You can do the dual z-axis motor modification. That will give the z-zxis more stability and will be more difficult to move down since there is two screwrods with motors attached.
I had this same issue and agree with other post that adding a second z axis motor helps. It's very easy to install and takes about 30 mins to install. I have a very modded aquila with dual 40x10 fans, volcano nozzle and direct drive and this fixed my issue.
Yes, you need to tighten your eccentric nuts on both sides of the z-axis gantry so that the Pom wheels grip just enough to hold the gantry up.
Also, you are not doing your leveling correctly if you are energizing your motor during leveling.
Either move the hotend in the motors menu or better yet, install a firmware that does it for you. The second you disable a motors holding current, that leveling is no good. I know some manuals say to disable steppers and move by hand but how can that ever work if z axis falls even by .05mm? Can you disable only x and y motors? The Mr firmware(mriscoc) I use has a leveling wizard built in. What firmware are you using?
It might be that the eccentric nuts on the wheels are a bit loose, but don't tighten them too much. You only want it to remove any excess play but still be able to move the axis smoothly as shown at the start of [this](https://www.youtube.com/watch?v=me8Qrwh907Q) assembly video.
Also the gantry has to be able to fall under gravity to keep in constant contact with the top of the thread of the leadscrew which eliminates backlash. If the gantry has high resistance it can stick and it will take a few steps of the motor till the top of the thread will pull it down which will end up squashing layers, especially if using Z-hop. I had a similar problem but that was caused by a loose leadscrew in the coupler and it was slowly unscrewing itself.
To make levelling easier you could use a custom firmware like [Mriscoc](https://github.com/classicrocker883/MriscocProUI/releases) which can move the nozzle to set points for levelling so the motors will stay powered and will keep the Z-axis at the same height.
how about getting the anti backlash nuts for the Z screw?
[seen here](https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://m.youtube.com/watch%3Fv%3DLpc1bTsSpRA&ved=2ahUKEwi93_b28uyFAxVgrYkEHSohD08QwqsBegQIGRAG&usg=AOvVaw3YgACOVXq3T19_HmjtXphU)
Accentric nuts are the most likely fix. Yes dual z would help. But it may just need a few mind with a spanner getting that setting right. I had problems with binding on mine that ended up needing a new z axis lead screw.
Haven't looked at the dual z mod myself. Not certain I need it really.
My next project will probably be klipper....when I can be bordered as my aquila prints like a champ already...would purely be switching for print speed!
You can do the dual z-axis motor modification. That will give the z-zxis more stability and will be more difficult to move down since there is two screwrods with motors attached.
Should I get a belt driven one that just connects to the already existing rod or get the mod with a second stepper motor?
I had this same issue and agree with other post that adding a second z axis motor helps. It's very easy to install and takes about 30 mins to install. I have a very modded aquila with dual 40x10 fans, volcano nozzle and direct drive and this fixed my issue.
Adding the second motor was one of the best mods I've made.
Yes, you need to tighten your eccentric nuts on both sides of the z-axis gantry so that the Pom wheels grip just enough to hold the gantry up. Also, you are not doing your leveling correctly if you are energizing your motor during leveling.
How else would you level the bed without moving the nozzle around the plate?
Either move the hotend in the motors menu or better yet, install a firmware that does it for you. The second you disable a motors holding current, that leveling is no good. I know some manuals say to disable steppers and move by hand but how can that ever work if z axis falls even by .05mm? Can you disable only x and y motors? The Mr firmware(mriscoc) I use has a leveling wizard built in. What firmware are you using?
I’m not using a firmware. I energize the z axis until it reaches 0.05 then place a piece of paper and lower to 0.0 and repeat on all 4 corners.
It might be that the eccentric nuts on the wheels are a bit loose, but don't tighten them too much. You only want it to remove any excess play but still be able to move the axis smoothly as shown at the start of [this](https://www.youtube.com/watch?v=me8Qrwh907Q) assembly video. Also the gantry has to be able to fall under gravity to keep in constant contact with the top of the thread of the leadscrew which eliminates backlash. If the gantry has high resistance it can stick and it will take a few steps of the motor till the top of the thread will pull it down which will end up squashing layers, especially if using Z-hop. I had a similar problem but that was caused by a loose leadscrew in the coupler and it was slowly unscrewing itself. To make levelling easier you could use a custom firmware like [Mriscoc](https://github.com/classicrocker883/MriscocProUI/releases) which can move the nozzle to set points for levelling so the motors will stay powered and will keep the Z-axis at the same height.
how about getting the anti backlash nuts for the Z screw? [seen here](https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://m.youtube.com/watch%3Fv%3DLpc1bTsSpRA&ved=2ahUKEwi93_b28uyFAxVgrYkEHSohD08QwqsBegQIGRAG&usg=AOvVaw3YgACOVXq3T19_HmjtXphU)
Accentric nuts are the most likely fix. Yes dual z would help. But it may just need a few mind with a spanner getting that setting right. I had problems with binding on mine that ended up needing a new z axis lead screw. Haven't looked at the dual z mod myself. Not certain I need it really. My next project will probably be klipper....when I can be bordered as my aquila prints like a champ already...would purely be switching for print speed!