A lightweight integral honeycomb structure and electrolytic processing device and method

Abstract

The present invention discloses a lightweight integral honeycomb structure and an electrolytic processing device and method thereof, belonging to the field of electrolytic processing technology. The honeycomb structure bottom plate is integrated with the honeycomb structure, and the honeycomb array hole wall thickness dimensions are inconsistent, and there are structural characteristics of transition fillets at the wall thickness transition positions, which generally achieves the purpose of reducing the weight of the honeycomb wall plate, while ensuring that a certain thickness margin is left at the top of the honeycomb hole wall to provide mechanical support for subsequent processes; the present invention adopts a segmented group hole electrolytic processing process, which can complete the one-time simultaneous electrolytic forming of the honeycomb array holes, and realize high-quality and efficient processing of high-density array special-shaped group holes. Compared with the existing honeycomb sandwich through-hole structure, the present invention greatly improves the mechanical strength of the honeycomb structure and the processing efficiency of the honeycomb holes, reduces the deformation problem of such parts during the processing process, and the final formed integral honeycomb hole structure has higher strength and high practical value.

Description

Technical Field

[0001] The present invention relates to the technical field of electrolytic machining, and in particular to a lightweight integral honeycomb structure and an electrolytic machining device and method. Background Art

[0002] Since the honeycomb structure has good properties such as high strength, light weight, fatigue resistance, easy sound insulation and heat insulation, it is often used in the aerospace industry to make various wall panels for satellite shells, rigid solar cell wings, rocket propellant tanks, etc. At present, the traditional method uses the process of welding thinner surface plates on the upper and lower sides of the honeycomb through-hole sandwich layer to process honeycomb sandwich panels. The process is complicated, the processing efficiency is low, and the structural strength of the formed product is not high. The efficient process method of simplifying the process and improving the structural strength of the formed product is a problem that still needs to be solved in the manufacture of honeycomb panels.

[0003] The most important part of the honeycomb wall panel manufacturing process is the processing of the honeycomb structure. Its processing methods mainly include roll brazing forming, laser additive manufacturing, electrospark machining, electrochemical machining, etc. The roll brazing forming method has complex processing procedures and low processing efficiency. The laser additive manufacturing method uses laser scanning and melting to manufacture powdered materials in layers. This method is suitable for processing parts with complex shapes, but there are many auxiliary processes, low processing efficiency and processing accuracy, and low strength of the formed structure. The electrospark machining method can realize the processing of special-shaped holes in difficult-to-process materials. However, the tool electrode loss is serious, and the structure after processing has defects such as recasting layer, heat-affected zone, and microcracks that need to be processed later. Electrolytic machining is a process method for processing blanks based on the principle of electrochemical dissolution of the anode. It has the advantages of no tool cathode loss, no residual stress, high processing efficiency, and good processing surface quality. It has been widely used in the processing of various complex parts in the field of aerospace manufacturing. However, the array holes of electrolytic machining in my country are mostly microporous structures, shallow diamond grid holes, etc., and the problem of deep blind holes in special-shaped thin-walled arrays remains to be solved. Summary of the invention

[0004] In response to the above problems, the present invention proposes a lightweight integral honeycomb structure and electrolytic processing device and method, which can solve the problems of complex manufacturing process of honeycomb wall panels, low processing efficiency, and low structural strength of formed products, and realize efficient and high-quality processing of thin-walled honeycomb structure wall panels with array distribution and large depth-to-diameter ratio.

[0005] In order to achieve the above technical objectives, the technical solution adopted by the present invention is:

[0006] A lightweight integral honeycomb structure comprises a base plate and honeycomb array holes arranged on the base plate, wherein: the honeycomb array holes are integrally formed with the base plate, and array blind holes are formed by smooth transition with a first fillet, the thickness of the top of the hole wall of the honeycomb array hole is greater than the thickness of the main body of the honeycomb hole wall, and the top of the hole wall and the main body of the honeycomb hole wall are smoothly transitioned with a second fillet.

[0007] In some of the embodiments, the thickness of the top of the cell wall is greater than the thickness of the main body of the honeycomb cell wall.

[0008] In some of the embodiments, the height of the top of the cell wall is much smaller than the height of the main body of the honeycomb cell wall.

[0009] The electrolytic machining device for preparing a lightweight integral honeycomb structure comprises a fixture seat, a sealed cavity, a cathode chuck, a spindle chuck and a tool cathode; the sealed cavity is fixed on the fixture seat; the workpiece is mounted on the fixture seat for positioning and is placed at the bottom of the sealed cavity at the same time, and the cathode chuck is fixedly connected to the spindle chuck; the spindle chuck is provided with a liquid passage cavity, the cathode chuck is provided with an array through hole, each array through hole is clamped with a tool cathode, the spindle chuck can drive the tool cathode to be inserted into the sealed cavity from above and move up and down, the tool cathode is provided with an axial liquid passage channel, a machining blade is provided at the front end of the tool cathode, a liquid outlet hole is opened in the middle or upper part of the sealed cavity, the sealed cavity and the cathode chuck, and the sealed cavity and the workpiece are sealed by a sealing member, the electrolyte can be injected into the sealed cavity through the liquid passage cavity, the array through hole and the axial liquid passage in turn, and the gap between the workpiece and the tool cathode is immersed, and the excess electrolyte can be discharged from the liquid outlet hole, the tool cathode is connected to the negative pole of a power supply, and the workpiece is connected to the positive pole of the power supply.

[0010] In some of the embodiments, the tool cathode is a tubular structure, an inverted cone hole is provided at the bottom of the axial liquid channel, a liquid outlet group hole is provided between the inverted cone hole and the machining edge, and the electrolyte in the axial liquid channel is discharged from the liquid outlet group hole to the sealed cavity.

[0011] In some of the embodiments, the liquid outlet hole group is arranged in a combination of a central single hole, six middle holes and an outer circular array of twelve holes; the cross-section of the machining blade is a regular hexagonal surface, and the six middle holes of the liquid outlet hole group are six angular holes consistent with the angular direction of the machining blade; the outer circular array holes are staggered with the angular six holes.

[0012] In some of the embodiments, the tool cathode sidewall is covered with an insulating sleeve.

[0013] The method for using the electrolytic processing device of the lightweight integral honeycomb structure specifically comprises the following steps:

[0014] Step 1: The workpiece is positioned and mounted on the fixture seat with the bottom plane. During processing, the spindle chuck drives the tool cathode corresponding to the preset honeycomb structure to be synchronously fed in the vertical direction;

[0015] Step 2: Calibrate and level the fixture, connect the tool cathode to the negative pole of the power supply, and connect the workpiece to the positive pole of the power supply;

[0016] Step 3: Adjust the spindle chuck to move downward to enter the tool setting state. When the tool cathode contacts the workpiece, the spindle chuck is immediately raised a distance as the initial machining gap to complete the tool setting.

[0017] Step 4: introducing electrolyte, which flows into the liquid cavity of the spindle chuck, disperses into each tool cathode through the array through holes in the cathode chuck, enters the processing area through the liquid outlet holes at the bottom of the tool cathode, and finally flows out from the liquid outlet hole of the sealed cavity;

[0018] Step 5, in the hole wall top processing stage, the tool cathode is fed downward rapidly in the vertical direction to the processing depth to process the workpiece. The processing depth is adapted to the thickness of the hole wall top. Due to the fast feeding speed, the side processing gap is small, thereby obtaining a larger top wall thickness and forming the hole wall top.

[0019] Step 6. After the processing of the top of the hole wall is completed, it jumps to the stable forming stage to process the honeycomb hole wall body. In this stage, the tool cathode feeding speed is slower than that of the hole wall top processing stage, so that the second fillet is formed at the connection between the hole wall top and the honeycomb hole wall body. At the same time, the tool cathode feeding speed is slow, so that the side processing gap is larger, thereby obtaining a thinner honeycomb hole wall body thickness and forming a honeycomb hole wall body; after the tool cathode continues to feed to the specified processing position, the processing is stopped. At this time, the bottom end of the tool cathode has not penetrated the bottom of the workpiece, and the unpenetrated bottom is the bottom plate. Since the connection between the honeycomb hole wall body and the bottom plate is itself in the processing end position, when the tool cathode stops working, the first fillet is automatically formed, and the spindle chuck moves upward to drive the tool cathode to leave the workpiece to complete the processing of the workpiece.

[0020] Compared with the prior art, the present invention aims at the characteristics of the traditional honeycomb through-hole sandwich layer welding thinner surface plates on the upper and lower sides, which has the characteristics of complex processing technology, low processing efficiency and low structural strength of the formed product. A lightweight integral honeycomb structure with thin-walled honeycomb array holes and a bottom plate is proposed, which simplifies the manufacturing process of the honeycomb structure and greatly improves the processing efficiency. The honeycomb structure has the structural characteristics that the wall thickness of the honeycomb hole wall is inconsistent, and there are transition fillets at the wall thickness transition position. It generally meets the weight reduction requirements of the honeycomb wall plate, and ensures that a certain thickness margin is left at the top of the honeycomb hole wall to provide mechanical support for the subsequent welding surface plate process, reduce the difficulty of honeycomb spot welding positioning, and effectively inhibit the thermal cycle deformation of the honeycomb hole wall during the subsequent welding process; in detail, the transition fillet part similar to the reinforcing rib structure enhances the strength and rigidity of the honeycomb hole wall, can reduce the stress deformation of the honeycomb hole wall during brazing, and the final formed honeycomb wall plate has higher structural strength. The proposed lightweight integral honeycomb structure electrolytic processing method is used for the processing of integral honeycomb wall plates of difficult-to-process materials, and can complete the one-time simultaneous processing and forming of multiple honeycomb array holes, greatly improving the processing efficiency. The processing device used in this process can achieve uniform liquid distribution in the array honeycomb holes, avoiding the short circuit phenomenon of individual cathodes caused by inconsistent flow fields in the electrolytic processing of the group holes. The tool cathode is a tubular structure, and an inverted cone hole is provided near the bottom of the internal liquid passage pipeline, and an array group hole for liquid flow is provided between the inverted cone hole and the processing edge. The group hole adopts a combination arrangement of a central single hole, six holes in the middle and twelve holes in the outer circle array. Among them, the six holes in the middle are six holes in the angle direction consistent with the edge direction of the processing edge, and the outer circle array holes are misaligned with the six holes in the angle direction. This structure can ensure that the honeycomb hole processing area maintains a high electrolyte flow rate, avoid the occurrence of low electrolyte flow rate areas at the edges and corners, and prevent the generation of a large central boss due to the excessive aperture of the liquid outlet hole, which greatly improves the stability of electrolytic processing. After processing, the side wall of the array hole is smooth and the surface quality is good. The present invention improves the structural strength of such parts, reduces the deformation problem of parts during processing, improves the processing accuracy of parts, and has high practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic diagram of the lightweight integral honeycomb structure of the present invention;

[0022] Figure 2 It is a structural schematic diagram of the lightweight integral honeycomb structure electrolytic processing device of the present invention;

[0023] Figure 3 is a schematic structural diagram of the tool cathode of the present invention;

[0024] Figure 4 It is a schematic diagram of the processing of honeycomb cell wall features of the lightweight integral honeycomb structure described in the present invention.

[0025] The reference numbers in the figure are as follows: 1. spindle chuck, 1a. liquid passage cavity, 2. cathode chuck, 2a. array through hole, 3. sealing cavity, 3a. liquid outlet hole, 4. fixture seat, 5. tool cathode, 5a. axial liquid passage, 6. inverted tapered hole, 7. machining edge, 8. liquid outlet hole group, 9. insulating sleeve, 10. workpiece, 11. bottom plate, 12. honeycomb array hole, 12a. top of hole wall, 12b. honeycomb hole wall body, 13. first fillet, 14. second fillet. DETAILED DESCRIPTION

[0026] The embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

[0027] It should be noted that the terms such as "upper", "lower", "left", "right", "front", "back", etc. cited in the invention are only for the convenience of description and are not used to limit the scope of implementation of the present invention. Changes or adjustments in their relative relationships should be regarded as the scope of implementation of the present invention without substantially changing the technical content.

[0028] The lightweight integral honeycomb structure of the present invention is shown in the schematic diagram as follows: Figure 1 As shown in the figure. The cross section of the honeycomb structure is a densely distributed array of multiple rows of regular hexagons, with each honeycomb cell separated by a thin wall; the thin-wall honeycomb array holes are integrated with the bottom plate, and the formed structure is an integral honeycomb wall plate. Figure 1 As shown, it includes a schematic diagram of a thin-walled characteristic longitudinal section of a honeycomb structure, the honeycomb cell wall structure has a structural feature of inconsistent formed wall thickness, the top of the honeycomb cell wall structure is thickened, the top of the honeycomb cell wall structure and the main body of the honeycomb cell wall structure smoothly transition with a second fillet 14, and the main body of the honeycomb cell wall structure and the bottom plate smoothly transition with a first fillet 13. Among them, the height of the honeycomb overall structure is h, the height h1 of the top of the honeycomb cell wall structure is much smaller than the height h2 of the main body of the honeycomb cell wall, and the thickness h3 of the bottom plate is 0.9-1.2 mm; the thickness d1 of the top of the honeycomb cell wall is greater than the thickness d2 of the main body of the honeycomb cell wall, and the thickness d2 of the main body of the honeycomb cell wall is 0.2-0.3 mm.

[0029] The lightweight integral honeycomb structure electrolytic machining process of the present invention has a schematic diagram of the machining device structure as shown in FIG. Figure 2 As shown. The processing device includes a spindle chuck 1, a cathode chuck 2, a sealed cavity 3, a fixture seat 4 and a tool cathode 5; the fixture seat 4 is fixedly connected to the sealed cavity 3, and the cathode chuck 2 is fixedly connected to the spindle chuck 1; the sealed cavity 3 and the cathode chuck 2, and the sealed cavity 3 and the workpiece blank are sealed by a seal; the tool cathode 5 is clamped on the cathode chuck 2 through an array of through holes for dispersed liquid flow. Figure 3As shown, the tool cathode 5 is a tubular structure, and an inverted cone hole 6 is provided near the bottom of the internal liquid passage, and an array group of holes for liquid passage is provided between the inverted cone hole 6 and the processing edge 7. The liquid outlet group hole 8 adopts a combination of a central single hole, six holes in the middle, and twelve holes in an outer circle array. Among them, the six holes in the middle are six angular holes that are consistent with the angular direction of the processing edge 7, and the outer circle array holes are offset and correspond to the six angular holes. This structure can ensure that the honeycomb hole processing area maintains a high electrolyte flow rate, avoid the occurrence of low electrolyte flow rate areas at the edges and corners, and at the same time prevent the formation of a large central boss due to the excessive aperture of the liquid outlet hole, which greatly improves the stability of electrolytic processing.

[0030] The method for using the electrolytic processing device of the lightweight integral honeycomb structure specifically comprises the following steps:

[0031] Step 1: The workpiece 10 is positioned and mounted on the fixture seat 4 with the bottom plane. During processing, the spindle chuck 1 drives the tool cathode 5 corresponding to the preset honeycomb structure to be synchronously fed in the vertical direction;

[0032] Step 2: Calibrate and level the fixture, connect the tool cathode 5 to the negative pole of the power supply, and connect the workpiece 10 to the positive pole of the power supply;

[0033] Step 3: Adjust the spindle chuck 1 to move downward to enter the tool setting state. When the tool cathode 5 contacts the workpiece 10, the spindle chuck 1 is immediately raised a distance as the initial machining gap to complete the tool setting.

[0034] Step 4: introducing electrolyte, the electrolyte flows into the liquid passage cavity 1a of the spindle chuck 1, disperses into each tool cathode 5 through the array through holes 2a in the cathode chuck 2, enters the processing area through the liquid outlet group holes 8 at the bottom of the tool cathode 5, and finally flows out from the liquid outlet hole 3a of the sealed cavity 3;

[0035] Step 5, in the hole wall top processing stage, the tool cathode 5 is fed downward in the vertical direction to a processing depth quickly to process the workpiece 10. The processing depth is adapted to the thickness of the hole wall top 12a. Due to the fast feeding speed, the side processing gap is small, thereby obtaining a larger top wall thickness and forming the hole wall top 12a.

[0036] Step 6: After the processing of the top of the hole wall is completed, it jumps to the stable forming stage to process the honeycomb hole wall body 12b. In this stage, the feeding speed of the tool cathode 5 is slower than that of the hole wall top processing stage, so that the second fillet 14 is formed at the connection between the hole wall top 12a and the honeycomb hole wall body 12b. At the same time, the feeding speed of the tool cathode 5 is slow, so that the side processing gap is larger, thereby obtaining a thinner honeycomb hole wall body thickness to form a honeycomb hole wall body 12b; after the tool cathode 5 continues to feed to the specified processing position, the processing is stopped. At this time, the bottom end of the tool cathode 5 has not penetrated the bottom of the workpiece 10, and the unpenetrated bottom is the bottom plate 11. Since the connection between the honeycomb hole wall body 12b and the bottom plate 11 is itself in the processing end position, when the tool cathode 5 stops working, the first fillet 13 is automatically formed, and the spindle chuck 1 moves upward to drive the tool cathode 5 to leave the workpiece 10, completing the processing of the workpiece.

[0037] The electrolytic machining process based on a lightweight integral honeycomb structure described in the present invention has the following characteristics: an array distribution cathode corresponding to the honeycomb structure is adopted, and the processing is rapidly fed in the vertical direction, so that multiple honeycomb array holes can be processed and formed at one time, and the formed holes have good consistency and also greatly improve the efficiency of electrolytic machining. Aiming at the structural characteristics that the wall thickness of the honeycomb hole wall structure is inconsistent, and there are transition fillets at the wall thickness transition position, the processing process is divided into two stages: top forming and thin wall forming. The wall thickness forming at different stages is achieved by adjusting the processing parameters and controlling the side gap. The final formed structure obtained by the electrolytic machining process is consistent with the proposed honeycomb hole wall structure. The array honeycomb structure processed by the present invention is a deep blind hole. After processing, the honeycomb structure is integrated with the bottom plate, and the formed structure is an integral honeycomb wall plate. Compared with the manufacturing method of the traditional honeycomb sandwich panel welding thinner surface plates on the upper and lower surfaces of the honeycomb through-hole sandwich layer, the structural strength is higher and the reliability is better. The heat deformation ratio of the integral wall plate is consistent during the production and application process, and the integral structure is processed and formed at one time, which greatly saves the manufacturing time and cost of the honeycomb wall plate.

[0038] The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should be regarded as the protection scope of the present invention.

Claims

1. A lightweight integral honeycomb structure, comprising a base plate (11) and honeycomb array holes (12) arranged on the base plate (11), characterized in that: The honeycomb array holes (12) are integrally formed with the bottom plate (11), and are smoothly transitioned to form array blind holes with a first rounded corner (13); the thickness of the top end (12a) of the honeycomb array hole (12) is greater than the thickness of the honeycomb hole wall body (12b); the top end (12a) of the hole wall and the honeycomb hole wall body (12b) are smoothly transitioned with a second rounded corner (14); The invention comprises a fixture seat (4), a sealed cavity (3), a cathode chuck (2), a spindle chuck (1) and a tool cathode (5); the sealed cavity (3) is fixed on the fixture seat (4); the workpiece (10) is mounted on the fixture seat (4) for positioning and is placed at the bottom of the sealed cavity (3) at the same time, and the cathode chuck (2) is fixedly connected to the spindle chuck (1); the spindle chuck (1) is provided with a liquid passage cavity (1a), and the cathode chuck (2) is provided with an array of through holes (2a), each of which is provided with a tool cathode (5); the spindle chuck (1) can drive the tool cathode (5) to be inserted into the sealed cavity (3) from above and move up and down, and the tool The cathode (5) is provided with an axial liquid passage (5a), the front end of the tool cathode (5) is provided with a machining blade (7), the middle or upper part of the sealed cavity (3) is provided with a liquid outlet (3a), the sealed cavity (3) and the cathode chuck (2), and the sealed cavity (3) and the workpiece (10) are sealed by a sealing member, the electrolyte can be injected into the sealed cavity (3) through the liquid passage cavity (1a), the array through hole (2a) and the axial liquid passage (5a) in sequence to immerse the gap between the workpiece (10) and the tool cathode (5), and the excess electrolyte can be discharged from the liquid outlet (3a), the tool cathode (5) is connected to the negative pole of the power supply, and the workpiece (10) is connected to the positive pole of the power supply; The tool cathode (5) is a tubular structure, an inverted cone hole (6) is provided at the bottom of the axial liquid passage (5a), a liquid outlet group hole (8) is provided between the inverted cone hole (6) and the processing edge (7), and the electrolyte in the axial liquid passage (5a) is discharged from the liquid outlet group hole (8) to the sealed cavity (3); The liquid outlet hole group (8) is arranged in a combination of a central single hole, six middle holes and an outer circular array of twelve holes; the cross section of the processing blade (7) is a regular hexagonal surface, and the six middle holes of the liquid outlet hole group (8) are six angular holes that are consistent with the angular direction of the processing blade (7); the outer circular array holes are staggered with the six angular holes. The side wall of the tool cathode (5) is covered with an insulating sleeve (9); The method for using the electrolytic processing device of the lightweight integral honeycomb structure specifically comprises the following steps: Step 1: The workpiece (10) is positioned and mounted on the fixture seat (4) with the bottom plane thereof. During processing, the spindle chuck (1) drives the tool cathode (5) distributed corresponding to the preset honeycomb structure to be synchronously fed in the vertical direction; Step 2: Calibrate and level the fixture, connect the tool cathode (5) to the negative pole of the power supply, and connect the workpiece (10) to the positive pole of the power supply; Step 3: Adjust the spindle chuck (1) to move downward to enter the tool setting state. When the tool cathode (5) contacts the workpiece (10), the spindle chuck (1) is immediately raised a certain distance as the initial machining gap to complete the tool setting. Step 4: introducing electrolyte, the electrolyte flows into the liquid passage cavity (1a) of the spindle chuck (1), disperses into each tool cathode (5) through the array through holes (2a) in the cathode chuck (2), enters the processing area through the liquid outlet group holes (8) at the bottom of the tool cathode (5), and finally flows out from the liquid outlet hole (3a) of the sealed cavity (3); Step 5, in the hole wall top processing stage, the tool cathode (5) is fed downward in a vertical direction at a fast speed to a processing depth to process the workpiece (10). The processing depth is adapted to the thickness of the hole wall top (12a). Due to the fast feeding speed, the side processing gap is small, thereby obtaining a larger top wall thickness and forming the hole wall top (12a); Step 6: After the processing of the top of the hole wall is completed, the process jumps to the stable forming stage to process the honeycomb hole wall body (12b). In this stage, the feeding speed of the tool cathode (5) is slower than that of the hole wall top processing stage, so that the second fillet (14) is formed at the connection between the hole wall top (12a) and the honeycomb hole wall body (12b). At the same time, the feeding speed of the tool cathode (5) is relatively slow, so that the side processing gap is relatively large, thereby obtaining a thinner honeycomb hole wall body thickness and forming the honeycomb hole wall body (12b); after the tool cathode (5) continues to feed to the specified processing position, the processing is stopped. At this time, the bottom end of the tool cathode (5) has not penetrated the bottom of the workpiece (10), and the bottom that has not been penetrated is the bottom plate (11). Since the connection between the honeycomb hole wall body (12b) and the bottom plate (11) is itself at the processing end position, when the tool cathode (5) stops working, the first fillet (13) is automatically formed by the electrolytic processing characteristics, and the spindle chuck (1) moves upward to drive the tool cathode (5) to leave the workpiece (10), completing the processing of the workpiece.

2. A lightweight integral honeycomb structure according to claim 1, characterized in that: The thickness of the cell wall top (12a) is greater than the thickness of the honeycomb cell wall body (12b).

3. A lightweight integral honeycomb structure according to claim 2, characterized in that: The height of the cell wall top (12a) is much smaller than the height of the honeycomb cell wall body (12b).

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