In the “heart” of new energy vehicles – the drive motor system – the two mirror-polished motor housings shown in the image are the core precision components that bear the power operation. They are not only the “armor” protecting the internal windings and rotor of the motor, but also the key structures that ensure heat dissipation efficiency and operational stability. From an aluminum alloy ingot to the final high-gloss finished product, the processing process is an ultimate test of precision and craftsmanship.
I. Raw Material: Starting with Rigorous Material Selection
We use 6061-T6 aluminum alloy, a material that combines lightweight, high thermal conductivity, and excellent mechanical strength, making it the ideal base material for new energy vehicle motor housings. Before processing, the raw material undergoes solution treatment and artificial aging to stabilize the hardness in the HB90~110 range, ensuring plasticity during cutting and avoiding subsequent deformation risks. Each ingot must pass ultrasonic flaw detection to ensure that there are no internal pores, cracks, or other inherent defects, laying a solid foundation for subsequent processing.
II. CNC Rough Machining: Efficient Removal of Excess Material
The first step in processing is rough milling on a five-axis machining center. We use a large-feed milling strategy, using carbide rough milling cutters, with a spindle speed of 12000 r/min and a feed rate of 800 mm/min, to quickly remove more than 70% of the excess material. To prevent the workpiece from being affected by thermal deformation, high-pressure cooling emulsion is continuously sprayed during processing to control the cutting temperature within 40℃. After rough machining, the geometric tolerance of the housing is left with a 0.5mm machining allowance, providing sufficient space for semi-finishing and finishing.
III. Semi-Finishing: Sculpting Contour Precision
In the semi-finishing stage, we switch to high-precision end mills, focusing on machining the mounting datum surface, bearing seat holes, and heat dissipation channels. At this stage, the spindle speed is increased to 18000 r/min, and the feed rate is reduced to 300 mm/min. By optimizing the tool path, the geometric tolerance is controlled within 0.1 mm. For the complex curved surfaces of the housing, the five-axis linkage system enables dynamic adjustment of the tool posture, ensuring a smooth transition of the flow channel surface and laying the foundation for contour accuracy in subsequent high-gloss machining.
IV. High-Gloss Finishing: The Birth of a Mirror-Like Texture
High-gloss finishing is the core process that gives the housing a mirror-like effect. We use PCD (polycrystalline diamond) tools, with a hardness exceeding HV10000, enabling nano-level cutting. When machining the end face and inner bore, the spindle speed soars to 35000 r/min, the feed rate is only 50 mm/min, and the single-tool cutting depth is controlled within 0.02 mm. This ultra-precision cutting method ensures a surface roughness Ra value of less than 0.05 μm, creating a mirror-like reflective effect. This not only enhances the aesthetic appeal of the component but also reduces the surface friction coefficient and optimizes the heat dissipation efficiency inside the motor.
V. Inspection and Post-Processing: The Final Guardian of Quality
After machining, a coordinate measuring machine performs a full inspection of the key dimensions of the housing, including the roundness of the bearing seat hole (≤0.005 mm), end face runout (≤0.008 mm), and other geometric tolerances. Subsequently, the housing enters the ultrasonic cleaning station to remove residual cutting fluid and aluminum chips, and then is dried with high-pressure air. Finally, anodic oxidation treatment is performed, forming a 10 μm thick hard oxide film on the surface, significantly improving its corrosion resistance and wear resistance, ensuring long-term stable operation under complex working conditions.
From the efficient and robust rough machining to the delicate and meticulous high-gloss finishing, every process embodies the wisdom of precision manufacturing. These motor housings, gleaming with metallic luster, are not only a manifestation of industrial aesthetics but also a solid guarantee for the reliable operation of new energy vehicle power systems.