I tried to print a small part using ASA, and there are some issues with the result.
Here are some photos of the printed part:
I printed on the textured PEI plate, so, for reference, the textured surface is the bottom part.
The bottom of the part is supposed to be flat, but at the corner there is a little incline, so its supposed to be like:
_______
| |
|____/ <- small corner incline intended
As you can see from the photos, there are mainly 2 problems:
- some warping occurs on the bottom, making the bottom surface non-flat but warped instead
- the incline on the bottom corner is not printed well and looks weird from any side
I was printing with pretty much default settings. No support, 100% infill, hotbed 100°C, nozzle at default temps. I also lowered printing speeds for inner wall from 300mm/s to something like 250mm/s.
How can I improve the print to make the bottom part come out well?
I was thinking:
- increase hotbed to 105°C or 110°C (I printed ASA before and managed to get a perfect flat bottom layer, and I think I used higher hotbed temp)
- add supports to make the incline at the bottom turn out well
For the glitches on the side of the part, where the lower couple of layers look weird, I have no idea what could be causing this (first picture). Maybe this is also a result of warping?
I installed an addon chamber heater but if you preheat your hot bed and wait until you chamber hits about 60c before starting the print that should help with the warping. You also might want to try supports.
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Yep, that’s pretty much textbook shrinkage. Unfortunately, that design is just playing into the problem if anything. ASA likes to shrink a lift a bit anyway and your design just give it a head start. If that component is a necessary part of the design, ASA might not be the best material.
Your best bet is going to be chamber heat. I actually have my printer living in a closet along with my filament dryer. I usually fire the dryer and the heat bed up and get the closet on the warm side and the chamber preheated before I start printing with shrink-prone materials. I keep meaning to add a proper chamber heater…
Another thing that sometimes helps on those filaments is using a fairly wide brim, but I’m not sure it would be practical with that little bevel. Seems like it would be a hassle to clean up.
I repeated the print, with pre-heating the champer, and adding some isolation around the printer. The chamber was at around 35°C when starting the job, and went to 56°C during print.
The bottom of the part is now flat, so its much better. I also printed with smaller layer width, resulting in quite nice quality.
The small incline on the bottom, however, will not come out well. I added support, but removing it was difficult. Theres still something left of it which I could not remove by hand.
In addition, on the side, theres still the printing errors on the first couple of layers, looking like someone scratched the part. I dont know where this is coming from. How can I get rid of this?
Hmmm… have you tried printing it in PLA, just for the sake of diagnosis? If it prints well, you can shorten your list of possible issues considerably.
When printing ASA on the PIE plate I increase bed temperature to 110 °C (from the default 100 °C) and spray the plate with a whisp of 3DLAC. No issue with parts with worse geometry than yours, then.
You need to play with different settings for the supports. The default are for PLA, and sometimes they can even be hard to remove from PLA using the defaults. Each material needs different settings.
Settings to play with:
Top and bottom interface layers- increase the number
Top Z distance
Interface pattern -Rectilinear is recommended for ABS, so try it on ASA
Top interface spacing- A higher number means less contact points, 0 means solid contact. It’s weird, but sometimes going to a higher number makes it easier, sometimes going lower, or even to 0 makes removing the support easier. Depends on the material and geometry.
I’ve printed with ASA, but haven’t had to use supports so I don’t have any numbers I can recommend.
You can also try the different support types i.e., tree or normal
I printed the part with PETG first, and it came out perfectly. No issues at all. So its a ASA thing.
I had the bad at 107°, do you think the 3° make much of a difference? Can try it again of couse …
No, three degrees isn’t going to make the difference, and it doesn’t really surprise me that it prints fine with PETG, just wanted to be sure. ASA is great for some things, but it may not be the best choice for that part, simply due to geometry.
Short of getting your chamber up to a nice, even temp maybe as high as 50ish C before you start the print, I think you might be hosed. It doesn’t matter how warm it gets by the end of the print, since you can see most of the warping happening in the first maybe 5%. The way that one edge stick out there with nothing above it means it cools faster than the rest, and then it shrinks and the part warps. Bed adhesion isn’t really the issue, since the rest of the part is sticking fine. You’re fighting with a limit of the material IMHO.
You might have some luck playing around with the cooling tab on the filament preset. Maybe bump up the number of layers with no cooling or lower the exhaust fan speed, but I’m just taking shots in the dark.
Just to be precise, this is the issue:
I have printed ASA before, from a different spool, and it printed well. Could it be that the filament is not 100% dry? Or maybe printing speed issues? Should I print faster?
But seeing that the main issue is on the bottom, I might try to heat the chamber to 50°C before starting the print. It will take forever to heat the chamber tho, using only the heatbed.
I do see warpage on the bottom also I do know ASA has to be dry dry dry.
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Oh man… if there’s ever any doubt, just dry the filament first. That’s like step one troubleshooting to me.
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That second pic looks like two different issues to me. The warping at the bottom is what I’ve been addressing, but that other little spot could be due to some moisture and moisture definitely wouldn’t help with warping.
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Dried it for 4hrs at 70°. Gonna do another print, with reduced infill and speeds. Lets see how it goes.
Bambu recommends 8 hours at 75-85 for ASA. My dryer only goes to 70, so I tend to extend the times a bit, or a lot for things like nylons. I really tend to go overkill on drying because I’ve seen the difference. PLA not as much, but with most of the other filaments, drying is a huge factor.
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