Magnesium
Magnesium alloy has extremely low density, light weight, high specific strength, good thermal conductivity and shock absorption, but weak high temperature resistance and wear resistance. It is widely used in aerospace, automotive lightweighting, 3C electronics and precision structural parts.
Processing Options：
- CNC machining
- Laser cutting
- 3D printing
- Surface finish
What is magnesium cnc machining ?
CNC machining of magnesium alloys uses programmed tools to produce lightweight parts with ±0.005mm tolerance. It enables efficient mass production, complex structures, and good surface finish for 3C, automotive, and aerospace uses.
Common magnesium type for cnc machining
AZ91D Magnesium Alloy
Characteristics: High aluminum content (approximately 9%), outstanding strength and hardness, relatively low cost, making it one of the most widely used magnesium alloys. Its Knoop hardness (HK) reaches 76.2, and its corrosion resistance is superior to some aluminum alloys.
AZ31 Magnesium Alloy
Characteristics: Lower aluminum content (approximately 3%), good plasticity, but slightly lower strength and hardness than AZ91D (Knoop hardness HK is 51.1).
ZK60 Magnesium Alloy
Characteristics: High-strength magnesium alloy, suitable for load-bearing structures, good wear resistance, but relatively brittle, making it difficult to process.
Mg-Mn Alloys: Excellent corrosion resistance, suitable for parts in chemical equipment and humid environments.
Mg-RE Alloys: Contain rare earth elements, stable high-temperature performance, used in high-temperature engine components.
Mg-Li Alloys: Extremely low density, the lightest known metallic structural material, suitable for applications where weight is extremely sensitive (such as satellite components).
Surface finish for cnc machining magnesium part
Based on over 15 years of CNC machining experience, we have compiled the following list of surface finish processes used for various precision-machined parts made from magnesium material.
Machined finish
The prototype processed by the machine tool retains traces of tool machining.
Anodizing
Anodizing enhances the corrosion and wear resistance of metals and enables coloring and coating, suitable for metals.
Polish
Polishing enhances surface finish and aesthetic appeal, suitable for materials such as metals, ceramics, plastics, and PMMA.
Sand blasting
Sandblasting involves propelling abrasive material at high pressure or mechanically onto a workpiece to achieve a clean, roughened, and matte finish.
Brushed finish
Brushed finish creates a textured pattern on metal surfaces, enhancing aesthetic appeal. Suitable for aluminum, copper, stainless steel, and other materials.
Powder coating
Powder coating is applied to the workpiece surface via electrostatic adhesion, then cured at high temperatures to form a dense coating, enhancing the corrosion resistance of metal and plastic surfaces.
Electroplating finish
Metal plating is deposited onto material surfaces through electrolytic processes to enhance corrosion resistance and wear resistance. This technique is suitable for metals and certain plastics.
Black oxidize
A black oxide coating is formed on metal surfaces through chemical oxidation, offering low cost, a simple process, and reduced light reflection.
Alodine
Forms a protective coating on surfaces through chemical conversion, enhancing corrosion resistance and adhesion. Environmentally friendly with excellent conductivity, suitable for aluminum and magnesium alloys.
Heat treatment
By altering the internal microstructure of metallic materials through heating, enhances hardness, strength, toughness, and wear resistance. suitable for metals such as steel, aluminum alloys, copper alloys, and titanium alloys.
Advantage of cnc machining magnesium
Lightweight
Magnesium (1.74 g/cm³) is ultra-light, reducing weight and improving efficiency.
Excellent Surface Quality
Low roughness (Ra≤0.8μm) allows direct use, reducing finishing costs.
Excellent Heat Dissipation
High thermal conductivity improves cooling for high-power devices.
Electromagnetic Shielding
Strong EMI shielding, enhanced by CNC precision structures.
High Recyclability
Over 95% recyclable; CNC scraps can be fully reused, eco-friendly.
Application of cnc machining magnesium
3C Electronics: Laptop casings, mobile phone frames, tablet stands.
Automotive Industry: Steering wheel frames, dashboard supports, seat adjustment mechanisms.
Aerospace: Drone arms, satellite structural components, aircraft doors.
Medical Devices: Portable ultrasound machine casings, surgical robot joints.
Sports Equipment:Bicycle frames, golf club heads, carabiners.
FAQ of cnc machining magnesium
How to select appropriate cutting tools and cutting parameters in CNC machining of magnesium alloys?
Recommended tools are fine-grained or ultra-fine-grained carbide (ISO N / K-type) or diamond-coated tools for mass production, with large rake angle (>10°) and clearance angle (>10°) to reduce cutting force and friction. Magnesium alloys support very high cutting speed (>300 m/min), large feed rate (fz > 0.1 mm/tooth), and large depth/width of cut within machine rigidity. The core principle is to maintain high material removal rate while avoiding local heat accumulation, and toolpaths should ensure continuous cutting, minimize air cutting and sudden stops, with roughing focused on efficiency and finishing focused on precision.
What are some common surface treatment methods after CNC machining of magnesium alloys?
Common surface treatments include chemical oxidation for low-cost basic protection, anodizing for improved corrosion and wear resistance, micro-arc oxidation (MAO) for thick ceramic coatings in harsh environments, electroplating (Ni/Cu/Cr) for decorative or functional purposes after proper pretreatment, and advanced self-healing composite oxidation coatings that provide very high corrosion resistance (up to 500–1000 hours salt spray) for high-end applications.
Does CNC machining of magnesium alloys pose safety risks? How can these be mitigated?
Magnesium alloy chips and dust can ignite at high temperature (around 500°C), so wet cutting with emulsion or oil mist is recommended to reduce heat, machines should be equipped with fire suppression and dust collection systems, compressed air should not be used to blow chips, chips must be cleaned regularly, and flame-retardant magnesium alloys (such as Ca/Sr-modified AZ series) should be prioritized to reduce fire risk.
