Detailed explanation of cooling system of CNC machining center
According to its function, the cooling system of CNC machining center is mainly divided into two parts: the cooling of machine tools and the cooling of tools and workpieces during cutting.
1. Machine cooling and temperature control
CNC machining center is a kind of machine tool with high precision, high efficiency and high investment cost, so in order to recover the wood as early as possible in the factory. Give play to its role. It is generally required to work continuously for 24 hours. In order to ensure the consistency of the machining accuracy of the machine tool working for a long time, the working stability of the electrical and control systems, and the service life of the machine tool, the machining center has corresponding requirements for the ambient temperature and the heating cooling and temperature control of all parts.
The environment temperature has a noticeable influence on the machining accuracy and working stability of the machining center. For the machining with high precision requirements and high dimensional consistency requirements for the curtain batch parts, the constant temperature of the working environment of the machining center shall be maintained. For general machining centers (closed loop control, the minimum resolution is 0.001 mm), the requirements for working environment overflow are 0-451, and the ambient temperature change is not greater than 1.1 min,
The electronic control system of CNC machining center is the control core of the whole machine tool. Its reliability and stability during operation play a decisive role in the normal operation of the machining center, and most of the components in the electric control system will generate heat when energized Without adequate heat dissipation, the temperature of the whole system is likely to be too high, which affects its reliability, quality and component life The electric control system of the machining center generally adopts the method of installing heat sink on the components with high heat and adopting forced circulation ventilation of fan to expand the glue. Reduce the temperature of the entire electronic control system However, this method has the disadvantages of dust easily entering the control box, poor stability of overflow control, and wet air easily entering. Therefore, on some high-end machining centers, special electric cabinet air conditioners are generally used to adjust the temperature of the electric control system.
Figure 5-4 shows the schematic diagram and structure diagram of the electric cabinet air conditioner. Its working principle is: the external air of the electric cabinet air conditioner passes through the condenser, absorbs the heat of the high-temperature air from the compressor in the condenser, and cools the hot air in the electric cabinet In this process, the liquid coolant in the evaporator becomes a low temperature and low pressure gaseous refrigerant, which is then inhaled and compressed by the compressor into a high temperature and high pressure gaseous refrigerant to complete a cycle. At the same time, the hot air in the electric control cabinet circulates through the evaporator
The water vapor is cooled Condensed into liquid water and discharged, so that the hot air can get the dry rice after cooling. In the mechanical body of the machining center, the main shaft components and transmission mechanism are the most important heat source For parts such as main shaft bearing and transmission gear, especially the main shaft bearing with medium or above pre tightening, if the temperature is too high during operation, it is easy to cause scuffing damage, lubricating oil viscosity reduction and other consequences. Therefore, the upper shaft components and transmission device of the machining center are usually equipped with a working temperature control device
VP1050 machining center uses a dedicated spindle overflow controller to control the working temperature of the spindle.
Figure 5-5a shows the working principle diagram of the upper shaft temperature controller. The circulating hydraulic pump 2 extracts the lubricating oil (L-AN32 engine oil) from the upper shaft head through the pipe 6 and sends it to the upper shaft head through the filter 4. The temperature sensor 5 detects the overflow of the lubricating oil and transmits the temperature price number to the temperature controller control system. The control system controls the start and stop of the cooler according to the preset value of the operator on the temperature controller The working state of the cooling and lubrication system is detected by the pressure relay 3, and this evaluation number is transmitted to the PLC of the CNC system. The CNC system takes the normal lubrication of the spindle drive system and the spindle as a necessary and sufficient condition for the spindle system to work. If the pressure relay 3 does not send a signal, the CNC system P sends an alarm evaluation number, and the spindle is prohibited from starting. Figure 5-Sb shows the operation panel of the temperature controller The operator can set the difference between oil temperature and room temperature, and the temperature controller will control according to this difference. The panel is equipped with multiple indicators such as circulating hydraulic pump, cooler operation and fault For operators to identify the working state of the temperature controller. The spindle drive system with high load in the spindle head is cooled simultaneously with the spindle.
2. Workpiece cutting cooling
A large amount of cutting heat is generated when the CNC machining center conducts high-speed and high-power cutting, which makes the temperature of the tool, the workpiece and the internal machine tool rise, thus affecting the tool life and the accuracy of the machine tool with workpiece processing quality. Therefore, good workpiece cutting cooling is of great significance in T-adding center The cutting fluid not only cools the tools, workpieces and machine tools, but also lubricates, removes chips and cleans up, and prevents rust between the tools and workpieces. Figure 5-6 shows the schematic diagram of the workpiece cutting cooling system of H400 machining center During the operation of H400 machining center, cutting fluid can be sprayed from two pipes according to the requirements of the processing program. When cutting fluid is not required The cutting fluid can be turned off via the cutting fluid ON/OFF button. Generally, the cutting fluid switch command will be added to the program code generated by CAM. During manual processing, the cutting fluid on/off button on the machine tool operation panel can start the cutting fluid motor and send out the cutting fluid. In order to fully improve the cooling effect In some machining centers, the spindle and the tool are cooled by means of water supply in the center of the spindle and internal cooling of the tool This method has a good effect on improving the tool life, giving play to the good cutting performance of the machining center, and the smooth discharge of chips, especially in deep hole age dyeing, so! I The former application is more and more extensive
In fact, it is difficult to solve the problem of whether a three-axis CNC machining center is better or a four-axis machining center is better. There is only a problem that is not suitable for machining some kinds of parts. Basically, all three-axis machining centers can process the parts that can be processed by a four axis machining center, while the parts that can be processed by a four axis machining center may not be processed by a three-axis machining center.
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