Cathode evaluation criterion and design method for sleeve-shaped electrolytic machining tool

Abstract

The invention discloses an evaluation criterion and a design method for a cathode of a sleeve-shaped electrolytic machining tool, and belongs to the technical field of electrolytic machining. A tool cathode is deformed under the pressure action of electrolyte, and the stability and machining precision of a flow field are affected. According to the method, a tool cathode is preliminarily designed based on the overall component diameter, the blade number and the structure size; tool cathode deformation and the proportion of low-flow-velocity points in a machining area are set as evaluation criteria; according to influence factors of tool cathode deformation, a multi-factor orthogonal test table is designed, and through fluid-solid coupling simulation analysis, the tool cathode deformation amount and the proportion of low-flow-velocity points in a machining area are obtained; and determining the influence degree of each factor on the deformation of the tool cathode based on a multi-factor orthogonal test method, and sequentially optimizing the tool cathode. According to the method, the deformation of the tool cathode and the proportion of the low-flow-velocity points in the machining area are controlled within a certain range through optimal design of the sleeve-shaped electrolytic machining tool cathode, so that the sleeve-shaped electrolytic machining precision and the machining stability are improved.

Description

Technical Field

[0001] The invention relates to a cathode evaluation criterion and a design method for a sleeve-shaped electrolytic machining tool, belonging to the technical field of electrolytic machining. Background Art

[0002] As the heart of the aircraft, the aircraft engine is a highly complex and precise structure. The engine is composed of blades of different sizes. Engine blades are mostly made of difficult-to-process materials such as titanium alloy and high-temperature alloy. The traditional processing method has problems such as difficult cutting, large stress deformation, and high tool loss. Electrolytic processing is widely used in the manufacture of aircraft engine blades due to its wide processing range and no cathode loss.

[0003] On this basis, some researchers have designed a device for electrolytic machining of inward blades of multi-stage rectifier stators in the patent "Device and method for electrolytic machining of inward blades of multi-stage rectifier stators" (application number CN201911298730.3, inventors Zhu Dong, Zhang Chao, and Zhu Di), which can meet the needs of electrolytic machining of inward blades. In the patent "Dual-blade electrolytic machining device and machining method" (application number CN202010425084.9, inventors Zhu Dong, Zhang Xiaobo, and Lin Jiahao), an insulating sleeve in the cathode seat and a protective sleeve for adjacent blades on both sides are designed to prevent stray corrosion of the blades being machined and the machined blades. In the patent "Sleeve-shaped electrolytic machining device with liquid-increasing holes to enhance liquid supply" (application number CN202211131128.2, inventors Zhang Chaowu, Gao Yu, Pan Siyuan, Ding Jinming, Xie Wei, Li Guoqing, and Zhang Liou), a sleeve-shaped electrolytic machining device with liquid-increasing holes to enhance liquid supply was designed. The design of the liquid-increasing holes supplements the liquid supply to the low-speed area of ​​the flow field in the machining area, improves the uniformity and stability of the flow field, and helps to achieve high-speed sleeve-shaped electrolytic machining of parts.

[0004] Sleeve electrolytic machining is a method of obtaining blades by corroding the specified area of ​​the workpiece end face with a cathode sheet. The inner cavity size of the cathode sheet is designed according to the size of the blade to be machined. During the machining process, the workpiece is connected to the positive pole of the power supply, the anode is continuously dissolved, and the cathode sheet is connected to the negative pole of the power supply. The cathode sheet is continuously fed to remove the material around the blade, thereby forming a blade shape to complete the machining. In order to protect the machined blade, an insulating sleeve structure is designed in the middle of the cathode. The deformation of the tool cathode under the impact of the electrolyte will affect the machining accuracy of the blade.

[0005] In sleeve electrolytic machining, low electrolyte flow rate in the machining area can easily lead to lack of liquid, making it difficult for the electrolyte to carry away the electrolytic products, resulting in spark short circuit. Therefore, the most important thing in sleeve electrolytic machining is the design of the tool cathode, which must ensure that the deformation of the tool cathode during machining meets the design criteria, the flow field in the machining area is uniform, and the proportion of low flow rate points is controlled within a certain range. Summary of the invention

[0006] The invention proposes a sleeve-shaped electrolytic machining tool cathode evaluation criterion and design method, and reduces the deformation of the tool cathode through orthogonal test and fluid-solid coupling simulation, thereby improving the accuracy of sleeve-shaped electrolytic machining.

[0007] A sleeve-shaped electrochemical machining tool cathode evaluation criteria and design method, characterized by comprising the following process: Step 1: Preliminary design of the tool cathode according to the structural dimensions and channel width of the sleeve-shaped electrolytic machining blade. The tool cathode consists of a cathode sheet, a cathode base, and an insulating sleeve, wherein a reinforcing rib is provided on the outside of the insulating sleeve; Step 2: During processing, the electrolyte flows between the tool cathodes and generates pressure on the tool cathode, causing the tool cathode to deform. The factors that affect the deformation of the cathode sheet, cathode base and insulating sleeve and the proportion of low flow rate points in the processing area include: cathode sheet thickness, cathode base side wall thickness, insulating sleeve thickness, number of reinforcing ribs, reinforcing rib width, and reinforcing rib position. The above-mentioned influencing factors are used as orthogonal test parameters to design a multi-factor multi-level orthogonal test table. Step 3: According to the multi-factor orthogonal test table, the corresponding tool cathode model is established, and the fluid-solid coupling simulation is performed on each model to obtain the corresponding cathode sheet deformation x1, cathode base deformation x2, insulation sleeve deformation x3 and the proportion of low flow rate points in the processing area a%; Among them, x1, x2, and x3 refer to the deformation of the cathode sheet, cathode base, and insulation sleeve at the maximum deformation point respectively; x1, x2, and x3 must all be less than D / 10, where D refers to the blade design accuracy; The calculation method of the percentage of low flow rate points in the processing area a% is as follows: A points are evenly selected in the processing area, and the points where the fluid motion state is laminar according to the Reynolds number are low flow rate points. The percentage of low flow rate points is the percentage of low flow rate points in the total number of points A; the percentage of low flow rate points in the processing area a% must be less than the set value b%, and the set value b% is determined according to the tool cathode feed speed, where the faster the feed speed, the smaller the set value b%; Step 4: According to the orthogonal test results, the deformation of the cathode sheet, the deformation of the cathode base, the deformation of the insulating sleeve, and the proportion of low flow rate points in the processing area are analyzed respectively to obtain the influence of a single factor on the deformation of the cathode sheet, the deformation of the cathode base, the deformation of the insulating sleeve, and the proportion of low flow rate points in the processing area, and the influence of multiple factors in the orthogonal table on the deformation of the cathode sheet, the deformation of the cathode base, the deformation of the insulating sleeve, and the proportion of low flow rate points in the processing area are ranked. If the two types of factors have the same influence on the cathodes of different tools, the influencing factors of the parts with larger deformation in the tool cathode are ranked first; Step 5: According to the influence of multiple factors, first select the factor with the greatest influence, and combine the influence law of the factor to change the factor to reduce the deformation of the cathode sheet, until the deformation of the cathode base, the deformation of the insulation sleeve, or the proportion of low flow rate points in the processing area does not meet the evaluation criteria, the optimization of the factor is completed, and then the remaining factors are optimized in turn; Step 6: During the optimization process, the deformation of the cathode sheet, the deformation of the cathode base, the deformation of the insulating sleeve and the proportion of low flow rate points in the processing area all meet the design criteria, that is, the deformation of the cathode sheet, the deformation of the cathode base and the deformation of the insulating sleeve are controlled within D / 10, and the proportion of low flow rate points in the processing area is less than b%; Step 7: After the design is completed, the tool cathode structure and size of the sleeve electrolytic machining corresponding to the blade size are obtained.

[0008] The beneficial effects of the present invention are: 1. The present invention proposes a sleeve-shaped electrolytic machining tool cathode design method. Based on the traditional sleeve-shaped electrolytic machining tool cathode structure, a multi-factor orthogonal test table is designed according to the factors affecting the tool cathode deformation during the electrolytic machining process. A model is established and a fluid-solid coupling simulation analysis is carried out to obtain the corresponding tool cathode deformation and the proportion of low flow rate points in the machining area. The tool cathode can be accurately designed, and the accurate and rapid design of the tool cathode is achieved, which has strong versatility.

[0009] 2. The tool cathode deformation and the proportion of low flow velocity points in the processing area are proposed as evaluation criteria. The tool cathode deformation and the uniformity of the flow field in the processing area are comprehensively considered to improve the design accuracy.

[0010] 3. According to the orthogonal test results, the deformation of the cathode sheet, the deformation of the cathode base, the deformation of the insulation sleeve, and the proportion of low flow rate points in the processing area are analyzed respectively, and the influence of a single factor on the deformation of the tool cathode and the proportion of low flow rate points in the processing area, and the influence of multiple factors on the deformation of the tool cathode and the proportion of low flow rate points in the processing area are obtained, providing accurate and efficient direction for optimizing the cathode BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 A flow chart of a sleeve-shaped electrolytic machining tool cathode evaluation criteria and design method provided by an embodiment of the present invention; Figure 2 It is a schematic diagram of the tool cathode sleeve; Label names in the figure: 1 cathode base, 2 insulating sleeves, 3 Insulation sleeve cavity, 4 workpieces, 5. Liquid inlet width, 6 cathode sheet, 7 reinforcing ribs, S 1 Insulation sleeve thickness,S Cathode base wall thickness; d Width of reinforcement rib; S 2 (i.e. the length of the reinforcing rib from the lower end of the insulating sleeve) Reinforcing rib position, Δ s External side clearance, H Insulation sleeve cavity height, WChannel Width . DETAILED DESCRIPTION

[0012] The design process of the present invention will be described below in conjunction with the accompanying drawings, as follows: Step 1: Preliminary design of the tool cathode according to the structural dimensions and channel width of the sleeve-shaped electrolytic machining blade. The tool cathode consists of a cathode sheet, a cathode base, and an insulating sleeve, wherein a reinforcing rib is provided on the outside of the insulating sleeve; Step 2: During processing, the electrolyte flows between the tool cathodes and generates pressure on the tool cathode, causing the tool cathode to deform. The factors that affect the deformation of the cathode sheet, cathode base and insulating sleeve and the proportion of low flow rate points in the processing area include: cathode sheet thickness, cathode base side wall thickness, insulating sleeve thickness, number of reinforcing ribs, reinforcing rib width, and reinforcing rib position. The above-mentioned influencing factors are used as orthogonal test parameters to design a multi-factor multi-level orthogonal test table. Step 3: According to the multi-factor orthogonal test table, the corresponding tool cathode model is established, and the fluid-solid coupling simulation is performed on each model to obtain the corresponding cathode sheet deformation x1, cathode base deformation x2, insulation sleeve deformation x3 and the proportion of low flow rate points in the processing area a%; Among them, x1, x2, and x3 refer to the deformation of the cathode sheet, cathode base, and insulation sleeve at the maximum deformation point respectively; x1, x2, and x3 must all be less than D / 10, where D refers to the blade design accuracy; The calculation method of the percentage of low flow rate points in the processing area a% is as follows: A points are evenly selected in the processing area, and the points where the fluid motion state is laminar according to the Reynolds number are low flow rate points. The percentage of low flow rate points is the percentage of low flow rate points in the total number of points A; the percentage of low flow rate points in the processing area a% must be less than the set value b%, and the set value b% is determined according to the tool cathode feed speed, where the faster the feed speed, the smaller the set value b%; Step 4: According to the orthogonal test results, the deformation of the cathode sheet, the deformation of the cathode base, the deformation of the insulating sleeve, and the proportion of low flow rate points in the processing area are analyzed respectively to obtain the influence of a single factor on the deformation of the cathode sheet, the deformation of the cathode base, the deformation of the insulating sleeve, and the proportion of low flow rate points in the processing area, and the influence of multiple factors in the orthogonal table on the deformation of the cathode sheet, the deformation of the cathode base, the deformation of the insulating sleeve, and the proportion of low flow rate points in the processing area are ranked. If the two types of factors have the same influence on the cathodes of different tools, the influencing factors of the parts with larger deformation in the tool cathode are ranked first; Step 5: According to the influence of multiple factors, first select the factor with the greatest influence, and combine the influence law of the factor to change the factor to reduce the deformation of the cathode sheet, until the deformation of the cathode base, the deformation of the insulation sleeve, or the proportion of low flow rate points in the processing area does not meet the evaluation criteria, the optimization of the factor is completed, and then the remaining factors are optimized in turn; Step 6: During the optimization process, the deformation of the cathode sheet, the deformation of the cathode base, the deformation of the insulating sleeve and the proportion of low flow rate points in the processing area all meet the design criteria, that is, the deformation of the cathode sheet, the deformation of the cathode base and the deformation of the insulating sleeve are controlled within D / 10, and the proportion of low flow rate points in the processing area is less than b%; Step 7: After the design is completed, the tool cathode structure and size of the sleeve electrolytic machining corresponding to the blade size are obtained.

Claims

1. A cathode evaluation criterion and design method for a sleeve-shaped electrolytic machining tool, characterized in that The process includes: Step 1: Preliminary design of the tool cathode according to the structural dimensions and channel width of the sleeve-shaped electrolytic machining blade. The tool cathode consists of a cathode sheet, a cathode base, and an insulating sleeve, wherein a reinforcing rib is provided on the outside of the insulating sleeve; Step 2: During processing, the electrolyte flows between the tool cathodes and generates pressure on the tool cathode, causing the tool cathode to deform. The factors that affect the deformation of the cathode sheet, cathode base and insulating sleeve and the proportion of low flow rate points in the processing area include: cathode sheet thickness, cathode base side wall thickness, insulating sleeve thickness, number of reinforcing ribs, reinforcing rib width, and reinforcing rib position. The above-mentioned influencing factors are used as orthogonal test parameters to design a multi-factor multi-level orthogonal test table. Step 3: According to the multi-factor orthogonal test table, the corresponding tool cathode model is established, and the fluid-solid coupling simulation is performed on each model to obtain the corresponding cathode sheet deformation x1, cathode base deformation x2, insulation sleeve deformation x3 and the proportion of low flow rate points in the processing area a%; Among them, x1, x2, and x3 refer to the deformation of the cathode sheet, cathode base, and insulation sleeve at the maximum deformation point respectively; x1, x2, and x3 must all be less than D / 10, where D refers to the blade design accuracy; The calculation method of the percentage of low flow rate points in the processing area a% is as follows: A points are evenly selected in the processing area, and the points where the fluid motion state is laminar according to the Reynolds number are low flow rate points. The percentage of low flow rate points is the percentage of low flow rate points in the total number of points A; the percentage of low flow rate points in the processing area a% must be less than the set value b%, and the set value b% is determined according to the tool cathode feed speed, where the faster the feed speed, the smaller the set value b%; Step 4: According to the orthogonal test results, the deformation of the cathode sheet, the deformation of the cathode base, the deformation of the insulating sleeve, and the proportion of low flow rate points in the processing area are analyzed respectively to obtain the influence of a single factor on the deformation of the cathode sheet, the deformation of the cathode base, the deformation of the insulating sleeve, and the proportion of low flow rate points in the processing area, and the influence of multiple factors in the orthogonal table on the deformation of the cathode sheet, the deformation of the cathode base, the deformation of the insulating sleeve, and the proportion of low flow rate points in the processing area are ranked. If the two types of factors have the same influence on the cathodes of different tools, the influencing factors of the parts with larger deformation in the tool cathode are ranked first; Step 5: According to the influence of multiple factors, first select the factor with the greatest influence, and combine the influence law of the factor to change the factor to reduce the deformation of the cathode sheet, until the deformation of the cathode base, the deformation of the insulation sleeve, or the proportion of low flow rate points in the processing area does not meet the evaluation criteria, the optimization of the factor is completed, and then the remaining factors are optimized in turn; Step 6: During the optimization process, the deformation of the cathode sheet, the deformation of the cathode base, the deformation of the insulating sleeve and the proportion of low flow rate points in the processing area all meet the design criteria, that is, the deformation of the cathode sheet, the deformation of the cathode base and the deformation of the insulating sleeve are controlled within D / 10, and the proportion of low flow rate points in the processing area is less than b%; Step 7: After the design is completed, the tool cathode structure and size of the sleeve electrolytic machining corresponding to the blade size are obtained.

2. The cathode evaluation criteria and design method of sleeve-shaped electrochemical machining tool according to claim 1, characterized in that: The A in the step 3 is not less than 10,000.

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