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Printing overhang with support

Posted: Fri Jul 08, 2016 1:15 pm
by DBFIU
Hello.

I am printing this model shown. It is being printed in a heated enclosure at 65C. The overhangs are looking like this, even with support. They just want to curl upward and that intereferes with the next layer. I thought the heated chamber should prevent this from happening as it slows the cooling process of the plastic thereby keeping the curling from happening?


Image

wall thickness about 0.125"

Print params:

speed - 100mm/s, 50% outline speed
print temp 230c
E3D hotend volcano with 0.6mm nozzle
heated chamber at 65c
layer width is 0.78mm
0.95 extrusion multiplier
0.25mm layer height
20% outline overlap
45% support density with 2 dense support layers at 70%, horizontal offset 0.40mm

I may try this with the heated chamber off.

Re: Printing overhang with support

Posted: Sat Jul 09, 2016 6:52 am
by andrewk72
Personally, I think it's actually the opposite. If the plastic stays hot longer, it can curl more. If you cool it rapidly, it's stuck in that position. That's why you tend to use a lot of cooling with PLA. If you try printing PLA without cooling, it will curl like crazy.

Re: Printing overhang with support

Posted: Sat Jul 09, 2016 9:12 am
by DBFIU
I am running a 65C heated chamber to print ABS.

I also thought it would be clear from the print params that it was ABS. Look at it this way, if its 230C PLA in a volcano E3D, I doubt youd get a good looking print :o

No one on gods earth would print PLA in a 65C heated chamber either unless you want a puddle of PLA on your build platform...

Sorry if I didnt specify, it is ABS. :mrgreen:

Re: Printing overhang with support

Posted: Sun Jul 10, 2016 5:13 am
by andrewk72
Yup, I already knew you were using ABS, I'm just telling you that too much heat and not enough cooling could easily cause the issues in your picture. I've seen it happens for ABS and PLA.

Re: Printing overhang with support

Posted: Wed Jul 13, 2016 2:24 pm
by DBFIU
Ahh I got you now.

So you think I should run a cooler chamber temp or a cooler nozzle temp? I dont want the part strength to be compromised.

Re: Printing overhang with support

Posted: Wed Jul 13, 2016 4:20 pm
by dorsai3d
The supports look like they're too far away from the overhang and aren't ever actually touching it to hold it down. Maybe you can try 0 vertical separation and enough horizontal separation that the support is just barely touching the outer perimeter of the layer above?