Device for preventing oxidization of melting deposition

Abstract

An anti-oxidation device for a metal 3D printing additive part is provided. The anti-oxidation device according to the present invention includes a main nozzle having a main passage and a powder passage for supplying metal powder to form an additive part of a material, and an anti-oxidation nozzle coupled to the upper end of the main nozzle and for additionally spraying a second shielding gas around the additive part even when the additive part solidifies after the irradiation of the laser beam is completed.

Description

Technology Field

[0001] The present invention relates to an anti-oxidation device for a metal 3D printed laminate. Background Technology

[0002] Generally, metal 3D printing technology is a technology that manufactures three-dimensional shapes by consistently melting metal powder and layering it.

[0003] Metal 3D printing technology using metal powder is broadly divided into two methods: Powder Bed Fusion (PBF) and Direct Energy Deposition (DED).

[0004] Among these, the DED metal 3D printing process is a technology that melts and deposits metal powder by spraying it directly into the laser melting zone.

[0005] In other words, in the DED metal 3D printing process, melting occurs the moment the central laser beam reaches the stacking plate, and the desired stacking part is formed by spraying metal powder into this molten pool.

[0006] At this time, argon gas that prevents oxidation is injected through a nozzle around the laser beam. However, since the argon gas injected from the conventional nozzle only shields the local area where the laser beam is irradiated, the shielding of the solidified laminate after the nozzle is moved is insufficient.

[0007] In particular, when using iron-based and nickel-based metal powders and applying them to the DED metal 3D printing process, sufficient material properties could be secured with only local shielding.

[0008] However, when titanium and aluminum-based metal powders are applied to the DED metal 3D printing process, the reactivity of the material with oxygen is very high, so the oxygen concentration in the layer increases.

[0009] As such, while the strength of the laminated section with increased oxygen concentration rises, the elongation is significantly lower, making it difficult to secure the desired mechanical properties. The problem to be solved

[0010] The present invention aims to provide an oxidation prevention device for molten laminates that can continuously prevent oxidation of the laminated portion even during solidification after laser irradiation is completed, and is applicable even to materials that have a high reactivity with oxygen compared to iron. means of solving the problem

[0011] An oxidation prevention device for a molten laminate according to one embodiment of the present invention may include a main nozzle having a main passage through which a laser beam and a first shielding gas pass, and a powder passage disposed outside the main passage for supplying metal powder to form a laminate of the material.

[0012] The anti-oxidation device may include an anti-oxidation nozzle coupled to the upper part of the main nozzle and for additionally spraying a second shielding gas around the laminated part even when the laminated part solidifies after the laser beam irradiation is completed.

[0013] A gas guide plate may be installed at the bottom of the anti-oxidation nozzle to guide the second shielding gas to the area around the laminate.

[0014] The anti-oxidation nozzle may include a cylindrical nozzle body coupled to the outer surface of a main nozzle and having a spray portion for spraying a second shielding gas, and an inlet portion disposed on the outer surface of the nozzle body for introducing the second shielding gas into the spray portion.

[0015] A pressure regulating membrane for regulating the pressure of the second shielding gas may be installed in the injection section.

[0016] The material may be made of one metal selected from titanium, aluminum, and magnesium.

[0017] The first shielding gas can be an inert gas such as argon or nitrogen.

[0018] The second shielding gas can be an inert gas such as argon or nitrogen.

[0019] The gas guide plate can be positioned from the bottom of the anti-oxidation nozzle to the lower side in the height direction of the main nozzle.

[0020] A space is positioned between the inner surface of the gas guide plate and the outer surface of the main nozzle, and the width of the space may increase from the upper part to the lower part of the gas guide plate.

[0021] A slit may be provided in the injection section to inject the second shielding gas introduced into the injection section to the outside of the main nozzle.

[0022] Antioxidant nozzles can be applied in laser 3D printing processes or laser cladding processes. Effects of the invention

[0023] According to an embodiment of the present invention, since oxidation of the laminated portion can be continuously prevented even during solidification of the laminated portion after laser irradiation is completed, it can be applied to materials that have high reactivity with oxygen compared to iron.

[0024] In addition, when laminating a material that is highly reactive with oxygen compared to iron, the oxygen concentration in the laminated portion can be significantly reduced, and desired mechanical properties can be secured. Brief explanation of the drawing

[0025] FIG. 1 is a schematic cross-sectional view of an anti-oxidation device for a molten laminate according to one embodiment of the present invention. Specific details for implementing the invention

[0026] Hereinafter, embodiments of the present invention are described with reference to the attached drawings so that those skilled in the art can easily implement the present invention. As will be easily understood by those skilled in the art, the embodiments described below may be modified in various forms without departing from the concept and scope of the present invention. Where possible, identical or similar parts are indicated using the same reference numerals in the drawings.

[0027] The technical terms used below are for the reference of specific embodiments only and are not intended to limit the invention. The singular forms used herein include plural forms unless phrases clearly indicate otherwise. The meaning of "comprising" as used in the specification specifies a particular characteristic, area, integer, step, action, element, and / or component, and does not exclude the presence or addition of other particular characteristic, area, integer, step, action, element, component, and / or group.

[0028] All terms used below, including technical and scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms defined in advance are further interpreted to have meanings consistent with relevant technical literature and the present disclosure, and are not interpreted in an ideal or highly formal sense unless otherwise defined.

[0029] FIG. 1 is a schematic cross-sectional view of an anti-oxidation device for a molten laminate according to one embodiment of the present invention.

[0030] In this embodiment, an example is given where an anti-oxidation device for a molten laminate is applied to a metal 3D printing process.

[0031] Referring to FIG. 1, the anti-oxidation device for a molten laminate may include a main nozzle (10), an anti-oxidation nozzle (100), and a gas guide plate (200).

[0032] The main nozzle (10) may include a main passage (11) through which a laser beam (LB) and a first shielding gas (G1) pass, which is positioned in the center of the main nozzle (10) with respect to the width direction (X) centerline (Y1-Y1 line), and a powder passage (13) which is positioned outside the main passage (11) and supplies metal powder (Pw) to form a laminate (or laminate part (21), hereinafter referred to as a laminate part for convenience) on a material (20).

[0033] An anti-oxidation nozzle (100) is connected to and coupled to the upper part of the main nozzle (10), and can additionally spray a second shielding gas (G2) around the laminated part (21) so as to prevent oxidation of the laminated part (21) even during solidification of the laminated part (21) after the irradiation of the laser beam (LB) is completed.

[0034] A gas guide plate (200) may be installed at the lower part of the anti-oxidation nozzle (100) to guide the second shielding gas (G2) sprayed from the anti-oxidation nozzle (100) to the area around the stacking part (21).

[0035] The first shielding gas (G1) is a gas for forming a local inert atmosphere in the laminated portion (21) so as to prevent oxidation of the laminated portion (21), and may be composed of an inert gas such as argon (Ar) gas or nitrogen (N2) gas.

[0036] Additionally, the second shielding gas (G2) is a gas for forming an inert atmosphere around the laminated portion (21) to prevent oxidation around the laminated portion (21), and may be composed of an inert gas such as argon (Ar) gas or nitrogen (N2) gas.

[0037] Here, the term "periphery of the laminated portion (21)" refers to the upper part of the material (20) on the outer side of the laminated portion (21), and in particular, refers to the upper part of the material (20) corresponding to the gap (S1) between the gas guide plate (200) and the vertical line (L1-L1 line) on the outer side of the laminated portion (21).

[0038] In addition, the material (20) can be a material that is more reactive with oxygen than iron, and in particular, it can be made of one metal selected from titanium, aluminum, magnesium, etc.

[0039] The main nozzle (10) can be formed in a shape that becomes pointed from the top to the bottom to effectively irradiate the laminated portion (21) of the material (20) with a laser beam (LB).

[0040] The main passage (11) is positioned in the center of the main nozzle (10) based on the centerline (Y1-Y1 line) in the width direction (X) of the main nozzle (10), and a powder passage (13) may be positioned on the outside of the main passage (11).

[0041] The anti-oxidation nozzle (100) may include a nozzle body (110) and an inlet (120).

[0042] The nozzle body (110) is coupled to the outer surface of the upper part of the main nozzle (10) and may have a spraying part (111) for spraying a second shielding gas (G2).

[0043] Additionally, the inlet section (120) is positioned on the outer surface of the nozzle body (110) and is connected to the injection section (111) to allow the second shielding gas (G2) to be introduced into the injection section (111) at a set pressure.

[0044] The nozzle body (110) may be formed in a cylindrical shape having a hollow portion in the center to which the main nozzle (10) is coupled.

[0045] A shielding gas supply unit (not shown) for supplying a second shielding gas (G2) to the inlet (120) may be connected to the inlet (120).

[0046] A pressure regulating membrane (112) for regulating the pressure of the second shielding gas (G2) introduced into the injection section (111) may be installed in the injection section (111).

[0047] Additionally, a slit (113) may be disposed in the injection section (111) to spray the second shielding gas (G2) introduced into the injection section (111) to the outside of the main nozzle (10), by being disposed on the inner side of the upper part of the gas guide plate (200).

[0048] The slit (113) can be positioned parallel to the height direction (Y) of the main nozzle (10) so that the injection direction of the second shielding gas (G2) can be directed toward the lower height direction (Y) of the main nozzle (10).

[0049] The gas guide plate (200) can be positioned to have a length set from the lower end of the anti-oxidation nozzle (100) to the lower end of the main nozzle (10) in the height direction (Y) so as to easily guide the second shielding gas (G2) sprayed from the anti-oxidation nozzle (100) to the area around the stacking part (21).

[0050] That is, the space (201) between the inner surface of the gas guide plate (200) and the outer surface of the main nozzle (10) may have an inverted triangular structure that widens from the upper part of the gas guide plate (200) toward the lower part.

[0051] The space portion (201) may have an inverted right triangle structure that corresponds approximately to half of the right triangle of the main nozzle (10) based on the center line (Y1-Y1 line) in the width direction (X) of the main nozzle (10).

[0052] Since the space portion (201) widens from the upper portion to the lower portion of the gas guide plate (200), the second shielding gas (G2) induced by the gas guide plate (200) can be easily dispersed around the stacked portion (21).

[0053] Additionally, at least one dispersion plate (not shown) may be installed on the inner side of the gas guide plate (200) to evenly disperse the second shielding gas (G2), which is guided to the stacking part (21) by the gas guide plate (200), around the stacking part (21).

[0054] A plurality of dispersion plates are installed at set intervals on the inner surface of the gas guide plate (200) to reduce the pressure of the second shielding gas (G2) sprayed around the stacking part (21) to below the set pressure so as to prevent damage around the stacking part (21).

[0055] Hereinafter, with reference to FIG. 1, the operation of an anti-oxidation device for a molten laminate according to one embodiment of the present invention will be described.

[0056] First, when a laser beam (LB) is irradiated through the main passage (11) of the main nozzle (10), melting occurs at the moment the laser beam (LB) reaches the material (20), and a molten pool is created.

[0057] By spraying metal powder (Pw) into the molten pool through the powder passage (13), a laminated portion (21) is formed on the surface of the material (20).

[0058] At this time, the first shielding gas (G1) is sprayed through the central part of the main passage (11) to the upper part of the laminated section (21) as indicated by the solid arrow in Fig. 1, thereby forming a local inert atmosphere in the laminated section (21) and preventing oxidation of the laminated section (21).

[0059] In addition, a second shielding gas (G2) is injected into the space (201) between the gas guide plate (200) and the main nozzle (10) through the injection part (111) and slit (113) of the anti-oxidation nozzle (100).

[0060] In this way, the second shielding gas (G2) sprayed into the space (201) is guided to the periphery of the stacking section (21) by the gas guide plate (200) as shown by the dotted arrow in Fig. 1.

[0061] The second shielding gas (G2) guided to the periphery of the laminated portion (21) by the gas guide plate (200) forms an inert atmosphere around the laminated portion (21) to prevent oxidation around the laminated portion (21).

[0062] And, when the irradiation of the laser beam (LB) is completed, the supply of the laser beam (LB), the first shielding gas (G1), and the metal powder (Pw) is stopped.

[0063] Even when cooling for solidification of the laminated portion (21) of the material (20) after the main nozzle (10) moves following the completion of the laser beam (LB) irradiation, the second shielding gas (G2) through the spray portion (111) of the anti-oxidation nozzle (100) continues to be sprayed, thereby enabling continuous prevention of oxidation around the laminated portion (21).

[0064] Accordingly, the oxygen concentration around the laminated part (21) decreases even while cooling below the set temperature of the laminated part (21), so that oxidation occurring during cooling of the laminated part (21) can be prevented.

[0065] In addition, materials such as titanium, aluminum, and magnesium, which have high reactivity with oxygen compared to iron, can also be applied. Even when using materials with high reactivity with oxygen, the oxygen concentration in the laminated portion can be significantly reduced, and desired mechanical properties can be secured.

[0066] [Example]

[0067] Additive testing was performed using the DED metal 3D printing process with Ti64 powder.

[0068] The process conditions were set to a laser output of 700W, a powder feed rate of 3g / min, and a gas feed rate of 4L / min.

[0069] Comparative Example 1 is a case where lamination was performed using only the main nozzle (without an anti-oxidation nozzle).

[0070] Example 1 is a case where lamination is performed using both the main nozzle and the anti-oxidation nozzle according to an embodiment of the present invention (additional gas supply from the anti-oxidation nozzle: Ar gas 4L / min).

[0071] The oxygen concentration of the powder before lamination and the oxygen concentration of the laminated portion after lamination in Comparative Example 1 and Example 1 were analyzed (oxygen concentration of Ti64 powder: 815 ppm).

[0072] Comparative Example 1 has an oxygen concentration of 1304 ppm in the laminated section (an increase of 489 ppm compared to the powder concentration).

[0073] Example 1 has a laminated oxygen concentration of 1023 ppm (an increase of 208 ppm compared to the powder concentration).

[0074] When comparing the oxygen concentration of the laminated portions of Comparative Example 1 and Example 1, the oxygen concentration of Example 1 decreased by approximately 9% compared to Comparative Example 1.

[0075] In addition, when comparing the increase in oxygen concentration relative to powder concentration between Comparative Example 1 and Example 1, it was analyzed that the increase in oxygen concentration relative to powder concentration in Example 1 was reduced to 50% or less compared to Comparative Example 1.

[0076] As such, compared to Comparative Example 1 using only the main nozzle, it was analyzed that in the case of Example 1, in which an anti-oxidation nozzle was additionally applied in addition to the main nozzle, the oxygen concentration in the laminated section was reduced, and the oxygen concentration relative to the powder concentration was also reduced.

[0077] Although the anti-oxidation device for molten laminates according to one embodiment of the present invention has been described using a laser 3D printing process as an example, the present invention is not limited thereto and can also be applied to a laser cladding process.

[0078] Although the present disclosure has been described through preferred embodiments as described above, those skilled in the art will readily understand that the present invention is not limited thereto and that various modifications and variations are possible without departing from the scope of the claims set forth below. Explanation of the symbols

[0079] 10: Main nozzle 11: Main Passage 13: Powder passage 20: Material 21: Laminated part 100: Anti-oxidation nozzle 200: Gas induction plate

Claims

Claim 1 An oxidation prevention device for a molten laminate, comprising: a main nozzle having a main passage through which a laser beam and a first shielding gas pass, and a powder passage disposed outside the main passage to supply metal powder for forming a laminate of the material; and an anti-oxidation nozzle coupled to the upper end of the main nozzle and for additionally spraying a second shielding gas around the laminate even when the laminate is solidified after the irradiation of the laser beam is completed; a gas guide plate is installed at the lower end of the anti-oxidation nozzle to guide the second shielding gas around the laminate; a dispersion plate is installed on the inner surface of the gas guide plate to disperse the second shielding gas guided to the laminate by the gas guide plate around the laminate; and a plurality of dispersion plates are installed at set intervals on the inner surface of the gas guide plate to reduce the pressure of the second shielding gas sprayed around the laminate to a pressure below a set pressure. Claim 2 delete Claim 3 An oxidation prevention device for a molten laminate according to claim 1, wherein the oxidation prevention nozzle comprises a cylindrical nozzle body having a spray portion for spraying the second shielding gas coupled to the outer surface of the main nozzle, and an inlet portion disposed on the outer surface of the nozzle body for introducing the second shielding gas into the spray portion. Claim 4 An oxidation prevention device for a molten laminate, wherein, in paragraph 3, a pressure regulating membrane for regulating the pressure of the second shielding gas is installed in the injection part. Claim 5 In claim 1, the above material is an oxidation prevention device for a molten laminate made of one metal selected from titanium, aluminum, and magnesium. Claim 6 In claim 1, the first shielding gas is an inert gas such as argon gas or nitrogen gas, forming an oxidation prevention device for a molten laminate. Claim 7 In paragraph 6, the above second shielding gas is an oxidation prevention device for a molten laminate composed of an inert gas such as argon gas or nitrogen gas. Claim 8 In claim 1, the gas guide plate is an oxidation prevention device for a molten laminate positioned from the lower end of the oxidation prevention nozzle to the lower end in the height direction of the main nozzle. Claim 9 An oxidation prevention device for a molten laminate according to claim 1, wherein a space is disposed between the inner surface of the gas guide plate and the outer surface of the main nozzle, and the space widens from the upper part to the lower part of the gas guide plate. Claim 10 An oxidation prevention device for a molten laminate according to paragraph 3, wherein the injection part has a slit arranged therein for injecting the second shielding gas introduced into the injection part to the outside of the main nozzle. Claim 11 delete

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