Aluminum's low density, useful mechanical properties, corrosion resistance, and machinability keep it relevant for CNC machined parts. Aluminum also has an established role in electrical systems, electronics, machinery, and other manufacturing sectors.
The use of aluminum in CNC machining also depends on the alloy and the part requirements. This article looks at why aluminum is used for CNC machining parts, which industries are driving its use, which aluminum alloy families matter for CNC work, and where CNC machining fits when parts start as castings, forgings, or extrusions.
Why Aluminum Is Used for CNC Machined Parts
Aluminum combines low density with a range of useful mechanical properties across different alloy and temper conditions. Many aluminum alloys also have favorable machining characteristics.
Lightweighting and Strength-to-Weight Requirements
Aluminum has a density of about 2.70 g/cm³, while aluminum alloy density varies with composition. Its low density makes it useful when component weight matters. Aluminum alloys also provide different strength levels, so the selected alloy and temper determine the material strength available for the design.
Machinability for Precision Features
Many aluminum alloys machine readily. Machinability includes factors such as cutting force, chip form, tool wear, and surface quality, not simply how easily the material cuts. These factors affect the aluminum CNC machining process used to produce controlled features.
Aluminum does not have one uniform machining behavior. Alloy composition, temper, and microstructure can affect machining characteristics. Good machinability can support CNC machining of controlled features, but it does not by itself guarantee dimensional accuracy. The final result also depends on the machining setup, tooling, workholding, and other process conditions.
Which Industries Use Aluminum CNC Machined Parts
Aerospace Industry
Aerospace aluminum CNC parts for flight and test hardware. These include machined aluminum patch bodies for space instruments, aluminum retainers for aerospace test rigs, and other precision-machined components used in space-flight work.
Automotive Industry
In automotive machined aluminum parts in engine, transmission, brake, and suspension systems. Parts such as pump housings, clutch retainers and pistons, control arms, knuckles, master cylinders, pinion housings, brake calipers, oil pans, and flywheel spacers.
Medical Equipment Industry
Medical equipment can use machined aluminum for structural and mechanical components. Examples include machined aluminum frames for robotic surgical equipment, machined 6061 aluminum hardware for image-guided medical systems, and CNC-machined aluminum master molds used to produce microfluidic splitter devices.
Electrical and Electronic Equipment
Electrical instruments can also use machined aluminum components. electric-field measurement instrument uses machined aluminum structural plates, a lid, a top plate, a bottom plate, and aluminum standoffs. A technical device uses custom machined-aluminum holders to interface a microchip with a coating setup.
Aluminum Alloys Used in CNC Machined Parts
CNC machined aluminum parts can use different alloy series because all aluminum alloys do not have the same material properties. The 6xxx, 2xxx, and 7xxx series provide different options when the part needs a specific combination of strength, corrosion resistance, and machining characteristics.
6xxx Series Aluminum
The 6xxx series uses silicon and magnesium as its main alloying elements. These alloys provide moderately high strength and good corrosion resistance. 6061 is a 6xxx alloy commonly used for machined aluminum parts.
The temper also changes the properties of 6061. For example, 6061-O, 6061-T4, and 6061-T6 show different strength levels. The specific temper therefore matters when the part has defined material requirements.
2xxx and 7xxx Series Aluminum
The 2xxx series uses copper as its principal alloying element and provides high strength and toughness. These alloys have lower atmospheric corrosion resistance than many other aluminum alloys. 2024 is a common example of this series. The 7xxx series uses zinc as its primary alloying element and can provide very high strength. 7075 is a high-strength 7xxx alloy.
The alloy and temper also affect machining behavior. Machining data show differences among 2024-T4, 6061-T6, and 7075-T6, including differences in chip behavior. Different tempers of the same alloy can also have different machinability.
CNC Machining for Cast, Forged, and Extruded Aluminum Parts
Cast, forged, and extruded aluminum parts can start close to the required shape, but the forming process may not create every finished feature. CNC machining can add the detail and precision that the starting shape does not provide.
Cast Aluminum Parts
Casting can provide the basic part shape while machining adds detail and tighter-tolerance features. Aluminum castings can also go through CNC milling and turning when the finished part requires close tolerances.
Forged Aluminum Parts
Forging can bring aluminum close to the required shape, which can reduce later machining. Machining can serve as a secondary operation when the forging requires additional machining to achieve the required shape, precision, or surface finish. Some precision aluminum forgings need little subsequent processing.
Extruded Aluminum Parts
Extrusion creates a profile, while CNC machining can add holes, slots, and other functional features. Drilling, tapping, milling, and turning can be used on aluminum extrusions, and more complex parts can use CNC machining after simpler fabrication processes.
Conclusion
Aluminum CNC machined parts make sense when the selected alloy, part requirements, and machining process fit the job. Cast, forged, and extruded aluminum can reduce the amount of material removal, but CNC machining may still be needed for final features and precision.
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