Printing ABS problems
Dear all,
My name is Brent, I am relatively new to 3D printing. Currently, I am trying to make something in ABS with my Prusa i3 mk3S. I already noticed that difficulties with ABS are hot topic on this forum. Sorry for again repeating the subject...
I am trying to make a part with an outer screw thread. I already succeeded with PLA (right picture, print is perfect) but it is not working out with ABS (left picture). I print ABS at 245°C and the print bed is heated until 85°C (with spray to enforce adhesion to print bed). These temperatures were recommended by the manufacturer of the filament.
I had a lot of problems with warping of the whole part. Another subject on this topic taught me to make an enclosure and this helped great. But still, I have trouble with making the screw thread. Adding support is also not the best solution (quality is better then no support but I get deformation of the screw thread, see picture below).
The whole print is OK but only the outer screw thread is always failing (and this is the most critical part of my print). I scrolled on this forum to similar questions. Some people are printing ABS with a cooling fan (at 20% to 50% speed) and others are avoiding any cooling with printing. I tried printing without any cooling (in slic3r) but even with disabling the fan (in filament settings), the hotend fan is still working... I don't know if disabling the hotend fan will increase my print quality (and I also don't know to turn this off). Could this be the problem of my failed prints? Should I turn on the cooling fan on low speed?
Or am I doing something wrong? Do you any solutions/hints for this problem?
All info are very appreciated as I am desperate...
Thank you very much!!
Best regards,
Brent
RE: Printing ABS problems
ABS needs more time to cool, without cooling fan.
But if a part is small, then it is not cooled down enough, and it warps with next layer.
2 things you can do,
1 . A little bit cooling, (to much cooling the part can be brittle, print higher temperture if needed)
2. Print more parts on bed, so the abs can cool down, before the next layer.
And every can be filament is different.
RE: Printing ABS problems
- ABS needs an enclosure to prevent warping
- Once you have an enclosure with hot air inside, you need the part cooling fan to avoid temperature artifacts (extruded filament not cooling fast enough) or super slow printing speeds. You can tweak that in the filament cooling presets. Don't forget to lower the minimum printing speeds.
- The hot-end cooling fan cannot and must not be switched off. You'd melt the plastic the extruder is made of.
RE: Printing ABS problems
You can change the slow down timer in Filament_Settings>>Cooling - it slows down printing when layers are small.. Default is 20 seconds; up this to a minute and see if it helps. Or, you can add an intra-layer delay using the customer gcode:
Add dwell to the Printer_Settings>>After Layer Change box:
;AFTER_LAYER_CHANGE
;[layer_z]
G4 S60
http://marlinfw.org/docs/gcode/G004.html