Design method for low-speed wire cutting process of high-precision turbine disc mortise

Abstract

The invention provides a design method of a low-speed wire cutting process for a mortise of a high-precision turbine disc. The design method comprises the following steps: step 1, selecting wire cutting equipment; 2, verifying the machining precision of the equipment; 3, designing a test piece clamping scheme; step 4, performing linear cutting and rough opening processing on the test piece; step 5, performing linear cutting and fine cutting processing on the test piece, and performing linear cutting processing according to the final required shape of the tongue-and-groove design of the test piece; step 6, monitoring the linear cutting deformation of the test piece, selecting axial and radial representative characteristics on the test piece to monitor the size and technical conditions in the machining process, and forming a whole process record; and step 7, performing linear cutting processing on the formal part, and completing processing of the formal part according to the steps 3-6 performed on the test piece. The method has the advantages that high-precision control of the mortise can be realized by using the process scheme, the deformation of the part in a free state can be controlled within 0.02 mm, the deformation control state of the part is excellent, and greater value is created.

Description

Technical Field

[0001] The invention relates to the technical field of aeroengine manufacturing, and in particular to a method for designing a process for high-precision turbine disc tenon and groove slow-wire cutting. Background Art

[0002] The turbine disk is the component with the heaviest thermal and mechanical loads in the engine, so the materials used for the turbine disk are all high-hardness, difficult-to-cut high-temperature alloys and powder alloys. Especially for the processing of the mortise and tenon parts, the conventional broaching scheme has the problem of residual stress release during broaching, resulting in excessive deformation of the parts and scrapping. The inability to achieve low-stress and high-precision processing to achieve qualified mortise and tenon and control the overall deformation of parts has become a key bottleneck issue that restricts whether the parts can be delivered in a qualified manner. Summary of the invention

[0003] The purpose of the present invention is to process the tenon and groove of the turbine disk. The conventional broaching scheme has the problem of releasing residual stress of the parts as the material is removed by broaching, resulting in the deformation of the parts exceeding the tolerance and being scrapped. It is impossible to achieve low-stress and high-precision processing to achieve qualified tenon and groove and control the overall deformation of the parts, which becomes the key and bottleneck problem restricting whether the parts can be delivered qualified. The present invention adopts a full-process solution design of slow-wire cutting for the processing technology of the tenon and groove structure, and conducts all tests and engineering verifications, so as to achieve low stress in the process of precise manufacturing control of the tenon and groove structure, control the deformation of the entire part, and ensure the overall processing accuracy of the part. The process method is mastered for the subsequent low-stress and high-precision processing of the key matching structure of the tenon and groove of this family of parts, and the core processing technology of the key matching structure of the tenon and groove is accurately mastered.

[0004] The present invention provides a method for designing a process for high-precision turbine disc tenon and groove slow-wire cutting, comprising the following steps:

[0005] Step 1: Select wire cutting equipment. According to the diameter and height of the parts, select wire cutting equipment with a processing stroke that meets the requirements;

[0006] Step 2: Verify the processing accuracy of the equipment. Select a test piece with the same material as the part, perform wire cutting processing according to the mortise and tenon shape required by the design, and test the accuracy according to the design requirements;

[0007] Step 3, design of test piece clamping scheme. Select structural parts with the same dimensions as the formal part clamping alignment position and the mortise and tenon processing position to design the part clamping scheme, including the machine tool interface, angular position, and clamping position;

[0008] Step 4: Wire cutting rough opening of the test piece. A certain amount of allowance is offset and the local shape is simplified according to the final groove shape of the test piece to form a rough opening shape, and then wire cutting is performed;

[0009] Step 5: Wire cutting and finishing of the test piece. Wire cutting is performed according to the final required shape of the mortise and tenon design of the test piece;

[0010] Step 6: Monitoring the deformation of the test piece during wire cutting. Select representative axial and radial features on the test piece to monitor the dimensions and technical conditions during the processing and form a record of the entire process;

[0011] Step 7: Wire cutting of the actual part. Follow steps 3-6 of the test piece to complete the processing of the actual part.

[0012] Aiming at the difficulty in machining the tenon and groove of a turbine disk, the present invention develops a high-precision slow-wire cutting tenon and groove machining process method, which realizes precise control of the tenon and groove structure, low-stress machining during the process, and control of deformation of the entire part, thereby ensuring the overall machining accuracy of the part.

[0013] Compared with the prior art, the present invention has the following advantages:

[0014] The process scheme of the present invention can realize high-precision control of the mortise and tenon, and the deformation of the parts in a free state can be controlled within 0.02 mm. The deformation control state of the parts is extremely good, creating greater value. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments:

[0016] Figure 1 A flow chart of a process design method for high-precision turbine disc tenon and groove slow-wire cutting;

[0017] Figure 2 A schematic diagram of the equipment identified in the case of the present invention;

[0018] Figure 3 A schematic diagram of the mortise and tenon groove shape processed for the test piece used to verify the accuracy of the equipment in the case of the present invention;

[0019] Figure 4 A schematic diagram of a tongue-and-groove fixture connected to a device in a case of the present invention;

[0020] Figure 5 It is a schematic diagram of a positioning block used for angular alignment transfer during the processing of the case of the present invention;

[0021] Figure 6 It is a simplified schematic diagram of the shape of the mortise and tenon before and after rough opening in the case of the present invention;

[0022] Figure 7 This is a schematic diagram of the test piece after all the mortise and tenon grooves are processed in the case of the present invention;

[0023] Figure 8 This is a schematic diagram of selecting measurement locations in the axial and radial directions of a part in the case of the present invention. DETAILED DESCRIPTION

[0024] The present invention will be further explained below in conjunction with specific implementation plans, but the present invention is not limited thereto. The structures, proportions, sizes, etc. illustrated in the drawings of the specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the restrictive conditions under which the present invention can be implemented. Therefore, they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0025] The present invention aims at the processing of the tenon and groove of the turbine disk. The conventional broaching scheme has the problem of releasing residual stress of the parts as the material is removed by broaching, which leads to the deformation of the parts and the scrapping. It is impossible to achieve low-stress and high-precision processing to achieve qualified tenon and groove and control the overall deformation of the parts, which becomes the key and bottleneck problem that restricts whether the parts can be delivered in a qualified manner. A high-precision turbine disk tenon and groove slow-wire cutting process design method is invented to achieve precision manufacturing control of the tenon and groove structure and realize low stress in the process, control the deformation of the entire part, and ensure the overall processing accuracy of the part. The process method is mastered for the subsequent low-stress and high-precision processing of the key matching structure of the tenon and groove of this family of parts, and the core processing technology of the key matching structure of the tenon and groove is accurately mastered. The present invention takes a certain type of powder alloy turbine disk part of an aircraft engine as an example to introduce the high-precision turbine disk tenon and groove slow-wire cutting process design scheme. The present invention is further explained in conjunction with the accompanying drawings and embodiments below.

[0026] 1) Select the wire cutting equipment, the maximum outer diameter of the part is 580mm, the total height of the part is 319.2mm, and the processing stroke is 600mm. The slow wire cutting equipment model that meets the requirements is Japan Sodick ANL600Qs, such as Figure 2 ;

[0027] 2) Equipment processing accuracy verification. Select a test piece with the same material as the part, FGH99, with an outer diameter of Φ200mm and a slot type that is the difference size in the design drawing. Complete wire cutting and test and verify the slot geometry accuracy, slot uniformity, and slot roughness as three indicators. The test results are: profile 0.01mm, uniformity 0.02mm, and roughness Ra0.68μm, which all meet the design requirements: profile 0.05mm, uniformity 0.05mm, and roughness Ra0.80μm. Figure 3 ;

[0028] 3) Design of test piece clamping scheme. Select structural parts with the same dimensions as the formal part clamping and alignment parts and the mortise and tenon processing parts to design the part clamping scheme, including the machine tool interface, angular position, and clamping part.

[0029] First of all, considering that the equipment structure is non-rotary, the fixture design mainly supports the parts and precisely cooperates with the workbench through bolts. It is connected to the machine tool through bolts to support the parts. The parts are clamped by 8 pressure plates. To ensure the accuracy of the fixture, the surface runout of the fixture is aligned, and the surface runout does not exceed 0.01mm; check that the height of the two parts of the fixture must be consistent, and the height difference is controlled within 0.01mm. Complete the part clamping and alignment, such as Figure 4 ;

[0030] Secondly, the processing area of ​​the parts is 360°. The processing area of ​​non-rotary parts needs to be completed in sequence according to the travel range of the wire feeding, and all processing is completed in the same angular direction. In order to meet the angular requirements, two evenly distributed precision blind holes are added to the uncut parts of the online cutting mortise and tenon. According to the size of the mortise and tenon, a blind hole with a diameter of Φ3.55+0.01+0.005m and a depth of 5mm is designed. A positioning block is manufactured to match the two precision blind holes. The structure is as follows Figure 5 , a 3.55mm measuring rod is fixed on the part to transfer the alignment reference of the wire cutting area processing. After the wire cutting is completed, the mortise and tenon of the blind hole is processed into a complete groove shape to complete all processing and realize the complete processing of the part;

[0031] 4) Wire cutting rough opening of the test piece. In order to avoid deformation release caused by wire cutting to the final groove shape once, resulting in the groove shape size and position deviation, wire cutting with sufficient margin is rough opening. Taking the wire cutting groove shape as the reference, 2mm is evenly left along the groove shape. At the same time, the diameter of the wire cutting wire is Φ0.25mm. The wire cutting processing is easy to break the wire at the local sharp point. The groove shape is simplified to effectively avoid wire breakage and improve processing efficiency. The front and rear groove shapes are simplified as follows: Figure 6 ;

[0032] 5) Wire cutting and finishing of the test piece. Wire cutting is performed according to the final required shape of the test piece’s mortise and tenon design. The groove shape after processing is as follows: Figure 7 ;

[0033] 6) Monitoring of wire cutting deformation of test pieces. Select representative axial and radial features on the test pieces to monitor the dimensions and technical conditions during the processing, such as Figure 8 , forming a record of the whole process;

[0034] 7) Formal wire cutting of parts. Press the parts according to the clamping method of the test piece, perform wire cutting, and monitor the process.

[0035] Matters not covered by the present invention are known technologies.

[0036] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-precision turbine disc tenon and groove slow-wire cutting process design method, characterized by: The following steps are involved: Step 1: Select wire cutting equipment. According to the diameter and height of the parts, select wire cutting equipment with a processing stroke that meets the requirements. The height direction must ensure that the wire does not interfere with the wire during wire cutting, and the diameter direction must ensure that the equipment stroke can complete the processing of the entire area. Step 2: Verify the processing accuracy of the equipment; select a test piece with the same material as the part, perform wire cutting processing according to the mortise and tenon shape required by the design, and test the accuracy according to the design requirements; Step 3, design of test piece clamping scheme: select structural parts with the same dimensions as the formal part clamping alignment position and the mortise and tenon processing position to design the part clamping scheme, including three parts: machine tool interface, angular position, and clamping position; Step 4: rough cutting of the test piece by wire cutting; a 1-2mm size offset and local shape simplification are performed on the final groove shape of the test piece to form a rough opening shape, and then wire cutting is performed; Step 5: Wire cutting and finishing of the test piece; wire cutting is performed according to the final required shape of the mortise and tenon design of the test piece; Step 6: Monitoring the deformation of the test piece during wire cutting; selecting representative axial and radial features on the test piece to monitor the dimensions and technical conditions during the processing and form a record of the entire process; Step 7: Wire cutting of the formal part; complete the processing of the formal part according to steps 3-6 of the test piece.

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