Use G94 Feed Per Minute
- When you program a 2D or 3D part
- When you machine a diameter that does not change on a rotary table
- When you use the 4th and 5th axes for positioning on 3+2 operations
- When you invoke G107
- G107 can also be used to set the default diameter of a cylindrical surface, independent of any cylindrical mapping that may be in effect.
- An A, B, or C address identifies which rotary axis holds the cylindrical surface
- G107 variables Q and
- Q defines the
diameter of the cylindrical surface. Sample code:
G107 B0. X-1. Q2.0
- R defines the
radius of the cylindrical surface. Sample code:
G107 C0. Y0. R2.
- When Q or R is used, a rotary axis must also be specified.
- If neither Q nor R is used, the last G107 diameter is used.
- If no G107 command has been issued since power-up, or if the last value specified was 0, the diameter is the value in Setting 34 and/or 79 for the rotary axis specified.
- When Q or R is specified, that value will become the new G107 value for the specified rotary axis.
- Q defines the diameter of the cylindrical surface. Sample code:
When to Use G93 Inverse Time
- When combined linear/rotary motion exists.
- Each combined linear/rotary move has a different distance. Thus the corresponding time values change for each code block, even if it does not change from the previously programmed feed value.
Invoking Inverse-Time Mode
A G93 is necessary to declare the feed mode on the initial move containing rotary motion.
General Rule: If a G93 is necessary to invoke inverse time mode, a G94 is necessary to cancel it.
This means that the first move of a sequence of normal XYZ linear moves with no rotary A/B/C words must have a G94 and an F that is interpreted in inches per minute.
Benefits of G93 Inverse Time
G93 lets the user follow a more complex tool path when linear/rotary axes are involved.
G93 lets the user have better control of the rotary's motion. This gives a more precise part with a better surface finish.
Settings and Parameters That Improve Inverse-Time Performance
Setting 85, Maximum Corner Rounding
Setting 191, Default Smoothness
Parameter 104, A Axis In Position Limit
Parameter 165, B Axis In Position Limit
Parameter 512, C Axis In Position Limit
Parameters 786, 787, 788, 789, 790, 791, 792, 793, 794, 795, 796, and 797, Command Fir Order
Parameters 884, 885, 886, 887, 888, 889, 890, 891, 892, 893, 894, 895, 896, 897, 898, and 899, Notch Center Frequency
Parameter 900, 901, 902, 903, 904, 905, 906, 907, 908, 909, 910, 911, 912, 913, 914, and 915, Notch Depth Factor