The G82 canned cycle is commonly used in CNC milling operations for precise drilling with a dwell at the bottom of the hole. This cycle allows for a pause, or dwell, which can be useful for chip breaking or to ensure a clean hole bottom in blind holes.
Usage Format
The basic format for a G82 canned cycle is as follows:
G82 R... Z... P... F... (other optional parameters)
- R: Position of the plane to which the tool retracts after drilling.
- Z: Position for the depth of the hole.
- P: Dwell time at the bottom of the hole.
- F: Feed rate for the drilling operation.
Explanation
When the G82 cycle is activated, the tool moves rapidly to the R plane, then proceeds at the specified feed rate (F) to the Z depth. Once the tool reaches the Z depth, it dwells for the duration specified by P (in milliseconds or seconds, depending on the machine’s setup). After the dwell, the tool retracts back to the R plane.
Example
Consider a scenario where we need to drill a hole with a depth of -10mm, a dwell time of 1 second, and a feed rate of 100mm/min. The tool should retract to a safe height of 5mm above the workpiece.
Text Diagram:
(Starting Point)
|
| R5
| ↓ Rapid movement
|
| ↓ F100 Feed rate
| Z-10
| * Dwell P1000
| Z-10
|
| ↑ Rapid movement
| R5
(End Point)
Program Example:
% (Example CNC program for G82 Drilling Canned Cycle with Dwell)
O1000 (Program number)
T1 M06 (Tool change to tool 1)
G90 G17 G20 (Absolute positioning, XY plane, inch mode)
G00 X1 Y1 (Rapid move to starting position)
S500 M03 (Spindle speed 500 RPM, spindle on clockwise)
G43 H01 Z1 M08 (Tool length compensation, coolant on)
G82 R0.2 Z-0.394 P1000 F3.937 (G82 cycle with dwell)
X2 Y2 (Move to next hole position)
X3 Y3 (Move to next hole position)
G80 (Cancel canned cycle)
G00 Z1 M09 (Move to safe height, coolant off)
G28 G91 Z0 (Return to home position)
M30 (End of program)
%
In this example, G82 R0.2 Z-0.394 P1000 F3.937 represents the G82 cycle with a retract plane of 0.2 inches, a drilling depth of -0.394 inches, a dwell time of 1000 milliseconds (1 second), and a feed rate of 3.937 inches per minute.