What are the composition and working steps of CNC machine tools?

What are the components of CNC machine tools? What are its working steps? For people who use CNC machine tools, these must be understood and mastered, and they are also basic. Only when you have mastered it, can you use CNC machine tools correctly, and there will be no problems such as improper operation. Now we will introduce the knowledge of these two aspects. as follows. 1. The composition of CNC machine tools CNC machine tools are composed of programs, input/output devices, CNC units, servo systems, position feedback systems, and the machine body. Let's briefly introduce them below. (1) CNC unit The CNC unit is the core of the numerically controlled machine tool. The CNC unit is composed of three parts: information input, processing and output. The CNC unit accepts digital information, decodes, interpolates, and logically processes through the control software and logic circuit of the numerical control device, and then outputs various instruction information to the servo system, which drives the executive components for feed motion. Others include the speed change, direction change and start and stop signals of the main moving parts; tool command signals for selecting and exchanging tools, start and stop of cooling and lubrication, work and machine parts loosening, clamping, indexing table indexing, etc. Command signals, etc. (2) The servo system is composed of a driver and a drive motor, and is combined with the execution parts and mechanical transmission parts on the machine tool to form the feed system of the CNC machine tool. Its function is to convert the pulse signal from the numerical control device into the movement of the moving parts of the machine tool. For a stepper motor, each pulse signal makes the motor rotate through an angle, which in turn drives the moving parts of the machine tool to move a small distance. Each execution component of the feed motion has a corresponding servo drive system, and the performance of the entire machine tool mainly depends on the servo system. (3) Position feedback system The feedback of the angular displacement of the servo motor and the displacement feedback of the CNC machine tool actuator (worktable). Including gratings, rotary encoders, laser rangefinders, magnetic grids, etc. The feedback device converts the detection result into an electrical signal and feeds it back to the numerical control device. Through the comparison, the deviation between the actual position and the command position is calculated, and the deviation command is issued to control the feed movement of the execution component. (4) Mechanical components of machine tools For CNC machine tools such as machining centers, there are also parts such as tool magazines for storing tools, manipulators for exchanging tools, etc. The composition of mechanical components of CNC machine tools is similar to that of ordinary machine tools, but the transmission structure requirements are simpler. Accuracy, rigidity, shock resistance and other aspects are more demanding, and its transmission and speed change systems are more convenient for automatic expansion. 2. The working steps of CNC machine tools The machining parts on the CNC machine tools must go through the following steps: (1) In the preparation stage, determine the relevant processing data (tool path coordinate points, machining cutting amount, tool size information according to the drawings of the processed parts) Etc.), select other auxiliary information according to the process plan, the selected fixture, the type of tool, etc. (2) In the programming stage, according to the processing technology information, use the language recognized by the CNC system of the machine tool to write the CNC processing program (description of the processing technology process), and fill in the program sheet. (3) Prepare the information carrier. According to the compiled program list, store the program on the information carrier (perforated tape, magnetic tape, disk, etc.), and transmit all processing information to the numerical control system through the information carrier. If the CNC machining machine tool is connected to the computer, the information can be directly loaded into the CNC system. (4) When the program is executed in the processing stage, the machine tool numerical control system decodes and calculates the processing program statements and converts them into action instructions to drive each moving part. Under the unified coordination of the system, it drives the timely movement of each moving part to automatically complete the workpiece Processing. Generally speaking, a CNC machine tool is to compile the information related to the processed parts with a code composed of prescribed text, numbers and symbols in a certain format into a processing program list, and input the processing program into the CNC device through the control medium. After analysis and processing by the numerical control device, various signals and instructions corresponding to the processing program are issued to control the machine tool for automatic processing. 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