Need advice for a rare printing issue!
It’s printed in crystal abs at 250 C, the base of the pyramid is perfect, but the top part appears melted, it’s printed in a wallace based printer.
Thanks for any advice
Avoiding such tall shapes to melt is difficult without an extremely well calibrated printer+slicer. I have two ways to overcome that:
- Printing more than one of the same object, to keep the nozzle moving away regularly (and thus letting the plastic cool down)
- Particularly for pyramids, they give a much better result when printed resting one of the other sides (i.e. https://github.com/carlosgs/carlosgs-designs/tree/master/Pyramids-easy-to-print )
Good luck!
You can also set the minimum time for one layer in most slicers, you could try increasing this value.
Get a fan, turn on cooling in slicer.
Print a column next to the model the same height, giving the nozzle time to cool
@Vaclav_Hula fans can make ABS have poor layer adhesion, but could possibly be set to only come on for tiny layers, I can’t remember if slicers support this
Slic3r definitelly supports this.
Do not use a fan on ABS, you’ll get curling and warping. As others have mentioned slic3r has cooling settings, and you can also print a priming pillar to allow the layer to harden before printing. The priming pillar will work better because if your printer just waits, it’ll be dropping and will need priming. If it prints really slow on the previous layer, out still might not be cooled enough.
Thanks to all, at first i thought that my termistor was busted, but printing other things was ok, i’ll go with multiple objects/column print to let the layers cool down!
Also, with regards to printing tiny towers in ABS; If you wrap your heater block in some ceramic insulation like the qubd people do, you might be able to keep a bunch of radiant heat off the part. Like this: http://christopherpoole.github.io/static/images/qubd_extruder/wrapped.png
This isn’t something I know for sure will work, but it should…
@ThantiK looks just like mine, radiant heat soften the small area layers, i’ll try to find an issulation material to do the same
@Carlos_GS i’ll try this today
You can just sit there and blow on the top for the final tip layers. Not advisable on a regular basis for health reasons but it’s a quick and dirty one off. Printing an adjacent column is a better suggestion.
I turn the fan on with abs if the layer time is less than 15 seconds. It works great for prints like this.
Similar to @Clint_O_Connor , you can spray some canned air on those top layers.
But frankly, I’d say it’s the slicer using a different infill pattern for those smaller-area layers at the top of the pyramid.
The plastic needs the correct time to cool. A fan may work but it may also cause it to warp if cooled to quick. You need to slow down the top of your print. Some slicers will auto detect this and adjust, if not you may need to adjust the entire print. Can you print the 5mm calibration cube? It detects this issue at the top of the model.
A fan for abs is a bit of a risk, ABS needs to be pretty hot to bond well with the layer below and if that layer has been cooled the bond will be weak. If you have a very well directed airflow from your fan that only blows across the top of the print you can avoid warping due to uneven cooling.
I’d set a minimum layer time in your slicer, you can work out what it should be by timing the duration of one of the good layers a mm or so below the point where it gets melty.
@Ralph_Apgar I’m using the last version of Slic3r, will check on the calibration cube
@Tim_Rastall great idea to use the timing of a good layer, i’ll have to figure it out where to modify the Gcode in order to do that thanks!