Monster Kossel Mixed Frame

UPDATE: I'm marking the Monster Kossel v1 as done.

I've printed a few hundred hours on it and proved it works as a printer reliably and with good precision. However the v2 is coming soon, and adds acrylic panels to make the printer enclosed, with the goal of fitting a HEPA and charcoal filter with a fan in aspiration on the top section, keeping the chamber in negative pressure. This is to placate my better half's concerns about health risks associated with lots of printing in a multi-purpose space.

These are the frame parts I modified from the original Kossel frame to work with the 2040 tower extrusions for a larger size.

The carriages are designed to snugly fit on the 20mm side when using original v-roller wheels from openbuilds.

The motor frames could use an additional tweak to allow for easier mounting of the NEMA 17 steppers in place, but that will be an upcoming edit. I increased the height of the bottom frame bits to get a more rigid feel between the tower and bottom frame.

UPDATE : just to make life easier for everyone, I want to point out that I'm still assembling this one. I've built a collection with all the parts I've printed that will go into this printer here: http://www.thingiverse.com/goeland86/collections/monster-kossel - if you need additional bits you can use those as a reference instead of having to go hunting on your own for what works best. I posted the files before I was really ready because of a request on the Replicape slack team and found a whole lot of folks liked this design already... Thanks!

UPDATE : 29.06.17

I realized while assembling my Monster that the carriages I originally remixed wouldn't work when trying to put on the belts. I'm including a thicker version to enable you to use the original Kossel Mini carriages. I've also tightened the axles a bit to get a bit more of a snug fit on the 20x40 extrusion, as mine were loose with the genuine OpenBuilds V-Rollers.

IT PRINTS : 10.07.17

Finally! After a long time, I managed to pull of my first prints off the bed of the Monster Kossel yesterday. I'm using a Replicape board at the moment, with FSR bed leveling.

Some of you will have noticed that the steppers' lower screw holes can't be reached by a wrench... Sorry about that, but holding the motors in place with only two screws is working just fine for now, and the lever effect when the belts are tensioned mean the system is self-stabilizing as is, but I do plan on fixing those corners when I have a chance to. Oh that and also make some better cable management for those interested in mounting electronics on the top frame like I am. Pictures will come soon, I just want to make sure I clean up the mess of moving parts a bit... Final print volume looks to be around 320mm diameter by 440mm vertically, which is just what the doctor ordered.

UPDATE 30-sept-2017

So I still had some annoying wobble on the frame despite the use of the 20x40 extrusions for the towers. It was limiting the speed at which I could move and print. I fixed this by getting about 6.5 meters of 2mm steel wire to build cross bracing. Stick an M5x5mm screw on the top and bottom outside face of each OpenBuild extrusion and make one loop on the wire. Hook it to one screw and just go around the frame, up and down as required, and you should eventually come back to your starting point. Tension it gently by hand instead of going at it hard - too much tension will warp the frame out of square. Leave a little bit of margin upwards on the top screws, so you can tension by pulling the screws up, instead of re-sizing the cable. Works like a charm!

Print Settings

Printer Brand:

RepRap

Printer:

RepRap Kossel

Rafts:

No

Supports:

No

Resolution:

0.2

Infill:

25-30%

Notes:

Select infill to taste based on the strength needed. I found that 30% was more than sufficient to handle the requirements for the 1m tall extrusions.

How I Designed This

I imported the files in Blender, imported the Openbeam 1515 and OpenBuilds 2040 profiles to use a boolean operation around them. I then slightly scaled the extrusion size to give enough tolerance to print such that the extrusions will fit.

Category: 3D Printer Parts