Small parts with eyelets won't print.
March 19, 2015 10:45AM
My Prusa i3 rework prints great larger parts, but it fails every time when it's thin tall part, especially if it has eyelet in it. I'm attaching such example (idler roller) and what it came out. Once it starts printing those thin columns print head just starts to push into material and move it sideways completely messing it up. I suspect it's speed issue in Slic3r, so I tried adjusting some parameters (i.e. Permieters speed to 20 mm/s) but so far had no luck. What other settings can I try? I print ABS at 225 C, heat bed is 95C first layer and 90 other layers

P.S. I managed to finally print this part by printing two at the same time at some distance from each other. I believe it gave ABS needed time to cool down. But which setting in Slic3r can do this? I don't want to do double prints every time smiling smiley

Edited 1 time(s). Last edit at 03/19/2015 11:09AM by Bratan.
Attachments:
open | download - idler.jpg (13 KB)
open | download - small_part_fail.jpg (8.7 KB)
Re: Small parts with eyelets won't print.
March 19, 2015 11:16AM
Hi,

For small areas it actually looks like you are printing too fast and laying new plastic on the still molten layers below.

I print ABS at 220C so the temperature sounds about right. I also impose a 5 second minimum layer time and turn on my cooling fan fully for layers with a print time of 5 seconds or less.

People say not to use a fan with ABS but for small features and low layer print times I have found it to be necessary.

Regards,
Neil Darlow


I try to write with consideration for all nationalities. Please let me know if something is unclear.
Printing with Mendel90 from fedora 25 using Cura, FreeCAD, MeshLab, OpenSCAD, Skeinforge and Slic3r tools.
Re: Small parts with eyelets won't print.
March 19, 2015 11:18AM
The problem is the small area of the layers. They don't have time to cool before the nozzle comes around and lays down the next layer of plastic on the still soft previous layer. You need to give it time to cool before printing the next layer. In Cura you can tell the slicer the minimum time per layer and if the layer finishes faster, it will move the nozzle away and wait, then resume the next layer. Slic3r doesn't seem to have this type of option (or my version is too old), so you can achieve to same result by giving the printer something else to print along with your part that will cause it to take longer between layers- have it print a cylinder- or maybe turn on skirt and have it print the skirt as high as the part itself. If you have other stuff that needs printing anyway, print the parts at the same time- be sure to pair this spindly little part with something bigger and taller so that your little part will get the extra time it needs all the way to the top layer.

That part design isn't particularly 3D printer friendly. I would try to eliminate unnecessary overhangs. The nice filleting of the overhangs is pretty to look at and great for injection molded parts, but not always best for 3D printing.
Re: Small parts with eyelets won't print.
March 19, 2015 11:42AM
i have just got mine to print abs pretty good now and have done some pretty different pcs, im sorry but are u using slic3r if u are maybe try and lay it flat, like rotate it 90 deg and then play with support material settings just a though if u want can u attach the stl maybe ill try printing it for fun

nick
Re: Small parts with eyelets won't print.
March 19, 2015 08:18PM
Instead of using a fan, print two of the same models on one plate and put them a few cm's away from each other. This allows the layer to cool on the first part while it puts a layer on the second part. Only workaround I found useful for ABS.

Don't print with a fan, warping is terrible with ABS.


http://www.marinusdebeer.nl/
Re: Small parts with eyelets won't print.
March 19, 2015 09:33PM
Thanks guys! It seems Slic3r does have similar issue, I found this on another forum "Filament Settings -> Cooling -> Slow down if layer print time is below: x seconds"
It's misleading, as it seems to be about cooling fan, but from what I read it actually just slows down printing process. I'm gonna try it tomorrow.
Re: Small parts with eyelets won't print.
March 19, 2015 10:15PM
Quote
Ohmarinus
Instead of using a fan, print two of the same models on one plate and put them a few cm's away from each other. This allows the layer to cool on the first part while it puts a layer on the second part. Only workaround I found useful for ABS.

Don't print with a fan, warping is terrible with ABS.
Yeah thats exactly what i did and it worked too, but took 2x more time to print
Re: Small parts with eyelets won't print.
March 20, 2015 05:41PM
Just a follow up. I can now confirm that slowdown/autocooling option in Slic3r really helps when printing small objects! I didn't have "Enable Auto Cooling" option checked, and I think that what's made huge difference. I think it enables other options on this page such as "Slow Down if layer print time is below". I set it to 5 seconds.
Here's screenshot (attached).
Attachments:
open | download - slicer_autocool.png (25.9 KB)
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