# Fanuc Lathe: Locating Program Zero 275

This class describes how to determine work offsets and tool geometry offsets on the Fanuc 0-C lathe control during setup.

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## Class Details

Class Name:
Fanuc Lathe: Locating Program Zero 275
Difficulty:
Intermediate
Number of Lessons:
14
Spanish

## Class Outline

• Objectives
• What Is Program Zero?
• The Work Coordinate System
• Considerations for Selecting Program Zero
• Tool Geometry Offset Methods
• Determining Tool Geometry Offsets: Off the Machine
• Determining Tool Geometry Offsets: X-Axis on the Machine
• Determining Tool Geometry Offsets: Z-Axis on the Machine
• Determining Tool Geometry Offsets: Tool Pre-Setter
• Entering Tool Geometry Offsets: Tool Pre-Setter
• Determining Work Offsets
• Entering Work Offsets Using MZ0
• Entering Radius and Tip Offsets
• Summary

## Objectives

• Compare program zero to machine zero.
• Describe the work coordinate system.
• Identify common locations for program zero on the lathe.
• Identify common methods for setting tool geometry offsets.
• Describe how to determine tool geometry offsets for tools off the lathe.
• Describe how to determine tool geometry offsets on the lathe manually for the X-axis.
• Describe how to determine tool geometry offsets manually on the lathe for the Z-axis.
• Describe how to determine tool geometry offsets with the tool pre-setter.
• Explain how to use the Fanuc 0-C control to enter geometry offsets with the tool pre-setter.
• Describe how to determine a work offset on the lathe.
• Describe entering work offsets using MZ0.
• Describe entering radius and tip offsets.

## Glossary

Vocabulary Term Definition
[GEOM] A soft key option that activates the tool geometry offset screen.
[W.SHFT] A soft key option that activates the work offset screen.
centerline An imaginary straight line that runs through the center of a cylindrical part. On the lathe, the centerline is parallel to the Z-axis.
CURSOR arrow keys The up and down arrow keys located on the MDI keypad that allow an operator to move through various screens and fields in the control, edit and search for CNC programs, and move the cursor through the program or screen options.
G30 A command that sets the X-axis and Z-axis coordinates at a secondary home position.
G41 A command that sets the tool nose radius offset for tools moving on the left side of the programmed path.
G42 A command that sets the tool nose radius offset for tools moving on the right side of the programmed path.
G50 A command that defines the work coordinate system when used in a program block.
geometry offset Any offset that adjusts machine components to compensate for the unique shape of a particular cutting tool. On the lathe, the geometry offsets are tool length and tool nose radius and tip compensation.
incremental mode A program mode, usually specified with a U code, that allows an operator to add value to offsets and set an incremental position along the X-axis.
input buffer A temporary location on a computer that holds all incoming information before it continues to the control for processing.
INPUT key A key located on the MDI keypad that allows an operator to enter data into the input buffer. This key is also used to input data from an input/output unit.
job sheet A document that includes all manufacturing specifications for a lot of parts.
machine coordinate system An unchangeable coordinate system that has machine zero as its origin.
machine zero The position located at the farthest possible distance in a positive direction along the machine axes. This position is permanently set for each particular CNC machine.
manual reference position return Using the handle or other manual controls to return the turret to machine zero or home position.
OFSET key A function key on the MDI keypad that allows an operator to view and adjust tool geometry, wear, or workshift offsets.
part program A series of instructions used by a CNC machine to perform the necessary sequence of operations to machine a specific workpiece.
program zero The position that acts as the origin for the part program of a particular workpiece. This position is unique to each workpiece design, and it is selected by the part programmer.
qualified tooling Tooling used with the lathe that consists of separate clamping units and cutting heads that are interchangeable. The position of each cutting edge is held to very tight tolerances.
radius offset An offset used on the lathe that slightly adjusts the tool to compensate for the rounded tip of an insert during contouring, chamfering, and other multi-axis operations.
stylus The precision tip on the tool pre-setter that electronically records the turret position once a tool tip contacts its surface.
tip offset An offset used on the lathe that indicates one of nine possible orientations for a particular tool. Tip offsets are used in conjunction with radius offsets.
tool nose radius The rounded tip on the cutting edge of a single-point tool. The greater the nose radius, the greater the degree of roundness at the tip.
tool pre-setter A device on the lathe used to quickly determine tool geometry offsets on the X-axis and Z-axis. The tool tip contacts surfaces on the sensor, which instantly records the turret position in the offset screen.
work coordinate system A variable coordinate system that has program zero as its origin.
work offset An offset used to adjust the location of every tool loaded in the machine. On the lathe, the work offset changes the position of the turret in both the X- and Z-axes.