machining trouble

[an0n]

Hello, everyone, I am trying to machine a pocket which is a round hole in the middle in my part, the trouble is that the size comes out 2mm smaller then drawn, unless I draw the hole oversized in my cad program.
Does anyone have any idea why this is happening, or have been through anything similiar?

/Anders

[Al_The_Man]

Tool offset correct?
Maybe if you post the program with the tool dia you are using it might help.
Al.

[an0n]

the tool offset should be correct, it's just a matter of setting up the correct tool size in the create/select tool dialog isnt it?

[Karl_T]

Any time I got a problem like this I start beaking it into smaller pieces.

I'd put a felt tip pen in the spindle and a piece of paper for my part. Then run a manually G code program to draw a circle: (NOTE: your version control probably doesn't Gcode exactly like my control)

G00 X0 Y0
Z -1.0
G01 X1 F10
G02 X1 Y0 I0 J0
G00 Z0
X0 Y0

Then I'd set up T1 for a 1/2 inch cutter and insert the command T1 G41 after the Z -1 line. See if it offsets as you expect. If so, the problem is in the cam package.

Karl

[an0n]

I'll try it after 16:00 today, Thanks for the help