The coordinated optimization of material selection and heat treatment significantly enhances strength. For aluminum alloy CNC processing, 7075-T651 sheet was selected, and through solution treatment and artificial aging treatment, the yield strength reached 503MPa (62% higher than the cast state). The processing case of Boeing 787 wing rib components shows that the CNC milling of T7451 in the heat-treated state has a residual stress elimination rate of over 85%, and the fatigue life has been increased to 1.2×10⁷ cycles (only 6.5×10⁶ cycles for untreated parts). Further, work hardening is inhibited through low-temperature cutting (-50℃ cold air), and the surface microhardness gradient fluctuation is controlled within ±5HV0.3.
Fiber streamline control enhances structural integrity. Five-axis linkage processing keeps the Angle between the forging streamline direction of 7075 alloy and the principal stress axis ≤15°, reducing the standard deviation of tensile strength from 38MPa in traditional processing to 19MPa. The test data of the Airbus A350 support shows that for components precisely mished along the grain direction, the ultimate load reaches 142kN (23% higher than the vertical direction), and the failure displacement increases by 41%. The topological optimization weight reduction design reduces the stress concentration coefficient from 2.7 to 1.3, and the maximum deformation is reduced by 0.12mm under the same load.
Surface modification technology enhances fatigue performance. Micro-arc oxidation (MAO) generates a 30μm ceramic layer on the surface of the 2024-T3 alloy, with a microhardness of 1500HV (130HV for the substrate). After this treatment, the salt spray test corrosion resistance time of the helicopter rotor connection parts has been extended to 1,500 hours (only 500 hours for anodizing), and the rotational bending fatigue limit has increased by 27%. The introduction of a 0.2mm residual compressive stress layer in shot peening has extended the crack initiation life of the landing gear actuator cylinder by 3.8 times.
Precise dimensional control optimizes the load distribution. CNC machining of aluminum alloy achieves a coaxiality of 0.02mm for the bearing housing hole (5 times better than turning), and reduces the vibration amplitude by 40% after assembly. Tests on wind turbine gearboxes show that when the flatness of the planetary carrier support surface is machined to 0.03mm/400mm, the area of gear contact marks increases by 58%, and the pitting failure rate drops from 12% to 1.7%. The thickness tolerance of the thin-walled parts (1.5mm) is controlled within ±0.05mm through constant force milling technology, and the stiffness dispersion is reduced by 63%.
Residual stress engineering enhances dimensional stability. Liquid nitrogen deep cryogenic treatment (-196℃×8 hours) reduces the peak residual stress of the 6061-T6 component from 218MPa to 43MPa. The case of vacuum chambers for semiconductor equipment has confirmed that the flatness drift after this process is less than 3μm/m (up to 15μm in conventional processing), and the deformation is reduced by 82% at a working temperature of 150℃. Vibration stress relief technology enables the stress relief rate of the medical CT frame to reach 92%, and the median deformation value during long-term use is only 0.008mm.
The comprehensive application verification of strength gain shows that the Formula 1 steering knuckle is made of aluminum alloy through CNC processing. Topology optimization reduces weight by 41% while increasing stiffness by 25% (finite element analysis shows that the maximum stress is reduced by 37%). The crash test data shows that the electric vehicle battery box treated with T6 and micro-arc oxidation has a deformation of only 3.2mm (9.7mm for die-cast parts) under an impact energy of 7.8J/cm², and the probability of puncture risk has dropped from 18% to 0.3%. These data confirm that through the triple optimization of materials, structure and process, aluminum cnc machining has brought about a qualitative leap in the load-bearing capacity of aluminum alloy components.