Technical data

SERVICES FOR INCREASED ACCURACY OF

MACHINE TOOLS

Reversal error

This is the basic compensation for each machine tool control.

Most of the time the movment of a slide is generated by the

rotation of a servomotor. When reversing direction, the motor

rotates for a short interval as the slide does not move yet, be-

cause of the backlash and flexibility of mechanical parts that

transform rotational motion into straight-line or rotational mo-

tion. This movement lag can be corrected by the value in the

“Backlash” parameter that compensates also linear and ro-

tating axes.

Linear accuracy

The most commonly used and most appropriate measuring

device is the laser interferometer that measures the effective

position of axes between movements by 0,1 micron resolu-

tion. The measuring results can be saved in the Pitch Error

Compensation parameters of the CNC control and the meas-

ured position can be modified in each point based on these

data. The reversal error compensation will be performed au-

tomatically if the laser measurement is done in both directions

of an axis.

Reversal

acceleration

This compensation reduces significantly the oscillation of

servo axis and the dynamics of a machine tool equipped with

linear scale can be increased, even in case of very “loose”

mechanics. While machining with low feed or in circular in-

terpolation the speed of the servomotor will be the highest

when the slide starts to move due to backlash. Usually there

will be a state of oscillation that is difficult to manage. The

reversal acceleration will speed up the servo motor and after

a preset time or distance the normal speed signal will be re-

stored. This needs to be set the way, that when the slide starts

to move the servo drive has already been programmed for

the normal feed command.

NCT 201 on a Tong Tai Topper TNL-130AL machine JINN FA-NCT gang-type lathe with supporter and barfeeder

VD-510S new tapping centre with NCT 201 New BUFFALO LT-52 slant-bed lathe with NCT 201