Bobcad V34 cutting arc in segments, not smooth. Why?

[wrustle]

I am machining an arc (64.0625" radius) on the end of an 8" wide plate. When posting the code for our Haas VF-2SS it is cutting it in segments, not a constant G2 radius from left to right.

The finish needless to say shows segmented cuts along the entire length.

Cannot for the life of me figure out why it is cutting a segmented arc and not smooth.

Below is the code from the subprogram for that tool and profile. Work, diameter and lengths offsets are in main not shown below.

Even if I just post only that entity, it still cuts it in segments.

(FIN PROFILE - PROFILE FINISH)

G00 X-0.4611 Y0.171
G01 Z-0.925 F90.
G41 X-0.3993 Y0.0924
G03 X-0.25 Y0.0836 I0.0786 J0.0618
G01 X-0.1567 Y0.1768
G02 X0.0045 Y0.2496 I0.1768 J-0.1768
G01 X0.6698 Y0.2875
X1.3354 Y0.3186
X2.0013 Y0.3427
X2.6674 Y0.36
X3.3337 Y0.3703
X4. Y0.3738
X4.6663 Y0.3703
X5.3326 Y0.36
X5.9987 Y0.3427
X6.6646 Y0.3186
X7.3302 Y0.2875
X7.9955 Y0.2496
G02 X8.1567 Y0.1768 I-0.0155 J-0.2495
G01 X8.25 Y0.0836
Y-5.7836
X8.0836 Y-5.95
X-0.0836
X-0.25 Y-5.7836
Y0.0836
G03 X-0.3618 Y0.1828 I-0.1 J0.
G40 G01 X-0.4611 Y0.171
G00 Z0.1

Later,
Russ

 

[gustafson]

I program G Code like I weld, which I stick stuff together and it mostly doesnt fall apart, but is it possible the post is not setup right, mebbee you never noticed if you didn't do a large radius?

 

[chineshop_guy]

believe your post is set set to break arcs into quadrants. sort of standard, not sure why.
check line 221 and 223 in your post processor. both should be set to no.
also, haas is notorious for leaving marks at quadrants anyway. especially older ones

 

[triumph406]

Maybe what you think is an arc is really a Nurb spline.

Or you can increase the curve tolerance (assuming Bobcad has that option) to minimize the length of the segments

 

[triumph406]

haas is notorious for leaving marks at quadrants anyway. especially older ones

Only if you don't have backlash comp correct. That could happen on any cnc if backlash comp is incorrect

 

[wrustle]

For anyone who may come upon this issue, I found out it is a setting in the post processor that needs to be adjusted.

The arc radius defaults to "60" in the post processor (line 319 for Haas) before breaking the arc into segments..

The radius I was trying to cut was 64.0625". Once I adjusted the setting to "65", all was right in the world!

Later,
Russ