[ENHANCEMENT] MK4 Live Z adjust permanent

[griznold]

Enter what type of printer or upgrade the enhancement applies to. Printer type - MK4 Optional upgrades - Orignal

Is your suggested improvement related to an existing problem? Please describe. The live z adjust is also available for the MK4. But is not sent permanently. I like to have this feature to behave like at the MK3, where it is permanent. (Value is kept even after power reset). The standard load cell bed leveling was not sufficient, to create a very smooth surface. And it looks like, if this varies from printer to printer, to create consistent results. So the easiest solution would be to make this setting permanent.

See discussion here: https://forum.prusa3d.com/forum/english-forum-original-prusa-i3-mk4-hardware-firmware-and-software-help/any-way-to-change-the-z-offset/#post-675656

Describe the expected functionality The live z adjust should be permanent stored.

[mix579]

I don't disagree with this idea but I found things to be even more complicated. The "always perfect" first layer is really not so perfect if I use a satin or textured sheet because the rough surface of those sheets seem to throw the load cell off. I need to dial Live Z manually down by about -0.025 to get good adhesion. So storing just one value in fw wouldn't really help me. What I need is a sheet menu like we had on the Mk3S — but of course that would be admission that the load cell is really not better than the old PINDA…

[griznold]

That's an important point. But physically it seems logical, that a smooth and a rough surface will lead to different results if they're probed with a big object. So even with a good contact point, the rough surface should then need more filemant to fill the small valleys. So my hope was, that these factors were negligible, but I mainly used the satin sheet so far.

[Skaronator]

The best solution from a hardware standpoint would be if the printer automatically knew which print bed is used. This would be possible when the print sheets have a special location outside the print area where the load cell can check for a raised bump. Somewhat like a punch card reader but instead of having a hole in the sheet it would be a raised bump that could be glued for already produced sheets.

[xilni]

This applies to the 5T XL as well, for PETG with the textured sheet I have to get down to -0.125 mm for the first layer using the dial since the Z offset parameter in the slicer doesn't seem to affect anything.

[vmLOGIC]

The issue with my Prusa MK4 only occurs with the textured sheet. Using it is like playing a game of chance. This is a very frustrating limitation, especially when printing with PETG. With the Prusa Mini, I almost exclusively used the textured sheet, so I ordered it for the MK4 as well. Apparently, without reason. I would classify the issue here not as an enhancement but as an error.

[peterjhl]

+1

[stefanbayer1]

Having the same exact issue. Why does no one at Prusa adress this. Also the support was not helpful at all. I would say my MK3S+ was better in terms of print quality and reliability of the first layer than my Prusa MK4 is after 3 moths of use.

[vmLOGIC]

Exactly! This question has been left hanging for 4 months now, and Prusa hasn't bothered to respond in any way. It's truly infuriating! Yesterday, I thought I'd give it another shot. After all, there have been firmware updates in the meantime. Your comment just confirms that there has been no improvement. I'll soon have to shell out for a new PEI shield because PETG is slowly but surely wrecking the old one.

[pjvenda]

Considering the poor adhesion issues on the satin and textured surface, it would be most welcome to have indexable permanent z-offsets stored on the printer.

[ViceVerus]

I own an XL and have been chasing an issue for months. I had gaps in the first layer on all first layer infill types, moving to the 0.4mm from 0.6mm minimised the issue to a reasonable level with monotonic. I like to use the Hilbert as it can minimise visibility of the lines to nearly nothing. This worked on the MK3S very well and I produced XXXs of parts with perfection. This was by manual Z calibration.

I have found in general that the Load Cell is very repeatable but I don't think it is that accurate. The printer assumes perfect accuracy and does not allow you to override. 0.05-0.02mm even with monotonic getting rid of the tinny pinholes at the point it reaches the perimeter.

I would really like this to be raised further up the priority list for all printer types that use the Load Cell

[github-actions[bot]]

This issue has been flagged as stale because it has been open for 60 days with no activity. The issue will be closed in 7 days unless someone removes the "stale" label or adds a comment.

[vmLOGIC]

Before this issue is closed, a statement from Prusa would be appreciated. Why should we write issues and contribute to product improvement if no one reads them?!

[ltlowe]

I was not even aware we can do a live Z adjustment on the MK4, but if the force sensor isn't giving the correct values, it would be a nice backup. In general I've been having issues getting the first layer correct on my MK4, fw 6.02 when using a 0.6mm nozzle. Similar issues I have found and added too are https://github.com/prusa3d/Prusa-Firmware-Buddy/issues/3264 and https://github.com/prusa3d/PrusaSlicer/issues/11271

[m00dawg]

Been at this for 2 weeks now. After numerous live chats, a replacement loadcell, factory resets, firmware upgrades, I have found that just bumping the z-height to +0.04 seems to remedy my first layer issues. Maybe it's something with my particular filament but while the XL seems to have a great first layer stock, on my MK4 it's just too close to the bed (consistently). It's "fine" probably for most prints that don't heavily rely on what the bottom looks like, but it makes it look kind of ugly with inconsistent lines and gaps. This is because it's displacing filament being too close to the bed.

Bumping the z-height 0.04 solves this and seems to do so consistently. Since I can't save the offset on the printer, I'm forced to do that in PrusaSlicer which means I might have to have multiple sliced models between printers. This is far from ideal. I'm not sure why Prusa is so stubborn about not offering this. If it's a question of not having new users mess something up, hide it behind an advanced users menu with a disclaimer. Invalidate my warranty if you must, just give me this feature.

Everything else about the MK4s has been glorious but it just surprises me the MK3s in this case is actually better. Granted my use case may not match most but taking away this feature is just a step backwards. And it cost Prusa money and time (in having to deal with all my live chats and loadcell replacement) which could have been avoided.

[griznold]

So I'm still using the Offset in the slicer for two MK4 now. I would really appreciate the simplest solution, so that each printer can be adjusted and keeps the value. Even an additional warning can be placed, to that No one ist doing this by accident.

I would think, that a more complex solution as a function of material, sheet type and speed would be maybe more a problem itself, than an easy solution.