The linear motor is characterized by direct linear motion, and its advantages are as follows compared with "rotating motor, rolling screw" which indirectly produces linear motion

(1) Without mechanical contact, the transmission power is generated in the air gap. The linear module has no friction except the linear motor guide rail:

(2) Simple structure and small volume, we can realize our linear drive by using less parts and parts, and this is only one moving part:

(3) The travel of operation is theoretically unrestricted and its performance will not be affected by the change of stroke size:

(4) Its operation can provide a wide range of speed operation, which covers from a few microns per second to several meters, especially in high-speed state is a prominent advantage:

(5) The acceleration is very large, up to 10g:

(6) The motion is stable because there is no other mechanical connection or conversion device for servo electric cylinder except for the linear guide rail or air bearing which supports the function:

(7) The accuracy and repetition accuracy are high, because the intermediate link which affects the accuracy is eliminated, the accuracy of the system depends on the position detection element, and the appropriate feedback device can reach submicron level

(8) Maintenance is simple, because of the small parts, no mechanical contact during movement, which greatly reduces the wear of parts, only a little or no maintenance is needed, and the service life is longer. Performance comparison table of linear motor and "rotating motor, ball screw" performance rotary motor + ball screw linear motor. Disadvantages: from the surface, linear motor linear motor can gradually replace ball screw to become the mainstream of driving linear motion. But the fact is that after linear motor drive is widely used, some problems that have not been paid attention to in the past begin to emerge: first, the power consumption of linear motor is large, especially when the machine tool is moving with high load and high acceleration speed, the instantaneous current of machine tool brings heavy load to the power supply system of workshop; The second is high vibration, the dynamic rigidity of linear motor is low, which can not play the role of buffer damping, and it is easy to cause resonance of other parts of machine tool when it is moving at high speed; Third, the linear motor actuator fixed on the bottom of the workbench is a high heating part, and the installation position is not conducive to natural heat dissipation, which poses a great challenge to the constant temperature control of the machine tool; Fourth, it is impossible to lock itself. In order to ensure the safety of operation, the linear motor driven moving axis, especially the vertical axis, must be equipped with additional locking mechanism, which increases the complexity of the machine tool. In the application of linear motor, in addition to the above defects, the single axis arm also sees its advantages one-sided. The main advantages of linear motor are high speed and high acceleration. However, in the machining process of machine tool, the auxiliary time saved when acceleration exceeds 10m/s2 is not significant for the whole processing process. Only in the process of very short working hours, high acceleration speed is intentional, that is to say, for the cutting of single complex parts such as die and air blade, The advantages of linear motor are not obvious. For the above reasons, the machine tool enterprises that choose to develop linear motor adopt the method of "advantages and disadvantages". First, linear motor is applied to the occasions of mass production, positioning movement and frequent direction change, such as auto parts processing machine, rapid prototyping machine and semiconductor production machine, etc; The second is used in low load and large range of process, such as electric machine tool, water cutting machine, plasma cutting machine, etc.