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Help on arch geometry, PLA

Posted: Tue Jun 05, 2018 11:37 pm
by Timon
Hello everybody,

I am trying to do the geometry which you can see below. I want to have a nice surface on the upper side of the lip, which is why I am printing it this way. However, this way, I have an arch like geometry and the printer does not seem to cope with it too well.
I am printing with a white, 1.75mm, PLA filament. I have tried different temperatures (205°C, 215°C, 235°C), and printed with support material (same PLA filament as above), as well as without... the result stays rather crapy either way. I am currently using a 0.03mm layer hight and a 0.5mm extrusion width (0.4mm Nozzle, but a wall thickness on the sleeve of 1mm, so I wanted to have 2 layers instead of 2.5). The bead is at 60°C as suggested for PLA by the ideaMaker PLA template. Besides of the aforementioned parameters nothing has changed compared to the original PLA template.
I have thought about changing the retraction settings next. Neither do I know if this is going to be the key to my issue, nor how to exactly change them in order to get better results.
If anybody has an idea about what to change in order to get rid of the messy edge of the rim/lip, and/or the riffled surface on the backside of the sleeve, please let me know.

Cheers,
Timon

Re: Help on arch geometry, PLA

Posted: Wed Jun 06, 2018 12:42 am
by Jetguy
Please see this exact topic, because your problem is related- poor overhang performance is in the same reasons for layers on raft or support sticking too much. viewtopic.php?f=8&p=32218#p32218

Simple fix?
Print more than one object at a time to increase total layer time, thus giving the layer time to cool before a hot layer is applied on top. This greatly improves overhang performance.

This is also basically what the simplify 3D print quality guide says as well.
https://www.simplify3d.com/support/prin ... eshooting/
Specifically https://www.simplify3d.com/support/prin ... verheating

Re: Help on arch geometry, PLA

Posted: Wed Jun 06, 2018 11:29 pm
by Timon
Thank you Jetgun! This was a really promising idea. Unfortunately my print still does not come out any better than before. I printed at 215 degrees Celsius - relatively low.
Generally: Do I necessarily need to print the structure next to my main structure? If I have a dual extruder, I could just leave the second one empty and "print" the second (support) object with this one - even though it is cold and empty. This way I could save some filament and still give the filament on my main part time to cool down and settle. ... or is there any misconception in this?

Re: Help on arch geometry, PLA

Posted: Thu Aug 23, 2018 2:41 am
by robpauza
Another thing you could try is to simply slow down your print speed. Mine stays at 45mm/s and seems to be very accurate.