Printing a Semi-Circular object - Ideas?

[Tetraodon]

Hmm - I have two semi-circular tubes which interlock (currently a prototype) and am trying to figure out the best way to print them to prevent using supports - because they are 15cm long (and some will be larger) I can't print them upright (which would be the obvious way to go). Admittedly figuring out the best way to print things economically (with as little support as possible) has stumped me a little. Any ideas for the best orientation?



The inner tube is attached if anyone wants to have a looksie.

[Tetraodon]

A second one to have a look at (ignore the logo printed on the bottom - it'd be on the side, Blender for some reason is giving me problems with it )

Breederbox.factory

(135.66 KiB) Downloaded 628 times

[JoeJ]

I would still print them upright, just do it in 2 sections. For example, print the bottom 10cm in one print and then the remaining 5cm in the next print. You're going to get a much better surface finish that way.

PS - in case you didn't know this trick, you can actually drop part of the model below the build platform if you don't want to print it. So combining that trick with the "stop printing at height" option will allow you to easily print the 2 sections I mentioned above

[Tetraodon]

I've been thinking about doing so but it means that I either need to use acetone to combine them (not my preference as these are products rather than one-off prints) or would have to design a second locking system to keep them together - I think I may have to go for the latter.

[KC_703]

I my be missing the mark here...

Print them both upright, with an ample brim (10-15 outlines) help stabilize the base. Make sure print island is on along with retraction of the nozzle on moves.

Then they both sides should snap together...(?) Because its taller, it will take a longer to print...

On perfectly circular arches, supports may not be needed... Make sure you have enough perimeter layers, and check printing "inside-out". I like a 1mm perimeter wall for strong projects, you'll need to do some math to get the number of perimeters according to your layer width; [(1mm / layer width)= #perimeters] (ie 1mm/.4 layer width = 2.5 perimeters). For an arch, a 1mm perimeter will actually produce more like a 1.1-1.2mm perimeter due to the way the filament will be laid down.

[Tetraodon]

Unfortunately they're a wee bit taller than what my printer will print - I intend on making ones larger also, as this is one of the smaller sizes - so I think I may have to work out a second interlocking system to print each part in two parts (making 4 parts total).

I'm tempted to try without supports but I've just had so little luck bridging/printing with overhangs lately I'm a little bit nervous to (as it looks like it'll be doing each perimeter the full 150mm in one line), although for some reason my overhang test was perfect, so I might try a miniature version to see how it goes.

[tonyno]

If it's not oval, it should work. That's been my experience.

[Rebekah_harper]

hmmm, interesting.

support a definate must. use a one layer seperation for the suppor and a distance from part 0.5mm

I would adjust the angle to cover only the middle 3rd. the density I would be in the region of 10% and have 3 or 4 dense layers at 80% ish.

I think the speed should be on the low side too especially for the grated part.

that's what comes to mind at this moment.

[KC_703]

Try a section of the arch as a test with no supports... Take the first 5mm. Could be surprising... and save a lot of headaches.

[Tetraodon]

We had a sudden case of weird print adhesion, but it's back to normal now and I could do a test print.

The lines in the middle are the remains of the supports - left of it had supports, the right had no supports. Supports were 5%, 5 dense layers of 15%, 0.35 horizontal offset from part, 1 upper and lower vertical separation layer.





So supports definitely aren't needed except for the top two angles

Unfortunately (something I've been experiencing with lots of prints) it's still pretty messy at one point - any thoughts on printing this cleaner? (file attached)