I’m trying to print a box lid using Bambu PETG-CF. As the photo below shows, the walls of the lid are in good condition, but the top surface (which is the inside of the lid) is pockmarked.
What filament settings should I try to change in order to get a smooth surface?
Looking at the picture I think that it might be slightly under extruding when printing the inside as the print speed would be faster here. What volumetric speed do you have set in the filament settings and also what are your infill speed currently set to? Also have you run through the calibrations for the filament?
Max volumetric speed: 11.5
Sparse infill speed: 100 mm/s
Top surface speed: 150 mm/s
I have run through the standard Bambu Studio calibrations – Flow Rate and Flow Dynamics.
150mm/s is a little fast for top surface/long runs and PETG in general. I use 80 max top layer and outside walls for better quality. It’s also a cooling problem with doing the overhangs as its going too fast.
Genericuser beat me to it, yeh bring surface speed down try between 70-100mms, generally you want to run any surface you see slower as you will get a nicer finish. I would also suggest reducing your volumetric speed to around 10mm2.
As suggested, I lowered Top Surface Speed to 80 mm/s and Max Volumetric Speed to 10mm^3/s. But as you can see from this revised print, the result is the same.
Could it be that the filament is damp? I dried it two days ago at 65C for 6 hrs, and the first prints that day came out great. Then it sat in the AMS for 2 days. The AMS has several canisters of desicant, but perhaps not enough to keep the petg from absorbing moisture?
Edit: viewing the original (left) against the revised (right) print, seems that the revised is actually worse.
It could have got wet if it’s been left out in a humid environment, how do you store it when not in use? You could try to dry it again I would suggest weighing the spool before and after so that you know that it is getting dryer.
Also have you watched the print while printing? If so do you notice anything in the layers before the top layer
Ouch, that did not work that way it should have. Moisture definitely causes defects and I was amiss not to suggest that along with the speed adjustment. Having said that, two days in an AMS shouldn’t have changed the levels that much, I’d be inclined the believe the original drying session wasn’t enough. There is evidence with the latest PETGHF that it needs a heavy duty dry cycle initially, this may be a similar case and I’m curious whether the stuff Bambu is making hasn’t been sitting in a leaky container on the docks for several months haha.
