Getting horrible results with abs with overhangs and particularly bridging on my P1S. I have done a bunch of reading online and not found anything beyond turn the fan up and down (depending on whether its tips for bridging or tips for printing with ABS), adjust the nozzle temp and slow it down. I’ve tried a couple temp towers, the first i did on default generic ABS settings, then the second i tried slowing the bridging and overhangs down with minimal success in each one. I have also run a flow dynamics calibration and a Flow Rate calibration since.
I’ve attached photos of the temp towers in order and screenshots of my settings. Please let me know any ideas you might have.
I will add to this post with photos and updates of things I’m trying as I go.
For example a simple STL file won’t give you any temp changes for the layers unless you add them and that is surprisingly difficult in Bambu.
I assume you used Orca?
You towers do not show any sign of temperature change…
In general you want the nozzle temp just high high enough to allow for proper bonding.
Then for the bridging you adjust the speed and flow to get the least worse result.
Not enough flow and the bridge looks more like silk lines - but than can be beneficial at times.
Too much flow and the bridge gets too heavy and sags.
Same story for the speed.
Too fast and things might get thin and flimsy, even fail.
Too slow and the line just drools down more and more the longer the bridge is.
I downloaded it off thingiverse. It is a .3mf file and I swear I checked that it had different temps in the slicer before I printed though after going back and checking it shows its one colour, one temp, all the way through. Good catch! Would you recommend using Orca for the temp calibration or is there perhaps a good test file you might recommend?
I’ve only recently upgraded to the P1S from my old ender 3 where i was able to get this (see pic attached). I would like to be able to replicate similar quality on my P1S.
When you’re referring to flow, would that be the “Flow Ratio”? I’ve completed the calibration within bambu studio, would you say this is a pretty accurate calibration and I should mainly adjust speed at this point?
Found a Temp tower model with temps working properly. I used Generic ABS Defaults with my calibrated flow rate value (0.9576 fro 0.95, fairly inconsequential I would guess). Got horrible results again. Any suggestions?
No I haven’t dried it. I didn’t think ABS was that prone to water absorption, I only opened it a month ago but it has rained a fair bit where I am so I suppose its not off the table. I haven’t invested in a filament dryer yet. I’ve tried a bunch of different speeds in the slicer and they haven’t seemed to make any difference so you’re probably correct. Thanks for your help !
Those towers were not placed in the oven after being printed ?
The look over cooked - badly overcooked.
In fact so bad that I suspect the temp is not the actual issue here.
Check the lowest temp you can still get a good layer bond with - use that as the final temp for the tower.
For the lowest part use a temp 30 degrees above this value - e.g: 220 for the top, 250 for the bottom.
Use the standard ABS print profile but increase the cooling for overhangs and tick the box to slow down for overhangs.
After the fist layer is done click the speed button for the silent mode.
The tower should now print very slow and even slower for those overhangs and fine details.
Don’t worry too much about the bridges yet.
If things still come out ugly you won’t find the right temp.
Means you should try another flow ratio calibration.
Preferably with just a 3mm tall standard cube and 5 or so solid top layers - make sure there is at least one sparse infill layer.
Start with a low value and go up until those gaps between the infill lines go away but not so high that you end with big teeth on the outer wall.
I usually do this in 0.12mm layers using the quality profile.
Once done do both k-factor calibrations and find the best looking line/corner.
You want the value for the line that is fully even or the corner that is gap free without bulging.
The k-factor affects the acceleration calculations and through that the pressure advance - vital for going around sharp corners or corners for overhangs.
Once those two are properly calibrated and with the half found temps from before you should be able to print a decent looking temp tower.
Keep in mind that ABS loves to warp and curl up!
For these towers it is best to use a lower speed and more cooling - which can give false results as your normal prints will do faster.
Use lightning infill and print TWO towers at once with some distance between them - gives a much longer layer time and better layer cooling.
I think most of your troubles are due to speed, looking at the pictures the parts that have printed don’t appear to have the signs of water. It also looks like the temperature wants to be between 245-260 as if you look at the numbers this is where they are getting the best formation.
Aid you look closely at the print are there tiny little holes on the surface everywhere? I couldn’t see these in the pictures.
What I think is happening is that your bridge speed is way too high and the corner overhangs are being treated as bridges by the slicer causing the printer to speed up on these overhangs. I also think all your speeds need to come down in general for a start point.
Try changing all your wall and infill speeds to 70mm/s, top surface 50mm/s, bring overhangs down to 40mm/s for 10%, 30mm/s for 25%, 20mm/s for 50% and keep 10mm/s for 75% set bridges to 10-15mm/s.
In the filament settings under cooling tab change min print speed to 10mm/s rather than the 20mm/s it’s set to as standard.
Could you please also post a picture of your cooling settings?
Thank you for your help with this. I dried it in the P1S for 24hrs and got much better results though still far from perfect so I believe it must have been at least a bit wet. A lot of the other issues I think can be reduced to layer times. I watched a few bridges live and saw it bridge perfectly until a bit of filament let go and make a blob in the middle of the bridge which would interrupt the rest of the passes. Pretty content with this for now but if you guys did have any further suggestions lmk.
!
