ABSTRACT: With the development of Science and technology and the innovation of China's metal industry, aluminum alloy is widely used in industrial production because of its high density, high strength, good plasticity and resistance to electric conduction and heat corrosion. This paper analyzes the mechanical processing technology of Aluminum Alloy material, improves the quality of aluminum alloy material, makes extensive use of aluminum products in all walks of life, and guarantees the overall economic benefit. Key words: Aluminum Alloy Material; Mechanical Processing Technology; process analysis in recent years, China's mechanical processing production summary has continuously increased the processing volume of aluminum alloy parts, aluminum alloy parts have also become more complex, for the parts size and roughness and other aspects put forward higher requirements. In the aluminum alloy processing process, the deformation problem will affect the aluminum alloy material processing progress and Surface roughness. In order to improve the qualification rate of aluminum alloy parts, it is necessary to optimize the mechanical processing technology of aluminum alloy materials, make clear the processing characteristics of aluminum alloy materials, improve the precision of aluminum alloy parts, and promote the sustainable development of aluminum alloy processing industry in China.

1. The influence factors of aluminum alloy processing technology

 1.1 properties of aluminum alloy materials are summarized

At present, aluminum alloy materials are widely used in various fields of industry, and the whole application range is very wide. Because the properties of aluminum alloy materials and other metals are quite different, the welding properties of aluminum alloy materials need to be improved, after the welding is completed, different types of weld defects are left in the weld, such as serious blowhole and crack problems. In the process of using aluminum alloy material, it has higher shrinkage, in the welding work, because aluminum alloy material is easy to produce crack, will cause the welding deformation problem. Therefore, in practice, the staff need to take targeted measures to control welding defects, efficient use of aluminum alloy materials. Because the aluminum alloy material has good plasticity, high strength and low density, in the process of using the aluminum alloy material, it is necessary to take the new way according to the material performance, so that the utilization rate of the aluminum alloy material is constantly improved.

1.2 residual stress in machining

(1) the comprehensive effect of stress: In the process of machining parts, cutting will change the stress balance, resulting in the internal organization of the state affected. In the process of machining aluminum alloy, it is necessary to use the cutting tool to cut. The aluminum alloy material will deform along the cutting direction, at the same time, it will pull the neighboring layers, and create the residual tensile stress on the surface of the aluminum alloy material, in the inner layer, the production capacity takes part in the compressive stress. Under the influence of the comprehensive action, the aluminum alloy parts deform. 

(2) residual tensile stress: In cutting work, the plastic deformation problem is caused by the friction resistance, which generates more heat on the surface of the aluminum alloy and causes the material to expand. If the inner layer temperature is lower, the surface layer will expand, it blocks the inner material, causing thermal stress in the surface metal. If the thermal stress exceeds the yield limit of aluminum alloy, the compressive plastic deformation will occur. After finishing the cutting work, the surface temperature of the aluminum alloy parts will be lowered continuously, which will lead to the decreasing of the volume and the tensile stress on the surface.

(3) analysis of cutting heat in cutting: under the action of cutting tools, the metal being cut will produce elasticity and plastic deformation, which is the main source of cutting heat. The friction between the chip and the rake face consumes work, as does the friction between the workpiece and the rake face, thus producing heat. The main influencing factors of cutting temperature include: 1 cutting parameters: cutting speed will affect the cutting temperature, constantly increasing the cutting speed, also will improve the quality of cutting temperature. Eating knife changes, will also change the heat dissipation area and generate heat, so eating knife will affect the cutting temperature. 2 Tool Geometry Angle: Increasing Rake Angle will reduce the cutting temperature. Because increasing the Rake Angle, will reduce the unit cutting force, thus reducing the cutting heat. Rake in the 25 to 30 grit, not affecting the cutting temperature, because reduced wedge angle, thus reducing the heat dissipation volume. Reduce the main deflection angle, will therefore increase the cutting width, reduce the cutting, will reduce the cutting temperature. The radius of the tool tip is in the range of 0 ~ 0.5 mm, which will not affect the cutting temperature. When the radius of arc is increased, the plastic deformation will be increased, and the heat dissipation of the cutting tool will be improved, and the balance of the two will be kept, so as to avoid affecting the cutting temperature. 3 tool wear: if the tool wear reaches a certain value, it will affect the cutting temperature and increase the cutting speed.

2. Machining process of aluminum alloy material 2.1 rough machining of aluminum alloy material

In the process of aluminum alloy material processing, workers need to choose the processing datum reasonably, ensure the processing datum accord with the design datum, and improve the stability and reliability of aluminum alloy material in the actual work. Because it is difficult to precisely control the dimensional progress and roughness of aluminum alloy parts, in the process of machining, workers need to process complex materials. In the rough machining stage, it is necessary to select a reasonable method to ensure the performance of aluminum alloy materials, not only to use aluminum alloy materials efficiently, but also to ensure the accuracy of machining dimensions. In view of the special shape, the staff can use the control machine tool rough processing material, uses the coolant cooling processing workpiece, guarantees the processing progress. In the rough processing stage, it is necessary to increase the amount of knife to eat, and at the same time, it is necessary to reduce the amount of feed to improve the heat transfer.

2.2 in the process of finishing and processing aluminum alloy materials, workers should select suitable equipment to finish and process aluminum alloy materials to meet the size standard in the process of finishing and processing aluminum alloy materials, and meet the demands of the Surface roughness. In the aluminum alloy material finishing stage, if the aluminum alloy material has been roughed, can reduce the finishing workload, select high-precision workpiece, so that the precision of aluminum alloy parts. In the process of processing aluminum alloy materials, there will be more cutting heat, because aluminum alloy materials have lower melting point, aluminum alloy materials are easy to deformation at high temperature, workers need to use cutting also finish processing aluminum alloy materials, reduce the processing temperature, avoid the deformation of aluminum alloy parts, but also will not produce cutting error.

2.3 Heat treatment and cold treatment are used in the processing of aluminum alloy materials. The methods of artificial aging and recrystallization annealing are needed. If the part structure is relatively simple, first rough machining, then the use of heat treatment, the final implementation of finishing. If the part structure is more complex, first implement rough machining, then implement semi-finishing after heat treatment, then use heat treatment, finally implement finishing. In the process of aluminum alloy material processing, it is necessary to analyze the properties of aluminum alloy materials, and to make use of the targeted processing technology to avoid mistakes in the process. Workers can use artificial aging recrystallization annealing method. A number of aluminum alloy materials with a high processing schedule, after finishing the implementation of heat treatment, to avoid future use of parts in the process of problems. The cold treatment, mainly low temperature treatment, is used to improve the structure of aluminum alloy body and improve the stability of the structure size. In the actual processing work, cold treatment and heat treatment can be combined with recrystallization annealing, using high and low temperature impact effect, improve the accuracy of aluminum alloy material size.

2.4 the melting point of aluminum alloy is relatively low, so the aluminum alloy has high thermal conductivity and can conduct more heat in the process of cutting. In the cutting stage, aluminum alloy parts will quickly increase its temperature, so the staff need to choose a reasonable tool, the appropriate increase to the tool Surface roughness, thus reducing the cutting force. Alumina-based ceramic tools can not be used in the processing of aluminum alloy materials, because the use of such tools, aluminum alloy materials will produce alumina due to oxidation, and tool materials. Therefore, the problem of mutual attraction is generated, which increases the friction in the cutting process and tool wear. In short, in the process of processing aluminum alloy materials, the staff should reasonably choose cutting tools, precision processing aluminum alloy materials.

3. Safety Technology for Aluminum Alloy material processing 3.1 rolling processing technology rolling processing technology is a rough processing technology, suitable for the production of large quantities of aluminum alloy materials in the process of application, but also suitable for the use of simple profiles, because this profile for Aluminum Alloy surface smoothness requirements are relatively low. The rolling technology mainly uses the friction force of the rotating roller and the aluminum alloy, feeds the aluminum alloy material to the roller, uses the high pressure function of the roller, compresses the deformed aluminum alloy material, guarantees the aluminum alloy material to meet the market demand. 3.2 extrusion processing technology extrusion processing technology belongs to finish processing technology, at present the production enterprise mainly uses the aluminum alloy to shape the method. According to the operating mechanism, extrusion technology is divided into forward extrusion, backward extrusion and forward-backward combined extrusion. In the process of extrusion, aluminum alloy ingots are put into the extrusion barrel, after the constant temperature of the heating machine is reached, aluminum alloy can flow out from the side die hole by using the circumspect extrusion pressure, and the aluminum alloy ingots can be plastic treated, so the aluminum alloy products are formed. Because the variety and the specification and so on aspect difference, causes the aluminum alloy material manufacture detail also to have the certain difference. 3.3 forging technology aluminum alloy forging technology has advanced, mainly divided into free forging and membrane forging and model forging. At present, forging technology is widely used in aluminum alloy manufacturing enterprises in China, which makes use of static pressure and auxiliary impact force to cause molecular flow of aluminum alloy materials, so the aluminum alloy products are obtained to meet the requirements of size and shape. 

4. Conclusion in the process of mechanization, the machining quantity of parts is increased, and the requirement of dimension precision and roughness is improved. In the process of machining aluminum alloy materials, the workers need to integrate all factors to ensure that aluminum alloy products meet the working standards, and to promote the use of aluminum alloy materials in more fields in China to ensure the overall economic benefits. 

Source: Chinanews.com, by Liu Wenping

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