the printed parts.

Acknowledgments:
Ultibots MKVS
Griffin 3D delta printer
Dasaki Ramps 1.4 Enclosure
Case for the Full Graphic Controller
Kossel E3D effectors
2020 V-slot reference
Rich Cattell's Marlin fork