vaiable extrusion widts and infill percentages
Hello everyone!
I'm trying to design variably soft interfaces for prosthetic and orthotic users and am stuck. I'm working with tpu/tpe and am tying to create squishy foam like devices with varying squishiness in Prusa slicer. I've had some success with gyroid infill and using stacked modifiers with variable infill densities to give different levels of squish. This works well but looks messy with the different densities stacked on top of each other and would possibly be a tear risk where a 20% infill is layed on top of a 5% making the connection weaker.
I've been trying to achieve the same effect by varying extrusion widt instead with a standard infill density across the model but using varying extrusion widt modifiers to add more stiffness in places.
The issue I'm having is when I then go to slice it, it looks like the extrusion widt modifier has changed the infill density in those areas too.
Is extrusion widt and infill density linked in some way?
Is it possible to vary extrusion widt across a model with consistent infill pattern?
Any help would be greatly appreciated!
Best Answer by Snuffleupagus:
@cillian-duffy
I noticed that PrusaSlicer would hold, but not re-display fractional input values in the "Fill density:" field of the modifier. I thought this might be confusing, so I made a newer example, and wrote the field input info into the modifier description, in hopes of better communicating.
Once again, it's best viewed after slicing using the Width view from the legend. If you hide all the feature types but Internal infill, Slic3r will display the difference with the highest contrast.
Defined Fill density example_Snuff.Zip
You can change the Infill type of the example to your liking, I used Grid because it best shows the alignment.
Regards
RE: vaiable extrusion widts and infill percentages
@cillian-duffy
Is extrusion widt and infill density linked in some way?
No.
Is it possible to vary extrusion widt across a model with consistent infill pattern?
Yes.
I have no project file to look at, however, It sounds like you may have some modifiers active that you might not be aware of, possibly you applied them at an earlier time and have lost track of them?
You should be able to easily change Perimeter and External perimeter widths using modifiers, and by default this will not effect infill percentage or infill extrusion width. You would have to add those settings manually, there are however several areas in the Slic3r UI to do this and you may have changed something be accident.
Regards
RE: vaiable extrusion widts and infill percentages
Thanks for your advice!
After doing a test print, there were definite infill differences through the different extrusion modifiers but I'll open a fresh file and try again.
Are there any other ways in Prusa slicer to achieve variable density for tpu/tpe? I know programs like carbon, spherene and ntop are doing interesting stuff.
RE: vaiable extrusion widts and infill percentages
Is extrusion widt and infill density linked in some way?
Rather than density you're probably actually simply asking about infill patterns perfectly matching up in which case extrusion width absolutely messes with it. As shown here with left cube being default .45 widths and the right cube modified to double that resulting in it looking like half density. But if the lines are twice as thick and there are half as many lines then the whole cube's density is actually the same, yea?
Is it possible to vary extrusion widt across a model with consistent infill pattern?
Next step, double the infill and now you get what looks like the same infill pattern at twice the width.
Basically, you can do what you are asking but its gonna take some extra maths and effort on your end.
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RE: vaiable extrusion widts and infill percentages
@cillian-duffy
I believe I may have misunderstood your question. I thought at first you were asking about perimeter and external extrusion widths effecting internal fill and that answer would be "No" However after reading this again I realized you were talking about changing the extrusion width of the Internal fill, and that answer is "Yes".
Changing the extrusion width of internal fill changes the density of the fill volume. For example, if you create a cylinder in Slic3r with a fill density of 20% (Default). Then add a modifier to the center of that cylinder with an "Infill" Extrusion Width property changed to 0.6mm, that would change the fill density by Approx. 7.35%.
So you could to keep it simple add 20 + 7.35= 27.35% and add a fill density property to that same modifier set to 27.35 and they would match.
I'm including an example file since that is probably the best way to promote understanding, this is easily done also.
You can best view the result by selecting the width view from the legend after slicing.
Fill density example_Snuff.Zip
Regards
RE: vaiable extrusion widts and infill percentages
@cillian-duffy
I noticed that PrusaSlicer would hold, but not re-display fractional input values in the "Fill density:" field of the modifier. I thought this might be confusing, so I made a newer example, and wrote the field input info into the modifier description, in hopes of better communicating.
Once again, it's best viewed after slicing using the Width view from the legend. If you hide all the feature types but Internal infill, Slic3r will display the difference with the highest contrast.
Defined Fill density example_Snuff.Zip
You can change the Infill type of the example to your liking, I used Grid because it best shows the alignment.
Regards
RE: vaiable extrusion widts and infill percentages
Thank you so much! I did a test print and this is exactly what I was after. It's an absolute game changer! I'm hoping to print some end use parts using the technique soon so I'll pass on any learnings. Thanks again!