Large prints warping
Hello,
I am trying to print a custom designed, MMU chess board on my MK3S+. It's split into four parts, and each part essentially takes almost the entire printbed. I am printing with Inland PLA+ on the powder coated Prusa sheet. I have had many issues with warping on the corners of the print. My solution so far has been to increase the bed temperature, which has worked better, but I seem to have reached a breakover point where the corners are still warping some and now the middle is rising from the bed. The print takes about 20 hours, and usually for most of that the print is not warping, just closer to the end it does. I have used a 10 mm brim around the outside of the model.
How can I get a good, large and flat MMU print that does not warp?
Thanks.
RE: Large prints warping
I don't know about the MMU specifically (gave up on it) but I doubt it has any impact. It's just not easy to avoid warping on those large objects.
Assuming Live Z is well calibrated and the steel sheet is clean (using hot water and fragrant-free dish washing soap), here are a few approaches that have worked for me:
- You've tried Mickey Mouse ears on the corners/brim around the model.
- Slow down print speed.
- Use Layerneer Bed Weld ( https://www.amazon.com/Printer-Adhesive-Layerneer-Original-Filament/dp/B079984GV5/ ). You only need a thin layer.
- If you have design control over your part and it's possible considering the intended use, you can try to round the edges and/or add holes to the base of the model.
- Combination of above. Usually, brim/ears does the job, or some Layerneer if needed, but large, rectangular objects can be a challenge.
RE: Large prints warping
Does PETG normally have a better time with large, flat prints on the powder coated sheet?
Also, is there any way to further customize brim from Prusaslicer other than brim width and inner/outer?
RE: Large prints warping
Hard to generalize. I sell a large model that I used to print with Sunlu PETG, and it took me a while to get warping under control. When I had problems sourcing that particular filament I switched to a different brand, Jarres, which I'd never used before. It's actually cheaper then Sunlu but it prints nicely and I haven't seen any of the warping issues. I guess my point is, there are many factors that can drive warping, including the brand of filament.
As far as the brim is concerned I don't think there are any other options in Prusaslicer . If I wanted a more sophisticated brim I'd design it into my model. Or you could try to use single (or multiple) layer high parts arranged around the model (which may work just fine with straight line models like parts of a chess board) which would give you more options. I haven't had the need to try anything more complex than Mickey Mouse ears myself so I can't speak from personal experience.
RE:
I am currently printing and assembling what is best described as a homebrew laptop computer. I'm doing this on an Ultimaker, not a Prusa, but the issues apply to both.
I'm currently trying to tweak things, using full-width test prints, to minimize warping. I am trying PLA, ABS, and ASA filaments. I would like to print with something more heat resistant than PLA, but so far the test prints with ABS/ASA show more of a tendency to warp. To give you an idea of size, the finished project will be 330mm wide (the absolute full width of the S5) and 237mm deep. (Thus no room for brim or ears.)
The piece I am having the issue with is the top piece that will hold the screen, and I would like to make this as thin as possible, meaning mostly hollow space for the screen assembly and that's what I think is mainly the cause of the warping issue.
In playing around with this, here are a few things I've concluded WRT warping.
1. Use an adhesion booster. I use the Layerneer cited above.
2. Don't OD on the 'elephant foot' compensation. I had this set a bit on the high side and on one ABS test print that obviously caused one of the corners to break away from the build plate. It created almost kind of a chamfer on the lowest layers.
3. I've found that a cubic infill pattern helps to control warping, as opposed to gyroid.
4. Ditto with increasing the infill percentage to 50% instead of the usual 15-20%.
5. (mainly for the ABS/ASA test prints) Preheat the machine and let it stabilize before launching the print. This is one of my practices for consistent quality ABS prints.
6. When the print is finished, let it cool, on the build plate, until it is almost room temperature before removing.
Now, to do if I can't get warping under control with the current design.
1. Increase the height to expand the full-height top side, above the hollow-out for the display, for additional strength to control warping.
2. (bite the bullet) Increase the overall thickness of the piece for greater strength and stability. (I want to keep it as thin as possible.)