Technical characteristics of CNC milling machine

Focusing on the requirements of quality, efficiency and technological change, my country's machinery manufacturing process equipment-mainly CNC equipment, has undergone profound changes at the technical level. The functions of CNC milling machines are constantly enriched, using process, process centralization and compound technology; machine tools have new developments in structural layout and new material applications; CNC technology is open, intelligent, networked, high-speed and high-precision New developments have been achieved. The purpose is to improve production efficiency, improve accuracy, ensure quality and maximize efficiency.

　　Continuous pursuit of high quality and high efficiency is the eternal theme and goal of machinery manufacturing research, and is the source of power to promote the development of its process equipment. Technological requirements and changes are the basis and foundation for the development and innovation of mechanical manufacturing process equipment technology.

　　Domestic CNC milling machines have gone through a long period of 50 years of development, and have achieved rapid development in the past 10 years. In particular, they have received the attention of the government and set up major technical research projects to effectively promote the development of CNC machine tools.

At present, domestic CNC milling machines are available for more than 1500 varieties, covering CNC metal cutting machine tools, CNC sheet metal processing machine tools (CNC stamping machine tools, CNC laser processing machine tools, flame cutting machine tools, etc.), CNC electrical processing machine tools, industrial robots, three coordinates Measuring machines are basically complete. In 2010, the number of CNC metal cutting machine tools was about 1.5 million (of which more than 400,000 were imported). The annual output of metal cutting machine tools alone exceeded 160,000. From January to October 2011, it reached a total of 218,000 units. It can reach about 250,000 units. The number and value of domestic brand CNC milling machines account for more than 50% of the domestic market. New progress has also been made in five-axis linkage and compound machining centers, CNC systems and other supporting technical products that represent advanced technology. This article focuses on the development and gap of CNC technology.

What are the technical characteristics of CNC machine tools? CNC machine tools have advantages over ordinary machine tools in terms of processing accuracy, degree of automation, production efficiency, labor intensity, etc., but the cost of buying CNC machine tools, especially large CNC machine tools, is very high, which often makes many users frightened, especially Developing countries like China have limited funds, so most machinery factories want to buy CNC machine tools but cannot afford them.

　　How to obtain CNC machine tools with relatively little investment is a question worth discussing. Can you upgrade the original machine tool without buying a CNC machine tool and turn it into a CNC machine tool? The answer is yes. The experience of upgrading and transformation in the past few years tells us that this is promising, not only with good practical performance and short cycle time, but also can save a lot of money. The larger the machine tool being transformed, the more money is saved. The following is an example of CNC remanufacturing conducted by a company:

　　Reform the z axis of the right tool post. Replace the original trapezoidal lead screw (63×10×3600mm) with imported Rexroth ball screws, remove the light rod drive, and increase the servo motor drive to repair the z-axis guide rail to repair the z-axis pressure plate and inserts.

　　Design and manufacture of machine tool electronic control system. The FANUC 0it numerical control system is selected. The FANUC AC digital servo motor is selected. The domestic joint venture low-voltage electronic control components are used to design and develop the control logic diagram of the machine tool.

　　 Finally, the electromechanical joint debugging of the machine tool. Debug the machine tool's x-axis and z-axis movements. Debug the machine tool's geometric accuracy. Debug the machine tool's coordinate accuracy. Use dual-frequency laser to detect the accuracy of each axis. Carry out machine tool auxiliary function debugging and run the machine for 36 hours of continuous idling.

　　 After the transformation, the machine performance is stable and reliable. After more than one year of production verification, it meets the transformation requirements. The renovation cost of 1 million yuan is only equivalent to 1/15 of the purchase of CNC machine tools, which saves a lot of money for users. The machine tool has made great efforts to produce volutes in the hydropower equipment of the plant, creating an output value of tens of millions of yuan.

The problems that need to be paid attention to in CNC upgrade, what kind of machine tool is suitable for CNC upgrade and remanufacturing? Experience has shown that vertical and horizontal lathes (especially large vertical and horizontal lathes), gantry milling upgrade CNC gantry milling, gantry planing upgrade CNC gantry milling Horizontal boring and milling machine upgrade CNC horizontal boring and milling machine, vertical and horizontal grinder upgrade CNC grinder transformation effect is ideal.

　　CNC upgrade must first redesign and re-manufacture the machine part of the machine to make it meet the requirements of CNC. Simply adding servo motor and CNC system can not achieve the purpose of upgrading. Therefore, the following work is generally done:

Replace the original trapezoidal lead screw with a ball screw to improve accuracy, reduce friction, grind and scrape the guide rails and paste or directly use linear rolling guide rails to refine the spindle system, improve the accuracy of the spindle, design an automatic cooling and chip removal system, and increase the degree of machine automation. Increase the tool change mechanism-the automatic lubrication system designed and manufactured by the tool magazine manipulator.

　　The CNC system and servo system should be determined and selected during the transformation. The function of the numerical control system is not as much as possible, and the system with more functions is generally more expensive. The domestic system and the imported system should be selected according to the needs. At present, there is still a gap between the domestic system and the imported system. It is generally better to choose the imported system for large-scale high-precision equipment. However, the domestic system has made great progress in recent years, and can be used reliably for general lathes and milling machines. The servo motor first selects the AC servo motor.

　　 is also very important for the choice of remanufacturing CNC upgrade contractors. To choose a company that has passed the qualification certification, the current remanufacturing industry is still very irregular. The price of different companies for the same machine tool transformation is very different, sometimes up to 2-3 times. Companies that do not have a fixed site and a stable technical team cannot do remanufacturing. A good remanufacturing enterprise must have strong mechanical and electrical design capabilities and certain processing and manufacturing capabilities.