Feed Specification
Feed rate in turning centres can be specified using the F word address. However, it is possible to specify the feed rate in two forms in the normal mm/min format as well as mm/rev. The switching between the two formats is achieved by the use of G-codes :
- G98 feed in mm/min or inch/min
- G99 feed in mm/rev or inch/rev.
Normally, the default mode will be G98. It is also necessary to remember that the format for F word changes with G98 or G99 in force. In the case of G98 in metric mode it will be F50 while in inch format it is F032. The following examples should explain the usage of these codes.
N010 G98 F 200 (200 mm/min)
In the case of G99 in inch mode it will be F032 while in inch format it is F014.
N020 G21 G99 F1 (0.01 mm/rev)
N020 G21 G99 F1.0 (1.00 mm/rev)
N020 G21 G99 F100 (1.00 mm/rev)
Similar to the machining centres the F word can be placed anywhere in the program block, and remains modal. The specified Feed rate can be changed by the use of the Feed Rate Override switch on the control panel.