Technical data

SERVICES FOR INCREASED ACCURACY OF

MACHINE TOOLS

Stick slip

The phenomenon of stick slip can occur on wide flat box

ways where the stick slip compensation can be used effec-

tively. The slide movement can be initiated by a “kick start”

through a parameter with preset time and speed impulse

value, and by immediately returning the speed to the normal

value as soon as the slide started to move. This eliminates

excess speed caused by increasing speed command gener-

ated by position control loop for stick slip. The position control

loop oscillated by excess speed significantly decreases the

dynamics of the servo circuit.

Straightness

The straightness of moving slides is essential for machine tools

as well as for the positioning accuracy. However, builders

tend to develop the best geometry and straightness for their

machine tools, improving machining or fitting accuracy above

a certain value is not practical. Electronic compensation can

be used efficiently in these cases. The straightness deviation

of axes has to be measured before adjusting the relevant pa-

rameter. The control manages to move axes perpendicular to

movement by setting the value after filling in measurement re-

sults.

Thermal

deformation

compensation

TDC

Compensation of thermal deformation based on tempera-

ture measurement

Direct position measurement by linear scale is a perfect solu-

tion that compensates thermal deformation of linear axes of

a machine tool. Although deformation of elements that can

not be or difficultly measured directly is a significant problem,

for example at the headstock of C column type milling ma-

chines. The headstock is heated by spindle bearings, spindle

motor, and cooled by coolant and the active cooling of spin-

dle motor and spindle. Thermal deformation of headstock can

be compensated by self-adjusting software model integrated

in NCT control, based on signals of thermal measurement

sensors in headstock.

NCT asynchronous drives and motors exhibited at the EMO

NCT synchronous servomotors and built-in spindle motor

exhibited at the EMO

NCT booth at the EMO exhibition in Hannover Germany

NCT 201 controls at the EMO exhibition