
3.SELECTING A MOTOR SPECIFICATIONS FOR THE αiS/αi SERIES B-65262EN/03
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Servo Motor Selection Data Table
Gravitational system of units
User name Kind of machine tool
CNC equipment Type of machine tool
Spindle motor
Item Axis
Specifications of moving object
* Weight of moving object (including workpiece, etc.) kgf
* Axis movement direction (horizontal, vertical, rotation, slant)
* Angle of the slant deg
* Counterbalance (forth) kgf
* Table support (sliding, rolling, static pressure)
Diameter mm
Pitch mm* Ball screw
Length mm
Diameter of pinion mm
* Rack and pinion
Thickness of pinion mm
* Friction coefficient
Machine tool efficiency
* Total gear ratio
Mechanical specifications
Traveling distance of the machine tool per revolution of the motor mm/rev
Least input increment of NC mm
* Rapid traverse feedrate mm/min
Motor speed in rapid traverse 1/min
* Total load inertia applied to the motor shaft (*1)
kgf⋅cm⋅s
2
Inertia of coupling, reduction gear and pulley
kgf⋅cm⋅s
2
* Steady-state load torque (*2)
kgf⋅cm
* Cutting thrust kgf
Maximum cutting torque
kgf⋅cm
Required percentage duty cycle/ON time with the maximum cutting
torque
%
Positioning distance mm
Required positioning time (*3) sec
In-position set value mm
Rapid traverse positioning frequency (continuous, intermittent) times/min
Dynamic brake stop distance mm
Motor specifications and characteristics
Motor type
Pulsecoder
Shaft shape
Brake (Yes/No)
Feed-forward during rapid traverse (Yes/No)
T
1
m⋅sec
Acceleration/deceleration time constant in rapid traverse
T
2
m⋅sec
Position loop gain 1/sec
Be sure to fill in units other than the above if used. (Sometimes "deg" is used instead of "mm" for the rotary axis.)
* Note required values for selecting the motor.
*1 If possible enter the total load inertia. If you enter the inertia of coupling, reduction gear and pulley (motor shaft conversion) in the next item, you can also
calculate the total load inertia by adding the weight of the moving object and ball screw values by logical calculation in the case of a linear shaft.
*2 Steady-state load torque refers to the steady-state components such as friction (holding torque is included in the case of a gravity shaft) when the motor
is rotating at a fixed speed. Enter the state-state load torque as far as possible. If details are unknown, use a value calculated logically from the weight
and friction coefficient. Enter the steady-state load torque of the rotary axis in the same way as for load inertia as it cannot be calculated logically. You
need not enter the torque required for acceleration/deceleration.
*3 Servo delay and setting times must also be taken into consideration in the positioning time.
(**) Comments