
PROGRAMMING
B–63444EN/01
1. GENERAL
23
The speed of the tool with respect to the workpiece when the workpiece
is cut is called the cutting speed.
As for the CNC, the cutting speed can be specified by the spindle speed
in rpm unit.
Tool
V: Cutting speed
φD
N rpm
Workpiece
v m/min
Fig.1.4 Cutting speed
<When a workpiece 200 mm in diameter should be machined at
a cutting speed of 300 m/min. >
The spindle speed is approximately 478 rpm, which is obtained from
N=1000v/πD. Hence the following command is required:
S478 ;
Commands related to the spindle speed are called the spindle speed
function (See II–9).
The cutting speed v (m/min) can also be specified directly by the speed
value. Even when the workpiece diameter is changed, the CNC changes
the spindle speed so that the cutting speed remains constant.
This function is called the constant surface speed control function
(See II–9.3).
1.4
CUTTING
SPEED–SPINDLE
SPEED FUNCTION
Examples