Numerical control device

The numerical control device is the core of a numerical control machine tool. Modern numerical control devices all adopt the form of CNC (computer numerical control). This CNC device generally uses multiple microprocessors to realize numerical control functions in the form of programmed software, so it is also called software NC. CNC system is a kind of position control system. It interpolates the ideal motion track according to the input data and then outputs it to the execution part to process the required parts. Therefore, the numerical control device is mainly composed of three basic parts: input, processing, and output. All these works are reasonably organized by the system program of the computer so that the whole system can work harmoniously.

1. Input device: input the CNC command to the CNC device, and there are different input devices according to different program carriers. It mainly includes keyboard input, disk input, cad/cam system direct communication input, and DNC (direct numerical control) input connected to the superior computer. At present, many systems still retain the paper tape input form of the photoelectric reader.

• Paper tape input mode. The part program can be read by the paper tape photoelectric reader to directly control the movement of the machine tool, or the content of the paper tape can be read into the memory, and the part program stored in the memory can be used to control the movement of the machine tool.

• MDI manual data input mode. The operator can use the keyboard on the operation panel to input the instructions of the processing program, which applies to relatively short programs. Under the edit status of the control device, the processing program is input with software and stored in the memory of the control device. This input method can reuse the program. This method is generally used for manual programming. On the CNC device with a session programming function, different menus can be selected according to the problems prompted on the display, and the machining program can be automatically generated by inputting the relevant dimension numbers through man-machine dialogue.

• DNC direct numerical control input mode is adopted. The part program is saved in the upper computer, and the CNC system receives the subsequent program segments from the computer while processing. DNC mode is mostly used for complex workpieces designed by cad/cam software and directly generating part programs.

2. Information processing: the input device transmits the processing information to the CNC unit, compiles it into information that can be recognized by the computer, and the information processing part gradually stores and processes it according to the provisions of the control program, and then sends position and speed commands to the servo system and the main motion control part through the output unit. The input data of the CNC system includes part contour information (start point, end point, straight line, arc, etc.), machining speed, and other auxiliary machining information (such as tool change, speed change, coolant switch, etc.). The purpose of data processing is to complete the preparation before interpolation operation. The data processing program also includes tool radius compensation, speed calculation, and auxiliary function processing.

3. Output device: the output device is connected to the servo mechanism. The output device receives the output pulse of the arithmetic unit according to the command of the controller and sends it to the servo control system of each coordinate. After power amplification, it drives the servo system to control the machine tool to move according to the specified requirements.

Main drive system

It is one of the main components that transmit torque during machining. It is generally divided into two types: gear step-less speed regulation and electrical step-less speed regulation. Higher grade CNC machine tools require step-less speed regulation to meet the requirements of various processing technologies. It is mainly composed of a spindle drive control system, spindle motor, and spindle mechanical transmission mechanism.

Strong current control cabinet

It is mainly used to install various electrical components for strong current control of the machine tool. In addition to providing input power for weak current control systems such as numerical control and servo, as well as various electrical protections such as short circuit, overload, and Undervoltage, it mainly acts as a bridge between the output interface of PLC and the electrical execution components of various auxiliary devices of the machine tool, that is, controlling various AC motors of auxiliary devices of the machine tool The solenoid valve or electromagnetic clutch of the hydraulic system mainly plays the role of expanding contact dispersion and contact capacity.

In addition, it is also connected with the relevant manual control buttons on the machine tool console. The strong current control cabinet is composed of various intermediate relays, contactors, transformers, power switches, wiring terminals, and various electrical protection components. It is similar to ordinary machine tools electrically. However, to improve the anti-interference of the weak current control system, it is required that all kinds of electromagnetic induction devices such as motors and contactors that are frequently started or switched must be connected to RC resistance-capacitance absorbers in parallel, and the input of various detection signals shall be connected with shielded cables.

Auxiliary devices

It mainly includes ATC cutter automatic exchange mechanism, APC workpiece automatic change mechanism, the workpiece clamping, and loosening mechanism, rotary workbench, hydraulic control system, lubrication device, and overload and limits protection function, etc. The machining function of the machine tool is different from that of the Xing type, and the parts it contains are also different. Auxiliary devices are necessary supporting devices to ensure the full play of the functions of CNC machine tools. Common auxiliary devices include pneumatic and hydraulic devices, chip removal devices, cooling and lubrication devices, rotary worktable and CNC dividing head, protection, lighting, and other auxiliary devices.

Machine tool body

It refers to the mechanical structure entity of CNC machine tools. Compared with traditional ordinary machine tools, it is also composed of the main transmission mechanism, feed transmission mechanism, workbench, bed, and column. However, great changes have taken place in the overall layout, appearance modeling, transmission mechanism, cutter system, and operating mechanism of CNC machine tools. The purpose of this change is to meet the requirements of numerical control technology and give full play to the characteristics of numerical control machine tools.

The machine tool host is the main body of the CNC machine tool. It includes a machine bed, base, column, beam, sliding seat, worktable, headstock, feed mechanism, tool rest, automatic tool changing device, and other mechanical parts. Ti Hao machinery is the main product of the company, which takes rotary center, lead screw, shaft processing, CNC lathe processing, tool handle, toolbar, and collet extension bar as main products. It is the mechanical part that automatically completes various cutting processes on CNC machine tools. Compared with traditional machine tools, the main body of CNC machine tools has the following structural characteristics:

1. The new structure of machine tools with high rigidity, high seismic resistance, and small thermal deformation is adopted. Generally, the stiffness and seismic resistance of the machine tool host are improved by improving the static stiffness of the structural system, increasing the damping, and adjusting the quality and natural frequency of the structural parts, so that the machine tool host can meet the needs of continuous and automatic cutting of the NC machine tool. The influence of thermal deformation on the main machine can be reduced by improving the structural layout of the machine tool, reducing heating, controlling temperature rise, and adopting thermal displacement compensation.

2. High-performance spindle servo drive and feed servo drive devices are widely used to shorten the transmission chain of CNC machine tools and simplify the structure of the mechanical transmission system of machine tools.

3. The transmission device and moving parts with high transmission efficiency, high precision, and no clearance are adopted, such as ball screw nut pair, plastic sliding guide rail, linear rolling guide rail, hydrostatic guide rail, etc.