A method for electrolytic roughening, array grinding and polishing and finishing of a blisk

Abstract

A method for electrolytic roughing, array grinding and polishing, and finishing of integral bladed disks includes the following steps: performing electrolytic roughing of the integral bladed disk; controlling the size of the superhard grinding wheel as follows: during array grinding, selecting appropriate superhard grinding wheel size and grinding parameters according to different zones; the blade grinding trajectory can be performed using helical circumferential grinding or longitudinal grinding to ensure uniform removal; during array polishing, selecting appropriate polishing tools according to different zones; during array polishing, using appropriate array polishing parameters; during array polishing, to ensure the inlet and outlet edge profiles, longitudinal polishing can be performed along the inlet and outlet edge direction; the vibratory finishing equipment is an islandless vibratory finishing machine. Advantages of this invention: reducing processing costs and time during batch production of integral bladed disks, ensuring the processing quality of integral bladed disk parts, and ensuring that their dimensional accuracy, positional accuracy, and inlet and outlet edge arc shape accuracy meet design requirements; it is a high-quality, high-efficiency, and low-cost processing method for integral bladed disks.

Description

Technical Field

[0001] This invention relates to the field of aero-engine technology, and in particular to a method for electrolytic roughing, array grinding and polishing, and finishing strengthening of an integral bladed disk. Background Technology

[0002] As a critical component of advanced aero-engines, the integral bladed disk (IBD) directly affects the service performance and lifespan of the aero-engine due to its dimensions, positional accuracy, and surface quality. The IBD of high-temperature alloy compressors has a complex structure, with curved blades in a single cantilever configuration. The blades obstruct each other, the blade body is thin and uneven, and the flow channels are deep and narrow. It requires high geometric accuracy and surface quality, and the material has high hardness, making it extremely difficult to manufacture.

[0003] Currently, CNC milling is the primary method for machining integral bladed disks for aero-engines in my country. However, CNC milling of high-temperature alloys involves significant material removal, rapid tool wear, and high processing costs. Furthermore, the relatively weak rigidity of the integral bladed disk blades leads to substantial deviations between actual and theoretical dimensions, resulting in substandard inlet and outlet edge shapes. Additionally, CNC milling leaves noticeable tool marks, necessitating polishing and vibratory finishing for removal.

[0004] In recent years, linear friction welding has also been gradually applied to the processing of integral bladed disks. Linear friction welding has high requirements for the thermoplasticity of metal materials and is not suitable for processing parts made of nickel-based, iron-based and other materials. It is mainly suitable for the manufacturing of integral bladed disks for titanium alloy fans.

[0005] Compared with milling, linear friction welding and other technologies, precision electrolytic integral bladed disks have certain advantages, such as no tool wear, low processing cost, and no contact between tools and workpieces, which avoids problems such as vibration, deformation and residual stress. However, the precision electrolytic machining technology for integral bladed disks in China is not yet mature and has not been widely applied. Summary of the Invention

[0006] Existing machining processes for high-temperature alloy integral bladed disks involve controlling dimensional and positional accuracy through CNC milling, and improving surface milling marks and roughness through polishing and vibratory finishing. However, given the high cost of milling tools, low machining efficiency, and the tendency for actual dimensional deviations to exceed tolerances, as well as the difficulty in guaranteeing the shape of the inlet and outlet edges, this invention provides a method for electrolytic roughing, array grinding and polishing, and finishing of integral bladed disks. This method ultimately achieves the fabrication of integral bladed disks with high dimensional accuracy, high positional accuracy, and high accuracy in the arc shape of the inlet and outlet edges.

[0007] This invention provides a method for electrolytic roughing, array grinding and polishing, and finishing of an integral bladed disk, characterized by the following steps:

[0008] 1) Perform electrolytic rough machining of the integral bladed disk;

[0009] 2) The method for controlling the size of superhard grinding wheels is as follows:

[0010] 3) During array grinding, select appropriate superhard grinding wheel size and grinding parameters according to different zones;

[0011] 4) During array grinding, the blade grinding trajectory can be carried out using spiral peripheral grinding or longitudinal grinding to ensure uniform removal.

[0012] 5) When polishing the array, select the appropriate polishing tool according to different zones;

[0013] 6) When performing array polishing, use appropriate array polishing parameters;

[0014] 7) During array polishing, in order to ensure that the air intake and exhaust edge surfaces can be polished longitudinally along the air intake and exhaust edge direction;

[0015] 8) The vibratory finishing equipment is an islandless vibratory finishing machine;

[0016] 9) New abrasives should be pretreated before use, and used after vibrating in a finishing machine for 3 hours.

[0017] The specific process of performing electrolytic roughing of the integral bladed disk is as follows:

[0018] The electrolytic roughing process is carried out using a combination of a bushing cathode and a profile split cathode. The integral bladed disk blank is installed on the worktable of the electrolytic machine tool, and the electrolysis parameters are set. First, the bushing cathode is used to perform electrolytic roughing of the blank. Then, the profile split cathode is used to perform electrolytic shaping of the bladed disk body with roughing. After electrolytic shaping, the overall bladed disk allowance is controlled within 0.3-0.5mm. Finally, a coordinate measuring machine is used to inspect the overall bladed disk.

[0019] Then, based on the structural characteristics of the integral bladed disk and blade ring parts, they are rationally partitioned, and the integral bladed disk machining model is divided into three areas: the flow channel area, the blade root area, and the blade body area. UG software is used to generate CNC programs, and the machining programs are optimized based on the measurement results of the machined parts. The parts are clamped on an array grinding and polishing machine, and appropriate superhard grinding wheels are selected to perform array rough and fine grinding on the flow channel area, blade root area, and blade body area respectively. During the machining process, the size of the superhard grinding wheels is strictly controlled to ensure the machining accuracy and consistency of the array grinding of the integral bladed disk blades.

[0020] The integral bladed disk machining model is divided into seven areas: flow channel area, blade basin and blade root, blade back and blade root, blade basin area, blade back area, air intake edge area, and air exhaust edge area. UG software is used to generate a CNC polishing program, and the integral bladed disk is subjected to rough and fine polishing processing by area using the corresponding polishing tools and polishing parameters on an array grinding and polishing machine.

[0021] Integrated finishing and strengthening processing is carried out; stainless steel disc-shaped abrasive is placed in a vibratory finishing equipment and abrasive slurry is sprayed for integrated vibratory finishing and strengthening processing. Vibration time: 1-2 hours for the front side and 1-2 hours for the back side; vibration frequency: 50 Hz; abrasive slurry spraying time: 10 minutes for the front side and 10 minutes for the back side; finishing and strengthening parameters can also be determined by experiments.

[0022] The method for controlling the size of the superhard grinding wheel is as follows: First, the outer diameter of the superhard grinding wheel is uniformly ground. A conventional grinding machine is used to drive a large-diameter diamond repair tool to grind the outer diameter of the small-diameter superhard grinding wheel. The grinding amount is 0.01-0.03mm. The circular runout deviation of the ground wheel after the grinding is within 0.02mm.

[0023] The maximum outer diameter of the superhard grinding wheel during rotation was measured using a non-contact point laser. The test results were analyzed, and grinding wheels with a maximum outer diameter deviation within 0.03 mm were retained for array grinding and polishing.

[0024] In the initial stage of processing, the superhard grinding wheel is inspected online every 7 integral impeller blades processed to measure the maximum outer diameter of the grinding wheel. The grinding and polishing process is compensated according to the wear amount before processing the next impeller blade. Through several inspections, the wear pattern of the superhard grinding wheel can be explored and the compensation parameters can be solidified. After that, it is no longer necessary to inspect the grinding wheel every 7 integral impeller blades processed. Instead, random inspection can be carried out after a certain batch is processed.

[0025] During array grinding, appropriate superhard grinding wheel sizes and grinding parameters are selected according to different zones. For rough grinding, the spindle speed is 20,000-30,000 r / min, the feed rate is 500-1000 mm / min, and the depth of cut is 0.05-0.1 mm. For finish grinding, the machining parameters are a spindle speed of 20,000-30,000 r / min, a feed rate of 500-1000 mm / min, and a depth of cut of 0.01-0.05 mm. The blade grinding trajectory can be performed using helical circumferential grinding or longitudinal grinding, but the material removal is uniform.

[0026] The array polishing process involves selecting appropriate polishing tools based on different zones; using rubber-based flexible polishing wheels; the polishing wheel base is made of elastic rubber, with an outer abrasive layer, possessing a certain degree of flexibility to achieve adaptive processing during polishing; 400#-800# polishing wheels are used for rough polishing, while 1500#-2000# polishing wheels can be used for fine polishing.

[0027] For array polishing, use appropriate array polishing parameters; for rough polishing, set the spindle speed to 4000-6000 r / min, feed speed to 1000-3000 mm / min, and preload to 0.1-0.3 mm; for fine polishing, set the spindle speed to 4000-6000 r / min, feed speed to 800-2000 mm / min, and preload to 0.1-0.3 mm; during array polishing, to ensure the profile of the air intake and exhaust edges, perform longitudinal polishing along the direction of the air intake and exhaust edges.

[0028] The vibratory finishing equipment is an islandless vibratory finishing machine. New abrasives need to be pretreated before use, and vibrated in the finishing machine for 3 hours.

[0029] Compared with the prior art, the advantages of this invention are:

[0030] The method for electrolytic roughing, array grinding and polishing, and surface finishing of integral bladed disks (IBDs) described in this invention significantly reduces the processing cost and overall processing time for batch production of IBDs, while ensuring the processing quality of IBD components, guaranteeing that their dimensional accuracy, positional accuracy, and the accuracy of the inlet and outlet edge arc shapes meet design requirements. This is a novel, high-quality, high-efficiency, and low-cost processing method for IBDs. Furthermore, this invention has broad market demand and application prospects for improving the surface quality of IBD structural components in gas turbines. Attached Figure Description

[0031] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments:

[0032] Figure 1 Schematic diagram of the integral bladed disk after rough grooving

[0033] Figure 2 Schematic diagram of the underside of the leaf disc

[0034] Figure 3 Schematic diagram of leaf disc and leaf basin

[0035] Figure 4 Blade disk coordinate measuring machine results

[0036] Figure 5 Results of residual force test on the leaf blade. Detailed Implementation

[0037] The present invention will be further explained below with reference to specific implementation schemes, but it is not limited to the present invention. The structures, proportions and sizes shown in the accompanying drawings are only used to complement the content disclosed in the specification, so as to enable those skilled in the art to understand and read, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modification to the structure, change in the proportions or adjustment of the size, without affecting the effects and objectives that the present invention can produce, still falls within the scope of the technical content disclosed in the present invention.

[0038] The 7-stage integral bladed disk blank was mounted on the electrolysis machine tool worktable, and the electrolysis parameters were set. Rough grooving of the blank was performed using a bushing cathode. Then, a contour-following split cathode was used to electrolytically refine the blade body of the roughly grooved integral bladed disk. Afterwards, a coordinate measuring machine was used to inspect the integral bladed disk. The inspection showed that the remaining material of the integral bladed disk was within 0.3-0.5mm, allowing for subsequent processing. After the rough electrolytic shaping... Figure 1 As shown.

[0039] Then, the overall bladed disk machining model was divided into three areas: the flow channel area, the blade root area, and the blade body area. A CNC program was generated using UG software, and the machining program was optimized. The part was clamped on an array grinding and polishing machine, with the spindle speed set to 30,000 r / min, feed rate 1000 mm / min, and depth of cut 0.1 mm. Superhard grinding wheels with r = 1.5 mm, D = 20.0 mm, and grit size 200# were used for array rough grinding of the flow channel and blade body areas. Superhard grinding wheels with r = 1.5 mm, D = 12.0 mm, and grit size 200# were used for array rough grinding of the blade root area. Eight blades were machined at a time. After machining 56 blades (each superhard grinding wheel completed rough grinding of 7 blades), an online inspection was performed on all superhard grinding wheels, measuring a wear of 0.007 mm. The machining program was compensated based on the wear amount until the entire bladed disk was rough ground.

[0040] Next, array grinding is performed. The spindle speed is set at 30,000 r / min, the feed rate at 1000 mm / min, and the depth of cut at 0.02 mm. Pre-treated superhard grinding wheels with r=1.5 mm, D=20.0 mm, and grit size of 300# are used for array grinding of the flow channel and blade areas. Pre-treated superhard grinding wheels with r=1.5 mm, D=12.0 mm, and grit size of 300# are used for array grinding of the blade root area. Eight blades are processed at a time. After processing 56 blades (7 blades per superhard grinding wheel), an online inspection is performed on all grinding wheels, and the machining program is compensated based on the wear amount until the entire impeller is finished.

[0041] Next, rough polishing of the array is performed. The overall bladed disk machining model is divided into seven regions: the flow channel region, the blade base and blade root, the blade back and blade root, the blade base region, the blade back region, the intake side region, and the exhaust side region, as follows: Figure 2 , 3As shown. A CNC polishing program was generated using UG software, setting the spindle speed to 4000 r / min, feed rate to 1000 mm / min, and preload to 0.2 mm. A 500# rubber-based polishing wheel with r = 1.5 mm and D = 20.0 mm was used to perform array rough polishing on the flow channel area, blade base area, blade back area, intake edge area, and exhaust edge area. A 500# rubber-based polishing wheel with r = 1.5 mm and D = 12.0 mm was used to perform array rough polishing on the blade base and blade back / root areas. Eight blades were polished at a time until the entire bladed disk was rough polished.

[0042] Next, array polishing is performed. The spindle speed is set at 4000 r / min, the feed rate at 1000 mm / min, and the preload at 0.2 mm. A 2000# rubber-based polishing wheel with r=1.5 mm and D=20.0 mm is used to perform array polishing on the flow channel area, blade base area, blade back area, inlet edge area, and exhaust edge area. A 2000# rubber-based polishing wheel with r=1.5 mm and D=12.0 mm is used to perform array polishing on the blade base and blade back / root areas. Eight blades are polished at a time until the entire bladed disk is polished.

[0043] Afterwards, integrated finishing and strengthening processing is carried out. An islandless vibratory finishing equipment is used, with an integral bladed disk installed, and stainless steel disc-shaped abrasive is placed in it for integrated vibratory finishing and strengthening processing. Vibration time: 1 hour on the front side and 1 hour on the back side; vibration frequency: 50 Hz; abrasive spraying time: 10 minutes on the front side and 10 minutes on the back side.

[0044] Then, a coordinate measuring machine was used for measurement. Figure 4 The coordinate measuring machine (CMM) results are all within the tolerance zone, and the overall bladed disk dimensions meet the design requirements. A portable roughness tester was used to measure the surface roughness, which is Ra 0.4 μm, meeting the design requirements. The residual force along the depth direction was also measured. Figure 5 As shown, the residual pressure on the surface reaches over -600MPa. The residual pressure can inhibit the initiation of fatigue cracks to a certain extent. This method can achieve the preparation of integral bladed disks with high shape accuracy and high surface quality. At the same time, the processing time of integral bladed disks using this method is only half that of CNC milling integral bladed disks, which greatly improves processing efficiency.

[0045] Matters not covered in this invention are common knowledge.

[0046] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their likenesses.

Claims

1. A method for electrolytic roughing, array grinding and polishing, and surface finishing of an integral bladed disk, characterized in that: Includes the following steps: 1) Perform electrolytic rough machining of the integral bladed disk; 2) Control of the size of the superhard grinding wheel; 3) During array grinding, select the size of the superhard grinding wheel and grinding parameters according to different zones; 4) During array grinding, the blade grinding trajectory can be carried out using spiral peripheral grinding or longitudinal grinding to ensure uniform removal. 5) When polishing the array, select the polishing tool according to different partitions; 6) When performing array polishing, use the array polishing parameters; 7) During array polishing, in order to ensure that the air intake and exhaust edge surfaces can be polished longitudinally along the air intake and exhaust edge direction; 8) The vibratory finishing equipment is an islandless vibratory finishing machine; 9) New abrasives should be pretreated before use, and vibrated in a finishing machine for 3 hours before use; The specific process of performing electrolytic roughing of the integral bladed disk is as follows: The electrolytic roughing process is carried out using a combination of a bushing cathode and a profile split cathode. The integral bladed disk blank is installed on the worktable of the electrolytic machine tool, and the electrolysis parameters are set. First, the bushing cathode is used to perform electrolytic roughing of the blank. Then, the profile split cathode is used to perform electrolytic shaping of the bladed disk body with roughing. After electrolytic shaping, the overall bladed disk allowance is controlled within 0.3-0.5mm. Finally, a coordinate measuring machine is used to inspect the overall bladed disk. Then, based on the structural characteristics of the integral bladed disk and blade ring parts, they are rationally partitioned, and the integral bladed disk machining model is divided into three areas: the flow channel area, the blade root area, and the blade body area. UG software is used to generate CNC programs, and the machining programs are optimized based on the measurement results of the machined parts. The parts are clamped on an array grinding and polishing machine, and superhard grinding wheels are selected to perform array rough and fine grinding on the flow channel area, blade root area, and blade body area respectively. During the machining process, the size of the superhard grinding wheels is strictly controlled to ensure the machining accuracy and consistency of the array grinding of the integral bladed disk blades. The integral bladed disk machining model is divided into seven areas: flow channel area, blade basin and blade root, blade back and blade root, blade basin area, blade back area, air intake edge area, and air exhaust edge area. UG software is used to generate a CNC polishing program, and the integral bladed disk is subjected to rough and fine polishing processing by area using the corresponding polishing tools and polishing parameters on an array grinding and polishing machine. Integrated finishing and strengthening processing is carried out; stainless steel disc-shaped abrasive is placed in a vibratory finishing equipment and abrasive slurry is sprayed for integrated vibratory finishing and strengthening processing. Vibration time: 1-2 hours for the front side and 1-2 hours for the back side; vibration frequency: 50 Hz; abrasive slurry spraying time: 10 minutes for the front side and 10 minutes for the back side; finishing and strengthening parameters can also be determined by experiments.

2. The method for electrolytic roughing, array grinding and polishing, and surface finishing of an integral bladed disk according to claim 1, characterized in that: The method for controlling the size of the superhard grinding wheel is as follows: First, the outer diameter of the superhard grinding wheel is uniformly ground. A grinding machine drives a large-diameter diamond repair tool to grind the outer diameter of the small-diameter superhard grinding wheel. The grinding amount is 0.01-0.03mm. The circular runout deviation of the ground wheel after grinding is within 0.02mm. The maximum outer diameter of the superhard grinding wheel during rotation was measured using a non-contact point laser. The test results were analyzed, and grinding wheels with a maximum outer diameter deviation within 0.03 mm were retained for array grinding and polishing. In the initial stage of processing, the superhard grinding wheel is inspected online every 7 integral impeller blades processed to measure the maximum outer diameter of the grinding wheel. The grinding and polishing process is compensated according to the wear amount before processing the next impeller blade. Through several inspections, the wear pattern of the superhard grinding wheel can be explored and the compensation parameters can be solidified. After that, it is no longer necessary to inspect the grinding wheel every 7 integral impeller blades processed. Instead, random inspection can be carried out after a certain batch is processed.

3. The method for electrolytic roughing, array grinding and polishing, and surface finishing of an integral bladed disk according to claim 1, characterized in that: During array grinding, the size of the superhard grinding wheel and grinding parameters are selected according to different zones. For rough grinding, the spindle speed is 20,000-30,000 r / min, the feed rate is 500-1000 mm / min, and the depth of cut is 0.05-0.1 mm. For finish grinding, the machining parameters are a spindle speed of 20,000-30,000 r / min, a feed rate of 500-1000 mm / min, and a depth of cut of 0.01-0.05 mm. The blade grinding trajectory can be performed using helical circumferential grinding or longitudinal grinding, but the material removal is uniform.

4. The method for electrolytic roughing, array grinding and polishing, and surface finishing of an integral bladed disk according to claim 1, characterized in that: The array polishing process involves selecting polishing tools according to different zones; using rubber-based flexible polishing wheels; the polishing wheel base is elastic rubber with an outer abrasive layer, possessing a certain degree of flexibility to achieve adaptive processing during polishing; 400#-800# polishing wheels are used for rough polishing, and 1500#-2000# polishing wheels are used for fine polishing. For array polishing, the following parameters are used: For rough polishing, set the spindle speed to 4000-6000 r / min, the feed rate to 1000-3000 mm / min, and the preload to 0.1-0.3 mm; For fine polishing, set the spindle speed to 4000-6000 r / min, the feed rate to 800-2000 mm / min, and the preload to 0.1-0.3 mm. During array polishing, to ensure the profile of the air intake and exhaust edges, longitudinal polishing is performed along the direction of the air intake and exhaust edges.

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