The hottest time servo application case five axis

Time servo application case - five axis linkage floor milling and boring machine

I. Introduction

with the development of micro processing technology, high-performance power semiconductor power devices and other product manufacturing processes and the increasing improvement of cost performance, AC servo technology is more and more used in electromechanical equipment. We have set up microcomputer real-time control devices in startec. Due to the solid structure of three-phase AC asynchronous induction motor (squirrel cage motor) It is easy to manufacture, reliable in operation, convenient in maintenance and low in price. It has a good development prospect and is one of the development directions of servo technology in the future

large and heavy floor type CNC milling and boring machines are machine, electric and hydraulic integrated technology intensive products, and their performance requirements can realize multi axis control and five coordinate linkage; It can process large workpieces with complex curved surfaces; It is a key equipment with high precision, high performance and high efficiency in the machining industry. At present, this type of products basically rely on imports from abroad. If the localization is realized on the premise of ensuring the performance, especially the use of the localized all digital servo system, the cost can be greatly saved, the foreign technological monopoly and constraints can be broken, and the development of national industry can be promoted

floor type CNC milling and boring machine with time technology AC servo control system

II. Technical requirements

1 As a heavy precision machining equipment, floor CNC milling and boring machine requires high speed regulation performance. The speed regulation ratio is required to be greater than 1:3000

2. In the process of speed regulation with load, it is necessary to ensure the stable output of sufficient torque, which can realize the smooth operation of the feed shaft at low speed and the regulatory filing and large torque output of the market

3. In the process of heavy-duty machining, the stability of running speed is guaranteed under the condition of large-scale fluctuation of load (torque)

4. Solve the problems existing in the existing DC servo system

the AC servo controller of time technology has the following characteristics:

1 Full digitalization:

the AC servo controller of optical technology is full digitalization technology, its speed control range is 0Hz ~ 500Hz, and its control accuracy is 0.01Hz at 250Hz and 0.02hz at 500Hz. The controller can meet the needs of large-scale stable, accurate and high-precision speed control of CNC milling and boring machine

2. High reliable speed regulation and overload performance:

compared with the frequency converter, its speed curve is linear (the speed curve is shown in Figure 1), which enables the machine tool to operate continuously and normally under different types of machine conditions without speed fluctuation under the working conditions of frequent start, stop, forward rotation, reverse rotation and braking control during the processing process. Moreover, the system has excellent overload characteristics. It can achieve 300% of the rated torque output at the rated speed of the nameplate, which is completely different from the working curve of the general frequency converter (see Figure 2), ensuring that the machine tool can still run smoothly in the process of heavy-duty processing when the load is large and it is difficult for other companies to open the market fluctuation

3. Independent control of speed and torque:

the optical servo controller can realize the "decoupling control" of any speed and torque of three-phase asynchronous motor. Thus, the speed is constant when the load torque changes. Similarly, the optical servo controller can change the output torque in real time to meet the requirements of machining large workpieces with complex surfaces under the condition of stable speed operation (high torque output at low speed of 0.3 R/min and no fluctuation crawling)

4. Type selection of three-phase AC asynchronous motor

at present, the domestic production technology of three-phase AC asynchronous motor is very mature, with high reliability, and the capacity can reach more than hundreds of kW; The low-speed rotation is stable and the torque is large (no magnetic weakening problem); And it can be applied to motors with large number of poles, which improves the low-speed speed regulation performance and greatly expands the application field of servo motors

users can select specially designed servo motors according to their needs; You can also use an ordinary universal three-phase asynchronous motor. You only need to install an encoder on the rear shaft of the motor without making other hardware changes. Therefore, it is very convenient to carry out the transformation of old models and the design of new models

III. application

taking the vertical floor boring and milling machine as an example, the original machine tool adopts the DC speed regulation system. On the basis of maintaining the original mechanical structure, the three-phase asynchronous servo motor is used to replace the DC motor, and the time servo control system is used to replace the original DC speed regulation system

the field pictures of each feed shaft are as follows:

horizontal feed of column

vertical feed of headstock

boring shaft (inner) and RAM (outer)

main indicators achieved by the system:

motor related parameters

speed regulation range: 0.01~250hz (gear shift stepless speed change)

rated speed: 4 pole 1500rpm

conclusion

Application of AC servo controller of time technology in the control system of large and Heavy CNC milling and boring machines,the, It gives full play to the characteristics of low-speed, high torque and stable speed control of the system, so that large and heavy equipment can start smoothly at zero speed, and the ultra-low speed feed performance is significantly improved, so the application prospect is very broad