I sent you the file from the print in the video (directly from the source) now to try this primitive again…I have a feeling a new mousepad is going to be born 
I’ll give it a shot today! 45m left on my own test prints and I’ll see what I get when I can load up the print.
I made a 270x270 at 0.2mm in Fusion and will run it with my tweaked settings. Should be done in half an hour.
Really happy I did this test. It looks great with the only “issues” being where previous prints showed through because I didn’t clean the bed.
My U1 is in an enclosure. I kept the U1 door slightly ajar but zipped up the enclosure. I get lectured all the time for printing PLA too hot; however, it works just fine for me!
From the Vision Miner Nano leftovers and previous prints:
I have cleaned my plate so much If there is anything left over it is meant to stay! 
Attached are the following:
- My STL of a simple 270x270x0.2mm
- Try with my settings, if it’s good, then with your settings
- U1 Top Layer Test_0.2mm.stl (684 Bytes)
- Try with my settings, if it’s good, then with your settings
- Win11
- “C:\Users\USER NAME HERE\AppData\Roaming\Snapmaker_Orca\user\default\process\”
- 0.20 Standard @Snapmaker U1 (0.4 nozzle) - fats Test.json (427 Bytes)
- If the .info file is needed, I’ll have to mail that to you, as the Upload won’t allow it…
- “C:\Users\USER NAME HERE\AppData\Roaming\Snapmaker_Orca\user\default\process\”
Am I the only one using extrafine (default from when I got the printer)? Could this be the cause of all my headaches? 
Then again, the G-code from Snapmaker forces settings very similar to yours, and I still had janky edges. This is what I am working with currently based on SM tech support/print team. Tonight I will print the dreaded mousepad again.
When I sliced my first print and saw how ridiculously long it would take, I immediately checked what settings they had defaulted. I changed to Standard 0.20mm and then added my own tweaks; simple things like Wall loops and Skirt loops.
Maybe a complete wipe of SnOrca and fresh install? Have you tried both Orca and SnOrca?
I’m so relieved to see someone else talking about this problem, this has been the bane of my U1 and it’s exactly the same story as yours!! My first layer is fine but I get terrible rippling and grinding at the top of any large print I do on the U1.
I’ve tried about everything I can try - adjusting Z offset, manual bed levelling, maintaining the rails, calibrating the filament, tweaking flow rate, different layer heights, different materials, printing on different surface, etc and nothing fixes it. The only thing that improves it is printing slowly - instead of waving and grinding I just get a fine stepping pattern across the whole print, kind of like ghosting or VFAs. At least for me, this is the cause of the grinding. The pattern gets more extreme at fast speeds and bunches up to the point of grinding. Regardless, it feels pointless to buy a fast printer with high flow filament to have to print slowly with it, all for a lower quality result than my other printers. I’m almost convinced there’s a mechanical issue with my U1.
I’ve been in contact with support the whole time - they have made me change layer height, reset profiles, re-tension (again), different filament profile. All that has happened is I have wasted a spool of filament and have now a stripped screw in the tensioner I have to deal with. It’s really frustrating - as nice as support is, I’m just repeating myself and repeating prints with almost identical parameters. I’m not afraid of tinkering with a printer but this is an exercise in futility!
I’m holding out hope support will either fix the problem or replace the printer. I’m hoping you find a solution as well, it’s not fun to buy a new printer and get nothing but failed prints from it
Welcome in @badprintsonly Please share an STL of what you are having issues with. I’ll try to make time to print it.
Your top shell thickness seems to be 7x0.08mm, this means you have 0.56mm top thickness.
Did you try to increase the count to 13 like I mentioned in my first reply? Does it help or stays it exactly the same?
Printing in 0.2mm layer height should minimize print time and increases the stability of the model.
Using more top layers is what I was thinking and have tried even increasing the infil to 35% but the SM print team wanted me to reduce it to 7 and 15% respectively, which seems odd. The pic is the print from when I came home today. Not much scraping (you can see some). I am wondering if I can slow down the print speed, if it may help, because absolutely nothing else has worked. This, unfortunately, as @badprintsonly mentioned, defeats the purpose of the printer. I will give Snapmaker kudos for their efforts and for offering to send me some filament to replace the gobs I wasted so far while troubleshooting.
Thanks for the offer, I’ll upload it when I’m back at home. It was nothing special, a 28x10cm rectangle of 3mm thickness placed diagonally on the build plate. Don’t worry about making time to print it - Snapmaker support printed it on their office printer and it was perfect, meanwhile mine (with same default parameters and bundled filament) ranges from completely destroyed on the top to ripply to (now) a lighter wave pattern. None have that almost ironed look I can get from other printers. I’ll get a flat surface eventually though
They suggested the same to me of increasing top layers, I didn’t find it helped when the nozzle is actively grinding. Thicker layers helped disguise the problem by the time it reaches top layer (more room between nozzle and surface reduces grinding, after all) but it’s just hiding it.
One thing that did help me was swapping to a 3rd party plate. I don’t know if I got a bad plate but despite repeatedly washing with dishsoap and lightly scrubbing it, all my big prints warp at the center (but not the corners). It wasn’t obvious with thin prints but when I pushed two identical thicker large prints bottom side together there was noticeable bowing. After trying different heatbed temps I swapped to a CryoGrip plate and get zero warping and that made it possible to get flat top layers with slower printing, albeit with grinding still. I notice a lot of your images have more rippling in center, are you also having that problem?
Too much to go back through… have you guys disassembled the Toolhead and re-seated the hot end assembly? I have my hardened steel nozzles but haven’t installed them yet so I have no clue if I’m asking a logical question! Could something be loose and bouncing around?
Its not a bad shout, I remember that causing grinding on the Bambu A1 line. I’ve installed the hardened ends in my U1 and they align themselves tightly once you get the screws in. It’s worth checking but in my case I get the same issue on every tool - I’m not sure the U1 is as sensitive to this problem, but I’ll add it to the list of things to try
“Loose and bouncing around” is definitely a part in it though. I compared the input shaper graphs between when I first set up the printer and now and there’s some degradation. After maintaining the rods I can get the maximum acceleration closer to what it should be but it’s still got more vibrations at every frequency. I worry the fix is waiting deeper inside the printer, some hours of ripping apart 
I’m trying to not have Snapmaker tell me to keep my mouth shut but at this point I don’t understand how new units haven’t been sent out…
2 out of however many that have shipped seems within the margin of error from the factory! Multiple tests have been done by the affected users, Support, and Community members.
I’m guessing it’s more complicated than that and I should keep my mouth shut but from an outsiders perspective it’s discouraging. Especially since I keep raving about how happy I am with the company so far.
Yep, same problems, but only with large flat prints. Nothing seems to work completely, and the best I have seen is that last photo I shared. Even in that one, you can see some grinding has taken place. I do have a slightly slower print setup for later tonight to see if slowing the print speed affects print quality. I am trying to control what I change so I can isolate better. I’d print it now, but I am also working on a dissertation, and that is slightly more important than this. I would buy a 3rd party plate, but at this point, if that is what the problem is, I’d be surprised. I am glad to see im not the only one they told to wash the build plate with dawn . It seems to be their go to response though.