Air outlet structure and metal 3D printer

Abstract

The invention relates to the field of 3D printing, and provides an air outlet structure and a metal 3D printer in order to solve the problem that the air flow uniformity in a printing breadth is difficult to guarantee by a known air outlet structure. The air outlet structure comprises a printing cabin, a first air inlet and an air return opening. The first air inlet and the air return port are distributed in the two sides of the printing cabin in the horizontal direction. The first air inlet communicates with one side of the printing cabin, is located in the position close to the bottom wall of the printing cabin and is used for blowing air into the printing cabin. The air return opening communicates with the other side of the printing cabin and is used for outward air discharging of the printing cabin. Wherein the width b0 of the first air inlet and the distance s between the air return port and the first air inlet in the horizontal direction meet a specific formula. The 3D printer has the beneficial effect that airflow in a printing breadth can be ensured to be uniform.

Description

Technical Field

[0001] This application relates to the field of 3D printing, and more particularly, to an air outlet structure and a metal 3D printer. Background Art

[0002] In metal 3D printing, such as SLM-type metal 3D printing, spatter is generated during the printing process due to the laser melting of metal powder. These spatters may adhere to the surface of the printed part, affecting the quality of the printed part.

[0003] The air outlet structure is used to blow air into the printing chamber, which can remove the spatter. However, the known air outlet structures adopt a standardized design. Although these structures can meet the basic air flow requirements, it is difficult to ensure the air flow uniformity within the printing area, which has an adverse effect on printing. Summary of the Invention

[0004] This application provides an air outlet structure and a metal 3D printer to solve the problem that the known air outlet structure is difficult to ensure the air flow uniformity within the printing area.

[0005] In a first aspect, an embodiment of this application provides an air outlet structure for a metal 3D printer. The air outlet structure includes a printing chamber, a first air inlet, and a return air outlet. The first air inlet and the return air outlet are distributed on both sides of the printing chamber in the horizontal direction; the first air inlet is connected to one side of the printing chamber and is located near the bottom wall of the printing chamber for blowing air into the printing chamber; the return air outlet is connected to the other side of the printing chamber for the printing chamber to discharge air. Among them, the width b0 of the first air inlet and the distance s between the return air outlet and the first air inlet in the horizontal direction satisfy the following formula: In the formula: u m is the axial velocity at the return air outlet, u0 is the initial velocity at the first air inlet, u m / u0 is the flow rate decay rate r, and the value of r is between 0.8 and 1.0; s is the distance between the return air outlet and the first air inlet in the horizontal direction; a is a constant, and the value of a is between 0.1 and 0.11.

[0006] In an embodiment of this application, In a possible implementation manner, the initial velocity u0 at the first air inlet is 3 - 3.2 m / s, the flow velocity u m at the return air outlet is 2.7 - 2.88 m / s, and the flow rate decay rate r is 0.9.

[0007] In a possible implementation manner, the lower edge of the first air inlet and the lower edge of the return air outlet are higher than the bottom surface of the printing chamber.

[0008] In a possible implementation, the lower edge of the first air inlet is flush with the lower edge of the air return opening, and the width of the air return opening is equal to the width b0 of the first air inlet.

[0009] In a possible implementation, the air outlet structure further includes a first air inlet passage; The first air inlet passage includes a first horizontal section, a first L-shaped section, and a first air inlet section that are connected in sequence. One end of the first horizontal section far from the first L-shaped section is connected to the first air inlet; The extending direction of the first air inlet section is perpendicular to the extending direction of the first horizontal section.

[0010] In a possible implementation, the width b1 of the first horizontal section is equal to the width b0 of the first air inlet.

[0011] In a possible implementation, the first L-shaped section includes a first connecting section and a second connecting section that are perpendicular to each other; The first air inlet section is vertically connected to the outside of the first connecting section, and the first horizontal section is vertically connected to one end of the second connecting section far from the first connecting section.

[0012] In a possible implementation, the air outlet structure further includes a second air inlet; The second air inlet is located on one side of the connecting printing chamber and near the top wall of the printing chamber, and is used to blow air into the printing chamber.

[0013] In a second aspect, an embodiment of the present application provides a metal 3D printer, which includes the aforementioned air outlet structure.

[0014] In a possible implementation, the metal 3D printer is an SLM type 3D printer. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0016] Figure 1 It is a schematic structural diagram of the air outlet structure of the embodiment of the present application.

[0017] Figure 2 It is Figure 1 a schematic diagram of the air flow model of the air outlet structure of

[0018] Figure 3 It is Figure 1 the air flow velocity simulation diagram of the air outlet structure of

[0019] Figure 4 For Figure 3 the airflow velocity simulation diagram at the A-A plane of

[0020] Figure 5 This is a schematic structural diagram of the metal 3D printer according to the embodiment of the present application.

[0021] Main component symbol description: 100 - air outlet structure; 10 - printing chamber; 11 - top wall; 12 - bottom wall; 20 - first air inlet channel; 21 - first horizontal section; 22 - first air inlet section; 221 - vertical section; 222 - flared section; 23 - first L-shaped section; 231 - first connection section; 232 - second connection section; 30 - second air inlet channel; K1 - first air inlet; K2 - second air inlet; K3 - air return port; X - horizontal direction; Z - vertical direction; 300 - metal 3D printer; 310 - printing substrate; 320 - laser assembly. Detailed implementation manners

[0022] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments.

[0023] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. When an element is considered to be "disposed on" another element, it can be directly disposed on the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are only for the purpose of illustration.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art belonging to the field of the present application. The terms used in the specification of the present application herein are only for the purpose of describing specific implementation manners, and are not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0025] Some implementation manners of the present application will be described in detail. Without conflict, the following implementation manners and the features in the implementation manners can be combined with each other.

[0026] Embodiment Refer to Figure 1, this embodiment provides an air outlet structure 100 for a metal 3D printer, such as an SLM (Selective Laser Melt) type 3D printer.

[0027] The metal 3D printer includes a laser component, a lifting component, a printing substrate, a powder spreading component, etc. Among them, the laser component is used to emit laser light. The printing substrate is connected to the lifting component and can be lifted under the drive of the lifting component. The powder spreading component is used to scrape the powder flat on the printing substrate.

[0028] During use, first, the powder spreading component lays a layer of metal powder (such as stainless steel powder) on the printing substrate. The laser light emitted by the laser component scans the metal powder along the scanning path, causing the metal powder in the scanned area to fuse. Then, the lifting component drives the printing substrate to descend by one layer. The powder spreading component lays another layer of metal powder on top of the previous layer of metal powder, and then the laser component scans and fuses it. Repeat the above operations until the metal powder fuses to obtain the required printed part.

[0029] During the printing process, the metal powder at the laser scanning surface (hereinafter referred to as the printing surface) may also be heated to generate spatter. These spatters may affect the quality of the printed part and may also affect the light transmittance and service life of the lens of the laser component.

[0030] The metal 3D printer of this embodiment further includes an air outlet structure 100. The air outlet structure 100 includes a printing chamber 10, a first air inlet K1, and an air return opening K3. The first air inlet K1 and the air return opening K3 are distributed on both sides of the printing chamber 10 along the horizontal direction X and are respectively connected to the printing chamber 10. The first air inlet K1 is used to blow air into the printing chamber 10, and the air return opening K3 is used for the printing chamber 10 to discharge air. In this way, the air flow entering from the first air inlet K1 blows out from the air return opening K3 after flowing through the printing chamber 10. This air flow can take away the spatter generated by the laser irradiation at the printing surface, reduce the influence of the spatter on the quality of the printed part, and also reduce the amount of spatter splashing onto the lens of the laser component.

[0031] The printing process performed by the aforementioned powder spreading component, printing substrate, and laser component also takes place inside the printing chamber 10. The printing surface is located at the bottom wall 12 of the printing chamber 10, and the first air inlet K1 is located near the bottom wall 12 of the printing chamber 10. In this way, the spatter splashing at the printing surface can be more easily carried away from the air return opening K3 by the air flow generated by the air intake of the first air inlet K1. The air return opening K3 is connected to the other side of the printing chamber 10.

[0032] In this embodiment, the width b0 of the first air inlet K1 and the distance s between the air return opening K3 and the first air inlet K1 along the horizontal direction X satisfy the formula: In the formula: u mis the axial velocity at the return air outlet K3, u0 is the initial velocity at the first air inlet K1, u m / u0 is the velocity attenuation rate r, which ranges from 0.8 to 1.0; s is the distance between the return air port K3 and the first air inlet K1 along the horizontal direction X, also known as the inner cabin length s; a is a constant, ranging from 0.1 to 0.11. The width b0 of the first air inlet K1 refers to its dimension along the vertical direction Z, also known as the air inlet width b0.

[0033] In this embodiment, by associating the air inlet width b0 with the inner chamber length s, the corresponding air inlet width b0 can be conveniently calculated using the inner chamber length s. After the structure and size of the print chamber 10 are determined, the air inlet width b0 can be calculated based on the inner chamber length s of the print chamber 10 using the above formula. Furthermore, based on the value of r being between 0.8-1.0 and the value of a being between 0.1-0.11, the air inlet width b0 is obtained, and the air inlet is set according to the air inlet width b0. At this time, the airflow distribution in the print chamber can be seen in Figure 2 See also Figure 2 Within the print chamber 10, the lowest layer of airflow is a laminar bottom layer S1, the middle layer is a turbulent wall-adhering layer S2, and the top layer is a free turbulent layer S3. This shows that this embodiment ensures that the air outlet structure 100 generates sufficiently uniform airflow within the print format, creating a laminar airflow within a certain height range above the print surface (i.e., the bottom layer S1 region). This airflow can stably and effectively remove most of the spatter generated by laser irradiation of metal powder on the print surface, thereby improving print quality.

[0034] In this embodiment, the constant a is set between 0.1 and 0.11 to ensure airflow uniformity. If the value of a is outside this range, the airflow velocity at the return air outlet K3 may be too small or too large, which may not meet the printing requirements.

[0035] In one embodiment, the initial flow velocity u0 at the first air inlet K1 is 3-3.2 m / s, and the flow velocity u at the return air outlet K3 is mThe velocity is 2.7 to 2.88 m / s, the flow velocity decay rate r can be taken as 0.9, and a is taken as 0.1. At this time, calculated according to the above formula, the ratio s / b0 of the inner cabin length s to the air inlet width b0 is about 13.9. At this time, if the inner cabin length s of the printing cabin 10 of a metal 3D printer is 1000 mm, when the configured air inlet width b0 is 1000 / 13.9 = 71.94 mm, in the entire printing area, the air flow in the area above the printing surface can be a laminar flow with relatively stable velocity, which is beneficial to the removal of spatter, and the air flow is not easy to blow the metal powder laid on the printing surface, ensuring the smooth progress of printing and improving the forming quality of the printed parts. At the same time, based on the above structure and dimension design, the diffusion angle of the air flow entering from the first air inlet K1 can be controlled within a suitable range, ensuring that the air flow can cover the entire printing area, while avoiding excessive diffusion of the air flow resulting in energy loss. Thus, the air outlet structure 100 of this embodiment can precisely control the air flow, improve the spatter removal effect, enhance the air flow efficiency, reduce energy consumption, and can customize and configure the first air inlet K1 with a suitable size according to the different inner cabin lengths s of different printing cabins 10, solving the limitations in the design and production of the traditional air outlet structure 100.

[0036] Continue to refer to Figure 1 , optionally, in this embodiment, the lower edges of the first air inlet K1 and the air return port K3 are higher than the bottom surface of the printing cabin 10. And, the lower edges of the first air inlet K1 and the air return port K3 are flush, and the width of the air return port K3 is equal to the width b0 of the first air inlet K1. In this way, it can further prevent the air flow blown in from the first air inlet K1 from blowing the metal powder at the printing surface, ensuring the stable progress of printing.

[0037] Optionally, the air outlet structure 100 further includes a first air inlet passage 20. The first air inlet passage 20 includes a first horizontal section 21, a first L-shaped section 23, and a first air inlet section 22 that are connected in sequence. One end of the first horizontal section 21 away from the first L-shaped section 23 is connected to the first air inlet K1. The extending direction of the first air inlet section 22 and the extending direction of the first horizontal section 21 are perpendicular to each other. The first horizontal section 21 extends along the horizontal direction X, and the first air inlet section 22 extends along the vertical direction Z. Optionally, the first air inlet section 22 includes a vertical section 221 and a flared section 222. The flared section 222 is connected between the vertical section 221 and the first L-shaped section 23 and has a structure with an increasing diameter. The first L-shaped section 23 includes a first connecting section 231 and a second connecting section 232 that are perpendicular to each other. The first air inlet section 22 is vertically connected to the outside of the first connecting section 231, and the first horizontal section 21 is vertically connected to one end of the second connecting section 232 away from the first connecting section 231. The width b1 of the first horizontal section 21 is equal to the width b0 of the first air inlet K1. In this way, the air flow blown into from the first air inlet section 22 can enter the first horizontal section 21 after multiple turns through the first L-shaped section 23, and then enter the printing chamber 10 from the first air inlet K1 after a stable flow through the first horizontal section 21, ensuring better air flow stability entering the printing chamber 10. Optionally, the length of the first horizontal section 21 along the horizontal direction X can be set to be relatively large, for example, set to be more than 30 cm. In this way, the air flow can flow stably along the horizontal direction X in the first horizontal section 21 for a long time before entering the printing chamber 10, making the air flow stability entering the printing chamber 10 better.

[0038] Refer to again Figure 1 , in this embodiment, the air outlet structure 100 further includes a second air inlet K2. The second air inlet K2 is located on the side connected to the printing chamber 10 and near the top wall 11 of the printing chamber 10, and is used to blow air into the printing chamber 10. The air inlet of the second air inlet K2 passes near the top wall of the printing chamber 10, and can blow air near the lens of the laser assembly of the metal 3D printer, which can clean the lens and reduce the possibility of splashes adhering to the lens of the laser assembly. The air outlet structure 100 further includes a second air inlet passage 30. The second air inlet passage 30 is connected to the second air inlet K2 and is used to supply air to the second air inlet K2. The structure of the second air inlet passage 30 can be similar to that of the first air inlet passage 20, including more turns and including a longer horizontal section connected to the second air inlet K2.

[0039] For the above air outlet structure 100, the air flow velocity distribution during its use can be seen in Figure 3 and Figure 4 shown in the simulation diagrams. Among them, Figure 4 is Figure 3 the air flow velocity simulation diagram at the A-A section.

[0040] As Figure 3 andFigure 4 In the air flow from the first air inlet K1 to the air return port K3, the air flow enters the first air inlet section 22 of the first air inlet passage 20 at a relatively high flow rate (about 5 m / s). During the process that the air inlet of the first air inlet section 22 enters the first horizontal section 21 through the first L-shaped section 23, the air flow makes several direction turns, then enters the printing chamber 10 from the first air inlet K1, and then blows out of the printing chamber 10 from the air return port K3 on the other side of the printing chamber 10. Among them, the flow rate of the air flow entering from the first air inlet K1 is approximately about 3 m / s, and the flow rate of the air flow blowing out from the air return port K3 is approximately 2.7 m / s. That is, within the printing width between the first air inlet K1 and the air return port K3, the flow rate of the air flow can be kept uniform and stable, which is beneficial to ensuring the printing quality.

[0041] See Figure 5 In addition, this embodiment further provides a metal 3D printer 300, and the metal 3D printer 300 is, for example, an SLM type 3D printer. The metal 3D printer 300 includes the aforementioned air outlet structure 100. The metal 3D printer 300 further includes a printing substrate 310, a laser assembly 320, etc. The printing substrate 310 is located on one side of the bottom wall 12 of the printing chamber 10 and is used to carry the printed part. The laser assembly 320 is located on one side of the top wall 11 of the printing chamber 10 and is used to emit laser light. The first air inlet K1 is used to blow air at the bottom wall 12 of the printing chamber 10, and the second air inlet K2 is used to blow air at the top wall 11 of the printing chamber 10.

[0042] The above embodiments are only used to illustrate the technical solutions of the present application rather than to limit them. Although the present application has been described in detail with reference to the above preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. An air outlet structure for a metal 3D printer, characterized in that, The air outlet structure includes: A printing chamber; and, A first air inlet and an air return opening, which are distributed on both sides of the printing chamber in the horizontal direction; the first air inlet communicates with one side of the printing chamber and is located near the bottom wall of the printing chamber for blowing air into the printing chamber; the air return opening communicates with the other side of the printing chamber for the printing chamber to discharge air to the outside; Wherein, the width b0 of the first air inlet and the distance s between the air return opening and the first air inlet in the horizontal direction satisfy the following formula: Where: u m is the axial velocity at the air return opening, u0 is the initial velocity at the first air inlet, and u m / u0 is the flow velocity decay rate r, and the value of r ranges from 0.8 to 1.0; s is the horizontal distance between the air return opening and the first air inlet; a is a constant, and the value of a ranges from 0.1 to 0.

11.

2. The air outlet structure according to claim 1, wherein: The initial flow velocity u0 at the first air inlet is 3 to 3.2 m / s, and the flow velocity u m at the air return inlet is 2.7 to 2.88 m / s, and the flow velocity decay rate r is 0.

9.

3. The air outlet structure according to claim 1, wherein: The lower edge of the first air inlet and the lower edge of the air return opening are higher than the bottom surface of the printing chamber.

4. The air outlet structure according to claim 1, wherein: The lower edge of the first air inlet and the lower edge of the air return opening are flush, and the width of the air return opening is equal to the width b0 of the first air inlet.

5. The air outlet structure according to any one of claims 1-4, wherein: The air outlet structure further includes a first air inlet passage; The first air inlet passage includes a first horizontal section, a first L-shaped section and a first air inlet section that are sequentially connected. One end of the first horizontal section far from the first L-shaped section communicates with the first air inlet; The extending direction of the first air inlet section and the extending direction of the first horizontal section are perpendicular to each other.

6. The air outlet structure according to claim 5, wherein: The width b1 of the first horizontal section is equal to the width b0 of the first air inlet.

7. The air outlet structure according to claim 6, wherein: The first L-shaped section includes a first connecting section and a second connecting section that are perpendicular to each other; The first air inlet section is vertically connected to the outside of the first connecting section, and the first horizontal section is vertically connected to one end of the second connecting section far from the first connecting section.

8. The air outlet structure according to claim 1, wherein: The air outlet structure further includes a second air inlet; The second air inlet is located on one side communicating with the printing chamber and is located near the top wall of the printing chamber for blowing air into the printing chamber.

9. A metal 3D printer, characterized in that, Including: The air outlet structure according to any one of claims 1-8.

10. The metal 3D printer according to claim 9, wherein: The metal 3D printer is an SLM type 3D printer.

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