Help needed with a tall thin object that has minimal contact with the print bed.
 
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Help needed with a tall thin object that has minimal contact with the print bed.  

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david.j49
(@david-j49)
Eminent Member
Help needed with a tall thin object that has minimal contact with the print bed.

Hi, I need some help with printing the Valve Index Controller Grip Cover

So far I've only printed my own designs and I always made sure they had sufficient surface area contacting the  bed, I've never printed a model that basically doesn't touch the bed at all. 

I'm not sure what's the best orientation. I can't lay it down on the front to keep the outer surface clean and I have a feeling that if I lay it on its back, the hexagons will give me some trouble. I'm inclined to keep it upright because that would produce the nicest surface finish, but I'm afraid that it will be too wobbly and will either break off at some point or at the very least will develop layer shifts near the top as a result of the bed moving back and forth. 

How would you go about printing this on a Prusa? 

Also, last night I decided to give the default orientation and default supports a go to see what would go wrong. It did go wrong, but not in the way I expected. 

The second layer of supports completely failed to attach to the first layer. I've printed with supports many times and this has never happened to me. Any idea what caused this and how to fix it? 

Printer: MK3S

Material: Prusament orange PETG

3MF attached. 

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This topic was modified před 5 years by david.j49
Napsal : 10/09/2019 10:01 am
JBinFL
(@jbinfl)
Reputable Member
RE: Help needed with a tall thin object that has minimal contact with the print bed.

David:

Saw your post last night and i sliced a test object to print to see how it comes out.  Not the full object but up to z height 25 so as not to waste filament.  It is printing now and seems OK, I increased brim and used a support modifier.   I will post more today after work on what i did with pictures to see if it helps you.

Strange women, laying in ponds, distributing swords, is hardly a basis for a system of governance!

Napsal : 13/09/2019 2:56 pm
rmm200
(@rmm200)
Noble Member
RE: Help needed with a tall thin object that has minimal contact with the print bed.

You might also try tree supports in Cura.

As far as I can tell, Prusa Slicer (Beta) only offers tree supports with the SL1.

Napsal : 13/09/2019 3:04 pm
david.j49
(@david-j49)
Eminent Member
Topic starter answered:
RE: Help needed with a tall thin object that has minimal contact with the print bed.

Hey guys, thanks for the tips. 

The problem pictured above went away on its own after an automatic config update a few days ago. I guess one of my config files got corrupted somehow. 

As for my fears of excessive wobble, the print didn't break off, but the surface was very much not optimal, especially near the top. 

I tried reducing the jerk value in plicer to half and that gave me a near-perfect surface finish. I'll probably end up using that one. For the second one (you need two—one for each controller) I was going to reduce jerk even further, but I might try tree supports. If I put in extra supports to brace the model against the Y axis movement, that should help, right? 

Napsal : 13/09/2019 3:35 pm
JBinFL
(@jbinfl)
Reputable Member
RE: Help needed with a tall thin object that has minimal contact with the print bed.

OK,  here is my test.  I used a brim with 10 width to ensure the support and print bases touched to ensure adhesion.  I added cylinder supports to the two arms since they had a pretty large overhang and used support for the bottom area since it had a small contact surface.  I used support enforcers for all .  It was only printed to a z height of 20 since I did not want to waste filament on something that i did not know what it was for 😀

PETG is petty sticky, so i printed at 85% speed at first and then went to 100% once the base was done, Prusament PETG scrap was used.  No problems with adhesion.  I think a wide brim and support at the bottom is needed given the architecture of the print.  That orientation is hard to print and get a nice finish otherwise.

My test supports are probably too wide, so if you do the same you can reduce them in size.  I added the 3mf file from Prusa Slicer as well as some pictures.  The part where it touches the supports is probably the most unpretty areas, so that should be minimized, but it works and you can adjust to get it as pretty as needed.  I thought the supports were needed for two reasons, 1 to provide a nice stable base on the heatbed surface so that once it got up in height it would be less likely to detach and 2 since it would suck to have a 5 hr print fail near the top, better safe than sorry..

Hope that helps.  And I am sure others could do more with other software, but that was what I would do...

 
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Strange women, laying in ponds, distributing swords, is hardly a basis for a system of governance!

Napsal : 13/09/2019 9:57 pm
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