2. Process analysis
Since the mobile phone model is composed of an upper and lower surface and four sides, how to efficiently and accurately process the six surfaces to be processed is the first problem to be solved in mobile phone processing. Based on the above situation, there are currently two sets of feasibility. Program:
Option 1: The material is selected from a square piece of 25mm × 50mm × 120mm, and the center of the mobile phone model is at the center of the material. The upper and lower parts are machined, the upper surface is machined first, and then the upper half of the four sides are machined; then the workpiece is removed, and the bottom is then clamped, and the bottom surface and the lower half of the four sides are machined. It can be processed in general CNC machine tools. Although this solution is feasible, there are many problems encountered in the actual machining process, for example, when the upper surface of the mouse and the upper half of the four sides are machined, then the bottom surface and the lower half of the four sides are turned over. In this way, the four side faces of the secondary clamping are prone to joint marks, so that the two faces processed cannot be smoothly transitioned.
Solution 2: In order to overcome the shortcomings of the first scheme and make the four sides smooth transition, it is necessary to make the mobile phone model form once, once clamped, and finish all the faces to avoid secondary clamping, so I choose Φ50mm bar material, The bar is clamped on the A-axis by a three-jaw chuck using a clamp-top method. Each surface is machined, rotated 90°, and the other surface is machined, and the four faces are processed in turn. The machining method using this rotary side processing during processing, once formed, overcomes the difficulties encountered in the first scheme, and the processing efficiency and accuracy are improved compared with the first scheme.
Therefore, the second option is chosen as the best solution.
(1) Selection of clamping method The cylindrical bar material should be processed on the four-axis CNC machine tool, and the three-jaw chuck is clamped, and the method of one clip and one top is adopted, as shown in Fig. 12.
Figure 12 Positioning clamping
(2) Formulation of the processing technology The main part of the part has high requirements on the surface quality after processing. Therefore, the entire body part of the mobile phone is processed by using the clamping as much as possible. The overall idea of ​​mobile phone processing: rough processing → finishing, the specific analysis is as follows:
Roughing methods: face milling (2D) and parallel machining. The plane machining is mainly to mill out the excess material of the blank. This method is two-dimensional milling. The tool path is simple and easy to control, and the machining efficiency is high. Therefore, this method is selected, and the simulation effect diagram is shown in Fig. 13. Parallel machining mainly removes a large amount of cutting allowance on the surface of the mobile phone. The machining method generates simple cutting paths, is parallel to each other, is relatively simple and is not easy to make mistakes, and can be cut in both directions, so that the machining efficiency can be greatly improved, as shown in FIG. . When roughing the surface, since the surface of the mobile phone model is mostly curved, the ball-end milling cutter is used, and a finishing allowance of 0.5 mm is left.
Figure 13
Figure 14
Finishing methods: Parallel, Scallop, Contour, Flowline, and Leftover.
Parallel machining: It mainly removes a large amount of cutting allowance on the surface of the mobile phone. The machining method generates a simple cutting path and can be cut in both directions, which can greatly improve the processing efficiency.
Contour shape processing: The fillet of the mobile phone is machined to the size, the generated tool path can be adjusted very densely, very smooth, and the rounded effect is better.
Cross-cut clearing: Since there are many small corners where large-diameter tools cannot be milled, small-diameter tools must be used for milling. With this method, only these places are processed.
Residual material clearing angle processing: mainly after the intersection of the clearing angle, there will be a small amount of residual margin, not removed, it can be removed by this processing method.
Surface streamline processing: mainly processing the surface around the screen of the mobile phone, the generated tool path can be adjusted very dense, very smooth, and the processed surface effect is better.
Shallow plane processing: mainly the size of the camera on the bottom surface, the surface of the camera is relatively flat, and the processing method is more suitable for this surface.
Surround equidistant machining: The camera's fillet is machined to the size, the resulting tool path can be adjusted very dense, smooth, and the rounded corners are better.
Through the above processing methods, the entire shape of the mobile phone can be finally processed, and the upper and lower simulation effects are shown in FIG. 15 and FIG. 16.
Figure 15
Figure 16
3. Conclusion
This paper aims at three-dimensional solid modeling of mobile phones with complex curved surface shape through UG, using MasterCAM to plan the processing trajectory of the mobile phone, processing simulation, and generating NC program, and complete the physical processing of mobile phone in XH714D four-axis machining center. The accuracy of the mobile phone entity is relatively high, and it can be seen that the selected path of the tool is relatively successful, and the error after processing is within the allowable range. The results show that the method is feasible and has guiding significance for the modeling and processing of complex surfaces.
Related links: Mobile body modeling based on four-axis machine tools
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