A device for improving powder utilization in a forming cylinder and an additive manufacturing method

Abstract

This invention belongs to the field of additive manufacturing technology, and provides a device for improving powder utilization in a forming cylinder and an additive manufacturing forming method. The device includes a forming cylinder, in which a substrate heating plate driven by a driving device is slidably mounted vertically. A printing substrate is fixedly mounted on the substrate heating plate. An inflation expansion device is located in the middle of the printing substrate, on the side of the printing substrate away from the substrate heating plate. In the working state, the inflation expansion device gradually increases in volume along the direction away from the printing substrate, and extends vertically as the printing substrate descends, forming a space-filling part within the forming cylinder. This invention uses an inflation expansion device to replace metal powder to fill most of the middle area of ​​the part, greatly reducing the amount of metal powder required for laser selective melting forming of the part, and significantly improving the actual utilization rate of metal powder.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing technology, and in particular to a device for improving powder utilization in a forming cylinder and an additive manufacturing forming method. Background Technology

[0002] Additive manufacturing, also known as 3D printing, is a technology that uses the gradual accumulation of materials to create solid parts. Parts manufactured using additive manufacturing possess excellent mechanical properties, are suitable for rapid prototyping of various materials, and have high material utilization. Selective laser melting (SLM) is a typical example of additive manufacturing, an advanced manufacturing technology based on the localized melting of metal powder using a laser beam. By directionally melting metal powder and depositing layers one by one, complex part structures can be created, achieving high-precision, high-quality, and high-flexibility 3D printing. With its high precision, high quality, and high flexibility, it is widely used in aerospace, automotive manufacturing, and medical device industries.

[0003] Laser selective melting (SLM) printing requires layering powder onto the printing substrate in the forming cylinder during the printing process, burying the entire part in the forming powder to complete the printing process. However, for ring-shaped parts or parts with low space utilization in the forming cylinder, a relatively large amount of forming powder is required to complete the printing. Moreover, most of the forming powder merely serves to fill the forming cylinder, resulting in low actual powder utilization, increased powder inventory, and increased fixed asset investment for enterprises in forming powder. Summary of the Invention

[0004] In order to overcome the deficiencies of the prior art as mentioned above, the inventors conducted in-depth research and, after a great deal of creative work, completed this invention.

[0005] Specifically, the technical problem to be solved by the present invention is to provide a device for improving the utilization rate of powder in a forming cylinder and an additive manufacturing forming method, so as to solve the technical problem that the actual utilization rate of powder in the current laser selective melting forming equipment and forming process is low, which increases the fixed asset investment in forming powder.

[0006] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0007] A device for improving powder utilization in a forming cylinder includes a forming cylinder. A substrate heating plate driven by a driving device is slidably installed in the forming cylinder along the vertical direction. A printing substrate is fixedly installed on the substrate heating plate. An inflation expansion device is provided at the middle position of the printing substrate and is located on the side of the printing substrate away from the substrate heating plate. When in operation, the inflation expansion device gradually increases in volume along the direction away from the printing substrate, and extends vertically as the printing substrate descends to form a space filling part located in the forming cylinder.

[0008] As an improved technical solution, a receiving groove is provided in the middle of the side of the printing substrate away from the heating plate of the substrate, and a laser printing forming area is formed on the top surface of the printing substrate surrounding the receiving groove. The inflation device is located in the receiving groove, and in the initial printing state, the inflation device is lower than the laser printing forming area or at the same height as the laser printing forming area.

[0009] As an improved technical solution, the storage slot is square or circular, the inflation device is adapted to the storage slot, and the bottom of the inflation device is fixedly connected to the printing substrate.

[0010] As an improved technical solution, the inflation device includes a deformable body and an inflation pump. The bottom of the deformable body is fixedly connected to the printed substrate. The air inlet of the inflation pump is connected to an air inlet pipe. The air inlet end of the air inlet pipe extends to the outside of the printed substrate. The air outlet of the inflation pump is connected to an air outlet pipe, and the inflation pump is connected to the deformable body through the air outlet pipe.

[0011] As an improved technical solution, the deformable part has a clearance groove on the side near the printing substrate, the air pump is located in the clearance groove, the printing substrate has an air pipe clearance hole corresponding to the air pump, and the air inlet pipe extends to the outside of the printing substrate through the air pipe clearance hole.

[0012] As an improved technical solution, the deformation form includes an inflatable airbag, the inflatable airbag being made of high-temperature resistant silicone material, and the high-temperature resistance range of the inflatable airbag being 200-300℃.

[0013] As an improved technical solution, the top of the inflatable airbag is provided with an airbag top plate, which is horizontally and fixedly installed on the top of the inflatable airbag.

[0014] As an improved technical solution, the deformable form includes telescopic housings that are sequentially and movably fitted together, with a sealing ring between adjacent telescopic housings, and the adjacent telescopic housings are slidably sealed by the sealing ring. When in the extended state, the outer diameter of the telescopic housing away from the printing substrate is larger than the outer diameter of the telescopic housing close to the printing substrate.

[0015] As an improved technical solution, the driving device includes a drive motor fixedly mounted on the forming cylinder, a lead screw is provided below the substrate heating plate, the top end of the lead screw is rotatably connected to the substrate heating plate, and a lead screw nut is provided on the forming cylinder and is driven by the drive motor, the lead screw nut being threadedly connected to the lead screw.

[0016] This invention also discloses a method for additive manufacturing based on the above-described powder utilization improvement device for forming cylinders, comprising the following steps:

[0017] S1. Use computer-aided design software to create a 3D model of the part to be printed;

[0018] S2. Convert the 3D modeling data in step S1 into slice data, and generate a laser scanning path through the slice conversion tool.

[0019] S3. The metal powder is evenly spread onto the printing substrate, and at the same time, the substrate heating plate is activated to heat the printing substrate.

[0020] S4. The laser beam scans according to a preset path, melting the metal powder into a liquid state at each scanning point to form a very small molten pool.

[0021] S5. The laser beam moves to the next scanning point and repeats the melting process of step S4 until one layer is printed.

[0022] S6. The molten metal powder adheres to the printing substrate to form a solid layer;

[0023] S7. The driving device drives the substrate heating plate and the printing substrate to descend by a set unit height. At the same time, the air pump works to inflate the deformable body, so that the volume of the deformable body increases by a unit height, ensuring that the height of the top of the deformable body in the forming cylinder remains unchanged.

[0024] S8. Spread a new layer of metal powder onto the printing substrate, and repeat the printing process of steps S4 and S5 to complete the printing of the next layer.

[0025] S9. The molten metal powder adheres to the previous solid layer, forming a new solid layer;

[0026] S10. Repeat steps S7, S8 and S9 until the printing of the entire part is completed.

[0027] S11. Depress the deformable part to restore it to its initial state, remove the printed part from the forming cylinder, discharge and clean the remaining metal powder in the forming cylinder, and drive the substrate heating plate and the printing substrate to reset.

[0028] After adopting the above technical solution, the beneficial effects of the present invention are:

[0029] This device for improving powder utilization in forming cylinders and its additive manufacturing method, when printing ring-shaped parts or parts with low space utilization in forming cylinders, achieves part printing in the laser printing forming area on the printing substrate. The inflation expansion device extends vertically along with the downward displacement of the printing substrate to form a space-filling part located in the forming cylinder, replacing metal powder to fill most of the middle area of ​​the part. The metal powder only needs to fill the cavity between the part and the inner wall of the forming cylinder and the small space between the inflation expansion device and the inner wall of the part, thereby greatly reducing the amount of metal powder required for laser selective melting forming of parts. The actual utilization rate of metal powder is greatly improved, effectively reducing the company's fixed asset investment in forming powder. In addition, during operation, the substrate heating plate continuously heats the printing substrate, thereby reducing the temperature difference between the printing substrate and the part, effectively avoiding the occurrence of part cracking, and ensuring the quality of part printing. Attached Figure Description

[0030] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0031] Figure 1 This is a schematic diagram of the structure of the powder utilization rate improvement device for the forming cylinder of the present invention;

[0032] Figure 2 This is a cross-sectional schematic diagram of the powder utilization rate improvement device for the forming cylinder of the present invention;

[0033] Figure 3 This is another cross-sectional view of the powder utilization rate improvement device for the forming cylinder of the present invention;

[0034] Figure 4 This is a schematic diagram of the mounting structure of the inflation device of the present invention on the printing substrate;

[0035] Figure 5This is a cross-sectional view of an embodiment of the present invention showing an inflation device mounted on a printing substrate.

[0036] Figure 6 This is a cross-sectional view of an inflation device mounted on a printing substrate according to another embodiment of the present invention.

[0037] Figure 7 This is a schematic diagram of the structure of an inflatable expansion device according to an embodiment of the present invention;

[0038] Figure 8 This is a cross-sectional view of an inflatable expansion device according to an embodiment of the present invention;

[0039] Figure 9 This is a cross-sectional view of the inflation device mounted on a printing substrate in another embodiment of the present invention.

[0040] Figure 10 for Figure 9 Enlarged structural diagram of part I in the middle;

[0041] Figure 11 This is a schematic diagram of the structure of the printing substrate of the present invention;

[0042] Figure label:

[0043] 1-Forming cylinder; 2-Substrate heating plate; 3-Printing substrate; 301-Mounting hole; 302-Receiving slot; 303-Air pipe clearance hole; 4-Inflatable airbag; 5-Inflatable pump; 6-Inlet pipe; 7-Outlet pipe; 8-Airbag top plate; 9-Telescopic shell; 10-Sealing ring; 11-Lead screw; 12-Sliding guide rod. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0045] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0046] Meanwhile, the meaning of "and / or" or "and / or" appearing throughout the text is that it includes three options. Taking "A and / or B" as an example, it includes option A, option B, or an option that satisfies both A and B.

[0047] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0048] like Figures 1 to 11 As shown in the figure, this embodiment provides a device for improving the powder utilization rate of a forming cylinder, including a forming cylinder 1. A substrate heating plate 2 driven by a driving device is slidably installed in the forming cylinder 1 along the vertical direction. A printing substrate 3 is fixedly installed on the substrate heating plate 2. An inflation expansion device is provided in the middle of the printing substrate 3, and the inflation expansion device is located on the side of the printing substrate 3 away from the substrate heating plate 2. When in working state, the inflation expansion device gradually increases in volume along the direction away from the printing substrate 3. The inflation expansion device extends vertically in the direction of the downward displacement of the printing substrate 3 to form a space filling part located in the forming cylinder 1. The space filling part replaces the metal powder to fill most of the middle area of ​​the part, thereby reducing the amount of metal powder used and improving the actual utilization rate of metal powder.

[0049] like Figure 3 As shown, in this embodiment, the printing substrate 3 has several mounting holes 301. The printing substrate 3 is fixedly mounted on the substrate heating plate 2 using mounting bolts that pass through the mounting holes 301. During operation, the substrate heating plate 2 continuously heats the printing substrate 3, thereby reducing the temperature difference between the printing substrate 3 and the parts, effectively preventing the parts from cracking, and ensuring the quality of the printed parts.

[0050] like Figures 1 to 6 As shown, in order to install the inflation device, a storage groove 302 is provided in the middle of the side of the printing substrate 3 away from the substrate heating plate 2. The top surface of the printing substrate 3 forms a laser printing forming area surrounding the storage groove 302. The inflation device is located in the storage groove 302. In the initial state of printing, the inflation device is lower than the laser printing forming area or at the same height as the laser printing forming area to avoid interference when printing parts.

[0051] The storage slot 302 has a square or circular structure. The inflation device is adapted to the storage slot 302, and the bottom of the inflation device is fixedly connected to the printing substrate 3. In this embodiment, the storage slot 302 has a square structure, which enables the printing of annular parts with circular or square cross-sections in the laser printing forming area of ​​the printing substrate 3.

[0052] like Figure 2 , Figures 4 to 9 As shown, the inflation device includes a deformable body and an air pump 5. The bottom of the deformable body is fixedly connected to the printing substrate 3. The air inlet of the air pump 5 is connected to an air inlet pipe 6. The air inlet end of the air inlet pipe 6 extends to the outside of the printing substrate 3. The air outlet of the air pump 5 is connected to an air outlet pipe 7. The air pump 5 is connected to the deformable body through the air outlet pipe 7.

[0053] like Figure 2 , Figures 5 to 9 , Figure 11 As shown, the deformable part has a clearance groove on the side near the printing substrate 3, and the air pump 5 is located in the clearance groove. The printing substrate 3 has an air pipe clearance hole 303 corresponding to the air pump 5, and the air inlet pipe 6 extends to the outside of the printing substrate 3 through the air pipe clearance hole 303. During the printing process of the part, after one layer of printing is completed, the air pump 5 works to inflate the deformable part, increasing the volume of the deformable part and filling the internal space of the forming cylinder 1.

[0054] like Figures 1 to 5 , Figure 7 , Figure 8 As shown in the figure, in this embodiment, the deformable part includes an inflatable airbag 4, which is made of high-temperature resistant silicone material. The high temperature resistance range of the inflatable airbag 4 is 200-300℃, ensuring that the inflatable airbag 4 is not affected by the high temperature of the substrate heating plate 2 and the printing substrate 3 during operation, and has a long service life.

[0055] like Figure 6 As shown, in one embodiment, the top of the inflatable airbag 4 is provided with an airbag top plate 8, which is horizontally fixedly installed on the top of the inflatable airbag 4; the provided airbag top plate 8 can effectively protect the inflatable airbag 4 and make the top of the inflation device flat, which is convenient for the uniform spreading of metal powder.

[0056] like Figure 9 and Figure 10 As shown in the figure, in one embodiment, the deformable body includes telescopic housings 9 that are sequentially and movably fitted together. A sealing ring 10 is provided between adjacent telescopic housings 9, and the adjacent telescopic housings 9 are slidably sealed by the sealing ring 10. When in the extended state, the outer diameter of the telescopic housing 9 away from the printing substrate 3 is larger than the outer diameter of the telescopic housing 9 close to the printing substrate 3. Thus, while realizing vertical extension and volume change, it can effectively prevent metal powder from entering between adjacent telescopic housings 9, prevent metal powder from affecting the extension and contraction of the telescopic housings 9, and extend the service life.

[0057] In one embodiment, the deformation is an integrally formed telescopic sleeve structure. The bottom of the telescopic sleeve is connected to the air pump 5 through the air outlet pipe 7. The top of the telescopic sleeve is closed. When the air pump 5 is working, the telescopic sleeve can be extended or contracted in the vertical direction.

[0058] In this embodiment, the driving device includes a drive motor fixedly installed on the forming cylinder 1, a lead screw 11 is provided below the substrate heating plate 2, the top end of the lead screw 11 is rotatably connected to the substrate heating plate 2, and a lead screw nut is provided on the forming cylinder 1 that is connected to the drive motor for transmission. The lead screw nut is threadedly connected to the lead screw 11.

[0059] In this embodiment, a lifting support plate is provided below the forming cylinder 1. The lead screw 11 is rotatably mounted between the substrate heating plate 2 and the lifting support plate using bearings. Sliding guide rods 12 are provided on both sides of the lead screw 11. A linear bearing is fixedly mounted on the forming cylinder 1. The sliding guide rods 12 are vertically slidably mounted through the linear bearings, and both ends of the sliding guide rods 12 are fixedly connected to the substrate heating plate 2 and the lifting support plate, respectively. The lead screw nut is rotatably mounted on the forming cylinder 1. A drive wheel is mounted on the output shaft of the drive motor. A driven wheel is fixedly connected to the lead screw nut. The drive wheel and the driven wheel are connected by a transmission. When the drive motor works, it drives the lead screw nut to rotate, thereby realizing the axial displacement of the lead screw 11, and thus driving the substrate heating plate 2 to reciprocate up and down within the forming cylinder 1.

[0060] This embodiment also discloses a method for additive manufacturing based on the above-described powder utilization improvement device for forming cylinders, including the following steps:

[0061] S1. Use computer-aided design software to create a 3D model of the part to be printed;

[0062] S2. Convert the 3D modeling data in step S1 into slice data, and generate a laser scanning path through the slice conversion tool.

[0063] S3. The metal powder is evenly spread on the printing substrate 3. At the same time, the substrate heating plate 2 works to heat the printing substrate 3.

[0064] S4. The laser beam scans according to a preset path, melting the metal powder into a liquid state at each scanning point to form a very small molten pool.

[0065] S5. The laser beam moves to the next scanning point and repeats the melting process of step S4 until one layer is printed.

[0066] S6. The molten metal powder adheres to the printing substrate 3 to form a solid layer;

[0067] S7. The driving device drives the heating plate 2 and the printing plate 3 of the substrate to descend by a set unit height. At the same time, the air pump 5 works to inflate the deformable body, so that the volume of the deformable body increases by a unit height, ensuring that the height of the top of the deformable body in the forming cylinder 1 remains unchanged.

[0068] S8. Spread a new layer of metal powder onto the printing substrate 3, and repeat the printing process of steps S4 and S5 to complete the printing of the next layer.

[0069] S9. The molten metal powder adheres to the previous solid layer, forming a new solid layer;

[0070] S10. Repeat steps S7, S8 and S9 until the printing of the entire part is completed.

[0071] S11. Degas the deformable part to restore it to its initial state, remove the printed part from the forming cylinder 1, discharge and clean the remaining metal powder in the forming cylinder 1, and drive the substrate heating plate 2 and the printing substrate 3 to reset.

[0072] Based on the above-mentioned device for improving the utilization rate of forming cylinder powder and additive manufacturing method, when printing and preparing ring-shaped parts or parts with low space utilization of forming cylinder 1, the parts are printed in the laser printing forming area on the printing substrate 3. The inflation expansion device extends vertically with the downward displacement of the printing substrate 3 to form a space filling part located in the forming cylinder 1, so as to replace metal powder to fill most of the middle area of ​​the part. The metal powder only needs to fill the cavity between the part and the inner wall of the forming cylinder 1 and the small space between the inflation expansion device and the inner wall of the part, thereby greatly reducing the amount of metal powder required for the laser selective melting forming of the part. The actual utilization rate of metal powder is greatly improved, and the fixed asset investment of enterprises in forming powder is effectively reduced.

[0073] It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the invention. Furthermore, it should be understood that after reading the technical description of this invention, those skilled in the art can make various alterations, modifications, and / or variations to the invention, and all such equivalent forms also fall within the scope of protection defined by the appended claims.

Claims

1. A device for improving powder utilization rate in a forming cylinder, comprising a forming cylinder, characterized in that, A substrate heating plate driven by a driving device is slidably installed in the forming cylinder along the vertical direction. A printing substrate is fixedly installed on the substrate heating plate. An inflation device is provided in the middle of the printing substrate and is located on the side of the printing substrate away from the substrate heating plate. When in working state, the inflation device gradually increases in volume along the direction away from the printing substrate. The inflation device extends vertically as the printing substrate descends to form a space filling part in the forming cylinder. A storage groove is provided in the middle of the side of the printing substrate away from the heating plate of the substrate. A laser printing forming area is formed on the top surface of the printing substrate surrounding the storage groove. The inflation device is located in the storage groove. In the initial printing state, the inflation device is lower than the laser printing forming area or at the same height as the laser printing forming area.

2. The powder utilization rate improvement device for forming cylinder according to claim 1, characterized in that, The storage slot is square or round, the inflation device is adapted to the storage slot, and the bottom of the inflation device is fixedly connected to the printing substrate.

3. The powder utilization rate improvement device for forming cylinder according to claim 1, characterized in that, The inflation device includes a deformable body and an inflation pump. The bottom of the deformable body is fixedly connected to the printed substrate. The air inlet of the inflation pump is connected to an air inlet pipe. The air inlet end of the air inlet pipe extends to the outside of the printed substrate. The air outlet of the inflation pump is connected to an air outlet pipe. The inflation pump is connected to the deformable body through the air outlet pipe.

4. The powder utilization rate improvement device for forming cylinder according to claim 3, characterized in that, The deformable part has a clearance groove on the side near the printing substrate, the air pump is located in the clearance groove, the printing substrate has an air pipe clearance hole corresponding to the air pump, and the air inlet pipe extends to the outside of the printing substrate through the air pipe clearance hole.

5. The powder utilization rate improvement device for forming cylinder according to claim 4, characterized in that, The deformation includes an inflatable airbag, which is made of high-temperature resistant silicone material and has a high temperature resistance range of 200-300℃.

6. The powder utilization rate improvement device for forming cylinder according to claim 5, characterized in that, The top of the inflatable airbag is provided with an airbag top plate, which is horizontally and fixedly installed on the top of the inflatable airbag.

7. The powder utilization rate improvement device for forming cylinder according to claim 4, characterized in that, The deformable form includes telescopic housings that are sequentially and movably fitted together. A sealing ring is provided between adjacent telescopic housings, and the adjacent telescopic housings are slidably sealed by the sealing ring. When in the extended state, the outer diameter of the telescopic housing away from the printing substrate is larger than the outer diameter of the telescopic housing close to the printing substrate.

8. The powder utilization rate improvement device for forming cylinder according to claim 4, characterized in that, The driving device includes a drive motor fixedly mounted on the forming cylinder, a lead screw is provided below the substrate heating plate, the top end of the lead screw is rotatably connected to the substrate heating plate, and a lead screw nut is provided on the forming cylinder that is drively connected to the drive motor. The lead screw nut is threadedly connected to the lead screw.

9. A method for additive manufacturing based on the powder utilization improvement device for forming cylinders according to any one of claims 1-8, characterized in that, Includes the following steps: S1. Use computer-aided design software to create a 3D model of the part to be printed; S2. Convert the 3D modeling data in step S1 into slice data, and generate a laser scanning path through the slice conversion tool. S3. The metal powder is evenly spread onto the printing substrate, and at the same time, the substrate heating plate is activated to heat the printing substrate. S4. The laser beam scans according to a preset path, melting the metal powder into a liquid state at each scanning point to form a very small molten pool. S5. The laser beam moves to the next scanning point and repeats the melting process of step S4 until one layer is printed. S6. The molten metal powder adheres to the printing substrate to form a solid layer; S7. The driving device drives the substrate heating plate and the printing substrate to descend by a set unit height. At the same time, the air pump works to inflate the deformable body, so that the volume of the deformable body increases by a unit height, ensuring that the height of the top of the deformable body in the forming cylinder remains unchanged. S8. Spread a new layer of metal powder onto the printing substrate, and repeat the printing process of steps S4 and S5 to complete the printing of the next layer. S9. The molten metal powder adheres to the previous solid layer, forming a new solid layer; S10. Repeat steps S7, S8 and S9 until the printing of the entire part is completed. S11. Depress the deformable part to restore it to its initial state, remove the printed part from the forming cylinder, discharge and clean the remaining metal powder in the forming cylinder, and drive the substrate heating plate and the printing substrate to reset.

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