Air outlet structure and metal 3D printer

Abstract

The present application relates to the field of 3D printing, and aims to solve the problem that known air outlet structures are difficult to ensure uniform airflow within the printing format, and to provide an air outlet structure and a metal 3D printer. Among them, the air outlet structure includes a printing cabin, a first air inlet and a return air outlet. The first air inlet and the return air outlet are horizontally distributed on both sides of the printing cabin; the first air inlet is connected to one side of the printing cabin and is located near the bottom wall of the printing cabin, for blowing air into the printing cabin; the return air outlet is connected to the other side of the printing cabin, for blowing air out of the printing cabin. Among them, the width b0 of the first air inlet and the distance s between the return air inlet and the first air inlet in the horizontal direction meet a specific formula. The beneficial effect of the present application is that it can ensure uniform airflow within the printing format.

Description

Technical Field

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

[0002] Metal 3D printing, such as SLM-based metal 3D printing, produces spatter during the printing process due to the laser melting of metal powder. This spatter may adhere to the surface of the printed part and affect the quality of the printed part.

[0003] The air outlet structure is used to blow air into the print chamber and remove splashing debris. However, conventional air outlet structures use standardized designs. While these structures can meet basic air flow requirements, they struggle to ensure uniform airflow across the print surface, adversely affecting printing. Summary of the Invention

[0004] The present application provides an air outlet structure and a metal 3D printer to solve the problem that the conventional air outlet structure is difficult to ensure the uniformity of air flow within the printing format.

[0005] In a first aspect, an embodiment of the present application provides an air outlet structure for a metal 3D printer, wherein the air outlet structure includes a print chamber, a first air inlet, and a return air outlet. The first air inlet and the return air outlet are horizontally distributed on both sides of the print chamber; the first air inlet is connected to one side of the print chamber and is located near the bottom wall of the print chamber, and is used to blow air into the print chamber; the return air outlet is connected to the other side of the print chamber and is used to blow air out of the print chamber. The width b0 of the first air inlet and the horizontal distance s between the return air outlet and the first air inlet satisfy the following formula:

[0006]

[0007] Where: 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 velocity attenuation rate r, and the value of r is between 0.8 and 1.0; s is the horizontal distance between the return air outlet and the first air inlet; a is a constant, and the value of a is between 0.1 and 0.11.

[0008] In the embodiments of this application,

[0009] In a possible embodiment, the initial flow velocity u0 at the first air inlet is 3-3.2 m / s, and the flow velocity u at the return air outlet is m It is 2.7~2.88m / s, and the flow velocity attenuation rate r is 0.9.

[0010] In a possible implementation, 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.

[0011] In a possible implementation, the lower edge of the first air inlet is flush with the lower edge of the return air outlet, and the width of the return air outlet is equal to the width b0 of the first air inlet.

[0012] In a possible implementation, the air outlet structure further includes a first air inlet channel;

[0013] The first air inlet channel comprises a first horizontal section, a first L-shaped section and a first air inlet section which are connected in sequence, and an end of the first horizontal section away from the first L-shaped section is connected to the first air inlet;

[0014] An extending direction of the first air inlet section and an extending direction of the first horizontal section are perpendicular to each other.

[0015] In a possible implementation, the width b1 of the first horizontal segment is equal to the width b0 of the first air inlet.

[0016] In one possible embodiment, the first L-shaped segment includes a first connecting segment and a second connecting segment that are perpendicular to each other;

[0017] The first air inlet section is vertically connected to the outer side of the first connecting section, and the first horizontal section is vertically connected to the second connecting section away from one end of the first connecting section.

[0018] In a possible implementation, the air outlet structure further includes a second air inlet;

[0019] The second air inlet is located on a side connected to the printing chamber and close to the top wall of the printing chamber, and is used to blow air into the printing chamber.

[0020] In a second aspect, an embodiment of the present application provides a metal 3D printer comprising the aforementioned air outlet structure.

[0021] In one possible implementation, the metal 3D printer is an SLM 3D printer. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 This is a structural diagram of the air outlet structure of an embodiment of the present application.

[0024] Figure 2 for Figure 1 Schematic diagram of the airflow model of the air outlet structure from the first air inlet to the return air outlet.

[0025] Figure 3 for Figure 1 Simulation diagram of air flow velocity of the air outlet structure.

[0026] Figure 4 for Figure 3 Simulation diagram of airflow velocity at the AA surface.

[0027] Figure 5 This is a schematic structural diagram of a metal 3D printer according to an embodiment of the present application.

[0028] Explanation of the main component symbols: 100-air outlet structure; 10-printing cabin; 11-top wall; 12-bottom wall; 20-first air inlet channel; 21-first horizontal section; 22-first air inlet section; 221-vertical section; 222-expanding section; 23-first L-shaped section; 231-first connecting section; 232-second connecting section; 30-second air inlet channel; K1-first air inlet; K2-second air inlet; K3-return air outlet; X-horizontal direction; Z-vertical direction; 300-metal 3D printer; 310-printing substrate; 320-laser assembly. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0030] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may also be an element centered therein. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may also be an element centered therein. When an element is considered to be "set on" another element, it may be directly set on the other element or there may also be an element centered therein. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" as used herein includes any and all combinations of one or more of the relevant listed items.

[0032] Some embodiments of the present application are described in detail. In the absence of conflict, the following embodiments and features of the embodiments can be combined with each other.

[0033] Example

[0034] See also Figure 1 This embodiment provides an air outlet structure 100 for a metal 3D printer, such as an SLM (Selective Laser Melt) 3D printer.

[0035] This metal 3D printer includes a laser assembly, a lift assembly, a printing base, and a powder spreading assembly. The laser assembly emits laser light, while the printing base is connected to the lift assembly and can be raised and lowered by the lift assembly. The powder spreading assembly is used to spread powder evenly on the printing base.

[0036] During use, the powder spreading assembly first lays a layer of metal powder (such as stainless steel powder) on the print substrate. The laser assembly then scans the metal powder along a scanning path, fusing the powder in the scanned area. The lifting assembly then lowers the print substrate one level, and the powder spreading assembly lays another layer of metal powder on top of the previous layer. The laser assembly then scans and fuses the powder. This process is repeated until the metal powder is fused to form the desired print.

[0037] During the printing process, the metal powder on the laser scanning surface (hereinafter referred to as the printing surface) may be heated and produce splashes, which may affect the quality of the printed part and may also affect the transmittance and service life of the lens of the laser component.

[0038] The metal 3D printer of this embodiment also includes an air outlet structure 100. The air outlet structure 100 includes a print chamber 10, a first air inlet K1, and a return air outlet K3. The first air inlet K1 and the return air outlet K3 are distributed on both sides of the print chamber 10 along the horizontal direction X and are respectively connected to the print chamber 10. The first air inlet K1 is used to blow air into the print chamber 10, and the return air outlet K3 is used to blow air out of the print chamber 10. In this way, the airflow entering from the first air inlet K1 is blown out from the return air outlet K3 after flowing through the print chamber 10. This airflow can carry away the splashes generated by laser irradiation on the printing surface, reducing the impact of the splashes on the quality of the printed part and also reducing the amount of splashes that splash onto the lens of the laser assembly.

[0039] The printing process performed by the aforementioned powder spreading assembly, printing substrate, and laser assembly also occurs within the print chamber 10. The printing surface is located on the bottom wall 12 of the print chamber 10, and the first air inlet K1 is located near the bottom wall 12 of the print chamber 10. This allows any splatter from the printing surface to be easily carried away from the return air port K3 by the airflow generated by the first air inlet K1. The return air port K3 connects to the other side of the print chamber 10.

[0040] In this embodiment, the width b0 of the first air inlet K1 and the distance s between the return air outlet K3 and the first air inlet K1 along the horizontal direction X satisfy the formula:

[0041]

[0042] Where: u m is 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.

[0043] 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.

[0044] 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.

[0045] 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 mIt is 2.7~2.88m / s, and the flow rate attenuation rate r can be taken as 0.9. The value of a is 0.1. At this time, according to the above formula, the ratio s / b0 of the inner cabin length s and the air inlet width b0 is approximately 13.9. At this time, if the inner cabin length s of the printing cabin 10 of a metal 3D printer is 1000mm, then when the configured air inlet width b0 is 1000 / 13.9=71.94mm, within the entire printing format, the airflow in the area above the printing surface can be laminar flow with a relatively stable speed, which is conducive to the removal of splashes, and the airflow is not easy to blow the metal powder laid on the printing surface, ensuring smooth printing and improving the molding quality of the printed parts. At the same time, based on the design of the above structure and size, the diffusion angle of the airflow entering the first air inlet K1 can be controlled within an appropriate range to ensure that the airflow can cover the entire printing format while avoiding energy loss caused by excessive diffusion of the airflow. Therefore, the air outlet structure 100 of this embodiment can precisely control the air flow, improve the splash removal effect, enhance the air flow efficiency, reduce energy consumption, and can customize the first air inlet K1 of appropriate size according to the different inner cabin lengths s of different printing cabins 10, thereby solving the limitations of the traditional air outlet structure 100 in design and production.

[0046] Continue to see Figure 1 Optionally, in this embodiment, the lower edges of the first air inlet K1 and the return air outlet K3 are higher than the bottom surface of the print chamber 10. Furthermore, the lower edges of the first air inlet K1 and the return air outlet K3 are flush, and the width of the return air outlet K3 is equal to the width b0 of the first air inlet K1. This further prevents the airflow from the first air inlet K1 from moving metal powder on the printing surface, ensuring stable printing.

[0047] Optionally, the air outlet structure 100 also includes a first air inlet channel 20. The first air inlet channel 20 includes a first horizontal section 21, a first L-shaped section 23, and a first air inlet section 22, which are connected in sequence. The end of the first horizontal section 21 away from the first L-shaped section 23 is connected to the first air inlet K1. The extension direction of the first air inlet section 22 and the extension 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 an enlarged diameter structure. The first L-shaped section 23 includes a first connecting section 231 and a second connecting section 232, which 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 the 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. This allows the airflow entering the first air inlet section 22 to make multiple turns through the first L-shaped section 23 before entering the first horizontal section 21. After flowing smoothly through the first horizontal section 21, the airflow enters the print chamber 10 through the first air inlet K1, ensuring greater airflow stability. Optionally, the length of the first horizontal section 21 along the horizontal direction X can be increased, for example, to greater than 30 cm. This allows the airflow to flow smoothly within the first horizontal section 21 along the horizontal direction X for an extended period before entering the print chamber 10, further enhancing airflow stability.

[0048] See again Figure 1 In this embodiment, the air outlet structure 100 also includes a second air inlet K2. The second air inlet K2 is located on a side connected to the printing chamber 10 and is located near the top wall 11 of the printing chamber 10, and is used to blow air into the printing chamber 10. The air from 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, thereby cleaning the lens and reducing the possibility of splashes adhering to the lens of the laser assembly. The air outlet structure 100 also includes a second air inlet channel 30, which 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 channel 30 can be similar to that of the first air inlet channel 20, including more turns, and including a longer horizontal section connected to the second air inlet K2.

[0049] Regarding the above-mentioned air outlet structure 100, the air flow velocity distribution during use can be seen in Figure 3 and Figure 4 The simulation diagram shown is shown. Figure 4 for Figure 3 Simulation diagram of air flow velocity at section AA.

[0050] like Figure 3 and Figure 4 The airflow from the first air inlet K1 to the return air outlet K3 enters the first air inlet section 22 of the first air inlet channel 20 at a relatively high velocity (e.g., approximately 5 m / s). The airflow from the first air inlet section 22 undergoes several directional changes as it passes through the first L-shaped section 23 and enters the first horizontal section 21. The airflow then enters the print chamber 10 through the first air inlet K1 and is then blown out of the print chamber 10 through the return air outlet K3 on the other side of the print chamber 10. The velocity of the airflow entering from the first air inlet K1 is approximately 3 m / s, while the velocity of the airflow blowing out from the return air outlet K3 is approximately 2.7 m / s. In other words, the airflow velocity remains uniform and stable within the printing area between the first air inlet K1 and the return air outlet K3, which helps ensure print quality.

[0051] See also Figure 5 This embodiment also provides a metal 3D printer 300, which is, for example, an SLM 3D printer. The metal 3D printer 300 includes the aforementioned air outlet structure 100. The metal 3D printer 300 also includes a printing base plate 310, a laser assembly 320, and the like. The printing base plate 310 is located on the bottom wall 12 of the printing chamber 10 and is used to support the printed workpiece. The laser assembly 320 is located on 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 to the bottom wall 12 of the printing chamber 10, and the second air inlet K2 is used to blow air to the top wall 11 of the printing chamber 10.

[0052] The above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit the present application. Although the present application has been described in detail with reference to the above preferred embodiments, those skilled in the art should understand that modifications or equivalent replacements of the technical solutions of the present application should not depart 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: Printing cabin; and, A first air inlet and an air return port are horizontally distributed on both sides of the print chamber; the first air inlet is connected to one side of the print chamber and is located near the bottom wall of the print chamber, for blowing air into the print chamber; the air return port is connected to the other side of the print chamber, for blowing air out of the print chamber; The width b0 of the first air inlet and the horizontal distance s between the return air outlet and the first air inlet satisfy the following formula: Where: 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 velocity attenuation rate r, and r is between 0.8 and 1.0; s is the horizontal distance between the return air outlet and the first air inlet; a is a constant, and a is between 0.1 and 0.11; The air outlet structure further includes a first air inlet channel; The first air inlet channel includes a first horizontal section, a first L-shaped section and a first air inlet section that are connected in sequence, and an end of the first horizontal section away from the first L-shaped section is connected to the first air inlet; An extending direction of the first air inlet section and an extending direction of the first horizontal section are perpendicular to each other.

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

9.

3. The air outlet structure according to claim 1, characterized in that: 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.

4. The air outlet structure according to claim 1, characterized in that: The lower edge of the first air inlet is flush with the lower edge of the return air outlet, and the width of the return air outlet is equal to the width b0 of the first air inlet.

5. The air outlet structure according to claim 1, characterized in that: The width b1 of the first horizontal section is equal to the width b0 of the first air inlet.

6. The air outlet structure according to claim 5, characterized in that: 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 outer side of the first connecting section, and the first horizontal section is vertically connected to the second connecting section away from one end of the first connecting section.

7. The air outlet structure according to claim 1, characterized in that: The air outlet structure further includes a second air inlet; The second air inlet is located on a side connected to the printing chamber and close to the top wall of the printing chamber, and is used for blowing air into the printing chamber.

8. A metal 3D printer, characterized in that: include: The air outlet structure according to any one of claims 1 to 7.

9. The metal 3D printer according to claim 8, characterized in that: The metal 3D printer is an SLM type 3D printer.

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