Sanity Check on Supports  

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benjamin.r8
(@benjamin-r8)
Eminent Member

Hi, I've got several years of experience with 3d printing.  However, I've always had bad experiences with designs that require supports.

However, I see many designs shared that require supports and nobody ever mentions them.  A lot of the designs could be re-done to not require the supports as well.

Am I unique in my bad experiences with supports? 

I have used an older Makerbot (at the office) and I have an MK3.  I have used PLA and most recently tried PETG.  I have tried using default settings, and I have tried fiddling with them myself.  I have tried Simplify 3D.  My experience with supports is that they turn a design into a very low chance of a successful print for me (using FDM) without a significant amount of extra effort and failures.

I appreciate honest answers and I hope I don't come off as trying to start some sort of flame war.

If anyone reading this doesn't mind, another question:  Is multimaterial with a dissolvable support material a magic bullet for support issues?  Just looking for personal experiences from users in the Prusa family.  Just looking for a nudge to see whether it is worth pursuing.

Thank you!

Posted : 07/07/2020 6:13 pm
Neophyl
(@neophyl)
Noble Member

I try and design my own stuff to use no or minimal supports, mainly as the surfaces they support never look as good as when printed without.  However I wouldn't say that when I do use supports that it risks the print failing.  The supports that prusa slicer produces have a zig zag layer on the bottom which cant be turned off (although you can make it solid in Super Slicer).  Many seem to have problems with them not adhering at the direction change, but that just means their bed isnt clean enough (at least with pla).  When its fully clean the zig zag pattern will have no problems with peeling up.  I think that is one reason people have trouble with supports.  

What is a problem is the defaults that Prusa Slicer uses for contact distance, 0.1mm.  If you use that then you will have difficultly removing the supports.  Setting it to 0.2 or 0.25 results in them being MUCH easier to remove.  Also using about 3-4 interface layers also makes that easier.

The auto support algorithm is also very excessive which is why its better to use support enforcers sparingly to support only those areas that absolutely require it.  Fortunately the devs do know that it needs work so its on the road map.

I think that using the preview is vital and I am always surprised by how many people do not use it at all, looking through not only the normal colour coded layers but also switching to the other views like volumetric or speed views to see any other potential problem areas before even printing.

Cant help with the multi material or soluble support as I don't have a MMU.

Posted : 07/07/2020 6:57 pm
louis.j liked
benjamin.r8
(@benjamin-r8)
Eminent Member

Thank you for sharing your knowledge.  I will give those settings a shot.  

I too have experiences with the auto-support generator not hitting the mark.

As you say about the preview, my most recent project definitely wasn't going to work and I caught it during the preview.  Rotating the pattern helped me with that.  

Well now I need to decide if I'm going to keep scraping at my most recent print with supports or start over 🙂

I have tried doing my own supports before.  I basically built a solid part where the support structure would be, and made the contact areas with at the bottom and top (it was a "window-like" case) into very small dimples.  Triangles touching each other at the interface, I think.  It was ok.  I should have documented what I did.

I guess I need a couple of things:

1) a test case to print with different support settings (preferably quick)

2) a standard operating procedure for importing, modifying, and exporting existing files (because I keep learning and then forgetting certain steps)

3) documentation of my procedures and results.

Thanks again.

Posted : 07/07/2020 8:11 pm
louis.j
(@louis-j)
Trusted Member

@benjamin-r8

I also do not like supports and try to not use them when I design objects.

When I find something that I like and it needs supports I use PrusaSlicer to split the object and then place it so it can be printed without supports. I then glue it together using Goop. This is also sold as 'shoe goo' - it has a good shelf life and does not require much clamping - just a rubber band. It also drys slowly so you have time to get the right position. Final hardness is in about 2-4 hours. I find it is an ideal adhesive for plastic and it is cheap.

...
Posted : 07/07/2020 11:17 pm
Neophyl
(@neophyl)
Noble Member

One tip for cutting the object in Prusa Slicer.  If you place 2 or more cylinder shaped modifiers inside the object where you want locating pins to be then set them to 0 infill, 0 perimeters and THEN cut the object, the modifiers will be duplicated for each part and you will have perfectly lined up locating holes to help align the parts when gluing them together.  

Posted : 08/07/2020 7:08 am
louis.j liked
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