Why does aluminum alloy precision parts deform?
The machining deformation of aluminum alloy precision parts is mainly caused by such factors as blank cutting force, deformation caused by cutting heat, deformation caused by internal stress, and deformation caused by clamping force. We cannot allow deformed products to complete final assembly. Therefore, in order to reduce machining deformation, manufacturers of aluminum alloy precision parts can take various measures to improve the process to reduce deformation. The first technique is to reduce the internal stress of the blank.
Aluminum alloy precision parts
First: reduce the internal stress of the blank.
Reduce the internal stress of the blank. Natural or artificial aging and vibration treatment can partially eliminate the internal stress of the blank; Or improve the cutting ability of the tool. The geometric parameters of the tool are selected reasonably, and the tool structure is improved. The second skill is to improve the clamping method of the workpiece.
Secondly, improve the clamping method of the workpiece.
For aluminum alloy thin-walled bushing parts, if a three jaw self centering chuck or spring chuck is used for radial clamping, the workpiece will inevitably deform once loosened after processing. At this time, the axial end face pressing method with good rigidity shall be adopted. According to the positioning of the inner hole of the part, the thread spindle is self-made and the inner hole of the part is sleeved. Press the end face with a cover plate, and then support it with a nut. When machining the excircle, the clamping deformation can be avoided, thus obtaining satisfactory machining accuracy.
When machining aluminum alloy thin-wall and thin sheet workpieces, it is better to select vacuum suction cups to obtain uniformly distributed clamping force, and then use small cutting amount for processing, which can well prevent workpiece deformation.
Third: Reasonably arrange the process In the high-speed cutting process, because of the large machining allowance and intermittent cutting, vibration often occurs in the milling process, which affects the machining accuracy and surface roughness. Therefore, NC high-speed cutting can generally be divided into rough machining - semi finishing - cleaning - finishing. For parts with high accuracy requirements, it is sometimes necessary to conduct secondary semi finishing and then finish machining. After rough machining, the parts can be naturally cooled to eliminate the internal stress generated by rough machining and reduce deformation.
In addition to the above reasons, aluminum alloy parts will also deform during processing. In practice, the operation method is also very important. For parts with large machining allowance, symmetrical machining shall be adopted during machining in order to provide better heat dissipation conditions and avoid heat concentration.