Key point: CNC machine tools have advantages in processing accuracy, automation level, production efficiency, labor intensity, and other aspects that ordinary machine tools cannot match. However, the cost of purchasing CNC machine tools, especially large CNC machine tools, is very high, which often makes many users hesitant, especially in developing countries like China where funds are limited. Therefore, most mechanical factories want to buy but cannot afford CNC machine tools. How to obtain CNC machine tools with relatively little investment is a question worth exploring. Can we upgrade and transform the existing machine tool into a CNC machine tool without buying one? The answer is affirmative. The experience of upgrading and renovating over the past few years has shown us that this is very promising. It not only has good practical performance and short cycles, but also can save a lot of money. The larger the machine tool being modified, the more funds are saved. CNC machine tools have advantages in processing accuracy, automation level, production efficiency, labor intensity, and other aspects that ordinary machine tools cannot match. However, the cost of purchasing CNC machine tools, especially large CNC machine tools, is very high, which often makes many users hesitant. Especially in developing countries like China, where funds are limited, most mechanical factories want to buy but cannot afford CNC machine tools. How to obtain CNC machine tools with relatively little investment is a question worth exploring. Can we upgrade and transform the existing machine tool into a CNC machine tool without buying one? The answer is affirmative. The experience of upgrading and renovating over the past few years has shown us that this is very promising. It not only has good practical performance and short cycles, but also can save a lot of money. The larger the machine tool being modified, the more funds are saved. The following is an example of CNC remanufacturing carried out by our company: Z-axis modification of the right tool holder. Replace the original trapezoidal screw (63) with an imported Rexroth ball screw × ten × Remove the light bar drive (3600 mm) and add a servo motor drive to scrape the z-axis guide rail and the z-axis pressure plate and strip. Design and manufacture electrical control systems for machine tools. Select Fanuc 0it CNC system and Fanuc AC digital servo motor. Design and develop machine tool control logic diagram using domestic joint venture low-voltage electronic control components. Finally, perform electromechanical joint debugging on the machine tool. Debugging the x-axis and z-axis movements of the machine tool, adjusting the geometric accuracy of the machine tool, adjusting the coordinate accuracy of the machine tool, and using dual frequency laser to detect the accuracy of each axis. Perform machine tool auxiliary function debugging and continuously idle the machine tool for 36 hours. After the transformation, the performance of the machine tool is stable and reliable. After more than a year of production verification, it meets the requirements of the transformation. The renovation cost of 1 million yuan is only equivalent to 1/15 of the purchase of CNC machine tools, saving users a lot of money. This machine tool has contributed greatly to the production of volutes in hydroelectric equipment for the factory, creating a value of tens of millions of yuan. What are the issues to pay attention to when upgrading to CNC? What kind of machine tools are suitable for CNC upgrading and remanufacturing? Experience has proven that the transformation effect of upgrading vertical and horizontal lathes (especially large vertical and horizontal lathes), gantry milling to CNC gantry milling, gantry planer to CNC gantry milling, horizontal boring and milling machine to CNC horizontal boring and milling machine, and vertical and horizontal grinding machine to CNC grinding machine is relatively ideal. The upgrading and transformation of CNC must first redesign and remanufacture the mechanical parts of the machine tool to meet the requirements of CNC. Simply adding servo motors and CNC systems is not enough to achieve the goal of upgrading. Therefore, the following work generally needs to be done: replacing the original trapezoidal screw with a ball screw, improving accuracy, reducing friction, grinding and scraping the guide rail, and pasting plastic, or directly using linear rolling guide rails to refine the spindle system, improving spindle accuracy, and designing an automatic cooling and chip removal system, When it is necessary to improve the automation level of machine tools, it is necessary to add a tool changing mechanism - the design and manufacturing of an automatic lubrication system for the tool magazine manipulator. During the renovation, it is necessary to determine and select the CNC system and servo system. The more functions a CNC system has, the better. Systems with more functions are generally more expensive. Choose domestic and imported systems as needed. There is still a gap between domestically produced systems and imported systems, and it is generally better to choose imported systems for large high-precision equipment. But in recent years, domestic systems have made significant progress and can be reliably used for general lathes and milling machines. Firstly, choose an AC servo motor as the servo motor. The selection of a CNC upgrade contracting company for remanufacturing is also very important. To choose a company that has undergone qualification certification, the current remanufacturing industry is still very non-standard. The cost of retrofitting the same machine tool varies greatly among different companies, sometimes up to 2-3 times. The existing performance of the contracting company needs to be inspected on-site by the contracting company. Companies without a fixed site and a stable technical team cannot engage in remanufacturing. A good remanufacturing enterprise must have strong mechanical and electrical design capabilities, as well as certain processing and manufacturing capabilities.