Voron 2.4 300mm Gantry Drop when powered off

[bcgreenbox]

Hello,

I'm troubleshooting an issue with the right-rear corner of the gantry on my Voron 2.4 300mm.  When I power it off, it drops about 15mm.  The other 3 corners stay put.  I am using the Galileo 2 Z drives. When powered on, I can home and level gantry, I'm just not sure what's going on with this one z-drive.  I checked the settings, gear ratios, rotation distance, etc., all look good.  Bad motor perhaps?

Here's a short video of it: 

 

[MrSprinklz]

Do the same test with the toolhead parked in a different corner and see if the drooping corner changes. If so, it can help to park the toolhead in the middle of the build plate or slightly forward to not have so much weight right next to one z-drive

[DennisM]

I think all 2.4s drop like that when the motors aren't energized due to the weight applied to the gantry at the back from the X & Y motors.

As you know, the QGL straightens all that out when actually printing - that's why the first iteration always pulls the gantry up in the back a lot.

[Jeffware]

None of my z motors drop at all when the machine is powered off. have you check for loose belts? not the primary long belts but the short belt loop underneath the printer.

 

[Dirk]

On 4/27/2024 at 3:45 PM, bcgreenbox said:

am using the Galileo 2 Z drives

It is logical actually, that a flying gantry will drop, once the forces keeping it together stops doing that. Certain larger motors that are stronger and can carry the weight of the gantry well, and people will think that their z motors never drop at all. But it does. 

The galileo 2 z drives are nice and beautiful and small and new and small. They are also very small. Did I say small? Well, this makes sure that it does not really hold the weight of the gantry. 

Those Galileo 2 z drives are also meant for smaller printers with a lighter gantry, like the Micron 120. Not for a 2.4 - 300.

The reason your gantry drops on that location, is because it is heaviest there. And like @MrSprinklzsuggests, parking your printhead in the front might reduce this dropping.

I have experienced that the correction for the first round QGL has dramatically reduced after I converted to CAN and an Umbilical  

So I can recommend that.

Besides the obvious of course, to get better Z drives.

I have seen a strange mod, that uses keybacks (Like with the Switchwire) on the backside where the gantry drops when you use weak z motors like in your case. So that would be a relatively fixing the beautiful (G2Z) with ugly fix. But an option

 

 

[jetcat]

I have the same setup as you have. I made a shutoff macro that parks the toolhead to Y=0, X=100. It doesn't droop anymore then with the original Z drives. Home + QGL, and your back to level...

[sandman50]

On 5/2/2024 at 12:02 AM, jetcat said:

I have the same setup as you have. I made a shutoff macro that parks the toolhead to Y=0, X=100. It doesn't droop anymore then with the original Z drives. Home + QGL, and your back to level...

Yes, park the toolhead at the back left. 

CAN would also help remove mass from the gantry.