Top Horizontal Shell Problems
I'm sometimes having a problem with top horizontal shells. The layers won't lay flat, resulting in something that looks like bubbles or like rip-stripes (like a cat has swiped their claws through it). I've tried to search for other topics that deal with this, but I'm not really sure the best search terms to describe this.
I had similar things happening on the first layer and I was able to correct with z-height, but obviously that can't be the problem here.
What should I be looking at to fix? Horizontal shell speed?
-Mike Ogilvie
USA - Richmond, Virginia
RE: Top Horizontal Shell Problems
This looks like pillowing, caused by excessive heat/insufficient cooling and insufficient top layers. Ultimaker has a good guide on fixing this problem and All3DP has another. You've probably got cooling at 100% with PLA, so you might try :
- Reduce speeds for top solid infill.
- Reducing the printing temp (will help with stringing too).
- Add a top layer or two.
Simplify 3D has a nice print troubleshooting guide.
RE: Top Horizontal Shell Problems
@bobstro
Thanks. Looks like changing some cooling settings and maybe bringing down the nozzle temperature will be the things to try.
They also suggest increasing the number of top layers, but that would definitely not help in my case - would almost make it worse.
Hopefully the cooling or temp changes will help. I'll try to post an update later.
-Mike Ogilvie
USA - Richmond, Virginia
RE: Top Horizontal Shell Problems
[...] They also suggest increasing the number of top layers, but that would definitely not help in my case - would almost make it worse.
If the other measures don't work, give it a try. I was skeptical when this 1st happened to me, but I've since learned not to "save" on top layers. Good luck with it.
RE: Top Horizontal Shell Problems
@bobstro
I guess it couldn't hurt to try, but the rip/stripes are so severe and vertical that I can't imagine a way in which additional layers will do anything but make it worse.
After reading about pillowing from your links, I don't think my issue with the horizontal layers not adhering and lifting off are quite the same as pillowing. I haven't seen any pictures that look like what I have. But it does seem probable that at least the cooling and temperature issues might the cause.
-Mike Ogilvie
USA - Richmond, Virginia
RE: Top Horizontal Shell Problems
Not sure, but looking at how sparse the infill is, could it be as the top layer bridges are cooling, they are pulling together causing adjacent layers to buckle?.
Try a gyroid infill with maybe a higher infill %.
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