Hello again,
I finally was able to update the project and bring it to a state which I now consider finished (although no printer is really ever "finished" 
) I am very happy with the end result and has proven to be a reliable machine.
Some KEEVO printed parts:
I hope you like it. If you see any apparent improvements that can be made to the design, please let me know! The project can also be found on thingiverse: https://www.thingiverse.com/thing:4129443
Cheers!
Hello again,
I just wanted to share with you the last build I made, which of course uses Duet
(KEEVO = Cube in Greek)
(yeah the cables need some management)
It is also posted on Thingiverse -> https://www.thingiverse.com/thing:4129443
Any feedback is welcome of course!
Also, regarding the 3 leadscrews (which are only really mounted on the bottom), do you think that the forces from the Z belt will bend the leadscrews in the long run. I don't really see any bending though. It can be seen more clearly in this video which was the previous version (an hbot without duet and other stuff, but z axis is the same) -> https://www.youtube.com/watch?v=K0pcGKAQ4eA
Cheers
@matt3o I hope you solve the problem you are having!
The bowden tube is ~680 with the current position of the extruder.
@matt3o Thanks I guess Haha. Your printer design looks really great!
Hello again,
I finally was able to update the project and bring it to a state which I now consider finished (although no printer is really ever "finished" ) I am very happy with the end result and has proven to be a reliable machine.
Some KEEVO printed parts:
I hope you like it. If you see any apparent improvements that can be made to the design, please let me know! The project can also be found on thingiverse: https://www.thingiverse.com/thing:4129443
Cheers!
Thanks for your comments.
I ended up adding a counter bearing on the bottom to help with the belt forces, as well as a collar on the leadscrew above the pillow bearing to help with vertical/gravity forces.
@Phaedrux Hey thanks!
Great printer you have as well Similar Z concepts. I see you use two bearings (as far as I understood). Was that for the same reason and for peace of mind?
I also don't think it will be a problem, but what I was thinking is adding a counter bearing on the bottom so that when the belt pulls, the leadscrew won't budge. Something like this mockup:
Maybe an overkill, maybe not
Hello again,
I just wanted to share with you the last build I made, which of course uses Duet
(KEEVO = Cube in Greek)
(yeah the cables need some management)
It is also posted on Thingiverse -> https://www.thingiverse.com/thing:4129443
Any feedback is welcome of course!
Also, regarding the 3 leadscrews (which are only really mounted on the bottom), do you think that the forces from the Z belt will bend the leadscrews in the long run. I don't really see any bending though. It can be seen more clearly in this video which was the previous version (an hbot without duet and other stuff, but z axis is the same) -> https://www.youtube.com/watch?v=K0pcGKAQ4eA
Cheers
@bearer
So, I did the test and that confirms it
I incrementaly heated up the bed at target temp each time, unplug and measure it. Done at 21v although I don't think that matters much for this.
It is interesting to see that at about 50-60 C the resistance does not change much. Also at least in my test, the resistance stayed the same at 70C - 80C, so I presume that about 70C the max change has been reached.
Thanks a lot for I learned something new!
Thanks @bearer .
I will do your suggested test (heat -> measure -> heat -> measure) tomorrow and let you know what resistance measurements I came up with
Thank you both for extra information and help.
I decreased the power supply voltage for now, but I will order an SSR to do the switching, since I am losing about 100W bed heating power (down to 300W from 400W now). It's a DC 300x300mm PCB bed by the way.
I wouln't want to change the fuse to a 20A since 18A is the Duet rated max (better safe than sorry).
Thanks again