The “OK” benchy was started at 35C chamber temp, ending at 42C
I then heated the chamber to 45C using 110C bed temp and Aux fan for 10-15 mins.
I ran the same print again, and had noticable straining/noises midway (sorry, didnt document layers), until an XY crash (again, didnt document the layer). Temp was still about 45C when it crashed.
EDIT*-- I cooled the chamber, and ran the same print again at “Low” temp, starting at 35C- ending at 41C, and the print finished without issue and looked just like the first “good” print posted.
Its not just limited to ABS/ASA either. This happens to me regardless of filament, and only if the chamber temperature is above 43c. If I print with the door open, the chamber temp stays low enough to where I can finish the print, but the quality suffers for the same reasons why youd want an enclosed chamber.
Understood- Its just ASA/ABS is what I have problems with/ and tested. It would be great if someone tests other filaments at the low/high chamber temps to see if the problem occurs/follows suite.
From preliminary results- it would be great if members NOT facing issues, could test ASA/ABS printed at “low- <40C” and "high >42C " chamber temps to see what occurs.
You probably just need to change your fan speeds until Bambu makes an update to fix their fan changes.
I just printed a part in ASA. I changed the part fan maximum speed to 30%, the auxiliary fan was 0% so I left it like that, I changed the chamber fan to 10% while printing and left it at 70% after printing.
I only changed the fans for the model I was printing and didn’t save the filament profile so that when Bambu fixes it I will so be using the default values
Maybe somebody with more ASA experience can suggest different fan speeds.
For those successful with printing ABS/ASA, how old is your printer?
My thoughts here is that maybe Bambu Labs updated/changed components and this could be an issue.
My printer only a month old and I’ve never been able to successfully print ABS.
My printer was exchanged within warranty due to sticky carbon rods, and the printer before this one wasn’t able to print ABS either.
I’m pretty convinced the issue is what NeverGM stated- chamber temp related.
So next is Why?
Why does the inner temp of the printer seem to effect this so repeatably?
Could this be a heat-creep issue?
I don’t think I believe the chamber temp is enough to cause any mechanical issues. The fact that it is repeatable- failing when above 42-43c, and working fine when below, seems to point fingers at the hotend doesnt it?
ASA/ABS contracts when cooled, which propagates in warping, resulting in some cases lifting from plate, deforming parts, layers detaching.
Higher chamber temps (including from preheating pre-print, and during print) help a bit to alleviate those issues from excessive cooling at wrong times. Given that X1E with built-in chamber heater can go upto 60C, i’d say that such temps should be safe for most stuff in printer. Not as if no or insufficient cooling is answer, but varying and/or wrong/excessive cooling at wrong times often messes asa/abs prints success/quality.
My “abs routine” usually is:
plate temps at least 100C (and maybe also higher nozzle/print temps). Use brims/mouse-ears.
if large printed part, add plate clamps
disable aux, and especially chamber fan (to really disable later worth enabling filtering extension in nozzle/printer, and then set speeds to zero for appeared exhaust (chamber) fan in filament profile, otherwise seen it kicking in from time to time). Helps with non uniform one-side cooling and rising overall chamber temps
preheat pre-print at least 45C
consider evening out min/max cooling to reduce varying cooling/warping induced artifacts on sidewalls (and min layer time at least 15s). If overhangs are acceptable at less cooling, their cooling aswell to that of averaged. Lesser chamber/print temps (uninsulated chamber) - part fan below averaged half, higher chamber temps - a bit more part fan.
dry filament - best filament.
If one has added some extra heat insulation to printer, possibly average print temps in chamber might linger around 58-63C, and also preheating (manual plate temps set to max + enable aux fan) happens faster.
@JonRaymond, can you also mention your bed temperature (100?) and fan speeds like the the part fan min and max speed, the auxiliary fan, and the chamber fan while printing and after printing?
The fan settings are still set to default. As seen in the pictures the Part cooling fan is the only one active while printing and usually is about 30%.
I manually turn on the Aux fan as I find this helps to speed up preheating the chamber. The printer turns it off when it starts the print.
Preheating to 43c should be fine. My printers seem to level out at about 50c so that’s where most prints start at cause I often get called away before starting the print.
I don’t use the chamber fan during or after the print.
The latest Bambu update changed some of the default fans for ABS/ASA. These are its latest default settings:
Part fan max fan speed threshold: 50%
Auxiliary fan: 0%
Chamber fan while printing: 70%
Chamber fan after printing: 70%
I changed my settings to:
Part fan max fan speed threshold: 30%
Auxiliary fan: 0%
Chamber fan while printing: 10%
Chamber fan after printing: 70%
Do you think having the chamber fan on after printing might cause issues?
I am pretty sure that the changes Bambu made to the fans are what’s causing people their problems. I think if they change the fan speeds to what you posted or to what I wrote above, they will solve their ABS/ASA issues.
Several people in the past have suggested setting the bed to 100C for ABS/ASA. For the part I was printing, I tried with the default 90 and the part (pretty short part) had a very slight warp on the right side, I tried a regular brim with the 0.1 spacing and it also warped the same. I then tried 100C without a brim and there was no warping at all. I didn’t bother trying the 0 spacing brim since the 100C bed worked well.
I hate the 70% default they put on. The last thick ASA part I made showed cracking the middle of the part, I believe because of that.
I’ve noticed they have been changing the fan settings on ASA for the last few months. Some good, some terrible. You really have to scour the cooling tab before printing anything challenging right now.
