The machining deformation of aluminum alloy precision parts is mainly caused by factors such as blank cutting force, cutting heat, internal stress and clamping force. Deformed products cannot be assembled. Therefore, in order to reduce processing deformation, aluminum alloy precision parts processing manufacturers can take various measures to improve the process to reduce the occurrence of deformation. Here are some effective measures:
1. Reduce the internal stress of the blank
By using natural or artificial aging and vibration treatment, the internal stress of the blank can be partially eliminated. Another method is to improve the cutting capacity of the tool, reasonably select the geometric parameters of the tool, and improve the tool structure, so as to reduce the influence of internal stress.
2. Improve the clamping method of the workpiece
For aluminum alloy thin-walled bushing parts, if the three-jaw self-centering chuck or spring chuck is used for radial clamping, once the workpiece is loosened after machining, it will inevitably be deformed. Therefore, the axial end face pressing method with good rigidity should be adopted. According to the positioning of the inner hole of the part, the threaded mandrel can be made by yourself, which is sleeved into the inner hole of the part, the end face is pressed with a cover plate, and then supported by a nut. When machining the outer circle, avoid clamping deformation, so as to obtain good machining accuracy.
For aluminum alloy thin-walled and thin-plate workpieces, it is best to choose a vacuum suction cup to obtain a uniformly distributed clamping force, and adopt a small amount of cutting to effectively prevent the workpiece from deformation.
3. Arrange the processing process reasonably
In the process of high-speed cutting, due to the large machining allowance and intermittent cutting, vibration is often generated, which affects the machining accuracy and surface roughness. Therefore, CNC high-speed cutting machining is usually divided into roughing, semi-finishing, finishing and other stages. For parts that require high precision, it is sometimes necessary to perform secondary semi-finishing and then finishing. After roughing, the parts can be cooled naturally, eliminating the internal stresses that occur during roughing, thereby reducing distortion.
In addition to the above reasons, parts made of aluminum alloy may also be deformed during machining. In practice, the method of operation is also crucial. For parts with large machining allowances, symmetrical machining should be used to ensure good heat dissipation conditions and avoid heat concentration.