I build flange systems with the 3D printer. If you print a normal flange, then you always have to print cylindrical support structures around the whole tube. Printing these support structures is very time consuming. The material used is just waste. According to the slicer software, the overhang threshold alpha (max) 55°. For overhangs whose angle of inclination (90°=vertical) is above this threshold, no support material is generated. In other words, this value represents the largest horizontal slope (measured from the horizontal plane) that can be printed without support material.
In order to save support material, I considered the possibility of constructing ledges into the part. The required material for support structures is much lower and the required printing time should be much shorter. Especially with large and high parts (in Z-direction) you can save a lot of material and costs. I tried to construct the ledge using a small triangle. Revolution around the axis should then create the ridge. Unfortunately the function does not work. I do not know why? Can someone help me please?
For me, Revolve command works well on curves: Rhinoceros Help
Your idea is quite wise. But you can also do it differently:
design some 3d printed removable collar (printed separately) that you could mount when your printer will reach the top ring level (printer should stop there) and it will replace supports (you should stop printer on exact level with gcode stop command). Printed collar should have the same height as your empty space and it would replace supports (it may be mounted from two parts and screw together). It may be done if you will have to print many same items. It’s not worth do one or two pieces but when you need to print 30 then it`s ideal solution.
you can cut in the top (just below the ring) and print the top ring separately. It would be needed to glue it after.
You can cut in half to have two same parts which will be glued in the middle after printing both parts. Both parts would be printed where ring would lay on the bed. So there would be no supports at all.
You can design tree supports that will be dense near the top and spare in the bottom area.
This is only an idea. You may have 3d printed collar which you will mount to 3d print when you reach a certain level. The printer should stop there and wait until you will mount the collar on the print bed. After that, you may resume print and it will print on it the same as on the supports. There are few problems here. Height should be exact same space!!!. I think that is possible to do. Another thing that you should mount the collar without messing your print on the bed. The collar may be on screws or magnets.
There is also one way more.
5) You can change your design more into 3d printing world. The bottom is straight but the upper is on an angle (with small overhangs to not generate supports). Small overhang/bridges under 5mm may print well sometimes but those areas may be weaker. It’s an idea only also. Maybe it’s good maybe it`s bad. Maybe holes should be drilled after print and print those holes filled as bridges or without holes at all (to add them in the post stage).
