G72 End Face Stock Removal Cycle (Group 00)

First Block (Only use when using two block G72 notation)
* W - Depth of cut for each pass of stock removal, positive radius
* R - Retract height for each pass of stock removal
Second Block
* D - Depth of cut for each pass of stock removal, positive radius (Only use when using one block G72 notation)
* F - Feedrate in inches (mm) per minute ( G98) or per revolution ( G99) to use throughout G71 PQ block
* I - X-axis size and direction of G72 rough pass allowance, radius
* K - Z-axis size and direction of G72 rough pass allowance
P - Starting Block number of path to rough
Q - Ending Block number of path to rough
* S - Spindle speed to use throughout G72 PQ block
* T - Tool and offset to use throughout G72 PQ block
* U - X-axis size and direction of G72 finish allowance, diameter
* W - Z-axis size and direction of G72 finish allowance

*indicates optional

G18 Z-X plane must be active.

2 Block G72 Programming Example:

G72 Basic G Code Example: [P] Starting block, [1] Start position, [Q] Ending block.


G72 Tool Path: [P] Starting block, [1] Start position, [Q] Ending block.

This canned cycle removes material on a part given the finished part shape. It is similar to G71 but removes material along the face of a part. Define the shape of a part by programming the finished tool path and then use the G72 PQ block. Any F,S or T commands on the G72 line or in effect at the time of the G72 is used throughout the G72 roughing cycle. Usually a G70 call to the same PQ block definition is used to finish the shape.

Two types of machining paths are addressed with a G72 command.

• The first type of path (Type 1) is when the Z Axis of the programmed path does not change direction. The second type of path (Type 2) allows the Z Axis to change direction. For both the first type and the second type of programmed path the X Axis cannot change direction. If Setting 33 is set to FANUC, Type 1 is selected by having only an X-axis motion in the block specified by P in the G72 call.




• When both an X-axis and Z-axis motion are in the P block then Type 2 roughing is assumed.

G72 End Face Stock Removal Cycle: [P] Starting block, [1] X-Axis clearance plane, [2] G00 block in P, [3] Programmed path, [4] Roughing allowance, [5] Finishing allowance.

The G72 consists of a roughing phase and a finishing phase. The roughing and finishing phase are handled differently for Type 1 and Type 2. Generally the roughing phase consists of repeated passes along the X-axis at the specified feed rate. The finishing phase consists of a pass along the programmed tool path to remove excess material left by the roughing phase while leaving material for a G70 finishing cycle. The final motion in either type is a return to the starting position S.

In the previous figure the start position S is the position of the tool at the time of the G72 call. The X clearance plane is derived from the X-axis start position and the sum of U and optional I finish allowances.

Any one of the four quadrants of the X-Z plane can be cut by specifying address codes I, K, U, and W properly. The following figure indicates the proper signs for these address codes to obtain the desired performance in the associated quadrants.

G72 Address Relationships

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