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How to solve the deformation of five-axis machining aluminum alloy parts?
CNC machine tools used in the five-axis machining of aluminum alloys are usually called five-axis CNC machine tools, or five-axis machining centers. Mainly used for five-axis machining of aviation parts, medical equipment parts, machining parts with free-form surfaces, five-axis machining of impellers, etc.
Five-axis machining center machine tool can process different sides of the workpiece without changing the position of the workpiece on the machine, which can greatly improve processing efficiency. The five-axis machining center can realize multi-faceted processing such as milling, drilling, and tapping in one clamping, and can also process free-form surfaces of complex parts through five-axis linkage.
Parts of aluminum parts are deformed during the five-axis machining process, and the causes and conditions are different. In actual operation, in order to reduce the deformation of aluminum alloy materials, the processing and deformation operation methods are also very important. There are mainly the following 6 types:
- Five-axis simultaneous machining For parts with large machining allowances, in order to make them have better heat dissipation conditions during the machining process and avoid heat concentration, symmetrical machining should be used during machining. If a 90mm thick sheet needs to be processed to 60mm if one side is milled and the other side is milled immediately, and the final size is processed at one time, the flatness will reach 5mm; if it is symmetrically processed by repeated feeding, each side is processed twice to The final dimension can guarantee a flatness of 0.3mm.
- If there are multiple cavities on the plate parts, it is not suitable to use the sequential processing method of one cavity and one cavity during processing, which will easily cause uneven stress on the parts and cause deformation. Multi-layer processing is adopted, and each layer is processed to all the cavities at the same time, and then the next layer is processed to make the parts evenly stressed and reduce deformation.
- Five-axis CNC machining reduces cutting force and cutting heat by changing the cutting amount. Among the three elements of cutting amount, the amount of back-engagement has a great influence on the cutting force. If the machining allowance is too large, the cutting force of one pass is too large, which will not only deform the parts but also affect the rigidity of the machine tool spindle and reduce the durability of the tool.
If the number of knives to be eaten by the back is reduced, the production efficiency will be greatly reduced. However, high-speed milling is used in CNC machining, which can overcome this problem. While reducing the amount of back-cutting, as long as the feed is increased accordingly and the speed of the machine tool is increased, the cutting force can be reduced and the processing efficiency can be ensured at the same time.
- The order of the five-axis machining of aluminum alloys should also be paid attention to. Rough machining emphasizes improving machining efficiency and pursuing the removal rate per unit of time. Generally, up-cut milling can be used. That is, the excess material on the surface of the blank is removed at the fastest speed and the shortest time, and the geometric contour required for finishing is basically formed. While finishing emphasizes high precision and high quality, it is advisable to use down milling. Because the cutting thickness of the cutter teeth gradually decreases from the maximum to zero during down milling, the degree of work hardening is greatly reduced, and the degree of deformation of the part is also reduced.
- Thin-walled workpieces of aluminum alloy medical equipment parts are deformed due to clamping during processing, and even finishing is unavoidable. In order to reduce the deformation of the workpiece to a minimum, just before the finishing is about to reach the final size, loosen the pressing piece to make the workpiece free to return to its original state, and then press it slightly, as long as the workpiece can just be clamped (completely). According to the hand feel), the ideal processing effect can be obtained. In a word, the action point of the clamping force is preferably on the supporting surface, and the clamping force should be applied in the direction of good rigidity of the workpiece. On the premise of ensuring that the workpiece is not loose, the smaller the clamping force, the better.
- Aluminum alloy five-axis machining When machining parts with a cavity, try not to let the milling cutter plunge directly into the part like a drill when machining the cavity, resulting in insufficient space for the milling cutter to accommodate chips and unsmooth chip removal, resulting in parts Unfavorable phenomena such as overheating, expansion, and knife breakage. First, drill the hole with a drill of the same size.as the milling cutter or one size larger, and then mill it with the milling cutter. Alternatively, you can use the CAM five-axis CNC software to set the helical cutting program.
The main factor affecting the machining accuracy and surface quality of aluminum parts are that such parts are prone to deformation during the machining process, which requires the operator to have certain operating experience and skills. As a factory with more than ten years of experience, if you have the same problem You can always contact us to help you solve it.