3D printer and 3D printing method

Abstract

The application relates to the field of 3D printing technology, aims to solve the technical problem of low printing quality of some known 3D printers, and provides a 3D printer and a 3D printing method. The 3D printer comprises a printing platform, a scraper assembly, a laser generating assembly and a heat exchanger. The scraper assembly is arranged on one side of the printing platform, and the scraper assembly is used for laying printing powder on the printing platform. The laser generating assembly is used for melting the printing powder laid on the printing platform and forming a printing layer. The heat exchanger is arranged on the side of the printing platform close to the scraper assembly, and the heat exchanger is used for cooling the printing layer. The application has the beneficial effect of improving the printing quality.

Description

Technical Field

[0001] This application relates to the field of 3D printing technology, and more specifically, to 3D printers and 3D printing methods. Background Technology

[0002] Laser powder bed fusion additive manufacturing, also known as SLM (selective laser melting) printing technology, is an additive manufacturing technology that uses a laser to melt and solidify layer-by-layer metal powder to form a printed part.

[0003] Some known 3D printers have technical issues with poor print quality. Summary of the Invention

[0004] This application provides a 3D printer and a 3D printing method to solve some known technical problems related to the low printing quality of 3D printers.

[0005] This application provides a 3D printer, including a printing platform, a scraper assembly, a laser generator assembly, and a heat exchanger. The scraper assembly is disposed on one side of the printing platform and is used to spread printing powder on the printing platform. The laser generator assembly is used to melt the printing powder spread on the printing platform and form a printed layer. The heat exchanger is disposed on the side of the printing platform near the scraper assembly and is used to cool the printed layer.

[0006] According to the 3D printer of this application, after melting one printing layer, the heat exchanger can reduce the temperature of the printing layer, thereby reducing the overall temperature of the formed part. This allows the temperature of the printed part to be maintained within a certain range during the printing process, preventing the temperature of the printed part from continuously rising under the laser action of the laser generating component. This alleviates problems such as surface blackening, deformation, or powder adhesion during printing caused by overheating, thus improving print quality. Furthermore, since the cooling time of the printed part is shortened during printing and there is no need to reduce the laser power, printing efficiency can be further improved. In addition, because the heat exchanger directly cools the printed layers, the powder spreading and printing of the next layer can be performed only after the temperature of each printed layer has decreased. Compared to cooling the printed part by setting a cooler on the printing platform, the 3D printer of this application has higher cooling efficiency. Moreover, because the temperature of the printed layers decreases, the squeegee component is less likely to damage the printed layers during powder spreading, keeping the printed layers intact and thus improving print quality.

[0007] In one possible implementation: The printing platform has a forming area; the heat exchanger is movably disposed relative to the printing platform, and the moving area of ​​the heat exchanger is projected onto the printing platform to cover the forming area.

[0008] In one possible implementation: The forming area includes multiple sub-regions; the heat exchanger includes multiple heat exchange units, and the orthographic projection of the movement path of each heat exchange unit on the printing platform roughly corresponds to one of the sub-regions.

[0009] In one possible implementation: The 3D printing equipment also includes a displacement device located on one side of the printing platform; the scraper assembly is driven to the displacement device; the heat exchanger is driven to the displacement device, and along the powder spreading direction of the scraper assembly, the heat exchanger is located on one side of the forward direction of the scraper assembly.

[0010] In one possible implementation: The heat exchanger includes a semiconductor heat exchanger, which includes a cold end and a hot end. The cold end has a heat exchange surface facing the printing platform and is spaced apart from the printing layer. The hot end is connected to the side of the cold end away from the printing platform.

[0011] In one possible implementation: The 3D printing equipment also includes a heat exchange component connected to the heat exchanger, which is used to cool the heat exchanger.

[0012] In one possible implementation: The 3D printer also includes a detection component, which is located on one side of the printing platform and is used to obtain temperature distribution information of the printed layer.

[0013] This application also provides a 3D printing method applied to the aforementioned 3D printer. The 3D printing method includes: forming a printing layer; moving the heat exchanger at a preset moving speed, wherein the heat exchanger exchanges heat with the printing layer during the moving process to reduce the temperature of the printing layer; laying printing powder on the printing layer after the temperature has dropped to form a powder layer; and melting the powder layer to form the next printing layer.

[0014] In one possible implementation: The heat exchanger includes multiple heat exchange units; before moving the heat exchanger at a preset moving speed, the 3D printing method further includes: acquiring temperature distribution information of the printed layer, the temperature distribution information including multiple temperature distribution sub-intervals, each temperature distribution sub-interval corresponding to the moving path of the corresponding heat exchange unit; and obtaining the cooling power of the corresponding heat exchange unit during the moving process based on the temperature distribution sub-intervals.

[0015] In one possible implementation: The step of laying printing powder on the printed layer after the temperature drops and forming a powder layer includes: moving the doctor blade assembly synchronously during the movement of the heat exchanger, with the heat exchanger located on one side of the forward direction of the doctor blade assembly along the powder scraping direction of the doctor blade assembly; after the heat exchanger has completed the cooling of the current portion of the printed layer, the doctor blade assembly lays printing powder on the portion of the printed layer, and so on until the powder layer is laid. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of a 3D printer according to an embodiment of this application.

[0018] Figure 2 This is a partial structural diagram of a 3D printer according to an embodiment of this application.

[0019] Figure 3 This is a top view of a partial structure of a 3D printer according to an embodiment of this application.

[0020] Figure 4 This is an exploded structural diagram of a printing platform, printing layer, and heat exchanger according to an embodiment of this application.

[0021] Figure 5 This is a flowchart of a 3D printing method according to an embodiment of this application.

[0022] Explanation of key component symbols: 3D printer 100 Printing Pod 10 Printing cylinder 20 Printing platform 30 Scraper assembly 40 Laser Generator Component 50 Laser generator 51 Heat exchanger 60 Semiconductor heat exchanger 60a Cold end 61 Hot end 62 Displacement device 71 Item 72 Lifting drive component 80 Heat exchanger assembly 90 Heat exchange chamber 91 Connecting tube 92 Cooling component 93 Printing cavity Q1 Containment cavity Q2 Molding area A1 Subregion A11 Printing layer 200 Powder layer 300 First direction X Second direction Y Third direction Z Radiation surface P The following detailed description, in conjunction with the accompanying drawings, will further illustrate this application. Detailed Implementation

[0023] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0024] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. When a component is said to be "set on" another component, it can be directly set on the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "or / and" as used herein includes any and all combinations of one or more of the associated listed items.

[0026] Some embodiments of this application are described in detail. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0027] See Figure 1 This embodiment provides a 3D printer 100, including a printing chamber 10, a printing cylinder 20, a lifting drive component 80, a printing platform 30, a scraper assembly 40, a laser generating assembly 50, and a heat exchanger 60.

[0028] The printing chamber 10 defines the printing cavity Q1, and the printing cylinder 20, printing platform 30, scraper assembly 40, laser generator assembly 50 and heat exchanger 60 are all located in the printing cavity Q1.

[0029] The printing cylinder 20 is provided with a receiving cavity Q2, and the lifting drive component 80 is located in the receiving cavity Q2. The printing platform 30 is connected to the lifting drive component 80 and can move under the drive of the lifting drive component 80.

[0030] A doctor blade assembly 40 is located on the side of the printing platform 30 opposite to the receiving cavity Q2. The doctor blade assembly 40 is used to spread printing powder on the printing platform 30 and form a powder layer 300. A laser generating assembly 50 is located on the side of the doctor blade assembly 40 opposite to the printing cylinder 20. The laser generating assembly 50 is used to melt the printing powder (i.e., powder layer 300) spread on the printing platform 30 and form a printed layer 200. A heat exchanger 60 is located on the side of the printing platform 30 near the doctor blade assembly 40. The heat exchanger 60 is used to cool the printed layer 200.

[0031] According to the 3D printer 100 of this application, after melting one printing layer 200, the heat exchanger 60 can reduce the temperature of the printing layer 200, thereby reducing the overall temperature of the formed part. This allows the temperature of the printed part to be maintained within a certain range during the printing process, preventing the temperature of the printed part from continuously rising under the laser action of the laser generating component 50. This alleviates problems such as surface blackening, deformation, or powder adhesion during printing caused by overheating, thus improving print quality. Furthermore, since the cooling time of the printed part is shortened during printing and there is no need to reduce the laser power, printing efficiency can be further improved. In addition, since the heat exchanger 60 directly cools the printed layer 200, the powder spreading and printing of the next printing layer 200 can be performed only after the temperature of each printing layer 200 has decreased. Compared with the method of cooling the printed part by setting a cooler on the printing platform 30, the cooling efficiency of the 3D printer 100 of this application is higher. Furthermore, as the temperature of the printed layer 200 decreases, the squeegee assembly 40 is less likely to damage the printed layer 200 that has already been printed during the powder spreading process, thus keeping the printed layer 200 intact and improving print quality.

[0032] In some embodiments, see Figure 2The printing platform 30 has a forming area A1. Forming area A1 refers to the area on the printing platform 30 used for laying the powder layer 300 and forming the printed layer 200. The orthographic projection of the part to be printed on the printing platform 30 lies within the boundary of forming area A1. A heat exchanger 60 is movable relative to the printing platform 30. Thus, the heat exchanger 60 can cool the printed layer 200 during movement, thereby reducing the heat exchange area of ​​the heat exchanger 60 and lowering its cost. The projection of the moving area of ​​the heat exchanger 60 onto the printing platform 30 covers forming area A1. This ensures that the heat exchanger 60 can cool all parts of the topmost printed layer 200 on the printing platform 30 during movement, thereby further improving print quality.

[0033] In some embodiments, see Figure 2 The forming area A1 includes multiple sub-areas A11. The heat exchanger 60 includes multiple heat exchange units, and the orthographic projection of the movement path of each heat exchange unit on the printing platform 30 roughly corresponds to a sub-area A11.

[0034] Thus, during the process of moving the heat exchanger 60, each heat exchange unit can cool a portion of the printed layer 200 on the corresponding sub-region A11, enabling the heat exchange units to perform independent cooling operations on the corresponding portions of the printed layer 200, so that the temperatures of the various portions of the printed layer 200 after cooling are relatively close, improving the temperature uniformity of the printed layer 200 and further improving the printing quality.

[0035] In some implementations, see Figure 2 Multiple heat exchange units are arranged along a first direction X. Adjacent heat exchange units may be in contact with each other or spaced apart. Multiple sub-regions A11 extend along the first direction X. Multiple sub-regions A11 are adjacent to each other along a second direction Y. In other embodiments, the arrangement of the multiple sub-regions A11 can also be determined based on the arrangement and movement path of the multiple heat exchange units; for example, the sub-regions A11 may extend in an S-shape or an irregular shape.

[0036] In some embodiments, see Figure 1 The 3D printer 100 also includes a detection element 72. The detection element 72 is located on one side of the printing platform 30 and is used to acquire temperature distribution information of the printed layer 200.

[0037] Optionally, the detection element 72 may be configured as a thermal imager.

[0038] In some embodiments, the 3D printer 100 further includes a controller. The controller is communicatively connected to the detection element 72. The controller is connected to the detection element 72 via a cable or wirelessly. The controller can acquire temperature distribution information and, based on a preset temperature of the printed layer 200, obtain the actual temperature difference between the real-time temperature at various points on the printed layer 200 and the preset temperature. It then calculates the cooling capacity required to adjust the real-time temperature at various points on the printed layer 200 to the preset temperature according to a preset adjustment strategy, and calculates the corresponding cooling power of the heat exchanger 60 based on the obtained cooling capacity. Subsequently, during the movement of the heat exchanger 60 driven by the displacement device 71, the controller controls the cooling power of the heat exchanger 60 in real time to ensure that the real-time temperature at various points on the printed layer 200 is approximately the same as the preset temperature after heat exchange.

[0039] Specifically, the cooling power of the heat exchanger 60 corresponding to the part with a larger real-time temperature difference is greater than the cooling power of the heat exchanger 60 corresponding to the part with a smaller real-time temperature difference.

[0040] In some embodiments, see Figure 1 The 3D printing equipment also includes a heat exchange assembly 90. The heat exchange assembly 90 is connected to the heat exchanger 60 and is used to cool the heat exchanger 60.

[0041] After the heat exchanger 60 cools the printed layer 200, the temperature of the heat exchanger 60 rises. The heat exchange component 90 cools the heat exchanger 60, which ensures that the heat exchanger 60 can efficiently cool the next printed layer 200. This ensures that the heat exchanger 60 can cool the previous printed layer 200 in each powder spreading process, thereby further improving printing efficiency.

[0042] In some embodiments, see Figure 2 and Figure 3 The heat exchanger 60 includes a semiconductor heat exchanger 60a. The semiconductor heat exchanger 60a includes a cold end 61 and a hot end 62. The cold end 61 has a heat exchange surface facing the printing platform 30 and is spaced apart from the printing layer 200. The hot end 62 is connected to the side of the cold end 61 away from the printing platform 30.

[0043] The semiconductor heat exchanger 60a includes multiple cold ends 61 and multiple hot ends 62. The number of cold ends 61 is the same as the number of hot ends 62. Each cold end 61 is connected to a corresponding hot end 62, forming a heat exchange unit.

[0044] In some embodiments, see Figure 3 The heat exchanger 60 has a radiating surface P. The distance between the radiating surface P and the doctor blade assembly 40 and the previous printed layer 200 is H1. The radiating surface P can be the surface of the cold end 61 facing the printing platform 30. The distance between the doctor blade assembly 40 and the previous printed layer 200 is H2. H1 ≥ H2.

[0045] Wherein, 1mm≤H1≤10mm. H1 can be determined based on relevant parameters such as the thickness of the printing layer 200 and the powder layer 300. H1 can be set to any one of 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm or 10mm.

[0046] In some embodiments, the heat exchange assembly 90 is connected to the side of the hot end 62 away from the cold end 61, and the heat exchange assembly 90 is used to cool the hot end 62.

[0047] In some implementations, see Figure 1 The heat exchange assembly 90 includes a heat exchange chamber 91, a connecting pipe 92, and a cooling element 93. The heat exchange chamber 91 is connected to the hot end 62 and is filled with a heat exchange medium. The heat exchange medium can be a gaseous or liquid medium. One end of the connecting pipe 92 is connected to the heat exchange chamber 91, and the connecting pipe 92 is used to transport the heat exchange medium. The cooling element 93 is connected to the other end of the connecting pipe 92 and is used to cool the heat exchange medium. The heat exchange medium in the heat exchange chamber 91 exchanges heat with the hot end 62 to cool the hot end 62. The heated heat exchange medium moves through the connecting pipe 92 to the cooling element 93, where it is cooled. The cooled heat exchange medium then moves back through the connecting pipe 92 to the heat exchange chamber 91 to cool the hot end 62.

[0048] In some implementations, see Figure 1 The cooling element 93 is located outside the printing chamber 10. The connecting pipe 92 passes through the printing chamber 10. One end of the connecting pipe 92 is connected to the heat exchange chamber 91, and the other end of the connecting pipe 92 is connected to the cooling element 93. In this way, the operation of the cooling element 93 can be prevented from affecting the temperature inside the printing chamber 10.

[0049] In some embodiments, the cooling element 93 may be configured as a liquid cooling plate, a fan, etc.

[0050] In some embodiments, see Figure 1 The laser generating assembly 50 includes multiple laser generators 51. The multiple laser generators 51 are used to emit multiple laser beams to improve printing efficiency.

[0051] In some embodiments, see Figure 4 The 3D printing equipment also includes a displacement device 71. The displacement device 71 is located on one side of the printing platform 30. A scraper assembly 40 is drivenly connected to the displacement device 71. A heat exchanger 60 is drivenly connected to the displacement device 71, and is located on one side of the scraper assembly 40 in the forward direction along the powder spreading direction of the scraper assembly 40. The powder spreading direction of the scraper assembly 40 is parallel to the first direction X.

[0052] In this way, the heat exchanger 60 can move synchronously with the doctor blade assembly 40. After the heat exchanger 60 has cooled a portion of the current printed layer 200, the doctor blade assembly 40 then moves to that portion of the current printed layer 200 and lays powder on it. Thus, after the heat exchanger 60 completes the heat exchange action of the printed layer 200, the doctor blade assembly 40 has also finished laying the powder layer 300 on the current printed layer 200, making it easier for the laser generating assembly 50 to melt the powder layer 300 into the next printed layer 200. This further improves printing efficiency.

[0053] Optionally, the heat exchanger 60 may be drivenly connected to the displacement device 71. The heat exchanger 60 may also be connected to the scraper assembly 40 to move synchronously with the scraper assembly 40.

[0054] Optionally, the displacement device 71 can be configured as an electric push rod, cylinder, motor or lead screw assembly, etc., and the displacement device 71 can also be configured as a multi-axis robot.

[0055] See Figure 5 This application also provides a 3D printing method applied to the 3D printer 100 as described above. The 3D printing method includes the following steps: Step 101: Form a printing layer 200.

[0056] In some embodiments, the formed printed layer 200 can be a first printed layer 200 or a printed layer 200 in a subsequent printing process. The printed layer 200 is formed by the squeegee assembly 40 spreading printing powder on the surface of the printing platform 30 or the previous printed layer 200 to form a powder layer 300. The laser generating assembly 50 emits a laser and melts the powder layer 300, which then cools and solidifies to form the printed layer 200.

[0057] Step 102: Move the heat exchanger 60 at a preset moving speed. During the movement, the heat exchanger 60 exchanges heat with the printing layer 200 and reduces the temperature of the printing layer 200.

[0058] Step 103: Spread printing powder on the cooled printing layer 200 to form a powder layer 300.

[0059] The heat exchanger 60 can be driven to move by an independent drive structure, or it can move synchronously with the scraper assembly 40.

[0060] Step 104: Melt the powder layer 300 to form the next printed layer 200.

[0061] Compared with related technologies, the 3D printing method of this application can improve printing quality.

[0062] In some embodiments, before moving the heat exchanger 60 at a preset moving speed, the 3D printing method further includes: acquiring temperature distribution information of the printing layer 200, the temperature distribution information including multiple temperature distribution sub-intervals, each temperature distribution sub-interval corresponding to the moving path of the corresponding heat exchange unit; and obtaining the cooling power of the corresponding heat exchange unit during the moving process based on the temperature distribution sub-intervals.

[0063] This ensures that the real-time temperature of each part of the printing layer 200 is approximately the same as the preset temperature after the heat exchange is completed, thereby improving the printing quality.

[0064] In some embodiments, the step of laying printing powder on the printed layer 200 after the temperature has dropped and forming a powder layer 300 includes: simultaneously moving the scraper assembly 40 while moving the heat exchanger 60, with the heat exchanger 60 located on one side of the forward direction of the scraper assembly 40 along the powder scraping direction of the scraper assembly 40; after the heat exchanger 60 has completed the cooling of a portion of the current printed layer 200, the scraper assembly 40 lays printing powder on a portion of the printed layer 200, and so on until the powder layer 300 is laid.

[0065] In this way, the heat exchanger 60 can move synchronously with the doctor blade assembly 40. After the heat exchanger 60 has cooled a portion of the current printed layer 200, the doctor blade assembly 40 then moves to that portion of the current printed layer 200 and lays powder on it. Thus, after the heat exchanger 60 completes the heat exchange action of the printed layer 200, the doctor blade assembly 40 has also finished laying the powder layer 300 on the current printed layer 200, making it easier for the laser generating assembly 50 to melt the powder layer 300 into the next printed layer 200. This further improves printing efficiency.

[0066] The above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to the above preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of this application should not depart from the spirit and scope of the technical solutions of this application.

Claims

1. A 3D printer, characterized in that, include: Printing platform; A scraper assembly is disposed on one side of the printing platform and is used to spread printing powder on the printing platform; A laser generating component is used to melt the printing powder laid on the printing platform and form a printing layer; as well as A heat exchanger is located on the printing platform near the doctor blade assembly and is used to cool the printed layer.

2. The 3D printer according to claim 1, characterized in that: The printing platform has a forming area; The heat exchanger is movably disposed relative to the printing platform, and the moving area of ​​the heat exchanger is projected onto the printing platform to cover the forming area.

3. The 3D printer according to claim 2, characterized in that: The forming area includes multiple sub-regions; The heat exchanger includes multiple heat exchange units, and the orthographic projection of the movement path of each heat exchange unit on the printing platform roughly corresponds to one of the sub-regions.

4. The 3D printer according to claim 1, characterized in that: The 3D printing equipment also includes a displacement device, which is located on one side of the printing platform; The scraper assembly is driven by the displacement device; The heat exchanger is drivenly connected to the displacement device, and is located on one side of the forward direction of the scraper assembly along the powder spreading direction of the scraper assembly.

5. The 3D printer according to any one of claims 1 to 4, characterized in that: The heat exchanger includes a semiconductor heat exchanger, which includes a cold end and a hot end. The cold end has a heat exchange surface facing the printing platform, and the heat exchange surface is spaced apart from the printing layer. The hot end is connected to the side of the cold end away from the printing platform.

6. The 3D printer according to any one of claims 1 to 4, characterized in that: The 3D printing equipment also includes a heat exchange component connected to the heat exchanger, which is used to cool the heat exchanger.

7. The 3D printer according to any one of claims 1 to 4, characterized in that: The 3D printer also includes a detection component, which is located on one side of the printing platform and is used to obtain temperature distribution information of the printed layer.

8. A 3D printing method, characterized in that, The 3D printing method, applied to any one of claims 1 to 7, comprises: Form a printing layer; The heat exchanger moves at a preset speed, and during the movement, the heat exchanger exchanges heat with the printed layer to reduce the temperature of the printed layer. Printing powder is laid on the printed layer after the temperature drops, forming a powder layer; The powder layer is melted to form the next printed layer.

9. The 3D printing method according to claim 8, characterized in that: The heat exchanger includes multiple heat exchange units; Before moving the heat exchanger at a preset moving speed, the 3D printing method further includes: The temperature distribution information of the printed layer is obtained. The temperature distribution information includes multiple columns of temperature distribution sub-intervals, and each temperature distribution sub-interval corresponds to the movement path of the corresponding heat exchange unit. The cooling power of the heat exchange unit during its movement is obtained based on the temperature distribution sub-interval.

10. The 3D printing method according to claim 8, characterized in that: The step of depositing printing powder onto the printed layer after the temperature has dropped, and forming a powder layer, includes: During the movement of the heat exchanger, the scraper assembly is moved synchronously, and the heat exchanger is located on one side of the forward direction of the scraper assembly along the scraping direction of the scraper assembly. After the heat exchanger has cooled down a portion of the current printed layer, the scraper assembly lays printing powder on that portion of the printed layer, and this process is repeated until the powder layer is completely laid.

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