Okay that went fast. I figured it would take a day or two to get some eyes on this. And a day or two per topic. Let’s try something more complicated this time.
Z Axis drive system
I think we all agree on CoreXY, right? Three Z steppers so we can physically adjust the level before mesh leveling? I think those are givens right?!
Belted Z (with drop protection) or Leadscrews?
I chose belt because is less expensive (smaller BOM belts and idlers that are already needed elsewhere. Belts let the rail do the guiding of the motion with no outside influence from a bent leadscrew (look at HevORTs solution to this).
The downside is the drop with heavy beds. A 200x200 thin mk2 bed with a wood carrier plate does not drop very fast. So that means an added part is needed.
We can gear down the Z belts, that means an extra belt loop and gear set/bearing.
We can use a constant tension spring, ~$7 each, would need to be tuned to the weight of each machine. Something like this https://amzn.to/41WhWAh
Electronic brake. Mike M had an idea that I already ordered to try. These exist, Mini 2 Z Brake Board Kit | Lulzbot 3D printers they cost a lot. Mike’s idea was try this Amazon.com Best bang for the buck, short one stepper coil and the stepper will hold (or possibly drop extremely slowly) even with a very heavy bed.
Let’s get to the frame after we have some of the basics knocked out. I think that is going to take two rounds of choices.
The only issue with the leadscrews, I think, is maybe length? The Voron Trident is usually limited to 250mm height because of sourcing of longer lead screws, and I would guess maybe more likely to have them bent, etc and have binding/quality issues?
Perhaps as an alternative moving the Z motion to the Core XY assembly and keeping the bed stationary at the bottom alleviates that problem since the the XY gantry weight will not vary by as much as the size goes up? I’m not sure of the benefits of one moving over the other
Having the bed stationary at the bottom, though, does remove the possibility of having a false bottom with an access panel to bottom mounted electronics…
No question on corexy, that’s a given. And I love the bed tramming with the multiple steppers so to me that’s also a given.
I really like the belted Z over the leadscrews but we have got to come up with some kind of drop protection for SURE. I think I may have one of if not the heaviest V4 bed around and I have no problem with testing anything y’all want to try.
This doesn’t bother me any. They should all be easy to get off the shelf parts from amazon or anywhere else. I’m not building this printer because its the best bang for the buck. If I wanted that I would just pick up another creality off amazon. I’m building it because its a better printer that has an awesome community around it. If price is your main driving factor then to me you shouldn’t even be talking about a custom built printer.
This just sounds like a tuning headache to me but I have zero experience with it and could be very wrong.
I like this idea as well, but it has to be done right and “fail proof”. I look at it like this. If you did the geared motors then once you build it that’s its, its going to work. This needs to be the same way. Not something your always having to tweak the code for on every update or something like that.
Personally assumed CoreXY, but have the cool kids/startups/corps come up with something newer/better?
Is three Z steppers a given? Expecting many people to build 300+, if so, although 3’s enough for smaller builds, would 4 steppers improve/simplify the frame design/assembly/accuracy/stability? Asking since we saw 4 on recent large Vorons. And saw folks with large builds struggle to get Z tilt level within desired tolerance.
Nice. Personally appreciate v.next explicitly designing for drop protection through hardware and/or software changes. Already on my todo list for my current build, priority got bumped up after observing Jonathan’s boards.
Figured the 84oz steppers are so beefy we don’t need to accurately tune the constant tension springs? (EDIT: Hmm, this isn’t relevant to drop protection) Boards should be able to handle slow drop.
V1E Brake/protection board that supports 3-4 drivers anyone… Useful for overly man/person handled CNC’s too.
The other downside along these lines is not easy to make a 'parametric kit. If this goes well people could buy the basics with enough belt and add their own other parts. Lead screws means ordering custom screws for custom builds. No a huge concern but falls into simpler BOM I belive.
I think this is a direction that needs to be heavily looked at. Even more so for anyone looking at the higher end buildplates that are even thicker and heavier than what I am running now
At what point is this becoming a problem? Do they use a bed carrier plate like we do?
I guess I have two options here. The current Z system can actually add as many Z as you want with no frame altering, just add an upright for each Z and change the carrier plate. so it is an option that can be had with very little altering if we end up with something similar. Or we make sure it conforms so it is an option…
I would suspect the bed carrier is a big key here. I don’t understand the problem enough if the sag is not the issue. If the back corners are out of wack adjust the springs a bit to torque it differently on the carrier plate.
I would think two steppers, three (assumed linear rails), and an extruder would be pretty heavy itself mounted on something thick and strong themselves. It can’t possibly be that different.
To me this more comes into play if we mount the bed at the bottom and move the corexy gantry. Then I think one at each corner would be better for even distribution no matter where the print head is at. But you are the engineer not me LOL
plus heater, insulation and a glass top. Idk reaching in there and trying to hold it up it gets real heavy real quick lol. maybe I’m just more out of shape than I realize. getting weak in my old age
Personally like the belts, providing drop protection/halting is handled.
, was recalling the bed leveling time/effort that Jonathan went through.
Asking about 4 steppers since we’re seeing that on larger non V1E builds ( >300). Keep steppers in the corners frees up the rear area for tool changers and such.
Personally, ignoring tool changer requirement, and time/effort to accurate cut and assemble back middle Z. For MP3DP v4, I do like the resulting 3 stepper setup which leaves rear corners empty for a spool to fit, even for a 250 build.
Getting an Enraged Rabbit Carrot Feeder kit honestly sounds like the time/money smart thing to do. Ideally, IF I ended up making multi material, would want to avoid it excessively pooping out filament like a rabbit, Bambu and similar. To save print time and material. However, maybe trying out ERCF for a bit first is a more sensible next step, before/instead-of going down a $$$ multi extruder hot-end rabbit hole.
Stationary bed or not? Crap I have not looked into it at all. The only thing I see I don’t like is the extra long reverse bowden. But that does not have to be the way they show in the video, it can just be mounted to the rail proved you pull from the bottom so as not to fight gravity.
Ditch the glass and go PEI! There must be some fancy mag beds that let you use any material you want without having to heat a 1/2" aluminum plate and a hunk of glass (real good insulator).
, was recalling the bed leveling time/effort that Jonathan went through.
