100 sided circles

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DeanR181
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100 sided circles

Post by DeanR181 » Thu Feb 05, 2015 2:31 am

Hi all, hope someone can help. I am printing large circular objects on my UP 3D printer and what is happening now is the round outer and inner surfaces are actually being made up of 100 (approx) flats sides. It is not printing proper smooth round surfaces but has many small flat faces. I have calibrated the printer but cannot overcome it. The printer seems to be running smoothly on its slides but just not printing perfect round objects. Any suggestions would be welcome.
Thanks, Dean

mb20music
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Re: 100 sided circles

Post by mb20music » Thu Feb 05, 2015 3:00 am

Can you post the .stl file?

DeanR181
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Re: 100 sided circles

Post by DeanR181 » Thu Feb 05, 2015 7:21 am

Thanks for the reply. I have found out by accident what the problem is. When I saved the file as an .stl file from Solidworks, the "tolerance" was very low, so I decreased the tolerance which created a bigger file and with no flats "triangles". I have just finished printing the new part and it looks perfect.
Thanks again
Dean

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DrewPetitclerc
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Re: 100 sided circles

Post by DrewPetitclerc » Thu Feb 05, 2015 7:50 am

A little teaching here, an "STL" file when looked at in any type of viewer, you will see that all surfaces are made from small triangles, hence the "Tessellation" in "STL", and you will notice that all cylinders walls are made of narrow flat planes each made of................2 triangles!

The CAD or Modeling program you use to create the solid will make these surfaces look smooth but in truth they are not.
It is all about the "Resolution" you choose when generating the "STL" from your model, higher resolution more triangles, smoother looking prints, but never completely smooth as even at the highest resolutions the surfaces will still be made up of tiny triangles, also higher resolution means larger file size and significantly longer slicing and coding for print.

Sorry if I sound preachy, late night, bad day at the office.

Regards
Drew
Drew Petitclerc
Petitclerc Designs
Owner/Senior Principal Designer, prototype, tooling and test equipment design and 3D printing
http://flash-graphics.deviantart.com/
http://www.thingiverse.com/DrewPetitclerc

DeanR181
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Joined: Wed Feb 04, 2015 3:13 am

Re: 100 sided circles

Post by DeanR181 » Thu Feb 05, 2015 8:58 am

Hi Drew, Thanks for the detailed explanation. This is exactly what my problem was and after converting from Solidworks to stl file with a much higher resolution (decrease in tolerance in Solidworks) the parts now come out perfect.
Thanks Again
Regards
Dean

mb20music
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Re: 100 sided circles

Post by mb20music » Thu Feb 05, 2015 11:32 pm

Glad you figured out the cause of the issue.

I also want to mention that printing round objects in 'fast" mode can have a similar effect that you described.

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DrewPetitclerc
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Re: 100 sided circles

Post by DrewPetitclerc » Fri Feb 06, 2015 4:50 am

mb20music wrote:I also want to mention that printing round objects in 'fast" mode can have a similar effect that you described.
Fast mode only accentuates the sharp cornering as the extruder is moving faster and thus tends to "bump" around these corners.

None of the setting in the "UP" software will do anything to increase or decrease the faceting of the model, only a CAD or Modeling software in which you can selectively increase or decrease this resolution has any effect.

Regards
Drew
Drew Petitclerc
Petitclerc Designs
Owner/Senior Principal Designer, prototype, tooling and test equipment design and 3D printing
http://flash-graphics.deviantart.com/
http://www.thingiverse.com/DrewPetitclerc

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