Cut a Curve from a series of points

Machines (Original/PRO) How To
1

I have a curve that I would like to be able to cut where I have the X and Y values. How can I setup my Onefinity to cut this curve? Would I have to manually create G-Code?

|x|y|

|-30|0.0000|
|-29|2.0978|
|-28|4.1244|
|-27|6.0800|
|-26|7.9644|
|-25|9.7778|
|-24|11.5200|
|-23|13.1911|
|-22|14.7911|
|-21|16.3200|
|-20|17.7778|
|-19|19.1644|
|-18|20.4800|
|-17|21.7244|
|-16|22.8978|
|-15|24.0000|
|-14|25.0311|
|-13|25.9911|
|-12|26.8800|
|-11|27.6978|
|-10|28.4444|
|-9|29.1200|
|-8|29.7244|
|-7|30.2578|
|-6|30.7200|
|-5|31.1111|
|-4|31.4311|
|-3|31.6800|
|-2|31.8578|
|-1|31.9644|
|0|32.0000|
|1|31.9644|
|2|31.8578|
|3|31.6800|
|4|31.4311|
|5|31.1111|
|6|30.7200|
|7|30.2578|
|8|29.7244|
|9|29.1200|
|10|28.4444|
|11|27.6978|
|12|26.8800|
|13|25.9911|
|14|25.0311|
|15|24.0000|
|16|22.8978|
|17|21.7244|
|18|20.4800|
|19|19.1644|
|20|17.7778|
|21|16.3200|
|22|14.7911|
|23|13.1911|
|24|11.5200|
|25|9.7778|
|26|7.9644|
|27|6.0800|
|28|4.1244|
|29|2.0978|
|30|0.0000|

2

Are these points all coincident on an arc with one radius or are you looking to draw an approximated arc through them or more of a Bezier spline?

3

Hey Derek,

a parabola. @rich.ingle’s data look this way:

rich.ingle_data
rich.ingle_data570Ă—570 1.85 KB 

sed 's/|/ /g' rich.ingle_data_raw.txt >rich.ingle_data.txt
graph -T PNG <rich.ingle_data.txt >rich.ingle_data.png

rich.ingle_data_pure
rich.ingle_data_pure570Ă—570 912 Bytes 

graph -T PNG -g 0 -C -m -3 -S 4 <rich.ingle_data.txt >rich.ingle_data_pure.png
1 Like
4

Hey rich.ingle,

of course you could make a G-code script directly with these data, but it is far more easier, especially for sizing and accomodating to your workpiece, to use a CAD/CAM software for this. First you transform your data into a graphic (like shown above), then you import it into a CAD/CAM program, then you edit the size and whatever you want it to have as properties, and then you export the toolpath with a postprocessor for Onefinity (or a generic grbl). Et voilĂ !

1 Like
5

Thanks for the advice. I am new to the CNC game so am trying to do what you suggested. I created the graph in excel. I am only trying to create the curve for the 2nd half of the arch so from x=0 to x=30.

I took a pic of the graph in excel. I then created a jpeg in preview. I imported that into Carbide create. As you can see it ends up tracing around the curve so I have really two paths. I also tried creating an SVG file with the same result.

Here is a pic.

image

Any thoughts? I really appreciate the detailed help!!!

In Excel

image
image1070Ă—440 3.93 KB

6

Hey Rich,

I don’t know what you have done after importing. Do you want to mill a groove with the shape of the curve into your workpiece, I assume? If yes, you will have to create a virtual model of the workpiece and then a pocket with the desired shape in it.

I have never worked with Carbide Create, but I know they have a forum. Perhaps the exact way to create the virtual model can better be answered there.

1 Like
7

What CAD software are you using? I can see this being a use case that I would have frequently, where I want to cut along a curve in order to create a template to cut something else out using other tools.

I want the CNC to run directly along the curve. Right now, using the software I have it would basically cut around it as the software “traces” the curve.

Thanks for the all the help!

Rich