• 2015
  • Sep
  • 9

MINI KOSSEL - building a better carriage

Since xmas I am an owner of the 2014 Makergeek Mini Kossel Kit (http://www.makergeeks.com/mikofudiypae.html).

The kit is great - it came almost complete with solid parts for the frame, extrusions, enough nuts and bolts as well as linear rails, and a glass print surface. Belts, RAMPS, Arduino Mega, Power Supply, etc.

But the kit came incomplete, mine was missing a fan and a themistor. Living in the bay area pieces from Jameco where easier to order than trying to get the missing parts from Joshua at Makergeeks (Who was very helpful with advise during the assembly phase).

The worst part however where the 3D printed parts for the printer.
Especially the carriages that attach to the linear rails were rather badly produced. The parts were printed in a hurry, probably too hot and the infill was insufficient. This became clear during assembly. Due to the construction of the kossel the carriage is constantly under pressure.

carriageoriginalsmall.png

So as one of my first projects after printing a bed holder from thingiverse I started working on a replacement carriage and looked at a number of existing options before designing my own part. The design goals were easily defined:

  • Mount on existing linear rail
  • Provide maximal freedom for the traxx mounted carbon arms (I created my own since the makergeek arms did come apart during assembly)
  • Design for maximal stability of the carriage - especially for stable mounting of the belt holder
  • Ensure lasting pressure does not deform the belt holder
  • Design the carriage to not require zip-ties to fix the belt to the carriage
  • Help easy calibration of the printer by providing a calibration screw

The following part was the result of my openscad work:

carriagecustomsmall.png

As you can see the piece holds the belt in place by looping it back on itself. Therefore making the additional zip-tie optional. The opening for 4 screws in the back M3×10mm (from mrmetric) provide additional stability to the carriage.

The CC0 openscad file is attached here - and available on thingiverse as STL and openscad file.

I printed mine in 0.2mm layer height PLA on the kossel with support created with kisslicer, with 75% infill (I believe they would have been sufficiently stable at 50%). They have been used for over 2 months now.

Please let me know about any further improvement ideas you might have. I am planning to create a new effector next, before looking at magnet or all ball/spring mount options.

  • 2015
  • Aug
  • 8

3D Printing Toolbox

* Calipers