newbie problem cutting circle

[Trisdan]

I'm new to this, but tried to use the wizard for cut circle.
 When I try diameter 30 I get 56, on the display while cutting the numbers for X goes from  -12,8 to +38,  and for Y from -25,7 to +25,7.
This is quite frustrating, do anyone have an idea what I'm doing wrong?


The G code is :
F400
G00 Z10
G00 X12.9 Y0
G00 Z1
G01 Z-0.5 F50
G02 X12.9 Y0 I-12.9 J0 F400
G01 Z-1 F50
G02 X12.9 Y0 I-12.9 J0 F400
G01 Z-1.5 F50
G02 X12.9 Y0 I-12.9 J0 F400
G01 Z-2 F50
G02 X12.9 Y0 I-12.9 J0 F400
G01 Z-2.5 F50
G02 X12.9 Y0 I-12.9 J0 F400
G01 Z-2.9 F50
G02 X12.9 Y0 I-12.9 J0 F400
G00 Z10
G00 X13 Y0
G01 Z-2 F400
G01 Z-3 F50
G03 X13 Y0 I-13 J0 F400
G00 Z10
G00 X0 Y0
M30

[Tweakie.CNC]

Trisdan,

Your code is OK and the extents are + and - 13.0000 for both the X and Y axis (see pic)

Are your work offsets set to zero ??

Tweakie.

[Trisdan]

Thank you for help, but I don't manage to change it, it jumps back if I try to put in a new value.
 I tried to get around the problem by using a 8mm tool to get 60mm hole instead of 56mm , but now the awful machine make a hole of 120mm , and the program limits are now x -84 ,  + 28  and  y -56 ,  +56. Why do they jump around and make the hole anything but right?

[Overloaded]

Are you reading MACHINE coords., or PROGRAM/PART coords. ?

[Overloaded]

You also have to hit the ENTER key after a DRO entry in order to make it "stick".

[Trisdan]

In the Tool Path , the window  Program Limits    Absolute Coordinates , it looks like the picture from Tweakie but the values are all 0 before I load the wizard and after I loaded it the x range is -84.000  +28.000 and y range  is -56.000   +56.000  and I can not alter the values even if  I hit the ENTER key after entering new values.
 I tested in MDI mode setting x and y and z to zero and wrote   g-code in the INPUT line : G02 X0 Y0 I-27.9 J0 F100   and that made a nice circle of right dimension.  
Is something wrong in the Tool Path and I how can I correct it?

[Tweakie.CNC]

Hi Trisdan,

I think you need to set your work offsets to zero (then regen toolpath to see the changes) if you want the program limits to show just + and - 13 etc.

Tweakie.

[Trisdan]

Thank you for giving me good advices.
When I start Mach3 the values in Offsets (Alt-5)  menu are all 0 , but after moving the machine to where I want to have it as start point and in the Program Run (Alt-1) menu pushing the zero x end y button , it is impossible to get 0 in all the Offsets (Alt-5) menu. This probably meant to be so but running the g-code program from the cut circle wizard makes the circle totally wrong seize, are these problems connected?

[Tweakie.CNC]

OK, I think I understand now. 

Go into config / general config page and change IJ Mode to Inc

That should do it.

Tweakie.

[Trisdan]

YES, that's right,
Thank you very much! It made the circle perfect now !
That was far from obvious for me, to find that hidden adjustment in the ocean of settings.