Incorrect cut size

[frogsplumbing]

Good morning,

I am new to CAD and am still learning how every thing works in Fusion so I have the hobby version for now.

I picked up that when I was cutting with the CNC using the adaptive clearing function i was a couple of millimetres out on the designs i was cutting. So on a friends advice and on his CNC I did a test using three basic circle’s each with a different diameter. The same tool and machine were used to cut using Fusion and another CAD program. When cutting the NC file from fusion I get a discrepancy of 2mm on the X & Y plane Z is correct, with the other CAD program the dimensions were correct. So don’t think it is a machine problem. (other CAD program is used often on the CNC with no problem)

As mentioned I'm still learning. What am I missing and how do I go about rectifying this problem?

The controller the CNC is using is a RichAuto A11 .

Kind Regards

Gareth

[leo.castellon]

Attach a file to get an informative answer, otherwise we are just guessing.

LeoC

[frogsplumbing]

Ok great, Thanks Leo

[programming2C78B]

That doesnt help us at all

My guess is your Wear comp is set differently in the 2 programs or you have Stock to Leave on.

Adaptive is not a finishing toolpath. 

[frogsplumbing]

What doesn't help?

Stock to leave was off.

I can except that, but then why is the Z axis cut correctly and only the X and Y axis's incorrect?

[a.laasW8M6T]

Because the Z doesn't move in the program(Dynamically)

As mentioned above Adaptive is a ROUGHING toolpath and is not suitable for finishing parts with, you should always use some stock to leave with adaptive and finish up with a 2D contour afterwards.

Adaptive makes a bunch of small line segments that approximate the contour and depending on your controller this can result in inaccuracies

2D contour should output true Circular moves and will likely result in a more accurate cut

[frogsplumbing]

Thanks Andrew,

Your explanation has helped me understand a little more👍 could I go straight to the 2D conturing?

If my friend was also using a roughing program for the test cut, why would his be accurate and mine not? Any ideas? 

[programming2C78B]

your file doesnt help at all. It shows no intended feature size or even a toolpath to calculate the cut size from. 


so many variables.....simple matter is adapt with ~.01" stock left, finish with 2D Contour. We can worry about any size issues if theyre still present. 

[frogsplumbing]

Sorry for the delay, are you wanting the file from manufacturing with in Fusion? The one I sent was just the NC code.

Will try the solutions above, thank you.

[programming2C78B]

Not necessarily, just a code that actually correlates to some sort of known dimension. Easiest is just do a 1" bore with a known tool size and look at the code. The result of the arc size + tool size should equate to 1".