What Is a CNC Machine Tool?

NC machine tool is the abbreviation of Computer numerical control machine tools, which is an automatic machine tool with a program control system. The control system can logically process a program specified by a control code or other symbolic instructions, decode it, express it with a coded number, and enter the numerical control device through an information carrier. After the arithmetic processing, various control signals are sent from 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.

The operation and monitoring of CNC machine tools are all here

The basic composition of a NC machine tool includes a processing program carrier, a NC device, a servo drive device, a machine tool body, and other auxiliary devices. The basic working principles of each component are briefly described below.

Processing program carrier

When the CNC machine tool works, there is no need for workers to directly operate the machine tool. To control the CNC machine tool, it is necessary to

CNC machine tools are

The first

Extend the life of components and wear cycles of components, prevent various failures, and improve the

CNC machine tools were developed by American inventors

CNC machine tools hard bench metal indexable face milling cutters are mainly used for milling planes. When rough milling, choose a smaller cutter diameter because the cutting force is larger during rough milling. Choosing a smaller diameter cutter can reduce the cutting torque. When the CNC machine tool performs fine milling, the diameter of the milling cutter is selected to be larger, and it is best to accommodate the entire width of the surface to be machined to improve the accuracy and efficiency of adding T. When the machine tool machining allowance is large and uneven, the diameter of the tool should be smaller, otherwise, the quality of the workpiece will be affected due to the depth of the hanging knife.

High-speed steel end mills are mostly used for machining bosses and grooves, and are generally not used for machining the surface of the blank-because the hardened layer and sand on the surface of the blank will accelerate tool wear.

When machining the rough surface or rough machining holes, a carbide-filled end mill or a corn mill can be selected for powerful cutting.

When machining the peripheral contour of a flat workpiece, an end mill C is often used.

In order to increase the accuracy of the groove width and reduce the number of tool changes, a milling cutter with a diameter larger than the groove width 7 can be used for processing. The middle part of the groove is milled first, and then both sides of the groove are milled using the tool radius compensation function.

When processing three-dimensional curved surfaces or variable beveled contours, ball-end milling cutters, ring-shaped milling cutters, drum-shaped milling cutters, cone-shaped milling cutters, and disc-shaped milling cutters are often used.

When the machining allowance is small and the surface roughness is high, a face milling cutter with a cubic boron nitride insert or a ceramic insert can be selected to enable high-speed cutting of the machine tool ^[1]

As we all know, high-speed machining technology is developing rapidly, and it is CNC machine tools that promote this development trend. How to properly utilize the performance of CNC machine tools and maintain the accuracy of machine tools is very important.

The power supply is the energy support part to maintain the normal operation of the system. The direct result of its failure or failure is to cause the system to stop or destroy the entire system. In addition, part of the CNC system's operating data, setting data and processing programs are generally stored in the RAM memory. After the system is powered off, it is maintained by the backup battery or lithium battery of the power supply. Therefore, the downtime is relatively long, plugging or unplugging the power supply or memory may cause data loss and make the system inoperable.

At the same time, because the NC equipment uses a three-phase AC 380V power supply, safety is also an important part of the preliminary work of the installation of the NC equipment. Based on the above reasons, the power requirements for the NC equipment have the following requirements:

1. Power grid voltage fluctuations should be controlled between + 10% and -15%. However, China's power supply has large fluctuations and poor quality, and it also hides interference such as high-frequency pulses, plus human factors (such as sudden opening of the brakes). Power failure, etc.). During peak power periods, such as about an hour before or during work during the day and at night, the deviation is often large, even reaching ± 20%. The machine tool is alarmed and cannot work normally, and the power supply system of the machine tool is damaged. It even leads to the loss of related parameter data. This phenomenon has occurred on CNC machine centers or turning centers and other machine tools, and the frequency of occurrence is high, which should be paid attention to.

It is recommended to configure an AC voltage stabilized power supply system with automatic compensation adjustment function in the workshop where the CNC machine tools are more concentrated; a single CNC machine can be equipped with an AC voltage regulator to solve it.

2. It is recommended to connect mechanical electrical equipment to a single power source. If other power sources need to be used to power certain parts of the electrical equipment (such as electronic circuits, electromagnetic clutches), these power sources should be taken as far as possible from components that form part of the mechanical electrical equipment (such as transformers, transducers, etc.). For large and complex machinery, including many machinery working together in a coordinated manner and occupying a large space, more than one attractive power source may be required, which is determined by the configuration of the site power source.

Unless the mechanical and electrical equipment is directly connected to the power source with a plug / socket, it is recommended that the power cord be directly connected to the power terminal of the power disconnect switch. If this is not possible, a separate terminal block should be provided for the power cord.

The handle of the power cut-off switch should be easily accessible and should be installed between 0.6M and 1.9M above the easy-to-operate position. The upper limit is recommended to be 1.7M. This can quickly cut off power in the event of an emergency, reducing losses and casualties.

3. NC equipment requirements for compressed air supply system CNC machine tools generally use a lot of pneumatic components, so the factory should be connected to a clean, dry compressed air supply system network. Its flow and pressure should meet the requirements. The compressed air machine should be installed away from the CNC machine tools. According to the layout of the factory building and the amount of gas used, consideration should be given to installing compressed air in the compressed air supply system network on coal machines, air filters, gas storage tanks, safety valves and other equipment.

4. NC equipment requirements for working environment Precision CNC equipment generally requires constant temperature environment. Only under constant temperature conditions can the accuracy and processing of the machine tool be guaranteed. Generally, ordinary CNC machine tools have no specific requirements for room temperature, but a large number of practices have shown that the failure rate of CNC systems increases greatly when the room temperature is too high.

Humid environment will reduce the reliability of CNC machine tools, especially in humid environments with high acid gas, which will cause corrosion of printed circuit boards and connectors, and increase the electrical failure of machine tools. Therefore, some users in southern China should take measures to dehumidify the environment of CNC machine tools in summer and rainy season.

1) The working environment temperature should be between 0 35 , avoid direct sunlight on the CNC machine tools, and the room should be equipped with good lighting equipment.

2) In order to improve the accuracy of the processed parts and reduce the thermal deformation of the machine tool, if necessary, the CNC machine tool can be installed in a relatively closed factory building equipped with air-conditioning equipment.

3) The relative humidity of the working environment should be less than 75%. NC machine tools should be installed in a place away from liquid splashes and prevent plant leakage.

4) Keep away from excessive dust and corrosive gas environment ^[1] .