Due to the fact of Aluminum is easy to be machined, with light-weight and high strength, but low cost, aluminum is one of the best metal material for cnc machining, nowadays aluminum alloy become the most widely used metal material in industry and the best good popular material for cnc machining custom parts, it has been widely used in aviation, aerospace, automobile, machinery manufacturing, shipbuilding and chemical industries. In order to reduce the weight of the aircraft structure, a large number of thin-walled parts made of aluminum alloy materials are used. Due to the large thermal expansion coefficient of the aluminum alloy parts, the thin-walled parts are easily deformed during the thin-wall processing, let’s find out solutions to solve the problem of deformation in aluminum alloy machining:
6 WAYS to solve the problem of deformation in aluminum alloy machining
1.Reduce the internal stress of the aluminum raw material
Pre-processing is an effective method to reduce deformation. When the machining allowance of aluminum alloy raw materials is large, the deformation after machining is also large. If the excess part of the raw material is processed in advance to reduce the processing allowance of each part, not only can the processing deformation of the subsequent processing procedures be reduced, but also a part of the internal stress can be released after the pre-processing is placed for a period of time.
2.Improve the cutting ability of the tool
The material and geometric parameters of the tool have an important influence on the cutting force and cutting heat. Choosing the right and appropriate tool is very important to reduce the deformation of the parts.
3.the choice of tool geometric parameters
- Rake angle: Under the condition of maintaining the strength of the cutting edge, the rake angle should be appropriately selected to be larger. On the one hand, it can grind a sharp edge, and on the other hand, it can reduce cutting deformation and smooth chip removal, thereby reducing cutting force and cutting temperature. Never use negative rake angle tools.
- Relief angle: The size of the relief angle has a direct effect on the wear of the flank surface and the quality of the machined surface. Cutting thickness is an important condition for selecting the relief angle. During rough milling, due to the large feed rate, heavy cutting load, and large heat generation, good heat dissipation conditions of the tool are required. Therefore, the clearance angle should be selected smaller. When finishing milling, the cutting edge is required to be sharp, to reduce the friction between the flank face and the machined surface, and to reduce the elastic deformation. Therefore, the relief angle should be selected larger.
- Helix angle: In order to make the milling smooth and reduce the milling force, the helix angle should be selected as large as possible.
- Entering angle: Appropriately reducing the entering angle can improve the heat dissipation conditions and reduce the average temperature of the processing area
4.Improve the tool structure
- Reduce the number of teeth of the milling cutter and increase the chip space. As aluminum alloy material has greater elasticity, larger cutting deformation during machining, and larger chip holding space, the bottom radius of the chip pocket should be larger and the number of teeth of the milling cutter should be smaller.
- Before using a new knife, you should lightly sharpen it with a fine oil stone on the front and back of the knife teeth to eliminate the remaining burrs and slight serrations when sharpening the knife teeth. This not only reduces the cutting heat but also reduces the cutting deformation.
- After the tool wears, the surface roughness value of the workpiece increases, and the deformation of the workpiece increases with the increase of the cutting temperature. Therefore, the tool material with good wear resistance should be selected.
5.Improve the clamping method of the workpiece
- .Thin-walled aluminum alloy workpieces can use the following clamping methods to reduce deformation.
- .Thin-walled bushing parts should use the method of pressing the axial end face with better rigidity to avoid clamping deformation when processing the outer circle and obtain satisfactory processing accuracy.
- .When processing thin-walled and thin-plate workpieces, it is best to choose a vacuum chuck to obtain a uniform clamping force, and then process it with a smaller cutting amount, which can well prevent the deformation of the workpiece.
6.Use special aluminum alloy cutting oil
Special cutting oil is a kind of medium that must be used in CNC cutting process, which mainly plays the role of lubrication, cooling, cleaning, etc. during the machining process. Due to the continuous improvement of high-speed cutting tools, equipment and processes, new cutting oils usually use sulfurized extreme pressure anti-wear additives as their core components, which can effectively protect the tools in the ultra-high-speed cutting process, improve process accuracy and cutting efficiency, and prevent workpieces. The emergence of deformation problems.
