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Precautions for CNC machining of aluminum alloy

01 Basic characteristics of aluminum

The specific gravity of aluminum is about 2.7, much lighter than iron and copper. It also has high thermal and electrical conductivity, as well as excellent corrosion resistance. In addition, the high ductility and toughness of aluminum, as well as its tendency to undergo plastic deformation, enable it to be processed using various methods.

The following characteristics have a significant impact on the machining process.

Lightweight and soft texture, low cutting resistance

Chips are easily discharged in long strips, which can lead to entanglement

High thermal conductivity can suppress tool wear, but it is prone to chip accumulation (welding) phenomenon

An oxide film will form on the surface, although it has high corrosion resistance, sometimes it can also affect the state of the machined surface

02 Advantages of Aluminum Cutting

The biggest advantage of cutting aluminum is its extremely high machinability. Compared to iron or stainless steel, aluminum exerts less pressure on cutting tools, resulting in faster cutting speeds.

The specific benefits are as follows:

1. High production efficiency: It can achieve high-speed cutting, thereby shortening processing time.

2. Long tool life: Due to high thermal conductivity, the heat generated at the cutting point is easily diffused.

3. Excellent surface roughness (high smoothness): Under appropriate processing conditions, a smooth surface close to a mirror can be obtained.

4. Easy to process complex shapes: Its lightweight and flexible characteristics make it suitable for micro machining and thin-walled machining.

Therefore, aluminum is often used for various processing applications, from prototype production to mass production of products.

Running Industry has over 30years Al alloy precision cnc machining experience, will assist our customer to get their Al products under the requirements.

03 Difficulty in Aluminum Processing

The processing of aluminum also faces its own unique challenges. Understanding its advantages and disadvantages is crucial.

Difficulty in chip breaking and removal: Due to the high ductility of the material, the chips are in the form of long strips, making it easy for them to wrap around the tool or workpiece.

Tool chip buildup (welding): Aluminum has a low melting point and is prone to adhering to the tool tip, forming chip buildup, which can lead to burrs or rough machining surfaces.

Ensure dimensional accuracy: Due to the soft texture of the workpiece, slight deformation may occur during the cutting process, resulting in dimensional errors.

Surface smoothness variation: Under inappropriate conditions, the processed surface may become cloudy or rough.

To overcome these difficulties, it is necessary to develop measures such as tool selection, cutting conditions, and cooling methods.

04 Key points for selecting tools

In aluminum processing, the selection of cutting tools has a significant impact on both processing quality and efficiency. The key points to consider are as follows:

1. Materials: Hard alloy cutting tools and diamond coated cutting tools have good performance. Cutting tools designed specifically for aluminum processing have sharp edges.

2. Blade angle: A larger rake angle can improve cutting performance and achieve smoother chip removal.

3. Surface treatment: Common universal coatings such as TiN (titanium nitride) have a high affinity for aluminum, and it is recommended to use DLC (diamond-like carbon) coatings or uncoated cutting tools.

Using appropriate tools for proper machining can significantly improve machining accuracy and tool life.

05 Improve cutting conditions

Compared to iron and stainless steel, aluminum can be cut at a higher speed. By optimizing cutting conditions, machining quality can be improved and tool life can be extended.

01 Cutting speed: It can rotate at high speed (sometimes exceeding 1000 meters per minute).

02 Feed rate: If the feed rate is too small, the chips will become extremely thin, which can easily lead to tool sticking (dissolution). Therefore, a reasonable feed rate must be set.

03 Cutting depth: Adjust according to the stiffness of the workpiece. Special attention should be paid to thin-walled parts.

04 Cooling method: Using cutting fluid (cooling oil) or air blowing to assist in chip removal can help prevent tool sticking and take away heat.

By appropriately combining these elements, efficient processing utilizing aluminum processing characteristics can be achieved.

06 Precautions for each type of aluminum alloy

Aluminum exists in various forms, including pure aluminum and various alloys. Its machinability and surface treatment performance depend on the type of alloying element.

01 Pure Aluminum (1000 Series): Soft texture, easy to process, but the surface after processing is prone to become sticky and dull.

02 Aluminum Copper Alloy (2000 Series): High strength, but also high cutting resistance, leading to rapid tool wear.

03 Aluminum Magnesium Alloy (5000 Series): It has excellent corrosion resistance, but has a noticeable tendency to stick to the cutting edge during processing.

04 Aluminum Zinc Alloy (7000 Series): High strength, good processing performance, but due to its high hardness, attention must be paid to avoiding tool wear.