Cutting Arc

[tipit]

Hi, I'm trying to cut an arc in aluminium and I can't get the tool positioning where I want it

My setting in the wizard:
X:3.3263
Y:9.25
Radius:8.6553
Start angle:0
Arc sweep:6
Outside

The G code outputed:

(Code by Newfangled Wizard, 23/09/09)
(Program Posted for Aluminum )
G0 G49 G40.1 G17
G80 G50 G90 G98 
G20 (Inch)
(***** Cut Arc *****)
M6 T1
M03 S15.3
M9
G00G43 H1 Z0.1
X12.1066 Y9.25
G01 Z-0.03 F3.75
G3 X12.0585 Y10.1678 I-8.7803 J0 F15
G00 Z0.1
X12.1066 Y9.25
G01 Z-0.06 F3.75
G3 X12.0585 Y10.1678 I-8.7803 J0 F15
G00 Z0.1
X12.1066 Y9.25
G01 Z-0.09 F3.75
G3 X12.0585 Y10.1678 I-8.7803 J0 F15
G00 Z0.1
X12.1066 Y9.25
G01 Z-0.12 F3.75
G3 X12.0585 Y10.1678 I-8.7803 J0 F15
G00 Z0.1
X12.1066 Y9.25
G01 Z-0.15 F3.75
G3 X12.0585 Y10.1678 I-8.7803 J0 F15
G00 Z0.1
X12.1066 Y9.25
G01 Z-0.18 F3.75
G3 X12.0585 Y10.1678 I-8.7803 J0 F15
G00 Z0.1
X12.1066 Y9.25
G01 Z-0.21 F3.75
G3 X12.0585 Y10.1678 I-8.7803 J0 F15
G00 Z0.1
X12.1066 Y9.25
G01 Z-0.24 F3.75
G3 X12.0585 Y10.1678 I-8.7803 J0 F15
G00 Z0.1
X12.1066 Y9.25
G01 Z-0.27 F3.75
G3 X12.0585 Y10.1678 I-8.7803 J0 F15
G00 Z0.1
X12.1066 Y9.25
G01 Z-0.3 F3.75
G3 X12.0585 Y10.1678 I-8.7803 J0 F15
G00 Z0.1
X12.1066 Y9.25
G01 Z-0.33 F3.75
G3 X12.0585 Y10.1678 I-8.7803 J0 F15
G00 Z0.1
X12.1066 Y9.25
G01 Z-0.36 F3.75
G3 X12.0585 Y10.1678 I-8.7803 J0 F15
G00 Z0.1
X12.1066 Y9.25
G01 Z-0.38 F3.75
G3 X12.0585 Y10.1678 I-8.7803 J0 F15
G00 Z0.1
M5 M9
M30

Can you tell me why the arc doesn't start at X:3.3263 and Y:9.25 on my work peace
Thank you

[RICH]

You didn't say what your tool diameter was.
Anyway, looks like the input values for X and Y define where the radius of the arc is from X and Y =0.
G90 is absolute mode, so the start of the arc is 3.3263+8.6553=11.9816+ 1/2 of the tool dia ( .25")=
12.1066 which would be the start point in absolute coordinates.

Now where should you place the tool relative to the start of the arc?
 If you were to reference all home and zero the x and y axis, the machine will rapid to
the start of the arc from X & Y =0.
Now if you were to put the values of 3.3263 for X and Y=9.25 in the DRO's, then you have defined
to Mach that you are at those coordinates, and the rapid to the distance will be be shorter to the start of the arc's

RICH

[tipit]

Thank you for the reply but this does not solve my problem or I don't understand your explanation.
Has it is I have a guide block on my table and I have set G54 to be the 0 coordinate for the X and Y axis from there I have drill holes and pockets exactly where I wanted them to be but for the arc it doesn't work out.
By the way the tool is .25" diam

[Ron Ginger]

The X and Y values entered into the wizard defines the center of the arc, not the starting point of the cut. t seems to me the wizard is doing the correct cut for a center and radius as you sepcified.

[tipit]

Thank you for your info, I will try this out