PCD tool cutting aluminum alloy material
Problems we often encounter when processing aluminum alloy materials:
1. Low efficiency of processing
2. Poor surface quality
3. Short tool life
4. Processing stability is not high
At present, our common aluminum alloys are medium-silicon aluminum alloys and high-silicon aluminum alloys.
The characteristics of medium silicon aluminum alloy and high silicon aluminum alloy are:
▶ Contains brittle particles of hard silicon, which will produce a lot of abrasive wear during cutting
▶ Wear increases with silicon content
▶ Low hardness and low melting point A lot of cutting heat is generated during processing, which is easy to scratch the surface and reduce the surface quality.
▶ The thermal expansion coefficient is large, the elastic modulus is small, and the parts will expand and contract during processing, which makes it difficult to control the precision of the processing size.
▶ With the popularity of automation, the requirements for tool life and stability are more stringent.
How to solve the problem when processing aluminum alloy?
Using suitable superhard tools, we can easily solve the cutting problem of aluminum alloys.
First of all, we can understand what superhard tool materials are:
Single crystal diamond: There is no grain boundary inside, and the cutting edge of the tool can theoretically process the straightness and sharpness of the atomic scale. The theoretical value of surface roughness during machining approaches zero. And then to achieve mirror processing, is an ideal precision machining tool. However, the toughness is relatively poor, and it is currently more suitable for ultra-precision machining.
CVD coated diamond tool: high hardness, high thermal conductivity. It is suitable for processing non-metallic materials such as solid wood and carbon fiber composite materials. It has excellent performance, and the coating adhesion is weak. Higher cutting forces can cause the coating to peel off and reduce tool life. It is suitable for processing non-metallic materials that do not stick to the knife and have low cutting force.
Polycrystalline diamond (PCD) tools: Although the hardness and wear resistance are lower than that of single crystal diamond and CVD diamond, their unique toughness and impact resistance are better. Overall its general performance is better, suitable for both finishing and semi-finishing. Therefore, PCD Cutting tools are more widely used at present, and the amount is also the largest.
After understanding superhard tool materials, we can find that using PCD Cutting tools to cut aluminum alloys is the best choice.
The performance characteristics of PCD tool materials are as follows
● Has high hardness and wear resistance
Vickers hardness HV7000~8000 is 8~12 times that of cemented carbide.
● Low friction coefficient
0.1~0.3, the cutting force can be obviously reduced during cutting.
● High thermal conductivity
700w/m*k, which is 1.5~9 times that of cemented carbide. The heat transfer rate is fast during cutting, which can better maintain the cutting edge material.
● High elastic modulus
800~900gpa, high rigidity, not easy to bend and deform, to ensure processing accuracy.
● Low thermal expansion coefficient
It is one-fifth of cemented carbide, with small thermal deformation and high machining accuracy.
● Chemical affinity is not strong
The affinity with non-ferrous metals or non-metal materials is small, and it is not easy to react during processing.
Superhard cutting tools are widely used in general machinery, aerospace, automobile manufacturing, electronic information, medical equipment, defense and military industries, etc., which greatly promotes the development of cutting processing and advanced manufacturing technology. It has become an indispensable and important means in modern machining.
Depending on the diamond particle size and content, the workpieces suitable for processing are also different.
The average particle size of ultra-fine-grained PCD diamond tools is between 0.5 and 1, and the diamond volume content is about 91%. Suitable for finishing machining.
The average particle size of fine-grained PCD diamond tools is around 6, and the diamond volume content is about 92%. Suitable for processing copper, solid wood and other wood-based materials.
The average particle size of PCD diamond tools with medium particle size is about 10, and the diamond volume content is about 93%. Suitable for semi-finishing and finishing. Ideal for use as turning inserts.
The average particle size of PCD diamond tools with coarse and fine mixed crystals is between 2 and 30, and the diamond volume content is about 95%. It is suitable for processing high-silicon aluminum alloys (silicon content greater than 12% belongs to high-silicon aluminum alloys), and is suitable for processing carbon fiber composite materials, tungsten and other brittle materials.
Case study
Case of reaming of intake hole of cylinder head solenoid valve
Silicon content between 8~15% Ra0.61
Oil pump housing boring case
Silicon content 8~10%
