Machining clamp and machining method for guide inner support

Abstract

The invention provides a machining method of a guide inner support, which comprises the following steps: during rough machining, firstly machining a large end face, then machining a part inner hole and a part outer circle, and finally machining a small end face and removing the allowance of the part inner hole; when the large end face is roughly machined, the small end face is used as a rough positioning reference; when the inner hole and the outer circle of the part are roughly machined, the large end face of the part is used as a rough positioning reference; when the small end face is roughly machined and the inner hole allowance of the part is removed, the reverse side of the large mounting edge serves as a supporting face. Furthermore, an electric spark machining clamp is arranged, the electrode machining state is changed, and inclined machining in the prior art is changed into vertical machining. And by improving the processing procedure, the parallelism of the reverse side of the mounting edge relative to the reference surface I is directly guaranteed instead of being indirectly guaranteed in the original procedure. According to the invention, the qualification rate of parallelism and the product quality are improved; meanwhile, in the improved scheme, no newly-added procedure is needed, the machining process is not affected, and the machining duration is effectively controlled.

Description

Technical Field

[0001] This invention relates to the field of machining technology, and more specifically, to a machining fixture and machining method with an inner guide support. Background Technology

[0002] The first-stage guide support is a component of the engine turbine section. The first stage guide refers to the gas turbine's first-stage guide, and the first-stage guide support is a supporting component within it. This inner support is a ring-shaped part made of a high-temperature alloy. One end has a large-diameter mounting edge, and the other end has a smaller-diameter mounting edge. The smaller mounting edge, along with other components, is fixed to the rotor assembly for a sealing function. The side of the large mounting edge facing the smaller mounting edge is called the reverse side of the large mounting edge. This reverse side mates with the inner end face of the gas turbine's first-stage guide. There is a parallelism requirement between the reverse side of the large mounting edge and the end face of the smaller mounting edge. Figure 1 The diagram shows a partial view of an inner support, where reference 'I' represents the end face of the small mounting edge. The outer circle of the inner support has a stepped structure, consisting of a large mounting edge 1, outer circle one 2, outer circle two 3, and small mounting edge 4. There is also a stepped structure between outer circle one 2 and outer circle two 3. The outer diameters of the large mounting edge 1, outer circle one 2, outer circle two 3, and small mounting edge 4 gradually decrease. Two end face grooves are located on outer circle one 2 near the large mounting edge 1, and air film holes 5 are evenly distributed on outer circle two 3 near the small mounting edge 4 for gas passage in the guide. The large mounting edge 1 is also stepped, with the smaller outer diameter portion located on the outer side.

[0003] As described above, a guide inner support generally has a gradually decreasing diameter structure, with one end being thicker and the other thinner, while the blank of a guide inner support has a structure with one end larger and the other smaller. In this invention, the larger end refers to the larger end of the workpiece before it is processed into a product, and the larger end face refers to the end face of the larger end; the smaller end refers to the smaller end of the workpiece before it is processed into a product, and the smaller end face refers to the end face of the smaller end.

[0004] During the machining process of a single-guide inner support, technicians discovered the following technical problems with the existing machining methods for single-guide inner supports: 1. For example Figure 1 As shown, during rough machining of a part, the smaller end face of the other end is machined first, using the larger end face as a support surface; then, the larger end face, outer diameter, and inner hole are machined using the smaller end face as a support surface, as... Figure 2 As shown, the machining allowance for the large end face is L1 (e.g., L1 = 9.3 mm), and the minimum wall thickness of the support part is L2 (e.g., L2 = 3.45 mm). During the cutting process, the axial cutting force continuously acts on the workpiece, causing deformation of the small end face that serves as the support surface, making it difficult to guarantee the axial dimension. If the rough machining dimensions of the part are not up to standard, re-clamping and rework will result in a significant waste of manpower and resources, affecting the production schedule.

[0005] 2. Air film holes are evenly distributed on the outer circumference near the small mounting edge. These air film holes are oblique holes tilted at a 75°29′ angle relative to the workpiece axis, machined using electrical discharge machining (EDM) with an electrode diameter of Ф1.2 and a spindle yaw angle of 14°31′. After machining, the hole diameter was found to be out of tolerance. Measurement with a mandrel revealed that the hole was conical. This out-of-tolerance diameter was due to the use of only one set of parameters during EDM, failing to consider the allowance and integrity of the air film hole inlet and outlet, resulting in unstable machining quality.

[0006] For example, patent application CN116372288A, entitled "A Radial Film Hole Processing Device," describes a device with multiple processing modules that can move and extend along multiple degrees of freedom within the internal space of the part to be processed. This invention can process multiple or groups of radial film holes at once using electrical discharge machining (EDM), improving processing efficiency and product quality while significantly reducing processing time. Although it can accelerate processing efficiency, the aforementioned technical problems still exist.

[0007] 3. The parallelism of the reverse side of the mounting edge of the part relative to the I datum plane is out of tolerance, and the machining pass rate at this point is only 4.5%. Analysis reveals the following two main reasons for this: (1) The inner support of the guide is generally made of GH625 high temperature alloy material. This material still has good tensile properties at temperatures below 980℃. In order to ensure the sealing of the parts and the rotor, after the inner hole is removed by machining, the honeycomb is vacuum brazed in the inner hole of the inner support. However, the vacuum brazing temperature is 1040±10℃. After welding, the parts will inevitably have a small warping deformation in the outer circumferential direction, which will lead to an increase in the flatness of the small end face of the parts. Subsequently, the large mounting edge reverse side and the outer circle are precision machined to the design size by coloring and pressing the small end face, as shown in the figure. After this process, the small end face will be precision machined. Since the small end face with a larger flatness is used as the support surface when precision machining the large mounting edge reverse side, the parallelism of the large mounting edge reverse side relative to the small end face exceeds the tolerance after precision machining of the small end face.

[0008] When performing subsequent machining processes to the design dimensions for the radial dimensions of the large mounting edge and the outer side of the large mounting edge, as shown in the figure, the small end face is usually used as the support surface for machining. This process cannot correct the parallelism deviation caused by the above, and the parallelism of the reverse side of the large mounting edge relative to the I datum plane cannot be guaranteed.

[0009] (2) When performing the end face groove machining process on the outer circle one, as shown in the figure, the color support is used to press the large end face to machine the two end face grooves. This is a large allowance cutting. At the same time, the cutting force is large when the groove tool is machined. After the part is machined, there is stress release, which further aggravates the deformation of the part and affects the parallelism of the large mounting edge reverse side relative to the I datum plane.

[0010] In summary, existing technologies for machining inner support components have problems such as deformation after rough machining, out-of-tolerance issues with the air mold holes, and out-of-tolerance issues with the precision parallelism of the mounting edge on the reverse side. Summary of the Invention

[0011] The technical problem to be solved by the present invention is to provide a processing method for an inner support of a guide, which solves the problems of deformation after rough machining of the parts, out-of-tolerance of the air mold holes of the parts, and out-of-tolerance of the precision parallelism of the reverse side of the mounting edge of the parts, thereby ensuring the quality of the inner support of the guide.

[0012] A machining method for a single-guide inner support involves first machining the large end face, then machining the inner hole and outer diameter of the part, and finally machining the small end face and removing the allowance from the inner hole. During rough machining of the large end face, the small end face is used as the rough positioning datum. During rough machining of the inner hole and outer diameter of the part, the large end face is used as the rough positioning datum. During rough machining of the small end face and removal of the allowance from the inner hole, the reverse side of the large mounting edge is used as the support surface.

[0013] This feature addresses the technical problem raised in point 1 of the background technology.

[0014] Remove the excess material from the inner hole and outer circle of the part first, and rough machine the small end face with the large end face as the reference surface. Avoid cutting the part for a long time, so that the axial cutting force can continue to act on the part and cause deformation. Also avoid the part deformation affecting the pass rate of axial dimensions, and at the same time ensure the parallelism of the I surface.

[0015] Furthermore, when performing electrical discharge machining on film holes, a fixture is used to tilt the part so that the film holes are perpendicular to the machining plane; and the diameter of the electrode guide sleeve is reduced.

[0016] This feature addresses the technical problem raised in point 2 of the background technology.

[0017] By changing the electrode machining state from the existing tilting machining to vertical machining, the error caused by the weight of the electrode itself during tilting machining is reduced, ensuring the machining quality of the pneumatic mold hole of the part. At the same time, the clamping, alignment and tool setting time is reduced, improving machining efficiency and machining stability.

[0018] Furthermore, when performing the finishing of outer circle one, large mounting edge and outer circle two, the large end face is first finished by coloring and pressing the small end face, and a machining allowance is left in the axial direction; then, the outer side of the large mounting edge, the radial side of the large mounting edge, the reverse side of the large mounting edge and outer circle one are finished to the design dimensions using the small end face as the support surface.

[0019] This feature addresses the technical problems raised in points (1) and (3) of the background art.

[0020] First, the large end face is precision machined, leaving a machining allowance in the axial direction to facilitate subsequent machining corrections. Subsequent machining includes precision machining of the outer side of the large mounting edge, the radial side of the large mounting edge, the reverse side of the large mounting edge, and the outer circle to the design dimensions. This helps ensure the flatness of datum I.

[0021] Furthermore, during the machining of the end face groove, the large end face is used as the reference surface for support. This effectively reduces the deformation caused by machining the end face groove and helps to ensure the flatness of the reference I. The machining process of the end face groove is located before the machining processes of the outer side of the large mounting edge, the radial side of the large mounting edge, the reverse side of the large mounting edge, and the outer circle.

[0022] This feature addresses the technical problem raised in point 3, paragraph (2) of the background art.

[0023] Through the above-mentioned scheme modification and processing verification, the deformation of the mounting edge in the rough machining process of the part was controlled, the EDM air film hole processing was qualified, and the pass rate of the reverse side of the large mounting edge of the part was increased to 95%.

[0024] Furthermore, the fixture includes a base plate, a vertical plate, a shaft, a positioning plate, a pressure plate, and a guide sleeve. The base plate is used to mount on an EDM high-speed drilling machine. The base plate includes a mounting surface and a supporting surface. The mounting surface is fixed to the EDM high-speed drilling machine, and the supporting surface forms an angle α with the mounting surface, causing the workpiece mounted on the fixture to tilt at an angle α, which is equal to the tilt angle of the film-forming hole relative to the small end face. The vertical plate is vertically fixed to the supporting surface. The shaft passes through the vertical plate and is movably connected to it. One end of the shaft is fixed with the positioning plate. A pressure plate is provided on the positioning plate, and the workpiece is pressed and fixed by the pressure plate and the positioning plate. A guide sleeve with a guide hole is fixed on one side of the positioning plate. During drilling, the guide hole and the center line of the film-forming hole are on the same straight line. The machining electrode is placed in the guide sleeve to machine the film-forming hole.

[0025] This invention designs a special fixture for EDM drilling, adding a guide hole at the entrance of the pneumatic die hole on the part, changing the electrode machining state from inclined machining to vertical machining, reducing the error caused by the weight of the electrode itself during inclined machining, ensuring the machining quality of the pneumatic die hole on the part, while reducing the clamping, alignment and tool setting time, improving machining efficiency and machining stability.

[0026] Furthermore, the fixture also includes a pin, the upright plate has a pin hole that matches the pin, the positioning plate has a positioning hole, the number of positioning holes is equal to the number of air film holes, and the size of the positioning hole is equal to the size of the pin hole; when the workpiece is installed on the positioning plate, the pin hole, positioning hole, and air film hole are aligned, and the pin passes through the pin hole into the positioning hole.

[0027] In this invention, during processing, the pin passes through the pin hole into the positioning hole, which limits the turntable, i.e., limits the workpiece. After processing one air film hole, the pin is pulled out, the positioning plate is rotated, and one hole position is rotated to process the adjacent air film hole. The pin is then inserted into the pin hole and the adjacent positioning hole. In this invention, there is only one pin hole and one pin, the number of positioning holes is equal to the number of air film holes, and the graduation of the positioning holes is equal to the circumferential graduation value of the air film holes.

[0028] Furthermore, the guide sleeve is mounted on the upright plate via a mounting base. The guide sleeve is L-shaped, with a guide hole at one end and the other end fixed to the mounting base. The mounting base includes a base body and a rotating plate. The base body is fixed to the upright plate and has a positioning groove. One end of the rotating plate and the guide sleeve can be placed in the positioning groove. The widths of the positioning groove, the rotating plate, and the guide sleeve are equal. The guide sleeve is movably mounted in the positioning groove, and the width of the guide sleeve is greater than its thickness, allowing one end of the guide sleeve to rotate within the positioning groove. When the rotating plate and one end of the guide sleeve are placed in the positioning groove, one end of the rotating plate contacts the guide sleeve, restricting its rotation. The rotating plate is movably mounted in the positioning groove, allowing it to rotate out of the positioning groove, thereby releasing the restriction on the rotation of the guide sleeve.

[0029] Furthermore, a limiting structure is provided at the end of the shaft that is not fixed to the turntable. The limiting structure includes a bushing, a washer, and a nut arranged sequentially in the axial direction of the shaft. The upright plate is fitted onto the bushing, and the bushing and the upright plate are fixed by fasteners. Tightening the nut presses the washer, bushing, upright plate, and positioning disc together to prevent the positioning disc from rotating.

[0030] Furthermore, the fixture also includes an angular pin, which is perpendicular to the positioning disk and passes through a connecting hole on the small end face of an inner support to limit the position of the part relative to the positioning disk.

[0031] The inner end face of the inner support also has a connecting hole for fixing the inner support to other components.

[0032] The present invention has the following beneficial effects: 1. Improve the roughing process by removing the excess material from the inner hole and outer diameter of the part before machining the small end face and removing the excess material from the inner hole. This avoids prolonged cutting of the part, where the axial cutting force acts continuously, causing part deformation. This prevents part deformation from affecting the axial dimension pass rate and the flatness of the small end face.

[0033] 2. During the finishing process, the large end face is finished first, leaving a machining allowance in the axial direction. When the flatness exceeds the tolerance due to deformation of the workpiece caused by vacuum brazing sealing honeycomb, machining end face groove, etc., the subsequent finishing of the outer side of the large mounting edge, the radial side of the large mounting edge, the reverse side of the large mounting edge, and the outer circle can be corrected according to the test results, thus improving the pass rate of flatness.

[0034] 3. When opening the end face groove, the large end face is supported by the whole surface support. On the one hand, the flatness of the datum I is guaranteed, and on the other hand, the whole surface support can effectively reduce the deformation caused by machining the end face groove. Attached Figure Description

[0035] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a partial view of an inner support of a guide; Figure 2 This is a schematic diagram of process A in the existing technology; Figure 3 A schematic diagram of process B in the existing technology; Figure 4 This is a schematic diagram of an internal support structure. Figure 5 This is a schematic diagram of process C in the existing technology; Figure 6 This is a schematic diagram of process D in the existing technology; Figure 7 A schematic diagram of the existing technology process F; Figure 8 A schematic diagram of the existing technology G process; Figure 9 This is a schematic diagram of process A of the present invention; Figure 10 This is a schematic diagram illustrating the rough machining of the inner hole and outer diameter of the part according to the present invention; Figure 11 This is a schematic diagram of process B of the present invention; Figure 12 This is a front view of the fixture of the present invention; Figure 13 This is a right view of the fixture of the present invention; Figure 14 This is a left view of the clamp of the present invention; Figure 15 This is a perspective view of the fixture of the present invention.

[0036] The serial numbers are: 1-Large mounting edge, 1a-Reverse side of large mounting edge, 1b-Radial side of large mounting edge, 1c-Outer side of large mounting edge, 2-Outer circle one, 3-Outer circle two, 4-Small mounting edge, 4a-Hole on small mounting edge, 5-Air film hole, 6-Sealing honeycomb, 7a-Colored support surface one, 7b-Pressure surface one, 8-End face groove, 9-Base plate, 10-Firming plate, 11-Vertical plate, 12-Positioning plate, 12a-Positioning hole, 13-Shaft, 14-Bushing, 15-Pin, 16-Pressure plate, 17-Angular pin, 18-Seat body, 19-Rotating plate, 20-Shaft pin, 21-Guide sleeve, 21a-Guide hole, 22-Cylindrical pin, 23-Nut, 24-Washer, 25-Rectangular head screw, 26-Part, 27-U-groove. Detailed Implementation

[0037] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but the present invention can be implemented in many different ways as defined and covered by the claims.

[0038] Example 1 Existing technology involves the following steps when processing an inner guide support: Process A: Using the large end face as a support surface, machine the small end face of the other end, such as... Figure 2 As shown; Process B: Using the small end face as a support surface, machine the large end face, outer circle, and inner hole, such as... Figure 3 As shown; Process C: Vacuum brazing to seal the honeycomb 6 inside the workpiece's inner hole, such as... Figure 5 As shown; Process D: Using a colored support and clamping method on the small end face, the large end face, the reverse side of the large mounting edge 1a, and the outer circle 2 are precision machined to the design dimensions, such as... Figure 6 As shown, number 7a is the colored support surface, and number 7b is the corresponding pressing surface; as Figure 6 As shown, the large end face is Figure 6 The right end of the position shown; Process E: Finishing of the small end face; Process F: Using a coloring and pressing method on the large end face, process the two end face grooves 8, such as... Figure 7 As shown; Process G: Using the small end face as the support surface, precision machine the radial dimension 1b of the large mounting edge and the outer dimension 1c of the large mounting edge to the design dimensions, such as... Figure 8 As shown; H process: Electrical discharge machining of air film holes.

[0039] Appendix of the present invention Figure 2 , 3 The bold black lines in numbers 6, 8, 9, 10, and 11 represent the outlines formed by the processing of the parts. Figure 3 , 10The dashed lines in 11 represent the outline before processing.

[0040] The above process is part of the entire process of machining the inner support of the guide, but process AH is arranged according to the order of the part machining process.

[0041] In process B, the small end face is used as the support surface, the machining allowance of the large end face is 9.3mm, and the minimum wall thickness of the support part is 3.45mm. During the cutting process, the axial cutting force is continuously applied to the workpiece, causing the small end face, which serves as the support surface, to deform, making it difficult to guarantee the axial dimension.

[0042] In process C, the inner support of the guide is generally made of GH625 high-temperature alloy material. This material still has good tensile properties at temperatures up to 980℃. In order to ensure the sealing of the parts and the rotor, after the inner hole is removed by machining, the honeycomb 8 is vacuum brazed in the inner hole of the inner support. However, the vacuum brazing temperature is 1040±10℃. After welding, the parts will inevitably have a small warping deformation in the outer circumferential direction, which will lead to an increase in the flatness of the small end face of the parts.

[0043] During process D, due to deformation caused by processes B and C, the large end face, the reverse side of the large mounting edge, and the outer circle were precision machined to the design dimensions, resulting in dimensional deviations.

[0044] In process F, two end face grooves are machined. This is a large allowance cutting process. At the same time, the cutting force is large during grooving. After the part is machined, there is stress release, which further aggravates the deformation of the part and affects the parallelism of the reverse side of the large mounting edge relative to the I datum plane.

[0045] During process G, only the radial dimension and outer side of the large mounting edge are finished to the design dimensions. No machining is performed on the reverse side of the large mounting edge. Furthermore, since no machining allowance was left during process D, the dimensional deviations caused by processes B, C, and F cannot be corrected, and the parallelism of the reverse side of the large mounting edge relative to the I datum plane cannot be guaranteed.

[0046] During process H, such as Figure 4 The shown film gas hole is an oblique hole tilted at an angle of 75°29′ relative to the workpiece axis. It was machined using electrical discharge machining (EDM) with a machining electrode diameter of Ф1.2 and a spindle yaw angle of 14°31′. After machining, the hole diameter was found to be out of tolerance. Measurement with a mandrel revealed that the hole was conical. The out-of-tolerance hole diameter was due to the use of only one set of parameters during EDM, which did not take into account the allowance integrity of the hole at the inlet and outlet, resulting in unstable machining quality.

[0047] The above processes A, B, and C cause workpiece deformation, and the axial dimensions are difficult to guarantee. During process D, directly finishing the large end face, the reverse side of the large mounting edge, and the outer diameter to the design dimensions results in dimensional deviations. Process F further exacerbates the deformation. In process D, no axial allowance was left, and after completing process G, the parallelism of the reverse side of the large mounting edge relative to the I datum plane cannot be guaranteed. The EDM machining of the film-forming holes in process H further reduces product quality.

[0048] To address the technical problems existing in the AH process described above, this embodiment provides a machining method for an inner support, as detailed below: The machining method for an inner support guide involves, during rough machining, first machining the large end face, then machining the inner hole and outer diameter of the part, and finally machining the small end face and removing the excess material from the inner hole; for example... Figure 9 As shown, when rough machining the large end face, the small end face is used as the rough positioning reference; as Figure 10 As shown, when rough machining the inner hole and outer diameter of a part, the large end face of the part is used as the rough positioning datum; as Figure 11 When rough machining the small end face and removing the allowance of the inner hole of the part, the reverse side of the large mounting edge is used as the support surface.

[0049] This invention first improves processes A and B to avoid part deformation caused by prolonged use of the small end face as a support surface and large machining allowance.

[0050] When machining film holes using electrical discharge machining (EDM), the part is tilted using a fixture to ensure the film hole is perpendicular to the machining plane; the diameter of the electrode guide sleeve is also reduced. The EDM parameters are optimized and adjusted by setting three different sets of machining parameters, with different process parameters determined based on the varying machining allowances at different hole depths.

[0051] The D process is improved by only finishing the large end face. First, the small end face is finished using a coloring and pressing method (same as the original D process), with axial machining allowance. During the D process, the reverse side 1a of the large mounting edge and the outer circle 2 are not finished. The finishing of the reverse side 1a of the large mounting edge and the outer circle 2 is performed in the G process.

[0052] Improve process G by using the small end face after finishing as the support surface, and finish the large mounting edge reverse side 1a and outer circle 12 that were not machined in the original process D, as well as the outer side 1c and radial side 1b of the large mounting edge in the original process G, to the design dimensions.

[0053] This invention improves processes D and G, and leaves a machining allowance in the axial direction during process D, so that the parallelism of the mounting edge reverse side 1a relative to the I reference surface is directly guaranteed by process G, thereby improving the pass rate of parallelism.

[0054] The F process was improved by using the large end face as the reference surface for the entire surface support during the end face groove machining, which effectively reduced the deformation caused by the machining of the end face groove and helped to ensure the flatness of the reference surface I.

[0055] Example 2 A machining fixture for a single-guide inner support is used in the machining of the air film hole 5 in the single-guide inner support machining method of Embodiment 1, such as... Figure 12 and Figure 13 As shown, the fixture includes a base plate 9, a vertical plate 11, a shaft 13, a positioning plate 12, a pressure plate 16, and a guide sleeve 21. The base plate 9 is used to mount on an EDM high-speed drilling machine. The base plate 9 includes a mounting surface and a supporting surface. The mounting surface is fixed to the EDM high-speed drilling machine. The vertical plate 11 is vertically mounted on the supporting surface of the base plate 9. The supporting surface and the mounting surface form an angle α, so that the workpiece mounted on the fixture is tilted at an angle α, which is equal to the tilt angle of the air film hole 5 relative to the small end face. The shaft 13 passes through the vertical plate 11 and is movably connected to the vertical plate 11. One end of the shaft is fixed to the positioning plate 12. The positioning plate 12 is provided with a pressure plate 16, and the workpiece is pressed and fixed by the pressure plate 16 and the positioning plate. A guide sleeve 21 with a guide hole 21a is fixed on one side of the positioning plate 12. During drilling, the guide hole 21a and the center line of the air film hole 5 are on the same straight line. The machining electrode is placed in the guide sleeve 21 to process the air film hole 5.

[0056] When mounting part 26 onto the fixture, the large end face of part 26 contacts the positioning plate 12, and fasteners are used to press part 26 onto the positioning plate 12 via the pressure plate 16. Due to angle α, the fixture is mounted at an angle on the high-speed EDM drilling machine, but the air film hole 5 is perpendicular to the machining plane, that is, perpendicular to the mounting surface of the base plate 9, as shown. Figure 14 The angle is 90°. This embodiment is designed because the air film hole 5 is an oblique hole, which is inconvenient to process. This fixture can make the air film hole 5 perpendicular to the processing plane, reduce the error caused by the weight of the electrode itself when it is tilted during processing, ensure the processing quality of the air film hole of part 26, and at the same time reduce the clamping, alignment and tool setting time, improve processing efficiency and processing stability.

[0057] like Figure 13As shown, the fixture also includes a pin 15. The upright plate 11 has a pin hole that matches the pin 15. The positioning plate 12 has positioning holes 12a, the number of which is equal to the number of air film holes 5. The size of the positioning holes 12a is equal to the size of the pin holes. When the workpiece is mounted on the positioning plate 12, the pin holes and positioning holes 12a are aligned, and the pin 15 passes through the pin hole into the positioning hole 12a. The pin 15 passing through the pin hole into the positioning hole 12a can limit the rotation of the turntable, that is, limit the workpiece. After machining one air film hole 5, the pin 15 is pulled out, the positioning plate 12 is rotated, and one hole position is rotated to machine the adjacent air film hole 5. The pin 15 is then inserted into the pin hole and the adjacent positioning hole 12a. In this invention, there is only one pin hole and one pin 15. The number of positioning holes 12a is equal to the number of air film holes 5. The indexing of the positioning holes 12a is equal to the circumferential indexing value of the air film holes 5. Rotating by one indexing value, one hole is machined. The air film holes 5 on the part 26 are machined sequentially. In this invention, the guide sleeve 21 is stationary. Only the positioning disk 12 drives the part 26 to rotate and switch the air film holes 5 sequentially. The rotation of the positioning disk 12 is driven by the rotation of the shaft 13.

[0058] To facilitate the installation of the guide sleeve 21, the guide sleeve 21 is mounted on the upright plate 11 via a mounting base, such as... Figure 15 As shown, the guide sleeve 21 is L-shaped. One end of the L-shaped guide sleeve 21 has the guide hole 21a, and the other end is fixed to the mounting base. The guide sleeve 21 is rotatably connected to the mounting base. When installing the workpiece, the guide sleeve 21 is rotated so that the guide sleeve 21 does not interfere with the part 26.

[0059] The mounting base includes a base body 18 and a rotating plate 19. The base body 18 is fixed to the upright plate 11, and a positioning groove is formed on the base body 18. Figure 15 As shown, one end of the rotating plate 19 and the guide sleeve 21 can be placed in the positioning groove; the end of the guide sleeve 21 located in the positioning groove is square, and the widths of the positioning groove, the rotating plate 19, and the guide sleeve 21 are equal; the guide sleeve 21 is movably installed in the positioning groove, and the width of the guide sleeve 21 is greater than the thickness of the guide sleeve 21 so that one end of the guide sleeve 21 can rotate in the positioning groove; when one end of the rotating plate 19 and the guide sleeve 21 is placed in the positioning groove, one end of the rotating plate 19 contacts the guide sleeve 21 to restrict the rotation of the guide sleeve 21, and fasteners are used to fix the rotating plate 19 to the base 18; the rotating plate 19 is movably installed in the positioning groove so that the rotating plate 19 can rotate out of the positioning groove, thereby releasing the restriction on the rotation of the guide sleeve 21. In this embodiment, the rotating plate 19 is rotatably connected by a pivot pin 20; the rotating plate 19 has a U-shaped groove 27, and the bottom of the positioning groove has a screw hole. Fasteners (rectangular head screws 25 in this embodiment) are used to pass through the U-shaped groove 27 and engage with the screw hole at the bottom of the positioning groove to fix the rotating plate 19 to the base 18. Figure 15As shown, the seat 18 in this embodiment is also L-shaped. One side of the L-shaped seat 18 is used to fix it to the upright plate 11. In this embodiment, a cylindrical shape 22 is used to fix the seat to the upright plate 11. The other side is provided with a positioning groove, a rotating plate 19 and a guide sleeve 21.

[0060] like Figure 13 As shown, a limiting structure is provided at the end of the shaft 13 that is not fixed to the turntable. The limiting structure includes a bushing 14, a washer 24 and a nut 23 arranged sequentially in the axial direction of the shaft 13. In this embodiment, the washer 24 is an open washer. The upright plate 11 is fitted on the bushing 14. The bushing 14 and the upright plate 11 are fixed by fasteners. Tightening the nut 23 will axially press the washer 24, the bushing 14, the upright plate 11 and the positioning plate 12 together.

[0061] like Figure 15 As shown, the fixture also includes an angular pin 17, which is perpendicular to the positioning disk 12. The angular pin 17 passes through a connecting hole on the small end face of an inner support to position the part 26 relative to the positioning disk 12.

[0062] like Figure 13 As shown, the fixture is also equipped with stiffening plates 10 to serve as reinforcing ribs.

[0063] Example 3 A method of using the fixture, as described in Example 2, is as follows: Before processing, the fixture is placed horizontally on the high-speed EDM drilling machine. The part 26 is loaded into the fixture, and a hole on the small end face of the part is aligned with the angular pin 17 on the positioning plate 12, thus completing the positioning of the part on the positioning plate 12. After the part is positioned, the pressure plate 16 is used to press the part 26 onto the positioning plate 12, and fasteners are used to fix the pressure plate 16 to the positioning plate 12. In this embodiment, the positioning plate has four evenly distributed pressure plates 16.

[0064] After part 26 is positioned on the positioning plate 12, the guide sleeve 21 is rotated 90 degrees. At this time, the guide hole 21a of the guide sleeve 21 is aligned with one of the air film holes 5 on part 26. The pin 15 is inserted through the vertical plate 11 into the positioning hole on the positioning plate 12. Then, the machining electrode is moved into the guide sleeve 21 to complete the machining of the first air film hole. After machining one air film hole, the nut 23 is loosened and the pin 15 is pulled out. The positioning plate 12 is rotated by the rotating shaft 13, and the pin 15 is inserted into the adjacent positioning hole 12a. Part 26 is clamped on the positioning plate 12. When the shaft 13 rotates, part 26 and the positioning plate 12 rotate together. The number of positioning holes 12a on the positioning disk 12 is equal to the number of air film holes 5. The graduation of the positioning holes 12a is equal to the circumferential graduation of the air film holes 5. Each time the disk rotates to an adjacent positioning hole 12a, the adjacent air film hole 5 rotates to the guide sleeve 21. The guide sleeve 21 has a processing electrode, which can directly process the adjacent air film holes 5.

[0065] When clamping the part, unscrew the rectangular head screw 25 and rotate the rotating plate 19 out of the positioning slot. Rotate the guide sleeve 21 away from the positioning plate 12 to avoid interference between the guide sleeve 21 and the part 26 during installation. After the part 26 is clamped, rotate the guide sleeve 21 towards the positioning plate 12, rotate the rotating plate 19 into the positioning slot, and tighten it with the rectangular head screw 25 to complete the positioning of the guide sleeve 21.

[0066] After clamping the part 26 and installing the guide sleeve 21, the fixture of the present invention only needs to rotate the shaft 13 to switch the air film hole 5. The guide hole 21a positions and guides the electrode, making switching convenient and positioning good, thus improving the processing quality of the air film hole.

[0067] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of the present invention.

Claims

1. A machining fixture with an inner guide support, characterized in that, The fixture includes a base plate, a vertical plate, a shaft, a positioning plate, a pressure plate, and a guide sleeve. The base plate is used to mount on a high-speed EDM drilling machine. The base plate includes a mounting surface and a supporting surface. The mounting surface is fixed to the high-speed EDM drilling machine, and the supporting surface forms an angle α with the mounting surface, causing the workpiece mounted on the fixture to tilt at an angle α, which is equal to the tilt angle of the air film hole relative to the small end face. The vertical plate is vertically fixed to the supporting surface. The shaft passes through the vertical plate and is movably connected to it. One end of the shaft is fixed to the positioning plate. A pressure plate is provided on the positioning plate, and the workpiece is pressed and fixed by the pressure plate and the positioning plate. A guide sleeve with a guide hole is fixed on one side of the positioning plate. During drilling, the guide hole and the center line of the air film hole are on the same straight line. The machining electrode is placed in the guide sleeve to machine the air film hole.

2. The machining fixture for an inner guide support according to claim 1, characterized in that, The fixture also includes a pin, and the upright plate has a pin hole that matches the pin. The positioning plate has a positioning hole, the number of which is equal to the number of the air film holes, and the size of the positioning hole is equal to the size of the pin hole. When the workpiece is installed on the positioning plate, the pin hole, positioning hole, and air film hole are aligned, and the pin passes through the pin hole into the positioning hole.

3. The machining fixture for an inner guide support according to claim 2, characterized in that, The guide sleeve is mounted on the vertical plate via a mounting base. The guide sleeve is L-shaped, with a guide hole at one end and the other end fixed to the mounting base. The guide sleeve is rotatably connected to the mounting base. When installing a workpiece, the guide sleeve is rotated to prevent interference between the guide sleeve and the workpiece.

4. The machining fixture for an inner guide support according to claim 3, characterized in that, The mounting base includes a base body and a rotating plate. The base body is fixed to the upright plate. A positioning groove is formed on the base body, and one end of the rotating plate and the guide sleeve can be placed in the positioning groove. The widths of the positioning groove, the rotating plate, and the guide sleeve are equal. The guide sleeve is movably installed in the positioning groove, and the width of the guide sleeve is greater than the thickness of the guide sleeve so that one end of the guide sleeve can rotate in the positioning groove. When one end of the rotating plate and the guide sleeve is placed in the positioning groove, one end of the rotating plate contacts the guide sleeve, restricting the rotation of the guide sleeve. The rotating plate is movably installed in the positioning groove, allowing the rotating plate to rotate out of the positioning groove, thereby releasing the restriction on the rotation of the guide sleeve.

5. The machining fixture for an inner guide support according to claim 4, characterized in that, The end of the shaft that is not fixed to the turntable is provided with a limiting structure. The limiting structure includes a bushing, a washer, and a nut arranged sequentially in the axial direction of the shaft. The upright plate is fitted on the bushing, and the bushing and the upright plate are fixed by fasteners. Tightening the nut presses the washer, bushing, upright plate, and positioning plate together.

6. The machining fixture for an inner guide support according to claim 5, characterized in that, The fixture also includes an angular pin, which is perpendicular to the positioning disk. The angular pin passes through a connecting hole on the small end face of an inner support to limit the position of the part relative to the positioning disk.

7. A method for processing a single-guide inner support, characterized in that, The outer circle of the inner support is a stepped structure, consisting of a large mounting edge, outer circle one, outer circle two, and a small mounting edge. Two end face grooves are located on outer circle one near the large mounting edge, and air film holes are evenly distributed on outer circle two near the small mounting edge for gas to pass through the guide. The characteristic feature is that, when performing electrical discharge machining on the air film holes, the fixture described in any one of claims 1-6 is used to tilt the part so that the air film holes are perpendicular to the machining plane; and the diameter of the electrode guide sleeve is reduced.

8. The processing method of the inner support of the guide according to claim 7, characterized in that, During rough machining, the large end face is machined first, followed by the inner hole and outer diameter of the part, and finally the small end face and the excess material in the inner hole are removed. When rough machining the large end face, the small end face is used as the rough positioning datum. When rough machining the inner hole and outer diameter of the part, the large end face is used as the rough positioning datum. When rough machining the small end face and removing the excess material in the inner hole, the reverse side of the large mounting edge is used as the support surface.

9. The processing method of an inner support according to claim 8, characterized in that, When performing finishing of outer circle one, large mounting edge and outer circle two, first use the method of coloring and pressing the small end face to finish the large end face, and leave a machining allowance in the axial direction; then use the small end face as the support surface to finish the outer side of the large mounting edge, the radial side of the large mounting edge, the reverse side of the large mounting edge and outer circle one to the design dimensions.

10. The processing method of an inner support according to claim 9, characterized in that, When machining the end face groove, the large end face is used as the reference surface for the entire surface support.

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