What is cnc machine?
CNC machine tool is the abbreviation of Computer numerical control machine tools, which is an automatic machine tool equipped with a program control system. The control system can logically process programs with control codes or other symbolic instructions, decode them, express them in coded numbers, and input them into the numerical control device through the information carrier. After calculation and processing, various control signals are sent by the numerical control device to control the movement of the machine tool, and the parts are automatically processed according to the shape and size required by the drawing.
CNC machine tools solve complex, precise, small-batch, and multi-variety parts processing problems. It is a flexible, high-efficiency automatic machine tool that represents the development direction of modern machine tool control technology. It is a typical mechanical and electrical integration. chemical products.
What are 3 types of CNC machines?
There are many types of CNC machine tools, and CNC machine tools can be classified according to different methods: classification by process use, classification by motion control mode and servo control mode, etc.
—Classified by processing technology
- 1# General CNC machine tools
- This type of machine tool is the same as the traditional general-purpose machine tools, including , milling, boring, drilling, grinding machines, etc., and there are many types of each type, such as vertical milling, horizontal milling, tool milling, etc. in machines. Longmen milling and so on. The process possibilities of this type of machine tool are similar to those of general-purpose machine tools, the difference is that it can process parts with complex shapes.
- 2# Multi-coordinate CNC machine tools
- Some parts with complex shapes cannot be processed by three-coordinate CNC machine tools, such as the processing of propellers and aircraft curved surface parts, etc., which require a synthetic motion of more than three coordinates to process the desired shape. As a result, multi-coordinate CNC machine tools have emerged, which are characterized by the number of axes controlled by the CNC device and the structure of the machine tool is relatively complicated. The number of coordinate axes usually depends on the process requirements of the processed parts. CNC machine tools with 4, 5, and 6 coordinates are commonly used now.
- 3#CNC machining center machine tools
- This type of machine tool is developed on the basis of general CNC machine tools. It is a CNC machine tool with an automatic tool changer (also known as a multi-process CNC machine tool or boring and milling machine tool) composed of an additional tool magazine (which can accommodate more than 10-100 tools) and an automatic tool changer on a general CNC machine tool. This kind of machining center is customarily referred to as a machining center——Machining Center), which makes the CNC machine tools develop further in the direction of automation and high efficiency.
—Classified by machine tool motion
According to the trajectory of the relative movement between the tool and the workpiece that can be controlled, CNC machine tools can be divided into point control CNC machine tools, point line control CNC machine tools, contour control CNC machine tools, etc.
- 1#Point control CNC machine tool
- The CNC system only controls the exact position of the tool from one point to another point, but does not control the motion trajectory. The motion between the coordinate axes is irrelevant, and the workpiece is not processed during the movement. Such CNC machine tools mainly include CNC drilling machines, CNC coordinate boring machines, and CNC punching machines.
- 2#Linear control of CNC machine tools.
- In addition to controlling the exact position between points, the CNC system must also ensure that the movement trajectory between two points is a straight line, and also control the movement speed, also known as point-to-point linear control. Such CNC machine tools mainly include relatively simple CNC lathes, CNC milling machines, and CNC grinding machines. CNC machine tools that are purely used for linear control are rare.
- 3#Contour control CNC machine tools
- The feature of contour control is that it can control the displacement and speed of two or more motion coordinates simultaneously and continuously. It not only controls the starting and end coordinates of the moving parts of the machine tool, but also controls The speed, direction and displacement of each point in the entire processing process are also called continuous control CNC machine tools. Such CNC machine tools mainly include CNC lathes, CNC milling machines, CNC wire cutting machines, machining centers, etc.
—Classified by machine tool control mode
- 1#Open-loop control CNC machine tools
- This type of machine tool does not have a position detection feedback device, and usually uses a stepping motor as the actuator. After the input data is calculated by the numerical control system, a pulse command is issued to make the stepper motor rotate through a step angle, and then converted into a straight line movement of the worktable through a mechanical transmission mechanism. The moving speed and displacement of the moving parts are determined by the frequency of the input pulse and determined by the number of pulses.
- 2#Semi-closed-loop control of CNC machine tools
- install detection elements (such as inductive synchros or photoelectric encoders) at the end of the motor or the end of the screw, and indirectly detect the displacement of the moving part by detecting its rotation angle, and then feed back to the CNC system. Since most of the mechanical transmission links are not included in the system closed-loop loop, more stable control characteristics can be obtained. Although its control accuracy is not as good as that of closed-loop control CNC machine tools, it is more convenient for debugging, so it is widely used.
- 3#Closed-loop control CNC machine tools
- This type of CNC machine tool is equipped with a position detection feedback device. The position detection feedback device adopts a linear displacement detection element, which is directly installed on the moving parts of the machine tool, and the measurement results are directly fed back to the CNC device. Through the feedback It can eliminate transmission errors in the entire mechanical transmission chain from the motor to the moving parts of the machine tool, and finally achieve precise positioning.
How to use a cnc machine?
CNC lathes are one of the most widely used equipment in the manufacturing industry, so they are also relatively common equipment. In essence, a CNC lathe can use one or more tools to process raw materials. When using a CNC lathe, the tool operates according to the contents of the program written and uploaded to the machine, resulting in high-precision and repeatable production.
CNC lathes can not only control precise cutting or other processing positions by using the coordinate system, but also control the rotational speed and tool feed rate according to the material of the workpiece to achieve flexible processing and the desired shape. The following will briefly introduce the operation method of CNC lathe and the operation skills of CNC lathe.
- 1# Program editing: Before processing the workpiece, it is necessary to compile the processing program of the workpiece. If the processing program of the workpiece is long or complicated, it is not necessary to program on the CNC lathe, and manual programming or programming machine programming can be used, so that it can avoid It takes up the time of the CNC lathe, thus increasing the auxiliary time of processing.
- 2# Start up and transfer to the processing program: first turn on the main power supply, so that the CNC lathe has the conditions to start up. Turn on the button with the key, and after the CNC system and the CNC lathe are powered on at the same time, check the status of each part of the lathe and other auxiliary equipment. According to the medium of the program, it can be input by programming machine or serial port communication.
- 3# Workpiece installation alignment and starting coordinate feed: put the workpiece on the workbench, perform installation alignment, align the tool setting point to the initial point of the program, and align the tool benchmark. When continuous processing is carried out, the processing program in the memory is generally used, which has a lower failure rate than the processing program on the tape. When processing a workpiece, you can press the feed hold button to pause the feed action, and observe the processing situation. After confirming that it is correct, press the cycle start button to resume the feed action.
- 4# Workpiece detection and removal: After the program ends, if the program needs to be saved, it can be stored in the memory of the CNC system, or the program in the memory can be output to an external device for storage. When the workpiece is still clamped in the chuck, the size of the workpiece should be detected. If the size of the workpiece does not meet the processing requirements, it is necessary to properly compensate the tool and reprocess the workpiece. When the workpiece size is qualified, the workpiece can be disassembled.
- 5# Shutdown: Before shutting down, pay attention to check the condition of the CNC lathe and the position of each component. Then turn off the power and system power of the CNC lathe, and finally turn off the total power.
What is a cnc machine used for?
CNC machine tools are the product of the combination of machine tool processing technology and electronic computer technology. It makes the production of many fine parts and mechanical components that are difficult to produce easier and more intelligent. As an emerging modern technology, CNC machine tools have unparalleled advantages and have brought revolutionary changes to the traditional manufacturing industry. They are the vitality of the modern machinery manufacturing industry and become a symbol of industrialization. It has brought an important impact on people’s production and life. Specifically, CNC machine tools are mainly used in the following fields:
- 1# Application in industrial production
- CNC machine tools are widely used in industrial production, which greatly speeds up the efficiency of industrial production and improves the quality of industrial products. In the specific industrial production process, the computer program code is input into the computer, so that there are specific programs to realize the automation of production.
- 2# Application in the automotive industry
- With the continuous development of the economy, my country’s automobiles have accelerated the pace of development to meet the needs of modern development and the actual needs of international competition. How to improve the device configuration of auto parts has become the key to the production of various automobile companies. In the field of cars, the production cycle of annual production of hundreds of thousands of vehicles is about ten seconds, and multi-variety processing is one of the key issues that must be solved for car equipment. This increase in production levels was made possible by the advent of CNC machine tools.
- 3# Application in aviation
- With the acceleration of the globalization and regionalization of the world economy, the technological competition among countries is becoming more and more fierce, and the development of the aviation industry has also become an important part of it. The development and application of CNC machine tool technology has led to a new round of development in the aviation industry of various countries.