Disastrous first layer, artefacts in X axis  

That penholder is not well designed for 3D printing.  Rounded bottom curves and long hard-to-support bridges are unlikely to print well - but this is not your immediate problem.

Wash your print sheet.  Dishwashing detergent (Dawn/Fairy) and plenty of HOT water should get rid of those hand and finger prints,  pat dry with a fresh paper towel and hold by the edges only.  You may have other problems but that's the worst...

And before you try the pen holder again replace the fillets with chamfers, detach the main overhang and print it seperately, to glue on post printing.  From your description I suspect you are using grid infill, change to cubic.

Come  back if problems persist.

Cheerio,

RE: Disastrous first layer, artefacts in X axis

Model you linked to shows to me as zero downloads so I wonder how you printed it. Based on that anomaly I didn't download the 3mf out of precaution. Everything that diem said. Clean sheet, use cubic infill. Not the ideal design but you shouldn't see issues like this. Then again, the load cell on the MK4 has been anything but great in my hands, so I would also a) make sure the nozzle is squeaky clean before the mesh bed leveling (use a wire brush as the nozzle is heating up) and b) I would manually adjust the live Z by +0.04 or so as soon as the print starts. With newer versions of the firmware you'll see the option on the screen, with older you have to long press the button. Hopefully one of Diem's or my suggestion will help. Could also be a bad load cell. 

RE: Disastrous first layer, artefacts in X axis

thank you, I understand your concern with the file. It’s probably not even necessary to download it. I had more issues with the first layer than the print (I know it’s not the greatest design to be 3d printed, but I wanted to try).

I tried to disassemble almost the whole printer to clean and reinstall the y axis rods and now I’m trying first layer again and it seems that it helped a lot. 
Though I’m still getting failed test at the nozzle heater, so I will probably buy new hot end as this one is beaten up pretty badly, also it will be opportunity to try and use high flow nozzle.

RE: Disastrous first layer, artefacts in X axis

Ok, I was praising the first layer too soon. It started to do the waves again and it seems, that it is always perpendicular to the infill as seen on the picture, so I still guess, there is some stupid mechanical problem, but I’m not sure in which direction it could be.

RE: Disastrous first layer, artefacts in X axis

I was searching the internet a lot and I probably found the issue. It seems, that this thing is related to Y axis belt and alignment. 

https://www.reddit.com/r/prusa3d/comments/1f3tujj/issues_with_waveswrinkles_on_first_layers_on_mk4/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button

Im printing new sturdier Y axis motor holder and Ive also ordered new pullies and then I will print whole new tensioner for the Y axis. I hope this will be the solution to those artefacts and waviness in prints.

RE: Disastrous first layer, artefacts in X axis

That just looks like a first layer that is a fraction too low.  Dont have a Mk4 with the load cell but id manually tweak it up a tiny bit.

Much improved.  I agree with @neophyl; your live 'Z' needs to be raised slightly.

Cheerio,

RE: Disastrous first layer, artefacts in X axis

There's a very active open ticket on GitHub on this topic https://github.com/prusa3d/Prusa-Firmware-Buddy/issues/4254

Most people have luck using a +0.04 offset, including myself.    

Given the role of the "always perfect first layer" in their marketing and the fact that a good number of people can't get a decent first layer on anything but the smooth sheet, I consider this "Layergate" for Prusa. 

Curiously, while all my Mk4S's show the issue, my XL has been cranking out nice first layers (as of course does my Mk3.5). So I for one can't wait to upgrade to core one and hopefully this will go away so I don't have to babysit my printers anymore. 

RE: Disastrous first layer, artefacts in X axis

Thank you,

I will try the trick with the offset and I hope that it will be fine. Also those artefacts where sometimes even in vertical sides on prints, but I hope that the new tensioner of Y axis will solve that.