With the rapid development of material science and manufacturing technology, aluminum alloy parts, especially aluminum alloy housing parts, are more and more widely used in industrial fields and daily life. With the expansion of the application range and the increase in the number of applications, the requirements for the machining quality of aluminum alloy shells are also getting higher and higher. For this reason, the machining technology and cnc machining quality of aluminum alloy shells have attracted more and more attention. PTJ Precision, which has long been engaged in aluminum alloy casings, has explored and summarized effective methods to reduce deformation during the machining of aluminum alloy casings in actual production.
For workpieces with poor rigidity of aluminum alloy shell, the deformation can be reduced by improving the fixture and stuffing.
For thin-walled aluminum alloy shell workpieces, three-jaw self-centering chucks or spring chucks cannot be clamped from the radial direction, because the workpiece will be deformed once it is released after machining. Therefore, the method of pressing the axial end face with better rigidity should be fully utilized to reduce the deformation of the workpiece. Use the inner hole of the part to locate it. It is recommended to make a threaded mandrel, insert it into the inner hole of the part, and then use a cover plate to press the end face tightly with a nut. Clamping deformation can be avoided when machining the outer circle, so as to obtain satisfactory machining accuracy.
When machining aluminum alloy shell workpieces, it is recommended to use vacuum suction cups to obtain evenly distributed clamping force. During machining, use a small amount of cutting to effectively prevent workpiece deformation.
According to PTJ Precision’s machining practice, the packing method can also be used for aluminum alloy shell machining. In order to increase the process rigidity of the shell workpiece, a medium can be filled inside the workpiece to reduce the large deformation of the workpiece during clamping and cutting. For example, pour the urea melt containing 3%-6% potassium nitrate into the workpiece, and after finishing the machining, immerse the workpiece in water or alcohol to dissolve the filling and pour it out.
If there are multiple cavities on the aluminum alloy shell parts, it is not advisable to process one cavity by cavity one by one, because it is easy to cause uneven stress and deformation of the parts. Multi-layer machining is adopted, and each layer is processed to all cavities at the same time as much as possible, and then the next layer is processed to make the parts receive uniform force, thereby achieving the purpose of reducing deformation.
The aluminum alloy shell workpiece is often deformed due to clamping during machining. In order to minimize the deformation of the workpiece, you can loosen the compression piece before the finishing process reaches the final size to restore the workpiece to its original state. Then perform a slight compression, whichever is just able to clamp the workpiece (completely based on personal experience) to ensure the ideal machining effect. PTJ’s precise machining experience proves that the best point of clamping force is on the supporting surface, and the clamping force should act in the direction of good rigidity of the workpiece. Under the premise of ensuring that the workpiece does not loosen, the smaller the clamping force, the better.
In addition, when machining aluminum alloy shell workpieces, try not to let the milling cutter plunge directly into the part like a drill bit when machining the cavity, resulting in insufficient chip holding space of the milling cutter and unsmooth chip evacuation, resulting in overheating, expansion and Phenomena such as broken knife and broken knife. Therefore, PTJ Precision recommends to first drill the hole with a drill of the same size as the milling cutter or one size larger, and then mill with the milling cutter, or use CAM software to produce the spiral cutting program to reduce the deformation of the aluminum box shell workpiece and ensure the workpiece quality.
PTJ Precision believes that today, as the application range of aluminum alloy shells is expanding, as an aluminum alloy shell machining enterprise, it is necessary to improve the technical level of operators, and summarize different cnc machining techniques for aluminum alloy shell machining according to the different uses and working environment of different workpieces. And the method effectively improves the machining quality of the aluminum alloy shell.