UAV Magnesium Alloy Motor Mount: 28% Weight Reduction Achieved Through 5-Axis Machining to Meet Flight Duration Requirements

Customer Background

An industrial UAV manufacturer is developing a long-endurance mapping UAV, which is extremely sensitive to weight. The original motor mount was made of aluminum alloy CNC-machined, weighing 42g, and needed to be reduced to within 30g to improve flight duration.

Challenges

• Material Change: Switched to magnesium alloy (AZ91D), which is about 35% lighter than aluminum alloy, but more difficult to machine (easily flammable and prone to deformation)
• Thin-Wall Structure: The motor mount needs to be designed as a hollow thin-walled structure (minimum thickness of 1.2mm) while maintaining sufficient rigidity
• Surface Protection: Magnesium alloy is prone to corrosion, requiring micro-arc oxidation or chemical oxidation treatment

Solutions

• Process Optimization: Used 5-axis CNC machining, with specialized magnesium alloy cutting fluid and compressed air cooling to prevent combustion. Optimized tool paths and layered cutting to reduce deformation
• Post-Treatment: Micro-Arc Oxidation (MAO), with a film thickness of 15μm, passing a salt spray test for 96 hours
• Sample Verification: First produced 2 units for assembly and strength testing, then proceeded to mass production after confirmation

Results

• The final motor mount weighs 28g, achieving a 33% weight reduction compared to the original aluminum alloy solution (client's requirement was within 30g)
• Strength Test: No cracks under 20N·m torque, meeting UAV flight requirements
• Flight duration increased from 32 minutes to 41 minutes, significantly enhancing product competitiveness
• The client will also entrust us with magnesium alloy gimbal brackets and other components in the future

"Yiruida overcame the challenges of magnesium alloy machining, helping us achieve the key goal of UAV lightweighting."