I need help controlling supports in my design
 
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mchahn
(@mchahn)
Active Member
I need help controlling supports in my design

I have nut traps that are oriented such that the bolt comes in from the top.  This is a view from below that shows the square recessed area the square nut goes in. 

I need to restrict the supports so that none go into the inside of the trap.   In other words I just want it on the lip around the trap.  The bridging doesn't need to be good and I know it works without supports. I do this in simplify3d.

The only way I've figured out how to do this is to make a tiny brush and carefully go around the lip.  This is not practical because there are a number of these traps and it takes forever.  I've tried clipping the view from the bottom so that the lip is red and then painting the interior with a blocking brush.  (bottom view).

But this removes the support from the lips also.  (top view)

Can someone give me hints on how to get what I want?

 

Posted : 26/07/2021 5:51 pm
bobstro
(@bobstro)
Illustrious Member
RE: A couple of options

I'm understanding the top trap shown in the 2nd picture is the problem area. Do you have Print Settings->Support material->Options for support material and raft->Don't support bridges enabled? I'd expect that underside inside the trap to show as bridging, so that option should prevent support from reaching in there. Thoughts in no particular order:

  • A 0.25mm contact Z distance, 75% XY separation, and 3-4 interface layers makes removable support much easier to remove.
  • If this is your part design, you can design in support -- perhaps 45 degree angled supports off the wall -- to support the traps. A bit of sacrificial support consisting of thin, easily snapped-off supports might ease the entire process and reduce the need for the slicer to add supports.

Save your current  3MF project file, zip it up, and attach it to a reply here so we can see your part & settings and give better recommendations. It helps to be able to see everything in the slicer.

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 26/07/2021 8:08 pm
JoanTabb
(@joantabb)
Moderator
Nuts!

those nut trap tops are likely to droop without support
have a look at the attached project file, 
there are three example nut traps. 
the middle one is similar to yours 
the left one has a 0.2mm layer across the bottom of the hole, to aid with bridging
the right hand one has a modified top to aid with bridging. 

the middle and right hand have got support blockers to prevent support flooding the nut traps but allow support for other features if you need it. 
regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 26/07/2021 8:10 pm
Ringarn67
(@ringarn67)
Reputable Member

@joantabb

Project File Missing

 
Prusa I3 MK3S+ (kit dec -20), PrusaSlicer, Fusion 360, Windows 10...
Posted : 26/07/2021 8:49 pm
JoanTabb
(@joantabb)
Moderator
RE: Oooops!

Try Again
nutbox

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 26/07/2021 9:16 pm
bobstro liked
mchahn
(@mchahn)
Active Member
Topic starter answered:
RE: reply

>Don't support bridges

It was already set.  It must not be considered a bridge.  I looked in settings (advanced) and couldn't find where to set the definition of a bridge, like max length, width, etc.  I'm a pslicer newbie.

> nut trap tops are likely to droop

I've sliced this in simplify3d and printed it.  Yes there were some loose loops of filament but that didnt matter since the nut was screwed down tight. 

> attached project file

It looks like the project file is missing.  Speaking of which, how do I attach a project file in this forum?  I hovered over the buttons and none mentioned a file.

BTW, I was mistaken.  Blocking supports with a small brush doesn't work either.  Maybe pslicer isn't capable of just supporting the lips?

This post was modified 2 months ago by mchahn
Posted : 26/07/2021 9:35 pm
mchahn
(@mchahn)
Active Member
Topic starter answered:
problem understanding contents of project

I apologize in advance for my newbieness. 

When I slice the project I don't see any supports at all. 

I understand the extra layer in the left trap but I don't understand how it would block supports.  Is that layer easy to remove?  I might be able to just screw right through it with the bolt.

Are the right two ghost boxes the support blockers?  I've never heard of them.  How do you add them?  Would they also block supports for the lips?  My design has the traps up in the air with the holes facing down.  The traps needs support on the lips.

I don' see any difference between the right two traps.  What did you modify in the right one?

Another BTW.  I just got my pruser printer today and I admit I haven't tried printing the design yet.  Maybe the supports will come out of the nut trap easily.  When I had supports going up into the trap printed on my crappy creality printers they did not come out easily.  I had to use dental tools to scrape out the insides.  I tried a lot of different support designs in my slicer before I gave up and removed the supports from inside the traps.

 

Posted : 26/07/2021 9:58 pm
Swiss_Cheese
(@swiss_cheese)
Noble Member
Manual Supports

@mchahn

 

Have you considered modeling the supports in manually in your 3d modeling program of choice, and then just blocking that area with a "shape support blocker" e.g. a box assigned to block supports?

 

Regards

 

Swiss_Cheese

The Filament Whisperer...
Posted : 26/07/2021 10:07 pm
mchahn
(@mchahn)
Active Member
Topic starter answered:
reply

@joantabb, I see the difference in the two right blocks now.  Those extra layers are interesting.  Once again I don't see how that helps blocking supports.

@Swiss_Cheese, I'm reluctant to add supports to the designs.  I have dozens of parts and I can't just copy the trap supports.

Also, now that I've learned about support blocker boxes I tried adding one filling the interior of the nut trap. 

It didn't do anything though.  I'm getting convinced pslicer just refuses to block supports in this type of design feature.  I've specified blocking in several different ways that seem to me should work but it always slices to the same thing.  Maybe the inside of the trap is too small and pslicer just ignores it.

Posted : 26/07/2021 10:47 pm
mchahn
(@mchahn)
Active Member
Topic starter answered:
reply

@joantabb, I see the difference in the two right blocks now.  Those extra layers are interesting.  Once again I don't see how that helps blocking supports.

@Swiss_Cheese, I'm reluctant to add supports to the designs.  I have dozens of parts and I can't just copy the trap supports.

Also, now that I've learned about support blocker boxes I tried adding one filling the interior of the nut trap. 

It didn't do anything though.  I'm getting convinced pslicer just refuses to block supports in this type of design feature.  I've specified blocking in several different ways that seem to me should work but it always slices to the same thing.  Maybe the inside of the trap is too small and pslicer just ignores it.

Posted : 26/07/2021 10:48 pm
bobstro
(@bobstro)
Illustrious Member
RE: For complex parts, modeling in sacrificial supports in 3D CAD software is easiest
Posted by: @mchahn

[...] When I slice the project I don't see any supports at all. 

You do need to enable them (Print Settings->Support Material->Support material->Auto generated supports & Generate support material).

I understand the extra layer in the left trap but I don't understand how it would block supports.  Is that layer easy to remove?  I might be able to just screw right through it with the bolt.

That's an example of sacrificial support. It prints cleanly as a bridge and it's easy to knock the layer out. Otherwise, printed circles in mid-air are hard to support.

[...] Another BTW.  I just got my pruser printer today and I admit I haven't tried printing the design yet.  Maybe the supports will come out of the nut trap easily.  When I had supports going up into the trap printed on my crappy creality printers they did not come out easily.  I had to use dental tools to scrape out the insides.  I tried a lot of different support designs in my slicer before I gave up and removed the supports from inside the traps.

I have a little 20mm test part with an opening and hole that's very similar to your print. Using the settings I suggested above, supports come out very cleanly. Here's an example with PETG on my Mk3:

The modeled in "sacrificial support"approach Joan suggests will make the holes cleaner. Just add in a very thin layer in your 3D modeling program. You can even put in a very small gap at parts to help it pop out. Just model a thin layer across the opening. I use 0.2mm often.

You'll still need supports for the solid section of the trap that juts out. Again, you can model these with a chamfer-like angle on the underside. Think along the lines of a shelf support that you snap off after printing. This gives you a lot more control than using automatically generated supports. Angus has a great video on sacrificial supports on his Maker's Muse YouTube channel. Assuming you're modeling your own parts in a 3D CAD program, of course! (please confirm)

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 26/07/2021 11:00 pm
Ringarn67
(@ringarn67)
Reputable Member
RE: I need help controlling supports in my design

@mchahn

Speaking of which, how do I attach a project file in this forum?  I hovered over the buttons and none mentioned a file.

You have to ZIP the project file, forum does not allow 3mf
Under the text box it says "Attach file:" and a button "Choose File", choose file and hit save 

 

I apologize in advance for my newbieness. 

No need to, we have all started from scratch 😊 

 

When I slice the project I don't see any supports at all. 

Simple reason, there is no support in that file 👍 

 

I understand the extra layer in the left trap but I don't understand how it would block supports.  Is that layer easy to remove?  I might be able to just screw right through it with the bolt.

It stops support because the box "Don't support bridges" in "Print Settings"- "Support material" is ticked. You need to be in "Advanced" or "Expert", (top right corner) to see it.
Yes, it is easy to remove. Yes, just push through it, if you go from the bottom up you may have to start with a smaller bolt

 

Are the right two ghost boxes the support blockers?  I've never heard of them.  How do you add them?

Yes, they are support blockers. Select the object, right click, "Add Support Blocker" choose which one, drag and resize it to correct place and size. Done!

 

Would they also block supports for the lips?  My design has the traps up in the air with the holes facing down.  The traps needs support on the lips.

Don't know, upload your project file so someone can take a look at it

 

I don' see any difference between the right two traps.  What did you modify in the right one?

If you look from underside, drag the "ghost" box aside, the surface is not flat, it is several small surfaces. This will force PrusaSlicer (PS) to bridge smaller parts of the surface instead of whole surface, if you compare the middle one and the right one in preview window you see the different way PS handle it

 

Another BTW.  I just got my pruser printer today and I admit I haven't tried printing the design yet.  Maybe the supports will come out of the nut trap easily.  When I had supports going up into the trap printed on my crappy creality printers they did not come out easily.  I had to use dental tools to scrape out the insides.  I tried a lot of different support designs in my slicer before I gave up and removed the supports from inside the traps.

There are so many things that affects how easy it is to remove support. My experience with support is very limited so I am the wrong guy to support 😀 you with that. I have printed parts where support almost fell off by itself, PLA, and supports that I have to grind and chisel out

 

Hope some of it helped

Good Luck

Prusa I3 MK3S+ (kit dec -20), PrusaSlicer, Fusion 360, Windows 10...
Posted : 26/07/2021 11:01 pm
mchahn
(@mchahn)
Active Member
Topic starter answered:
thanks for now

I am happy to find that the community here is so helpful.  I have been given a lot to try so I'm off to do that.  If nothing works for my purposes I'll be back here with project in hand for more help.

Posted : 26/07/2021 11:29 pm
mchahn
(@mchahn)
Active Member
Topic starter answered:
resolution

For the curious and lurkers:  I solved my problem nicely using several suggestions from above.  The Makers Muse video on printing without supports was a major help.  I used sacrifical layers, angled support brackets (like shelf brackets), and simple designed-in supports.  I'm printing with no auto-generated supports at all ...

Makers Muse showed how to put in a thin (.75mm) wall to allow bridging on free-hanging features.  I had to add a foot on the base because of printing problems.

Posted : 28/07/2021 8:52 pm
Ringarn67 and bobstro liked
Swiss_Cheese
(@swiss_cheese)
Noble Member

@mchahn

 

Nicely done.

 

Swiss_Cheese

The Filament Whisperer...
Posted : 28/07/2021 8:58 pm
bobstro
(@bobstro)
Illustrious Member
Results look very clean
Posted by: @mchahn

For the curious and lurkers:  I solved my problem nicely using several suggestions from above.  The Makers Muse video on printing without supports was a major help.  I used sacrifical layers, angled support brackets (like shelf brackets), and simple designed-in supports.  I'm printing with no auto-generated supports at all ...

Since incorporating these sorts of techniques, I've found my print times are also reduced due to the elimination of those elaborate support patterns. Please update with some pics of the results if you can!

 

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 28/07/2021 9:25 pm
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