Support column fails on 5" high print
I'm trying to print a hollow tube that is pointed at the top. The top ends in a blunt tip so I need a support at the top. Basically the support ends up being a column that is less than an inch in diameter and over 5 inches high. This causes the column to be unstable after it gets over 3 inches high. It wiggles which causes an issue with the filament sticking to it. I'm printing PETG at 235 F. So far I've tried organic and grid/rectilinear supports. The organic separated at about 2" which caused a failed print. The grid held together in a mess but the filament stuck enough to allow the print to finish. I managed to print the part I needed but I was just curious as to how others would deal with this.
RE: Support column fails on 5" high print
Usually I use brim for something like a column which is wobbling, but that won't help if it's the support column that is the problem.
You might also be able to change the model to avoid the need for support by adding a 45% chamfer inside if this works for your application. Like this (modified on the left, original on the right):
RE: Support column fails on 5" high print
Thanks for the reply. Yes, I thought of doing that as a last resort. Since I got the project printed it's not a big issue now but I thought I would ask what people would do to change the support column. I guess there might be a way to anchor the column using supports to the interior of the object. I might try to see if there is a way to paint supports in Prusa slicer to accomplish that. I haven't tried painting supports yet.
RE: Support column fails on 5" high print
The equivalent of a brim for supports is called support first layer expansion. Do a settings search if you don’t know where it is, also make sure you are in expert mode so you can find all the settings.
RE: Support column fails on 5" high print
Thanks I see that. It's set to 3.5mm. I'll keep that in mind. The thing is the support did not come off the bed. The issue I believe is the support the slicer generated is like a square column and when it gets over a few inches it starts to flex.
RE:
You write: I'm printing PETG at 235 F. In the civilised part of the world 235F would be known as 113C. Too low for printing, so is that your bed temperature (maybe too high then) or is it a typo?
Otherwise, for PETG use a satin sheet, well cleaned.
RE: Support column fails on 5" high print
That's a good suggestion but I'm using a Satin sheet that was cleaned with soap and water and then alcohol. The actual issue is that the column is so high it's not stable. The bottom support is not coming loose.
RE:
Then maybe just model the supports in a way that gives more stiffness. .
RE: Support column fails on 5" high print
Model a tower inside the tube up to 4.5 inches, allow for supports not on the base plate and it should create short supports from the tower to centre of the tube.
RE: Support column fails on 5" high print
Alternatively consider splitting the tube and top. Say your tube wall thickness is 10mm, model it to 20mm from the top then thin the wall to 5mm. Model the top with the same outside diameter on top of a tube with 5mm walls 20mm tall. print both and you can fit the top over the Main bit of tube. You might have a just visible join line or it might disappear into the layer lines. You will need to change the 5mm down slightly to allow for extrusion but you can experiment with tubes 5mm tall to figure out the exact sizes.
You can adjust this idea to have the wall on the top fit inside instead of outside, so that the visible join is closer to the top and obviously the sizes are just for illustration. A few dabs of CA glue will hold the two parts together
RE: Support column fails on 5" high print
I like your last 2 ideas. Next time I print one I'll give them a try!