Unresolved Problem with Printing Dome-Shaped Objects

Any object I print that has a domed or round top always comes out looking like the photo. It comes out like this whether it has infill or not. It shouldn't need supports because the angle isn't that steep. The last object I printed (not this one) I gave it 4 solid top layers, and it didn't make any difference, though I'm not really sure what solid top layers means for curved objects.

 

Which material are you using and at which temperature do you print this?

 

The top. I've had issues printing anything round. A rounded bottom is messy for the first couple dozen layers, needing a good sanding to finish. The tops leave these holes, the bigger the object the worse it gets.


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PLA at 210. I get consistently good prints in the 195-210 range, but 210 seems to be the optimal temp.


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I try to print around 195 to 200 deg. the higher I go, the more I get such problem. On the other hand, the bigger the sphere gets, the bigger gets the overhang at the center.

 

Check out my previous post in another thread.
http://forums.robo3dprinter.com/index.php?threads/fingers-and-hands-for-children.4004/#post-35137

 

You need to set your infill to 25%
Or more.

If you are using a 0.4 sized nozzle, then your bottom!top layer should be a multiple of that, say 1.2
0.4 x 3 = 1.2

Use a raft and print it upside down.

I use 0.2046 resolution

 

This particular print was done with Simplify 3D. I also had the problem running MatterControl using, I think it's called MatterSlicer.

This print was an ornament with lithopane. No infill so I couldn't print upside down. Plus, as I said, I have problems with the bottom layers of an upcurve print. I'm sure some tweaking would fix that-but I don't know where to start. Supports maybe? A nose cone I'm trying to print also has to be hollow. The top wasn't as curved so it printed better, but still had a hole. I'm confused about the bottom/top layer formula example. I am using the 0.4 nozzle. What is the 1.2 and where does the 3 come from?

 

In Simplify3d can you set temperatures at different layers, I would try that and also if you could slow down the print speed at the top layer.