Case Background: Challenges in Machining Complex and Precision Metal Molds
A professional mold manufacturing enterprise undertook an order for metal molds supporting the production of automotive parts. The structure of these molds is extremely complex, featuring numerous intricate curved surfaces, narrow slots, and thin-walled structures, imposing stringent requirements on the mold's precision, surface quality, and production cycle. The critical dimensional accuracy of the molds is required to reach ±0.01mm, the surface roughness needs to be controlled below Ra0.4μm, and the customer demands delivery within a short time frame.
Equipment Selection and Configuration: The enterprise introduced a five-axis 联动 high-speed machining center. This machine is equipped with a high-precision numerical control system, boasting fast computing and precise control capabilities, enabling complex trajectory movements with multi-axis linkage. Meanwhile, the spindle of the machine tool has high-speed (up to 40,000r/min) and high-torque characteristics, capable of meeting the needs of different materials and processing technologies. In addition, it is equipped with an advanced tool system, including high-performance milling cutters, boring cutters, etc. The precision and durability of the tools are carefully selected to ensure the stability and high precision of the machining process.
Process Planning and Programming: Professional CAD/CAM software is utilized for 3D modeling and machining process planning of the molds. According to the structural characteristics of the molds, detailed machining procedures are formulated, including rough machining, semi-finishing, and finishing. In the rough machining stage, efficient cutting strategies are adopted to quickly remove most of the excess material while ensuring the stability of the machining process and tool life. The semi-finishing stage further optimizes the shape and dimensional accuracy of the molds, laying a good foundation for the finishing stage. In the finishing stage, leveraging the advantages of five-axis linkage, special tool path planning methods such as spiral milling and contour milling are employed to achieve high-precision machining of complex curved surfaces and fine structures. Programmers generate precise CNC machining programs in the CAM software and verify and optimize the programs through the simulation function to ensure the accuracy and safety of the machining process.
Machining Process Control: During the machining process, the operation status of the machine tool, including spindle speed, feed rate, tool position, and other parameters, is monitored in real-time through the numerical control system. Sensors equipped on the machine tool are used to monitor factors such as vibration and temperature during machining. Once an abnormal situation is detected, the system automatically adjusts the machining parameters or pauses the machining immediately to avoid machining errors or tool damage. At the same time, an advanced cooling and lubrication system is adopted to ensure that the machining area is fully cooled and lubricated, reducing the cutting temperature and improving tool life and machining surface quality.
Remarkable Application Achievements
Precision Enhancement: Through the high-precision machining of CNC machine tools, the critical dimensional accuracy of the molds is stably controlled within ±0.01mm, fully meeting the design requirements. The contour accuracy of complex curved surfaces has been significantly improved, and the surface roughness has reached Ra0.3μm, far exceeding the customer's requirement of Ra0.4μm. This effectively enhances the molding quality of the molds and the surface finish of the products, providing a guarantee for the high-quality production of automotive parts.
Efficiency Improvement: Compared with traditional machining methods, the automated machining and efficient cutting strategies of CNC machine tools have greatly shortened the machining time. The mold machining tasks that originally took several weeks to complete can now be delivered in about one week, increasing the production efficiency several times over. At the same time, due to the reduction of manual intervention and clamping times, the machining errors and scrap rates caused by human factors are reduced, further improving production efficiency and economic benefits.
Cost Reduction: Although the procurement cost of CNC machine tools is relatively high, in the long run, their high-efficiency machining capabilities and low scrap rates reduce the comprehensive production cost. On the one hand, it reduces the waste of raw materials and rework costs; on the other hand, the shortened production cycle accelerates capital turnover and improves the market competitiveness of the enterprise. In addition, the maintenance cost of CNC machine tools is relatively low, and the operation is simple, with relatively low technical requirements for operators, which also reduces labor costs to a certain extent.