I did mention in my previous post some causes I think may be the issue. You might have missed them.

I did not see anywhere that you mentioned you confirmed the motor and screw was correct by comparing them side by side but at this point that is your only common link to your problem. Either the replacement should have been correct if ordered from anycubic and it was not or you thought it was correct if ordered from another source and was not.

I fixed the "flex" but it fixed none of my issues. The flex was due to the sliding block with the 3 bearings on it getting angled when the screw holding the middle eccentric one becomes loose and you re-tighten it at a slight angle. Apparently that can happen. Took me disassembling and testing everything else to find the bugger. Now there is no flex (play) at all.

First print came up without nthe new issue I mentioned in post #12 that "the prints come out as if the print bed is angled" but it did have the issue with the upper layers as in the photo in the OP.
It did appear to me that the build plate is moving lower than it should again for the first layer. I'm worried perhaps the first layer(s) is too close to the FEP film this way and may cause the first layer to adhere to both the build palte and to the FEP film as well, among other issues such as mechanical stress on the mechanical components, very subtle bending and danger of cracking the LCD display.
This is the first issue.

It is very subtle but if you watch the video here, at 0:29 you can notice that especially the blue pieces of the build plate which connect to the aluminum slider block with the 3 bearings gets visibly bent a little from moving too low: https://www.youtube.com/watch?v=DN7SU_e … e=youtu.be

I also don't remember how it was before, but if my memory doesn't fail me the build plate shouldn't keep moving so much after the beep at 0:28. It almost feels like the motor is being instructed to do some extra steps which it shouldn't. Am I wrong?

Second issue. When I tried printing something bigger, the next print the other issue I had before with the built plate getting bent and the print coming out accordingly came back. So the flex was never the root issue for anything...

Here is the build plate during printing the second print: https://i.imgur.com/LAzWX8z.jpg

Here it is out of the printer with the printer part on it: https://i.imgur.com/DBsjBvn.jpg
As you can clearly see the bent build plate is what caused the print to be bent. Their angles are perfectly parallel to each other.

Here you see the build plate moving up then down for a new layer: https://youtu.be/0QFUF8WztSM
You can hear a clicking sound like when a stepper motor is turned on, although I don't know where the sound is coming from. Not sure if that is normal. At this point the build plate wasn't bent yet. Video starts at 0:35.

Here is the bent build plate moving up and down for a new layer. Not sure when it got bent but was after the first layers: https://youtu.be/ndEKoOee0t8

My only guess is because the build plate moves lower than it should, the print stick to both the build plate and FEP film. Initially the FEP film doesn't let go and flexes a little but eventualy does, but first pulls the build plate from the adjusted angle. This is the only logical explanation I can think of.

Any ideas? I am getting quite desparate here.

It's pretty tight. There is some flex to the build plate but the sound is from the relatively thin lead screw being bent and made to hit the aluminum hole. There is flex if you push and pull on any machine, like my 4030 CNC miller and my aluminum Ender3.

We are missing the bigger issue here even if the above is an issue as well: the build plate is moving lower than it should. The pressure from the build plate being forced to move lower than it's minimum z height makes everything flex. That's the core issue in my opinion. Any ideas what may cause a seeminly properly calibrated (Home and Z=0 positions) LCD prnter to have the build plate move much lower than it should during printing?

After pondering your video and looking at my own printer, I think you're dealing with two different but simultaneous problems:

One is the 'flex'.  The lead screw raises and lowers, but does not provide structural stability...all that occurs with those bearings and that vertical aluminum race.  You shouldn't be able to move the build plate enough to bend the lead screw in the first place (mine does not move at all).  Something is physically not right in the Z race.

The second is the homing. When you press the 'Home' button in the Tools->Move Z menu, it should optically home...which is not the same as zero.  Home is higher than Zero.  It seems to me that your optical sensor is dislodged.  These problems may have appeared when the other repairs to the printer were being made.  I don't think you're going to be able to properly home or accurately set zero until you eliminate the play in the Z axis.

-Kevin

The D7 uses a blade and sensor as well. Leveling is achieved by loosening the 4 screws that bolt the plate to the Z stage. This allows the plate to slide up or down 15mm with no regard to the Z stage.

You then lower the stage using the motor controls to the point where the sensor makes it stop. You then press the plate down on the film making sure it is down on all 4 corners.  While holding snugly against the film you tighten the 4 screws and your build platform is leveled and zeroed.

Like I said, I have re-levelled and re-zeroed the machine several times after the issue appeared.

I checked the forum and the only thing I haven't tried is what you quoted. I'll try that but I'm not keeping my hopes up that manual hand rotation of the motor for settting Z=0 vs by the stepper driver will change anything.

Other ideas are welcome.

Thanks.

It's pretty tight. There is some flex to the build plate but the sound is from the relatively thin lead screw being bent and made to hit the aluminum hole. There is flex if you push and pull on any machine, like my 4030 CNC miller and my aluminum Ender3.

We are missing the bigger issue here even if the above is an issue as well: the build plate is moving lower than it should. The pressure from the build plate being forced to move lower than it's minimum z height makes everything flex. That's the core issue in my opinion. Any ideas what may cause a seeminly properly calibrated (Home and Z=0 positions) LCD prnter to have the build plate move much lower than it should during printing?

The lever on your Z stop switch could have been bent over time so it allows the plate to move further down. I would redo the leveling and zeroing process.

Here is a forum where people are losing Z on your very machine..

https://www.thingiverse.com/groups/anyc … opic:32995

One guy did this which sounds very simple..

"I had this same issue... Its a bit unorthodox but I selected home, manually turned the z thread till it was nipping paper... Set z=0 and then pressed home again..."

I would read through all of those and see if any of them could apply to you.

We are missing the bigger issue here even if the above is an issue as well: the build plate is moving lower than it should. The pressure from the build plate being forced to move lower than it's minimum z height makes everything flex. That's the core issue in my opinion. Any ideas what may cause a seeminly properly calibrated (Home and Z=0 positions) LCD prnter to have the build plate move much lower than it should during printing?

Check to see that the eccentric nut is tightened correctly:

https://www.youtube.com/watch?v=f7gYTpBT3uk

-Keivn

-Kevin

-Kevin

The issue didn't go away. There seems to be a new issue now, or one I hadn't noticed due to the other issue. The prints come out as if the print bed is angled, lower towards the door and higher towards the other side. I am 100% confident the bed is homed and leveled perfectly. I payed good attention to how the pritner is printing and I found an issue: the bed moves lower than it should and bends slightly, and bends back as it goes up to move down again for the next layer. I have no idea why this happens. I have reset the Z=0 height several times now and the issue persists.

Note that I had replaced the motor of the printer but made sure to get the one with the same lead screw with the same pitch and lead (2mm) from Iverntech. Two of the pins had to be swapped for the motor to rotate the correct angle but other than that it seems to work fine. Not sure what the issue is.

I have updated the firmware with the latest official one as well with no difference.