Tormach PCNC 440 - 7.4.3 Simple Drilling Cycle - G81

Chapter 7
132
UM10372_PCNC440_Manual_0221A
PROgRAMMiNg
7.4.3 Simple Drilling Cycle – G81
The G81 cycle is intended for drilling. Program: G81 X~ Y~ Z~ A~ R~ L~
Step # Description
1 Preliminary canned cycle moon
2 Move the Z-axis only at the current feed rate to the Z posion
3 Retract the Z-axis at traverse rate to clear Z
The following examples demonstrate how the G81 canned cycle works in detail. Other canned cycles
work in a similar manner.
Example 1: Suppose the current posion is (1, 2, 3) and the XY-plane has been selected and the
following line of NC-code is interpreted.
G90 G81 G98 X4 Y5 Z1.5 R2.8
This calls for absolute distance mode (G90), old “Z” retract mode (G98) and calls for the G81 drilling
cycle to be performed once. The X number and X posion are 4. The Y number and Y posion are 5.
The Z number and Z posion are 1.5. The R number and clear Z are 2.8. The following moves take place :
Step # Description
1 G00 moon parallel to the XY-plane to (4,5,3)
2 G00 moon parallel to the Z-axis to (4,5,2.8)
3 G01 moon parallel to the Z-axis to (4,5,1.5)
4 G00 moon parallel to the Z-axis to (4,5,3)
Example 2: Suppose the current posion is (1, 2, 3) and the XY-plane has been selected and the
following line of NC-code is interpreted.
G91 G81 G98 X4 Y5 Z-0.6 R1.8 L3
This calls for incremental distance mode (G91), old “Z” retract mode and calls for the G81 drilling
cycle to be repeated three mes. The X number is 4, the Y number is 5, the Z number is -0.6 and the
R number is 1.8. The inial X posion is 5 (=1+4), the inial Y posion is 7 (=2+5), the clear Z posion
is 4.8 (=1.8+3) and the Z posion is 4.2 (=4.8-0.6). Old Z is 3.0.
The rst move is a traverse along the Z-axis to (1,2,4.8), since old Z < clear Z.
The rst repeat consists of three moves.
Step # Description
1 G00 moon parallel to the XY-plane to (5,7,4.8)
2 G01 moon parallel to the Z-axis to (5,7, 4.2)
3 G00 moon parallel to the Z-axis to (5,7,4.8)
The second repeat consists of three moves. The X posion is reset to 9 (=5+4) and the Y posion to
12 (=7+5).