The industrialized countries of the world have made great strides in the structure of the national economy by developing numerical control technology and establishing a numerical control machine tool industry, which has driven the manufacturing industry into a new stage of development. CNC machine tools are an important part of the third industrial revolution in the world. It is not only an important basic equipment for the electromechanical industry, but also the main means for the modernization of industries such as automobiles, petrochemicals, electronics and modern medical equipment. Although the output value of the numerically-controlled machine tool industry is far inferior to that of the automobile and chemical industries, efficient CNC machine tools have brought modern production methods and high efficiency growth to the manufacturing industry. This is a huge source of power for the development of the national economy. In particular, the effects of radiation and ripple effects generated by the expansion and extension of CNC technology in the manufacturing industry are sufficient to bring profound changes to the industrial structure, product structure, manufacturing methods, and management models of the machinery manufacturing industry.
The computer numerical control (CNC) system is mainly composed of several parts in the dashed box shown in Fig. 1. The double-dot drawing frame is the control object of the numerical control system. Here, the numerical control machine tool is taken as an example for illustration.
Figure 1 The composition of the numerical control system
1. Operator panel The operator panel is the tool for the operator to interact with the CNC machine (system). On the one hand, the operator can operate, program, debug or set and modify the machine tool parameters through the operation panel. On the other hand, the operator can also know or query the CNC machine (system) through the operation panel. Operating status.
The operation panel is mainly composed of a button station, a status lamp, a key array (functions like a computer keyboard), and a display, as shown in FIG. 2 .
Figure 2 Operation panel
2. Input/output device The input output device is a device that the CNC system interacts with external devices. The interactive information is usually a part program. The part machining program to be recorded on the control medium is input to the CNC system or the debugged part machining program is stored or recorded on the corresponding control medium via the output device. The control media and input/output devices commonly used for CNC machine tools are shown in the following table.
Table control media and input and output devices
In addition, modern numerical control systems can generally use communication methods to exchange information between CNC systems and external devices. This type of information exchange is the basic technology for implementing DNC, FMS, and CIMS. At present, the commonly used communication methods on CNC machine tools are:
- Serial communication (RS232 and other serial ports).
——Automatically control dedicated interfaces and specifications (DNC mode, dedicated interface cards, etc.).
- Network technology (Internet, LAN, etc.)
3. Computer Numerical Control (CNC) Device (or CNC Unit) A computer numerical control (CNC) device is the core of a computer numerical control system. Its main function is to perform corresponding processing (such as motion track interpolation calculation, machine tool input and output processing, etc.) according to the input part machining program, and then output the control command to the corresponding execution part (servo unit, drive device, PLC, etc.), processing Need out the parts. All these tasks are coordinated and coordinated by hardware and software within the CNC device, so that the entire system can work in an orderly manner. The CNC device is mainly composed of a computer system, a position control board, a PLC interface board, a communication interface board, an extension function module, and a corresponding control software module.
4. Servo Units, Drives, and Measuring Devices Servo units and drives include spindle servo drives and spindle motors, feed servo drives, and feed motors. The servo unit amplifies the weak command signal from the CNC device into a large power signal that controls the drive device, and the drive device turns the amplified command signal into a mechanical motion.
The measuring device includes a position and velocity measuring device, which is necessary for achieving speed closed loop control (spindle, feed) and position closed loop control (feed).
The servo unit, the drive device and the measuring device are collectively referred to as the servo drive system, which is the power device for the machine tool work. The instructions of the CNC device are to be implemented by the servo drive system. Therefore, the servo drive system is an important part of the CNC machine tool.
The main function of the feed servo system is to realize the forming movement of parts processing, and the control amount is speed and position. The main function of the spindle servo system is to achieve the machining movement of the parts, and the control amount is the speed. A common feature of them is the ability to accurately and accurately track the position and speed commands of CNC devices.
In a sense, it can be said that the strength of the CNC machine tool depends mainly on the CNC device. The performance of the CNC machine tool mainly depends on the servo drive system.
5. PLCs, machine tool I/O circuits, and device PLCs (Programmable Logic Controllers) are used to complete the control of sequential operations related to logical operations, which consists of hardware and software.
The machine I/O circuit and device are the executing parts of the A/O control of the CNC machine tool, and are logic circuits composed of relays, solenoid valves, limit switches, and contactors. PLC, machine tool I/O circuit and device complete the following tasks together.
1) Accept the CNC instruction, decode it and convert it into the corresponding control signal, and control the auxiliary device to complete the corresponding switching action of the machine tool.
2) Accept the I/O signals from the operation panel and the machine tool side and send them to the CNC device. After processing them, the output instructions control the operation status of the CNC system and the operation of the machine tool.
6. The machine tool machine is the main body of the numerical control machine tool, and is the controlled object of the numerical control system. It is the executive part that realizes the manufacture and processing. It is mainly composed of main moving parts, feed moving parts (tables, carriages and corresponding transmission mechanisms), supporting parts (pillars, beds, etc.) and special devices (tool automatic exchange systems, automatic workpiece exchange systems) and auxiliary devices. (such as cooling, lubrication, chip removal, indexing and clamping devices, etc.). The composition of the mechanical components of CNC machine tools is similar to that of ordinary machine tools, but the transmission structure is relatively simple, and the requirements for accuracy, stiffness, and shock resistance are high, and the transmission and transmission systems are easy to implement.
Tower Crane Gear means the 19 38 99 teeth gear and the bevel gear, which are the critical parts of the Tower Crane reducer. 19 teeth gear and 38 teeth gear are connected with two motor shaft repectively, which are connected with 99 teeth gear. The speed is reduced by the transmission of gears.
Bevel gear is used for tower crane hoisting reducer.
Tower Crane Gear
Bevel Gear,Tower Crane Sun Gear,Crane Pinion Gear,Tower Crane Transmission Gear,Tower Crane Drive Shaft
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