Method for controlling machining deformation of low-pressure guide vane inner casing

Abstract

The application discloses a low-pressure guide vane inner casing machining deformation control method, and belongs to the technical field of machining deformation control, which comprises the following steps: manufacturing a casing forging blank; coarsely opening a groove and a flow channel in the casing; performing stable treatment; cutting the casing into an upper casing and a lower casing; splitting and machining the upper casing and the lower casing; assembling and machining the upper casing and the lower casing after machining; splitting the upper casing and the lower casing, and machining non-equal-diameter holes respectively; assembling the upper casing and the lower casing, and machining precise stepped holes; cutting the left and right lines of the assembled casing to form four casings; performing final inspection after performing fluorescence treatment on the casing; and storing the cut casings in groups. The machining deformation of the low-pressure guide vane casing assembly machining process is controlled through the adjustment of process route optimization, machining content change in the process, grinding scheme improvement and inner hole end face groove cutting route optimization and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of aero-engine manufacturing research, in particular to a low-pressure guide vane inner casing machining deformation control method. BACKGROUND

[0002] The low-pressure guide vane casing is an important component of the compressor part, and the guide vane casing is designed as a split casing part composed of left and right half rings and upper and lower two sections. The part is circumferentially distributed with 40 precise holes, the part is an outer ring full-face tapered thin-wall flow passage part, the thinnest part is only 1.8 mm; the end surface is uniformly distributed with 6 coaxial non-equal-diameter deep long through holes, the left side is φ4(+0.04, +0.025), the right side is φ4(+0.012, 0), and the depth is 15.2; the part is axially uniformly distributed with 40 through holes, the end surface is uniformly distributed with 6 through holes and 20 threaded holes, and the whole is a porous weak rigid structure; the part is axially composed of two non-uniform parts, and the axial precise length size and the precise limiting end surface groove size need to be machined after combination to ensure that the combination machining process has high requirements

[0003] In the process of machining the flow passage of the existing low-pressure guide vane casing, the flow passage removal allowance is large, the radial removal allowance is unilaterally up to 15.2 mm, and machining deformation is easily generated, which leads to many out-of-tolerance coaxialities of the inner hole and hole diameters, and cannot meet the design requirements. SUMMARY

[0004] The present application provides a low-pressure guide vane inner casing machining deformation control method to solve the technical problem that the low-pressure guide vane inner casing is prone to deformation during machining.

[0005] According to one aspect of the present application, a low-pressure guide vane inner casing machining deformation control method is provided, comprising the following steps:

[0006] S100, manufacturing of a casing forging blank;

[0007] S200, rough machining of the casing inner groove and flow passage;

[0008] S300, stable treatment;

[0009] S400, cutting the casing wire into upper and lower two part casings;

[0010] S500, split machining of the upper and lower two part casings;

[0011] S600, combination and installation of the machined upper and lower two part casings and combined machining;

[0012] S700, split of the upper and lower two part casings and machining of non-equal-diameter holes;

[0013] S800, combination and installation of the upper and lower two part casings and combined machining of precise stepped holes;

[0014] S900, cutting the left and right lines of the combined installed case to form four parts of the case;

[0015] S100, after the case is treated with fluorescence, final inspection is performed, and the cut case is grouped into a warehouse.

[0016] Optionally, the step S500 of splitting and processing the upper and lower two parts of the case comprises:

[0017] S510, finishing the end face of the case to ensure the surface reference and combination requirements;

[0018] S520, splitting and finishing the inner groove and axial precision size of the case;

[0019] S530, splitting and processing the positioning precision connection pre-hole.

[0020] Optionally, the step S600 of combining and installing the processed upper and lower two parts of the case and performing combined processing comprises:

[0021] S610, combining the two parts of the case by using precision connection bolts;

[0022] S620, combined finishing of the inner hole to ensure coaxiality and inner hole roundness;

[0023] S630, electric spark grooving;

[0024] S640, processing of the flow channel, precision connection hole and threaded hole.

[0025] Optionally, in the step of roughing the inner groove and flow channel of the case, an installation edge for clamping in subsequent processes is reserved.

[0026] Optionally, in the step of roughing the inner groove and flow channel of the case, the case is clamped and fixed in a way of one side supporting and the other side pressing.

[0027] Optionally, in the step of finishing the end face of the case to ensure the surface reference and combination requirements, grinding is used, the whole surface is supported and pressed through the installation edge during grinding, one surface is ground to the position first, then the other surface is ground to the final size by using the ground surface as the support.

[0028] Optionally, in the step of splitting and finishing the inner groove and axial precision size of the case, since the part is in an inclined state after roughing, considering that one-time clamping and processing of the inner groove will cause pressing deformation, the two precision grooves are processed in two processes, while ensuring that the surface reference and hole reference are consistent when finding the reference, after processing the second precision groove, the first precision groove processed in the previous process is measured to verify whether the precision groove after processing is deformed.

[0029] Optionally, in the step of verifying whether there is deformation after processing, the qualified size of the precision groove is ΦA(+0.052, 0) and ΦB(0, +0.057).

[0030] To sum up, the present application includes at least one of the following beneficial technical effects:

[0031] 1. The process of opening rough the inner groove and the runner part before linear cutting increases the risk of deformation, and compared with cutting the casing into two parts and then roughing and finishing the inner groove and the runner, the casing is a whole before linear cutting, which is more stable. At this time, opening rough the inner groove and the runner can further reduce the risk of deformation during processing.

[0032] 2. Considering that one-time clamping processing of the inner groove will cause compression deformation, processing the two precision grooves in two processes can improve the processing accuracy and reduce the risk of casing deformation.

[0033] 3. By adjusting the process route, changing the processing content in the process, improving the grinding scheme, and optimizing the cutting route of the inner hole end face groove, the low-pressure guide vane casing combined machining process deformation is controlled.

[0034] In addition to the purposes, features and advantages described above, the present application has other purposes, features and advantages. The present application will be further described below with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0035] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application, illustrate the preferred embodiments of the application and aid in explaining the application. In the drawings:

[0036] Figure 1 A schematic diagram of the low-pressure guide vane inner casing machining deformation control method of the present application;

[0037] Figure 2 A clamping schematic diagram of the inner groove and runner roughing step of the casing of the present application;

[0038] Figure 3 A grinding clamping schematic diagram of the finish machining of the casing end face of the present application;

[0039] Figure 4 A schematic diagram of the inner groove machining size of the present application. DETAILED DESCRIPTION

[0040] The embodiments of the present application will be described in detail below with reference to the accompanying drawings, but the present application can be implemented in various different ways as defined and covered below.

[0041] The application will be further described below in conjunction with the accompanying drawings. Figures 1-4 The application will be further described below in conjunction with the accompanying drawings.

[0042] The application discloses a low-pressure guide vane inner casing machining deformation control method.

[0043] Referring to Figure 1 The low-pressure guide vane inner casing machining deformation control method comprises the following steps:

[0044] S100, manufacturing of a casing forging blank;

[0045] S200, roughing of the inner groove and flow passage of the casing;

[0046] S300, stable treatment;

[0047] S400, cutting the casing into an upper casing and a lower casing;

[0048] S500, machining of the upper casing and the lower casing;

[0049] S600, combination and machining of the machined upper casing and lower casing;

[0050] S700, splitting of the upper casing and the lower casing, and machining of non-equal-diameter holes;

[0051] S800, combination and machining of the upper casing and the lower casing, and machining of precise stepped holes;

[0052] S900, cutting of the combined casing into four casings;

[0053] S100, final inspection of the casing after fluorescent treatment, and grouping of the cut casings into a warehouse.

[0054] In step S100, the manufacturing of the low-pressure guide vane inner casing forging blank usually adopts a forging process, in which a high-temperature alloy material is heated to an appropriate temperature and then forged into a shape in a die.

[0055] In step S200, the roughing of the inner groove and flow passage of the casing is performed by removing most of the excess material from the forging blank under the condition of good overall stability, while reserving mounting edges for clamping in subsequent processes. This process can significantly reduce the cutting allowance in subsequent finishing, thereby reducing the risk of machining deformation and ensuring the final machining precision and part quality.

[0056] In the prior art, the casing line-cutting part is divided into two parts, the thin ring thickness is only 7.4mm, and the soft jaw clamping machining is adopted in the numerical control machining. Due to the radial clamping force of the soft jaw, the flatness of the thin ring part after machining is about 0.1mm, and the subsequent grinding needs to grind the front and back surfaces reciprocally to grind the part flat. At the same time, the material of the part is high-quality deformed superalloy, which cannot be magnetized, and only relies on the positioning magnets at the inner and outer six positions for limiting on the rotary table grinder. A large amount of grinding heat is generated during grinding of the part, which is easy to cause the part to be adsorbed by the grinding wheel and separated from the workbench and burned and deformed. In the embodiment, the mounting edge for clamping in the subsequent process is reserved in the steps of roughing the inner groove and flow channel of the casing. This operation can ensure that the part can be firmly and accurately fixed during subsequent finishing process, avoid deformation caused by unstable clamping, and improve machining precision and overall quality.

[0057] Reference Figure 2 Specifically, in the steps of roughing the inner groove and flow channel of the casing, the casing is clamped and fixed in a way that one side is supported and the other side is pressed. During machining, one side of the casing is tightly supported on the fixed device, and the other side is subjected to appropriate pressure by the pressing device, so that the part remains stable during machining. The effect of this fixing method is to effectively prevent the part from shifting or deforming due to unstable clamping during machining, thereby ensuring the roughing machining accuracy of the inner groove and flow channel and improving the machining quality of the part.

[0058] In the step S300 of stabilizing treatment, the casing is usually treated by heat treatment process to eliminate the internal stress and organizational stress generated in the previous machining, thereby improving the dimensional stability of the part. The role of this step is to reduce the risk of deformation in subsequent machining, and to ensure the stability of the shape and size of the part during subsequent finishing process, thereby improving the machining precision and overall product quality.

[0059] In the step S400, the casing is accurately divided into upper and lower two parts by the wire cutting process. This process is usually carried out by a high-speed electric spark wire cutting machine tool to ensure the accuracy and surface quality of cutting. The role of this step is to divide the whole casing into two parts for subsequent machining, so that the complex inner groove, flow channel and other precise structures can be machined more flexibly and accurately on the divided parts, thereby improving the machining efficiency and precision.

[0060] The step S500 includes:

[0061] S510, finishing the end face of the casing to ensure the surface reference and combination requirements; by finishing the end face of the casing, the flatness and reference accuracy of the end face are ensured by using high-precision machining equipment, so that it reaches the tolerance range required by the design. The role of this step is to provide an accurate surface reference for the subsequent part combination, to ensure that each part can be closely fitted when combined, to ensure the combination accuracy of the whole part and the final machining quality.

[0062] Referring to Figure 3 , the finishing process of the end face of the casing ensures the face reference and the assembly requirements. In this step, grinding is used for processing. When grinding, the whole face is supported and pressed through the installation edge. During processing, the face with better flatness is used for support first, and the other face is ground to the position. Then, the ground face is used for support, and the other face is processed to the final size. The role of this step is to ensure the flatness and size accuracy of the end face, provide an accurate reference surface, and thus meet the accuracy requirements of the subsequent assembly of the part, ensuring the quality and stability of the overall assembly.

[0063] S520, split the inner groove and axial precision size of the finishing casing; by splitting the casing that has been divided, and finishing the inner groove and axial precision size, using special fixtures and processing equipment to ensure that the size of each part meets the design requirements. The role of this step is to ensure the high precision of the inner groove and axial size of the casing, so that each part can be accurately aligned in the subsequent assembly and overall assembly, thereby improving the functionality and assembly quality of the part.

[0064] S530, split processing positioning precision connection pre-hole. After splitting the casing, the positioning precision connection pre-hole is processed, and high-precision processing equipment is used to ensure that the size and position accuracy of these pre-holes meet the design requirements. The role of this step is to provide an accurate positioning basis for the accurate assembly and fixation of subsequent parts, ensuring that each part can be correctly aligned and connected during assembly, thereby ensuring the overall functionality and structural stability of the casing.

[0065] Referring to Figure 4 , in the step of splitting the inner groove and axial precision size of the finishing casing, considering that the one-time clamping and processing of the inner groove will cause compression deformation, the two precision grooves are processed in two processes, while ensuring that the face reference and hole reference are consistent during alignment. After processing the second precision groove, the first precision groove processed in the previous process is measured to verify whether the processed precision groove has deformation. By processing the two precision grooves in two processes, compression deformation caused by one-time clamping and processing is avoided, ensuring the accuracy of the inner groove processing. At the same time, by ensuring the consistency of the face reference and hole reference during processing, and measuring the first precision groove after processing the second precision groove, the processing deformation can be effectively controlled, ensuring that the size accuracy and shape of the final part meet the design requirements, thereby ensuring the overall quality and performance of the casing. In the step of verifying whether there is deformation after processing, the qualified size of the precision groove is ΦA(+0.052,0), ΦB(0, +0.057).

[0066] Step S600 includes:

[0067] S610, two-part casing is combined by using precision connecting bolts; the two-part casing after splitting is combined by using precision connecting bolts, so that the accurate alignment and close connection of each part are ensured during the bolt fastening process. The role of this step is to ensure that the combined casing has high precision coaxiality and structural integrity, laying a stable foundation for subsequent processing steps, so as to ensure the function and quality of the final part.

[0068] S620, combined finishing inner hole, ensure coaxiality and inner hole roundness; the combined casing is finished by inner hole, high-precision processing equipment and process means are used to ensure that the coaxiality and roundness of the inner hole reach the tolerance range required by the design. The role of this step is to ensure the geometric accuracy of the inner hole through accurate machining, so as to ensure that the part can work stably in actual operation, and avoid performance degradation or structural failure caused by coaxiality or roundness error.

[0069] S630, electric spark grooving; the combined casing is grooved by electric spark machining process, and the required groove shape and size are accurately cut by using electric spark discharge principle. The role of this step is to provide precise groove structure for the functional requirements of the part, so as to ensure that the shape and size of the groove meet the design standard, thereby meeting the specific functional requirements of the part in assembly and use.

[0070] S640, flow channel, precision connecting hole and thread hole processing. The role of this step is to ensure the fluid dynamic performance, structural connection strength and fastening effect of the part in the final assembly by accurately processing these key features, so as to ensure the overall performance and functionality of the casing.

[0071] The present application controls the machining deformation of the low-pressure guide vane casing and improves the machining precision by the following methods: first, by optimizing the process route, roughening the inner groove and flow channel before stable processing, removing most of the excess amount and reserving the mounting edge for subsequent clamping, reducing the deformation risk during finishing; second, adjusting the processing content in the process, such as using whole surface support and step-by-step processing method during end face grinding, to ensure the flatness and reference accuracy of the end face; at the same time, in the cutting of inner hole and end face groove, through step-by-step finishing and multiple calibration and measurement, the compression deformation caused by one-time clamping is avoided; finally, by improving the grinding scheme and the processing technology of precision connecting hole, the coaxiality and position accuracy during combined machining are ensured, so as to effectively control the deformation problem in the machining of the casing, improve the overall machining precision, and ensure the smooth delivery and high quality completion of the part.

[0072] The above only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A low-pressure guide vane inner casing machining deformation control method, characterized in that, comprising the following steps: S100, manufacturing of a casing forging blank; S200, roughing of an inner groove and a flow passage of the casing; S300, stable treatment; S400, cutting of the casing into an upper and a lower two-part casing; S500, split machining of the upper and lower two-part casing; S600, combined installation and combined machining of the processed upper and lower two-part casing; S700, split of the upper and lower two-part casing, and machining of non-equal-diameter holes respectively; S800, combined installation and combined machining of the upper and lower two-part casing, and machining of a precise stepped hole; S900, cutting of the combined installed casing into a left and a right four-part casing; S100, final inspection after fluorescent treatment of the casing, and grouping of the cut casings into a warehouse; the split machining step S500 of the upper and lower two-part casing comprises: S510, finish machining of a casing end face to ensure a surface reference and combined requirements; S520, split finish machining of an inner groove and an axial precise dimension of the casing; S530, split machining of a positioning precise connection pre-hole; in the split finish machining step of the inner groove and the axial precise dimension of the casing, since the part is in an inclined state after roughing, considering that one-time clamping and machining of the inner groove in place will cause compression deformation, the two precise grooves are machined in two processes, while ensuring that the surface reference and the hole reference are consistent when the positioning is performed, and after machining of the second precise groove, the first precise groove machined in the previous process is measured to verify whether the precise groove after machining has deformation.

2. The low-pressure guide vane inner casing machining deformation control method according to claim 1, characterized in that, the combined installation and combined machining step S600 of the processed upper and lower two-part casing comprises: S610, combination of the upper and lower two-part casing by using precise connection bolts; S620, combined finish machining of an inner hole to ensure coaxiality and inner hole roundness; S630, electric spark grooving; S640, machining of a flow passage, a precise connection hole and a threaded hole.

3. The low-pressure guide vane inner casing machining deformation control method according to claim 2, characterized in that: in the roughing step of the inner groove and the flow passage of the casing, an installation edge for subsequent process clamping is reserved.

4. The low-pressure guide vane inner casing machining deformation control method according to claim 3, characterized in that: in the roughing step of the inner groove and the flow passage of the casing, the casing is clamped and fixed in a way that one side is supported and the other side is compressed.

5. The low-pressure guide vane inner casing machining deformation control method according to claim 1, characterized in that: in the finish machining step of the casing end face to ensure the surface reference and the combined requirements, grinding is adopted, the whole surface is supported during grinding and is compressed through the installation edge, and during machining, the surface with better flatness is supported first, the other surface is ground to place, then the ground surface is supported for machining the other surface to the final size.

6. The low-pressure guide vane inner casing machining deformation control method according to claim 5, characterized in that: in the step of verifying whether there is deformation after machining, the qualified size of the precise groove is ΦA (+0.052, 0) and ΦB (0, +0.057). ​

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