Mitsubishi Electric MELDAS C6 Programming Manual page 65

7. Feed Functions
(Example) When the feedrate is designated as "f" and the linear axes (X and Y) are to be
controlled using the circular interpolation function.
In this case, the feed rate of the X and Z axes will change along with the tool
movement. However, the combined speed will always be maintained at the constant
value "f".
When controlling rotary axes
When rotary axes are to be controlled, the designated feedrate functions as the rotary speed of the
rotary axes or, in other words, as an angular speed.
Consequently, the cutting feed in the tool advance direction, or in other words the linear speed,
varies according to the distance between the center of rotation and the tool. This distance must be
borne in mind when designating the feedrate in the program.
(Example) When the feedrate is designated as "f" and rotary axis (CA) is to be controlled ("f"
units = °/min)
Rotation
center
In this case, in order to make the cutting feed (linear feed) in the tool advance
direction "fc" :
Therefore, the feedrate to be designated in the program must be :
When linear and rotary axes are to be controlled at the same time
The controller proceeds in exactly the same way whether linear or rotary axes are to be controlled.
When a rotary axis is to be controlled, the numerical value assigned by the coordinate word (A, B,
C) is the angle and the numerical values assigned by the feedrate (F) are all handled as linear
speeds. In other words, 1° of the rotary axis is treated as being equivalent to 1mm of the linear axis.
Consequently, when both linear and rotary axes are to be controlled simultaneously, the
components for each axis of the numerical values assigned by F will be the same as previously
described "When controlling linear axes". However, although in this case both the size and
direction of the speed components based on linear axis control do not vary, the direction of the
speed components based on rotary axis control will change along with the tool movement (their
size will not change). This means, as a result, that the combined tool advance direction feedrate
will vary along with the tool movement.
7.5 Feedrate designation and effects on control axes
P (tool end point)
2
c
r
fc = f × π • r
180
180
f = fc ×
π • r
57
Angular speed is "f"
Linear speed is :
P (tool start point)
1
π •r•f
180