Six CNC main parts of CNC machine system
1. Programming and program carrier
The CNC program is composed of the work instructions required by the CNC machine tool to automatically process the parts, including the necessary mechanical movement during the cutting process, the outline size of the part, process parameters, and other processing information. The work of programming can be done manually or by using a computer outside the CNC machine tool. Automatic programming system to complete. For parts with relatively simple geometric shapes, there are not many program segments, and manual programming can be used; for more complex parts, especially spatial surface parts, because manual programming is cumbersome, time-consuming, and error-prone, automatic programming is required.
2. Input device
The function of the input device is to convert the numerical control code information on the program carrier into the corresponding electrical pulse signal and transmit it to the memory of the numerical control device. Depending on the program control medium, the input device can be an optoelectronic reader, a recorder, or a floppy disk drive. Use a photoelectric reader to read the punched tape, and then use a large number of tape drives and floppy disk drives. Some CNC machine tools do not use any program storage carrier, but the content of the program list is manually input through the keyboard on the CNC device. Also. The CNC program can be directly transmitted from the programming computer to the CNC device by communication.
The numerical control device is the core of the numerical control machine tool, including the microcomputer, various interface circuits, display, and other hardware and corresponding software. It can complete information input, storage, transformation, interpolation calculation, and various control functions. CNC device accepts input devices The sent pulse signal, after compilation, calculation, and logic processing outputs various signals and instructions to control each part of the machine tool and realizes the prescribed and orderly actions according to the program requirements. These control signals are: Command signals for feed displacement, feed direction, and speed; command signals for variable speed, reversing, and start and stop of main moving parts; tool command signals for selection and exchange of tools; control cooling and lubrication start and stop, workpiece and machine tool parts loose Auxiliary signals such as opening, clamping, indexing table indexing, etc.
The functions of the numerical control device are:
①Multi-coordinate control;
②Realize the interpolation of multiple functions;
③Information conversion function, such as inch/metric conversion, coordinate conversion, absolute value/incremental value conversion;
④Compensation function, such as tool radius Compensation, length compensation, transmission gap compensation, and pitch error compensation;
⑤A variety of processing method options, such as various processing cycles, and repeated processing;
⑥ With fault self-diagnosis function;
⑦Communication and networking functions, etc.
4. Power control device
The power control device is a control system between the CNC device and the machine tool machinery and hydraulic components. Its main function is to receive the spindle speed change, reversing, start or stop, tool selection and replacement, and indexing table output from the CNC device. The signals of auxiliary operations such as the indexing and locking of the workpiece, the clamping or loosening of the workpiece, the opening or closing of the cutting fluid, etc., after the necessary compilation, logic judgment, and power amplification, directly drive the corresponding actuators (such as electrical appliances, hydraulics, Pneumatic and mechanical components, etc.) to complete the actions specified in the instruction, so as to realize all the automatic operations of the CNC machine tool in the processing process.
5. Servo control device
The servo system mainly completes the motion and motion control of the machine tool (including feed motion, spindle motion, position control, etc.). It consists of a servo drive circuit and a servo drive motor and forms the CNC machine tool with the executive components and mechanical transmission components on the machine tool. Feed system. It receives the position control information from the numerical control device, converts it into the corresponding coordinate axis feed movement and precise positioning movement, and drives the machine tool actuator to move. Because it is the last control link of the CNC machine tool, its performance will be It directly affects the production efficiency, machining accuracy, and surface quality of CNC machine tools.
6. Mechanical parts of machine tools
Compared with traditional ordinary machine tools, the mechanical parts of CNC machine tools have several characteristics:
(1) The high-performance spindle and feed servo drive are adopted, the mechanical transmission structure is simplified, and the transmission chain is shorter.
(2) The mechanical structure has high dynamic characteristics, dynamic stiffness, damping stiffness, wear resistance, and thermal deformation resistance.
(3) More efficient transmission parts are used, such as ball screw nut pairs, linear rolling guides, etc.
(4) There are also some supporting components (such as cooling, chip removal, protection, lubrication, lighting, storage, transportation, etc.) and auxiliary equipment (programming machine and tool setting instrument, etc.)
