Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:2344053.
Disclaimers
- I am yet to test it out myself.
- This is highly experimental. Try at your own risks
As of the time of writing, It serves as an alignment tool to (re)assemble your Kossel Mini corner brackets/frames. Cheap Chinese Kossel Mini kits usually come with 2020 extrusions with poor cut tolerances resulting in slightly different length for the sides of the triangles. Resulting non-equilateral triangles if you try to force them together with the corner brackets without a jig or guide. Ultimately, affecting the accuracy of your effector's movements.
The idea is by using a 3d printed "jig" in order to make sure all of the triangles are equilateral and equal in size and length so that your effector could print/travel under minimum distortions as the result of angled towers and twisted frames.
How to print
- Measure the length from A to B (as shown in the picture)
- Repeat the measurements 6~9 times on all sides of the triangles (including the top and bottom)
- Find the largest value of all the measurements, call it K
- Scale the length (z) of the 2020 extrusion with T minus 6mm.
- print the 2020 extrusion or order a custom length 2020 extrusion from your local shop or Aliexpress
- Print the extrusion mounting bracket, make sure the tolerances are good enough to fit the 2020 extrusion.
How to use
- You will need to disassemble most of the frame, leaving the triangles intact.
- Install the mount with M4 t-slot or square nut and an M4x8mm screw.
- Loosen up the screws that are holding the corner brackets in place so that you have room for adjustment.
- now install the 2020 extrusion onto the mounting bracket, since the triangle frame is already loosened up, you should be able to adjust the A-B distance, now make sure the A-B distance equals to K
- once you did that, tighten up the corner bracket that the 2020 extrusion is pointing.
- repeat the steps above on all 3 sides of the triangle.
- repeat the steps above on all the triangles (usually just top and bottom)
- now you should be a properly aligned frame!
P/S: it should work with just about any delta that shares the same Kossel corner brackets. You just have to make sure the mounting bracket is centred and scale the Z axis of printed 2020 "extrusion" according to the largest distance you measured for your frame.