Kossel Mini build : Part 0 – a brief explanation of intent and also sources where I got the parts
Kossel Mini build : Part 1 – assembled the top triangle frame, as it seemed like the simpler of the 4 main components
Kossel Mini build : Part 2 – assembled the diagonal rods by leveraging parts used on the bottom triangle base
Kossel Mini build : Part 3 – while building the effector, encountered some fitting issues on both the plastic and nylon screws. A combination of dremel and tap and die were used to make things fit. Also finished the auto level probe.
Kossel Mini build : Part 4 – the diagonal rods were installed to the effector, and the J-Head hotend was also attached to the effector. Also finished the bottom(base) of the Kossel Mini.
The rails finally arrived, and after a minor QA issue(that the vendor was quickly able to remedy) I can continue with the Kossel Mini build. This build session took longer than anticipated – it happened over several nights from Friday to Sunday, and I finished write up on Monday evening. And now, back to the build.
I used the following parts
- 6 x endstops
- 6 x M3x8mm screws
- 6 x M3 nuts
- 3 x micro switches
- 6 x M2.5x8mm screws
I also needed:
- 6 x wires to solder to the switches
- shrink tubing to seal the soldered ends
- female headers to solder to the ends of the wires(so I can connect them to the RAMPS board)
The endstop assembly is pretty straight forward, each piece gets 1 x M3x8mm screw and a M3 nut as shown below
Three endstops will also require 1 x micro switches to be added via 2 x M2.5x8mm screws.
I soldered wires to 3 micro switches.
Micro switches are screwed onto the endstops via 2 x M2.58mm screws.
The rails need some preparation as well:
- 3 x 400mm rails
- 48 x M3x8mm screws
- 48 x M3 nuts
The rails have 16 holes and each hole gets a M3x8mm screw and a M3 nut.
These rails, 1 end stop, and 1 end stop with microswitch goes on each of the three 600mm extrusions.
Each extrusion also got an endstop and an endstop with a microswitch.
I measured out 50mm on a caliper and using it’s depth gauge, spaced out the endstop with the microswitch so the three rails would all have the endstops with microswitch, the rails, and the endstops spaced out all the same. This is my attempt at trying to avoid endstop calibration headaches.
I also snaked the stepper motor wires through the base, so it can be inserted into the vertical extrusion.
I found that if the wires are tightly twisted and then inserted into the side channel of the extrusion, the wire bundle will unravel and hold itself in place.
As for the belts, the kit that I purchased included a single 4 meter length belt. What I did was measure out and cut three even belts.
Again, this is so that calibration will be easier later on.
First, the carriages are attached to the rail platforms.
I made sure all three had exactly the same number of teeths – again, to ensure that all three vertical rods would be the same.
The same thing for bottom belt. There was a LOT of leftover belt from the bottom, but it did not interfere with the stepper motor on the bottom base.
Finally, I am using a RAMPS 1.4 shield and a Arduino Mega 2560 that I had been using from my previous printer as the controller.
Using whatever screws I had leftover from my kit and spare parts drawer, I was able to mount the RAMPS board on the top of the Kossel Mini.
Note that I am using 4 nylon washers(2 on each screw) that is quite hard to see. The parts are assembled like below:
Oh boy, the machine is nearly complete! But this is where I’ll stop for today.