Method for processing flow channel holes

Abstract

This application relates to the field of centrifugal compressor technology, specifically disclosing a flow channel hole machining method that can automatically and accurately machine shell openings based on the actual contour of the air duct flow channel, achieving high-precision and smooth connection of the flow channel. The flow channel hole machining method includes: making a rough cut hole at a preset position where the shell and the air duct meet, based on the theoretical design dimensions of the air duct flow channel; pre-assembling and positioning the welded air duct and the shell with the rough cut hole; scanning and measuring the actual contour of the air duct flow channel to acquire contour surface data; processing the contour surface data to generate extended surface data of the air duct flow channel surface facing the direction of the shell rough cut hole; and automatically cutting and grinding the shell rough cut hole based on the extended surface data.

Description

Technical Field

[0001] This application belongs to the field of centrifugal compressor technology, specifically relating to a method for machining flow channel holes. Background Technology

[0002] Centrifugal compressors, as core equipment in fluid machinery, consist of a casing and a blower assembly. The flow channel hole is a key docking structure between the casing and the blower. The machining accuracy of the flow channel hole directly determines the sealing performance of the flow channel docking and the aerodynamic performance of the compressor. This is especially true for centrifugal compressors with horizontal split structures, which have even higher requirements for the contour matching of the flow channel hole.

[0003] In existing technologies, the air ducts of centrifugal compressors are mostly welded structures. The welding process is prone to deformation and dimensional deviations, resulting in a significant discrepancy between the actual contour of the air duct flow channel and the theoretical design dimensions, making it impossible to form a standardized and precise flow channel contour. Regarding the machining of the flow channel holes in the shell, the traditional method typically involves directly drilling holes in the shell according to the theoretical design dimensions of the air duct flow channel. Then, the contour of the shell hole is manually compared and repeatedly ground with the actual contour of the air duct flow channel to achieve proper alignment.

[0004] However, this traditional processing method has many drawbacks: on the one hand, manual grinding relies on the operator's experience, making it difficult to control the processing precision. This can easily lead to problems such as excessive gaps between flow channels and insufficient surface fit, affecting the operational stability of the centrifugal compressor. On the other hand, after rough cutting, multiple manual trial fittings and grindings are required, which is cumbersome, has extremely low processing efficiency, and the consistency of manual processing is poor, making it difficult to meet the process requirements of mass production. At the same time, manual grinding cannot accurately match the actual curved surface contour of the air duct flow channel, which can easily lead to damage to the aerodynamic performance of the flow channel and reduce the working efficiency of the centrifugal compressor. Summary of the Invention

[0005] In view of this, this application provides a method for machining flow channel holes that can automatically and accurately machine shell openings according to the actual contour of the air duct flow channel and achieve high-precision and smooth connection of the flow channel.

[0006] To achieve the above objectives, this application mainly provides the following technical solutions: This application provides a method for machining flow channel holes in a centrifugal compressor housing, the centrifugal compressor housing comprising a casing and a fan casing, the method comprising: Based on the theoretical design dimensions of the air duct channel, a rough cut hole is made at a preset position where the shell and the air duct meet to form a rough cut hole; The welded air duct is pre-assembled and positioned with the shell having its rough cut holes completed; The actual contour of the air duct is scanned and measured to obtain the contour surface data of the air duct. Process the contour surface data to generate extended surface data of the air duct flow channel surface facing the direction of the rough cutting hole of the housing. Automatically cut and grind the rough cutting hole of the housing according to the extended surface data.

[0007] Optionally, the rough cutting and opening at the preset position where the housing is对接 with the air duct according to the theoretical design dimensions of the air duct flow channel to form a rough cutting hole includes: Place the housing on the numerical control cutting workbench, and position and clamp the housing through a tooling fixture to ensure that the housing has no displacement during the processing. According to the theoretical design dimensions of the air duct flow channel, input the rough cutting contour parameters into the numerical control cutting system supporting the numerical control cutting workbench, and reserve a finishing allowance of 8 mm to 15 mm in the rough cutting contour parameters. Start the cutting equipment of the numerical control cutting workbench, and perform rough cutting and opening on the housing according to the cutting trajectory preset in the numerical control system to form the rough cutting hole.

[0008] Optionally, the finishing allowance is adjusted according to the wall thickness of the housing. The greater the wall thickness of the housing, the greater the value of the corresponding finishing allowance.

[0009] Optionally, the pre-assembly positioning of the welded air duct and the housing that has completed rough cutting and opening includes: Pre-assemble the welded air duct and the housing that has completed rough cutting and opening through an air duct tooling positioning frame to achieve relative positioning between the two.

[0010] Optionally, the scanning and measuring of the actual contour of the air duct flow channel to collect the contour surface data of the air duct flow channel includes: Integrate a measuring probe on the spindle of the numerical control machining center. Place the pre-assembled and positioned housing and air duct as a whole on the workbench of the numerical control machining center and position and clamp them. The numerical control machining center is adapted to the machining datum of the housing that has completed rough cutting and opening. According to the theoretical surface contour of the air duct flow channel, plan the scanning path for the inner wall of the air duct flow channel. Start the numerical control machining center. The spindle drives the measuring probe to extend into the air duct from one side of the housing through the rough cutting hole, and scan and measure the actual contour of the inner wall of the air duct flow channel according to the scanning path to collect the contour surface data of the air duct flow channel.

[0011] Optionally, the scanning path is a spiral scanning path or a grid scanning path, and the scanning point spacing of the scanning path is set to 0.5 mm to 2 mm.

[0012] Optionally, the scanning point spacing is adjusted according to the curvature of the inner wall surface of the air duct channel. The greater the curvature of the inner wall surface of the air duct channel, the smaller the corresponding value of the scanning point spacing.

[0013] Optionally, processing the contour surface data to generate extended surface data of the air duct flow channel surface facing the direction of the coarse-cut hole in the housing includes: The contour surface data is transmitted to a matching industrial computer to construct a three-dimensional point cloud data model of the actual contour of the air duct flow channel. The three-dimensional point cloud data model is imported into point cloud processing software, and the three-dimensional point cloud data model is preprocessed by noise reduction, simplification and hole filling. A three-dimensional curved surface model that matches the actual contour of the air duct flow channel is then fitted and generated. Based on the three-dimensional curved surface model, and in accordance with the aerodynamic design requirements of the centrifugal compressor flow channel, the three-dimensional curved surface model is naturally extended towards the direction of the coarse cut hole in the shell, extending to the inner wall of the coarse cut hole in the shell, thereby generating the extended curved surface model of the air duct flow channel surface and obtaining the corresponding extended curved surface data. The extended surface data is imported into the programming software of the CNC machining center. The extended surface data is converted into G-code machining trajectory data that the CNC machining center can recognize through the CAM automatic programming function, and the G-code machining trajectory data is saved to the CNC system of the CNC machining center.

[0014] Optionally, the automated cutting and grinding of the rough-cut hole in the housing based on the extended surface data includes: Replace the measuring probe on the spindle of the CNC machining center with a cutting tool, and calibrate the parameters of the cutting tool according to the G-code machining trajectory data; Start the CNC machining center and use the cutting tool to perform layered rough milling on the rough hole of the housing to remove the finishing allowance of the rough hole; Replace the finishing tool to perform finish milling on the hole wall after rough milling, so that the curved surface of the hole wall fits the extended curved surface data; The rough-cut hole is automatically cut and ground by using a grinding head to grind the hole wall and hole opening after precision milling.

[0015] Optionally, the process of automatically cutting and grinding the rough holes in the housing also includes online inspection and rework steps: After any of the rough milling, finish milling or grinding processes is completed, the actuator of the CNC machining center is replaced with the measuring probe to scan and detect the contour of the machined hole wall and obtain the actual machining contour data. The actual machining contour data is compared with the extended surface data to determine whether the machining error is within the preset allowable range; If the machining error exceeds the preset allowable range, the CNC machining center automatically adjusts the machining trajectory according to the error difference and performs supplementary machining on the hole wall until the machining error meets the preset allowable range.

[0016] By employing the above technical solution, this application has at least the following beneficial effects: The flow channel hole processing method provided in this application can directly complete the automated processing of the flow channel hole of the shell based on the actual contour of the welded air duct flow channel, eliminating the need for repeated manual comparison and grinding. This effectively improves the processing accuracy and efficiency of the flow channel hole of the shell, ensuring that the final flow channel hole on the shell closely matches the actual contour of the air duct flow channel, reducing the flow channel docking gap, improving the sealing of the assembly between the shell and the air duct, and enhancing the aerodynamic performance of the overall flow channel, thereby ensuring the stability and efficiency of the centrifugal compressor operation. Attached Figure Description

[0017] Figure 1 This is a flowchart of a flow channel hole processing method according to an optional embodiment of this application. Detailed Implementation

[0018] The present application will be described in detail below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present application can be combined with each other.

[0019] This embodiment provides a method for machining flow channel holes, see [link to relevant documentation]. Figure 1 As shown, the method includes: Step S101: Based on the theoretical design dimensions of the air duct flow channel, make a rough cut hole at the preset position where the shell and the air duct meet to form a rough cut hole.

[0020] The flow channel hole machining method provided in this application embodiment can be applied to fields such as centrifugal compressor manufacturing, specifically to the machining of flow channel holes in centrifugal compressor housings, which include a casing and a fan duct. When machining the flow channel holes in the centrifugal compressor housing, firstly, according to the theoretical design dimensions of the fan duct flow channel, a rough cut is made at a preset position where the casing and fan duct meet, forming a rough cut hole. Here, the rough cut hole provides operating space for subsequent scanning measurement and finishing, and reserves a set finishing allowance to ensure that the finally machined flow channel hole can match the actual contour of the fan duct flow channel with high precision.

[0021] Step S102: Pre-assemble and position the welded air duct with the shell with the rough cut holes.

[0022] In this embodiment, the welded air duct and the shell with the rough cut holes are pre-assembled and positioned according to the actual assembly relationship, so that the air duct and the shell maintain a stable relative position, providing an accurate assembly state for subsequent scanning measurement.

[0023] Step S103: Scan and measure the actual contour of the air duct flow channel to collect the contour surface data of the air duct flow channel.

[0024] In this embodiment, the actual contour of the pre-assembled and positioned air duct is fully scanned and measured. The actual contour surface data of the air duct is obtained through measurement, providing accurate original basis for subsequent data processing.

[0025] Step S104: Process the contour surface data to generate extended surface data of the air duct flow channel surface facing the direction of the coarse cut hole in the shell.

[0026] In this embodiment, the collected air duct flow channel contour surface data is processed, and the surface of the air duct flow channel is extended toward the direction of the rough cutting hole of the shell to generate extended surface data that can be used to guide the fine machining of the shell.

[0027] Step S105: Based on the extended surface data, perform automated cutting and grinding on the roughing holes of the housing.

[0028] In this embodiment, the rough-cut holes on the shell are automatically cut and ground according to the generated extended surface data, so that the final shell flow channel holes are precisely matched with the actual contour of the air duct flow channel, ensuring the accuracy and sealing of the flow channel connection.

[0029] By applying the technical solution of this embodiment, the automated processing of the flow channel hole in the shell can be completed directly based on the actual contour of the welded air duct flow channel, eliminating the need for repeated manual comparison and grinding. This effectively improves the processing accuracy and efficiency of the flow channel hole in the shell, ensuring that the final flow channel hole on the shell closely matches the actual contour of the air duct flow channel, reducing the flow channel docking gap, improving the sealing of the assembly between the shell and the air duct, and enhancing the aerodynamic performance of the overall flow channel. This, in turn, ensures the stability and efficiency of the centrifugal compressor operation.

[0030] Furthermore, as a refinement and extension of the specific implementation of the above embodiments, and to fully illustrate the specific implementation process of this embodiment, another method for processing flow channel holes is provided, the method comprising: Step S201: Place the housing on the CNC cutting platform and use tooling fixtures to position and clamp the housing so that the housing does not move during the processing.

[0031] In this embodiment, the housing can be lifted to the CNC cutting workbench by a traveling crane first, and then the housing is horizontally and vertically positioned and clamped by use of tooling fixtures to ensure that there is no displacement of the housing during the processing, and the positioning error is controlled within ±0.5 mm.

[0032] Step S202: According to the theoretical design dimensions of the air duct flow channel, input the rough cutting profile parameters into the CNC cutting system supporting the CNC cutting workbench, and reserve a finishing allowance of 8 mm to 15 mm in the rough cutting profile parameters.

[0033] In this embodiment, only the basic hole pattern is cut out, and there is no need for precise docking with the air duct flow channel. Among them, the finishing allowance is adjusted according to the wall thickness of the housing. The larger the wall thickness of the housing, the larger the corresponding finishing allowance value.

[0034] Step S203: Start the cutting equipment of the CNC cutting workbench, and perform rough cutting on the housing according to the cutting trajectory preset in the CNC system to form a rough cut hole.

[0035] In this embodiment, the corresponding cutting equipment can be selected according to the wall thickness of the housing. Among them, for medium-thick wall structures with a wall thickness of the housing not greater than 40 mm, a CNC plasma cutting machine is used for cutting, and for thick wall structures with a wall thickness of the housing greater than 40 mm, a CNC flame cutting machine is used for cutting.

[0036] Step S204: Pre-assemble the welded air duct and the housing that has completed rough cutting through the air duct tooling positioning frame to achieve relative positioning between the two.

[0037] In this embodiment, first pre-assemble and position the welded air duct and the housing through the air duct tooling positioning frame to ensure that the relative position between the air duct and the housing is consistent with the actual assembly state, and control the positioning error within ±0.3 mm. Then, use a dial indicator to detect the coaxiality of the air duct and the housing that have completed pre-assembly positioning.

[0038] Step S205: Integrate a measuring probe on the spindle of the CNC machining center, place the pre-assembled and positioned housing and air duct as a whole on the workbench of the CNC machining center and position and clamp them. The CNC machining center is adapted to the machining datum of the housing that has completed rough cutting.

[0039] In this embodiment, the CNC machining center is an independent device, distinct from the aforementioned CNC cutting platform, and includes, but is not limited to, CNC gantry machining centers and floor-mounted boring and milling machining centers. The CNC machining center is compatible with the machining datum of the shell after rough cutting and hole opening, ensuring that the shell's positional accuracy remains consistent after being transferred from the CNC cutting platform to the CNC machining center, using the same positioning datum used in the rough cutting process. The measuring probe can be a contact-type coordinate measuring machine probe or a non-contact laser scanning probe. In this embodiment, a non-contact laser scanning probe is used and is paired with the CNC machining center's probe system. The measuring probe can be integrated onto the spindle of the CNC machining center via a probe extension rod. The length of the extension rod is customized according to the depth of the air duct channel, and the specific length is not limited. In practical applications, the probe calibrator is first placed on the working platform of the CNC machining center, and the calibration program is started to calibrate the accuracy of the measuring probe. After calibration, the calibration parameters are saved to ensure that the measurement data has no systematic errors. Then, the welded air duct and the rough-cut shell are pre-assembled. The relative positions of the two are fixed by the air duct tooling positioning frame. The coaxiality and parallelism of the air duct and the shell are checked by dial indicator, and the various accuracies are adjusted to meet the unit assembly requirements.

[0040] Step S206: Based on the theoretical surface profile of the air duct, plan the scanning path for the inner wall of the air duct.

[0041] In this embodiment, a spiral or grid-type scanning path is planned in the CNC system of the CNC machining center based on the theoretical surface contour of the air duct. This embodiment uses a grid-type scanning path, with the scanning point spacing set to 0.5mm to 2mm. The scanning point spacing is adjusted according to the curvature of the inner wall surface of the air duct; the greater the curvature of the inner wall surface of the air duct, the smaller the corresponding scanning point spacing value, ensuring the integrity of the contour acquisition.

[0042] Step S207: Start the CNC machining center, and use the spindle to drive the measuring probe to extend into the air duct from one side of the housing through the roughing hole. Scan the actual contour of the inner wall of the air duct flow channel according to the scanning path, and collect the contour surface data of the air duct flow channel.

[0043] In this embodiment, during the scanning process, the moving speed of the measuring probe is controlled between 50 mm / min and 150 mm / min to avoid data distortion due to excessive movement. If welding protrusions or weld beads exist in the air duct flow channel, they must be lightly ground down to preserve the actual formed contour, removing only sharp protrusions to prevent damage to the measuring probe.

[0044] Step S208: Transmit the contour surface data to the supporting industrial computer to construct a three-dimensional point cloud data model that forms the actual contour of the air duct flow channel.

[0045] In this embodiment, the contour surface data is transmitted in real time to the supporting industrial computer through the CNC system of the CNC machining center, and stored in IGES / STEP surface data format to form a three-dimensional point cloud data model of the actual contour of the air duct flow channel.

[0046] Step S209: Import the 3D point cloud data model into the point cloud processing software, perform noise reduction, simplification and hole filling preprocessing on the 3D point cloud data model, and fit to generate a 3D curved surface model that matches the actual contour of the air duct flow channel.

[0047] In this embodiment, Geomagic Wrap point cloud processing software can be used as the point cloud processing software. The acquired 3D point cloud data of the air duct flow channel is imported into the point cloud processing software, and noise reduction, simplification, and hole filling operations are performed to remove invalid data points caused by measurement vibration and iron filings obscuring the data, and to fill in missing data points in the flow channel contour, ensuring the integrity and accuracy of the point cloud data. Then, the surface fitting function of the point cloud processing software is used to perform surface fitting on the preprocessed point cloud data to generate a 3D surface model that perfectly matches the actual contour of the air duct flow channel, controlling the fitting error within ±0.02mm.

[0048] Step S210: Based on the three-dimensional curved surface model, and in accordance with the aerodynamic design requirements of the centrifugal compressor flow channel, the three-dimensional curved surface model is naturally extended towards the direction of the coarse cut hole in the shell, extending to the inner wall of the coarse cut hole in the shell, to generate the extended curved surface model of the air duct flow channel surface, and obtain the corresponding extended curved surface data.

[0049] In this embodiment, based on the fitted three-dimensional surface model, the air duct flow channel is naturally extended in the direction of the coarse cut hole in the shell according to the aerodynamic design requirements of the centrifugal compressor flow channel, so that the extended surface reaches the inner wall of the coarse cut hole in the shell, thereby generating the extended surface model of the air duct flow channel surface and obtaining the corresponding extended surface data.

[0050] Step S211: Import the extended surface data into the programming software of the CNC machining center, convert the extended surface data into G-code machining trajectory data that can be recognized by the CNC machining center through the CAM automatic programming function, and save the G-code machining trajectory data to the CNC system of the CNC machining center.

[0051] In this embodiment, the obtained extended surface data is imported into the programming software of the CNC machining center. The CAM automatic programming function of the software is used to convert the extended surface data into G-code machining trajectory data that the CNC machining center can recognize and execute. The generated G-code machining trajectory data is then stored in the CNC system of the CNC machining center.

[0052] Step S212: Replace the measuring probe on the spindle of the CNC machining center with a cutting tool, and calibrate the cutting tool parameters according to the G-code machining trajectory data.

[0053] In this embodiment, the measuring probe installed on the spindle of the CNC machining center is removed and replaced with a cutting tool. The operating parameters and position parameters of the cutting tool are calibrated according to the G-code machining trajectory data stored in the CNC system to ensure the accuracy of the cutting tool machining path.

[0054] Step S213: Start the CNC machining center and use the cutting tool to perform layered rough milling on the rough holes of the housing to remove the finishing allowance of the rough holes.

[0055] In this embodiment, the CNC machining center is started and the corresponding machining program is run. The rough milling of the rough holes on the housing is performed in layers by the cutting tool, and all the finishing allowances reserved in advance for the rough holes are gradually removed.

[0056] Step S214: Change to a fine milling tool to perform fine milling on the hole wall after rough milling, so that the hole wall surface fits the extended surface data.

[0057] In this embodiment, the cutting tool on the CNC machining center is replaced with a precision machining tool to perform precision milling on the rough-cut hole wall, so that the curved surface formed by the hole wall is consistent with and completely fits the extended curved surface data.

[0058] Step S215: Use a grinding head to grind the wall and opening of the fine-milled hole to complete the automated cutting and grinding of the rough-cut hole.

[0059] In this embodiment, a grinding head is used to grind the surface of the hole wall and the hole opening position after precision milling, thereby improving the surface finish and dimensional accuracy of the hole wall and finally completing the entire automated cutting and grinding process of the rough hole of the shell.

[0060] Furthermore, the automated cutting and grinding process for the roughing holes in the housing also includes online inspection and rework steps: Step S216: After any of the rough milling, finish milling or grinding processes is completed, the actuator of the CNC machining center is replaced with a measuring probe to scan and detect the contour of the machined hole wall and obtain the actual machining contour data. Step S217: Compare the actual machining contour data with the extended surface data to determine whether the machining error is within the preset allowable range; Step S218: If the machining error exceeds the preset allowable range, the CNC machining center will automatically adjust the machining trajectory according to the error difference and perform supplementary machining on the hole wall until the machining error meets the preset allowable range.

[0061] In this embodiment, after any of the rough milling, finish milling, or grinding processes is completed, the actuator of the CNC machining center is replaced with a measuring probe to perform a complete scan and inspection of the machined hole wall contour and obtain the actual machining contour data. The actual machining contour data is compared with the extended surface data to determine whether the machining error is within the preset allowable range. The preset allowable range refers to the error interval set to ensure smooth connection between the housing flow channel hole and the air duct flow channel and to meet the assembly accuracy requirements of the centrifugal compressor, for example, ±0.05 mm. If the machining error exceeds the preset allowable range, the CNC machining center automatically adjusts the machining trajectory according to the error difference and performs supplementary machining on the hole wall until the machining error meets the preset allowable range. Through the above online detection and supplementary machining steps, the machining accuracy can be checked in real time and the machining deviation can be corrected in a timely manner, avoiding the final product from being unqualified due to the accumulation of errors, further improving the forming accuracy and surface quality of the housing flow channel hole, and ensuring a more accurate and reliable connection between the housing and the air duct flow channel.

[0062] The serial numbers in this application are for descriptive purposes only and do not represent the superiority or inferiority of any particular implementation scenario. The above disclosures are merely a few specific implementation scenarios of this application; however, this application is not limited thereto, and any variations conceived by those skilled in the art should fall within the protection scope of this application.

Claims

1. A flow passage hole processing method for processing a flow passage hole of a centrifugal compressor casing including a casing and a scroll, characterized by, The method includes: According to the theoretical design dimensions of the air duct flow channel, perform rough cutting and hole opening at a preset position where the housing is对接 with the air duct, forming a rough cut hole; Pre-assemble and position the welded air duct and the housing that has completed rough cutting and hole opening; Scan and measure the actual contour of the air duct flow channel, and collect the contour surface data of the air duct flow channel; Process the contour surface data to generate extended surface data of the air duct flow channel surface facing the direction of the rough cut hole of the housing; According to the extended surface data, perform automated cutting and grinding on the rough cut hole of the housing.

2. The method according to claim 1, characterized in that, The step of performing rough cutting and hole opening at a preset position where the housing is对接 with the air duct according to the theoretical design dimensions of the air duct flow channel, forming a rough cut hole, includes: Place the housing on a numerical control cutting workbench, and use a tooling fixture to position and clamp the housing to ensure that the housing has no displacement during the processing; According to the theoretical design dimensions of the air duct flow channel, input rough cut contour parameters into the numerical control cutting system supporting the numerical control cutting workbench, and reserve a finishing allowance of 8 mm to 15 mm in the rough cut contour parameters; Start the cutting equipment of the numerical control cutting workbench, and perform rough cutting and hole opening on the housing according to the cutting trajectory preset in the numerical control system, forming the rough cut hole.

3. The method according to claim 2, characterized in that, The finishing allowance is adjusted according to the wall thickness of the housing. The larger the wall thickness of the housing, the larger the corresponding value of the finishing allowance.

4. The method according to claim 1, characterized in that, The step of pre-assembling and positioning the welded air duct and the housing that has completed rough cutting and hole opening includes: Pre-assemble the welded air duct and the housing that has completed rough cutting and hole opening through an air duct tooling positioning frame to achieve relative positioning of the two.

5. The method according to claim 1, characterized in that, The step of scanning and measuring the actual contour of the air duct flow channel and collecting the contour surface data of the air duct flow channel includes: Integrate a measuring probe on the spindle of a numerical control machining center. Place the pre-assembled and positioned housing and air duct as a whole on the workbench of the numerical control machining center and position and clamp them. The numerical control machining center is adapted to the machining datum of the housing that has completed rough cutting and hole opening; According to the theoretical surface contour of the air duct flow channel, plan a scanning path for the inner wall of the air duct flow channel; Start the numerical control machining center. The spindle drives the measuring probe to extend into the air duct from one side of the housing through the rough cut hole, and scan and measure the actual contour of the inner wall of the air duct flow channel according to the scanning path to collect the contour surface data of the air duct flow channel.

6. The method according to claim 5, characterized in that, The scanning path is a spiral scanning path or a grid scanning path, and the scanning point spacing of the scanning path is set to 0.5 mm to 2 mm.

7. The method according to claim 6, characterized in that, The scanning point spacing is adjusted according to the inner wall surface curvature of the air duct flow channel. The larger the inner wall surface curvature of the air duct flow channel, the smaller the corresponding value of the scanning point spacing.

8. The method according to claim 5, characterized in that, The step of processing the contour surface data to generate extended surface data of the air duct flow channel surface facing the direction of the rough cut hole of the housing includes: The contour surface data is transmitted to a matching industrial computer to construct a three-dimensional point cloud data model of the actual contour of the air duct flow channel. The three-dimensional point cloud data model is imported into point cloud processing software, and the three-dimensional point cloud data model is preprocessed by noise reduction, simplification and hole filling. A three-dimensional curved surface model that matches the actual contour of the air duct flow channel is then fitted and generated. Based on the three-dimensional curved surface model, and in accordance with the aerodynamic design requirements of the centrifugal compressor flow channel, the three-dimensional curved surface model is naturally extended towards the direction of the coarse cut hole in the shell, extending to the inner wall of the coarse cut hole in the shell, thereby generating the extended curved surface model of the air duct flow channel surface and obtaining the corresponding extended curved surface data. The extended surface data is imported into the programming software of the CNC machining center. The extended surface data is converted into G-code machining trajectory data that the CNC machining center can recognize through the CAM automatic programming function, and the G-code machining trajectory data is saved to the CNC system of the CNC machining center.

9. The method according to claim 8, characterized in that, The automated cutting and grinding process for the rough-cut hole of the housing based on the extended surface data includes: Replace the measuring probe on the spindle of the CNC machining center with a cutting tool, and calibrate the parameters of the cutting tool according to the G-code machining trajectory data; Start the CNC machining center and use the cutting tool to perform layered rough milling on the rough hole of the housing to remove the finishing allowance of the rough hole; Replace the finishing tool to perform finish milling on the hole wall after rough milling, so that the curved surface of the hole wall fits the extended curved surface data; The rough-cut hole is automatically cut and ground by using a grinding head to grind the hole wall and hole opening after precision milling.

10. The method according to claim 9, characterized in that, The automated cutting and grinding process for the coarse holes in the housing also includes online inspection and rework steps. After any of the rough milling, finish milling or grinding processes is completed, the actuator of the CNC machining center is replaced with the measuring probe to scan and detect the contour of the machined hole wall and obtain the actual machining contour data. The actual machining contour data is compared with the extended surface data to determine whether the machining error is within the preset allowable range; If the machining error exceeds the preset allowable range, the CNC machining center automatically adjusts the machining trajectory according to the error difference and performs supplementary machining on the hole wall until the machining error meets the preset allowable range.

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