Wasn’t that the whole point of this thread??? Lol
And I have to say after listening to your podcast and now actually pushing some its fun to watch
1 Like
Oh hell no, My arrogance thought…let’s let everyone walk me right back to the current build with some minor tweaks (belt terminations in particular…). 
Oh yes pleasant surprise can’t wait to see what else comes up…the v wheels are also a solid option. I am interested in those but I see both sides of it.
1 Like
If Belts, then uncontrolled falling bed seems like lesser evil/consequences than falling gantry.
Incomplete, one level up from mspaint, visual mockup of the reference XY plate and other CNC’d flat parts idea…
What about Ball screws for Z ? 
I’m not a new voice…but after thinking more about bed crashing vs expensive parts on gantry crashing…I lean more towards bed moving, even though I know there are some out there like the Voron 2.4 where the bed is stationary.
I haven’t looked that closely at it. I don’t know how the 2.4 deals with gantry drop or whether theirs is even belt driven…
We need a brake either way. I think a brake is less expensive and more parametric than leadscrews and anti-screw wobble connections.
But how does that change if the gantry moves up and down…I see V wheels doing the work and that plate non-existent.
As for the brackets, heck yeah. 3D printed ones even work well.
It is belt driven, with geared down stepper motors to make it hold without a needed outside break source.
Even more bend issues. I wanted them originally and you can ditch the linear rail…but they are very expensive and honestly unless you spend a ton they are not very straight. HevORT looked into that as well (I love his deep dives).
Here is something against the stationary bed.
During a power outage, the best case scenario is the gantry stays exactly where it was printing, the worst case is it slowly drops into the printed part. Geared or ebrake, any drop at all is going to drive your nozzle into something.
I much rather it fail safe, moving bed.
2 Likes
Expensive gears and looped belts are a bummer, I think a brake would be far cheaper.
1 Like
ok that’s just funny!!!
I don’t remember the rails being much more than what Dan said the wheels cost but I could be wrong, not the first time for that!
How much are SKR Pros? x 2 LOL
I know I know. Its just going to be making it work correctly.
Mike posted a video about it earlier that I haven’t gotten to finish watching yet.
How do the V slot wheels hold up at higher speeds?
Linear rails are usually seen as an upgrade.
I’ll admit, I have a Creality printer with V wheels, and I’ve never had any issues with them. No maintenance. Never replaced.
But I print slow because it’s a cheap machine. (cheap as in cheaply made more so than actual cost)
1 Like
Brake will handle unexpected power outage? As in, if power cut to home, then brake prevents fast drop, or dissipates energy/voltage/current to prevent controller death?
Will be interesting to see how material/labor cost for belt+brake compares with leadscrew+HevORT. Or are belt+brake clearly cheaper and easier to assemble/maintain?
Asking ChatGPT about Z printer mechanisms, feel like my mind’s stuck in a local maxima…
Should, the theory is it is a NO/NC relay. No power and it opens one side and closes the other. Shorting the coil and preventing or at least extremely slowing down the stepper. I do wonder why those others short both coils though…
Z only, slow small movements with “low” load. Giant bed and glass split three ways. With two wheels each.
I am sure there is no comparison. That style has linear rials holding bearing with magnets and ballscrews. That is just nuts. Badass but buts.
I am more wondering about a printed reducer gear and a looped belt with adjustments. but…they have already done that, that seems boring.
Linear rails are ~$15 for what we use per stepper. Two v-wheels are about $0.80 per stepper. We’ll have to get into that later, though I added it to the list. I am pretty sure the V wheel will win if we stick with an extrusion/hybrid frame.
Tensioning them though, that is tricky. Anything eccentric might add some cost. Surely there is a printable way to do it.
So I think if you power from mains power only, you miss the scenario where mains power is activated, but Motor power is disabled, Like when saving Klipper config, etc.
So maybe if you don’t want to interrupt the motor power initial flow, might need a little smarter circuit that can handle both cases. No power at all, as well as power, but motors disabled.
1 Like
As long as it will hold up I’m good with it.
I get where you are with this but I still have one concern. You planning on powering it from the power supply correct??? So when you turn power on to the printer that means the break turns off right? But that will almost always equal a crash wont it? None of my printers engage the motors until I start moving them.
Mike got there as I was typing
Initially I was just thinking dealing with motor power where the brake was active anytime the motors weren’t powered.
But I had not thought at all about the timing that Dan brought up
You end a print at Z max, so the bed is always down. I assumed we are only trying to protect if there is a power failure or an emergency stop.
I have 6 printers running now and The only time I have ever had them drop is a power outage. If I stop a print I use the button and stop it, then drive to Z max, or just catch them if it is real bad. 5x’s in the last year?
If there is an easy way to wire it when steppers are engaged that is fine but I think it is overkill and adds the need to use another pin and firmware edit. I was going for dumb failsafe in case of unexpected power outage.
So, Constant Tension Spring then?
1 Like