1. What Is Aluminum, and Why Is It Commonly Used for Machined Parts?
For many custom parts, the best material is not simply the hardest one or the cheapest one. What matters is whether it matches the part’s actual structure and intended use. Aluminum stands out because it is a lightweight metal with good machinability, low density, solid corrosion resistance, and strong versatility across applications.
Aluminum also offers favorable cutting performance. It is widely used in milling, drilling, tapping, pocket machining, and contour machining. This gives it a high degree of flexibility in CNC precision machining projects. For prototype parts, low-volume custom parts, and components with more complex geometries, aluminum usually delivers stable and reliable machining performance.
2. Common Aluminum Grades Used in Machining
6061
6061 is one of the most commonly used aluminum grades in machining. It offers a well-balanced combination of strength, machinability, and corrosion resistance, which makes it suitable for a wide range of applications. It is a common choice for general structural parts, brackets, mounting plates, housings, and functional components.
6063
6063 is more often used for parts with higher requirements for appearance and surface finishing results. It is commonly selected for applications where a better surface condition and more consistent anodizing performance are important. For certain cosmetic parts, profile-based structural parts, and components with larger visible surfaces, 6063 can offer clear advantages.
7075
7075 is a high-strength aluminum alloy suited to parts with greater strength requirements. It is often used in structural components that must withstand higher loads or deliver stronger mechanical performance. Even so, cost, machining behavior, and post-treatment requirements usually need to be evaluated in the context of the specific project.
2024
2024 offers relatively high strength and is commonly found in some aerospace-related applications. However, its corrosion resistance is comparatively moderate, so in practical use it is usually selected with the operating environment and post-finishing requirements in mind.
5052
5052 is more commonly used in plate-based applications and offers good corrosion resistance. It is suitable for certain housings, covers, and sheet-like parts. For projects that need a balance of basic strength and corrosion resistance, 5052 may also be a good material option.
3. What Types of Machined Parts Commonly Use Aluminum?
Common aluminum machined parts include housings, brackets, mounting plates, covers, connectors, frame components, heat sinks, and various custom structural parts. For projects that require weight reduction without sacrificing essential strength, aluminum is often a very practical choice.
In automation equipment and robotics projects, aluminum is frequently used for support parts, connecting structural components, mounting bases, and lightweight parts. In electronics and equipment accessories, it is also common in housings, panels, heat-dissipation structures, and cosmetic components. For prototype work and custom development projects, aluminum is often prioritized because of its efficient machining performance and broad adaptability.
4. What Should Be Considered When Machining Aluminum Parts?
- Aluminum surfaces are more likely to show light scratches and pressure marks. This is especially important for appearance-critical parts, where surface protection needs closer attention during clamping, handling, deburring, and before and after finishing.
- Thin-wall structures are more prone to deformation. For aluminum parts with deep cavities, thin walls, or heavy material removal, poor toolpath planning, clamping strategy, or stock allowance control may lead to distortion during machining or dimensional variation after stress release.
- Burr control and edge refinement are often necessary after machining. Small burrs can easily appear around hole openings, corners, slots, and areas near threads. If the part will later be anodized, bead blasted, or given another surface treatment, the initial surface condition becomes even more important.
- Functional areas such as threads, mating surfaces, locating holes, and assembly surfaces also require a balance between machining efficiency and dimensional consistency. Although aluminum is easy to cut, complex part geometry still requires a well-planned process to achieve the desired final result.
5. Common Surface Finish Options for Aluminum Parts
Common surface finish options for aluminum parts include As Machined, Sanding, Bead Blasting, Anodizing, Brushed Finish, Polishing, and Powder Coating. Different finishes suit different project goals.
6. Overview of Common Aluminum Grades and Typical Uses
| Aluminum Grade | Main Characteristics | Typical Uses |
| 6061 | Well-balanced overall performance, good machinability, good corrosion resistance | Brackets, mounting plates, housings, structural parts |
| 6063 | Better surface quality, suitable for certain cosmetic parts and anodizing | Cosmetic parts, profile components, visible-surface parts |
| 7075 | High strength | High-strength structural parts, load-bearing components |
| 2024 | Relatively high strength | Certain high-performance structural parts, aerospace-related components |
| 5052 | Good corrosion resistance, suitable for plate applications | Covers, housing panels, some structural plate parts |
7. Common Surface Finishes for Aluminum Parts and Their Purposes
| Surface Finish | Main Purpose |
| As Machined | Retains the machined condition, offers high efficiency, and keeps cost relatively low |
| Sanding | Reduces light tool marks, smooths edges, and improves tactile feel |
| Bead Blasting | Creates a more uniform matte texture |
| Anodizing | Improves corrosion resistance and enhances appearance |
| Brushed Finish | Produces a linear textured look |
| Polishing | Increases surface gloss |
| Powder Coating | Adds protection and provides color coverage |
8. Conclusion: Why Aluminum Is Such a Common Material in Machining
For machined parts, aluminum is a practical material that balances weight, machinability, application range, and post-finishing flexibility. It is suitable for many common structural parts, as well as selected cosmetic and functional components, which is why it is so widely used in custom CNC machining projects.