With the rapid development of the new energy vehicle industry, lightweight and integrated chassis components have become the core research and development direction for automakers. Parts such as aluminum alloy integrated chassis brackets, steering knuckles, and battery frame connectors have complex structures, featuring numerous holes, end faces, arcs, threads, and other characteristics. Traditional single-function machine tool processing with separate steps has issues such as cumbersome processes, long turnaround times, poor consistency in accuracy, and high labor costs. A precision parts manufacturing enterprise in the Pearl River Delta region has undertaken several designated processing projects for chassis components of new energy vehicle manufacturers, fully introducing a turn-milling CNC machining center to reconstruct the production process and achieve integrated processing of all parts steps. This has significantly improved production capacity and quality, creating a benchmark case of efficient CNC production in the new energy automotive parts field.

This project primarily focuses on processing two major types of products: aluminum alloy steering knuckles and chassis integrated brackets for new energy vehicles, using 6061-T6 aviation-grade aluminum alloy as the raw material. These components play crucial roles in vehicle load-bearing, steering, and shock absorption, requiring not only precise dimensions but also good structural strength and surface quality. The workpieces encompass more than ten processing features such as external circles, internal holes, irregular surfaces, inclined holes, threads, and flat surfaces. Traditional production methods involve sequentially using over four machines including lathes, milling machines, drilling machines, and tapping machines, with repeated disassembly and transportation of the workpieces. The cumulative clamping times for a single set of products can exceed six times. Frequent clamping is prone to generating positioning errors, leading to excessive form and position tolerances such as coaxiality and perpendicularity. Additionally, the process connection takes a long time, resulting in a buildup of work-in-process on the production line, which cannot meet the automotive companies' requirements for large quantities and short delivery times.

To overcome production bottlenecks, the enterprise's technical team decided to adopt a turn-milling CNC machine tool as the main production equipment and redesign the overall process route. The turn-milling machine tool integrates all machining functions such as turning, milling, drilling, tapping, chamfering, etc., and supports the linkage between the spindle and the power turret, enabling all machining processes of the workpiece to be completed in a single setup. After the project was initiated, the technical staff first completed the overall process layout based on the 3D drawings of the parts, planning the cutting sequence according to the principle of "roughing before finishing, surface machining before hole machining". Utilizing the multi-station chuck and tailstock structure of the equipment, stable clamping of the workpiece was achieved, eliminating the need for secondary disassembly throughout the entire process. Considering the cutting characteristics of aluminum alloy materials, the spindle speed, feed rate, and cutting depth were optimized. Coupled with a high-pressure air cooling dust removal system, aluminum chips were prevented from adhering to the surfaces of the workpiece and cutting tools, ensuring the surface finish of the machined parts.

For mass production needs, the production line is equipped with automated loading and unloading robots and material conveyor lines simultaneously, creating a CNC automation unit. The robots are responsible for loading raw materials, unloading finished products, and transferring workpieces. The machine tools operate continuously according to preset programs, enabling 24-hour unattended production. At the same time, each turn-milling CNC equipment is connected to the workshop MES production management system, which uploads production data, equipment status, processing quantity, abnormal alarms, and other information in real time. Management personnel can remotely monitor the operation of the entire production line, facilitating production scheduling and equipment maintenance. In terms of quality control, the enterprise adopts a combination of first-piece full inspection, patrol inspection and sampling inspection, and finished product full inspection, equipped with precision calipers, micrometers, and three-coordinate measuring machines, to strictly control form and position tolerances and appearance quality, ensuring consistent quality across each batch of products.

After the project transformation was completed and officially put into operation, production data was significantly optimized. Taking the steering knuckle of new energy vehicles as an example, the traditional multi-equipment division of labor process took 90 minutes to process a single piece. After adopting the integrated machining of turning and milling CNC, the processing time for a single piece was shortened to 28 minutes, and the production efficiency was increased by nearly 220%. The number of workpiece clamping times was reduced from 6 times to 1 time, and the positioning error was significantly reduced. The product form and position tolerance pass rate was increased from 85% to 99.5%. At the same time, the automated production line reduced on-site operating personnel by 80%, significantly reducing labor costs. The workshop's inventory of work in process was reduced by 70%, and the delivery cycle was shortened by half, fully meeting the daily supply demand of tens of thousands of parts for automobile companies.

As of now, this CNC milling and turning automated production line has been operating stably for three years, serving more than ten mainstream new energy vehicle and supporting component enterprises, with an annual production capacity exceeding 3 million pieces. This engineering case proves that the milling and turning CNC machining technology perfectly fits the production needs of integrated components for new energy vehicles. The integrated machining mode not only solves the pain points of low precision and slow efficiency in traditional processes, but also enhances the market competitiveness of enterprises. Against the backdrop of the continuous expansion of the new energy vehicle industry, this production mode of "milling and turning CNC + automated production line + digital management" has been referenced and applied by many auto parts processing enterprises, becoming a classic reference case for small and medium-sized manufacturing enterprises to transform, upgrade, and improve quality and efficiency.