2D Pocket of circle adds linear movement resulting in non-circular circle

[brent2XUZQ]

I am running a 2d Pocket using a circle created with the circle tool.  The simulation does not show the slight flat spot on the outer edge that the G1 linear movement creates.

What setting could cause the 2D pocket tool path to add a linear movement and not make the circle perfect?  besides this linear movement the circle is very nice.  You can see the linear movement on line 69 and 93 as two examples in the middle of the circle.

[seth.madore]

Could you share the Fusion file that is associated with this part?
File > Export > Save to local folder, return to thread and attach the .f3d file in your reply

[brent2XUZQ]

Absolutely.  I think you are helping me on two threads now :-).  Oops

I am focused on setup 1 toolpath 2D Pocket1 (2)

[seth.madore]

Let's stick to this one thread and keep it contained 🙂

[seth.madore]

I think you're seeing those movements because of a couple things:

1) Your Max Staydown is quite lengthy at 2", so it's going to make a linear move to its next position when it's inside the "cup". If we reduce that to .5" it will make a small arc out, Z move up, position over and then proceed for the next depth

2) You have lead-in/out turned off. Thus, when it completes the circle, it's going to retract in the Z, all the while your tool is rubbing against the material

[brent2XUZQ]

Still tweaking the settings and haven't got it to be a good enough looking circle.  I haven't forgotten about this @seth.madore 

[seth.madore]

Can you export and share your latest version?
File > Export > Save to local folder, return to thread and attach the .f3d file in your reply

[brent2XUZQ]

Here is latest file.  I named the tool path in question for you "Look here Seth".  Also attaching pictures I just took on the machine from this toolpath.  You can see the linear move in question in the middle of the circle not at the beginning or end.

[seth.madore]

What post processor are you using?

[brent2XUZQ]

Mach3Mill

[seth.madore]

I'm not seeing the issue in the code, it's performing a complete circle at the end:

X2.5 I0.15 J0.
X2. I-0.25 J0.
X2.7 I0.35 J0.
X1.8 I-0.45 J0.
X2.9 I0.55 J0.
X1.6 I-0.65 J0.
X3.1 I0.75 J0.
X1.4 I-0.85 J0.
X3.125 I0.8625 J0.
X1.375 I-0.875 J0.
X3.125 I0.875 J0.
X3.1235 Y4.767 Z-0.3905 I-0.0985 J0.
X3.1193 Y4.783 Z-0.3861 I-0.097 J-0.017
X3.1129 Y4.7972 Z-0.3788 I-0.0928 J-0.033
X3.1053 Y4.809 Z-0.369 I-0.0864 J-0.0472
X3.0975 Y4.8183 Z-0.3568 I-0.0788 J-0.059
G1 X3.094 Y4.8217 Z-0.3498
X3.0903 Y4.825 Z-0.3428
X3.0846 Y4.8295 Z-0.3272
X3.081 Y4.832 Z-0.3106
X3.0797 Y4.8329 Z-0.2935

The last bit where it hits the G1 is all lead-out and it's moving in 3 axis. You can improve on that by having a zero Vertical radius, and then it will just be an XY move.

I'll also add that it's possible you're asking too much of your tool and machine. It looks like you're machining hardwood? What's your machine? A stepover of .20 might be too much for it to handle and it's flexing the machine/tool when it's cutting.

[brent2XUZQ]

This is a fair critique and I will try improving my settings to account for the material and my machine specs.

I am running a Maverick 4x8 CNC with a 3hp spindle and a 1/4" roughing bit from IDC woodworking.

I really appreciate you spending so much time helping me learn.

[seth.madore · Accepted solution]

Well, knowing that about your machine, I'm less inclined now to suspect that about your issue.

Yes, it's a hefty cut, but it doesn't appear to me that your machine is a "wet noodle" of a machine, it appears to be built rather stout.

However, to rule out issues, I'd start by lightening the load a bit, and leave more for a finish pass. Also, for your finish pass, have it take a "Repeat Finish Pass". I'd also try increasing the Lead-in/out sweep angle to 90 degrees of arc and only having a small vertical radius