This is essentially a large parts tray (290mm x 226mm) for modelling. Warping in the middle of the print, looks bowed up. Wierd that the edges are fine and the middle warps… Also the middle of the print almost looks for lack of a better word here, wet. A lot more shiny/glossy than the edges. I had a smaller print exhibit the same issue with warping, but didn’t pay it much mind when that happend as it wasn’t product affecting. But this is…
For PETG, I used Aquanet purple can to help with releasing a bit, I can try without it. Also I am starting a print right now in PLA with no Aquanet.
Enable “enhanced air filtration” in the printer profile. Then go to your filament profile’s cooling tab and enable the chamber exhaust fan. Then set it to 10%. You may even be able to turn it off completely.
Let that chamber warm up a bit for PETG. I usually run mine between 40°c and 42°c for pet and PETG by controlling the exhaust. Helps mitigate the warping.
All it does is gives you control over what speed the exhaust fan runs and also allows you to set it so it runs after the print completes if you want it to.
I see, actually very useful and should’ve been on by default for H2D.
With it on (under printer), but not ‘activated’ (under filament cooling), does it just behave like default with auto exhaust fan speed then? imo, terrible UI wording.
Bambu is too worried about clogging the extruder, tbh I think they really should change that into an option that you can switch on off during sending the printing task.
The PLA print just finished. Same warping as the PETG. Bows up in the middle of the print, like the bed is low in the middle. Bows to the middle on both the X and Y axis, essentiall the very center of the print is high. But no signs of adhesion issues on the bottom of the print, and the layers looks good too. Generally with warping you will get some bad layers, so maybe my print bed?
Edit: checked my bed the best that I could, print bed seems ok, not perfect, but shouldn’t do this. Put the part back on the bed after it is raised above the bed, so…
Maybe it is just the part/print? I tried to heat up the print to get it to go back to flat, it starts bending the other way, but when it cools it goes right back to having that bow in it.
I’m going to open a ticket with support, I dread doing that because of the hassle, but yeah…
That is a good question. I haven’t tried not enabling it in the filament profile to see what happens. I would imagine it would act as it normally does by default.
It behaves as if the feature was never activated in the first place.
However, be aware that if you enable this setting while using the chamber heater, the exhaust fan will not run during the print. Instead, it will activate after the print has finished, while the chamber is still in heat mode.
Vill du att jag förtydligar att detta kan vara ett problem för vissa filament eller bara låta det vara tekniskt?
Ok, I do think it is my print bed. Here is a pic through the glass that looks like the bed is warped. Also using the side of my 9” calipers as a straight edge. Need to get an actual straight edge.
I suspect this is the answer. I found the screws to adjust and did a quick adjustment and I am going to try the print again. If it is any better, I will go through the crazy process in the wiki.
I’ll mark this as the solution if it pans out,
Thanks!
EDIT: Going through the wiki for the tram leveling I found this tidbit, this is at the end of the procedure.
" The following screw(front) does not need to be tightened after leveling(tighten and then loosen 1/2 to 1 turn.) — it is designed for transportation protection . Keeping it loose helps prevent the bed from lifting too high in that area. Over-tightening may cause an uneven bed surface."
This is the front screw on the under side. I guess this screw being too tight can lift the front of the bed and cause an uneven surface… lol.
After a lot of experimenting, I have found out what I think the issue(s) is/are.
Yes, the bed was warped but thanks to @hotellonely I found the wiki to adjust the bed and was pretty successful doing it. I also got an actual straight edge to check it, and it looks pretty good.
This helped the issue, but did not completely reslove it.
It is also my print, this is a large parts tray with a 3mm base, but plenty of sections on the top. My working theory here is that the base has so much material compared to the top that when taking the thermal contaction into account it shrinks the base compared to the sections and creates a warping effect towards the middle of the print. PLA doesn’t warp as much as PETG during my testing, I haven’t actually checked on whether that correlates.
Making the base 1.5mm thick instead of 3mm made a difference, this follows my theory, but there is still warping… I don’t know if I want to go below 1.5mm. Maybe try printing the PETG a little cooler? What is the min nozzle temp I can get away with? I think I could also decrease the bed temp.
A good way to avoid warping on large PETG prints is to use PETG-CF or GF. The fibers in the filament prevent warping. Thats the only type of PETG I print with.
Yeah, but PETG-CF sticks like epoxy to the build plate. I have honestly ripped prints apart trying to get it off. I have been using Aqua Net and it works well, but with a print this large I am kind of hesitant.
