In CNC machining, precision and efficiency are paramount. The Haas G72 Type I Rough and G70 Finish Facing Cycle are integral parts of the CNC lathe programming that help achieve these goals. These cycles automate the roughing and finishing processes, reducing manual coding and potential errors.
Usage Format
The G72 cycle is used for rough facing, removing large amounts of material in preparation for finishing. The G70 cycle is then used to finish the face to the desired specifications.
Explanation
G72 Type I Rough Facing Cycle:
- G72 initiates the rough facing cycle.
- W sets the depth of cut for each pass.
- R is the retract height after each pass.
- P and Q define the start and end block numbers of the path to rough.
- F sets the feed rate.
G70 Finish Facing Cycle:
- G70 initiates the finish facing cycle.
- P and Q again define the start and end block numbers, but this time for the finishing path.
Example
Here’s a text diagram and a program example to illustrate the G72 and G70 cycles:
% O0001 (G72 and G70 Example)
(T1 M06) (Tool change to tool 1)
G50 S1200 (Set max spindle speed)
G97 S500 M03 (Set spindle speed and start spindle CW)
G00 X1.0 Z0.1 (Rapid move to start position)
G72 P1 Q2 W0.05 R0.01 (Rough facing cycle)
N1 G00 X0 Z0 (P1 - Start of rough facing path)
G01 Z-0.5 F0.2 (Move to depth of -0.5 at feed rate of 0.2)
N2 G00 X1.0 (Q2 - End of rough facing path)
G70 P1 Q2 (Finish facing cycle)
M30 (End of program)
%
Text Diagram:
|<-- Facing (G72) -->|<-- Finish (G70) -->|
| | |
| | |
| | |
| | |
| | |
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|____________________|____________________|
0 0.5 1.0
In this example, the G72 cycle rough faces the workpiece from the center (X0) to a radius of 0.5 inches, with a depth of cut set by W0.05 and a retract height of R0.01. After roughing, the G70 cycle finishes the face to the same radius.