An electroforming nickel forming die, its manufacturing method and application method

Abstract

This invention discloses an electroforming nickel forming mold, its manufacturing method, and its application method. The core mold is made of 316L stainless steel and its structure is manufactured according to the inner surface of the product to be formed. The root of the conductive rod of the mold hanging rod is provided with an external thread, which is connected to the upper end face of the core mold through the external thread of the conductive rod and secured with a hexagonal nut. Small pressure blocks and large pressure blocks are fixedly installed on both sides of the core mold, respectively. The inner end face of the small pressure blocks and the large pressure blocks are each provided with two parallel mounting holes for installing a figurative auxiliary cathode. The technical solution provided by this invention solves the problem of the current lack of relevant solutions for the structural design and manufacturing of forming molds used in electroforming nickel.

Description

Technical Field

[0001] This invention relates to, but is not limited to, the field of electroforming mold design and manufacturing technology, and particularly to an electroforming nickel forming mold and its manufacturing and application methods. Background Technology

[0002] Electroforming nickel technology can replicate the morphology of the core mold surface, with low processing cost and good product consistency. It is suitable for manufacturing complex-shaped parts and parts with special materials and performance requirements that cannot be processed by machining or sheet metal forming.

[0003] Electroforming nickel involves placing a specialized mold, identical in appearance to the part to be manufactured, into a nickel-casting solution. Electrolytic deposition yields a blank part with the exact shape and dimensions specified in the design drawings. After demolding, excess material is removed via electrolysis or mechanical cutting to obtain the final part. The corrosion resistance and conductivity of the specialized nickel-casting mold material, the design and installation of auxiliary electrodes, the design of local insulation structures, and the manufacturing of the core mold directly affect the quality of the electroformed nickel part. Currently, no implementation schemes related to the structural design and manufacturing of the forming molds used in nickel-casting have been found. Summary of the Invention

[0004] The purpose of this invention is to solve the above-mentioned technical problems. This invention provides an electroforming nickel forming mold and its manufacturing and application methods to address the current lack of structural design and manufacturing solutions for forming molds used in electroforming nickel.

[0005] The technical solution of the present invention: The present invention provides an electroforming nickel forming mold and its manufacturing method, including: a core mold 1, a mold hanging rod 2, a small pressure block 3, a large pressure block 4, a figurative auxiliary cathode 5, an internal hexagonal screw 6, and a hexagonal nut 7;

[0006] The core mold 1 is made of 316L stainless steel, and its external structure is designed and manufactured according to the internal shape of the product to be formed. The mold hanging rod 2 includes a conductive rod body and a hook set at the top of the conductive rod body. The root of the conductive rod body is set with an external thread. The mold hanging rod 2 is connected to the upper end face of the core mold 1 through the external thread of the conductive rod body and is fastened with a hexagonal nut 7 so that the core mold 1 can be hung on the copper bar of the electroforming tank through the mold hanging rod 2.

[0007] One side of the core mold 1 is fixedly installed with a small pressure block 3 using an internal hex screw 6, and the other side is fixedly installed with a large pressure block 4 using an internal hex screw 6; the inner end faces of the small pressure block 3 and the large pressure block 4 are respectively provided with two parallel mounting holes for installing the figurative auxiliary cathode 5.

[0008] Optionally, in the electroforming nickel molding die as described above,

[0009] The mold hanging rod 2 consists of two rods, which are made of pure copper T2Y material.

[0010] Optionally, in the electroforming nickel molding die as described above,

[0011] The conductive rod of the mold hanging rod 2 is a square column structure integrally formed by wire cutting. The hook at the top of the conductive rod includes two hooks with opposite opening directions and arranged vertically.

[0012] Optionally, in the electroforming nickel molding die as described above,

[0013] Both the small pressure block 3 and the large pressure block 4 are made of nylon and are used to isolate the current at both ends of the core mold 1 during the electroforming nickel process.

[0014] Optionally, in the electroforming nickel molding die as described above, the figurative auxiliary cathode 5 includes two aluminum wires, which are installed side by side around the bottom tip of the core mold 1 to disperse the current and avoid excessive current concentration; after installation, the distance between the figurative auxiliary cathode 5 and the ridge line of the core mold 1 is 15mm to 20mm.

[0015] Optionally, in the electroforming nickel molding die as described above,

[0016] The core mold 1 is configured as a punch structure, with its outer surface conforming to the inner surface of the product to be formed. The core mold 1 is configured as a closed hollow structure and has reinforcing ribs inside.

[0017] Optionally, in the electroforming nickel molding die as described above,

[0018] The core mold 1 of the sealed hollow structure is segmented by laser 3D printing technology, and then seamlessly connected by laser cladding welding technology. Finally, it is formed into an integrated sealed hollow structure of the core mold 1 by grinding and polishing.

[0019] This invention also provides a method for manufacturing an electroforming nickel molding die, wherein the manufacturing method is used to form an electroforming nickel molding die as described in any of the above claims, the manufacturing method comprising:

[0020] Step 1: Determine the structure and size of the core mold based on the inner surface of the product to be molded. Divide the core mold into at least two sections according to its structure and size. Print the sections using 3D printing. After printing, weld the sections together using laser cladding welding to form the core mold. The resulting core mold is a sealed hollow structure with internal reinforcing ribs.

[0021] Step 2: Install small and large nylon pressure blocks at both ends of the core mold, and install them on the left and right sides of the core mold 1 with two hexagon socket screws respectively; fix the two aluminum wires of the figurative auxiliary cathode in the mounting holes inside the small and large pressure blocks, and after installation, the aluminum wires are the same shape as the bottom of the core mold;

[0022] Step 3: The conductive rod body with a square column structure and the hook located at the top of the conductive rod body are processed by wire cutting integral forming. The root of the processed conductive rod body has external threads, which are threaded to the top of the core mold and fastened with a hexagonal nut. The hook at the top of the conductive rod body is set as a double hook structure with high and low hooks.

[0023] This invention also provides a method for applying an electroforming nickel forming die, wherein the method is the application of the electroforming nickel forming die as described in any of the above embodiments in the electroforming nickel process, including:

[0024] Step 1: Before performing electroforming nickel, insert the shaped auxiliary cathode into the mounting holes inside the large and small pressure blocks and connect it to the mold hanging rod with copper wire. Place the electroforming nickel forming mold into the electroforming nickel bath and hang it on the cathode copper rod using the high hook of the mold hanging rod. Hang the nickel-containing anode plate on the anode copper rod in the electroforming nickel bath with polyester cloth.

[0025] Step 2: After preheating for 3-5 minutes, power is turned on, and nickel ions in the electroforming nickel solution are reduced and deposited onto the mandrel to form a pure nickel part;

[0026] Step 3: After 5 hours of electroforming, lift the mold and quickly flip the core mold over without leaving the electroforming nickel solution. Use the low hook on the other side to hang the low hook on the copper bar and continue electroforming. After 12 hours of electroforming, lift the mold hanging rod and remove the mold from the solution.

[0027] The beneficial effects of the present invention: The embodiments of the present invention provide an electroforming nickel forming mold and its manufacturing and application methods, specifically a structure, manufacturing and application method of a long-life, high-quality, and lightweight electroforming nickel forming mold, which has the following beneficial effects:

[0028] 1. Based on the electroforming mechanism, design the forming mold used in the electroforming nickel process. Solve the problem of local isolation and protection of the core mold by setting a nylon pressure block, as well as the problem of installing the figurative auxiliary cathode.

[0029] 2. Through material selection and structural design, the form and structure of the mold hanging rod, the figurative auxiliary cathode, the isolation at both ends of the core mold, and the nylon pressure block for installing the figurative auxiliary cathode are clearly defined. Aluminum wire with good conductivity, soft texture, and easy shape adjustment is selected as the figurative auxiliary electrode to avoid the rough appearance and nodules of the electroformed product caused by the tip discharge of the core mold during the electroforming process. This improves the conductivity of the mold during the electroforming process, thereby improving the manufacturing quality of the electroformed product and indirectly shortening the electroforming time.

[0030] 3. The high and low dual-structure mold hook design can adapt to changes in the horizontal plane and solve the problem of the solution level dropping during long-term electroforming.

[0031] 4. Laser 3D printing technology is used to realize the segmented processing of the closed hollow structure of the core mold. After printing, the core mold is seamlessly connected by laser cladding welding technology. The core mold is integrated by grinding and polishing technology, which ensures the processing accuracy of the mold, reduces stress deformation, and realizes the lightweight design and manufacturing of the mold. The total weight is reduced by 1 / 2 compared with the electroformed nickel core mold formed by solid stainless steel sheet.

[0032] 5. Using 316L material to process the core mold can ensure the hardness and wear resistance of the core mold, as well as resist the corrosion of electroforming nickel solution and work at a temperature of 55℃-60℃ for a long time, thereby improving the service life of the mold and having a certain economic advantage.

[0033] 6. The electroforming nickel forming mold and its manufacturing and application methods provided in the embodiments of the present invention provide a high-quality and lightweight forming structure and manufacturing method for electroforming nickel forming molds for large parts, and can be extended to the production and manufacturing of other electroforming nickel forming molds. Attached Figure Description

[0034] The accompanying drawings are used to provide a further understanding of the technical solution of the present invention and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present invention and do not constitute a limitation on the technical solution of the present invention.

[0035] Figure 1 This is a schematic diagram of the structure of an electroforming nickel forming mold provided in an embodiment of the present invention;

[0036] Figure 2 for Figure 1 The schematic diagram shown in the embodiment illustrates a solid core mold in the electroforming nickel forming die.

[0037] Figure 3 for Figure 1 The schematic diagram shown in the embodiment illustrates a closed, hollow core mold in the electroforming nickel forming die.

[0038] Figure 4 for Figure 1 The schematic diagram of the mold hanging rod in the electroforming nickel forming mold provided in the embodiment shown;

[0039] Figure 5 for Figure 1 The schematic diagram of the small pressure block in the electroforming nickel forming mold provided in the embodiment shown is as follows;

[0040] Figure 6 for Figure 1 The illustrated embodiment provides a schematic diagram of the structure of the large pressure block in the electroforming nickel molding die.

[0041] Explanation of reference numerals in the attached figures:

[0042] 1: Core mold;

[0043] 2: Mold hanging rod;

[0044] 3: Small compressed blocks;

[0045] 4: Large compressed blocks;

[0046] 5: Pictographic auxiliary cathode;

[0047] 6: Socket head cap screws;

[0048] 7: Hexagonal nuts;

[0049] 8: Outline cutting lines;

[0050] 9: Apply clear varnish to the boundary. Detailed Implementation

[0051] To make the purpose, technical solutions and advantages of the present invention more clearly understood, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, unless there is a conflict, the embodiments and features in the embodiments of the present application can be combined with each other in any manner.

[0052] The advantages, applicability, and process methods of electroforming nickel technology have been explained in the background section above. Furthermore, the quality of electroformed nickel parts is directly affected by factors such as the material's resistance to electroforming solution corrosion, conductivity, the design and installation of auxiliary electrodes, the design of local insulation structures, and the manufacturing of the core mold. Therefore, the quality of the electroforming nickel mold is a crucial factor influencing the quality of electroformed nickel products.

[0053] Currently available patents include CN104674309B, which describes a method and apparatus for forming electroformed nickel parts, including the installation of a figurative auxiliary cathode support, the electroforming method, and electroforming process parameters; and "Research on Electroplating Process of Electroformed Rotor Sheets" in *Electroplating and Environmental Protection*, Vol. 2009 (No. 4). All of these studies focus on the electroformed nickel forming process for helicopter rotor tip fairings, but do not specifically address the mold structure design and manufacturing technology for electroformed nickel parts. Patent CN104674309B only specifies a method for manufacturing a figurative cathode core mold used in the electroforming of nickel parts.

[0054] In view of the lack of relevant solutions for the structural design and manufacturing of forming molds used in electroforming nickel in the existing technology, this invention proposes an electroforming nickel forming mold and its manufacturing method and application method.

[0055] The present invention provides the following specific embodiments, which can be combined with each other. For the same or similar concepts or processes, they may not be described again in some embodiments.

[0056] Before describing the electroforming nickel forming mold and its manufacturing method provided in the embodiments of the present invention, the existing electroforming nickel forming process will first be described. The current electroforming nickel forming process is as follows:

[0057] Mold inspection – organic solvent degreasing – isolation and protection – chemical manual degreasing – running hot water washing – running cold water washing – electroforming nickel – running cold water washing – running hot water washing – drying – demolding – cutting and shaping – inspection.

[0058] Main process description:

[0059] a. Mold inspection:

[0060] Before electroforming nickel, the surface of the forming mold should be inspected to ensure there are no defects such as dents or scratches. If any defects are found, the mold should be repaired and qualified before it can be used.

[0061] b. Degreasing with organic solvents:

[0062] Depending on the oil stains on the surface of the molding die, use organic solvents such as acetone and trichloroethylene to wipe and remove the oil stains on the mold surface in order to obtain a good electroforming nickel deposition layer.

[0063] c. Isolation:

[0064] The non-nickel deposited parts of the molding die are isolated and protected using chlorinated rubber or other insulating materials.

[0065] d. Chemical manual degreasing:

[0066] Clean the surface of the electroforming nickel molding die with detergent, scouring powder, or soap.

[0067] e. Electroforming of nickel:

[0068] Deposition was carried out in a nickel solution within an aminosulfonic acid system.

[0069] f. Drying: Use compressed air at a temperature below 60°C to dry the molding die and its deposited layer.

[0070] g. Demolding: Use special tools to peel the nickel part off the core mold of the molding die, and prevent scratching the mold during the demolding process.

[0071] h. Product processing and shaping: Use mechanical or electrochemical cutting methods to remove excess parts of the parts and trim them to meet the requirements of the design model or drawings.

[0072] Inspection: The surface of electroformed parts should be clean, smooth, and a milky white with a dark sheen. Slight blemishes and bumps are permissible. Part dimensions should be inspected according to the drawings. Parts should be handled while wearing rubber gloves and quality gloves during the electroforming process. Bumps on the part surface may be removed by grinding, but the part dimensions must be maintained.

[0073] Besides the electroforming process, other common surface treatment processes in nickel plating include organic solvent degreasing, isolation, chemical manual degreasing, running water washing, and drying. Before electroforming nickel, the mold surface is inspected for chips, scratches, and dents, and organic and inorganic oil contaminants are removed to ensure a uniform nickel part thickness during subsequent electroforming. The electroforming nickel process is a major influencing factor in propeller tip forming. The composition and main parameters of the low-stress electroforming nickel solution are as follows:

[0074]

[0075]

[0076] As can be seen from the parameters of the existing electroforming nickel process, during the electroforming of the propeller tip, the forming mold comes into contact with an acidic solution with a pH value <4. It is then suspended on the copper rod of the electroforming tank for an extended period under energized conditions, operating in a solution at approximately 55℃-60℃. Therefore, considering the usage and application of the forming mold in the electroforming nickel process, the following requirements are proposed for the forming mold: the mold material should possess certain resistance to acidic solution corrosion, resistance to medium-temperature solutions, sufficient mechanical strength, and good electrical conductivity, while its weight should be sufficient to meet the long-term load-bearing requirements of the copper rod in the electroforming tank.

[0077] The materials and core mold structures of commonly used electroforming nickel molding dies have revealed the following problems in long-term production applications:

[0078] 1. Core mold material issue

[0079] Electroforming nickel molding mandrels made of low-melting-point alloys can only be used once, resulting in high costs and poor consistency in appearance and dimensions of electroformed nickel products. Electroforming nickel molding mandrels made of 0Cr18Ni9 austenitic stainless steel through machining offer good resistance to corrosion from electroforming nickel solutions, but their insufficient hardness and poor wear resistance make them prone to chipping, scratches, and dents on the surface, reducing their service life and affecting the quality of electroformed nickel products.

[0080] For the reasons mentioned above, in the electroforming nickel molding die provided in the embodiments of the present invention, 316L material with good corrosion resistance, hardness and weldability and good economy is considered as the core mold material of the electroforming nickel molding die.

[0081] 2. The rod is broken or the conductivity is insufficient.

[0082] In the electroforming nickel process, the operator holds a hook at one end to lift the mold. Due to the thinness of the rod and the skewed angle of force application, the rod and the threaded part of the screw-connected rod break after long-term use, making it difficult to remove from the mold.

[0083] In addition, due to the excessive thinness of the rod, the conductivity during electroforming is insufficient. To increase the electrodeposition rate, adjusting the power supply parameters to increase the current causes overheating of the rod and mold; if the current is too low, impurities such as copper, lead, and zinc ions in the electroforming nickel solution are easily deposited on the mold surface along with the nickel, directly affecting the purity of the formed propeller tip cover material; insufficient conductivity leads to prolonged electroforming time for the propeller tip cover, delaying production and wasting energy.

[0084] Based on the above problems, in the electroforming nickel forming mold provided in the embodiments of the present invention, pure copper material T2Y is considered as the material of the rod in the electroforming nickel forming mold, and the diameter of the rod is ≥25mm.

[0085] 3. The length of the mold rod is fixed and cannot be adjusted.

[0086] In the electroforming nickel process, one end of the die is hooked onto a copper rod in the electroforming tank, while the other end is connected to the core mold via a rod. The core mold should be completely submerged below the solution level. During the long electroforming process, the solution temperature remains around 60°C, causing the solution concentration level to drop. Currently, the rod length in the die is fixed. After solution concentration, water needs to be added to ensure it remains submerged below the solution level. Adding water at too low a temperature can cause localized rapid cooling of the die, resulting in uneven temperature distribution and delamination of the nickel layer, leading to scrap. Adding water can also cause uneven solution concentration, affecting the deposition efficiency and quality of the nickel layer.

[0087] Based on the above problems, the electroforming nickel forming mold provided in this embodiment of the invention has a hook structure designed as a dual structure of high and low. When the horizontal level is found to be lowered during the electroforming nickel process, the tooling can be directly flipped in the solution. The hook conversion is achieved without the core mold leaving the electroforming solution. The low hook is used to ensure that the mold is still submerged below the horizontal level of the electroforming solution.

[0088] 4. Grinding mold weight

[0089] Using thick stainless steel plates and machining mandrels, taking a medium-sized helicopter rotor tip cover forming mold as an example, its weight exceeds 10kg. During the electroforming process, manual handling and crane loading and unloading operations, involving isolation and manual degreasing, easily cause damage to the mold surface if handled carelessly. In the electroforming process, cathode movement is used to improve nickel deposition quality, and the mold moves laterally with the cathode copper rod. Excessive mold weight reduces the service life of the mold rod, and the load-bearing capacity of the electroforming nickel cathode copper rod is limited, posing a significant safety hazard. In the electroforming nickel production of large parts, mold weight is a key issue restricting production and affecting product quality.

[0090] Based on the above problems, the electroforming nickel forming mold provided in this embodiment of the invention proposes a closed hollow structure design for the core mold, and then processes it by laser 3D printing technology in segments and laser cladding welding technology, thereby providing a lightweight and high-precision manufacturing method for electroforming nickel molds.

[0091] 5. Discharge at the tip of the molding die edge

[0092] Currently, due to tip discharge, the ends and bottom edges of electroforming nickel molding dies tend to accumulate a significant amount of nickel slag and nodules. The bottom of the molding die uses a conformal auxiliary electrode made of nickel wire, which results in substantial nickel slag and nodules on the surface of the product after electroforming. Furthermore, the nickel wire cannot be reused and must be discarded, increasing the production cost of electroforming nickel. Nickel wire has a hardness of HRC28, higher than copper, stainless steel, and aluminum wires commonly used in plating processes, making it less prone to bending when fabricating conformal auxiliary electrodes.

[0093] To address the aforementioned issues, the electroforming nickel molding die provided in this embodiment of the invention employs two soft and easily moldable aluminum wires to create a figurative auxiliary electrode, which is then installed side-by-side near the tip of the bottom of the core mold. This disperses the current, prevents excessive current concentration, reduces the thickness of the bottom of the electroformed part, and thus yields an electroformed nickel product with uniform thickness. Furthermore, nylon pads are added to both ends of the core mold to isolate the current at both ends of the mold and facilitate the fixing and installation of the figurative auxiliary cathode.

[0094] In summary, based on the analysis of the factors contributing to the various problems exposed in the long-term production application of existing electroforming nickel molding dies regarding materials and core mold structures, the researchers of this invention have proposed corresponding solutions to specific problems, forming the design concept of the electroforming nickel molding die provided in the embodiments of this invention, thereby obtaining the specific structure of the electroforming nickel molding die and the material selection of each component.

[0095] In a first aspect, embodiments of the present invention provide an electroforming nickel molding die:

[0096] Figure 1 This is a schematic diagram of the structure of an electroforming nickel molding die provided in an embodiment of the present invention. The design concept of the electroforming nickel molding die provided in this embodiment of the present invention has been explained above. Based on the above analysis of the design concept, the main structure of the electroforming nickel molding die provided in this embodiment of the present invention includes: a core mold 1, a die hanging rod 2, a small pressure block 3, a large pressure block 4, a figurative auxiliary cathode 5, an internal hexagonal screw 6, and a hexagonal nut 7.

[0097] In this embodiment of the invention, the core mold 1 is made of 316L stainless steel. The outer shape of the core mold 1 is designed and manufactured according to the inner surface of the product to be formed. The mold hanging rod 2 includes a conductive rod body and a hook set at the top of the conductive rod body. The root of the conductive rod body is set with an external thread. The mold hanging rod 2 is connected to the upper end face of the core mold 1 by the external thread of the conductive rod body and is fastened with a hexagonal nut 7 to prevent loosening and falling off, so that the core mold 1 can be hung on the copper rod of the electroforming tank by the mold hanging rod 2.

[0098] In this embodiment of the invention, a small pressure block 3 is fixedly installed on one side of the core mold 1 using an internal hex screw 6, and a large pressure block 4 is fixedly installed on the other side using an internal hex screw 6; the inner end faces of the small pressure block 3 and the large pressure block 4 are respectively provided with two parallel mounting holes for installing the figurative auxiliary cathode 5.

[0099] In this embodiment, the mold hanging rod 2 has two components, and to ensure conductivity, it is made of pure copper T2Y material. Figure 4 As shown, Figure 1 The schematic diagram of the hook structure in the electroforming nickel molding die provided in the embodiment shown.

[0100] In this embodiment, there is one small pressure block 3 and one large pressure block 4, both made of nylon. Two parallel Φ5.1 mounting holes are drilled at both ends of the small pressure block 3 and the large pressure block 4 for mounting the figurative auxiliary cathode 5. The figurative auxiliary cathode 5 consists of two Φ5 aluminum wires, which are used to isolate the current at both ends of the core mold 1 in the electroforming nickel process to avoid excessive current concentration. After installation, the distance between the figurative auxiliary cathode 5 and the ridge line of the core mold 1 is 15mm to 20mm. Figure 5 for Figure 1 The schematic diagram of the small pressure block in the electroforming nickel forming mold provided in the embodiment shown is as follows; Figure 6 for Figure 1 The illustrated embodiment provides a schematic diagram of the structure of the large pressure block in the electroforming nickel molding die.

[0101] In this embodiment, the conductive rod of the mold hanging rod 2 is a square column structure integrally formed by wire cutting. The cross-section of the square column is, for example, 25mm×25mm. The hook at the top of the conductive rod includes two hooks with opposite opening directions and arranged vertically, forming a double hook structure with high and low hooks. The mold hanging rod 2 is connected and fixed to the core mold 1 by screw connection, and the mold hanging rod 2 can be replaced in time as needed.

[0102] It should be noted that the electroforming nickel forming process is a process of forming from the inside out. Therefore, in the design of the core mold 1, the core mold 1 is set as a punch structure, and its outer surface fits the inner surface of the product to be formed. Figure 2 for Figure 1 The schematic diagram shown in the embodiment illustrates a solid core mold in the electroforming nickel forming die. Figure 3 for Figure 1 The illustrated embodiment provides a schematic diagram of a closed, hollow core mold in an electroforming nickel molding die. Based on the actual size of the product, the core mold 1 is designed as a closed, hollow structure to reduce the mold's weight. To ensure that the core mold 1 itself meets the requirements of actual use, internal reinforcing ribs are designed.

[0103] If traditional machining methods are insufficient to fabricate the sealed hollow core mold designed in this invention, then to ensure corrosion resistance, strength, temperature resistance, and electrical conductivity, 316L material is selected to prepare the core mold 1 in this embodiment. Compared to products manufactured by machining thick plates, it has been verified that the weight of the core mold 1 can be reduced by 30-50% while maintaining the same robustness. Therefore, laser 3D printing technology is used to manufacture the core mold 1 in this embodiment.

[0104] In practical applications, in order to ensure the processing accuracy of the core mold 1, reduce stress deformation during processing, and ensure the overall structural strength of the core mold 1, a segmented printing method is used to print the closed cavity. After printing, laser cladding welding technology is used for seamless connection. Then, the core mold 1 is formed into an integrated sealed hollow structure through grinding and polishing.

[0105] To ensure accurate cutting of the propeller tip sheath after molding, the core mold 1 is usually designed with outline cutting lines. These lines are typically 0.2mm deep and 0.5mm wide. After the propeller tip sheath is molded, these outline lines are formed to facilitate subsequent cutting. Figure 2 The outer shape cutting line 8.

[0106] In addition, the forming allowance for the propeller tip is generally 20mm. The portion beyond the 20mm cut line is not electroformed. This un-electroplated portion is isolated with chlorinated vinyl varnish. Therefore, the surface of the core mold 1 should also be marked with a varnish coating boundary. The varnish coating boundary is generally 0.2mm deep and 0.5mm wide. The portion beyond the varnish coating boundary is the isolation area. Figure 2 The boundary of the varnish in the middle is 9.

[0107] The electroforming nickel forming mold provided in the above embodiments of the present invention has the following characteristics:

[0108] 1. Based on the electroforming mechanism, a molding die for the electroforming process is designed. A nylon pressure block is used to address the issues of local isolation and protection of the core mold and the installation of the figurative auxiliary cathode. Because the bottom of the core mold exhibits tip discharge, the bottom edge becomes rough after electroforming. Adding a figurative auxiliary cathode ensures uniformity and fineness of the electroformed layer thickness. Specifically, aluminum wire is used as the figurative auxiliary cathode. Due to its good flexibility, aluminum wire can conform to the shape of the core mold bottom, ensuring conductivity.

[0109] 2. Through material selection and structural design, the materials and structural forms of the mold hanging rod and the figurative auxiliary cathode are clearly defined to improve the conductivity of the forming mold during the electroforming process, thereby improving the manufacturing quality of electroformed products. A 25mm×25mm (cross-section) square column, integrally machined by wire cutting, is used as the mold hanging rod, as follows: Figure 1 and Figure 4 The mold hanging rod and the core mold are connected and fixed by a screw connection, allowing the mold hanging rod to be replaced as needed. Figure 1 and Figure 4 The conductive rod has hooks on both sides. After the solution is concentrated and evaporated, the hook on the other side is used after the electroplating tank level drops.

[0110] 3. The hook at one end of the conductive rod is designed as a double hook with varying heights, allowing for adjustment of the mold height to accommodate changes in the horizontal plane during electroforming. For example... Figure 1 and Figure 4 As shown.

[0111] 4. Laser 3D printing technology is used to achieve segmented processing of the closed hollow structure of the core mold. After printing, seamless connections are made using laser cladding welding technology. Then, grinding and polishing techniques are used to achieve a unified core mold, ensuring the mold's processing accuracy, reducing stress deformation, and lightening the mold's weight. For example... Figure 3 The core mold shown is a closed hollow structure.

[0112] 5. Using 316L material to process the core mold ensures the hardness and wear resistance of the core mold, as well as resistance to corrosion from electroforming nickel solution and long-term immersion in medium-temperature solution, which is economical.

[0113] Secondly, embodiments of the present invention provide a method for manufacturing an electroforming nickel molding die:

[0114] Based on the structural and material characteristics of the electroforming nickel forming mold provided in the above embodiments of the present invention, the present invention provides a method for manufacturing the electroforming nickel forming mold, the specific implementation of which includes the following:

[0115] The molding die structure used for electroforming a large rotor tip cladding for a certain type of helicopter consists of a core mold 1, a die hanger 2, a small pressure block 3, a large pressure block 4, a figurative auxiliary cathode 5, an internal hexagonal screw 6, and a hexagonal nut 7. The manufacturing method is as follows:

[0116] (1) The core mold 1 has a closed hollow structure. To ensure a certain strength, a cross-shaped support structure is added inside the core mold 1. The material is 316L stainless steel. According to the size of the core mold 1, the core mold 1 is divided into two sections and printed in sections using 3D printing. After printing, the two sections are welded together by laser cladding welding. The weld seam is then ground and polished to ensure processing accuracy and smoothness, and to reduce stress deformation.

[0117] (2) Small nylon pressure blocks 3 and large nylon pressure blocks 4 are fixedly installed at both ends of the core mold 1. They are installed on the left and right sides of the core mold 1 using two hexagonal screws 6 respectively. The nylon pressure blocks can block the current and are used for local isolation and protection of the non-electroforming parts at both ends of the core mold 1. The nylon pressure blocks at both ends are equipped with holes of Φ5.1 and fixing bolts for fixing and installing the two ends of the aluminum wire of the figurative auxiliary cathode 5 at the bottom of the core mold 1. The figurative auxiliary cathode 5 is a Φ5 aluminum wire. It is adjusted to be the same shape as the bottom of the core mold 1 by taking advantage of the flexibility of the aluminum wire. After installation, it is about 15mm to 20mm away from the ridge line of the core mold 1.

[0118] (3) The mold hanging rod used for mounting and conducting the core mold 1 is a 25mm×25mm square prism integrally formed by wire cutting. The material is pure copper T2Y. It is connected and fixed to the core mold 1 by a hexagonal nut 7. The threaded structure at the root is threaded to the core mold 1 and tightened with the hexagonal nut 7 to prevent loosening and falling off. The mold hanging rod can be replaced at any time according to storage, maintenance and other needs. The conductive rod and hook in the mold hanging rod are integrated and collectively referred to as mold hanging rod 2. The hook at the other end of the conductive rod is designed as a double hook with high and low positions, which can adjust the height of the mold as needed to adapt to changes in the horizontal plane during the electroforming process.

[0119] Thirdly, embodiments of the present invention provide an application method for an electroforming nickel molding die:

[0120] Based on the structural and material characteristics of the electroforming nickel forming mold provided in the above embodiments of the present invention, the present invention provides an application method of the electroforming nickel forming mold, the specific implementation of which includes the following:

[0121] a. Mold Inspection

[0122] Before electroforming, the mold hanging rod 2, small pressure block 3, large pressure block 4, and figurative auxiliary cathode 5 are assembled onto the core mold 1 using fasteners such as internal hexagonal screws 6 and hexagonal nuts 7. The mold is then inspected for defects such as dents and scratches. It is only used after the inspection meets the requirements.

[0123] b. Degreasing with organic solvents

[0124] Depending on the oil stains on the surface of the molding die, acetone is used to remove the oil.

[0125] c. Isolation

[0126] The surfaces of the molding die that are not to be nickel-formed are isolated with chlorinated vinyl varnish according to the process lines on the core mold.

[0127] d. Chemical manual degreasing

[0128] Clean the electroformed nickel surface with detergent, laundry detergent, or soap foam.

[0129] e. Wash with running hot water

[0130] Temperature 50℃-70℃, washing time greater than or equal to 2 minutes.

[0131] f. Wash with running cold water

[0132] At room temperature, wash for 2 minutes or more.

[0133] g. Electroforming nickel molding

[0134] Insert the shaped auxiliary cathode 5 into the mounting holes on the inner side of the large pressure block 4 and the small pressure block 3, and connect it to the mold hanging rod 2 with copper wire. Place the electroforming nickel forming mold tooling into the electroforming nickel bath and hang it on the cathode copper rod using the mold hanging rod 2. Hang the nickel-containing anode plate on the anode copper rod in the electroforming nickel bath with a polyester cloth cover. After preheating for 3-5 minutes, turn on the power. The nickel ions in the solution are reduced and deposited onto the core mold to form a pure nickel part.

[0135] After approximately 5 hours of electroforming, lift the mold and quickly flip it over without removing the core mold from the solution. Use the low hook on the other side to hook the low hook onto the copper rod and continue electroforming. After 12 hours of electroforming, lift the rod or hook to remove the mold from the solution. If the mold is relatively light, it can be removed manually and proceed to the next cleaning process.

[0136] h. Wash with running cold water

[0137] At room temperature, wash for 2 minutes or more.

[0138] i. Wash with running hot water

[0139] Temperature 50℃-70℃, washing time greater than or equal to 2 minutes.

[0140] g. Drying

[0141] Dry with clean, water-free, and oil-free compressed air.

[0142] k. Demolding

[0143] Use special tools to peel the parts off the core mold, and prevent scratching the mold during the demolding process.

[0144] l. Product cutting and shaping

[0145] The excess parts of the product are trimmed off along the cutting lines of the shaped product, and the product is then shaped to conform to the drawings.

[0146] It should be noted that the preparation method of the electroforming nickel bath solution in this embodiment of the invention is as follows:

[0147] (1) Add one-third of the deionized water to the tank and inject the nickel aminosulfonate solution into the tank;

[0148] (2) Dissolve nickel chloride in deionized water and then pour it into the tank;

[0149] (3) Dissolve boric acid in heated deionized water (temperature < 70°C) and then pour it into the tank;

[0150] (4) Dissolve Triton X100 in hot deionized water and then pour it into the tank;

[0151] (5) Add deionized water to the specified level.

[0152] (6) The pH value should be maintained between 3.5 and 4.0. If the pH value is too high, use ammonia sulfonic acid to adjust it; if the pH value is too low, use hydrogen peroxide to adjust it.

[0153] The electroforming nickel forming mold, its manufacturing method, and its application method provided in this invention specifically represent the structure, manufacturing, and application method of a long-life, high-quality, and lightweight electroforming nickel forming mold, which has the following beneficial effects:

[0154] 1. Based on the electroforming mechanism, design the forming mold used in the electroforming nickel process. Solve the problem of local isolation and protection of the core mold by setting a nylon pressure block, as well as the problem of installing the figurative auxiliary cathode.

[0155] 2. Through material selection and structural design, the form and structure of the mold hanging rod, the figurative auxiliary cathode, the isolation at both ends of the core mold, and the nylon pressure block for installing the figurative auxiliary cathode are clearly defined. Aluminum wire with good conductivity, soft texture, and easy shape adjustment is selected as the figurative auxiliary electrode to avoid the rough appearance and nodules of the electroformed product caused by the tip discharge of the core mold during the electroforming process. This improves the conductivity of the mold during the electroforming process, thereby improving the manufacturing quality of the electroformed product and indirectly shortening the electroforming time.

[0156] 3. The high and low dual-structure mold hook design can adapt to changes in the horizontal plane and solve the problem of the solution level dropping during long-term electroforming.

[0157] 4. Laser 3D printing technology is used to realize the segmented processing of the closed hollow structure of the core mold. After printing, the core mold is seamlessly connected by laser cladding welding technology. The core mold is integrated by grinding and polishing technology, which ensures the processing accuracy of the mold, reduces stress deformation, and realizes the lightweight design and manufacturing of the mold. The total weight is reduced by 1 / 2 compared with the electroformed nickel core mold formed by solid stainless steel sheet.

[0158] 5. Using 316L material to process the core mold can ensure the hardness and wear resistance of the core mold, as well as resist the corrosion of electroforming nickel solution and work at a temperature of 55℃-60℃ for a long time, thereby improving the service life of the mold and having a certain economic advantage.

[0159] 6. The electroforming nickel forming mold and its manufacturing and application methods provided in the embodiments of the present invention provide a high-quality and lightweight forming structure and manufacturing method for electroforming nickel forming molds for large parts, and can be extended to the production and manufacturing of other electroforming nickel forming molds.

[0160] While the embodiments disclosed in this invention are as described above, the content is merely for the purpose of facilitating understanding of the invention and is not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and changes to the form and details of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection of this invention shall still be determined by the scope defined in the appended claims.

Claims

1. An electroforming nickel forming mold, characterized in that, include: Core mold (1), mold hanging rod (2), small pressure block (3), large pressure block (4), figurative auxiliary cathode (5), internal hex screw (6) and hex nut (7); The core mold (1) is made of 316L stainless steel. The external structure of the core mold (1) is designed and manufactured according to the internal shape of the product to be formed. The mold hanging rod (2) includes a conductive rod body and a hook set at the top of the conductive rod body. The root of the conductive rod body is set with an external thread. The mold hanging rod (2) is connected to the upper end face of the core mold (1) through the external thread of the conductive rod body and is fastened with a hexagonal nut (7) so that the core mold (1) can be hung on the copper rod of the electroforming tank through the mold hanging rod (2). The hook at the top of the conductive rod body includes two hooks with opposite opening directions and arranged vertically. One side of the core mold (1) is fixedly installed with a small pressure block (3) using an internal hexagon screw (6), and the other side is fixedly installed with a large pressure block (4) using an internal hexagon screw (6). The inner end faces of the small pressure block (3) and the large pressure block (4) are respectively provided with two parallel mounting holes for installing a figurative auxiliary cathode (5). The small pressure block (3) and the large pressure block (4) are both made of nylon, which is used to isolate the current at both ends of the core mold (1) in the electroforming nickel process. The figurative auxiliary cathode (5) includes two aluminum wires, which are installed side by side around the bottom tip of the core mold (1), specifically between the inner sides of the small pressure block (3) and the large pressure block (4). The figurative auxiliary cathode (5) is connected to the mold hanging rod (2) through copper wire to disperse the current and avoid the current from being too concentrated. The electroforming nickel forming mold is used in the process of electroforming nickel. First, the high hook of the mold hanging rod (2) is used to hang on the cathode copper rod for electroforming. After electroforming for a period of time, the core mold is flipped over without leaving the electroforming nickel solution and the low hook on the other side is used to hang the low hook on the cathode copper rod to continue electroforming.

2. The electroforming nickel forming mold according to claim 1, characterized in that, The mold hanging rod (2) consists of two rods, and the material used is pure copper T2Y material.

3. The electroforming nickel forming mold according to claim 2, characterized in that, The conductive rod of the mold hanging rod (2) is a square column structure integrally formed by wire cutting.

4. The electroforming nickel forming die according to any one of claims 1 to 3, characterized in that, After installation, the distance between the pictographic auxiliary cathode (5) and the ridge line of the core mold (1) is 15mm~20mm.

5. The electroforming nickel forming die according to any one of claims 1 to 3, characterized in that, The core mold (1) is configured as a punch structure, and its outer surface fits the inner surface of the product to be formed. The core mold (1) is configured as a closed hollow structure and has reinforcing ribs inside.

6. The electroforming nickel forming mold according to claim 5, characterized in that, The core mold (1) of the sealed hollow structure is segmented by laser 3D printing technology, and then seamlessly connected by laser cladding welding technology. Finally, the core mold (1) is formed by grinding and polishing.

7. A method for manufacturing an electroforming nickel molding die, characterized in that, The manufacturing method described above is used to form an electroformed nickel molding die as described in any one of claims 1 to 6, the manufacturing method comprising: Step 1: Determine the structure and size of the core mold based on the inner surface of the product to be molded. Divide the core mold into at least two sections according to its structure and size. Print the sections using 3D printing. After printing, weld the sections together using laser cladding welding to form the core mold. The resulting core mold is a sealed hollow structure with internal reinforcing ribs. Step 2: Install small and large nylon pressure blocks at both ends of the core mold, and install them on the left and right sides of the core mold 1 with two hexagon socket screws respectively; fix the two aluminum wires of the figurative auxiliary cathode in the mounting holes inside the small and large pressure blocks, and after installation, the aluminum wires are the same shape as the bottom of the core mold; Step 3: The conductive rod body with a square column structure and the hook located at the top of the conductive rod body are processed by wire cutting integral forming. The root of the processed conductive rod body has external threads, which are threaded to the top of the core mold and fastened with a hexagonal nut. The hook at the top of the conductive rod body is set as a double hook structure with high and low hooks.

8. A method for applying an electroforming nickel molding die, characterized in that, The application method is the application method of the electroforming nickel forming die as described in any one of claims 1 to 6 in the electroforming nickel process, including: Step 1: Before performing electroforming nickel, insert the shaped auxiliary cathode into the mounting holes inside the large and small pressure blocks and connect it to the mold hanging rod with copper wire. Place the electroforming nickel forming mold into the electroforming nickel bath and hang it on the cathode copper rod using the high hook of the mold hanging rod. Hang the nickel-containing anode plate on the anode copper rod in the electroforming nickel bath with polyester cloth. Step 2: After preheating for 3-5 minutes, power is turned on, and nickel ions in the electroforming nickel solution are reduced and deposited onto the mandrel to form a pure nickel part; Step 3: After 5 hours of electroforming, lift the mold and quickly flip the core mold over without leaving the electroforming nickel solution. Use the low hook on the other side to hang the low hook on the copper bar and continue electroforming. After 12 hours of electroforming, lift the mold hanging rod and remove the mold from the solution.

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