Along with the
development of the direct drive technology, linear motor and the
traditional 'rotating servo motor ball screw driven by way of contrast
to the attention of the industry. Now some of the world advanced
technology center processing factory started on its high-speed machine
tool applications.
Because
of the precision linear motor drive mechanism simple and reduce the
interpolation lag problem, positioning accuracy and repeat precision,
the absolute accuracy, by detecting position feedback control will be
the 'rotating servo motor ball screw' is high, and easy to implement.
Linear motor position precision can reach 0.1 microns. 'Rotary servo
motor ball screw' to a maximum of 2 ~ 5 microns, and require CNC servo
motor - no gap connecting shaft device - thrust bearing - cooling system
- the high precision rolling guide - nut - workbench closed-loop
transmission part of the whole system to lightweight, grating precision
is higher. To achieve high stability, 'rotating servo motor ball screw'
take biaxial drive, linear motor is high fever parts, take strong
measures to cold to achieve the same purpose, linear motor were far more
costly.
Speed
linear motor has a considerable advantage, linear motor speed of 300
m/min, the acceleration achieve 10 g; Ball screw speed of 120 m/min, the
acceleration of 1.5 g. From the contrast of speed and acceleration,
linear motor has a considerable advantage, and linear motor speed after
successfully solve the problem of heat will also further improve, and
the 'rotating servo motor ball screw' in speed is restricted to improve
more.
Life in terms
of linear motor for gap is installed between the moving parts and fixed
parts, no contact, not because of the dynamic high-speed reciprocating
motion of wear and tear, long use between changes in movement and
positioning accuracy, suitable for the occasion of high precision. Ball
screw cannot ensure accuracy in the high speed reciprocating motion,
because of the high speed friction, the wear and tear of lead screw nut,
affecting the precision of the motion requirements. Can't meet the
demand for high precision occasions.