Problems modifying .stl files for printer parts
 
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MrMik
(@mrmik)
Honorable Member
Problems modifying .stl files for printer parts

I'm trying to make some modifications to the extruder body, so that a Bowden attachment can be screwed into the body right where the filaments enters it. It's part of a moisture management system, see photo.

Using OpenScad, I'm running into problems when rendering the imported file
import("/media/..ENTER LOCATION HERE...../prusai3_mk2_stl/extruder-body.stl");

The extruder-body.stl file imports just fine and can be rotated and translated around, but as soon as I add in my little improvement, the rendering fails.

Previewing works, see photo below for illustration of what I'm trying to do.

When rendering, I get this error message:
ERROR: CGAL error in CGALUtils::applyBinaryOperator union: CGAL ERROR: assertion violation! Expr: target(s1).vertex()==target(s2).vertex() File: /usr/include/CGAL/Nef_3/SNC_FM_decorator.h Line: 224

Here is the OpenScad code if you want to have a play with it:

$fn=150;
difference(){

color("blue")
translate([17.5,-15,-47])
cylinder(h=5, r=5);

color("red")
translate([17.5,-15,-47])
cylinder(h=5, r=2.9);
}
rotate([90,0,0])
import(" Insert File location here /prusai3_mk2_stl/extruder-body.stl");

My questions:
1) How do I get around this without much hassle?
2) Are the printer part files available as .scad files as well as .stl files?
3) How do you modify printer parts without having to redesign them from scratch?

Cheers, Mik

Napsal : 22/10/2016 1:45 am
ayourk
(@ayourk)
Reputable Member
Re: Problems modifying .stl files for printer parts

Personally when I've wanted to edit these STL files, I import them into TinkerCAD and modify them from there. Granted, OpenSCAD should work just as well. I have had problems with the generated OpenSCAD STL files before. Maybe you should check into different versions of OpenSCAD that may perform better if you don't want to try TinkerCAD.

Dimensions PNG

and an 8 inch (200mm) or greater caliper is recommended.

Napsal : 22/10/2016 3:50 am
MrMik
(@mrmik)
Honorable Member
Topic starter answered:
Re: Problems modifying .stl files for printer parts

Thanks, Ayourk!

I find it very difficult to move parts to exactly where I want them in the Tinkercad software, but it solved my problem nevertheless.

After uploading the extruder-body.stl file to Tinkercad, and them downloading it again, the error does no longer occur.
Whatever is wrong with the original .stl file, Tinkercad seems to fix it, and then it works in OpenScad as it should have in the first place.
🙂

Napsal : 22/10/2016 6:43 am
shawn.t
(@shawn-t)
New Member
Re: Problems modifying .stl files for printer parts

To answer your second question, the SCAD files are available on the github repository here: https://github.com/prusa3d/Orignal-Prusa-i3/tree/MK2/Printed-Parts

NOTE: The above link points to the MK2 branch of the repository. The master branch is still the original Prusa i3 so if you are browsing around just make sure you switch to the MK2 branch!

Napsal : 22/10/2016 9:57 am
MrMik
(@mrmik)
Honorable Member
Topic starter answered:
Re: Problems modifying .stl files for printer parts

To answer your second question, the SCAD files are available on the github repository here: https://github.com/prusa3d/Orignal-Prusa-i3/tree/MK2/Printed-Parts

NOTE: The above link points to the MK2 branch of the repository. The master branch is still the original Prusa i3 so if you are browsing around just make sure you switch to the MK2 branch!

Thanks Shawn, most helpful!

I managed to print a new extruder body with Bowen adapter, from Taulman T-Glase, and it all seems to fit so far.

Napsal : 22/10/2016 2:10 pm
ayourk
(@ayourk)
Reputable Member
Re: Problems modifying .stl files for printer parts

Thanks, Ayourk!

I find it very difficult to move parts to exactly where I want them in the Tinkercad software, but it solved my problem nevertheless.

After uploading the extruder-body.stl file to Tinkercad, and them downloading it again, the error does no longer occur.
Whatever is wrong with the original .stl file, Tinkercad seems to fix it, and then it works in OpenScad as it should have in the first place.
🙂

The way I place parts EXACTLY where I want them is put down a ruler and modify the hard dimensions once I select an object. You get 2 decimals resolution.

Dimensions PNG

and an 8 inch (200mm) or greater caliper is recommended.

Napsal : 22/10/2016 4:08 pm
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