G02/G03: no circle/segmented circle with just one command

BobCAD-CAM Software Discussions
#1

Hi everybody,

I fail to get G-Code that mills full/large segmented circles with just one G02/G03 command. All PPs (coming with BC) I tried so far divide (segmented) circles in two G02/G03 commands.

Note: for small segments (I do not know for the smallest angle) BC just uses one operation.

%
O0100
(POST - BC_3X_MILL 3-AXIS GENERIC FANUC)
N01 G00 G17 G40 G49 G54 G80 G21 G90
(FIRST CUT - FIRST TOOL)
N02 T6 M06
N03 G54
N04 G90 X200. Y-220. M05
N05 G43 H6 D6 Z25.
N06 Z5.
N07 Z3.
N08 G01 Z-10. F1000.
N09 G03 X-200. I-200. J0.
N10 X200. I200. J0.
N11 G00 Z5.
N12 Z25.
N13 M05
N14 G90
N15 T6 M06
N16 M30
%

If the circle segment is also big enough (I do not know, at which angel this occur), a split will also be done.

Why? How to fix this? Played around with 319./320./321. … without success.

Thx, Harald

#2

Hi Harald,

BobCAD breaks arcs into smaller segments when an arc’s sweep angle is 360 degrees (or bigger for helical arcs). For an arc with a sweep angle less than 360 degrees, BobCAD should be able to output it in a single G02/G03 command line. You just need to make sure post-processor questions 221 and 223 are set to “n”.

P.S. If arcs are output with Radius instead of IJK, the post-processor question 221 should always ve set to “y”. Visit our Help System for more info.

#3

Hello Mo,

  1. and 223. both set to “n”.
    Circle with 259° is one G2/G3 statement. 259.9° already splits into two operations (I have not tried to find out when the break occurs).

Is there a reason, why BC-CAM split below 360° and not >360°? I can only assume that a full round of 360° is not enough getting a good result and a larger circle has to be split anyway.

Bye, Harald