3D printed parts are angular instead of rounded?

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ethannino

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Hey everyone,

I'm working on a coupler section for my rocket made of 3d printed ABS plastic coated with epoxy resin. The 3D printer I have access to uses dxf files and converts them to gcode (I think?), and the result is that round objects like circles and splines have a blocky, angular surface. I used Solidworks to make the model, and I'm pretty sure that's the cause of the low print quality. Something similar happens when I try and laser cut dxf files made in solidworks, like it converts splines and circles into low resolution polylines. Anyone know how to fix this?

I know for a fact the 3d printer is perfectly capable of printing smooth curves.
 
Hey everyone,

I'm working on a coupler section for my rocket made of 3d printed ABS plastic coated with epoxy resin. The 3D printer I have access to uses dxf files and converts them to gcode (I think?), and the result is that round objects like circles and splines have a blocky, angular surface. I used Solidworks to make the model, and I'm pretty sure that's the cause of the low print quality. Something similar happens when I try and laser cut dxf files made in solidworks, like it converts splines and circles into low resolution polylines. Anyone know how to fix this?

I know for a fact the 3d printer is perfectly capable of printing smooth curves.

What 3D printer? What slicer are you using?

Can you export the model into an STL file and use that? Also, do you have a picture of the printed part?
 
It's a TAZ lulzbot 5 (I think it's a 5, might be a 4). Come to think of it, I think it does use STL files, and the slicer we use is 'slic3r'.

I don't have a picture of the printed part, it looks cylindrical but instead of perfectly round it's like a 30-40 sided polygon.
 
I think your STL settings need to be tweaked. Look for a chord and angle setting....set them to zero and 1 respectively. Thats what I set them at for Pro Engineer, but my Solidworks by default has had nice resolution on the STL at our default settings...
 
When you save the .stl file, select options, set resolution to custom, and under angle set it to 2deg.

If you set it too small the file will be huge and take forever to slice...
 
When you save the .stl file, select options, set resolution to custom, and under angle set it to 2deg.

If you set it too small the file will be huge and take forever to slice...

If he is using Slic3r the slicing process shouldn't take but a minute or two.

I used to use Slic3r and its great for freeware. However, I recently switched to Simplify3D. So I would check your settings for .stl files and if that doesn't work or if you have questions about Slic3r hit me up.
 
From my experience, it is your rendering software at fault, not the slicer. I use OpenSCAD for rendering my models and all rounded objects (cylinders, spheres, toroids, etc) are built from a series of flat surfaces. The more surfaces used, the smoother the object is. You can use this to your advantage, since you can create a cylinder and set the number of surfaces to six and the result will be a hexagonal cross section (perfect for bolt heads, nuts and holes to fit either one). You really want to slice your object from an STL file, and it is your rendering software that makes that. The slicer just makes the gcode that tells the printer where to move the head and when to squirt plastic - and that gcode is built from whatever the stl file going in looks like.

So, the more surfaces (or facets) that a round shape has, the smoother the object. Downside is that it takes a lot longer to render an object with a lot of facets. So the level you choose is a compromise between quality and render time. Although I haven't confirmed this, my guess also is that an stl file with a higher number of facets is probably larger than one with fewer facets. And larger stl files will probably mean longer slicing times.

You might also try other slicing programs - I use Cura. It is easy to use and does a good job. Slic3r sometime gives me somewhat wonky gcode. Plus, since it is the recommended slicer for my printer (Deezmaker Bukito), the manufacturer provided printer profiles for that program that sets up the gcode with all the commands needed to start the print job (heat head to proper temp, initialize head, etc) and the shut down code, and includes those codes in the final gcode file.

Hope this info is useful.
 
that angle setting in the stl options in solidworks makes a big difference. here are two files, one with the default 10 degrees setting and then 2 degrees. I saved them out as stl then read them back into solidworks...note the number of triangles!

STLPart_2deg.jpg

STLPart_2deg_size.jpg

STLPart_10deg.jpg

STLPart_10deg_size.jpg
 
That did the trick!

Thanks for the help, it was indeed in the STL settings in Solidworks.
 
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