getting octagons, not circles

[Anonymous]

All of my designs with any arcs or circles are being segmented when it gets to the CNC machine. The machine can do circles, as I tested it with text and the “o” was perfect. Am I missing a setting somewhere?

[seth.madore]

Well, we don't know what machine or controller you are using, how the parts are drawn, or what post processor you are using. Need more info 🙂

Are you seeing this in a simulator at the machine, or in actuality?

[Anonymous]

I’m running a Millright Carve King, using Universal Gcode Sender, drawing with arcs and circles in sketch and then extruding (is that what you mean?) and seeing the segments in actuality. The design doesn’t look segmented and it simulates curved, it just mills segmented. It does the same thing (segments the arcs and circles) when I import a .dxf as well. I guess I was hoping there was an option in Fusion like in AutoCAD to choose the number of segments.

[seth.madore]

No, nothing like that in Fusion. Although, Fusion doesn't handle .dxf files well (regarding circles)

Can you share your file and the g-code? Toss them both into a .zip file and attach it here.

To get the fusion file: File > Export > Save to local folder. Return to thread and attach the .zip file

[Anonymous]

I am super sad to hear that Fusion doesn't like circles in .dxf files. Boo. I included a picture of the final cut out...I just let it go to see if everything else was doing what it was supposed to be doing. It seemed to be. Thanks Seth.

[seth.madore]

It's more that it's a gamble. Some .dxf files come in as spline curves and others come in as actual circles. 

Ok, what Post Processor are you using? Do you know if you have a max file size? Two options:

1) We eliminate all arcs and go straight point to point, very small moves. That may become a problem at higher speeds. It will also give us a much larger file size.

2) We try to go to radius moves instead of I/J/K's. That will be dependent on what post you are using.

[Anonymous]

The post processor is UniversalGcodeSender-v2.0.0-stable2...I think. You don't mean Brackets right? Haha...I'm so out of my depth here. I don't believe I have a max file size. Hmmm...I'll have to double check that. I seem to recall something about a max file size but that may have been in reference to NetBeans, which I ended up not using.

1) the point to point is something I could do in AutoCAD and import?  If it's anything complex Fusion runs really slow for me; I think it's the internet connection.

2) I don't know what I/J/K's are.

[seth.madore]

Ok, when you go to post the code inside of Fusion, what processor do you select from the drop down?

[Anonymous]

I go to Actions - Post Process and then grbl/grbl as a .nc file. Yes?

[Chetan.Bankar]

Hi @Anonymous,

It looks that your machine doesn't like the arcs to be output as I,J,K values. As mentioned by @seth.madore , this will need a Post modification such that to output the arcs as a Radius R value instead of I,J,K values, I believe. 

I hope this helps.

Thanks and Regards,

[seth.madore]

I do find it curious that there aren't more people knocking down this forum with similar issues. I assume there is a grbl/UGS centered forum that you can ask what other peoples experience is?

Before we go hacking up your post, I would suggest trying other posts that DO have the option for radius output. The Mach3 post might be a good place to start.

To answer one of your earlier questions about radius vs. IJK: Radii can be output in two fashions; either with a X/Y value and signed "R" command or with an X,Y and I/J value. For further reading, I'd suggest this article as a start

[Anonymous]

I, too, find it curious there isn't more on this topic. I searched high and low for a similar issue and found nothing...hence my post here. I have this same thread going on the Millright forum; we'll see what they have to say about it. I will look into your suggestions Seth and do some reading...oh joy.

Thanks Chetan and Seth.