Taking the special-shaped workpiece of the magnetic levitation rail row as an example, this article introduces a processing method and clamping method for special-shaped asymmetric cross-section profiles. Through process innovation, the method of centralized processes and divided workstations is used to achieve multi-faceted special-shaped workpieces simultaneously in one clamping. Processing not only ensures the processing accuracy of the workpiece surface and hole groups, but also greatly improves production efficiency and processing quality.
01
Preface
High-speed maglev vehicles have the advantages of zero pollution, no need for fuel, no harmful gas emissions, low noise, comfortable ride, strong climbing ability, and fast acceleration and deceleration. Maglev rails are line equipment that carry maglev vehicles. The vehicles achieve smooth operation by being suspended on the rails. The traditional production of magnetic levitation rail rows requires manual clamping and positioning, and uses single-station processing operations. The production takes a long time and requires a lot of equipment and labor. Not only is the production efficiency low, but the labor intensity of the operators is high, and the processing methods need to be improved urgently. The main component of the magnetic levitation rail row is a special-shaped workpiece, which is a special-shaped asymmetrical cross-section profile. There are no formed products in China. Not only are the models different, but the surface and hole groups of the workpiece require high processing accuracy. The length of a special-shaped workpiece is 13m, and it takes at least 9 hours to complete the processing using traditional methods. After the process innovation, the processing time of a single special-shaped workpiece is only about 30 minutes, which not only greatly improves the efficiency, but also achieves higher manufacturing precision.
02
Special-shaped workpiece processing content and requirements
The shape of the special-shaped workpiece is complex. The surface to be processed and its serial number are shown in Figure 1, and the hole processing section is shown in Figure 2. There are a total of 11 surfaces from surface 1 to surface 11, all of which need to be processed. The processing volume is 3~5mm, and the required surface roughness value Ra=6.3μm. The longest workpiece length is 13m, and the number of workpieces reaches 13,000. It not only has many processing surfaces, but also has a large batch size. If processed face by face, not only the processing efficiency is low, but also due to multiple clampings, the processing accuracy is difficult to guarantee.
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Figure 1: Special-shaped workpiece needs to be processed and its serial number
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Figure 2: Processing section of special-shaped workpiece hole
03
processing method
Due to the special shape of this workpiece, many surfaces need to be processed, and the processing accuracy and geometric tolerance requirements are very high. For this reason, the method of centralized processing procedures, simultaneous processing of multiple surfaces in one clamping, and divided work stations are used for processing.
3.1 Station 1
Station 1 is shown in Figure 3. The workpiece is clamped at one time and faces 1, 11, 10 and 9 are processed at the same time. A powerful electromagnetic chuck is used during processing, with surface 4 as the positioning reference surface and surface 8 as the auxiliary support surface. A hydraulic cylinder and spherical clamping rod combination tooling is used between surfaces 3 and 5 to clamp the workpiece. One end of the tooling is equipped with The other end of the hydraulic cylinder is equipped with a spherical pressing rod. The piston rod presses against surface 3 under the action of hydraulic oil. The workpiece moves in the direction of surface 3 until surface 5 is close to the spherical pressing rod. Surfaces 1 and 9 are processed using two side milling power heads installed on the machine tool column, and surfaces 10 and 11 are processed using milling power heads installed on the front and rear beams of the machine tool. The processing of face 1, face 11, face 10 and face 9 is shown in Figure 4.
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Figure 3 Workstation 1
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Figure 4: Processing of face 1, face 11, face 10 and face 9
1. 6-Side milling power head 2-Beam 3-Spindle one 4-Spindle two 5-Transmission screw 7-Column 8-Chip conveyor 9-Positioning and clamping tooling 10-Workpiece 11-Workbench 12-Lathe bed
3.1 Station 2
Station 2 is shown in Figure 5. The workpiece is clamped at one time and faces 2 to 8 are processed at the same time, a total of 7 faces. A powerful electromagnetic chuck is used during processing, with surface 11 as the positioning reference surface, surface 10 as the auxiliary support surface, and a hydraulic cylinder and positioning block combination tooling is used between surfaces 1 and 9 to clamp the workpiece. Surfaces 2, 4, and Surfaces 6 and 8 are processed by three milling power heads installed on the side of the workbench. Surfaces 3, 5 and 7 are processed by a combined tool and milling power head installed at the front end with supports at both ends across the workbench. The processing of faces 2 to 8 is shown in Figure 6.
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Figure 5 Station 2
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Figure 6: Processing of surfaces 2 to 8
1-Workbench 2-Combined tool support device 3-Workbench driving device 4-Driving shaft 5-Lathe bed
6-Processing device for Surface 2, Surface 4, Surface 6 and Surface 8 7-Processing device for Surface 3, Surface 5 and Surface 7
3.3 Station three
The workpiece is clamped on the machine tool workbench at one time using the clamping tool, and the tool magazine and tool changing manipulator are used to process holes of different diameters. The clamping principle for processing is similar to that of station two.
04
Conclusion
This article takes the magnetic levitation rail row special-shaped workpiece as an example to improve the process. The improved processing and clamping method can not only meet the requirements of mass production, but also greatly improve production efficiency and processing quality. The innovations and experiences are summarized as follows.
1) All surfaces and full lengths of special-shaped workpieces need to be machined. To this end, the methods of process concentration, division of work stations and simultaneous processing of multiple surfaces are adopted.
2) The surface to be processed after the process is concentrated cannot be used as a clamping and positioning surface during processing to avoid interference.
3) When processing special-shaped workpieces on multiple sides, the clamping method of bottom electromagnetic clamping, side positioning and auxiliary support on both sides is used. The powerful electromagnetic chuck, hydraulic cylinder and positioning block combination tooling is used to achieve rapid positioning and clamping.
