Method for roughly machining blade body of small-allowance blade

Abstract

The invention relates to a method for roughly machining a blade body of a small-allowance blade. The periphery of a machined part is suspended, cutting-in of a cutter is facilitated, chip removal is convenient, and the tool is designed to reduce deformation of the machined part and meet the size requirement. The machined part is small in deformation, the size is easy to guarantee, the time for clamping and disassembling the part is saved, the efficiency is improved, and the cost is saved.

Description

Technical Field

[0001] The present invention relates to a fixture tooling that can machine the blade basin and blade back after clamping the blade once and flipping the positioning plate, and particularly to a method for rough machining the blade body with a small allowance, which is used for rough machining small-allowance blade parts of aero-engines and belongs to the field of machine tool tooling components. Background Art

[0002] The rough milling of the blade body profile by a three-axis machining center is increasingly widely used in the machining field of aero-engine blade parts. Considerations are given to economy, especially the application of tooling on complex curved surfaces and other difficult-to-machine surfaces.

[0003] Most aero-engine blades are forged blanks with a large allowance. It is difficult to rough mill the blade body profile after machining the positioning surface. Previously, on a conventional milling machine, profiling milling or copy milling was used for machining, and a large number of forming tools were used. During machining, due to the large diameter of the tool, the resistance was also large, and the blade body was prone to deformation, resulting in low machining efficiency. The existing profile machining tooling is to remove the part after machining the blade basin, then turn it over and clamp it on another tooling to machine the blade back. When the part is removed after machining one side, the blade body deforms or twists due to the reduction of the allowance on one side, and the large deformation is not conducive to controlling the dimensions. With the continuous progress of technology, the rapid development of artificial intelligence and the research and manufacture of advanced equipment, the role of tooling in blade machining is becoming more and more important. If directly rough machining on a five-axis blade machining center, the cost is relatively high and the machining efficiency is relatively low. On the premise of considering cost savings, when rough machining blades on a three-axis machining center, different toolings can be used to achieve cutting machining of different profiles. The main function of the newly designed tooling is to reduce the deformation of the part caused by the tool cutting the surface material of the part when removing the profile allowance during machining. By relying on the pressing force (tension force) of the pressing plate being greater than the deformation shrinkage force of the part during the initial clamping, the process table and the tenon end face are fixed on the fixture. After machining one side, the part does not need to be disassembled and reinstalled. The base remains stationary, but the upper frame of the tooling is flipped as a whole and fixed, and then the other side can be directly machined. It has the characteristics of convenient clamping, flexibility, accurate positioning, and small deformation of the blade body of the part after machining. It is particularly suitable for batch machining of small-allowance blades. Summary of the Invention

[0004] The purpose of the present invention is to overcome the disadvantage of large deformation of the blade body after machining by the existing tooling, meet the machining quality of the product, reduce the production cost and improve the efficiency, and provide a fixture tooling with a supporting, tensioning and positioning function, which clamps the machining part of the part on the tooling at one time, and machines the blade basin and blade back by flipping the positioning frame as a whole.

[0005] The technical solution of the present invention is as follows: A method for rough machining the blade body with a small allowance, characterized by at least including: a tooling base assembly 1 (including a baffle 5, a stud 20, and an inner hexagon screw 24), a turning plate assembly 2 (including a positioning block 3, a support block 4, a support 6, a positioning pin 7, a pressing plate 8, a pressing plate 9, and a process table positioning block 17). The tooling base assembly 1 includes a boss positioning surface 11 and a boss side positioning surface 12. There are two groups of positioning key grooves 10 on the middle boss surface of the boss positioning surface 11, and a positioning surface 12 and a positioning surface 13 on the boss side. The stud 20 and a hexagon flange nut 21; The turning plate assembly 2 includes upper and lower positioning surfaces 14, 15, a tenon basin side positioning surface 16, a process table positioning block 17, a positioning pin 7, a pressing plate 8, a pressing plate 9, a support 6, an exhaust edge tenon side positioning block 3, an inlet edge tenon side support block 4, a smooth surface pressing block 18, four positioning keys 19 in the middle of the turning plate, inner hexagon screws 22, 24, 25, 27, 29, a cylindrical pin 28, a hexagon head bolt 23, a process hole 30, etc. The parts are fixed on the process table side of the turning plate 2 with the process table positioning block 17, the positioning pin 7, the pressing plate 8, the support 6, and the hexagon head bolt 23. The tenon side is positioned with the tenon basin side positioning surface 16 on the turning plate 2, the exhaust side of the tenon is positioned with the positioning block 3, the other side is fixed with the support block 4, the knurled screw 26, and the smooth surface pressing block 18, and the back side is fixed with the pressing plate 9, the support 6, and the hexagon head bolt 23. Finally, the turning plate 2 and the base 1 are positioned with the positioning key 19 and the baffle 5 and fixed with the nut 21, so that the large area of the blade profile is close to the plane, which is convenient for machining with a three-axis machining center.

[0006] The described tooling base assembly 1 is composed of a bottom plate and six bosses. The bottom surface of the boss bottom plate is parallel to the upper end surface 11 of the boss of the base 1, and the parallelism is not greater than 0.01 mm. The six bosses are required to have the same height, and the flatness is not greater than 0.01 mm. When the tooling is clamped, the bottom surface of the bottom plate is placed flat on the workbench and pressed tightly with screws at four U-shaped grooves. The alignment of the reference surface 12 of the base is not greater than 0.02 mm. Four studs 20 are connected and locked with the bosses, and the baffle 5 is connected to the base 1 with screws 24.

[0007] On the tenon side of the described turning plate assembly 2, the positioning block 3 is positioned and fixed on the turning plate 2 with 2 screws 29 (M6×25) and 2 cylindrical pins 28 (φ6×32). The contact surface of the positioning block 3 is perpendicular to the tenon basin side positioning surface 16 of the turning plate 2, and the perpendicularity is not greater than 0.01 mm. The longitudinal angle with the positioning surface 14 on the turning plate 2 ensures the dimension of 18°±0.5°. The support block 4 is fixed on the turning plate with 2 screws 25 (M5×16) and assembled with the knurled screw 26 and the smooth surface pressing block 18. The support 6 is assembled between the pressing plate 9 and the turning plate 2 to play a supporting role. After assembly, the contact surface of the pressing plate 9 is required to be parallel to the tenon basin side positioning surface 16 of the turning plate 2.

[0008] On the process table side of the flip plate assembly 2, it is positioned and fixed by the process table positioning block 17, 4 hexagon socket head cap screws 27 (M6×25), and 2 cylindrical pins 28 (φ6×32). Assemble the positioning pin 7 with the process table positioning block 17. After assembly, the lateral included angle between the positioning surface of the process table positioning block 17 and the positioning surface of the flip plate is ensured to be 18°±0.5°. The perpendicularity of the pin to the positioning surface is not greater than 0.01 mm. Then, connect the pressure plate 8 with hexagon head bolts 23 (M10×50), and assemble the support 6 between the pressure plate 8 and the flip plate 2 to play a supporting role. The pressing surface of the pressure plate is required to be parallel to the positioning surface of the process table positioning block 17.

[0009] After the flip plate assembly 2 is assembled, it is required that the positioning surface 16 on the mortise basin side is parallel to the positioning surface of the process table positioning block 17, and the parallelism is not greater than 0.01 mm. Ensure that the step difference dimension between the two positioning surfaces is 9.8±0.01 mm. The center of the positioning pin 7 and the contact surface between the mortise exhaust side positioning block 3 and the part are ensured to be 37.045±0.01 mm.

[0010] When machining the flip plate positioning surface 14 and the positioning surface 15, the parallelism between them is required to be not greater than 0.01 mm, and the perpendicularity to the side positioning surface is not greater than 0.015 mm.

[0011] All parts such as the base assembly 1, the flip plate assembly 2, the process table positioning block 17, the pressure plate 8, and the pressure plate 9 are made of 45 steel and need to go through a heat treatment process. The heat treatment hardness cannot be lower than HRC35. Among them, the positioning block 3 and the positioning pin 7 are made of CrWMn and the heat treatment hardness cannot be lower than HRC55. The surface roughness of the upper positioning surface, the lower positioning surface, and the side surface of the flip plate 2 reaches Ra0.8, and the surface roughness of the upper and lower positioning surfaces of the base 1 is also required to reach Ra0.8.

[0012] The installation sequence of this tooling is as follows: When loading and unloading parts, open the pressure plates 8 and 9, clamp the blade with the basin side facing downwards. The process hole of the blade has a clearance fit with the positioning pin 7. The positioning surface of the process table on the basin side of the blade is tightly attached to the positioning surface of the process table block 17 and is detected with a 0.02 mm feeler gauge. The reference surface on the exhaust side of the blade tenon is tightly attached to the positioning surface of the process table 3 and is detected with a 0.02 mm feeler gauge. The positioning surface of the blade tenon on the basin side is tightly attached to the positioning surface 16 on the basin side of the turning plate and is detected with a 0.02 mm feeler gauge. Gently lock the pressure plates 8 and 9 with bolts 23. After rotating the knurled screw 26 to drive the smooth pressing block 18 to tightly press the intake side of the blade tenon, tighten the bolts 23. Install the turning plate assembly 2 with the parts installed on it and the base 1. During installation, the process table is on the left side of the machine tool worktable. Place the blade back upwards. The positioning key 19 is engaged with the positioning key grooves 10 on the two middle bosses of the base 1. The side surface of the turning plate 2 is tightly attached to the baffle 5. The positioning surface 15 of the turning plate 2 is tightly attached to the six bosses of the base 1. The clearance at the tight attachment of the above-mentioned joint surfaces is detected with a 0.02 mm feeler gauge respectively. After confirming that the above clearances meet the requirements, tighten the nut 21. When machining the basin side of the blade, turn the turning frame 2 forward and backward and repeat the installation and inspection process with the base 1.

[0013] The advantages of the present invention are as follows: The machined parts are suspended around, which is conducive to the cutting tool to cut in and the chip removal is convenient. The purpose of designing this tooling is to reduce the deformation of the parts after machining and meet the dimensional requirements. Mainly, the pressing force (frictional force) of the pressure plates 8 and 9 of the turning plate 2 assembly on the upper and lower positioning surfaces of the blade tenon in the natural state is greater than the internal stress generated when the cutting tool removes the blank of the part during blade machining. The parts are not disassembled during one-time clamping. Since the blade is a forged blank, the internal stress carried by the black skin is relatively large. After removing the black skin on one side, the deformation tends to the machined surface, and the non-machined surface will also deform. The deformation generated during machining the basin side of the blade will not cause non-recoverable deformation due to the need to disassemble and assemble during turning over to machine the back of the blade. After one-time turning over of the turning plate 2 assembly, the parts are machined. In this way, the deformation of the machined parts is small, the dimensions are easy to guarantee, the time for clamping and disassembling parts is saved, and the efficiency is improved and the cost is saved.

[0014] The present invention will be further described below in conjunction with the accompanying drawings of the embodiments: Description of the Drawings Figure 1 Schematic structural diagram of the tooling of the present invention; Figure 2 Schematic structural diagram of the turning plate assembly; Figure 3 Schematic structural diagram of the base assembly; Figure 4 Schematic diagram of the blade clamping state; Figure 5 Before the tooling is turned over; Figure 6 After the tooling is turned over.

[0015] In the figure, 1. Base assembly; 2. Flip plate assembly; 3. Positioning block; 4. Support block; 5. Baffle; 6. Support; 7. Positioning pin; 8. Pressure plate; 9. Pressure plate; 10. Positioning keyway; 11. Boss positioning surface; 12. One-side positioning surface of the boss; 13. The other-side positioning surface of the boss; 14. Upper positioning surface of the flip frame; 15. Lower positioning surface of the flip frame; 16. Tenon side positioning surface of the flip frame on the basin side; 17. Process table positioning block; 18. Smooth surface pressure block; 19. Positioning key; 20. Stud M10×85; 21. Hexagon flange nut M10; 22. Socket head cap screw M6×16; 23. Hexagon head bolt M10×50; 24. Socket head cap screw M5×16; 25. Socket head cap screw M5×16; 26. Knurled screw M8×35; 27. Socket head cap screw M6×25; 28. Cylindrical pin φ6×25; 29. Socket head cap screw M6×25; 30. Process hole. Detailed implementation method As Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 shown, a method for rough machining the blade body with a small margin of allowance includes: a tooling base assembly 1 (including a baffle 5, a stud 20, and socket head cap screws 24), a flip plate assembly 2 (including a positioning block 3, a support block 4, a support 6, a positioning pin 7, pressure plates 8, 9, and a process table positioning block 17). The tooling base assembly 1 includes a boss positioning surface 11 and a boss side positioning surface 12. There are two groups of positioning keyways 10 on the middle boss surface of the boss positioning surface 11, and positioning surfaces 12 and 13 on the side of the boss. The stud 20 and the hexagon flange nut 21; the flip plate assembly 2 includes upper and lower positioning surfaces 14, 15, a tenon side positioning surface 16 on the basin side, a process table positioning block 17, a positioning pin 7, pressure plates 8, 9, a support 6, an exhaust edge tenon side positioning block 3, an inlet edge tenon side support block 4, a smooth surface pressure block 18, 4 positioning keys 19 in the middle of the flip plate, socket head cap screws 22, 24, 25, 27, 29, a cylindrical pin 28, a hexagon head bolt 23, a process hole 30, etc. The part is fixed on the process table side of the flip plate 2 with a process table positioning block 17, a positioning pin 7, a pressure plate 8, a support 6, and a hexagon head bolt 23. The tenon side is positioned with the tenon side positioning surface 16 on the flip plate 2. The exhaust edge tenon side is positioned with the positioning block 3. The other side is fixed with a support block 4, a knurled screw 26, and a smooth surface pressure block 18. The back side is fixed with a pressure plate 9, a support 6, and a hexagon head bolt 23. Finally, the flip plate 2 and the base 1 are positioned with a positioning key 19 and a baffle 5 and fixed with a nut 21, so that the large area of the blade profile is close to a plane, which is convenient for machining with a three-axis machining center.

[0017] The described tooling base assembly 1 is composed of a bottom plate and six bosses. The bottom surface of the boss bottom plate is parallel to the upper end surface 11 of the boss of the base 1, and the parallelism is not greater than 0.01 mm. The six bosses are required to have the same height, and the flatness is not greater than 0.01 mm. When the tooling is clamped, the bottom surface of the bottom plate is placed flat on the workbench and pressed tightly by screws at four U-shaped grooves. The alignment of the reference surface 12 of the base is not greater than 0.02 mm. Four studs 20 are connected and locked with the bosses, and the baffle 5 is connected to the base 1 with screws 24.

[0018] As Figure 2 shown, on the tenon side of the described turning plate assembly 2, the positioning block 3 is positioned and fixed on the turning plate 2 with 2 screws 29 (M6×25) and 2 cylindrical pins 28 (φ6×32). The contact surface of the positioning block 3 is perpendicular to the positioning surface 16 on the tenon basin side of the turning plate 2, and the perpendicularity is not greater than 0.01 mm. The longitudinal angle with the positioning surface 14 on the turning plate 2 ensures the dimension of 18°±0.5°. The support block 4 is fixed on the turning plate with 2 screws 25 (M5×16) and assembled with the knurled screw 26 and the smooth surface pressing block 18. The support 6 is assembled between the pressing plate 9 and the turning plate 2 to play a supporting role. After assembly, the contact surface of the pressing plate 9 is required to be parallel to the positioning surface 16 on the tenon basin side of the turning plate 2.

[0019] On the process table side of the described turning plate assembly 2, the process table positioning block 17 is positioned and fixed with 4 hexagon socket head cap screws 27 (M6×25) and 2 cylindrical pins 28 (φ6×32). The positioning pin 7 is assembled with the process table positioning block 17. After assembly, the transverse angle between the positioning surface of the process table positioning block 17 and the positioning surface 14 of the turning plate ensures the dimension of 18°±0.5°. The perpendicularity of the pin to the positioning surface is not greater than 0.01 mm. Then the pressing plate 8 is connected with hexagon head bolts 23 (M10×50), and the support 6 is assembled between the pressing plate 8 and the turning plate 2 to play a supporting role. The pressing surface of the pressing plate is required to be parallel to the positioning surface of the process table positioning block 17.

[0020] After the described turning plate assembly 2 is assembled, it is required that the positioning surface 16 on the tenon basin side is parallel to the positioning surface of the process table positioning block 17, and the parallelism is not greater than 0.01 mm. The step difference dimension between the two positioning surfaces is ensured to be 9.8±0.01 mm. The center of the positioning pin 7 and the contact surface between the tenon exhaust side positioning block 3 and the part ensure the dimension of 37.045±0.01 mm.

[0021] When the described turning plate positioning surface 14 and positioning surface 15 are processed, the parallelism between them is required to be not greater than 0.01 mm, and the perpendicularity to the side positioning surface is not greater than 0.015 mm.

[0022] As Figure 3As shown, parts such as the base assembly 1, the flip plate assembly 2, the process table positioning block 17, the pressure plate 8, and the pressure plate 9 are made of 45 steel and all need to go through a heat treatment process. The heat treatment hardness shall not be lower than HRC35. Among them, the positioning block 3 and the positioning pin 7 are made of CrWMn and the heat treatment hardness shall not be lower than HRC55. The roughness of the upper and lower positioning surfaces of the flip plate 2 reaches Ra0.8, and the roughness of the upper and lower positioning surfaces of the base 1 is also required to reach Ra0.8.

[0023] As Figure 4 , Figure 5 , Figure 6 shown, the installation sequence of this tooling is as follows: When loading and unloading parts, open the pressure plates 8 and 9, clamp the blade basin side downward. The blade process hole has a clearance fit with the positioning pin 7. The blade process table basin side positioning surface is closely attached to the positioning surface of the process table positioning block 17 and is detected with a 0.02 mm feeler gauge. The blade tenon exhaust side reference surface is closely attached to the positioning surface of the process table 3 and is detected with a 0.02 mm feeler gauge. The blade basin side tenon positioning surface is closely attached to the flip plate basin side positioning surface 16 and is detected with a 0.02 mm feeler gauge. Gently lock the pressure plates 8 and 9 with bolts 23. After rotating the knurled screw 26 to drive the smooth surface pressing block 18 to tightly press the blade tenon intake side, tighten the bolts 23. Install the flip plate assembly 2 with the installed parts and the base 1. During installation, the process table is on the left side of the machine tool worktable, place the blade back upward. The positioning key 19 is fitted with the positioning key grooves 10 on the two middle bosses of the base 1. The side surface of the flip plate 2 is closely attached to the baffle 5. The positioning surface 15 of the flip plate 2 is closely attached to the six bosses of the base 1. The clearance at the above-mentioned joint surfaces is detected with a 0.02 mm feeler gauge respectively. After confirming that the above clearances meet the requirements, tighten the nut 21. When machining the blade basin side, flip the flip frame 2 back and forth and repeat the installation and inspection process with the base 1.

Claims

1. A method for rough machining a blade body with a small residual blade, characterized in that: at least include: Tooling base assembly, flip plate assembly, the tooling base assembly includes a baffle, studs, hexagon socket screws, boss positioning surface and boss side positioning surface, the flip plate assembly includes a positioning block, a support block, a support, a positioning pin, a pressure plate, a pressure plate, a process table positioning block, there are two sets of positioning keyways on the middle boss surface of the boss positioning surface, there are positioning surfaces and positioning surfaces on the side of the boss, studs, hexagonal flange nuts; the flip plate assembly includes upper and lower positioning surfaces and tenon basin side positioning surfaces, process table positioning blocks, positioning pins, pressure plates, supports, exhaust side tenon side positioning blocks, intake side tenons The head side support block, smooth pressure block, positioning key in the middle of the flip plate, hexagon socket screw, cylindrical pin, hexagon bolt, process hole, the parts are fixed on the process table side of the flip plate with the process table positioning block, positioning pin, pressure plate, support, hexagon bolt, the tenon side is positioned with the tenon basin side positioning surface on the flip plate, and the tenon exhaust side is positioned with the positioning block, the other side is fixed with the support block, knurled screw, smooth pressure block, the back side is fixed with the pressure plate, support, hexagon bolt, and finally the flip plate and the base are positioned with the positioning key and baffle and fixed with nuts, so that the blade profile is in contact with the plane over a large area. Close, convenient for processing with a three-axis machining center; the installation sequence of this tooling is as follows: when loading and unloading parts, open the pressure plate and the pressure plate, clamp the blade basin side downward, the blade process hole and the positioning pin clearance match, the blade process table basin side positioning surface and the process table positioning block positioning surface are tightly attached and checked with a 0.02mm feeler gauge, the blade tenon exhaust side reference surface and the process table positioning surface are tightly attached and checked with a 0.02mm feeler gauge, the blade basin side tenon positioning surface and the flip plate basin side positioning surface are tightly attached and checked with a 0.02mm feeler gauge, the pressure plate and the pressure plate are gently tightened with bolts, and the knurling is turned. After the screw drives the smooth pressure block to tighten the air inlet edge of the blade tenon, tighten the bolts and install the flip plate assembly with the installed parts to the base. During installation, the process table is on the left side of the machine tool workbench, and the blade is placed with the back facing up. The locating key cooperates with the locating key slots on the two middle bosses of the base, the side of the flip plate is tightly attached to the baffle, and the locating surface of the flip plate is tightly attached to the six bosses of the base. Use a 0.02mm feeler gauge to check the gap at the tight places of the above-mentioned joint surfaces. After confirming that the above-mentioned gap meets the requirements, tighten the nut. When processing the blade basin side, turn the flip frame back and forth and repeat the installation and inspection process with the base.

2. The method for rough machining a blade body with a small residual blade according to claim 1, characterized in that: The tooling base assembly includes a boss base plate and six bosses. The bottom surface of the boss base plate is parallel to the upper end surface of the base boss with a parallelism of no more than 0.01 mm. The six bosses are required to be of the same height with a flatness of no more than 0.01 mm. When the tooling is clamped, the bottom surface of the base plate is placed flat on the workbench and the four U-shaped grooves are tightened with screws. The base reference surface is aligned to be no more than 0.02 mm. A total of 4 studs are connected and locked to the boss, and the baffle is connected to the base with screws.

3. The method for rough machining a blade body with a small residual blade according to claim 1, characterized in that: The tenon side of the flip plate assembly is positioned and fixed by a positioning block on the flip plate with 2 screws and 2 cylindrical pins, the contact surface of the positioning block and the positioning surface on the tenon basin side of the flip plate are perpendicular to each other, the verticality is not more than 0.01mm, and the longitudinal angle with the positioning surface on the flip plate is guaranteed to be 18°±0.5°, the support block is fixed on the flip plate with 2 screws and assembled with the knurled screws and the smooth pressure block, and the support is assembled between the pressure plate and the flip plate to play a supporting role. After assembly, the contact surface of the pressure plate and the positioning surface on the tenon basin side of the flip plate are required to be parallel to each other.

4. The method for rough machining a blade body with a small residual blade according to claim 1, characterized in that: The process table side of the flip plate assembly is positioned and fixed by the process table positioning block, 4 hexagonal screws and 2 cylindrical pins. The positioning pin is assembled with the process table positioning block. After assembly, the lateral angle between the positioning surface of the process table positioning block and the positioning surface of the flip plate is guaranteed to be 18°±0.5°, and the verticality between the pin and the positioning surface is not more than 0.01mm. Then the pressure plate is connected with hexagonal bolts and supported between the pressure plate and the flip plate for support. The clamping surface of the pressure plate is required to be parallel to the positioning surface of the process table positioning block.

5. The method for rough machining a blade body with a small residual blade according to claim 1, characterized in that: The tenon basin side positioning surface of the flip plate assembly remains parallel to the positioning surface of the process table positioning block, with a parallelism of no more than 0.01mm, ensuring that the step difference between the two positioning surfaces is 9.8±0.01mm, and the contact surface between the positioning pin center and the tenon exhaust side positioning block and the part is ensured to be 37.045±0.01mm.

6. The method for rough machining a blade body with a small residual blade according to claim 1, characterized in that: The positioning surfaces of the flip plate and the positioning surfaces are required to be parallel to each other no more than 0.01 mm and perpendicular to the side positioning surfaces no more than 0.015 mm during processing.

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