Ringing and corner pull

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Calpoog
Posts: 17
Joined: Fri Sep 16, 2016 1:51 am

Ringing and corner pull

Post by Calpoog » Tue Sep 20, 2016 7:02 pm

Hey again everyone,

Another noob question here. I've read through another thread about corner ringing and it describes my issue exactly. The corners kind of bulge out in both directions on sharp corners. I read things to consider were reducing acceleration, adding small fillets, possible NEMA 17 dampers, and possibly orienting walls at 45 degree angles to the axis of travel. I'll be sure to consider these for my next print.

A more extreme problem is happening, though, and I think it is mainly due to how I am printing. I want to call it "extreme ringing". Basically it happens on corners that are also overhangs. Here's a textual example followed by a visual one:

Two sides of the pillar look like this:

Code: Select all

|  /
|_/
So the corner in question is one that is going out as an overhang in both the x and y directions. The issue being that there is lift at every pass. Visually that corner at every layer is raised as the extruder continues to touch it on each layer and re-heat it and pull it up as it moves by the corner. This leads to some seriously ugly corners and an obvious pattern as well as a not-very-sharp corner.

It's difficult to take a picture, but you can see in the V shaped groove on the right of the object that the south-east facing corners (particularly in the top-most V groove) is really goofy looking.

I'm assuming some of the fixes suggested above will assist with this and that there's no way to completely avoid it given I was doing 90 degree corners that are overhanging the previous layer on both sides. Any help would be great!

Thanks!
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jsc
Posts: 1864
Joined: Thu Apr 10, 2014 4:00 am

Re: Ringing and corner pull

Post by jsc » Fri Sep 23, 2016 3:42 am

That is a different issue entirely. What you're seeing is PLA curling (I'm assuming you're printing in PLA) in overhangs. This happens when the filament isn't cooled off fast enough, and is a common issue when printing with PLA.

First step is to make sure your bed fan is blowing 100% throughout your print, except for the first layer. If you're already doing that, the solution is MORE COOLING. I've solved the issue by replacing the bed fan with the most powerful fan I could source and designing a fan shroud for it. If you want a quick and easy solution, try pointing a desk fan at your print and see if that helps.

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