A deformation prevention machining method for a special complex thin-walled part

Abstract

The present application relates to the technical field of thin-walled part processing, and discloses a deformation prevention processing method for a special-shaped complex thin-walled part, which comprises an ejection seat, a special-shaped workpiece is welded to the bottom of the ejection seat, a special-shaped die is arranged in the special-shaped workpiece, a positioning plate is detachably installed on the top of the special-shaped die through bolts, ejection screw holes are formed on the surface of the positioning plate on both sides, a flow channel groove is formed on the outer wall of the special-shaped workpiece, and a pouring hole is formed in the inner bottom wall of the special-shaped die. The uniformly distributed ejection screw hole is designed, the ejection screw rod is threadedly connected in the ejection screw hole, and the rotation of the ejection screw rod downwardly separates the special-shaped die and the special-shaped workpiece and ensures uniform stress, thereby preventing product deformation in the removal process. The processing deformation problem of the 3mm-level ultra-thin-walled special-shaped complex curved surface part is solved, the overall deformation of the casting is controlled within ±0.3mm, and the machining precision of the casting is ensured.

Description

Technical Field

[0001] This invention relates to the field of thin-walled parts processing technology, and specifically to a deformation-resistant processing method for irregularly shaped and complex thin-walled parts. Background Technology

[0002] Irregularly shaped, complex thin-walled parts (asymmetrical workpieces with complex shapes and wall thicknesses not exceeding 5 mm, also referred to as thin-walled parts in this invention) have the characteristics of being lightweight and having a single side, and have been widely used in many fields such as mold making and aerospace.

[0003] Currently, machining methods for complex, thin-walled parts include cutting, precision milling, and welding. Before machining, the thin-walled parts need to be clamped. However, due to their relatively low rigidity and large machining allowances, the balance and magnitude of the clamping force at different clamping points on the surface of the thin-walled part are particularly important. From the perspective of clamping force, excessive force will cause deformation of the thin-walled part, while insufficient force will result in insufficient clamping, causing vibration during machining and affecting the machining accuracy. More importantly, for existing machining methods for 3mm-level thin-walled parts, it is difficult to guarantee that machining deformation is within ±0.5mm using conventional anti-deformation control methods, leading to out-of-tolerance machining results. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for preventing deformation in the processing of irregularly shaped, complex, thin-walled parts.

[0005] The present invention provides the following technical solution: a method for preventing deformation of irregularly shaped, complex, thin-walled parts, which employs a deformation-preventing tool with a specific structure. The deformation-preventing tool includes an ejector seat, an irregularly shaped workpiece welded to the bottom of the ejector seat, an irregularly shaped mold disposed inside the irregularly shaped workpiece, a positioning plate detachably mounted on the top of the irregularly shaped mold by bolts, ejector screw holes on both sides of the surface of the positioning plate, a flow channel groove on the outer wall of the irregularly shaped mold, and an filling hole on the inner bottom wall of the irregularly shaped mold.

[0006] See Figure 1-3 The steps of the anti-deformation processing method include: Step 1, Install the tooling: Heat the irregular mold to 60°C in an oven, then insert it into the inner cavity of the irregular workpiece, ensuring verticality, until the bottom of the irregular workpiece reaches the installation position line; Step 2, filling with paraffin wax: Heat the paraffin wax to a molten state and pour it into the irregular mold through the filling hole to fill the assembly gap of the irregular mold. After filling, check the unfilled areas and add paraffin wax through the runner until it is completely filled. Then cool the tooling to room temperature. Step 3, Machining: Using the positioning plate, install the irregular mold and irregular workpiece onto the machining plane of the machine tool machining center, and perform machining based on the reference. Step 4, Stress Relief by Heating: Place the irregular mold and the irregular workpiece together in an aging furnace and heat them. Through a stepped heating process, remove the paraffin wax and relieve stress. Heating process: 50℃×0.5h→80℃×0.5h→100℃×0.5h→120℃×0.5h→150℃×4h. Step 5, Remove tooling: Insert the ejector screw into the ejector screw hole of the positioning plate, and eject the six ejector bolts evenly. After removing the irregular mold, clean the paraffin wax from the surface of the irregular workpiece and the irregular mold.

[0007] Preferably, during the paraffin filling step, the irregular mold and the irregular workpiece are arranged in an inverted position.

[0008] The further optimized anti-deformation tool is also equipped with a filling and ejection auxiliary mechanism, including a base, a slide rod fixedly installed on the top of the base, a limit nut one threadedly connected to the middle section of the outer side of the slide rod, a sliding sleeve fitted on the middle section of the outer side of the slide rod, a crossbar fixedly installed between the two sliding sleeves, a pressing component provided at the middle end of the outer side of the crossbar, a limit nut two threadedly connected to the top of the outer side of the slide rod, and an ejection seat fitted above the limit nut two on the outer side of the slide rod.

[0009] Preferably, the surface of the sliding sleeve is provided with a positioning nut, and the internal thread of the positioning nut is connected to a positioning bolt. The sliding sleeve is locked to the sliding rod by the positioning nut and the positioning bolt.

[0010] Preferably, the pressing assembly includes a large drive arm, the bottom of which is movably mounted to a crossbar via a movable ring. A limiting ring for restricting the movable ring is fixedly mounted on the outer side of the crossbar. A small drive arm is movably mounted on the top of the large drive arm via a hinge shaft one. A torsion spring one is fitted on both outer ends of the hinge shaft one. A pressure head is movably mounted on the top of the small drive arm via a hinge shaft two. A torsion spring two is movably mounted on both outer ends of the hinge shaft two. A pneumatic rod is movably mounted between the hinge shaft two and the crossbar via a fixed ring.

[0011] Preferably, a handle is fixedly installed on the top of the pressure head, a limiting protrusion is fixedly installed on the bottom of the pressure head, the limiting protrusion presses against the side of the ejector seat, extension plates are fixedly installed on both sides of the pressure head, the extension plates press against the surface of the ejector seat, a pressure ring is fixedly installed at the end of the extension plate, the pressure ring is fitted on the upper side of the slide rod and presses against the surface of the ejector seat.

[0012] Preferably, the large drive arm has an internal mounting groove, the opening of the mounting groove is fitted with a sealing ring, a T-shaped clamp is inserted inside the sealing ring, a push spring is provided on the side of the T-shaped clamp, and the outer side of the crossbar has a corresponding and circularly arranged slot, and the large drive arm is rotatably engaged with the crossbar through the T-shaped clamp and the slot.

[0013] Compared with the prior art, the present invention has the following beneficial effects: This method for preventing deformation in the processing of complex, thin-walled, irregularly shaped parts utilizes a conformal internal cavity to provide support during processing. The outer surface of the irregular mold is designed with paraffin wax flow channels, and paraffin wax inlet holes are designed inside the mold. Before processing, liquid high-strength paraffin wax is filled through these holes and flow channels to fill the gaps between the tooling and the product, ensuring zero gap between them and strengthening the tooling's support. After the paraffin wax cools and solidifies, the outer surface is processed. A stepped heating and cooling stress-relief aging method is employed. During the heating and removal of paraffin wax, stepped temperature control prevents casting deformation caused by paraffin wax expansion. Simultaneously, stress-relief annealing is performed on the product to prevent springback deformation of the irregular workpiece after removal of the mold. A uniformly distributed ejector screw hole is used, through which the ejector screw is threaded. Rotating the ejector screw downwards separates the irregular mold and the workpiece, ensuring uniform force distribution and preventing product deformation during removal. This invention solves the problem of machining deformation of 3mm-level ultra-thin-walled irregular and complex curved surface parts, and can control the overall deformation of the casting within ±0.3mm, ensuring the machining accuracy of the casting; This anti-deformation processing method for complex thin-walled parts involves installing the ejector seat on the limiting nut two of the slide rod during paraffin filling and ejection separation. The pressure head is then pulled out using the handle, extending the large drive arm, small drive arm, and pneumatic rod. The pressure head and extension plate are then pressed against the top of the ejector seat, while the limiting protrusion presses against the side of the ejector seat. The pressure ring is fitted onto the slide rod. Then, torsion spring two controls the pressure head to press down tightly, while torsion spring one controls the small drive arm and large drive arm to retract. The pneumatic rod also retracts, thus fixing the ejector seat, the irregularly shaped workpiece, and the irregularly shaped mold in place, facilitating subsequent paraffin filling and disassembly separation. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the inverted three-dimensional arrangement of the irregularly shaped workpiece and the irregularly shaped mold in Example 1. Figure 2 This is a schematic diagram of the irregularly shaped mold in Example 1; Figure 3 This is a bottom view schematic diagram of the irregular mold in Example 1; Figure 4 This is a schematic diagram of the installation structure of the filling and ejection auxiliary mechanism and the irregularly shaped workpiece in Example 2; Figure 5 This is a schematic diagram of the ejector seat and the filling and ejection auxiliary mechanism in Example 2; Figure 6 This is a partial structural diagram of the slide bar and pressing assembly in Example 2; Figure 7 This is an exploded view of the pressing component in Example 2; Figure 8 This is a side view of the pressing component in Example 2; Figure 9 This is an exploded structural diagram of the crossbar, large drive arm, and T-shaped clamp in Example 2; Figure 10 This is a bottom view of the pressure head structure in Example 2; Figure 11 This is a schematic diagram of the planar cross-sectional structure of the push spring, T-shaped clamp, and crossbar in Example 2.

[0015] In the diagram: 1. Base; 2. Slide rod; 3. Limiting nut one; 4. Sliding sleeve; 5. Crossbar; 6. Pressing assembly; 7. Limiting nut two; 8. Ejector seat; 9. Irregularly shaped workpiece; 10. Irregularly shaped mold; 11. Positioning plate; 12. Ejector screw hole; 13. Flow channel; 14. Filling hole; 15. Positioning nut; 16. Positioning bolt; 61. Large drive arm; 62. Movable ring; 63. Limiting ring; 64. Hinge shaft one; 65. Small drive arm; 66. Torsion spring one; 67. Hinge shaft two; 68. Press head; 69. Torsion spring two; 610. Fixed ring; 611. Pneumatic rod; 612. Handle; 613. Limiting protrusion; 614. Extension plate; 615. Pressure ring; 616. Mounting groove; 617. Sealing ring; 618. T-shaped clamp; 619. Push spring; 620. Slot. Detailed Implementation

[0016] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] A certain irregularly shaped, complex thin-walled part, such as Figure 1 As shown, it has a structure that is thinner at the top and thicker at the bottom, and the top of the irregularly shaped and complex thin-walled part has a beveled edge and a pointed part. The angle between the beveled edge and the horizontal plane is not less than 25°, and the wall thickness is 3-5mm (the wall thickness varies in different parts). The parts of the irregularly shaped and complex thin-walled part that are most prone to deformation during the forming process are the root of the side wall and the position of the beveled edge.

[0018] Example 1, see Figure 1-3A method for preventing deformation of complex thin-walled parts with irregular shapes is disclosed. The method employs a deformation-preventing tool with a specific structure. The deformation-preventing tool includes an ejector seat 8, with an irregular workpiece 9 welded to the bottom of the ejector seat 8. An irregular mold 10 is provided inside the irregular workpiece 9. A positioning plate 11 is detachably installed on the top of the irregular mold 10 by bolts. Ejection screw holes 12 are provided on both sides of the surface of the positioning plate 11. A flow channel groove 13 is provided on the outer wall of the irregular mold 10, and an injection hole 14 is provided on the inner bottom wall of the irregular mold 10.

[0019] See Figure 1-3 The steps of the anti-deformation processing method include: Step 1, Install the tooling: After heating the irregular mold 10 to 60°C in an oven, insert it into the inner cavity of the irregular workpiece 9, ensuring verticality, until the bottom of the irregular workpiece 9 reaches the installation position line; Step 2, filling with paraffin wax: Heat the paraffin wax to a molten state and pour it into the irregular mold 10 through the filling hole 14 to fill the assembly gap of the irregular mold 10. After filling, check the unfilled areas and add paraffin wax through the flow channel 13 until it is completely filled. Then cool the tooling to room temperature. When filling with paraffin wax, the irregular mold 10 and the irregular workpiece are set up at an inverted angle. Step 3, Machining: Using the positioning plate 11, install the irregular mold 10 and the irregular workpiece 9 onto the machining plane of the machine tool machining center, and perform machining based on the reference. Step 4, Stress Relief by Heating: Place the irregular mold 10 and the irregular workpiece 9 together in an aging furnace for heating. Through a stepped heating process, remove the paraffin wax and relieve stress. Heating process: 50℃×0.5h→80℃×0.5h→100℃×0.5h→120℃×0.5h→150℃×4h; Step 5, Remove tooling: Insert the ejector screw into the ejector screw hole 12 of the positioning plate 11, and eject the six ejector bolts evenly. After removing the irregular mold 10, clean the paraffin wax from the surface of the irregular workpiece 9 and the irregular mold 10.

[0020] In this embodiment, the irregular mold 10 provides processing support through the conformal inner cavity. The outer surface of the irregular mold 10 is designed with a paraffin wax flow channel 13, and the interior of the irregular mold 10 is designed with a paraffin wax injection hole 14. Before processing, liquid high-strength paraffin wax is filled through the injection hole 14 and the flow channel 13 to fill the gap between the tooling and the product, ensuring zero gap between the tooling and the product, and strengthening the supporting role of the tooling. After the paraffin wax cools and solidifies, the outer surface is processed. In this embodiment, a stepped heating and cooling stress-relieving aging method is adopted. During the process of heating and removing paraffin wax, the temperature is controlled in a stepped manner to prevent the deformation of the casting caused by the expansion of paraffin wax. At the same time, the product is subjected to stress-relieving annealing to prevent the springback deformation of the irregular workpiece 9 after the irregular mold 10 is removed. In this embodiment, evenly distributed ejector screw holes are used to thread the ejector screw into them. Rotating the ejector screw downwards separates the irregular mold and the irregular workpiece, ensuring uniform force and preventing product deformation during removal. Together with other operating steps, this solves the processing deformation problem of 3mm-level ultra-thin-walled irregular complex curved surface parts. It can control the overall deformation of the casting within ±0.3mm, the deformation at the root of the side wall of the irregular complex thin-walled part within ±0.3mm, and the deformation at the oblique edge position within ±0.2mm, ensuring the processing accuracy of the casting.

[0021] Example 2: See Figure 4-5 A method for preventing deformation of irregularly shaped, complex, thin-walled parts is further optimized based on Embodiment 1. The anti-deformation tool is also equipped with a filling and ejection auxiliary mechanism, including a base 1, a slide rod 2 fixedly installed on the top of the base 1, a limit nut 3 threadedly connected to the middle section of the outer side of the slide rod 2, a sliding sleeve 4 fitted on the middle section of the outer side of the slide rod 2, a crossbar 5 fixedly installed between the two sliding sleeves 4, a pressing component 6 provided at the middle end of the outer side of the crossbar 5, a limit nut 7 threadedly connected to the top of the outer side of the slide rod 2, and an ejector seat 8 fitted above the limit nut 7 on the outer side of the slide rod 2.

[0022] See Figure 6-7 The sliding sleeve 4 is fitted with a positioning nut 15, and the internal thread of the positioning nut 15 is connected to a positioning bolt 16. The sliding sleeve 4 is locked to the sliding rod 2 by the positioning nut 15 and the positioning bolt 16, which can adjust the height of the entire pressing assembly 6.

[0023] See Figure 6-8 The pressing assembly 6 includes a large drive arm 61, which is H-shaped. The bottom of the large drive arm 61 is movably mounted to the crossbar 5 via a movable ring 62. A limiting ring 63 for restricting the movable ring 62 is fixedly mounted on the outside of the crossbar 5. A small drive arm 65 is movably mounted on the top of the large drive arm 61 via a hinge pin 64. The small drive arm 65 is H-shaped. Torsion springs 66 are fitted on both ends of the hinge pin 64. The torsion springs 66 can control the large drive arm 61 and the small drive arm 65 to move closer together. A pressing head 68 is movably mounted on the top of the small drive arm 65 via a hinge pin 67. Torsion springs 69 are movably mounted on both ends of the hinge pin 67. The torsion springs 69 can control the pressing head 68 and the small drive arm 65 to move closer together. A pneumatic rod 611 is movably mounted between the hinge pin 67 and the crossbar 5 via a fixing ring 610. The angle between the large drive arm 61 and the small drive arm 65 can be controlled by the pneumatic rod 611.

[0024] See Figure 8-10A handle 612 is fixedly installed on the top of the pressure head 68, and a limiting protrusion 613 is fixedly installed on the bottom of the pressure head 68. The limiting protrusion 613 presses against the side of the ejector seat 8. Extension plates 614 are fixedly installed on both sides of the pressure head 68. The extension plates 614 press against the surface of the ejector seat 8. A pressure ring 615 is fixedly installed at the end of the extension plate 614. The pressure ring 615 is fitted on the upper side of the slide rod 2 and presses against the surface of the ejector seat 8.

[0025] See Figure 9-11 The large drive arm 61 has an internal mounting groove 616, and a sealing ring 617 is embedded in the opening of the mounting groove 616. A T-shaped clip 618 is inserted inside the sealing ring 617. A push spring 619 is provided on the side of the T-shaped clip 618. The outer side of the crossbar 5 has a ring-shaped slot 620 corresponding to the T-shaped clip 618. The large drive arm 61 is rotatably engaged with the crossbar 5 through the T-shaped clip 618 and the slot 620 to ensure that the large drive arm 61 can be locked after rotation and to ensure that the large drive arm 61 will not loosen due to rotation.

[0026] During the anti-deformation processing, when filling with paraffin wax and separating from the ejector, the ejector seat 8 is installed on the limiting nut 7 of the slide bar 2. The pressure head 612 is pulled up and unfolded by the handle, in which the large drive arm 61, the small drive arm 65 and the pneumatic rod 611 will expand. Then the pressure head 612 and the extension plate 614 are pressed against the top of the ejector seat 8, the limiting protrusion 613 is pressed against the side of the ejector seat 8, and the pressure ring 615 is fitted onto the slide bar 2. Then the second torsion spring 69 controls the pressure head 68 to press down tightly, and the first torsion spring 66 controls the small drive arm 65 and the large drive arm 61 to retract towards each other. Then the pneumatic rod 611 will also retract. In this way, the pressure head 68 will fix the ejector seat 8, the irregular workpiece 9 and the irregular mold 10, which will facilitate the subsequent filling with paraffin wax and disassembly and separation.

Claims

1. A method for preventing deformation during machining of irregularly shaped, complex, thin-walled parts, employing an anti-deformation tool, the anti-deformation tool including an ejector seat (8), characterized in that, The bottom of the ejector seat (8) is welded with an irregular workpiece (9), and an irregular mold (10) is provided inside the irregular workpiece (9). A positioning plate (11) is detachably installed on the top of the irregular mold (10) by bolts. Ejection screw holes (12) are provided on both sides of the surface of the positioning plate (11). A flow channel groove (13) is provided on the outer wall of the irregular mold (10), and an injection hole (14) is provided on the inner bottom wall of the irregular mold (10). The steps of the anti-deformation processing method include: Step 1, Install the tooling: Heat the irregular mold (10) to 60°C in an oven and then insert it into the inner cavity of the irregular workpiece (9), ensuring the verticality of the installation until the bottom of the irregular workpiece (9) reaches the installation position line; Step 2, filling with paraffin wax: Heat the paraffin wax to a molten state and fill it into the irregular mold (10) through the filling hole (14) to fill the assembly gap of the irregular mold (10). After filling, check the unfilled positions and add paraffin wax through the flow channel (13) until it is completely filled. Then cool the tooling to room temperature. Step 3, machining: Using the positioning plate (11), install the irregular mold (10) and the irregular workpiece (9) onto the machining plane of the machine tool machining center, and find the reference for machining; Step 4, stress relief by heating: The irregular mold (10) and the irregular workpiece (9) are placed together in the aging furnace and heated. The paraffin wax is removed and the stress is relieved by a stepped heating process. Heating process: 50℃×0.5h→80℃×0.5h→100℃×0.5h→120℃×0.5h→150℃×4h; Step 5, remove tooling: Insert the ejector screw into the ejector screw hole (12) of the positioning plate (11), and eject the six ejector bolts evenly. After removing the irregular mold (10), clean the paraffin wax from the surface of the irregular workpiece (9) and the irregular mold (10).

2. The anti-deformation processing method for irregularly shaped, complex, thin-walled parts according to claim 1, characterized in that: When filling the paraffin wax in step 2, the irregular mold (10) and the irregular workpiece (9) are set up in an inverted position.

3. The anti-deformation processing method for irregularly shaped, complex, thin-walled parts according to claim 2, characterized in that: The anti-deformation tool is also equipped with a filling and ejection auxiliary mechanism, including a base (1), a slide rod (2) is fixedly installed on the top of the base (1), a limit nut (3) is threadedly connected to the middle section of the outer side of the slide rod (2), a sleeve (4) is fitted on the middle section of the outer side of the slide rod (2), a crossbar (5) is fixedly installed between the two sleeves (4), a pressing component (6) is provided on the middle section of the outer side of the crossbar (5), a limit nut (7) is threadedly connected to the top of the outer side of the slide rod (2), and the ejection seat (8) is fitted on the upper part of the limit nut (7) on the outer side of the slide rod (2).

4. The anti-deformation processing method for irregularly shaped, complex, thin-walled parts according to claim 3, characterized in that: The sliding sleeve (4) is fitted with a positioning nut (15), and the internal thread of the positioning nut (15) is connected to a positioning bolt (16). The sliding sleeve (4) is locked to the sliding rod (2) by the positioning nut (15) and the positioning bolt (16).

5. The anti-deformation processing method for irregularly shaped, complex, thin-walled parts according to claim 3, characterized in that: The pressing assembly (6) includes a large drive arm (61), the bottom of which is movably mounted to a crossbar (5) via a movable ring (62). A limiting ring (63) for limiting the movable ring (62) is fixedly mounted on the outer side of the crossbar (5). A small drive arm (65) is movably mounted on the top of the large drive arm (61) via a hinge shaft (64). A torsion spring (66) is fitted on both ends of the hinge shaft (64). A pressure head (68) is movably mounted on the top of the small drive arm (65) via a hinge shaft (67). A torsion spring (69) is movably mounted on both ends of the hinge shaft (67). A pneumatic rod (611) is movably mounted between the hinge shaft (67) and the crossbar (5) via a fixing ring (610).

6. The anti-deformation processing method for irregularly shaped, complex, thin-walled parts according to claim 5, characterized in that: A handle (612) is fixedly installed on the top of the pressure head (68), and a limiting protrusion (613) is fixedly installed on the bottom of the pressure head (68). The limiting protrusion (613) presses against the side of the ejector seat (8). Extension plates (614) are fixedly installed on both sides of the pressure head (68). The extension plates (614) press against the surface of the ejector seat (8). A pressure ring (615) is fixedly installed at the end of the extension plate (614). The pressure ring (615) is fitted on the upper side of the slide rod (2) and presses against the surface of the ejector seat (8).

7. The anti-deformation processing method for irregularly shaped, complex, thin-walled parts according to claim 5, characterized in that: The large drive arm (61) has an installation groove (616) inside. A sealing ring (617) is embedded in the opening of the installation groove (616). A T-shaped clip (618) is inserted inside the sealing ring (617). A push spring (619) is provided on the side of the T-shaped clip (618). A slot (620) corresponding to the T-shaped clip (618) and arranged in a ring is provided on the outer side of the crossbar (5). The large drive arm (61) is rotated and engaged with the crossbar (5) through the T-shaped clip (618) and the slot (620).

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