3D printing forming method for complex structural part with inner runner
Through 3D printing forming methods, including model pre-treatment, powder drying, second LM forming, powder cleaning procedures and post-processing, the problem of difficult formation of complex in-belt runner structure parts is solved, and efficient forming and mechanical performance improvement is achieved .
Patent Information
- Application Number
- CN202411448325.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-17
- Publication Date
- 2025-01-17
AI Technical Summary
Due to its high melting point, low thermal conductivity and severe work hardening characteristics, it is difficult to form integrated through traditional mechanical processing methods. It requires split mechanical processing and welding. The second LM forming technology has high mechanical performance requirements. There are challenges in forming defects under service conditions.
3D printing and forming methods are adopted, including model pretreatment, powder drying, second LM forming, part substrate disassembly, powder cleaning procedures and post-processing. The specific steps include vibration powder cleaning, compressed air powder cleaning, ultrasonic cleaning, X-ray detection, Annealing heat treatment, solid solution and aging heat treatment ensure that the internal powder inside the part is completely cleared and mechanical properties are improved.
Effectively control the forming defects, realize the efficient forming of complex in-belt runner structural parts, breaking through the limitations of traditional processing methods, and is suitable for difficult-to-process material GH4169, improving the mechanical properties and forming quality of parts.
Smart Images
Figure CN119319260A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the technical field of 3D printing and forming, and in particular to a 3D printing and forming method for a complex structural part with an internal flow channel. Background Art
[0002] Second LM forming is a technology that rapidly melts metal powder under the action of high-energy laser beam and rapidly cools and solidifies. This technology breaks through the conventional ideas of deformation forming and removal forming in traditional manufacturing processes. It can directly obtain solid parts of any complex shape based on the three-dimensional digital model of the parts using metal powder without any fixtures and molds, realizing the new concept of "net forming" material processing, which is particularly suitable for parts with complex inner cavity structures or special-shaped thin walls that are difficult to process titanium alloys, high-temperature alloys, etc. A complex structural part with an internal flow channel, made of GH4169, has the characteristics of high melting point, low thermal conductivity, and severe work hardening. It is considered to be one of the most difficult metal materials to process. At the same time, due to the complex flow channel structure inside the part, the traditional mechanical processing method cannot be formed in one piece, and split mechanical processing plus welding is required.
[0003] Therefore, a 3D printing method for complex structural parts with internal flow channels is urgently needed. At the same time, due to the harsh service conditions of the parts and high requirements for the mechanical properties of the parts, it also poses a great challenge to the LM forming in seconds. Through process design, the forming of this complex structural part is completed. Summary of the invention
[0004] The present disclosure aims to solve at least one of the technical problems existing in the prior art or related art.
[0005] To this end, the present disclosure provides a 3D printing method for a complex structural part with an internal flow channel, comprising:
[0006] Model pre-processing, generating molding program according to preset model type;
[0007] Powder drying: Powder drying is carried out in vacuum equipment;
[0008] Seconds LM forming, using single layer scanning to sinter the first layer of powder, and then sintering layer by layer;
[0009] Parts substrate disassembly, disassembly of substrate with parts;
[0010] A powder cleaning procedure, including a powder cleaning process and a detection process, wherein the powder cleaning process is provided with multiple powder cleaning steps;
[0011] Parts post-processing includes annealing heat treatment, solution treatment and aging heat treatment.
[0012] In a feasible implementation, the powder cleaning process includes vibration powder cleaning, compressed air powder cleaning, ultrasonic cleaning powder cleaning, and X-ray detection to ensure that the powder in the part flow channel is completely cleared.
[0013] In a feasible implementation, the vibration powder cleaning is set to be performed twice, and the time of the two vibration powder cleanings is greater than 30 minutes; the compressed air powder cleaning is performed to inflate and blow the inside of the part from each powder cleaning hole, and the blowing time is 5 to 20 minutes.
[0014] In a feasible implementation manner, the powder material is dried in a vacuum drying oven, and the drying temperature is set at 75 to 85° C. for 5 to 6 hours.
[0015] In a feasible implementation, in the second LM molding step, when the oxygen content in the molding chamber is reduced to below 1000 PPM, the first layer of powder is sintered by single-layer scanning, and then sintered layer by layer.
[0016] In a feasible embodiment, in the second LM forming step, the powder layer thickness is 0.04 mm, the scanning interval is 0.06 to 0.10 mm, the solid speed is 900 to 1000 mm / s, the inner contour speed is 850 to 1000 mm / s, and the outer contour speed is 200 to 500 mm / s.
[0017] In a feasible implementation manner, in the annealing heat treatment process, the temperature is raised to 500±10°C with the furnace, kept warm for 0.5 hour, continued to be raised to 800±20°C, kept warm for 0.5 hour, raised to 950±20°C, kept warm for 1 hour, and high-purity nitrogen is passed to the range of 1×105Pa to 2×105Pa, and the furnace is taken out after the temperature reaches below 80°C.
[0018] In a feasible implementation manner, in the process of solution heat treatment, the parts are put into the furnace at a temperature not exceeding 100°C, and are heated to 500±20°C as the furnace heats up, and are kept warm for 0.5h; they are further heated to 800±20°C and kept warm for 0.5h; the temperature is raised to 1020±20°C, and after reaching the temperature, they are kept warm for 1h; during the above heating and insulation process, the heating rate does not exceed 300°C / h, the vacuum working pressure is maintained at 0.1 to 10Pa, and oil cooling is performed.
[0019] In a feasible implementation, in the aging heat treatment step, the temperature is raised to 720±20°C with the furnace, kept at this temperature for 8 hours, then cooled to 620±20°C within 2 hours, kept at this temperature for 8 hours, and oil-cooled.
[0020] In a feasible implementation, liquid sand blasting treatment is performed after the aging heat treatment, and the parameters of the liquid sand blasting are set to particle size 20 to 180 meshes, compressed air pressure 0.4 to 0.6 MPa, nozzle diameter 12.5 mm, and sand blasting distance ≥ 100 mm.
[0021] The above description is only an overview of the technical solution provided by the present disclosure. In order to more clearly understand the technical means of the present disclosure, it can be implemented according to the contents of the specification. In order to make the above and other features and effects of the present disclosure more obvious and easy to understand, the implementation methods of the present disclosure are specifically listed below. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.
[0024] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the exemplary embodiments below. The accompanying drawings are only for the purpose of illustrating exemplary embodiments and are not to be considered as limiting the present application. Also, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:
[0025] Figure 1 A schematic diagram of the structure added for the remainder of the present disclosure;
[0026] Figure 2 It is a schematic diagram of the structure of the entity support disclosed in the present invention.
[0027] in, Figure 1 to Figure 2 The corresponding relationship between the figure numbers and the component names is: 1-first margin; 2-second margin; 3-third margin; 4-solid support. DETAILED DESCRIPTION
[0028] In order to more clearly understand the above-mentioned objectives, features and advantages of the present disclosure, the scheme of the present disclosure will be further described below. It should be noted that the embodiments of the present disclosure and the features in the embodiments can be combined with each other without conflict.
[0029] In the following description, many specific details are set forth to facilitate a full understanding of the present disclosure, but the present disclosure may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present disclosure, rather than all of the embodiments.
[0030] At present, second LM forming is a technology that rapidly melts metal powder under the action of high-energy laser beam and rapidly cools and solidifies. This technology breaks through the conventional ideas of deformation forming and removal forming in traditional manufacturing processes. It can directly obtain solid parts of any complex shape based on the three-dimensional digital model of the parts and use metal powder without any fixtures and molds, realizing the new concept of "net forming" material processing, which is particularly suitable for parts with complex inner cavity structures or special-shaped thin walls that are difficult to process titanium alloys, high-temperature alloys, etc. A complex structural part with an internal flow channel, made of GH4169, has the characteristics of high melting point, low thermal conductivity, and severe work hardening. It is considered to be one of the most difficult metal materials to process. At the same time, due to the complex flow channel structure inside the part, the traditional mechanical processing method cannot be formed in one piece, and split mechanical processing plus welding is required.
[0031] Based on this, the embodiment of the present disclosure provides a 3D printing forming method for complex structural parts with internal flow channels, including: model pre-processing, generating a forming program according to a preset model type; powder material drying, drying the powder material in a vacuum device; second LM forming, sintering the first layer of powder by single-layer scanning, and then sintering layer by layer; part substrate disassembly, disassembling the substrate with the part; powder cleaning program, including a powder cleaning process and a detection process, and the powder cleaning process is provided with multiple powder cleaning processes; part post-processing, annealing heat treatment and solid solution and aging heat treatment of the part. The method disclosed in the present disclosure clarifies the selection of second LM forming direction of complex structural parts with internal flow channels, effectively controls the generation of forming defects, and forms the part by using second LM technology, breaking through the forming technology of the structural part. The present disclosure is simple and practical, easy to implement, and suitable for second LM forming of complex structural parts with internal flow channels.
[0032] The following is a detailed description of the 3D printing method for the complex structure with internal flow channel through a specific embodiment:
[0033] Reference Figures 1 to 2 As shown, the component body involved in the present disclosure is a complex structure with an inner flow channel, and its minimum wall thickness is 1 mm, which is a thin-walled structure. Specifically, the present disclosure takes the overall envelope size of the part as 60 mm × 40 mm × 180 mm as an example, which is a small structure.
[0034] The 3D printing forming method of a complex structural part with an inner flow channel disclosed in the present invention comprises:
[0035] Model pre-processing, generating a forming program according to the preset model type, may include placement, structural design, addition of allowance, model repair, slicing and generation of forming program, etc. Specifically, the addition of allowance and solid support is performed on the 3D model processing software UG, the parts are exported in the TL format, and the parts are repaired and placed in the Magic software, and the parts are sliced to generate the forming program. It should be noted that the addition of allowance in the present disclosure is as follows Figure 1 As shown, the reason for adding allowances at the first and second allowances is that the dimensional accuracy requirements at these two places are high, and 3D printing cannot guarantee the formation, so allowances need to be left to ensure the final size of the part through subsequent mechanical processing. The reason for adding allowances at the third allowance is not only the high accuracy requirements, but also to prevent the problem of height shortage of parts caused by deformation of the substrate. Figure 2 As shown, there is a horizontal overhanging surface at this location, and a solid support is added there to form a self-supporting structure. Compared with the traditional grid support, it has better strength and is easier to remove.
[0036] Powder drying is performed in a vacuum device. In some embodiments, the powder drying is performed in a vacuum drying oven, and the drying temperature is set to 75°C to 85°C for 5 to 6 hours. The drying temperature of the present disclosure is specifically set to 80. The drying time is set to 6 hours. Among them, a drying temperature below 75°C will result in a poor drying effect, and a drying temperature above 85°C will cause the powder to be over-dried.
[0037] After the powder drying step, install the scraper and substrate, lower the forming platform to a certain height, and then move the scraper above the platform. The scraper used by the equipment can be a rubber scraper. Remove the scraper to check the degree of damage and replace it with a new one if necessary. Move the scraper above the platform, loosen the top screw, so that the brush knife is in a free fall state, then the platform rises 5 mm, and tighten the top screw from the inside to the outside. After confirming that the powder collection barrel has been installed and the valve has been opened, perform the powder spreading operation, adjust the powder feeding amount to the preset amount, and fine-tune the substrate position according to the powder spreading effect until the substrate outline can be seen through the powder layer.
[0038] After the substrate position is determined, use special IPA and lens paper to clean the laser incident protective mirror in a spiral manner from the inside to the outside. Close the forming chamber door, turn on the platform heating, and perform gas washing in the forming chamber. The above scrapers, substrates and other applied equipment are conventional application equipment in this field, and their usage methods and structural characteristics will not be repeated here.
[0039] Seconds LM forming, single-layer scanning is used to sinter the first layer of powder, and then sintering is carried out layer by layer. Specifically, when the oxygen content in the forming chamber is reduced to below 1000PPM, single-layer scanning is used to sinter the first layer of powder, and then sintering is carried out layer by layer. The purpose of reducing the oxygen content to below 1000PPM is to prevent oxidation during the forming process of the parts. The powder layer thickness is 0.04 mm, the scanning interval is 0.06-0.10 mm, the solid speed is 900-1000 mm / s, the inner contour speed is 850-1000 mm / s, and the outer contour speed is 200-500 mm / s. If the value is lower or higher than the above parameter range, it may cause the powder material to not be burned through and warp or the powder material to be over-burned.
[0040] Part substrate disassembly, disassembly of the substrate with parts. Specifically, after the forming is completed, turn off the substrate heating, and in an argon-protected atmosphere, wait for the substrate temperature to naturally cool to room temperature, then open the forming chamber, turn on the explosion-proof vacuum cleaner to clean the powder on the chamber wall, and after the cleaning is completed, separate the powder in the equipment into primary recovery powder and secondary recovery powder, lower the forming chamber to the lowest point, move the forming chamber to the powder cleaning and pickup area, take out the powder in the forming chamber, unscrew the screws on the substrate in diagonal order, remove the substrate with parts and place it on the mobile vehicle platform, and finally use a vacuum cleaner to further clean the equipment. It should be noted that the primary powder is the unused powder in the powder delivery chamber, and the secondary powder is the powder in the forming chamber, powder collection chamber, part cavity and surface attachment.
[0041] The powder cleaning procedure includes a powder cleaning process and a detection process. The powder cleaning process is provided with multiple powder cleaning processes, which utilize the flow channel openings of the parts themselves for powder cleaning. In some embodiments, the powder cleaning process includes vibration powder cleaning, compressed air powder cleaning, ultrasonic cleaning powder cleaning, and X-ray detection to ensure that the powder in the flow channel of the part is completely cleared out. Furthermore, the vibration powder cleaning is set to twice, and the time for the two vibration powder cleanings is greater than 30 minutes. Specifically, the substrate is inverted and the powder is cleaned by knocking and vibrating. The powder flows out through the flow channel opening at the front end of the part. The powder cleaning time is more than 30 minutes. The angle is changed and the knocking and vibration powder cleaning is continued. The powder cleaning time is more than 30 minutes. If the vibration powder cleaning time is less than thirty minutes, the flow channel powder in the part cannot be completely cleared out, and there will be residual powder. The powder cleaning time is more than 30 minutes, which can ensure that the flow channel powder in other parts except the dead corners of the part is completely cleared. The compressed air powder cleaning is used to inflate and blow the inside of the parts from each powder cleaning hole. The blowing time is 5 to 20 minutes. This process is the last powder cleaning process and the final guarantee process for powder cleaning. If the blowing time is less than five minutes, the powder cleaning will not be thorough.
[0042] Parts are post-processed, and the parts are subjected to annealing heat treatment, solid solution treatment, and aging heat treatment. The parts need to be sent for annealing heat treatment within 24 hours after the parts are formed. In some embodiments, during the annealing heat treatment process, the temperature is raised to 500±10℃ with the furnace, kept warm for 0.5 hours, and then raised to 800±20℃, kept warm for 0.5 hours, and then raised to 950±20℃, kept warm for 1 hour, and high-purity nitrogen is passed to the range of 1×105Pa to 2×105Pa, and the parts are taken out of the furnace after reaching below 80℃. Furthermore, in the process of solution heat treatment, the parts are put into the furnace at no more than 100°C, and the temperature is raised with the furnace, heated to 500±20°C, and kept warm for 0.5h; continue to heat to 800±20°C, and keep warm for 0.5h; heat to 1020±20°C, and keep warm for 1h after the temperature is reached; in the above heating and insulation process, the heating rate does not exceed 300°C / h, and the vacuum working pressure is maintained at 0.1 to 10Pa, and oil cooling is performed. After solution heat treatment, the powder cleaning holes are sealed by welding. Furthermore, in the step of aging heat treatment, the temperature is raised to 720±20°C with the furnace, kept warm for 8 hours, cooled to 620±20°C within 2 hours, kept warm for 8 hours, and oil cooled. In some embodiments, liquid sand blasting is performed after aging heat treatment, and the abrasive can be selected from corundum sand. The parameters of liquid sand blasting are set as follows: particle size 20 to 180 mesh, compressed air pressure 0.4 to 0.6 MPa, nozzle diameter 12.5 mm, and sand blasting distance ≥ 100 mm. The above parameter range is the necessary range to ensure the performance of the parts. If it is lower or higher than this range, the performance of the parts cannot be achieved.
[0043] In the present disclosure, the terms "first", "second", and "third" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance; the term "plurality" refers to two or more, unless otherwise expressly defined. The terms "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present disclosure can be understood according to the specific circumstances.
[0044] In the description of the present disclosure, it is necessary to understand that the directions or positional relationships indicated by the terms "up", "down", "left", "right", "front", "back", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present disclosure and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation, and therefore, should not be understood as a limitation on the present disclosure.
[0045] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.
[0046] The above are only preferred embodiments of the present disclosure and are not intended to limit the present disclosure. For those skilled in the art, the present disclosure may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present disclosure shall be included in the protection scope of the present disclosure.
Claims
1. A 3D printing method for complex structural parts with internal flow channels, characterized in that: include: Model pre-processing, generating molding program according to preset model type; Powder drying: Powder drying is carried out in vacuum equipment; Seconds LM forming, using single layer scanning to sinter the first layer of powder, and then sintering layer by layer; Parts substrate disassembly, disassembly of substrate with parts; A powder cleaning procedure, including a powder cleaning process and a detection process, wherein the powder cleaning process is provided with multiple powder cleaning steps; Parts post-processing includes annealing heat treatment, solution treatment and aging heat treatment.
2. The 3D printing forming method of a complex structural part with an inner flow channel according to claim 1, characterized in that: The powder cleaning process includes vibration powder cleaning, compressed air powder cleaning, ultrasonic cleaning powder cleaning, and X-ray detection to ensure that the powder in the part flow channel is completely cleaned out.
3. The 3D printing forming method of a complex structural part with an inner flow channel according to claim 1, characterized in that: The vibration powder cleaning is set to be performed twice, and the time of the two vibration powder cleanings is greater than 30 minutes; the compressed air powder cleaning is performed to inflate and blow the inside of the parts from each powder cleaning hole, and the blowing time is 5 to 20 minutes.
4. The 3D printing forming method of a complex structural part with an inner flow channel according to claim 1, characterized in that: The powder material is dried in a vacuum drying oven, with the drying temperature set at 75 to 85° C. and the drying time being 5 to 6 hours.
5. The 3D printing forming method of a complex structural part with an inner flow channel according to claim 1, characterized in that: In the second LM molding step, when the oxygen content in the molding chamber is reduced to below 1000 PPM, the first layer of powder is sintered by single-layer scanning, and then sintered layer by layer.
6. The 3D printing forming method of a complex structural part with an inner flow channel according to claim 1, characterized in that: In the second LM molding step, the powder layer thickness is 0.04 mm, the scanning interval is 0.06 to 0.10 mm, the solid speed is 900 to 1000 mm / s, the inner contour speed is 850 to 1000 mm / s, and the outer contour speed is 200 to 500 mm / s.
7. The 3D printing forming method of a complex structural part with an inner flow channel according to claim 1, characterized in that: In the annealing heat treatment process, the temperature is raised to 500±10°C with the furnace, kept warm for 0.5 hour, continued to be raised to 800±20°C, kept warm for 0.5 hour, raised to 950±20°C, kept warm for 1 hour, and high-purity nitrogen is passed to the range of 1×105Pa to 2×105Pa, and taken out of the furnace after reaching below 80°C.
8. The 3D printing forming method of a complex structural part with an inner flow channel according to claim 1, characterized in that: In the process of solution heat treatment, the parts are put into the furnace at a temperature not exceeding 100°C, and are heated to 500±20°C as the furnace heats up, and are kept warm for 0.5h; they are further heated to 800±20°C and kept warm for 0.5h; the temperature is raised to 1020±20°C, and after reaching the temperature, it is kept warm for 1h; during the above heating and insulation process, the heating rate does not exceed 300°C / h, the vacuum working pressure is maintained at 0.1 to 10Pa, and oil cooling is performed.
9. The 3D printing forming method of a complex structural part with an inner flow channel according to claim 1, characterized in that: In the aging heat treatment step, the temperature is raised to 720±20°C with the furnace, kept at this temperature for 8 hours, then cooled to 620±20°C within 2 hours, kept at this temperature for 8 hours, and oil-cooled.
10. The 3D printing forming method of a complex structural part with an inner flow channel according to claim 1, characterized in that: After the aging heat treatment, liquid sand blasting treatment is performed, and the parameters of the liquid sand blasting are set as follows: particle size 20 to 180 meshes, compressed air pressure 0.4 to 0.6 MPa, nozzle diameter 12.5 mm, and sand blasting distance ≥ 100 mm.