一、What are lightweight metals?
In the field of materials science and advanced manufacturing, light metals generally refer to metals with a density of less than 4.5 g/cm³. These materials are distinguished not only by their low weight but also by their superior mechanical, electrical, and thermal conductivity, corrosion resistance, and machining qualities. They are therefore vital raw materials for high-end industries like consumer electronics, medical gadgets, aircraft, and new energy vehicles; in particular, they are indispensable in CNC machining.
二、Common lightweight metals
The following types of light metals are frequently used in CNC machining and are extensively utilized in high-end manufacturing industries like aerospace, automotive, electronics, and medicine because of their benefits, which include low density, high strength-to-weight ratio, and exceptional corrosion resistance:
1. Aluminium alloy
Density: around 2.7 g/cm³
Common grades:
6061: Excellent weldability and corrosion resistance; ideal for space, automotive, and aerospace components.
7075: Extremely strong, utilized in defense and aircraft manufacturing.
2024: High fatigue resistance, often used for aircraft skins and structural components.
5052: Superior formability and resistance to seawater corrosion for buildings and ships.
Advantages:
Easy CNC machining
Strong electrical and thermal conductivity
Anodizing or PEO treatment can enhance surface characteristics.
Low cost and recyclable
2. Magnesium Alloys
Density: The lightest structural metal, about 1.7–1.8 g/cm³
Common Grades:
AZ31: Excellent ductility, used for aerospace panels.
AZ91: High strength, excellent die-casting properties, used for electronic enclosures.
ZE41: Strong creep resistance, used for defence and high-temperature components.
Advantages:
Extremely lightweight, delivering significant weight reduction
Excellent vibration resistance and dampening qualities
Outstanding machinability
Considerations:
Flammable (processing must prevent dust explosions)
Corrosion-prone (usually needs protective coatings like PEO)
3. Alloying of titanium
Density: about 4.4-4.5g /cm³ (far lower than steel and with exceptionally high strength, but higher than aluminum/magnesium)
Common brand:
Class 2 (pure titanium): high corrosion resistance, used in chemical and Marine equipment.
Class 5 (Ti-6Al-4V): high strength, good biocompatibility, used in aircraft engines and medical implants.
Class 9 (Ti-3Al-2.5V): good formability, used for aircraft hydraulic lines.
Advantages:
Extremely high ratio of strength to weight
Resistance to corrosion and high temperatures
Outstanding biocompatibility
The challenge:
Processing is challenging (low thermal conductivity, easy hardening).
High costs
Certain cooling techniques and equipment are required.
4. Beryllium (less common but specialised applications)
Density: around 1.85 g/cm³
Advantages:
Exceptionally high rigidity, excellent thermal stability
Used in precision instruments and aeronautical
Limitations:
Toxic dust (needs strict safety precautions)
Highly brittle, costly
Aluminum alloys are therefore the most often used and affordable lightweight metals in CNC machining; magnesium alloys are used in situations needing drastic weight reduction; while titanium alloys serve applications requiring high performance and reliability. Selection necessitates comprehensive consideration of strength, weight, cost, machinability, and operational environment.
三、Main Advantages of Using Lightweight Metals in CNC Processing
1. Superior Cutting Performance
Because of their low cutting resistance and easy chip removal, aluminum and magnesium in particular allow for high-speed processing, greatly increasing the effectiveness of CNC Milling services.
2. High Specific Strength for Supporting Complex Structures
While maintaining strength, they can reduce weight, enabling 5-Axis CNC Milling to produce thin-walled, irregular, and integrated one-piece parts.
3. Excellent Surface Quality and Dimensional Stability
After Precision CNC Turning or High Precision CNC Milling, the part tolerances can reach ±0.005 mm, meeting strict assembly requirements.
4. Compatibility with Various Post-Processing Techniques
Wear resistance and appearance are further improved by processes like shot peening (for titanium), micro-arc oxidation (for magnesium), and anodizing (for aluminum).
5. Support for Green Manufacturing and Circular Economy
In line with the idea of sustainable production, light metal waste may be effectively recycled and reused, which lowers the total cost of bespoke metal fabrication services.
