CNC machining, also known as computer numerical control machining, is a precision manufacturing process that uses computer programming tools to machine aluminum into complex parts. This process is great for aluminum because it cuts the tough yet soft metal well, producing parts with excellent durability, excellent strength-to-weight ratio and high dimensional accuracy.Through CNC machining processes, aluminum can be leveraged for a wide range of applications, including precision machined medical devices, automotive parts that require strength, and aircraft parts that must be lightweight. Aluminum is a material that is valuable to many industries. There are some important design considerations for CNC machining aluminum parts:

Consideration 1: Wall Thickness

Maintaining proper wall thickness is critical for strength and stability, as aluminum is a relatively thin material that can easily deform. Wall thickness plays a vital role in CNC machined aluminum parts for the following reasons:

Strength and Stability: Aluminum bends and warps under pressure, especially when it is thin, although it is strong despite its weight. By maintaining proper wall thickness at all times, ensure that the part can withstand expected loads and machining forces without deformation.
Tool Reach and Accessibility: CNC tools can be difficult to reach and penetrate thin walls. Some internal cavities or features may become inaccessible due to limited clearance. This can result in incomplete machining or require specialized small tools, which can be expensive and inefficient.
Chip Accumulation and Heat Dissipation: During machining, aluminum chips or chips accumulate around the cutting tool. Thin walls reduce the space available for chip evacuation, increasing the risk of clogging and overheating. This can lead to part failure, machining accuracy issues, and tool damage. Additionally, thin walls have a reduced ability to dissipate heat generated during machining, which increases the potential for part deformation and tool wear.
Cost and material efficiency: Thicker walls inherently require more material, but building walls that are too thick also wastes resources and increases production costs. For cost-effective CNC machining, an ideal balance must be found between adequate strength and efficient material use.
Maintain design intent: Walls that are too thin can compromise design intent and require redesign or alternative manufacturing techniques to accommodate essential features such as threaded holes or intricate details.

Consideration 2: Features and Tolerances

Design elements that affect cost and viability include undercuts, sharp corners, and tight tolerances, which may call for specialized tools or processes. Why are tolerances and features so important? Let’s delve into the reasons:

  • Machinability: Aluminum has peculiarities despite its versatility. The CNC tools may have difficulty navigating intricate details, thin walls, and sharp corners. Creating features that are simple to machine not only speeds up production but also lowers tool wear and tear, which saves money.
  • Precision Matters: Even though CNC machines are precision experts, they have their limitations. Miniscule permitted variations in dimensions, or tight tolerances, can be difficult to attain and greatly raise production costs.
  • Think Assembly: When designing an aluminum part that must work well with others, assembly features must be taken into account. An easy and effective assembly process is ensured by design elements like threaded holes, slots, and interlocking tabs that blend in seamlessly with other parts.
Aluminum Parts

Consideration 3: Draft Angles

Tiny draft angles on vertical features facilitate part removal from the mold and help to keep it from jamming. Draft angles are crucial for CNC machining aluminum parts for several reasons:

  • Part Removal: Vertical walls or cavities are a common feature of aluminum parts. In the absence of draft angles, these characteristics would function as hooks, tightly grasping the mold and making it challenging, if not impossible, to remove the completed part without breaking it or the mold.
  • Reduced Risk of Damage: The force exerted upon extracting a part devoid of draft angles may result in rips, rips, or distortions. This can jeopardize the part’s dimensional accuracy and is especially harmful to surface finishes. Draft angles ensure the part maintains its intended form and finish by reducing friction and the resulting damage risk.
  • Tool Wear and Efficiency: Attempting to extract a jammed part can significantly strain the machining instruments. This quickens the deterioration of tools, raising production costs overall and possibly necessitating tool replacements. By making part removal easier, lessening the strain on the tools, and increasing their lifespan, draft angles help avoid such situations.
  • Cost-Effectiveness: The budget and deadlines can be greatly affected by production delays resulting from problems with part removal and frequent tool replacements.

Consideration 4: Material Selection

Based on the required levels of corrosion resistance, machinability, and desired mechanical properties, select the appropriate aluminum alloy. Material selection is crucial for CNC machining aluminum parts for several reasons:

  • Impact on Machinability: The ease of cutting, chip formation, and tool wear of various aluminum alloys vary. Selecting the appropriate alloy reduces tool wear and guarantees a smooth, efficient machining process, all of which have an impact on production costs and schedule.
  • Desired Mechanical Properties: Specific strength, stiffness, weight, and ductility are required for the finished part. These qualities can be found in varying combinations in different alloys. Selecting the incorrect alloy could result in parts that are too heavy, too brittle, or too ductile for the intended use.
  • Corrosion Resistance: Corrosion resistance may be crucial, depending on the environment in which the part is intended to be utilized. Certain aluminum alloys are more naturally resistant to corrosion than others. Selecting the appropriate alloy guarantees that the part won’t break down over time, particularly in challenging conditions.
  • Cost and Availability: A variety of alloys differ in price and accessibility. Although certain high-performance alloys have better qualities, their costs may be much higher or their lead times may be longer.
  • Design Flexibility: Some alloys are more suited for intricate features and complex geometries because of their ductility and machinability.
Aluminum Parts


When CNC machining aluminum parts, design factors are crucial because they impact the part’s machinability, the precision of the machining process, and the production cost. Designers can make sure that their parts are affordable to produce, easy to machine, and meet the necessary specifications by carefully taking these factors into account. Rapid prototyping, precision parts, tooling machining, and end-use parts are just a few of the CNC machining parts that Proto MFG can provide for you as one of the top suppliers of precision CNC machining services in China.

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