Method for manufacturing three-dimensional flow enclosed-type impeller inter-impeller passage and special clamp thereof

Abstract

The invention relates to a method for manufacturing a three-dimensional flow enclosed-type impeller inter-impeller passage and a special clamp thereof. A specially designed and manufactured molding or quasi-molding tool cathode is used for numerical control electrolytic processing to remove most remainder, then a specially designed and manufactured molding or quasi-molding tool electrode is used for numerical control electric spark precision processing to achieve the design requirement, thereby the three-dimensional flow enclosed-type impeller inter-impeller passage that can not be processed resulting from interference of numerical control milling cutter and undercutting can be manufactured, besides, the method has the technical and economical characteristics of high precision and efficiency, and low cost compared with the prior three manufacturing methods of integral casting, divided processing rewelding and numerical control milling.

Description

technical field [0001] The invention belongs to the technical field of ternary flow closed impeller processing, and in particular relates to a special processing method of a ternary flow closed impeller flow channel and a processing device for implementing the processing method. Background technique [0002] With the development of ternary flow theory and its related application technologies, ternary flow impellers have been used more and more in the design of advanced turbine compressor impellers. Since the design of the ternary flow theory is closer to the real motion of the fluid relative to the impeller, the impeller designed and manufactured based on the ternary flow theory has higher working efficiency, which is of great significance for saving energy and reducing pollution. The role of turbomachinery with high flow rate and high energy consumption is more prominent. [0003] In the past two decades, with the development of design and manufacturing technology, on the ...

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Problems solved by technology

[0004] Due to the above-mentioned outstanding advantages of the three-dimensional flow closed impeller, it is expected to be popularized and applied. However, due to its complex blade surface and thin wall, it is easy to deform during the processing process, making its three-dimensional flow blade, or three-dimensional flow blade and disk, The processing of the inter-blade flow channel formed by the cover surface is very difficult, and has become a technical problem that is being tried to solve in the world's advanced manufacturing fields, but has not yet been solved.

[0005] The existing ternary flow closed impeller manufacturing methods include the integral casting method and the three-piece or two-piece welding method, wherein the main process of manufacturing the three-dimensional flow closed impeller by the three-piece welding method is: using a thin alloy steel plate The shaped blades are pressed, and then welded with the wheel cover or the wheel disc to form an integral impeller; while the main process of manufacturing the three-dimensional flow closed impeller by the two-piece welding method is to forge and process the open integral impeller, and then welded with the wheel The disc is welded into a whole impeller; therefore, whether it is the three-piece welding method or the two-piece welding method, the three-dimensional flow closed impeller must be processed through welding in the end, and the blades have springback deformation during the welding process. It is necessary to arrange the necessary heat treatment process in the middle or at the end of the process to uniform the material structure and eliminate the deformation and cutting stress generated in the processing process, or to arrange the precision trimming and polishing process of the blade surface at the end. Therefore, for these two processing methods, the production The process is relatively cumbersome, and the accuracy may not meet the requirements, because the three-piece or two-piece welding method cannot be called integral manufacturing in essence. In order to avoid the technical problem of integrally processing the flow channel between the leaves, the process is first Three major parts (disc, blade, wheel cover) or two major parts (open integral impeller with disc and blade integrated, wheel cover) are processed in one body, and then the three major parts (or two major parts) are welded into a whole ; Although high-precision special welding fixtures are used, it is still difficult to obtain high precision; and the thermal deformation, thermal stress, and even possible cracks that may occur during the welding process will seriously affect the service life and work reliability, especially for those diameters For small three-dimensional flow closed impellers with small blades and thin blades, it is more difficult to meet the design and use requirements with the welding method of three large pieces (or two large pieces)

[0006] The casting method to manufacture the three-dimensional flow closed impeller is a real integral manufacturing method, but the casting method is difficult to obtain high precision, and it is not suitable for the integral impeller of high-strength alloy materials that cannot be cast

[0007] Recently developed the method of CNC milling overall processing of three-dimensional flow closed impeller, and has mastered key technologies such as related programming, cutting tools and cutting process parameters. The main process is: closed impeller forging → CNC turning impeller center positioning hole → CNC Turning the upper and lower end faces of the impeller and the inner and outer profiles → CNC milling the inter-blade channels from the inlet and outlet ends of the inter-blade flow channels respectively (arranged according to the rough and finish machining processes), it can be seen from this that this method is not suitable for those blades with complex profiles and high degree of bending and torsion. The three-dimensional flow closed impeller with large size or small flow channel between blades will inevitably cause tool interference and overcut in the process of milling the flow channel between blades, so that the overall processing of the flow channel cannot be realized; at the same time, for those difficult-to-cut high-strength The ternary flow closed impeller made of alloy material is also very difficult or even impossible to process by CNC milling. Not only the processing efficiency is low, the manufacturing cost is high, but it is also difficult to obtain high precision.

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