How to Choose The Drive Motors

The main motors of CNC router machines on the market today can be roughly divided into two categories, namely servo motors and stepper motors. When you are choosing a motor, do you know how to choose the motors.Next please follow BuyCNC to know about the drive motors.

Japan Yaskawa servo motor

Japan Yaskawa Servo Motor

Drive Motors of desktop 5 axis cnc

Stepper Motor

What are stepper motor and servo motors

1.The Stepper motor is an open-loop control motor that converts electrical pulse signals into angular displacement or linear displacement. It is the main executive element in modern digital program control systems and is widely used. In the case of non-overload, the motor speed and stop position only depend on the frequency and pulse number of the pulse signal, and are not affected by the load change. When the stepper driver receives a pulse signal, it drives the stepper motor The set direction rotates at a fixed angle, called “step angle”, and its rotation runs step by step at a fixed angle. The angular displacement can be controlled by controlling the number of pulses, so as to achieve the purpose of accurate positioning; at the same time, the speed and acceleration of the motor can be controlled by controlling the pulse frequency, so as to achieve the purpose of speed regulation.

2.The servo motor can control the speed and position accuracy very accurately, and can convert the voltage signal into torque and speed to drive the control object. The rotor speed of the servo motor is controlled by the input signal and can respond quickly. It is used as an actuator in an automatic control system, and has the characteristics of small electromechanical time constant and high linearity. It can convert the received electrical signal into the motor shaft The angular displacement or angular velocity output. Divided into two major categories of DC and AC servo motors, its main feature is that there is no rotation when the signal voltage is zero, and the speed decreases at a uniform speed as the torque increases.

Features of stepper motors and servo motors

1. Stepper motor driver

The stepping drive motor system is currently the most used drive system on the market. The most popular is the three-phase hybrid stepper drive motor, which accounts for more than 90% of the market share. The reason is that the price is low and it is equipped with a high-division drive The post effect is good and can meet the basic needs of engraving machine processing. But the shortcomings are also obvious, For example: it will cause resonance, high working noise, torque will decrease after the speed is increased, and it can’t work for a long time.

2. AC Servo motor driver

The use of AC servo drive motor in engraving machines is still relatively small. The main reason is that the price is relatively high. In addition, the application of AC servo drive motors has certain requirements for the structure, electrical appliances, control system, and transmission system of the machine tool, just like the barrel principle. The shortest board determines the amount of water in the barrel, so AC servos motor are generally used in high-end models. AC servo motors has many advantages: fast response, large torque, high speed, high precision, low heat generation, continuous working for a long time, complete alarm system, etc. Disadvantages: Different equipment needs different servo parameters, and the adjustment parameters require high-level technical engineers.

The difference between stepper motor and servo motor

We have roughly understood the basic knowledge of Stepper drive motors and Servo drive motors, is there any difference between them, and how should we choose?

1. In Terms of Price:

The prices of the two motors are different. The servo motors are more expensive, especially the servo motors made in Germany and Japan, which are expensive and powerful. Our current servo motors are made in Japan. The price of The stepper motor is cheaper than servo motors of the same power. Our stepper motors are high quality stepper motors made in China.

2. Speed:

The Servo motors are excellent in applications requiring speeds greater than 4,000 RPM and for high torque at high speeds or requiring high dynamic response. The Stepper motor is good at the speeds less than 4,000 RPM and for low to medium acceleration rates and for high holding torque.

3. Work Efficiency:

Servo motors are very efficient, and its efficiency can almost reach 80%-90%. Compared with servo motors, stepper motors have lower efficiency, about 70%, and they will generate a lot of heat when they work.

4. Noise:

The servo motors hardly produce noise, while the stepper motor will produce some buzzing noise, but don't worry, BuyCNC provides you with high-quality drives that can reduce noise.

5.Different control accuracy:

The step angle of two-phase hybrid stepper motor is generally 3.6°, 1.8°, and the step angle of five-phase hybrid stepper motor is generally 0.72°, 0.36°. There are also some high-performance stepping motors with a smaller step angle. For example, a stepping motor used for slow-moving wire machine tools produced by Stone Company has a step angle of 0.09°; the three-phase hybrid stepper motor produced by Bergerlahr in Germany has a step angle of Code switch settings are 1.8°, 0.9°, 0.72°, 0.36°, 0.18°, 0.09°, 0.072°, 0.036°, which is compatible with the step angle of two-phase and five-phase hybrid stepping motors. The control accuracy of the AC servo motor is guaranteed by the rotary encoder at the back of the motor shaft. Take Panasonic's all-digital AC servo motor as an example. For a motor with a standard 2500-line encoder, the pulse equivalent is 360°/10000=0.036° due to the quadruple frequency technology used inside the drive. For a motor with a 17-bit encoder, every time the driver receives 217=131072 pulses, the motor makes one revolution, that is, its pulse equivalent is 360°/131072=9.89 seconds. It is 1/655 of the pulse equivalent of a stepping motor with a step angle of 1.8°.


Servo Motors CNC Router

cnc kit37

Stepper Motor CNC Router

How to choose different power machines

According to the power of the drive motor, CNC router machine can be divided into low-power drive motors and high-power drive motors. The low-power machine refers to the engraving machine with a small engraving motor power (generally 80-200W) . Due to its small engraving motor power, it can only be used for fine processing with less cutting surface each time. For example: badges, sand table models, surface processing of handicrafts, etc. This type of engraving machine can’t perform high -power engraving and cutting.

High-power engraving machine refers to an engraving machine with an engraving motor power above 700W. This type of engraving machine can not only perform low-power engraving, but also high-power engraving. For example: making crystal characters, all kinds of advertising signs, irregular cutting and forming of plates, processing of artificial stone, etc. Because of its high power, it can cut 30mm thick plexiglass or use a forming knife for high-power forming and engraving.

So in order to meet the needs of various industries, how should each industry choose the right power machine? 

The best motor power selection for various industries

1. Advertising engraving machine: The engraving object is a relatively soft material, so the spindle power of the advertising engraving machine can be within 1.5kw-3.0kw. This choice can achieve the purpose of engraving and save costs.

2. Woodworking engraving machine: The spindle motor of the woodworking engraving machine can be selected according to the hardness of the wood to be processed. Its power is generally around 2.2kw-4.5kw, and this combination is also the most reasonable.

3. Stone engraving machine: The spindle power of the stone engraving machine used by manufacturers is relatively higher, generally about 4.5kw-7.5kw, and the most commonly used is 5.5kw spindle motor

4. Tombstone engraving machine: The spindle power of the tombstone engraving machine should also be selected according to the hardness of the processed stone. The general power of 3.0kw-4.5kw can meet customer needs

5. Jade carving machine: The power of the main shaft motor of the jade carving machine is generally 2.2kw-3.0kw due to its small bed.

Too much power of the spindle motor not only wastes electrical energy, but also increases the purchase cost. If the power is too small, the engraving power demand will not be available, so it is very important to choose a suitable spindle motor power!

Finally, to make a summary, if your budget is high enough and you need a CNC router machine for high-precision machining, then please choose servo motors. If you want to use CNC router machine for simple processing, then the stepper motors is a good choice.

BuyCNC has a variety of servo motors and stepper motor CNC router machine for you to choose from. If you don’t know how to choose the servo motors and stepper motors , you can contact us and we will provide you with the best solution.

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