Auto support generation appears to have a problem

[JohnSays]

I have a part that is essentially a cutout of a pipe. The inside of the pipe has purposeful extrusions and needs to be supported when printed. Automatic generation of support places 0 supports on the drawing. Trying to place them manually has been impossible. The tool won't even allow me to move a support under the top extrusion. I need to print in this orientation for strength. Although I have tried rotating it so the extrusions are rotated 90 degrees just to see if I could place a support. Isn't there some way to tell the support engine to support internal parts? That top extrusion is obviously not going to print.

My work-a-round is to redesign the part with a piece of plastic printed between the extrusions.

Front View

Top View

2016-08-07_14-33-26.jpg (14.82 KiB) Viewed 2999 times

I added the internal piece and tried the auto support again and got this (which I can now use). Note that the added piece is just 0.2mm x 0.2mm:

With temporary piece added

[CompoundCarl]

You most likely have a problem with the STL file. If the mesh has a lot of errors in it, you can have trouble getting the automatic support stuff to work. If you post your factory file here, others can help more.

Also, can't you just rotate it 90 degrees and print it without any supports at all?

[JohnSays]

Thank you CompoundCarl! I fixed the errors and the support generated perfectly. There were some "self intersecting surface" errors. I have another slicer called IdeaMaker and it has an auto-repair function. i used that for the repair although, interestingly, IdeaMaker does not report this type of error. I need to find out about that.

I need to print it like this for strength -- I think. I am also trying it turned 90 degrees and will test the strength difference when they are both printed.

I will try to remember about posting the factory file. That seems to be a really good way of communicating problems evidently.

Does my drawing get sent along with the factory file?

[dorsai3d]

Factory files include everything (profile, model, processes) except firmware definitions, but those rarely are customized. Strength of your part depends on how you're loading it, but it'd probably work well printed vertically with no supports. Doesn't look long enough that bending will come directly into play, and if you were to use it to connect things, bending would cause problems along the layer lines in either orientation. Pressure inside and outside would be handled best by the vertical orientation.

If all printing software reported STL errors, maybe people would start getting the idea that STL is a terrible file format, and most 3D modeling programs aren't very good at making solids.

[JohnSays]

Thank you