A machining method for long cantilevered unsupported gyrad parts

Abstract

The application relates to a machining method for a long cantilever non-supporting rotary body part, which comprises the following steps: forging a blank, clamping the blank on a lathe after meeting the technical requirements; rough turning one end; rough turning the other end; semi-precision turning one end; semi-precision turning the other end; vacuum stress relieving the part; precision turning the inner cavity; clamping the blank on the lathe through a deformation-preventing tool, and then precision turning the outer contour; milling an opening groove; deburring; wire cutting type groove; bench work polishing; marking; ultrasonic cleaning the part; and testing according to the testing chart size. Through the method, the long cantilever non-supporting rotary body part is machined once to meet the requirements, the machining method of the large-suspension deep-thin-wall cavity cone structure part is mastered, cost is saved, and great economic losses caused by waste products are avoided; meanwhile, technical experience is accumulated for machining of subsequent other types of similar structure parts.

Description

Technical Field

[0001] The present invention belongs to the technical field of aero-engine manufacturing, and in particular relates to a method for processing a long cantilever unsupported rotary part, which is used for processing the inner cavity of the long cantilever and the inner and outer contours of a precision cone of an aero-engine part. Background Art

[0002] In aircraft engines, the existing parts with a structure similar to the cap cover have a simple structure and can be completed in one step by stamping. However, the cap cover is a long cantilevered, unsupported rotating part. This part belongs to a new structural type and is mainly composed of two parts: a precision conical outer contour and an inner cavity with a long cantilevered stepped shaft. An analysis of the part structure revealed the following five machining difficulties: 1. A large amount of material is removed during the machining process from the forging blank to the finished product, generating a significant amount of cutting heat that can easily burn the part surface. Furthermore, long tool passes can cause tool wear due to cutting vibration, making it difficult to guarantee dimensional and technical requirements. 2. The part's shape is an irregular curved surface and a thin-walled, hollow cone structure, lacking a suitable clamping and positioning reference for finishing. 3. The lack of effective support within the part's interior results in a severe lack of rigidity. During machining, the clamping force, cutting force, and gravity, combined with the direction of the cutting force constantly changing with the curve, can easily cause uncontrollable deformation of the thin-walled structure, making it difficult to guarantee the final dimensions of the part. 4. The deepest part's interior cavity is 180 mm, requiring a minimum tool extension of approximately 250 mm. This lack of rigidity during turning compromises the dimensional accuracy and surface quality of the part's interior cavity. 5. Standard tools cannot meet machining requirements for machining the inner hole of a stepped shaft, requiring the use of non-standard tools tailored to the part's structural characteristics and requirements for chip removal and cooling. To sum up, there is no reliable processing experience for this structural part. There is an urgent need for a processing method for long cantilevered, unsupported rotating parts such as caps. It is necessary to explore and innovate in the formulation of process routes, selection of tool structures, and selection of processing parameters. Summary of the Invention

[0003] In view of the shortcomings of the existing technology, the present invention provides a processing method for long cantilever unsupported rotating body parts to ensure qualified delivery of parts.

[0004] A method for processing a long cantilever unsupported rotating body part specifically comprises the following steps:

[0005] Step 1: Forge the raw material and clamp it on the lathe after it meets the technical requirements;

[0006] Step 2: Rough turning one end;

[0007] Step 3: Rough turn the other end;

[0008] Step 4: Semi-finish turning one end;

[0009] Step 5: Semi-finish turning the other end;

[0010] Step 6: Vacuum stress relief on parts;

[0011] Step 7: Finish turning the inner cavity;

[0012] Step 8: Clamp the rough material on the lathe through the anti-deformation tooling, and then fine-turn the outer contour;

[0013] Step 9: Milling the opening slot;

[0014] Step 10: Deburring;

[0015] Step 11: Wire cutting groove;

[0016] Step 12: Bench grinding;

[0017] Step 13: Marking;

[0018] Step 14: Ultrasonic cleaning of parts;

[0019] Step 15: Inspect according to the dimensions on the inspection chart.

[0020] Steps 1 to 5 are all rough machining processes, and there are no specific requirements for parameters.

[0021] In step seven, when processing the inner cavity of the part in partitions, tool rods with different curvature radii are selected according to the changes in the inner cavity surface of the part. At the same time, considering that the inner cavity is a closed structure and the coolant cannot be directly poured onto the processing surface during processing, a tool rod and blade with an internal cooling structure are selected; at the same time, since chip removal is difficult during closed structure processing, the tool rod protruding too long when processing the deepest part of the inner cavity will result in serious lack of rigidity, so a tool rod equipped with a shock absorber is selected.

[0022] The anti-deformation tooling in step eight includes a base, a screw, a rubber gasket, and a nut. The base is a multi-section rotating disc base, one end of which is clamped on the lathe by a chuck, and the other end is provided with a precision positioning stop. A screw is fixed in the middle of the base along the central axis, and the precision positioning stop is used to cooperate with the inner hole formed by the fine-machined inner cavity of the part to ensure positioning accuracy. Rubber gaskets are evenly distributed along the circumference of the cooperation between the precision positioning stop and the inner hole to play an auxiliary support role, thereby eliminating axial cutting stress. The part is fixed on the anti-deformation tooling through the connection between the nut and the screw.

[0023] The screw, rubber gasket, nut and gasket in the anti-deformation tooling are all purchased standard parts.

[0024] The steps 7 and 8 are the finishing process, which are mainly divided into two parts: finishing the inner cavity and finishing the outer contour. The inner cavity is composed of two parts: the inner cavity of the cone and the cantilever step shaft. When finishing the inner cavity, as the processing depth is different, the farther the processing position is from the clamping position, the worse the rigidity of the part is. At the same time, as the cutting inner cavity goes deeper, the direction of the cutting force will also change at any time. Therefore, during the entire finishing process, the finishing outer contour, the finishing cone inner cavity, and the finishing cantilever step shaft must adjust the processing parameters in time according to the changes in the processing position. The specific processing parameters of each part are: when finishing the outer contour, the linear speed is constant at 55m / min, the cutting depth is 0.5mm, and the feed is 0.08mm / r; when finishing the cone inner cavity, the linear speed is constant at 55m / min, the cutting depth is 1mm, and the feed is 0.05mm / r; when finishing the cantilever shaft, the rotation speed is 200r / min, the cutting depth is 1mm, and the feed is 0.03mm / r.

[0025] Depending on the processing position, the parameter selection is different. When the surface quality of the processing position is Ra1.6 or above, the constant linear speed cutting method is selected; the linear speed value is different for different turning radius of the part processing position. When the turning radius is less than 60mm, the linear speed is controlled between 45 and 60m / min; when the turning radius is 60 to 150mm, the linear speed is controlled between 25 and 45m / min; at the position where the surface quality of the processing position is below Ra1.6, the constant speed S = 180 to 240rpm cutting method is selected; no matter which method is selected, the cutting depth does not exceed 1mm during fine turning, and the feed is controlled at 0.03 to 0.1mm / r.

[0026] The beneficial effects of the present invention are:

[0027] (1) By analyzing the part structure and rationally arranging the process route, the impact of machining stress release on size and technical conditions can be minimized.

[0028] (2) According to the structural characteristics of different positions in the zero cavity and combined with the chip removal and cooling requirements, tools with different curvature radii are selected.

[0029] (3) Considering the lack of rigidity of the overall structure of the parts, avoid clamping and local point pressing when selecting the positioning reference and clamping method, and choose anti-deformation tooling that uses surface pressing and adds elastic auxiliary support for processing.

[0030] (4) In order to ensure the surface quality of the inner and outer contours of the parts and the accuracy of the inner cavity dimensions, the processing parameters are repeatedly explored when processing different positions and the optimal parameters are selected for solidification.

[0031] The method provided in this application enables the first-pass machining of this long-cantilevered, unsupported rotating component, mastering the machining method for thin-walled, hollow cone-shaped components with large overhang depths, saving costs and avoiding significant economic losses caused by scrap. It also accumulates technical experience for the subsequent machining of other similar structural components. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic diagram of parts provided in an embodiment of the present invention;

[0033] Figure 2 for Figure 1 A-direction view;

[0034] Figure 3 for Figure 1 B-direction view;

[0035] Figure 4 for Figure 2 AA view;

[0036] Figure 5 This is a schematic diagram of the clamping state of the anti-deformation tooling in the present invention;

[0037] Figure 6 for Figure 5 AA view;

[0038] Figure 7 Schematic diagram of the base in the anti-deformation tooling of the present invention;

[0039] Figure 8 A schematic diagram of the machining process of fine turning the outer contour in the method provided in an embodiment of the present invention;

[0040] in,

[0041] 1-base, 2-screw, 3-rubber gasket, 4-nut. DETAILED DESCRIPTION

[0042] In order to better explain the present invention and facilitate understanding, the technical solutions and effects of the present invention are described in detail below with reference to the accompanying drawings through specific implementation methods.

[0043] The cap part is a thin-walled cavity structure. A large amount of cutting stress will be generated in the process of machining the part from the free forging blank to the finished product. In order to avoid the influence of stress release on the dimensional accuracy of the part, the process route should be formulated in the order of rough machining-semi-finishing-stress relief-finishing to minimize the influence of stress release on the size and technical conditions. Therefore, a machining method for long cantilever unsupported rotary parts, such as Figure 1-4As shown, taking the following cap part as an example, the dimensional parameters of the cap are: the maximum outer diameter of the part is 240mm, the length is 188mm, the end face of the stepped shaft has a 12mm deep groove, the minimum wall thickness of the outer cone is only 3.5mm, the contour requirement is 0.1mm, and the dimensional tolerance of the boss intersecting the cone surface is only 0.029mm. The specific steps include:

[0044] Step 1: Forge the raw material and clamp it on the lathe after it meets the technical requirements;

[0045] Step 2: Rough turning one end;

[0046] Step 3: Rough turn the other end;

[0047] Step 4: Semi-finish turning one end;

[0048] Step 5: Semi-finish turning the other end;

[0049] The above steps are all rough processing processes, and there are no specific requirements for parameters.

[0050] Step 6: Vacuum stress relief on the parts; this step is located between the semi-finishing and finishing processes. The purpose of this vacuum stress relief arrangement is to eliminate the processing stress accumulated after the parts have removed a large amount of material, laying the foundation for the finishing process.

[0051] Step 7: Finish turning the inner cavity; In order to overcome the influence of surface changes on the unstable cutting force and increase the structural rigidity of the parts during machining, the partitioning method is used to eliminate unstable factors when machining the inner cavity of the parts.

[0052] When processing the inner cavity of a part in a partitioned manner, tool holders with different curvature radii are selected according to the changes in the inner surface of the part. At the same time, considering that the inner cavity is a closed structure and the coolant cannot be directly poured onto the processing surface during processing, tool holders and blades with an internal cooling structure are selected. At the same time, since chip removal is difficult during closed structure processing, the tool holder protruding too long when processing the deepest part of the inner cavity will result in serious lack of rigidity, so a tool holder equipped with a shock absorber is selected.

[0053] Step 8: Clamp the rough material on the lathe through the anti-deformation tooling, and then fine-turn the outer contour;

[0054] Since the overall structural rigidity of the cap cover parts is insufficient, the tooling should avoid clamping and point pressing methods. The processing accuracy can be guaranteed by adopting surface pressing and adding elastic auxiliary support structure for processing.

[0055] like Figure 5-6 As shown, the anti-deformation tooling includes a base 1, a screw 2, a rubber gasket 3, and a nut 4. Figure 7As shown, the base 1 is a multi-section rotary disc base 1, one end of which is clamped on the lathe by a chuck, and the other end is provided with a precision positioning stop; a screw 2 is fixed in the middle of the base 1 along the central axis, and the precision positioning stop is used to cooperate with the inner hole formed by the fine-machined inner cavity of the part to ensure positioning accuracy; rubber gaskets 3 are evenly distributed along the circumference of the cooperation between the precision positioning stop and the inner hole to play an auxiliary support role, thereby eliminating axial cutting stress, and the part is fixed on the anti-deformation tooling through the connection between the nut 4 and the screw 2, as shown in FIG. Figure 8 The screw 2, rubber gasket 3, nut 4 and gasket in the anti-deformation fixture are all purchased standard parts.

[0056] According to the process route, steps seven and eight are the finishing process, which is mainly divided into two parts: finishing the inner cavity and finishing the outer contour. The inner cavity consists of the cone inner cavity and the cantilever step shaft. When finishing the inner cavity, the farther the processing position is from the clamping position, the worse the rigidity of the part. At the same time, as the cutting depth of the inner cavity is deepened, the direction of the cutting force will also change at any time. Therefore, during the entire finishing process, the finishing parameters of the outer contour, the cone inner cavity, and the cantilever step shaft must be adjusted in time according to the changes in the processing position. This is to ensure both part processing quality and improve part processing efficiency. The specific processing parameters for each part are as follows: when finishing the outer contour, the linear speed is constant at 55m / min, the cutting depth is 0.5mm, and the feed is 0.08mm / r; when finishing the cone inner cavity, the linear speed is constant at 55m / min, the cutting depth is 1mm, and the feed is 0.05mm / r; when finishing the cantilever shaft, the speed is 200r / min, the cutting depth is 1mm, and the feed is 0.03mm / r.

[0057] As mentioned above, the parameter selection varies depending on the processing location. When the surface quality of the processing location is above Ra1.6, the constant linear speed (V) cutting method is selected. This selection is conducive to controlling the stability of the cutting process and improving the surface quality. The linear speed (V) value varies depending on the rotation radius of the part processing location. When the rotation radius is less than 60mm, the linear speed is controlled between 45 and 60m / min; when the rotation radius is 60 to 150mm, the linear speed is controlled between 25 and 45m / min. At the position where the surface quality of the processing location is below Ra1.6, the constant speed (S = 180 to 240rpm) cutting method is selected. This selection is conducive to improving the processing efficiency of the part and controlling the dimensional accuracy of the part. Regardless of which method is selected, the cutting depth (AP) during fine turning does not exceed 1mm, and the feed (F) is controlled at 0.03 to 0.1mm / r.

[0058] The anti-deformation tooling is only used for the eighth step of the fine turning process of the outer contour, and the other processes can use the universal tooling.

[0059] Step 9: Milling the opening slot;

[0060] Step 10: Deburring;

[0061] Step 11: Wire cutting groove;

[0062] Step 12: Bench grinding;

[0063] Step 13: Marking;

[0064] Step 14: Ultrasonic cleaning of parts;

[0065] Step 15: Inspect according to the dimensions on the inspection chart.

[0066] Through the above method, the cap part can be processed qualifiedly in one time, which greatly shortens the scheduled processing cycle. The surface quality and contour of the part's outer contour meet the requirements of the design drawings, and there are no cutting marks on the inner cavity surface, which is better than the requirements of the design drawings. At the same time, the processing method of thin-walled cavity cone structure parts is mastered, providing experience for the processing of similar parts in the future.

Claims

1. A method for processing long cantilever unsupported rotating parts, characterized in that: The specific steps include: Step 1: Forge the raw material and clamp it on the lathe after it meets the technical requirements; Step 2: Rough turning one end; Step 3: Rough turn the other end; Step 4: Semi-finish turning one end; Step 5: Semi-finish turning the other end; Step 6: Vacuum stress relief on parts; Step 7: Finish turning the inner cavity; Step 8: Clamp the rough material on the lathe through the anti-deformation tooling, and then fine-turn the outer contour; The steps 7 and 8 are the finishing process, which are mainly divided into two parts: finishing the inner cavity and finishing the outer contour. The inner cavity is composed of two parts: the inner cavity of the cone and the cantilever step shaft. When finishing the inner cavity, as the processing depth is different, the farther the processing position is from the clamping position, the worse the rigidity of the part is. At the same time, as the cutting inner cavity goes deeper, the direction of the cutting force will also change at any time. Therefore, during the entire finishing process, the finishing outer contour, the finishing cone inner cavity, and the finishing cantilever step shaft must adjust the processing parameters in time according to the changes in the processing position. The specific processing parameters of each part are: when finishing the outer contour, the linear speed is constant at 55m / min, the cutting depth is 0.5mm, and the feed is 0.08mm / r; when finishing the cone inner cavity, the linear speed is constant at 55m / min, the cutting depth is 1mm, and the feed is 0.05mm / r; when finishing the cantilever shaft, the rotation speed is 200r / min, the cutting depth is 1mm, and the feed is 0.03mm / r. Step 9: Milling the opening slot; Step 10: Deburring; Step 11: Wire cutting groove; Step 12: Bench grinding; Step 13: Marking; Step 14: Ultrasonic cleaning of parts; Step 15: Inspect according to the dimensions on the inspection chart.

2. A method for processing a long cantilever unsupported rotating part according to claim 1, characterized in that: Steps 1 to 5 are all rough machining processes, and there are no specific requirements for parameters.

3. The method for processing a long cantilever unsupported rotating part according to claim 1, characterized in that: In step seven, when processing the inner cavity of the part in partitions, tool rods with different curvature radii are selected according to the changes in the inner cavity surface of the part. At the same time, considering that the inner cavity is a closed structure and the coolant cannot be directly poured onto the processing surface during processing, a tool rod and blade with an internal cooling structure are selected; at the same time, since chip removal is difficult during closed structure processing, the tool rod protruding too long when processing the deepest part of the inner cavity will result in serious lack of rigidity, so a tool rod equipped with a shock absorber is selected.

4. The method for processing a long cantilever unsupported rotating part according to claim 1, characterized in that: The anti-deformation tooling in step eight includes a base, a screw, a rubber gasket, and a nut. The base is a multi-section rotating disc base, one end of which is clamped on the lathe by a chuck, and the other end is provided with a precision positioning stop. A screw is fixed in the middle of the base along the central axis, and the precision positioning stop is used to cooperate with the inner hole formed by the fine-machined inner cavity of the part to ensure positioning accuracy. Rubber gaskets are evenly distributed along the circumference of the cooperation between the precision positioning stop and the inner hole to play an auxiliary support role, thereby eliminating axial cutting stress. The part is fixed on the anti-deformation tooling through the connection between the nut and the screw.

5. The method for processing a long cantilever unsupported rotating part according to claim 4, characterized in that: The screw, rubber gasket, nut and gasket in the anti-deformation tooling are all purchased standard parts.

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