Attached are a few photos of my current direction and experimentation with Mahor's extruder v3. I'm trying to overcome the following challenges with this new design:
Stability - the original design is a bit wobbly and flexible when mounted to the CR10, you can see in some of Maho's videos he has used aluminium to make the front and back plates, but as I don't have the tools to do this I wanted a 3D printed solution.
Dust and mess - if your active cooling is blowing air into the hopper and your printing with shredded wast plastic then you end up with bits of plastic getting blown everywhere. I wanted a different location for cooling (this is not a problem with pellets).
Prevent blockage - shredded wast plastic is very high friction and the pieces of it are very light so it dose not flow very well.
Make it easy to mount to my CR10 - now it mounts directly.
The design I have created also has some disadvantages too, its heavier, its much harder to print, it requires quite a lot of post processing and is much harder to assemble, so if your just printing with pellets and its stable enough for your use case then the original design would be easier to work with.
I printed the housing in Carbon-fibre PETG and the hopper in clear PETG. It was my first time using Carbon-fiber PETG but it printed very well and without problem, however it did take 26 hours on my FFCP! I will print more with this as it make super stiff, strong and light parts, better than anything I used before.
The stl's can be downloaded from here: https://www.thingiverse.com/thing:3032188
Recently I have been doing longer and larger prints which after an hour or so of printing often fail with the extruder getting stuck and the geared stepper motor skipping steps. I thought it that the nozzle was getting clogged, or that some of the PET bottle plastic had different melting temperatures to others. However it seams to be because the geared stepper is getting to hot which means its power output is not enough to tern the extrusion screw and this is happening even at very low speeds like 10mm/sec.
How I came to this was by letting the machine cool down after failing to print the heating up then nozzle like normal and trying to extrude some filament. When the stepper was cold it could push out the filament without any problem. I'm now waiting for a heat sink to arrive, then I will add a heat sink plus a fan to the stepper. Steppers can apparently run very hot over 120 degrees, but for me its getting hotter than that I think as so much power is needed to rotate the screw. Maybe a bigger stepper would be the way to go for a next upgrade.
Using the current design (V3), I'm having a big problem with the feed stock I'm using getting stuck as it falls down the tube. Sometimes it gets stuck in the tube it self, sometimes in the printed part that goes around the housing at the top of the auger.
I'm using ground up PET bottle plastic, the flakes are 3mm and smaller, however its still getting stuck. I will post updates if I find a fix to this problem. If anyone already has a good way to improve the flow of plastic to the auger please share.
I was making some progress, but then one of the drivers on my CR10s's board broke and as they are part of the board I need a new one. This will also give me the opportunity to use the DVR8825 recommended driver which is not on the stock CR10s board. I'm thinking to use this China clone board and drivers pack: https://item.taobao.com/item.htm?spm=2013.1.20141003.4.23692b62yv00sA&scm=1007.10011.70203.100200300000001&id=520116334260&pvid=f8295471-7659-4525-878f-6aa25a1f0257
Any advise would be welcome.