In recent years, the development of industrialization has become increasingly rapid, which has put forward higher requirements for the overall processing level of the CNC machining industry, and has also put forward multiple considerations for the processing quality of aluminum parts. This has also forced CNC aluminum parts processing factories to further improve the quality of aluminum parts processing workpieces to a certain extent.
Aluminum alloy CNC machining is a mechanical processing method that uses CNC machine tools to process parts while using digital information to control the displacement of parts and tools.
1. Characteristics of CNC machining aluminum alloy
1. Low hardness of aluminum alloy
Compared with other metal materials, aluminum alloy has lower hardness, so it has good cutting performance, but at the same time, due to its low melting point and high ductility, it is very easy to melt on the finished surface or tool, and it is also easy to produce burrs and other deficiencies. Heat-treated or die-cast aluminum alloys also have higher hardness. The HRC hardness of general aluminum plates is below 40 degrees, which is not a high-hardness material. Therefore, during the CNC aluminum parts processing, the load of the processing tool will be very small. In addition, aluminum alloy has excellent thermal conductivity, and the temperature required to complete aluminum parts cutting is low, which can greatly increase the milling speed.
2. Low plasticity of aluminum alloy
"Plasticity" refers to the ability of a material to deform and continuously extend and deform under the action of external forces during processing deformation. The plasticity of aluminum alloy is mainly manifested in obtaining a high elongation and a low rebound rate. That is, it can undergo plastic deformation under the action of external forces and maintain a certain degree of deformation.
The "plasticity" of aluminum alloy is usually affected by grain size. Grain size is a key factor affecting the plasticity of aluminum alloys. Generally speaking, the finer the grain, the better the plasticity of aluminum alloys. This is because when the grain is fine, the number of dislocations generated in the material during processing will be greater, making the material easier to deform and more plastic.
Aluminum alloys have low plasticity and low melting points. When processing CNC aluminum parts, the chip removal performance is poor and the surface roughness is high. This requires the CNC processing factory to mainly solve the two problems of fixed blades and processing surface quality, which can solve the problem of aluminum alloy processing.
3. During the processing of aluminum parts, the tool is very easy to wear
During the processing of aluminum parts, due to the use of inappropriate tools, under the multiple influences of bar blades and cutting discharge problems, the wear of the tool will be more serious. Therefore, before processing aluminum parts, you should choose a tool that can control the cutting temperature to the lowest, have good front blade roughness, and can discharge the cutting smoothly. The tool with a positive rake cutting edge with wind power and sufficient chip removal space is most suitable.
2. There are several ways to process aluminum parts:
1-Hot working
This is a plastic forming process in which the aluminum alloy ingot is fed above the recrystallization temperature. During hot working, the plasticity of the ingot is high and the deformation resistance is low, and equipment with smaller capacity can be used to produce products with larger deformation.
2. Cold working
Cold working refers to the plastic forming process completed below the temperature where recovery and recrystallization do not occur. The essence of cold working is a combination of cold working and intermediate annealing. Cold working can produce a final product with a smooth surface, precise size, good organizational properties and meeting different performance requirements.
3-Warm working
Warm working is a plastic forming process between cold working and hot working. The main purpose of warm working is to reduce the deformation resistance of metals and improve the plastic properties of metals.
3. The following matters should be noted when processing aluminum alloys:
1- Setting and controlling the temperature of aluminum profiles. Generally speaking, there is a certain error between the temperature and the displayed temperature. When setting the surface temperature, it should be set according to the actual temperature of the equipment, and pay close attention to the temperature fluctuation
2- Aluminum profile aging and insulation. The aging should be set strictly in accordance with the processing technology requirements, and the insulation time should also be appropriate to prevent insufficient hardness due to insufficient aging or too long aging.
3- The extrusion frame of aluminum profiles should not be too dense, and there should be gaps between materials. The gaps between aluminum profiles, especially small and thick materials without ventilation, need to be larger. When pipes, small materials and sheets are combined in one frame, the pipes are placed below to facilitate aging circulation and air supply.
"Aging" in the process of CNC aluminum parts processing refers to the heat treatment of aluminum alloys to achieve higher strength and hardness. After aluminum alloy parts undergo many processes such as die casting, processing, and annealing, the mechanical properties and tensile strength of the materials will be insufficient due to their uneven grain size and distribution. The "aging" treatment is to heat the material to a specific temperature again and keep it for a certain time after these processes, so that the grains in the material can be rearranged and form a uniform structure, thereby improving the hardness and strength of the material.
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