In 1845 the British had invented the linear motor, the linear motor gap but it was too large inefficient, it can not be applied. 1870s Kollmorgen also launched, high efficiency and low cost but limits its development. Until after the 1970s, and gradually developed linear motor used in some specific areas, the 1990s began the linear motor used in machinery manufacturing, and now some of the world technologically advanced machining center manufacturers began to use in its high-speed machine tools, foreign well-known enterprises such as DMG, Ex-cell-O, Ingersoll, CINCI ATI, GROB, MATEC, MAZAK, FANUC, SODICK have launched the use of high-speed linear motor finishing center.

With the development of direct drive technology, linear motor contrast with the traditional "rotary servo motor and ball screw" driving method of causing the industry's attention.

HIWIN linear as the world leader in products, after the success in terms of ball screw and linear slide, in recent years, its own research and development and production of the linear motor, and achieved good results in the field of high speed and high precision.

Below the main reference HIWIN company's advanced high-speed mute screw SUPER S series (DN value of 220,000) and HIWIN linear motor made on several key characteristics of some of the more relevant industry to provide a reference.

Speed Comparison:

Speed linear motor has a considerable advantage, the linear motor speed 300m / min, acceleration of 10g; Ball screw speed was 120m / min, acceleration of 1.5g. From the comparison of the speed and acceleration, the linear motor has a considerable advantage, and will further improve the speed of the linear motor in the successful resolution of the heating problem, and "rotary servo motor and ball screw," the speed is limited by difficult further increase more.

From the dynamic response because the movement gap and institutional inertia and the complexity of issues such as the linear motor also has an absolute advantage.

Linear motor speed control because of its quick response and a wider speed range, can start instantly reach maximum speed, and can quickly stop running at high speed. Speed range up to 1: 10000.

Accuracy Comparison:

Precision linear motor actuator due to simple interpolation to reduce lag issues, positioning accuracy, reproducibility accuracy, absolute accuracy by the position detection feedback control will be more "rotary servo motor and ball screw" high, and easy to implement.

Linear motor positioning accuracy up to 0.1μm. "Rotary servo motor and ball screw" up to 2 ~ 5μm, and requires CNC- servo motors - seamless coupling - thrust bearings - Cooling system - precision rolling guide - Nut seat - bench the entire closed-loop system of transmission in part to reduce the weight, higher precision grating.

To achieve a higher stability, "rotary servo motor and ball screw" to take the biaxial drive linear motor is a high-heat-generating components, you need to take strong measures to cool, to achieve the same purpose, the linear motor will have to pay a higher price .

price comparison: 

Price price much higher linear motor, which is the reason for limiting the linear motor is more widely used.

Comparison of energy consumption:

In the linear motor energy to provide the same torque is "rotary servo motor and ball screw" more than doubled "rotary servo motor and ball screw" are energy-saving, energizing shaped actuator, linear motor control system reliability by stability, a great impact on the surrounding magnetic isolation and must take effective protective measures to cut off the strong magnetic field on rolling guide and the adsorption of magnetic iron dust.

The following examples make it easier for everyone to understand linear motors and "rotary servo motor and ball screw," some of the features:

Japanese company super high-speed gantry machining center. X, Y-axis linear motor drive V = 120m / min. Why the company does not use "rotation servo motor + ball screw (HIWIN SUPER S series)"? Because SUPER S Although DN value has gone from the traditional screw 70000-150000 then 220,000 speed the process, but because of the soft underbelly of a purely mechanical transmission, the line speed, acceleration, increased range of travel is always limited. If the selection of Φ40 × 20mm product, then vmax = 110m / min, due to the high nmax = 5500r / min speed travel range is limited by the critical speed Nc constraints obviously not too long. If using a large lead Φ40 × 40mm product, Vmax = 220m / min, which obviously can not meet the high precision positioning applications. DN value of 220,000 to reach a reflection of the HIWIN design and manufacturing standards. If we choose Φ40 × 20 (double head) mm products, n≈4000 ~ 5000r / min, V = at 80 ~ 100m / min using a state, its security, reliability, service life can be higher than expected. In fact so far, at high speed and high precision CNC metal cutting machine tools (CNC shaping machine except) speed V≥120m / min still use the successful example SUPER S-Series drive is not seen. "Rotary servo motor and ball screw," the best applications is actually: Requires V = 40 ~ 100m / min, acceleration of 0.8 ~ 1.5 (2.0) g, precision P3 level and above mid-range high-speed CNC equipment and some high-end CNC equipment .