A method for processing a radial type groove of a thin-walled annular part and a thin-walled annular part

Abstract

The present application belongs to the field of thin-walled annular part processing, and relates to a thin-walled annular part radial groove machining method and a thin-walled annular part. After rough milling and first-time semi-fine milling, the pressing plate is loosened and then re-pressed, so as to release the stress generated in the machining process, reduce the deformation of the part due to elastic recovery, thereby avoiding the deviation of the measured value and the actual machining value caused by deformation, avoiding size instability, and only processing the upper side wall during the second-time semi-fine milling, and then further processing through fine machining, respectively, first processing the upper side wall of the groove one by one, and then processing the lower side wall according to the actual thickness of each upper side wall, so that the upper and lower side walls of each groove can be independently fine machined according to the measured data of their respective positions, the error caused by the inconsistency of the high and low points of the part surface is compensated, the symmetry of all radial grooves relative to the upper and lower end faces of the part can meet the requirements, and the size and symmetry out-of-tolerance problems caused by one knife compensation machining are avoided.

Description

Technical Field

[0001] This invention belongs to the field of thin-walled annular parts processing, and relates to a processing method for radial grooves in thin-walled annular parts and thin-walled annular parts. Background Technology

[0002] A certain linkage ring is a thin-walled annular component. This part requires N grooves to be machined on its inner surface. See [reference needed]. Figure 1a and Figure 1b The groove height dimension H has a symmetry requirement of 0.1 and strict dimensional tolerances. After machining, the thickness of the part at the groove is only 3.5mm on one side, making it prone to deformation.

[0003] The conventional machining method involves two parts: rough milling and finish milling. Rough milling removes excess material, followed by finish milling to ensure the required dimensions and symmetry of the grooves. All grooves are machined using one tool offset for both rough and finish milling. However, this method has drawbacks: because the parts are thin-walled, deformation occurs during machining, causing deviations between measured and actual machined dimensions, resulting in dimensional errors. Furthermore, the surface of the part itself has high and low points, making it impossible to guarantee that the center points of the grooves are at the same height. Machining using the conventional method may lead to symmetry errors in some grooves. Therefore, the machining method needs to be improved to eliminate part deformation and to machine individual grooves individually to ensure the part's dimensional characteristics meet the requirements. Summary of the Invention

[0004] The purpose of this invention is to solve the problem that in the prior art, all grooves are rough and finish milled using one tool compensation each, which easily leads to dimensional and symmetry errors. This invention provides a method for machining radial grooves in thin-walled annular parts and a thin-walled annular part.

[0005] To achieve the above objectives, the present invention employs the following technical solution: A method for machining a radial groove in a thin-walled annular part includes the following steps: S1: The thin-walled annular part to be processed is clamped onto the tooling using a pressure plate; S2: Rough mill each radial groove on the thin-walled annular part to be machined; S3: Perform the first semi-finish milling on each radial groove; S4: After loosening the pressure plate, tighten it again to make the end face of the part runout within the preset range; S5: Perform a second semi-finish milling on the upper sidewalls of each radial groove; S6: Obtain the total thickness of the part, the actual thickness of the upper sidewall, and the height of each radial groove; determine the actual machining thickness of the upper sidewall; perform finishing machining on the upper sidewall based on the actual machining thickness of the upper sidewall; and complete the machining of the upper sidewall. S7: Based on the upper sidewall thickness after S6 machining, the total thickness of the part, the height of each radial groove, and the tool width, determine the actual machining thickness of the lower sidewall. Perform finishing machining on the lower sidewall according to the actual machining thickness to complete the machining of the lower sidewall.

[0006] A further improvement of the present invention is that: The actual machining thickness of the upper sidewall is calculated using the following formula: B1 = A1 - (AH) / 2 + D Where A1 is the actual measured thickness of the upper sidewall of the groove; A is the total thickness of the part; H is the height of the groove; and D is the point value corresponding to the machining allowance during the second semi-finish milling.

[0007] During the second semi-finish milling, the point value D corresponding to the machining allowance is calculated using the following formula: D = 0.5H - 0.5dC Where C is the machining allowance during the second semi-finish milling; d is the width of the milling cutter.

[0008] The actual machined thickness of the lower sidewall is calculated using the following formula: B2 = A1 - (AH) / 2 + D - 0.5d + E Where A1 is the actual measured thickness of the upper sidewall of the groove; A is the total thickness of the part; H is the height of the groove; D is the point value corresponding to the machining allowance during the second semi-finish milling; d is the width of the milling cutter; and E is the thickness allowance of the lower sidewall left after the first semi-finish milling.

[0009] In S2, when rough milling each radial groove, a layered milling method is adopted.

[0010] In S3, during the first semi-finish milling, a allowance of 0.25-0.3mm is reserved.

[0011] In S5, during the second semi-finish milling, the machining allowance is 0.1-0.15mm.

[0012] In step S4, after loosening the pressure plate, the pressure plate is tightened again so that the end face runout of the part is less than or equal to 0.02mm.

[0013] In step S7, after finishing the lower sidewall, the actual height of each groove is measured. If the height does not reach the pre-machined height of each radial groove, fine milling is performed by adjusting the tool compensation until the groove design height is reached.

[0014] A thin-walled annular part includes a plurality of grooves distributed on the inner sidewall of the thin-walled annular part, the grooves being obtained by the processing method described in this invention.

[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a method for machining radial grooves in thin-walled annular parts. After rough milling and the first semi-finish milling, the pressure plate is loosened and then tightened again to release the stress generated during machining, reduce the deformation of the part due to elastic recovery, and thus avoid deviations between the measured values ​​and the actual machining values ​​caused by deformation, thereby avoiding dimensional instability. In the second semi-finish milling, only the upper sidewall is machined. Then, through further finishing machining, the upper sidewalls of the groove are machined one by one, and then the corresponding lower sidewalls are machined according to the actual thickness of each upper sidewall. This allows the upper and lower sidewalls of each groove to be independently finished based on the measured data of their respective positions, compensating for the errors caused by the inconsistency of the high and low points on the surface of the part. This ensures that the symmetry of all radial grooves relative to the upper and lower end faces of the part meets the requirements, avoiding the dimensional and symmetry deviation problems caused by a single tool-compensated machining. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1a This is a schematic diagram of the groove of the part to be processed disclosed in an embodiment of the present invention; Figure 1b As disclosed in the embodiments of the present invention Figure 1a Sectional view along axis AA; Figure 2 This is a schematic diagram of the upper dimensions of the semi-finish milled groove disclosed in an embodiment of the present invention; Figure 3 This is a schematic diagram of the upper dimensions of the precision-milled groove disclosed in an embodiment of the present invention; Figure 4 This is a schematic diagram of the lower dimension of the precision-milled groove disclosed in an embodiment of the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0019] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0020] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0021] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0022] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0023] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0024] The present invention will now be described in further detail with reference to the accompanying drawings: This embodiment discloses a machining method for processing radial grooves in thin-walled annular parts, mainly involving rough milling, semi-finish milling, and finish machining, wherein: Rough milling: The main purpose is to remove most of the excess material, without pursuing final dimensional accuracy and surface quality. It usually uses a large depth of cut and feed rate, allowing for subsequent machining allowance. The surface of the machined part is relatively rough, and the dimensions are close to but do not meet the drawing requirements.

[0025] In this embodiment, each radial groove is milled in layers in step 2, machining the upper and lower parts of the groove separately. This quickly removes most of the material from the groove area, leaving the allowance required for subsequent semi-finish milling.

[0026] Semi-finish milling: A transitional stage between rough milling and finish milling. It further removes the excess material remaining after rough milling, bringing the part dimensions closer to the design values, while providing a uniform, smaller allowance for finish milling and improving surface quality. Semi-finish milling can be performed once or multiple times, with the aim of reducing cutting forces and controlling deformation during finish milling.

[0027] In this embodiment, two semi-finish milling operations were mainly performed: First semi-finish milling: Simultaneously machine the upper and lower sidewalls of the groove to further remove excess material and reserve a uniform finishing allowance for finishing.

[0028] Second semi-finish milling: After loosening and re-tightening the pressure plate, only the upper sidewall is semi-finish milled again. This step is specifically designed to eliminate the effects of deformation and establish a more accurate reference for the finishing of the upper sidewall.

[0029] Finishing: The final machining stage, ensuring the part meets the dimensional tolerances, geometric tolerances, and surface roughness requirements specified in the drawings. This involves small depths of cut and high cutting speeds, typically requiring compensation or adjustment based on measured dimensions.

[0030] In this embodiment, the upper sidewall and the lower sidewall are respectively finished: Finish machining of the upper sidewall: Measure the total thickness of the part and the actual thickness of the upper sidewall at each groove location. Calculate the machining dimensions independently for each groove using a CNC program to complete the final machining of the upper sidewall. Finish the lower sidewall: Based on the thickness of the already machined upper sidewall, the total thickness of the part, the height of the groove, and the width of the tool, calculate the final machining dimensions of the lower sidewall for each groove and complete the machining.

[0031] Symmetry: The degree of symmetry between the center plane of the radial groove and the upper and lower end faces of the thin-walled annular part.

[0032] See Figures 2 to 4 This invention discloses a method for machining radial grooves on thin-walled annular parts. Specifically, it is a method for machining multiple radial grooves on thin-walled annular parts to reduce the deformation of the parts and to ensure that the symmetry dimensions of each groove are qualified when machining multiple grooves simultaneously. The method includes the following steps: Step 1: Set up a coordinate system, clamp the thin-walled annular part to be processed onto the fixture using a pressure plate, and determine the zero point for part processing.

[0033] Step 2: Select the tool setting point. During rough milling, use layer milling to rough mill the upper and lower parts of the groove separately. Then, perform the first semi-finish milling on the groove at point N, leaving sufficient allowance.

[0034] Furthermore, in this step, a margin of 0.25-0.3mm is reserved.

[0035] Furthermore, in this step, a T-slot cutter with a diameter of 105mm and a thickness of 12mm is selected for rough milling, with a depth of cut of 0.5mm per pass; the feed rate is 40mm / min, and the spindle speed is 500r / min.

[0036] Furthermore, in this step, during the first semi-finish milling, a T-slot cutter is selected with a diameter of 105mm, a thickness of 12mm, and a rotation speed of 500r / min.

[0037] Step 3: After semi-finish milling, loosen the pressure plate and re-tighten it to reduce stress deformation during part machining. Before machining, check that the end face runout of the part is within the required range. See [link to relevant documentation]. Figure 2 After tightening the pressure plate on the upper side of the groove at point N, a second semi-finish milling is performed with a allowance of C.

[0038] Specifically, when releasing the pressure plate, create a gap of 0.5 to 1 mm between the pressure plate and the end face of the part, and maintain this state for 10 to 30 seconds to fully release the processing stress.

[0039] Furthermore, in this step, during the second semi-finish milling, a T-slot cutter is selected with a diameter of 105mm and a thickness of 12mm.

[0040] Furthermore, in this step, a dial indicator is used to measure the runout of the upper surface of the part. The part is rotated one revolution, and the runout should be less than or equal to 0.02 mm.

[0041] Furthermore, in this step, the allowance for C is 0.1-0.15mm.

[0042] Step 4: Finish machining of the upper side of the groove at point N: Obtain the total thickness of the part, the actual thickness of the upper sidewall, and the height of each radial groove. Determine the actual machining thickness of the upper sidewall. Based on the actual machining thickness of the upper sidewall, finish machining the lower sidewall to complete the machining of the lower sidewall. Specifically, it includes: Before machining, fill the measured thickness value of the part into the CNC program variable value parameter, for example: A=25 (measured value before machining). Starting from the first groove, measure the thickness of the upper side of N grooves in sequence and input it into the CNC program variable value parameter, for example: A1~AN. Machining can only begin after the input is completed. The program uses the following formula to calculate and ensure the thickness of the upper side of the groove: B1 = A1 - (AH) / 2 + D like Figure 3 As shown, B1 is the final machined dimension of the upper side thickness, A1 is the actual measured dimension of the upper side thickness, A is the total thickness of the part, H is the height dimension of the groove, and D is the point value when machining the upper side with the allowance C, i.e., D=0.5H-0.5dC, where d is the width of the milling cutter.

[0043] Step 5: Finish machining the lower side of the groove at point N: Based on the thickness of the upper sidewall after machining in step 4, the total thickness of the part, the height of each radial groove, and the width of the tool, determine the actual machining thickness of the lower sidewall. Finish machining the lower sidewall according to the actual machining thickness to complete the machining of the lower sidewall.

[0044] Before machining, the measured thickness value of the part is entered into the CNC program variable value parameter, for example: A=25 (measured value before machining). Starting from the first groove, the thickness of the upper side of N grooves is measured sequentially and entered into the CNC program variable value parameter, for example: A1~AN. Machining can only begin after the input is completed. The program uses the following formula to ensure the thickness of the bottom side of the groove: B2 = A1 - (AH) / 2 + D - 0.5d + E like Figure 4 As shown, B2 is the final machined dimension of the lower side thickness, and E is the allowance for the lower side thickness after the first semi-finish milling. After machining, the actual value of the groove height H is measured, and then the tool compensation is adjusted to the final groove height while ensuring that the symmetry is qualified.

[0045] In the processing method disclosed in this embodiment, the pressure plate is loosened and then tightened again after semi-finish milling to reduce stress deformation during the part processing. Pre-processing checks ensure the end face runout of the part is within the required range, which can reduce part deformation during processing and avoid errors between actual processed values ​​and measured values.

[0046] Furthermore, in the processing method disclosed in this embodiment, by adding variable values, the actual value of each groove is measured before processing, and the actual allowance of each groove is calculated. During processing, processing can be carried out for different allowances of each groove to ensure that all dimensional characteristics are qualified.

[0047] This embodiment also discloses a thin-walled annular part, such as Figure 1a and Figure 1b As shown, the thin-walled annular part is a linkage ring for an aero-engine. The part is made of 40CrNiMoA alloy steel, with an outer diameter of 280mm, an inner diameter of 260mm, and a total thickness of A=25mm. There are 12 radial grooves evenly distributed along the circumference on the inner side of the part. The design height of each groove is H=8mm, and the symmetry requirement is 0.1mm. After the grooves are machined, the remaining wall thickness on one side of the part at the bottom of the groove is only 3.5mm.

[0048] The thin-walled annular part disclosed in this embodiment is obtained by rough milling, first semi-finish milling, stress relief by loosening and tightening pressure plates, second semi-finish milling, top sidewall fine milling with measurement and compensation for each groove, bottom sidewall fine milling with compensation for each groove, and finally tool finishing to the design height.

[0049] This machining method releases stress generated during machining by loosening and re-tightening the pressure plate after rough milling and the first semi-finish milling. This reduces deformation caused by elastic recovery of the part, thus avoiding deviations between measured and actual machining values ​​due to deformation and preventing dimensional instability. During the second semi-finish milling, only the upper sidewall is machined. Then, further finishing is performed by machining the upper sidewalls of the groove one by one, and then machining the corresponding lower sidewalls according to the actual thickness of each upper sidewall. This allows the upper and lower sidewalls of each groove to be independently finished based on the measured data of their respective positions, compensating for errors caused by inconsistencies in the height of the part's surface. It ensures that the symmetry of all radial grooves relative to the upper and lower end faces of the part meets the requirements, avoiding dimensional and symmetry deviations caused by a single tool-compensation machining.

[0050] The method disclosed in this embodiment is not limited to linkage rings, but can also be applied to other thin-walled annular parts that require the machining of multiple radial grooves on the inner sidewall, such as gas turbine sealing rings, bearing cages, and missile servo housings. The resulting parts all have the common characteristics of high symmetry and low deformation.

[0051] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for machining radial grooves in a thin-walled annular part, characterized in that, Includes the following steps: S1: The thin-walled annular part to be processed is clamped onto the tooling using a pressure plate; S2: Rough mill each radial groove on the thin-walled annular part to be machined; S3: Perform the first semi-finish milling on each radial groove; S4: After loosening the pressure plate, tighten it again to make the end face of the part runout within the preset range; S5: Perform a second semi-finish milling on the upper sidewalls of each radial groove; S6: Obtain the total thickness of the part, the actual thickness of the upper sidewall, and the height of each radial groove; determine the actual machining thickness of the upper sidewall; perform finishing machining on the upper sidewall based on the actual machining thickness of the upper sidewall; and complete the machining of the upper sidewall. S7: Based on the upper sidewall thickness after S6 machining, the total thickness of the part, the height of each radial groove, and the tool width, determine the actual machining thickness of the lower sidewall. Perform finishing machining on the lower sidewall according to the actual machining thickness to complete the machining of the lower sidewall.

2. The method for machining a radial groove in a thin-walled annular part according to claim 1, characterized in that, The actual machining thickness of the upper sidewall is calculated using the following formula: B1 = A1 - (AH) / 2 + D Where A1 is the actual measured thickness of the upper sidewall of the groove; A is the total thickness of the part; H is the height of the groove; and D is the point value corresponding to the machining allowance during the second semi-finish milling.

3. The method for machining radial grooves in a thin-walled annular part according to claim 2, characterized in that, During the second semi-finish milling, the point value D corresponding to the machining allowance is calculated using the following formula: D = 0.5H - 0.5dC Where C is the machining allowance during the second semi-finish milling; d is the width of the milling cutter.

4. The method for machining a radial groove in a thin-walled annular part according to claim 1, characterized in that, The actual machined thickness of the lower sidewall is calculated using the following formula: B2 = A1 - (AH) / 2 + D - 0.5d + E Where A1 is the actual measured thickness of the upper sidewall of the groove; A is the total thickness of the part; H is the height of the groove; D is the point value corresponding to the machining allowance during the second semi-finish milling; d is the width of the milling cutter; and E is the thickness allowance of the lower sidewall left after the first semi-finish milling.

5. The method for machining a radial groove in a thin-walled annular part according to claim 1, characterized in that, In S2, when rough milling each radial groove, a layered milling method is adopted.

6. The method for machining a radial groove in a thin-walled annular part according to claim 1, characterized in that, In S3, during the first semi-finish milling, a allowance of 0.25-0.3mm is reserved.

7. The method for machining a radial groove in a thin-walled annular part according to claim 1, characterized in that, In S5, during the second semi-finish milling, the machining allowance is 0.1-0.15mm.

8. A method for machining a radial groove in a thin-walled annular part according to claim 1, characterized in that, In step S4, after loosening the pressure plate, the pressure plate is tightened again so that the end face runout of the part is less than or equal to 0.02mm.

9. A method for machining a radial groove in a thin-walled annular part according to claim 1, characterized in that, In step S7, after finishing the lower sidewall, the actual height of each groove is measured. If the height does not reach the pre-machined height of each radial groove, fine milling is performed by adjusting the tool compensation until the groove design height is reached.

10. A thin-walled annular part, characterized in that, It includes several grooves distributed on the inner sidewall of a thin-walled annular part, the grooves being obtained by the processing method described in claim 1.

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