Aluminum alloy is an important industrial raw material. Due to its relatively small hardness and large thermal shrinkage coefficient, it is easy to deform in the machining of thin-walled and thin-plate parts. In addition to improving the performance of the tool and using aging treatment to eliminate the internal stress of the material in advance, from the perspective of processing technology, some measures can also be taken to reduce the processing deformation of the material as much as possible.
For aluminum alloy parts with large machining allowance, in order to create better heat dissipation conditions and reduce thermal deformation, it is necessary to avoid excessive heat concentration as much as possible. The method that can be taken is symmetrical machining. For example, there is an aluminum alloy plate with a thickness of 90 mm, which needs to be milled to a thickness of 60 mm. If one side is milled and the other side is immediately turned over to mill the other side, since each side is processed at one time, it is processed continuously. If the margin is large, the problem of heat concentration will be formed.
The flatness of the milled aluminum alloy plate can only reach 5 mm. If the symmetrical processing method of repeated feeding on both sides is adopted, each side is processed at least twice until the final size is reached, which is conducive to heat dissipation, and the flatness can be controlled at 0.3 mm.
Layered and repeated processing method When there are multiple cavities on the aluminum alloy plate parts that need to be processed, if one cavity and one cavity are processed sequentially, it is easy to cause the cavity wall to be deformed due to uneven stress. A good solution is to adopt the multi-layered processing method, that is, to process all the cavities at the same time, but not to complete the processing at one time, but to divide into several levels and process them to the required size layer by layer. In this way, the force of the parts will be relatively average, and the probability of deformation is small.
Choosing the right cutting amount Selecting the appropriate cutting amount can effectively reduce the cutting force and cutting heat during the cutting process. In the machining process, the excessive cutting amount will lead to excessive cutting force in one pass, which is easy to cause deformation of the parts, and will affect the rigidity of the machine tool spindle and the durability of the tool. Among the various elements of the cutting amount, the one that has the greatest influence on the cutting force is the amount of back engagement.
It is said that reducing the amount of back cutting is beneficial to ensure that the parts are not deformed, but at the same time, it will reduce the processing efficiency. The high-speed milling of CNC machining can solve this problem. It only needs to reduce the amount of back cutting, correspondingly the feed rate, and increase the speed of the machine tool, which can not only reduce the cutting force, but also ensure the processing efficiency.
