CNC Machining of Aluminium Alloy
CNC machining of aluminium alloy is a process method that uses digital control technology to precisely machine aluminium alloy materials. Due to the multiple excellent characteristics of aluminium alloy, it has become an ideal material for machining.
This article will introduce CNC machining of aluminium alloy from multiple aspects, including common aluminium alloys for machining, the machining advantages of aluminium alloy, and the application fields of aluminium alloy machined parts.
Benefits of Using Aluminium for CNC Machined Parts
Good Machinability
Aluminium alloy has relatively low hardness, resulting in small cutting force and slow tool wear. This can effectively reduce the frequency of tool replacement, improve processing efficiency, and lower processing costs. Meanwhile, less heat is generated during the cutting process, which is beneficial for maintaining processing accuracy.
High Plasticity and Toughness
Aluminium alloy has good plasticity and toughness. During the CNC machining process, it can withstand significant deformation without cracking, making it suitable for machining various parts with complex shapes and meeting different design requirements.
Low Density
The density of aluminium alloy is approximately one-third that of steel. Being lightweight, it is convenient for processing operations and transportation. For products with weight requirements, such as aerospace and automotive parts, aluminium alloy is an ideal processing material.
Good Surface Quality
After CNC machining, aluminium alloy can obtain a good surface finish. It can meet the surface quality requirements of most products without the need for excessive subsequent processing steps, thus saving processing time and costs.
Strong Corrosion Resistance
A dense oxide film is easily formed on the surface of aluminium alloy, endowing it with good corrosion resistance. It can resist the erosion of the atmosphere, water, and some chemical substances, making it suitable for various harsh working environments and extending the service life of parts.
Good Thermal and Electrical Conductivity
Aluminium alloy has good thermal and electrical conductivity. This is a very important characteristic for some parts that require heat dissipation or electrical conduction, such as heat sinks for electronic devices and electrical connection components.
Recyclability
Aluminium alloy is a recyclable material. Scrapped aluminium alloy parts can be recycled and reused in production through recycling treatment.
Cost-effectiveness
Although the price of aluminium alloy materials themselves may be higher than that of some common steels, due to its good processing performance, during the CNC machining process, it can reduce tool wear, improve processing efficiency, and lower the rejection rate. The comprehensive cost is relatively low. Moreover, the wide application of aluminium alloy ensures an abundant market supply, and the procurement cost is relatively stable.
Common Aluminium Alloys for CNC Machining
Aluminum 6061
Alternative designations: UNS A96061, AlMg1SiCu, A6061, EN AW-6061/AlMg1SiCu, AlMgSi1Cu/3.3211
The main alloys of 6061 are magnesium and silicon, with a small amount of copper, zinc, and other elements.
Due to the presence of silicon, 6061 has moderate hardness, good machinability, relatively low tool wear, and can obtain a better surface finish. It is suitable for various machining processes such as cutting, drilling, and milling.
Aluminum 5052
Alternative designations: A95052
Magnesium is the main alloying element in 5052, with a content of approximately 2.2% – 2.8%, and it also contains a small amount of chromium, manganese, and other elements.
Since 5052 contains magnesium, it has good toughness.
During the machining process, 5052 aluminium alloy is not prone to cracks and brittle fractures. It is suitable for forming processes such as deep drawing and stretching. However, during machining, attention should be paid to controlling the cutting speed and feed rate to prevent excessive heat generation that may cause material deformation.
Aluminum 2024
Alternative designations: A92024, AlCu4Mg1, A2024, 2024(A-USG1)
The main alloying element of 2024 is copper, with a content ranging from 3.8% to 4.9%, and it also contains magnesium, manganese, and other elements.
Due to the relatively high copper content in 2024, its machining difficulty is greater, and it has higher requirements for tools. When machining 2024 aluminium alloy parts, high-performance tools need to be used, and appropriate cutting parameters should be adopted to avoid rapid tool wear and a decline in the surface quality of the machined parts.
Aluminum 6063
Alternative designations: A96063, AlMg0.7Si, A6063, EN AW-6063/AlMg0.7Si, AlMgSi0.5/3.2315
The main alloying elements of 6063 are magnesium and silicon. The silicon content is relatively low, between 0.2% and 0.6%, and the magnesium content is between 0.45% and 0.9%.
6063 has excellent machinability, small cutting resistance, good machining surface quality, and it is easy to obtain high-precision machining dimensions. It is suitable for machining processes such as extrusion and forging and is often used to manufacture various profiles with complex shapes.
Aluminum 7075
Alternative designations: A97075, AlZn5.5MgCu, A7075, EN AW-7075/AlZn5.5MgCu, AlZnMgCu1.5/3.4365
The main alloying elements of 7075 are zinc, magnesium, and copper, with a small amount of chromium and other elements. 7075 is a high-strength aluminium alloy, and its tensile strength can reach more than 572MPa after heat treatment.
The machining of 7075 aluminium alloy is more difficult, and it has high requirements for the hardness, wear resistance, and toughness of the tool. Special cutting processes and parameters, such as a lower cutting speed, a larger feed rate, and appropriate cooling and lubrication measures, need to be adopted to ensure machining quality and tool life.
Some parts with extremely high requirements for material strength and hardness are machined using 7075, such as aircraft landing gears, wing spars, etc. Some high-end sports equipment and molds also use 7075 aluminium alloy.
Compare Aluminum Materials
|
Aluminum Alloy Grade |
Ultimate Tensile Strength (MPa) |
Elongation (%) |
Hardness (HB) |
|
Aluminum 6061 |
290 – 310 |
12 – 25 |
95 – 100 |
|
Aluminum 5052 |
270 – 280 |
20 – 28 |
60 – 65 |
|
Aluminum 2024 |
470 – 520 |
10 – 15 |
120 – 140 |
|
Aluminum 6063 |
180 – 230 |
20 – 30 |
40 – 55 |
|
Aluminum 7075 |
570 – 600 |
5 – 11 |
150 – 160 |
Aluminium CNC Machining Processes
Turning
Turning is a process on a lathe that uses the rotational movement of the workpiece and the linear or curvilinear movement of the tool to change the shape and size of the blank and machine it into a part that meets the requirements.
For the finish machining of the outer circle of aluminium alloy shaft parts, by precisely controlling the lathe speed, feed rate, and cutting depth, the dimensional accuracy and surface roughness of the shaft can be ensured.
Milling
Milling is a method of machining various surfaces on a workpiece using a rotating milling cutter. The rotational movement of the milling cutter is the main movement, and the movement of the workpiece is the feed movement.
In the manufacture of aluminium alloy molds, through milling, mold cavities and cores with different shapes and accuracy requirements can be produced.
Drilling
Drilling is a method of machining holes in solid materials with a drill bit. The drill bit rotates and makes an axial feed movement to drill holes in the workpiece.
It is used to machine holes of various diameters and depths in aluminium alloy parts, such as installation holes and thread bottom holes in aluminium mechanical parts.
Boring
Boring is a method of enlarging, correcting, and finishing an existing hole with a boring tool. The boring tool rotates and makes an axial feed movement simultaneously to improve the dimensional accuracy and shape accuracy of the hole.
Planing
Planing is a method of cutting the workpiece on a planer using a planer tool. The planer tool makes a linear reciprocating movement as the main movement, and the workpiece makes an intermittent lateral or vertical feed movement.
In the machining of aluminium alloy, planing is often used to machine some planes with not too high accuracy requirements, such as the rough machining of aluminium alloy flat plates.
Grinding
Grinding is a method of cutting the surface of a workpiece using a grinding tool (such as a grinding wheel). The abrasive grains on the grinding tool perform micro-cutting on the workpiece surface at high speed, thereby removing excess material and improving the dimensional accuracy and surface quality of the workpiece.
It is often used for the precision machining of aluminium alloy parts, such as grinding the surface of aluminium alloy guide rails to obtain high straightness and surface finish; it can also be used to machine some heat-treated parts of aluminium alloy with higher hardness to ensure their dimensional accuracy and surface quality.
Electrical Discharge Machining
Electrical discharge machining is a processing method that uses pulsed discharge to cause an electro-erosion phenomenon on conductive materials to remove materials.
It is suitable for machining various aluminium alloy parts with complex shapes and high precision requirements, especially those parts that are difficult to machine by traditional cutting methods, such as tiny shaped holes and narrow slots in molds.
Laser Processing
Laser processing is a method of machining aluminium alloy materials using a high-energy-density laser beam. The laser beam is focused on the workpiece surface, causing the material to melt and vaporize rapidly, thereby achieving machining processes such as cutting, drilling, and welding.
In the machining of aluminium alloy, laser cutting is often used to cut various shapes of aluminium alloy sheets, which has the advantages of fast cutting speed, good cut quality, and a small heat-affected zone.
Applications of CNC Machined Aluminium Parts in Industry
Aerospace
Aircraft Structural Parts
Structural parts of aircraft such as wings, fuselage frames, and landing gears often use CNC-machined aluminium parts.
7075 aluminium alloy has high strength and good corrosion resistance. Through CNC machining, complex-shaped structural parts can be manufactured. While ensuring the structural strength of the aircraft, it can effectively reduce the weight of the aircraft, improving fuel efficiency and flight performance.
Engine Components
Some components in aircraft engines, such as impellers and blades, also use CNC-machined aluminium parts.
The good thermal conductivity and corrosion resistance of aluminium alloy enable it to work stably in the high-temperature and high-pressure environment of the engine. Through the high precision of CNC machining, the dimensional accuracy and surface quality of these components can be ensured, thus guaranteeing the performance and reliability of the engine.
Automotive Manufacturing
Engine Blocks and Cylinder Heads
Engine blocks and cylinder heads, which are key components of engines, are made of aluminium alloy and machined by CNC.
The lightweight characteristics of aluminium alloy help to reduce the weight of the engine and improve the fuel economy of the vehicle. At the same time, CNC machining can ensure the high-precision dimensions of the engine block and cylinder head, ensuring the sealing and performance stability of the engine.
Automotive Wheels
Automotive wheels are usually made of 6061 aluminium alloy and other materials through CNC machining. CNC machining can achieve the complex shape design of the wheels to meet the appearance requirements of different vehicle models.
In addition, aluminium alloy wheels are lightweight, which helps to improve the handling and braking performance of the vehicle. Also, their good heat dissipation performance can extend the service life of tires and brake systems.
Body Structural Parts
In order to achieve the lightweight of automobiles, body structural parts increasingly use aluminium alloy materials. For example, aluminium alloy crash beams, body frames, and other components are formed by CNC machining. They can not only effectively absorb collision energy and improve the safety performance of the vehicle but also reduce the body weight, lowering fuel consumption and exhaust emissions.
Electronic Equipment
Housings and Heat Sinks
Housings and heat sinks of electronic equipment such as laptops, mobile phones, and servers often use CNC-machined aluminium parts.
Aluminium alloy has good electrical conductivity, thermal conductivity, and electromagnetic shielding performance, which can effectively protect the internal components of electronic equipment and quickly dissipate heat, ensuring the stable performance of the equipment during long-term operation.
Through CNC machining, beautiful-looking and compact-structured housings and heat sinks can be manufactured to meet the requirements of electronic equipment for lightness and high performance.
Electronic Component Parts
Some parts of electronic components, such as the housings of capacitors and inductors, and the brackets and guide rails inside electronic equipment, also use CNC-machined aluminium parts.
The high-precision machining performance of aluminium alloy can ensure the dimensional accuracy and stability of these parts, meeting the requirements of electronic components for reliability and consistency.
Mold Manufacturing
Injection Molds
In the manufacture of injection molds, aluminium alloy is often used to manufacture some small and precision molds.
6061 aluminium alloy has good machining performance and corrosion resistance. Through CNC machining, the cavities and cores of the molds can be quickly manufactured, shortening the mold manufacturing cycle. At the same time, aluminium alloy molds are lightweight, which is convenient for installation and debugging and is suitable for producing some plastic products with small batches and rapid product replacement.
Die-casting Molds
For some die-casting molds with high heat-dissipation requirements, aluminium alloy is also a commonly used material.
The aluminium alloy die-casting molds manufactured by CNC machining can dissipate heat quickly during the die-casting process, improving the quality of castings and production efficiency.
The cost of aluminium alloy molds is relatively low, which has certain advantages for some small die-casting enterprises or new product development.
Medical Device
Medical Equipment Housings
Housings of medical equipment such as X-ray machines, CT machines, and ultrasonic diagnostic instruments usually use CNC-machined aluminium parts.
Aluminium alloy has good corrosion resistance and biocompatibility and will not have harmful effects on the human body. At the same time, CNC machining can manufacture beautiful-looking and easy-to-clean housings, meeting the requirements of medical equipment for hygiene and aesthetics.
Medical Device Parts
Some parts of medical devices, such as surgical instruments, prosthetics, and orthotics, also use aluminium alloy materials and are manufactured by CNC machining.
The lightweight and high-strength characteristics of aluminium alloy make these medical devices more convenient and comfortable to use. Also, the high precision of CNC machining can ensure the dimensional accuracy and fit accuracy of the parts, improving the performance and reliability of medical devices.
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