In the aircraft structure, in order to reduce their own weight, a large number of thin-walled parts made of aluminum alloy casting materials, but the thermal expansion coefficient of aluminum alloy parts is relatively large, the thermal expansion coefficient of thin-walled parts is thin. Wall aluminum parts are relatively large. The alloy is easily deformed. The deformation in the casting process of aluminum alloy, especially when free forging, requires a lot of processing work, and the deformation problem is more serious. The following is an analysis of the causes and solutions of aluminum alloy casting deformation, hoping to be helpful to everyone.

Causes of 1. machining deformation

There are many reasons for the deformation of aluminum alloy casting, which are related to the material, part shape and production conditions. There are mainly the following aspects: deformation caused by internal stress of the blank, deformation caused by cutting force and cutting heat, deformation caused by clamping force.

2. Processing Measures to Reduce Casting Deformation of Aluminum Alloy

(1) reduce the internal stress of the blank. Natural or artificial aging and vibration treatment can partially eliminate the internal stress of the blank. Pretreatment is also an effective treatment method. For the blank, due to the large margin, the deformation after processing is also large. If the excess part of the blank is pretreated to reduce the margin of each part, it can not only reduce the processing deformation of the subsequent process, but also release part of the internal stress after the internal pretreatment.

(2) Improve the cutting ability of the tool. The material and geometric parameters of the tool have an important influence on aluminum alloy casting. The correct selection of tools is very important to reduce part deformation.

Reasonable selection of tool geometry parameters. Rough angle: Choose a larger rake angle while maintaining the strength of the cutting edge. On the one hand, it can grind sharp edges, on the other hand, it can reduce cutting deformation and smooth chip removal, thereby reducing the aluminum alloy casting temperature.

Back angle: The size of the back angle directly affects the lateral wear and quality of the aluminum alloy casting surface. Cutting thickness is an important condition for selecting the relief angle. In the process of rough milling, due to the large feed speed, large cutting load and large heat generation, the tool is required to have good heat dissipation conditions. Therefore, the rear angle should be small. The cutting edge is required to be sharp during fine milling to reduce the friction between the side and the aluminum alloy casting surface and reduce the elastic deformation. Therefore, the rear angle should be larger.