Machine zero reference point machine zero machining origin tool change position program origin

Setting up a CNC lathe – FANUC G50

In (c)NC, G-Code, Setup, Start Here by Micah HoffmannLeave a Comment

Note: The G-code and procedures assume Fanuc controller, but concepts can be used across brands.

Making The Connection”

There are three important relationships you need to make when setting a CNC lathe.

  1. Machine Zero or Reference Point.
  2. Tool Change Position/Safe move (G50)
  3. Program Zero

1 and 2 are the XZ location of the center of the tool turret.

Machine zero reference point machine zero machining origin tool change position program origin

Setting Tool Length Offsets using Q-setter


(Note: If you need to know the manual version of this process, let me know)

For the love of sweet baby whoever, if you don’t already have a Q-setter automated tool offset system… go get your machine one now!
Haha, who am I to talk though, I dont even own my own machine.
But anyways use the q setter to automatically fill out the tool offset data for each tool.

Finding and setting your Machine Origin aka Tool Change Position aka G50 aka safe move

The G50 command is most widely known for its use with G96, but if you attach XZ values to the command it will act as your origin.

  1. Load your longest X tool, jog that tool to 1.00 away from ref surface.
  2. Load your longest Z tool, jog that tool to 1.00 from the face of your stock.
  3. G50 X(1) Z(2) where 1 is the absolute value from the controller during step 1, and 2 the absolute value from the controller during step 2.

Finding and setting G50 machining origin or tool change position

Putting it all together

G-CodeMeaning
N10 G20Inch Mode
N20 G50 X12.0 Z10.Set Machine Origin and Tool Change Position
N30 T0101Change to tool 1
N40 G96 S5000 M3Spindle on (CW) at 500 sfpm constant surface speed.
N50 X1.0 Z-.2 T101 M8Rapid move to point. Use tool edge control point when moving. Turn coolant on.

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