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pipaev
Posts: 22
Joined: Thu Dec 24, 2015 7:17 am
Location: Russia, Moscow, Zelenograd, skype: pipaev

Re: Slicer behavior for thin walled sections

Fri Feb 05, 2016 12:53 am

pixel3design wrote:2. You are right, but as you know as mechanical designer, you can't drill a 2mm hole with a 10mm drill bit. Live with it.
Exactly that's why I can't tune extrusion width for 1mm thick wall with 0.36mm printing width.
Why I should "live with it" if a solution is more then possible?
If you'll look around you will see that all human made things and all nature created things are based on compromises. That's the way of evolution.
When you make anything you should use tricks especially when programming something.
My idea for this 1mm thick wall, for example, to build outer 0.34mm width perimeter which will give 0.68mm of thickness and then make second 0.32mm width perimeter for "forward move" with idle "backward move" of extruder. (Also idle "backward move" could be used to make extrusion width wall thickness.) The result width will be 1.00mm. Do you think that it's not possible to print 0.32-0.34mm width using 0.3mm nozzle?
P.S. Sorry for my English. Greetings from Russia!

rafiki270
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Re: Slicer behavior for thin walled sections

Mon Feb 08, 2016 6:15 am

+1 on thin walls ... for people who are not printing mechanical components this would be amazing

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AK_Eric
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Re: Slicer behavior for thin walled sections

Tue Feb 09, 2016 12:33 am

I've +1 this repeatedly before, and I'll do it again. Thin walls should be printed with a single extrusion, if the (non-existent) option allows it.

I've been printing with volcano nozzles, from .6->1.2mm. It's extremely frustrating that S3D will leave huge gaping holes in walls of the resultant gcode because it's slightly narrower than the nozzle with. Insert the rage meme of your choice here.

As silly as it sounds, I've recently been commissioned to print some cat armor from thingiverse for a friend. But since some of the walls are narrower than the .6mm nozzle I'm using (forget using anything larger, like the 1.2 I have currently installed), big voids appear in the walls of it. Now I'm having to hack my profile (as mentioned earlier in this post) with artificially smaller nozzle diameters and jump through all the troubleshooting hoops that ensue to compensate for it... or just tell the guy I "can't do it", when the machine easily could.

If s3d would just print a single layer in there, all would be well. Put all the warnings on that checkbox you want, I'm prepared for the consequences.

Please s3d devs, implement this feature.
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MHC
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Re: Slicer behavior for thin walled sections

Tue Feb 09, 2016 6:23 am

I've just been hit by this issue/problem/user confusion. I've read this thread, plus others, and despite some excellent explanations I remain confused. Hoping someone can correct my thinking.

I created a box (using Fusion360) with walls 0.4mm thick, floor 0.9mm. The walls do not appear in the preview.

My settings (Wanhao Duplicator 4S):

Extruder tab
  • Nozzle Diameter 0.4mm
  • Extrusion Multiplier 0.90
  • Extrusion Width (Manual) 0.4mm
Layer tab
  • Primary layer height 0.3mm
  • Bottom solid layers 3
  • Outline/Perimeter shells 1
  • Outline Direction Inside-Out
Infill tab
  • Infill percentage 0
Since my desired extrusion width equals my model's wall thickness I'm confused as to why S3D doesn't want to print the walls.

Ways to get the walls to appear in preview:
  1. Reduce extrusion width from 0.40mm to 0.39mm
  2. Rotate model 45 degress around Z axis on print bed. Am not suggesting this is a suitable "fix", only highlighting it in case it leads to any ideas on causes.
Can someone please explain what's happening? My aim is reproducible dimensional accuracy (within FFF tolerances, of course).

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pipaev
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Location: Russia, Moscow, Zelenograd, skype: pipaev

Re: Slicer behavior for thin walled sections

Tue Feb 09, 2016 6:50 am

I experienced such issue with the empty box wall thickness equal to the extrusion width when there are appeared 2 sides of 4 with one corner in the preview window. This is one of S3D "features". Changing extrusion width helps but it's not a solution.
P.S. Sorry for my English. Greetings from Russia!

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dkightley
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Re: Slicer behavior for thin walled sections

Tue Feb 09, 2016 8:28 am

I've just been hit by this issue/problem/user confusion. I've read this thread, plus others, and despite some excellent explanations I remain confused. Hoping someone can correct my thinking.
Very briefly......

The way the FFF printing method works is that the nozzle extrudes a strip of plastic that is either the same thickness as the nozzle diameter, or is a little wider, depending on the extruder software settings. It is impossible to lay down a narrower strip.

Most slicer software packages will extrude this minimum width for where the width of the designed wall is less than the extrusion width. Simplify3D differs in that it stops the extrusion whenever the wall width is less than the extruded width. The visual effect of this is that the users see that the slicer has missed out thin walled parts of the model. This will be visible on the preview, but some users don't spot the omission until after printing.

The suggested enhancement is to provide the user with an option to either allow extrusion of the now "too wide" bits of the model, or to continue as the slicer is behaving at present, and don't extrude...but to display a warning that there are missing bits.
Doug Kightley
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Railway modeller and webmaster at http://www.talkingtgauge.net

MHC
Posts: 12
Joined: Fri Jan 15, 2016 5:33 pm

Re: Slicer behavior for thin walled sections

Tue Feb 09, 2016 12:03 pm

Doug,

Thanks, but...
Most slicer software packages will extrude this minimum width for where the width of the designed wall is less than the extrusion width. Simplify3D differs in that it stops the extrusion whenever the wall width is less than the extruded width.
The highlighted part is what confuses me in this instance. The model wall is 0.4mm, the nozzle width is 0.4mm and the extrusion width is also 0.4mm. Thus I expected it to print a single perimeter wall.

What am I missing?

Regards,

Mark

natty15d
Posts: 7
Joined: Mon Feb 29, 2016 5:17 am

Re: Slicer behavior for thin walled sections

Wed Mar 02, 2016 6:49 am

pipaev wrote:I experienced such issue with the empty box wall thickness equal to the extrusion width when there are appeared 2 sides of 4 with one corner in the preview window. This is one of S3D "features". Changing extrusion width helps but it's not a solution.
Had the exact same issue yesterday

zemlin
Posts: 333
Joined: Mon Feb 01, 2016 11:36 am

Re: Slicer behavior for thin walled sections

Thu Mar 03, 2016 12:32 pm

I can see both sides, for sure. As an engineer and a guy who is making parts that do things, accuracy is important to me and having material someplace I didn't plan on it could cause problems.

That said, a check box that says "Print something regardless of thin sections" would be useful when dimensional accuracy isn't the first priority.

I'll put my vote behind this one.

FlashErase
Posts: 17
Joined: Thu Mar 03, 2016 1:31 am

Re: Slicer behavior for thin walled sections

Fri Mar 04, 2016 12:54 am

+1
I agree with zemlin.

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