Mastering the NCT G81 Spot Drilling Cycle: Precision Boring Made Simple

NCT G81 drilling cycle is used for simple drilling/spot drilling operations.

Programming

G17 G81 X... Y... Z... R... F.. L...
G18 G81 Z... X... Y... R... F... L...
G19 G81 Y... Z... X... R... F... L..

Parameters

Following table X,Y,Z definitions will work for G17 Plane, for other planes these will change as for
G18 plane Z X will be hole position and Y will be drilling axis
G19 plane Y Z will be hole position and X will be drilling axis

Operations

The operations of the G81 cycle are

1. Rapid-traverse positioning in the selected plane
2. Rapid-traverse movement as far as point R
3. Drilling as far as the point Z, with feed F
4. Retraction
   • If  G99, retraction to point R, in rapid traverse
   • If G98, rapid-traverse retraction to the initial point

Programming Examples

Programming a Series of Bores

The programming of bores 10mm apart from each other with NCT G81 drilling cycle, here

%O7071(7.1)
N100 T1
N110 G54 G0 X0 Y50
N120 G43 Z50 H1
N130 S1000 M3 M8
N140 G81 XI10 Y50 R2 Z-10 L9
N150 G80
N160 G0 Z100
N170 M30
%

Programming Bore Series Example

The second series of bores is programmed as a new drilling cycle, where size is again to be specified in increment. Since both cycles would include the middle bore, the second series must be split into lower and upper part.

%O7072(7.2)
N100 T1
N110 G54 G0 X0 Y50
N120 G43 Z50 H1
N130 S1000 M3 M8
N140 G81 XI10 Y50 R2 Z-10 L9
N150 G80
N160 G0 X50 Y0
N170 G81 X50 YI10 R2 Z-10 L4
N180 G80
N190 G0 X50 Y50
N200 G81 X50 YI10 R2 Z-10 L4
N210 G80
N220 G0 Z100
N230 M30
%