3D printing equipment

Abstract

The 3D printing apparatus includes a stage that provides a support base for the object; first and second discharge nozzles arranged on the stage to respectively discharge a first material in a paste or slurry state that forms the outline of the object and a second material in a liquid state that fills a filling space surrounded by the outline of the object made of the first material; an extrusion device connected to the first discharge nozzle that extrudes the first material toward the first discharge nozzle to discharge the first material in a paste or slurry state that is a mixture of ceramic particles and a matrix in which the ceramic particles are dispersed; a heating funnel connected to the second discharge nozzle that uses a metal block as an input and melts the metal block to discharge the second material in a liquid metal flow state formed by melting the metal block through the second discharge nozzle; and a heating chamber that houses the stage and provides a space for slowly cooling the first and second materials accumulated on the stage from the first and second discharge nozzles.

Description

[Technical Field]

[0001] The present invention relates to a 3D printing device. [Background technology]

[0002] A 3D printing device is a device used to form a model having a specific shape, and may produce the model by, for example, inputting sliced ​​section data of the model to be produced and stacking each layer of the model. For example, such a 3D printing device may generate the three-dimensional shape of the model to be produced as digital data through computer modeling, differentiate it into a two-dimensional plane, and then continuously stack the differentiated material to produce the model having a three-dimensional shape. Summary of the Invention [Problem to be solved by the invention]

[0003] One embodiment of the present invention includes a 3D printing device that can reduce the time required to produce a model. One embodiment of the present invention includes a 3D printing device having a structure for fabricating a built object. An embodiment of the present invention includes a 3D printing apparatus that can form a molded object with a smooth surface and beautiful appearance while reducing internal defects such as voids and thermal stress. [Means for solving the problem]

[0004] In order to solve the above problems and other problems, the 3D printing apparatus of the present invention is a stage that provides a support base for the object to be modeled; first and second discharge nozzles arranged on the stage so as to respectively discharge a first material in a paste or slurry state that forms the outline of the object, and a second material in a liquid phase that fills a filling space surrounded by the outline of the object made of the first material; an extrusion device connected to the first discharge nozzle for extruding a first material toward the first discharge nozzle so as to discharge a first material in a paste or slurry state in which ceramic particles and a matrix in which the ceramic particles are dispersed are mixed; a heating funnel connected to the second discharge nozzle, the heating funnel receiving the metal block as an input and melting the metal block so as to discharge a second material in the form of a molten liquid metal flow through the second discharge nozzle; a heating chamber for accommodating the stage and providing a space for slowly cooling the first and second materials accumulated on the stage from the first and second discharge nozzles. [Effects of the Invention]

[0005] According to the present invention, there is provided a 3D printing device that has a structure for producing a molded object, shortens the time required to produce the object, and can produce a molded object with a smooth surface, beautiful appearance, and reduced internal defects such as voids and thermal stress. [Brief explanation of the drawings]

[0006] [Figure 1] 1 shows a general perspective view of a 3D printing apparatus according to one embodiment of the present invention. [Figure 2] FIG. 2 is a diagram for explaining the formation of an object to be formed by the 3D printing device shown in FIG. 1, and shows a plan view illustrating a partial configuration of FIG. 1. [Figure 3] 3 is a cross-sectional view taken along line III-III' in FIG. 2, illustrating the formation of a 3D object to be formed by the 3D printing apparatus shown in FIG. 1. [Figure 4] This is a diagram for explaining the formation of a molded object to be formed by the 3D printing device shown in Figure 1, and illustrates the contour of the molded object formed from first and second discharge positions on a stage where different first and second materials are discharged, and the formation of the molded object filling the filling space surrounded by the contour of the molded object. [Figure 5] 1. FIG. 2 is a diagram illustrating the general configuration of the extrusion device shown in FIG. 1 for explaining the extrusion device shown in FIG. [Figure 6] The drawings are for explaining the contour of the object formed from the first and second discharge positions on the stage where the first and second materials are discharged, and the molding of the object that fills the filled space surrounded by the contour of the object, and are for explaining a drive mode in which the discharge of the first and second materials is performed in a temporal order, and a drive mode in which the discharge of the first and second materials is performed simultaneously. [Figure 7] The drawings are for explaining the contour of the object formed from the first and second discharge positions on the stage where the first and second materials are discharged, and the molding of the object that fills the filled space surrounded by the contour of the object, and are for explaining a drive mode in which the discharge of the first and second materials is performed in a temporal order, and a drive mode in which the discharge of the first and second materials is performed simultaneously. [Figure 8] A perspective view of a portion of the 3D printing apparatus shown in FIG. 1 is shown. [Figure 9] FIG. 9 is an exploded perspective view illustrating the assembly between the heating funnel, the discharge unit, and the first heat source embedded in the embedding block shown in FIG. 8. [Figure 10] An exploded perspective view is shown to illustrate the airtight assembly between the embedding block and the heating chamber. [Figure 11] 11 is an exploded perspective view illustrating the discharge holes formed in the embedded block shown in FIG. [Figure 12] A drawing is shown to explain a configuration in which the flow rate (volume passing through the cross-sectional area per unit time) or discharge speed of the second material in the heating funnel is controlled by a sealing cover placed on the heating funnel and the internal pressure of the gas filled in the sealing cover. [Figure 13](a) A diagram showing an example of the temperature profile of the first temperature T1 in the heating funnel 10 and the temperature profile of the second temperature T2 in the discharge unit 20, which are followed as the target temperature during the takt time for producing one molded product. (b) A diagram showing an example of the temperature profile of the third temperature T3 in the heating chamber 50, which is followed as the target temperature during the takt time for producing one molded product, and showing an example of a slow profile of the third temperature T3 for slow cooling of the molded product. [Figure 14] 10A and 10B are diagrams for explaining the change in the amount of movement of the stage S required to move to the same target position depending on the distance g between the first and second discharge nozzles 20a and 10a, which are different from each other. [Figure 15] Different drawings are shown to explain the power connection between the stage S, which provides the support base for the object shown in Figure 1, and the actuator A, as well as the bellows cover ZC and link structure L connected to the bellows cover ZC for sealing the opening 50'''' of the heating chamber 50 regardless of the operation of the actuator A. [Figure 16] Different drawings are shown to explain the power connection between the stage S, which provides the support base for the object shown in Figure 1, and the actuator A, as well as the bellows cover ZC and link structure L connected to the bellows cover ZC for sealing the opening 50'''' of the heating chamber 50 regardless of the operation of the actuator A. DETAILED DESCRIPTION OF THE INVENTION

[0007] The 3D printing device of the present invention is a stage that provides a support base for the object to be modeled; a first discharge nozzle and a second discharge nozzle arranged on the stage so as to respectively discharge a first material in a paste or slurry state that forms the outline of the object, and a second material in a liquid phase that fills a filling space surrounded by the outline of the object made of the first material; an extrusion device connected to the first discharge nozzle for extruding a first material toward the first discharge nozzle so as to discharge a first material in a paste or slurry state in which ceramic particles and a matrix in which the ceramic particles are dispersed are mixed; a heating funnel connected to the second discharge nozzle, the heating funnel receiving the metal block as an input and melting the metal block so as to discharge a second material in the form of a molten liquid metal flow through the second discharge nozzle; a heating chamber for accommodating the stage and providing a space for slowly cooling the first and second materials accumulated on the stage from the first and second discharge nozzles.

[0008] For example, the inner diameter of the second discharge nozzle may be smaller than the diameter corresponding to the longest dimension of the metal block to be inserted through the upper inlet of the heating funnel connected to the lower second discharge nozzle.

[0009] For example, the inner diameter of the disk-shaped metal block is 50 mm, which is the diameter of the disk. The inner diameter of the second discharge nozzle is set to 0.1 mm to 4 mm, for example, 1 mm to 2 mm.

[0010] For example, the heating funnel may be formed in a Y-shape such that the inner diameter gradually decreases from the inner diameter of the upper inlet through which the metal block is introduced to the inner diameter of the second discharge nozzle at the lower end through which the second material of the metal flow is discharged.

[0011] For example, a first heat source for melting a metal block placed in the heating funnel is wound around the outer circumferential surface of the heating funnel.

[0012] For example, the first heat source may be disposed between a heating funnel having a second discharge nozzle formed at a lower end facing the stage and a discharge unit having a first discharge nozzle formed at a lower end facing the stage.

[0013] For example, the 3D printing device may further include an embedding block for embedding both the first and second discharge nozzles.

[0014] For example, the embedding block embeds and fixes the first and second discharge nozzles in position so that the distance between the first and second discharge nozzles is maintained at 3 mm to 50 mm, and for example, the embedding block may maintain the distance between the first and second discharge nozzles at approximately 25 mm.

[0015] For example, the embedded block is formed to a height from the lower end of the heating funnel and the discharge unit, on which the first and second discharge nozzles are formed, to a height that exposes the inlet at the upper end of the heating funnel and the fitting end at the upper end of the discharge unit, A connecting pipe for transferring the first material between the extrusion device and the upper fitting end of the discharge unit may be sandwiched.

[0016] For example, the embedded block may surround a first heat source wound on the outer peripheral surface of the heating funnel while being spaced apart from the first heat source wound on the outer peripheral surface of the heating funnel and together surrounding an ejection unit extending parallel to the outer peripheral surface of the heating funnel.

[0017] For example, the discharge unit may include a second discharge nozzle extending from a bend in the discharge unit toward the stage parallel to the first discharge nozzle, extending along a diagonal direction that simultaneously follows the height and radial directions of the heating funnel so as to be parallel to the outer surface of the heating funnel, and extending parallel to the first discharge nozzle that extends from a bottleneck that forms the smallest inner diameter of the heating funnel toward the stage.

[0018] For example, the second temperature of the heating funnel and the first temperature of the discharge unit may satisfy the relationship: second temperature > first temperature.

[0019] For example, the temperature deviation between the first and second temperatures can be induced by a thermal resistance made of the insulating material of the embedding block filling between the heating funnel and the discharge unit, which run parallel to each other.

[0020] For example, the second temperature of the heating funnel is set to a temperature sufficiently higher than the melting point of the metal block, The first temperature of the discharge unit can be set to a temperature that is sufficiently low to suppress evaporation or volatilization of the matrix mixed in the first material.

[0021] For example, the third temperature of the slow cooling space of the heating chamber may satisfy the relationship of second temperature>third temperature>first temperature in relation to the second temperature of the heating funnel and the first temperature of the discharge unit.

[0022] For example, the third temperature of the annealing space of the heating chamber may be set to a temperature high enough to induce vaporization or volatilization of the matrix mixed with the first material in the annealing space.

[0023] For example, the embedding block and the heating chamber may be connected vertically via a discharge hole that allows the first and second materials to flow from first and second discharge nozzles embedded in the embedding block toward a stage accommodated in the annealing space of the heating chamber.

[0024] For example, the embedding block may be an upper block embedding the discharge units and heating funnels, each including a first and second discharge unit at its lower end; The cooling chamber may include a lower block formed on a plate having an area expanded from the upper block and covering an upper portion of the annealing space.

[0025] For example, the heating chamber may include a number of partition walls that abut on the lower block via stepped interfaces and cover the sides of the annealing space.

[0026] For example, adjacent partitions forming corners of the heating chamber may abut against each other via a stepped interface.

[0027] For example, the heating chamber may further include a bottom wall having an opening formed therein for a connecting rod to pass through, the connecting rod mediating a power connection between a stage inside the annealing space and an actuator outside the annealing space by providing an assembly position on which the plurality of partitions are placed, The 3D printing device may further include a bellows cover extending parallel to the connecting rod and superimposed on the bottom wall to cover the opening via a link structure that expands and contracts as the actuator rises and falls.

[0028] For example, the 3D printing device a first heat source wound around the outer circumferential surface of the heating funnel for melting a metal block inserted into the heating funnel; The apparatus may further include a second heat source formed within the heating chamber for controlling a cooling rate of the first and second materials discharged from the first and second discharge nozzles and accumulated on the stage.

[0029] For example, during the takt time to create one object, A first operating time from the start of operation of the first heat source to the end of operation and a second operating time from the start of operation of the second heat source to the end of operation may have a length relationship of first operating time<second operating time.

[0030] For example, during the takt time to create one object, The second heat source may be operable to control the cooling rate of the object even after the operation of the first heat source has been stopped.

[0031] For example, the 3D printing device does not include a sintering device for solidifying the object to complete a solid-phase object.

[0032] For example, the first and second discharge nozzles may be moved together, so that the discharge positions of the first and second materials may be formed simultaneously on the stage.

[0033] For example, the flow rate of the first material discharged onto the stage from the first discharge nozzle is smaller than the flow rate of the second material discharged onto the stage from the second discharge nozzle.

[0034] For example, the volume of the contour of the object formed from the first material is smaller than the volume of the object itself formed from the second material.

[0035] For example, the extrusion device may include first and second hoppers into which ceramic particles and a matrix are respectively introduced, a transfer pipe connected to the first and second hoppers, and a rotary screw that is rotated within the transfer pipe to mix the ceramic particles and the matrix introduced from the first and second hoppers to form a first material and to forcibly transfer the first material along the direction of the transfer pipe.

[0036] For example, the flow rate of the first material discharged onto the stage from the first discharge nozzle can be controlled by the rotation speed of a rotary screw driven inside the transfer pipe.

[0037] For example, the flow rate of the second material discharged onto the stage from the second discharge nozzle can be controlled by the pressure of the gas filled above the liquid surface of the metal flowing second material inside the heating funnel, for example, by the pressure of the rare gas.

[0038] In one embodiment of the present invention, the 3D printing device comprises: a stage that provides a support base for the object to be modeled; the first and second discharge nozzles on the stage include a first discharge nozzle that discharges a first material in a paste state or a slurry state that forms the outline of the object to be modeled, and a second discharge nozzle that discharges a second material in a liquid state that fills a filling space surrounded by the first material; an extrusion device connected to the first discharge nozzle, extruding a first material in a paste or slurry state toward the first discharge nozzle to extrude a first material including ceramic particles and a matrix in which the ceramic particles are dispersed; a heating funnel connected to the second discharge nozzle, the heating funnel receiving the metal block, melting the metal block, and supplying a second material in a liquid state; and a heating chamber for accommodating the stage, the heating chamber providing a space for slow cooling of the object formed by the first and second materials accumulated on the stage.

[0039] A 3D printing method according to one embodiment of the present invention includes: extruding a first material including ceramic particles and a matrix in which the ceramic particles are dispersed as a first material in a paste or slurry state from an extrusion device toward a first discharge nozzle; discharging a first material through a first discharge nozzle to form an outline of a target object; receiving a metal block through a heating funnel; melting the metal block to form a molten metal block stream and directing the molten metal second material toward a second discharge nozzle; discharging a second material through a second discharge nozzle so that the second material fills a filling space surrounding the contour of the object formed from the first material; and forming a model on the stage by repeatedly discharging the first and second materials layer by layer.

[0040] Hereinafter, a 3D printing apparatus according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

[0041] In one embodiment of the present invention, the 3D printing device forms the object to be printed using the same material or two or more materials, and in this case, the two or more materials may have the same phase (solid phase, liquid phase, solid-liquid mixed phase) or different phases.

[0042] In one embodiment of the present invention, the 3D printing device uses a multi-phase material, where a multi-phase material refers to at least two or more different materials (first and second materials) having two different phases. In one embodiment of the present invention, two different phases collectively refer to a solid phase, a liquid phase, a gas phase, a molten phase, a mixed phase (solid-liquid mixed phase), etc., and the at least two materials are used in different ratios or individually. In one embodiment of the present invention, a target object to be printed may be stacked layer by layer on a stage of the 3D printing device.

[0043] FIG. 1 shows a general perspective view of a 3D printing apparatus according to one embodiment of the present invention. FIG. 2 is a diagram for explaining the formation of an object to be formed by the 3D printing device shown in FIG. 1, and shows a plan view illustrating a portion of the configuration of FIG. FIG. 3 is a cross-sectional view taken along line III-III' in FIG. 2, illustrating the formation of an object to be formed by the 3D printing device shown in FIG. 1. Figure 4 is a diagram for explaining the formation of a molded object to be formed by the 3D printing device shown in Figure 1, and shows the outline of the molded object formed from the first and second ejection positions P1 and P2 on the stage S where the different first and second materials M1 and M2 are ejected, and the molding of the molded object that fills the filling space FS surrounded by the outline of the molded object. FIG. 5 is a diagram illustrating the extrusion device 80 shown in FIG. 1, showing a schematic configuration of the extrusion device 80 shown in FIG. Figures 6 and 7 are drawings for explaining the contour of the object formed from the first and second ejection positions P1 and P2 on the stage S where the first and second materials M1 and M2 are ejected, and the molding of the object that fills the filling space FS surrounded by the contour of the object.The drawings are for explaining a drive mode in which the ejection of the first and second materials M1 and M2 is performed in a temporal order, and a drive mode in which the ejection of the first and second materials M1 and M2 is performed simultaneously. FIG. 8 shows a perspective view of a portion of the 3D printing apparatus shown in FIG. FIG. 9 is an exploded perspective view illustrating the assembly between the heating funnel 10, the discharge unit 20, and the first heat source 15 embedded in the embedding block 40 shown in FIG. FIG. 10 shows an exploded perspective view illustrating the airtight assembly of the embedding block 40 and the heating chamber 50. As shown in FIG. FIG. 11 is an exploded perspective view illustrating the discharge holes 40'' formed in the embedding block 40 shown in FIG. Figure 12 shows a diagram to explain a configuration in which the flow rate (volume passing through the cross-sectional area per unit time) or discharge speed of the second material M2 in the heating funnel 10 is controlled by the sealing cover 1 placed on the heating funnel 10 and the internal pressure of the gas RG filled in the sealing cover 1. Figure 13(a) shows an example diagram illustrating the temperature profile of the first temperature T1 in the heating funnel 10 and the temperature profile of the second temperature T2 of the discharge unit 20, which are followed as target temperatures during the takt time for producing one molded product. Figure 13(b) shows an example of the temperature profile of the third temperature T3 in the heating chamber 50 that is followed as the target temperature during the takt time for producing one molded object, and shows an example of a slow profile of the third temperature T3 for slow cooling of the molded object. Figures 14(a) and (b) show diagrams for schematically explaining the change in the amount of movement of the stage S required to move to the same target position depending on the spacing g between the first and second discharge nozzles 20a, 10a, which are different from each other. Figures 15 and 16 show different views to explain the power connection between the stage S, which provides the support base for the object shown in Figure 1, and the actuator A, as well as the bellows cover ZC and link structure L connected to the bellows cover ZC for sealing the opening 50'''' of the heating chamber 50 regardless of the operation of the actuator A.

[0044] Referring to the drawings, a 3D printing apparatus according to an embodiment of the present invention includes a stage S that provides a support base for a target object to be formed, first and second discharge nozzles 20a, 10a disposed on the stage S to respectively discharge a first material M1 in a paste or slurry state that forms the outline of the target object, and a second material M2 in a liquid phase that fills a filling space FS surrounded by the outline of the target object formed in the first material M1, and the first discharge nozzle 20a is connected to the second discharge nozzle 20a, and the first material M1 is in a paste or slurry state that is a mixture of ceramic particles and a matrix in which the ceramic particles are dispersed. The extrusion device 80 may include an extrusion device 80 for extruding the first material M1 toward the first discharge nozzle 20a to discharge the first material M1 in a lie state, a heating funnel 10 connected to the second discharge nozzle 10a, which receives the metal block as an input and melts the metal block so as to discharge the second material M2 in a liquid phase metal flow state through the second discharge nozzle 10a, and a heating chamber 50 for accommodating the stage S and providing a slow cooling space 50' for the first and second materials M1 and M2 accumulated on the stage S from the first and second discharge nozzles 20a, 10a.

[0045] A 3D printing device according to one embodiment of the present invention can form a three-dimensional object by accumulating first and second materials M1 and M2 supplied from first and second discharge nozzles 20a and 10a according to sliced ​​section data of the three-dimensional object to be formed.

[0046] In one embodiment of the present invention, the first material M1 for forming the contour of the object to be formed may be formed in a paste or slurry state by mixing ceramic particles with a matrix in which the ceramic particles are dispersed. More specifically, the first material M1 may be formed in a paste or slurry state by mixing ceramic particles with a matrix that provides fluidity for the ceramic particles. In one embodiment of the present invention, the matrix may be a base material that contains the ceramic particles in a dispersed state so as to form the first material M1 in a paste or slurry state in which the ceramic particles are dispersed. The matrix may have a fluid material phase, such as a liquid or gel phase, and may include water (H2O) to provide fluidity for the ceramic particles. In one embodiment of the present invention, the matrix includes water (H2O) as a vehicle that provides fluidity for the ceramic particles, but does not include any other additives, such as a binder for controlling the viscosity of the first material M1. In a specific embodiment of the present invention, the first material M1 may include a plurality of ceramic particles and water (H2O) as a matrix in which the ceramic particles are dispersed. Meanwhile, the second material M2 for forming the object itself within the contour of the object may be made of a liquid metal, more specifically, a liquid metal flow.

[0047] In one embodiment of the present invention, the first and second materials M1 and M2 are prepared from different first and second raw materials through different pre-treatment processes. For example, the first material M1 in a paste or slurry state and the second material M2 in a liquid phase are different material phases having different fluidities, and therefore the first and second materials M1 and M2 may be supplied onto the stage S through different pre-treatment processes.

[0048] The first material M1 may be a composite material in a paste or slurry state in which solid ceramic particles and a liquid (or gel) vehicle and / or binder are mixed, for example, the ceramic particles may have a particle size on the micrometer scale. The first material M1 may be formed in a paste or slurry state in which the ceramic particles are dispersed, but has less fluidity than the second material M2, which is a liquid metal or metal fluid. The first material M1 may be forcibly transported through the first discharge nozzle 20a or the connecting pipe 70 connected to the first discharge nozzle 20a by extrusion to form a homogeneous mixture (or a homogeneous dispersion) between the ceramic particles (solid phase) and the matrix (liquid or gel phase) containing the ceramic particles, which have different material phases.

[0049] For example, the extrusion device 80 for extruding the first material M1 includes a first hopper 81 into which ceramic particles forming a solid phase component of the first material M1 are introduced, and a second hopper 82 into which a matrix containing the ceramic particles to form a paste or slurry state is introduced. The ceramic particles and the matrix introduced from the first and second hoppers 81 and 82 are introduced together into a transfer pipe 83 of the extrusion device 80, and are mixed with each other through a rotary screw 85 formed inside the transfer pipe 83. The mixed ceramic particles and the matrix are then transferred along a supply direction toward the stage S. For example, the first material M1 may be transferred between the discharge port 80a of the extrusion device 80 and a first discharge nozzle 20a or a discharge unit 20 including a lower first discharge nozzle 20a formed on the stage S via a connecting pipe 70 that mediates the transfer of the first material M1. The mixed ceramic particles and the matrix may then be discharged onto the stage S through the first discharge nozzle 20a at the lower end of the discharge unit 20, along the discharge unit 20 embedded in the embedding block 40 (described later). For example, in one embodiment of the present invention, the upstream end of the connecting pipe body 70 may be connected to the discharge port 80a of the extrusion device 80, and the downstream end of the connecting pipe body 70 may be connected to the discharge unit 20 including a first discharge nozzle 20a at the lower end.

[0050] Although not shown in the drawings, the term "extrusion device 80" used throughout this specification is not limited to the above-described rotary screw 85-based configuration, but may be broadly interpreted, and may also refer to, for example, a piston-based extrusion device in which pre-processed ceramic paste contained in a piston container is pressurized toward the discharge unit 20 by piston drive.

[0051] The second material M2 is composed of a liquid metal or metal flow formed from a heating funnel 10 that takes a solid metal block as input and heats the input metal block above its melting point, and the molten metal or metal flow in the internal space of the heating funnel 10 can be ejected onto the stage S through a second ejection nozzle 10a that forms the lower end of the heating funnel 10.

[0052] That is, in one embodiment of the present invention, a metal block serving as the second raw material M2 (second raw material) is introduced into a heating funnel 10 including a second discharge nozzle 10a at the lower end through which the second raw material M2 is discharged, and the heating funnel 10 is heated to a temperature above the melting point of the metal block, thereby forming a liquid metal flow that forms the second raw material M2. For example, in one embodiment of the present invention, the low-melting-point metal block serving as the second raw material M2 (second raw material) is a slim, disk-shaped block with a low height, and the longest dimension of the low-melting-point metal block corresponds to the diameter of the disk, which is approximately 50 mm in diameter. In another embodiment of the present invention, the heating funnel 10, which receives the low-melting-point metal block as an input and discharges the metal flow, is substantially Y-shaped, and the inner diameter of the second discharge nozzle 10a at the lower end through which the metal flow is discharged is smaller than the inner diameter of the inlet at the upper end through which the low-melting-point metal block is introduced. For example, the inner diameter of the upper inlet through which the low-melting-point metal block is introduced is larger than the longest dimension of the low-melting-point metal block, whereas the inner diameter of the lower second discharge nozzle 10a through which the metal flow formed by melting the low-melting-point metal block in the heating funnel 10 is introduced is smaller than the longest dimension of the low-melting-point metal block. More specifically, when the longest dimension of the low-melting-point metal block corresponds to the diameter of the disk-shaped low-melting-point metal block and the diameter of the disk is approximately 50 mm, in one embodiment of the present invention, the inner diameter of the second discharge nozzle 10a is approximately 0.1 mm to 4 mm, which is smaller than the diameter of the solid disk (50 mm), and may be, for example, approximately 1 mm to 2 mm.

[0053] In this specification, the vertical direction Z1 or height direction Z1 corresponds to the direction in which the first and second materials M1 and M2 are ejected from the first and second ejection nozzles 20a and 10a onto the stage S, and refers to the direction in which the first and second ejection nozzles 20a and 10a ejecting the first and second materials M1 and M2 are spaced apart from the stage S. For example, the lower and upper ends of the heating funnel 10 refer to the close-distance end relatively adjacent to the stage S and the far-distance end relatively far from the stage S at both ends of the heating funnel 10 along the height direction Z1. Similarly, the lower and upper ends of the ejection unit 20 may refer to the close-distance end relatively adjacent to the stage S and the far-distance end relatively far from the stage S at both ends of the ejection unit 20.

[0054] In one embodiment of the present invention, the heating funnel 10 may correspond to a configuration for discharging a first material M1 onto a stage S through a first discharge nozzle 20a formed at a lower end thereof, and the discharge unit 20 may correspond to a configuration for discharging a second material M2 onto the stage S through a second discharge nozzle 10a formed at a lower end thereof. As will be described later, the heating funnel 10 and the discharge unit 20 are embedded together in an embedding block 40, and the embedding block 40 embeds and fixes the heating funnel 10 and the discharge unit 20 together, thereby defining a distance g between the first discharge nozzle 20a forming the lower end of the heating funnel 10 and the second discharge nozzle 10a forming the lower end of the discharge unit 20. In one embodiment of the present invention, the embedded block 40 surrounds the first heat source 15 wound around the outer surface of the heating funnel 10, insulating the internal space of the heating funnel 10 from the surrounding environment so that the temperature of the internal space of the heating funnel 10 controlled by the first heat source 15 is maintained at a second temperature T2 above the melting point of the metal block, and can maintain the temperature of the discharge unit 20 located on the opposite side of the heating funnel 10 across the first heat source 15 at a first temperature T1 that is higher than the temperature of the surrounding environment or room temperature but lower than the melting point of the metal block. In one embodiment of the present invention, the embedding block 40 is made of a heat insulating material and is interposed between the heating funnel 10 and the discharge unit 20 for discharging the first and second materials M1 and M2, respectively, to generate thermal resistance between them and induce a temperature difference. For example, the second temperature T2 of the internal space of each heating funnel 10 can be formed to be higher than the melting point of the metal block, while the first temperature T1 of the discharge unit 20 can be maintained lower than the melting point of the metal block but higher than the temperature of the surrounding environment or room temperature.

[0055] In one embodiment of the present invention, the heating funnel 10 has an approximately Y-shaped funnel shape in which the inner diameter gradually narrows from the inner diameter of the upper inlet to the inner diameter of the second discharge nozzle 10a at the lower end, and in this case, the discharge unit 20 extends in an oblique direction inclined to extend parallel to the heating funnel 10, and the heating funnel 10 and the discharge unit 20 extending parallel to each other can maintain a determined distance along the height direction Z1 from the upper end to the lower second discharge nozzle 10a and first discharge nozzle 20a. For example, in one embodiment of the present invention, the heating funnel 10 may extend in a funnel shape along the height direction Z1, with the inner diameter gradually narrowing in the radial directions Z2 and Z3, forming a second discharge nozzle 10a at its lower end extending linearly along the height direction Z1 toward the stage S. The discharge unit 20 extending parallel to the heating funnel 10 may extend diagonally to simultaneously follow the height direction Z1 and the radial directions Z2 and Z3, forming a first discharge nozzle 20a extending linearly along the height direction Z1 toward the stage S. In one embodiment of the present invention, the heating funnel 10 and the discharge unit 20 may form deformation points at the positions of the second discharge nozzle 10a and the first discharge nozzle 20a, respectively, thereby forming a bottleneck with the smallest inner diameter of the heating funnel 10 or a bend in the discharge unit 20. In one embodiment of the present invention, the bottleneck of the heating funnel and the bend in the discharge unit may be formed at the same level along the height direction.

[0056] In one embodiment of the present invention, the heating funnel 10 and the discharge unit 20 extend parallel to each other at the same level and at the same interval along the height direction Z1, and the heating funnel 10 and the discharge unit 20 may extend from the upper end to the lower end second discharge nozzle 10a and the lower end first discharge nozzle 20a while maintaining the same interval g between the second discharge nozzle 10a and the first discharge nozzle 20a that form their respective lower ends.

[0057] In one embodiment of the present invention, the temperatures of the heating funnel 10 and the discharge unit 20 are maintained at different first and second temperatures T1 and T2 through a first heat source 15 interposed between the heating funnel 10 and the discharge unit 20 and an embedded block 40 filling the gap between the heating funnel 10 and the discharge unit 20. For example, the heating funnel 10 and the discharge unit 20 can be maintained at different second and first temperatures T2 and T1 by forming thermal resistance through the insulating material of the embedded block 40 filling the gap between the heating funnel 10 and the discharge unit 20.

[0058] The first temperature T1 may be lower than the melting point of the metal block and higher than the temperature of the surrounding environment or room temperature, and the second temperature T2 may be higher than the melting point of the metal block. In one embodiment of the present invention, the first temperature T1 of the discharging unit 20 may be low enough to maintain the first material M1 in a paste or slurry state while suppressing evaporation or volatilization of a matrix containing dispersed ceramic particles from the first material M1 discharged from the first discharging nozzle 20a forming the lower end of the discharging unit 20, and may be high enough to maintain gradual cooling of the second material M2 from contact between the first and second materials M1 and M2 so as to suppress rapid cooling of the second material M2 in a liquid phase that forms the object itself while contacting the first material M1 that forms the outline of the object on the stage S and the resulting quenching heat treatment effect, i.e., to induce an annealing heat treatment effect on the second material M2 that contacts the first material M1 that forms the outline of the object on the stage S. Meanwhile, the second temperature T2 of the heating funnel 10 or the second temperature T2 of the internal space of the heating funnel 10 may correspond to a temperature higher than the melting point of the metal block, and the second temperature T2 of the internal space of the heating funnel 10 may correspond to a temperature higher than the melting point of the metal block so that the metal block introduced into the internal space of the heating funnel 10 is melted and the liquid second material M2 is discharged through the second discharge nozzle 10a that forms the lower end of the heating funnel 10. For example, in one embodiment of the present invention, the first heat source 15 is wound around the outer surface of the heating funnel 10, maintaining the temperature of the internal space of the heating funnel 10 at a second temperature T2 above the melting point of the metal block, insulating the internal space of the heating funnel 10 from the surrounding environment through the embedded block 40 surrounding the first heat source 15 wound around the outer surface of the heating funnel 10, and forming a thermal resistance that can induce a temperature difference between the second temperature T2 of the internal space of the heating funnel 10 and the first temperature T1 of the discharge unit 20 through the insulating material of the embedded block 40 that fills the gap between the outer surface of the heating funnel 10 around which the first heat source 15 is wound and the discharge unit 20.For example, in one embodiment of the present invention, the first temperature T1 is lower than the melting point of the metal block and higher than the temperature of the surrounding environment or room temperature, and the second temperature T2 is higher than the melting point of the metal block, thereby satisfying the relationship of first temperature T1 of the discharge unit 20 < second temperature (T2 or second temperature T2 of the internal space of the heating funnel 10) of the heating funnel 10. The first heat source 15 responsible for the first temperature T1 of the discharge unit 20 and the second temperature T2 of the heating funnel 10 is interposed between the discharge unit 20 and the heating funnel 10, which extend parallel to each other, but is positioned further adjacent to the heating funnel 10 side so as to form a relatively high second temperature T2. For example, the first heat source 15 may be wound around the outer peripheral surface of the heating funnel 10, and the discharge unit 20 may be positioned with an insulating material of an embedded block 40 interposed between it and the first heat source 15 wound around the outer peripheral surface of the heating funnel 10.

[0059] In this specification, the expression "embedding both the heating funnel 10 and the discharge unit 20 in the embedding block 40" does not mean that the embedding block 40 completely embeds both the heating funnel 10 and the discharge unit 20, but rather that the first and second discharge nozzles 20a, 10a forming the lower ends of the heating funnel 10 and the discharge unit 20 are completely embedded, but the input port forming the upper end of the heating funnel 10 is exposed so that the position of the input port through which the metal block is input can be externally confirmed, and the upper end of the discharge unit 20 into which the connecting pipe 70 connected to the extrusion device 80 is sandwiched is exposed. For example, in relation to the position of the heating funnel 10 embedded in the embedding block 40, the embedding block 40 may almost embed the heating funnel 10 with the first heat source 15 wound around it, but may expose the upper part of the heating funnel 10 from the input port forming the upper end of the heating funnel 10 to a level prior to the start of winding the first heat source 15. In one embodiment of the present invention, the embedding block 40 provides insulation from the surrounding environment to prevent heat loss from the first heat source 15 wound around the outer circumferential surface of the heating funnel 10. Therefore, in one embodiment of the present invention, the embedding block 40 embeds the heating funnel 10 at least from the start of winding the first heat source 15 to the end of winding, and may expose, for example, the portion of the heating funnel 10 from an inlet formed at the top end of the heating funnel 10 up to the start of winding the first heat source 15.

[0060] In one embodiment of the present invention, the embedding block 40 embeds most of the heating funnel 10 and the discharge unit 20, but exposes the inlet forming the upper end of the heating funnel 10 and the fitting end 20b forming the upper end of the discharge unit 20, and may expose the upper parts of the heating funnel 10 and the discharge unit 20 with a predetermined clearance, including the upper end of the heating funnel 10 for inserting the metal block and the upper end of the discharge unit 20 for connecting the connecting pipe 70. Meanwhile, in one embodiment of the present invention, in addition to the inlet forming the upper end of the heating funnel 10 and the fitting end 20b forming the upper end of the discharge unit 20, the upper part of the embedding block 40 exposes the electrical contacts 15a of the first heat source 15 surrounding the outer periphery of the heating funnel 10, and the electrical contacts 15a of the first heat source 15 protrude to the highest level to block electrical interference with other surrounding components, for example, may protrude to a level higher than the inlet of the heating funnel 10 and the fitting end 20b of the discharge unit 20 in the height direction Z1.

[0061] In one embodiment of the present invention, the embedding block 40 embeds the heating funnel 10 and the discharge unit 20 together with the first heat source 15. The embedding block 40 embedding the heating funnel 10 and the discharge unit 20 together may be connected to a heating chamber 50 that accommodates a stage S in which the first and second materials M1 and M2 are accumulated from first and second discharge nozzles 20a, 10a that form the lower ends of the heating funnel 10 and the discharge unit 20, respectively, and provides an annealing space 50' for an object to be formed using the stage S as a support base. For example, in one embodiment of the present invention, the embedding block 40 and the heating chamber 50 may be vertically connected to each other through a discharge hole 40'' that allows the first and second materials M1 and M2 to flow from the first and second discharge nozzles 20a, 10a toward the annealing space 50' in which the stage S is accommodated.

[0062] In one embodiment of the present invention, the first and second materials M1, M2 discharged from the heating funnel 10 embedded in the embedding block 40 and the discharge unit 20 are accumulated on a stage S disposed in the slow cooling space 50' of the heating chamber 50, and in this manner, the embedding block 40 and the heating chamber 50 can be fluidly connected to each other to allow the flow of the first and second materials M1, M2. In this specification, when the embedding block 40 and the heating chamber 50 are fluidly connected to each other, it means that the first and second materials M1 and M2 from the heating funnel 10 embedded in the embedding block 40 and the discharge unit 20 can be accumulated on a stage S arranged in the heating chamber 50, and therefore when the embedding block 40 and the heating chamber 50 are fluidly connected to each other, it can mean that the internal space of the heating funnel 10 embedded in the embedding block 40 (the internal space of the heating funnel 10 containing the second material M2) and the internal space of the discharge unit 20 (the internal space of the discharge unit 20 containing the first material M1) are connected to the annealing space of the heating chamber 50 (50', the annealing space 50' containing the stage S), and that the internal space of the heating funnel 10, the internal space of the discharge unit 20, and the annealing space 50' of the heating chamber 50 are all connected to form a single space.

[0063] In an embodiment of the present invention, the annealing space 50' of the heating chamber 50, which provides a support base for the shaped object, may be sealed by assembling the embedding block 40 and the heating chamber 50. Here, sealing the annealing space 50' of the heating chamber 50 by assembling the embedding block 40 and the heating chamber 50 means that the embedding block 40 and the heating chamber 50 are fluidly connected to each other to form a single space, and the single space thus formed, for example, the inner space of the heating funnel 10 containing the second material M2, the inner space of the discharge unit 20 containing the first material M1, and the annealing space 50' of the heating chamber 50 in which the stage S is disposed, form a single space that is fluidly connected to each other, and the embedding block 40 and the heating chamber 50 are assembled to each other in the vertical direction Z1 to seal the single space. In one embodiment of the present invention, a sealing cover 1 is disposed over the inlet of the heating funnel 10 exposed at the upper end of the embedding block 40, sealing the inlet of the heating funnel 10. For example, the flow rate (volume passing through a cross-sectional area per unit time) or discharge speed of the second material M2 discharged from the internal space of the heating funnel 10 through the second discharge nozzle 10a forming the lower end of the heating funnel 10 can be controlled by the pressure of a gas RG filled in the internal space of the heating funnel 10 sealed by the sealing cover 1 that seals the internal space of the heating funnel 10. For example, in one embodiment of the present invention, the internal space of the heating funnel 10 is filled with a molten metal flowing from a metal block and a gas RG, such as a gas RG containing air, that applies a predetermined pressure to the liquid surface of the metal flow. In one embodiment of the present invention, the flow rate (volume passing through a cross-sectional area per unit time) or discharge speed of the second material M2 discharged from the second discharge nozzle 10a forming the lower end of the heating funnel 10 can be controlled by adjusting the pressure of the gas RG. For example, the gas RG filled in the internal space of the heating funnel 10 may contain a rare gas, which can prevent oxidation of the metal flow formed in the internal space of the heating funnel 10 while controlling the flow rate (volume passing through a cross-sectional area per unit time) or discharge speed of the metal flow.In this manner, in one embodiment of the present invention, the flow rate (volume passing through a cross-sectional area per unit time) or discharge speed of the second material M2 in a liquid phase can be controlled by the pressure of the gas RG filled in the internal space of the heating funnel 10, and the flow rate (volume passing through a cross-sectional area per unit time) or discharge speed of the first material M1 in a paste or slurry state can be controlled by the rotation speed of the rotary screw 85 rotated inside the transfer pipe 83 of the extrusion device 80. In this manner, in one embodiment of the present invention, the flow rates (volume passing through a cross-sectional area per unit time) or discharge speeds of the first and second materials M1 and M2, which form different contours and objects in different material phases, can be controlled by different control mechanisms.

[0064] In one embodiment of the present invention, the embedding block 40 and the heating chamber 50 form a single space fluidly connected to each other. For example, the single space may be sealed when the embedding block 40 and the heating chamber 50 are assembled. In one embodiment of the present invention, the internal space of the heating funnel 10, which is set to a second temperature T2 equal to or higher than the melting point of the metal block, the internal space of the discharge unit 20, which is set to a first temperature T1 lower than the melting point of the metal block and higher than room temperature, and the annealing space 50′, which accommodates a stage S on which the first and second materials M1 and M2 discharged from the first and second discharge nozzles 20a, 10a forming the lower ends of the heating funnel 10 and the discharge unit 20 are accumulated, form a single space connected to each other to allow the first and second materials M1 and M2 to flow, and the single space connected to each other may be insulated from the outside when the embedding block 40 and the heating chamber 50 are assembled. For example, the embedding block 40 and the heating chamber 50 may be hermetically coupled to each other through a stepped interface (stepped assembly portion ST1) to prevent internal hot air or external cold air from passing through. In one embodiment of the present invention, the embedding block 40 and the heating chamber 50 may be provided with different first and second heat sources 15, 55, e.g., first and second heat sources 15, 55 that are driven independently. This allows the second temperature T2 of the heating funnel 10 embedded in the embedding block 40, the first temperature T1 of the discharging unit 20, and the annealing temperature or third temperature T3 for annealing of the object formed on the stage S to be independently controlled. The embedding block 40 and the heating chamber 50 may also be hermetically coupled to each other through the stepped interface (assembly portions ST1, ST2) therebetween to hermetically seal a space formed by the embedding block 40 and the heating chamber 50, which are fluidly connected to each other for discharging the first and second materials M1 and M2, and to insulate the space from the surrounding environment.In this specification, when the embedding block 40 and the heating chamber 50 are assembled, the space formed by the embedding block 40 and the heating chamber 50, for example, the internal space of the heating funnel 10 embedded in the embedding block 40, the internal space of the discharge unit 20, and the cooling space 50' inside the heating chamber 50, is sealed into a single space fluidly connected to each other, or is insulated so that the outlets of hot and cold air are blocked from the surrounding environment, assuming, for example, that the inlet of the heating funnel 10 exposed at the top end of the embedding block 40 is sealed, and in one embodiment of the present invention, a sealing cover 1 may be placed on the inlet of the heating funnel 10. Meanwhile, the connecting pipe body 70 connected to the discharge port 80a of the extrusion device 80 is sandwiched between the fitting end 20b of the discharge unit 20 exposed at the upper end of the embedded block 40, so that the inlet of the heating funnel 10 exposed at the upper end of the embedded block 40 and the fitting end 20b of the discharge unit 20 can be insulated from the surrounding environment so that the outlet of internal hot air or external cold air is blocked through the inlet of the heating funnel 10 exposed at the upper end of the embedded block 40 and the fitting end 20b of the discharge unit 20.

[0065] In one embodiment of the present invention, the assembly of the embedding block 40 and the heating chamber 50 includes a hermetic connection between the embedding block 40 and the heating chamber 50. In one embodiment of the present invention, the embedding block 40 and the heating chamber 50 may be hermetically connected to each other via a stepped interface (assembly portions ST1, ST2). More specifically, the embedding block 40 may include an assembly portion ST1 with the heating chamber 50 formed on a bottom wall of the embedding block 40 (lower block 42) that defines the upper portion of the heating chamber 50, and the heating chamber 50 may include a partition wall 50a disposed to abut against the stepped surface of the assembly portion ST1. For example, in one embodiment of the present invention, the embedding block 40 may include an upper block 41 formed to a relatively high height to embed most of the heating funnel 10 and the discharge unit 20, and a lower block 42 formed with an area expanded from the upper block 41. An assembly portion ST1 for hermetic connection with the heating chamber 50 may be formed on the bottom of the lower block 42. For example, in one embodiment of the present invention, the assembly unit ST1 includes a stepped surface formed along the frame of the lower block 42. The partition wall 50a of the heating chamber 50 is assembled upright to abut against the stepped surface of the assembly unit ST1, thereby forming an annealing space 50' surrounded by the lower block 42 of the embedded block 40 and the partition wall 50a of the heating chamber 50. A second heat source 55 may be formed on the partition wall 50a of the heating chamber 50, which forms the annealing space 50'. The second heat source 55 is received in the receiving channel 50''' of the partition wall 50a, which forms the annealing space 50', and is formed to surround the stage S, which provides a support base for the object, and may control the cooling rates of the first and second materials M1 and M2 accumulated on the stage S from the first and second discharge nozzles 20a and 10a.More specifically, in one embodiment of the present invention, a solid object is formed by cooling the liquid metal flow filled in the filled space FS surrounded by the outline of the object formed in the first material M1. At this time, since local thermal stress may accumulate due to deviations in the cooling rate of the liquid metal flow forming the object itself, the temperature decrease profile per time (temperature profile of the third temperature T3) is controlled slowly to induce uniform cooling, and the second heat source 55 may control the temperature of the slow cooling space 50' (third temperature T3) that houses the stage S where the first and second materials M1 and M2 are accumulated so that an annealing heat treatment effect is achieved. In one embodiment of the present invention, the second heat source 55 controls the cooling rate of the liquid second material M2 so that the cooling rate of the second material M2 filling the filling space FS surrounded by the outline of the object formed in the first material M1 follows a slow profile per time (temperature profile of the third temperature T3), and by controlling the temperature (third temperature T3) of the slow cooling space 50' accommodating the stage S onto which the first and second materials M1, M2 are both ejected, the third temperature T3 of the slow cooling space 50' accommodating the stage S onto which the first and second materials M1, M2 are both ejected can be controlled so that a quenching heat treatment effect does not occur in the second material M2 that comes into contact with the first material M1 due to contact with the relatively low temperature first material M1 caused by contact between the first and second materials M1, M2. In one embodiment of the present invention, the second material M2, which is discharged at a second temperature T2 that is equal to or higher than the melting point of the metal block, is liquid and has relatively high fluidity, whereas the first material M1, which is in a paste or slurry state with ceramic particles dispersed therein, has relatively low fluidity. Therefore, the temperature of the first material M1 or the discharge unit 20 containing the first material M1 is set to a first temperature T1 that is lower than the second temperature T2, and may be set to a sufficiently low temperature to prevent evaporation or volatilization of the matrix in which the ceramic particles are dispersed (e.g., water (H2O) as a vehicle for giving fluidity to the ceramic particles).For example, in one embodiment of the present invention, the first temperature T1 of the first material M1 and the second temperature T2 of the second material M2 discharged onto the stage S satisfy the relationship of second temperature T2 > first temperature T1, where the first temperature T1 is low enough to prevent the matrix of the first material M1 from evaporating or volatilizing, and the third temperature T3 of the slow cooling space 50' may be set higher than the first temperature T1 so as to form the outline of a solid or near-solid object through the evaporation or volatilization of the matrix in which ceramic particles are dispersed. For example, in one embodiment of the present invention, the first temperature T1 of the first material M1 to be dispensed onto the stage S or the dispensing unit 20 accommodating the first material M1, the second temperature T2 of the heating funnel 10 accommodating the second material M2 to be dispensed onto the stage S, and the third temperature T3 of the annealing space 50′ accommodating the stage S may satisfy the magnitude relationship of second temperature T2 > third temperature T3 > first temperature T1. In one embodiment of the present invention, the second temperature T2 corresponds to the highest temperature above the melting point of a metal block in a 3D printing device including different spaces set with different target temperatures (e.g., first to third temperatures T1 to T3), and may be maintained constant over time using the target temperature above the melting point of the metal block as an input, and may be maintained at a temperature determined by controlling the first heat source 15. The first temperature T1 of the discharge unit 20, which is embedded together with the first heat source 15 as a heat supply source and is separated from the heating funnel 10 or the first heat source 15 surrounding the outer surface of the heating funnel 10 across the thermal resistance formed by the insulating material of the embedded block 40 that embeds the gap g between the first and second discharge nozzles 20a, 10a, is maintained constant over time similar to the second temperature T2, for example, the first temperature T1 of the discharge unit 20 can also be maintained constant over time due to the insulating material of the embedded block 40 that embeds the gap g between the first and second discharge nozzles 20a, 10a, so as to provide a constant second temperature T2 and a constant thermal resistance.

[0066] Unlike the first and second temperatures T1 and T2 of the heating funnel 10 and the discharge unit 20, the third temperature T3 of the slow cooling space 50' of the heating chamber 50 is controlled to have a slow temperature profile over time and is set to a temperature that gradually decreases according to a temperature profile that is changed over time to induce an annealing heat treatment effect while following a predetermined slow temperature profile through control of the second heat source. Thus, unlike the first and second temperatures T1 and T2, the third temperature T3 of the slow cooling space 50' of the heating chamber 50 may correspond to a temperature that changes over time. As described above, the first to third temperatures T1 to T3 satisfy the magnitude relationship of second temperature T2 > third temperature T3 > first temperature T1, and in this case, the third temperature T3 may correspond to the highest temperature in the slowly decreasing temperature profile over time. For example, in one embodiment of the present invention, the slow cooling space 50' of the heating chamber 50 may be maintained at a constant third temperature T3 during a period in which the first material M1 is being dispensed, and may be maintained at a relatively high temperature suitable for vaporizing or volatilizing the matrix of the first material M1 dispensed onto the stage S. The third temperature T3 may be gradually lowered as the slow cooling period begins. In this case, the third temperature T3 may be maintained at the highest temperature suitable for vaporizing or volatilizing the matrix of the first material M1 during a period in which the first material M1 is being dispensed onto the stage S (or a period in which at least one of the first and second materials M1 and M2 is being dispensed), and the slow cooling period in which the third temperature T3 is gradually lowered may begin only after the dispensing of the first material M1 is completed, the dispensing of the second material M2 that fills the filling space FS surrounded by the outline of the object made of the first material M1 is completed, and the outer appearance of the object is substantially formed.On the other hand, if the third temperature T3 of the slow cooling space 50' of the heating chamber 50 accommodating the stage S is lowered during the period in which the first and second materials M1 and M2 are continuously being discharged onto the stage S, the slow temperature profile of the slow cooling will be contrary to the objective of inducing uniform cooling within the object and eliminating thermal stress or residual stress due to deviations in the cooling rate. In fact, this may induce deviations in the cooling rate within the object depending on the stacking order of each layer (e.g., each layer of the second material M2) discharged onto the stage S, resulting in thermal stress or residual stress.

[0067] A 3D printing apparatus according to one embodiment of the present invention includes different spaces controlled to different first to third temperatures T1 to T3, and the first to third temperatures T1 to T3 have the magnitude relationship described above. In this case, the first and second temperatures T1 and T2 may be maintained constant over time, while the third temperature T3 follows a slow temperature profile for slow cooling of the object. In this case, the third temperature T3, which is compared with the first and second temperatures T1 and T2 maintained constant, may correspond to the highest temperature in the slow temperature profile for slow cooling (e.g., the highest temperature maintained during the period in which the discharge of the first and second materials M1 and M2 continues).

[0068] As described above, the embedded block 40 and the heating chamber 50, which are assembled along the vertical direction Z1, are fluidly connected to each other to allow the discharge of the first and second materials M1 and M2. More specifically, the embedded block 40 and the heating chamber 50 are fluidly connected to each other via discharge holes 40'' to allow the discharge of the first and second materials M1 and M2. The discharge holes 40'' are formed in a lower block 42 connected to an upper block 41 that embeds most of the heating funnel 10 and the discharge unit 20, and may include two different discharge holes 40'' connected to the first and second discharge nozzles 20a, 10a that form the lower ends of the respective heating funnels 10 and discharge units.

[0069] In one embodiment of the present invention, the embedding block 40 may include an upper block 41 formed at a relatively high height to embed most of the heating funnel 10 and the discharge unit 20, and a lower block 42 having an extended area at a relatively low height below the upper block 41 and for covering the annealing space 50' of the heating chamber 50. For example, in one embodiment of the present invention, the upper block 41 and the lower block 42 may be formed in a substantially hexahedral shape and may include the upper block 41 formed at a relatively high height and the lower block 42 having a plate shape extended at a relatively low height from the upper block 41.

[0070] The first material M1 may be a paste or slurry composite material containing solid ceramic particles and a liquid matrix in which the ceramic particles are dispersed. For example, the ceramic particles may have a particle size on the micrometer scale. In one embodiment of the present invention, the ceramic particles may include a mixture of ceramic particles having different sizes. The mixture of ceramic particles of different sizes provides appropriate voids between the ceramic particles of different sizes to accommodate the matrix. The ceramic particles of different sizes accumulated on the stage S fill the voids, e.g., the smaller ceramic particles fill the voids between the larger ceramic particles. This mixture of ceramic particles of different sizes may form the outline of a shaped object with strong shape stability (e.g., height stability due to the interlocking of particles of different sizes filling the voids) through evaporation or volatilization of the matrix. Meanwhile, in one embodiment of the present invention, the first material M1 may include water (H2O) as a matrix to accommodate the solid ceramic particles and the dispersed ceramic particles. In one embodiment of the present invention, the matrix may provide fluidity to the ceramic particles, including the dispersed ceramic particles. Such a first material M1 may be formed in a paste or slurry state with dispersed ceramic particles and have lower fluidity than a second material M2, which is formed of a liquid metal or metal flow. The first material M1 may be forcibly transported through a dispensing unit 20 including a first dispensing nozzle 20a at its lower end from which the first material M1 is dispensed and a connecting pipe 70 connected to a fitting end 20b of the dispensing unit 20, so as to form a homogeneous mixture (or a homogeneous dispersion) between the ceramic particles (solid phase) and the matrix (liquid or gel phase) containing the ceramic particles, which have different material phases.

[0071] In one embodiment of the present invention, a low-melting-point metal block serving as the raw material (second raw material) of the second material M2 is placed in a heating funnel 10 connected to a second discharge nozzle 10a from which the second material M2 is discharged, and the heating funnel 10 is heated to a temperature above the melting point of the metal block, thereby forming a liquid metal flow that forms the second material M2. For example, in one embodiment of the present invention, the low-melting-point metal block serving as the raw material (second raw material) of the second material M2 has a slim, circular disk shape with a short height, and the longest dimension of the low-melting-point metal block corresponds to the diameter of the disk, with the diameter of the low-melting-point metal block being approximately 50 mm. In one embodiment of the present invention, the heating funnel 10, which receives the low-melting-point metal block as an input and discharges the metal flow, is substantially Y-shaped, and the inner diameter of the second discharge nozzle 10a from which the metal flow is discharged is smaller than the inner diameter of the inlet through which the low-melting-point metal block is introduced. In other words, the inner diameter of the inlet through which the low-melting-point metal block is introduced is larger than the longest dimension of the low-melting-point metal block. Conversely, the inner diameter of the second discharge nozzle 10a from which the metal flow formed by melting the low-melting-point metal block in the heating funnel 10 is discharged can be smaller than the longest dimension of the low-melting-point metal block. More specifically, when the longest dimension of the low-melting point metal block corresponds to the diameter of the disk-shaped low-melting point metal block and the diameter of the disk is formed to be approximately 50 mm, in one embodiment of the present invention, the inner diameter of the second discharge nozzle 10a is formed to be 0.1 mm to 4 mm, which is smaller than the diameter of the solid-phase disk, 50 mm, and can be formed to be, for example, approximately 1 mm to 2 mm.

[0072] In one embodiment of the present invention, the first and second discharge nozzles 20a, 10a may be embedded and fixed in position within a single embedding block 40 at a predetermined interval, and the first and second discharge nozzles 20a, 10a may be positioned adjacent to each other via the embedding block 40. For example, the heating funnel 10 and the discharge unit 20, each including the first and second discharge nozzles 20a, 10a at their lower ends facing the stage S, may be disposed at a predetermined interval within the embedding block 40. For example, the heating funnel 10 may be Y-shaped and the discharge unit 20 may extend in a diagonal direction parallel to the outer circumferential surface of the heating funnel 10, simultaneously following the height direction Z1 and the radial directions Z2 and Z3, so as to maintain a predetermined interval at different levels along the height direction Z1. For example, in one embodiment of the present invention, the outer circumferential surface of the heating funnel 10 and the discharge unit 20 may extend along a diagonal line that simultaneously follows the height direction Z1 and the radial directions Z2 and Z3, and may form first and second discharge nozzles 20a, 10a at their lower ends that extend vertically along the height direction Z1 toward the stage S. For example, the heating funnel 10 may form a bottleneck deformation point to which the second discharge nozzle 10a is connected, and the discharge unit 20 may form a bent deformation point to which the first discharge nozzle 20a is connected.

[0073] In one embodiment of the present invention, the distance g between the first and second discharge nozzles 20a, 10a secured from the embedding block 40 is formed to be approximately 3 mm to 50 mm, and for example, the distance g between the first and second discharge nozzles 20a, 10a may be formed to be approximately 25 mm. As will be described later, in one embodiment of the present invention, the distance g between the first and second discharge nozzles 20a, 10a secured by the embedding block 40 depends on the drive mode of the first and second discharge nozzles 20a, 10a. For example, unlike a drive mode in which the first and second discharge nozzles 20a, 10a are operated in chronological order, in a drive mode in which the first and second discharge nozzles 20a, 10a are operated simultaneously, the distance formed between the discharge positions P1, P2 of the first and second material M1, M2 discharged from the first and second discharge nozzles 20a, 10a is filled by the metal flow of the liquid phase of the second material M2 discharged from the second discharge nozzle 10a according to the distance between the first and second discharge nozzles 20a, 10a. For example, the distance between the first and second discharge positions P1, P2 can be filled by the metal flow of the second material M2 flowing from the second discharge position P2 of the second material M2 toward the first discharge position P1 of the first material M1. For example, in one embodiment of the present invention, the first and second materials M1 and M2, which respectively form the outline of the object and the object itself, are ejected together onto the stage S by simultaneous movement of the first and second ejection nozzles 20a and 10a. Unlike the first material M1, which lacks fluidity, the second material M2, which has relatively high fluidity, flows from the ejection position P2 of the second material M2 toward the ejection position P1 of the first material M1, filling the filling space FS surrounded by the outline of the object formed from the first material M1, without forming an empty space (void) inside the object.In this manner, in a driving mode in which the first and second discharge nozzles 20a, 10a are simultaneously operated, the first and second materials M1, M2 discharged from the first and second discharge nozzles 20a, 10a come into contact with each other, and thus, in one embodiment of the present invention, the first and second temperatures T1, T2 of the first and second materials M1, M2 can be controlled through the embedding block 40 that embeds the heating funnel 10 and discharge unit 20, including the first and second discharge nozzles 20a, 10a at the lower ends from which the first and second materials M1, M2 are discharged, and through the embedding block 40 that embeds the first heat source 15 together with the heating funnel 10 and discharge unit 20. In other words, the first and second temperatures T1, T2, which are higher than room temperature but different from each other, can be controlled by the movement of the first heat source 15 and the insulating material of the embedding block 40 interposed between the heating funnel 10 and the discharge nozzle (preventing rapid cooling of the second material M2 due to contact between the first and second materials M1, M2).

[0074] For example, in a drive mode in which the first and second discharge nozzles 20a, 10a are simultaneously operated, the distance g between the first and second discharge nozzles 20a, 10a is determined by the flow characteristics of the second material M2, such as the fluidity of the second material M2 discharged from the second discharge nozzle 10a (e.g., the viscosity or viscosity of the second material M2, which determines the fluidity) and the flow rate of the second material M2 (e.g., the inner diameter of the second discharge nozzle 20a and the pressure of the second discharge nozzle 20a, which determine the flow rate). For example, the distance g between the first and second discharge nozzles 20a, 10a is designed to increase as the fluidity and flow rate of the second material M2 increase. Even if the distance g between the first and second discharge nozzles 20a, 10a increases slightly, the distance between the discharge positions P1, P2 of the first and second materials M1, M2, which corresponds to the distance g between the first and second discharge nozzles 20a, 10a, can be sufficiently satisfied due to the relatively high fluidity and flow rate. Conversely, the gap g between the first and second discharge nozzles 20a, 10a is designed to decrease as the fluidity and flow rate of the second material M2 decrease, and the gap g between the first and second discharge nozzles 20a, 10a can be formed sufficiently narrow so that the gap between the discharge positions P1, P2 of the first and second materials M1, M2 corresponding to the gap g between the first and second discharge nozzles 20a, 10a can be fully filled despite the relatively low fluidity and flow rate of the second material M2.

[0075] In one embodiment of the present invention, the fluidity of the second material M2 is controlled by a first heat source 15 that uses a metal block as an input to form the liquid second material M2, and the flow rate of the second material M2 can be controlled by the pressure of gas RG injected into the inlet of a heating funnel 10 including a second discharge nozzle 10a at the lower end through which the second material M2 is discharged, or by the pressure of gas RG applied to the liquid surface of the second material M2 at the inlet. For example, in one embodiment of the present invention, a sealing cover 1 is placed over the inlet of the heating funnel 10, and gas RG to prevent oxidation of the second material M2 can be injected between the sealing cover 1 and the liquid surface of the second material M2 filled in the inlet. The flow rate of the second material M2 discharged from the second discharge nozzle 10a can be controlled by controlling the pressure of gas RG that pressurizes the liquid surface of the second material M2 toward the second discharge nozzle 10a.

[0076] In one embodiment of the present invention, it is required to satisfy the distance between the discharge positions P1, P2 of the first and second materials M1, M2 formed by the distance g between the first and second discharge nozzles 20a, 10a so as to prevent the occurrence of empty spaces (voids) in the object to be formed, and the distance g between the first and second discharge nozzles 20a, 10a can be designed to be sufficiently narrow so as to satisfy the distance between the discharge positions P1, P2 of the first and second materials M1, M2 based on the fluidity and flow rate of the second material M2 discharged from the second discharge nozzle 10a.

[0077] In one embodiment of the present invention, the distance g between the first and second discharge nozzles 20a, 10a may be designed to be sufficiently narrow to reduce the maximum stroke (travel) required to translate the stage S along a two-dimensional plane so as to control the first and second discharge positions P1, P2 of the first and second materials M1, M2 discharged from the first and second discharge nozzles 20a, 10a onto the stage S to the first and second target positions, respectively, using sliced ​​section data of the 3D object to be formed as input. In one embodiment of the present invention, to form the same object, the first discharge position P1 of the first material M1 for forming the outline of the object on the stage S and the second discharge position P2 of the second material M2 for forming the object itself are controlled to the same first and second target positions, respectively, and the stroke (travel) of the stage S for controlling the first and second discharge positions P1, P2 to the same first and second target positions may increase as the distance g between the first and second discharge nozzles 20a, 10a increases. That is, as the distance g between the first and second discharge nozzles 20a, 10a increases, the stroke of the stage S required to manufacture the same object needs to be extended to a wider span, and conversely, as the distance g between the first and second discharge nozzles 20a, 10a decreases, the stroke of the stage S required to manufacture the same object needs to be reduced to a narrower span, i.e., an object with a larger volume can be manufactured for the same stroke of the stage S. For example, extending the stroke of the stage S to a wider span means that the drive width or span of the second and third actuators A2, A3 for translating the stage S on a two-dimensional plane needs to be extended, and also means that the size of the annealing space 50' that houses the stage S needs to be expanded. As a result, the cost of the printing apparatus increases even though it has the same production capacity to form objects of the same size.For example, when the distance g between the first and second discharge nozzles 20a, 10a is designed to be different from each other, the amount of movement of the stage S required for the second discharge nozzle 10a to move to the target position where the first discharge nozzle 20a is located, or for the second discharge nozzle 10a to move to the target position on the stage S opposite the first discharge nozzle 20a, can be further reduced as the distance between the first and second discharge nozzles 20a, 10a becomes narrower (see FIG. 14).

[0078] In one embodiment of the present invention, the thermal resistance of the insulating material of the embedded block 40 that embeds the gap g between the first and second discharge nozzles 20a, 10a changes depending on the gap g between the first and second discharge nozzles 20a, 10a, which can affect the temperature difference between the first and second temperatures T1, T2 of the heating funnel 10 and the discharge unit 20, including the first and second discharge nozzles 20a, 10a at the lower ends from which the first and second materials M1, M2 are discharged. For example, the second temperature T2 of the heating funnel 10 can be directly controlled from the first heat source 15 surrounding the outer surface of the heating funnel 10, while the first temperature T1 of the discharge unit 20 can be indirectly controlled by the distance from the heating funnel 10 or the distance from the first heat source 15 surrounding the outer surface of the heating funnel 10, and the first temperature T1 of the discharge unit 20 can be controlled by the distance between the heating funnel 10 and the discharge unit 20, which extend parallel to each other, or the distance between the first and second discharge nozzles 20a, 10a forming the lower ends of each heating funnel 10 and the discharge unit 20. In one embodiment of the present invention, the first temperature T1 of the discharge unit 20 from which the first material M1 is discharged is formed at a temperature that is low enough to suppress evaporation or volatilization of the matrix contained in the first material M1, and at a temperature that is high enough not to rapidly cool the second material M2 that forms the object itself while in contact with the first material M1 that forms the outline of the object on the stage S, and the distance g between the first and second discharge nozzles 20a, 10a can be appropriately designed in order to control the first temperature T1 of such first material M1 to an appropriate level. For example, the spacing g between the first and second discharge nozzles 20a, 10a can be determined from different perspectives, such as: 1) designing the spacing g between the first and second discharge nozzles 20a, 10a to be sufficiently narrow so as to shorten the stroke (travel) of the stage S for forming the same object, and, as a compromise, 2) appropriately designing the thermal resistance of the insulating material of the embedding block 40 embedded between the first and second discharge nozzles 20a, 10a, for example, to form the spacing g between the first and second discharge nozzles 20a, 10a to be sufficiently wide so as to suppress evaporation or volatilization of the matrix contained in the first material M1 (suppressing evaporation or volatilization of the matrix due to an excessively high first temperature T1).

[0079] In one embodiment of the present invention, the heating funnel 10, which receives a solid metal block as input and discharges a liquid metal flow, may have a substantially Y-shaped funnel shape, with the inner diameter of the second discharge nozzle 10a, from which the liquid metal flow is discharged, being smaller than the inner diameter of the inlet through which the solid metal block is introduced. In one embodiment of the present invention, the Y-shaped funnel shape of the heating funnel 10 may mean that the cross-sectional area decreases from the inlet forming the upper end of the heating funnel 10 to the second discharge nozzle 10a forming the lower end of the heating funnel 10, and that the heating funnel 10 has a funnel shape with a circular cross section from the inlet at the upper end to the second discharge nozzle 10a at the lower end. For example, in one embodiment of the present invention, the second discharge nozzle 10a may discharge the second material M2 through a circular cross-sectional area whose inner diameter may be defined. For example, the heating funnel 10 may be formed in such a manner that the inner diameter gradually decreases from the inlet at the upper end to the second discharge nozzle 10a at the lower end along the height direction Z1, forming a bottleneck having the smallest inner diameter at the second discharge nozzle 10a, and the second discharge nozzle 10a may be formed to have a constant inner diameter.

[0080] In one embodiment of the present invention, a first heat source 15 for heating a metal block placed in the heating funnel 10 to above its melting point may be wound around the outer periphery of the heating funnel 10. In one embodiment of the present invention, the first heat source 15 wound around the outer periphery of the heating funnel 10 may generate a second temperature T2 that is the highest temperature above the melting point of the metal block, and a second heat source 55 formed in a heating chamber 50 accommodating a stage S from which the second material M2 is discharged through the heating funnel 10 may generate a third temperature T3 that is lower than the second temperature T2. For example, in one embodiment of the present invention, the second temperature T2 may be set to be above the melting point of the metal block, and the third temperature T3 may be set to be lower than the second temperature T2 and high enough to vaporize or volatilize a matrix containing a plurality of ceramic particles dispersed to form the first material M1 in a paste or slurry state. The first temperature T1 of the discharge unit 20 containing the first material M1 is set to a temperature lower than the second temperature T2 and the third temperature T3, and higher than room temperature, but low enough to suppress evaporation or volatilization of the matrix that provides the fluidity of the first material M1. For example, the first temperature T1 may be maintained at a temperature lower than the third temperature T3 in the heating chamber 50, which can induce evaporation or volatilization of the matrix from the first material M1 accumulated on the stage S.

[0081] In one embodiment of the present invention, the heating funnel 10 may be made of a ceramic material having electrical insulation, thermal insulation, and fire resistance. The first heat source 15 may be wound around the outer periphery of the heating funnel 10, and may be wound continuously along the outer periphery of the heating funnel 10 in a spiral shape. For example, the first heat source 15 may be a heating wire wound around the outer periphery of the heating funnel 10. In one embodiment of the present invention, a concave receiving channel 40' for receiving the heating wire forming the first heat source 15 may be formed on the outer periphery of the heating funnel 10 and / or in the embedding block 40 facing the outer periphery of the heating funnel 10, and the concave receiving channel 40' may be formed in a spiral shape continuously along the outer periphery of the heating funnel 10. In one embodiment of the present invention, the first heat source 15 is provided on a heating wire wound around the outer periphery of the heating funnel 10. By being wound around the outer periphery of the electrically insulating heating funnel 10, the flow of the metal flow contained within the heating funnel 10 can be prevented from being disturbed by the current in the heating wire or the electromagnetic force induced by the current. For example, in one embodiment of the present invention, the heating funnel 10 forms electrical insulation between the internal space of the heating funnel 10 filled with the second material M2 and the outer periphery of the heating funnel 10 around which the first heat source 15 is wound, thereby providing insulation to eliminate electromagnetic influences between the flow of the metal flow filled in the internal space of the heating funnel 10 and the heating wire wound around the outer periphery of the heating funnel 10, for example, electromagnetic influences that could disturb the flow of the metal flow.

[0082] The first heat source 15 is connected to a first switch to control the temperature (second temperature T2) of the inner space of the heating funnel 10, and the temperature of the inner space of the heating funnel 10 can be set to the second temperature T2, which is higher than the melting point of the metal block, by turning on / off the operation of the heating wire through on / off control of the first switch. For example, the first heat source 15 may have a different configuration from the conductor to which the AC current is applied in order to generate an electromagnetic force through the flow of the AC current and induce an intermittent flow of the second discharge nozzle 10a forming the lower end of the heating funnel 10, for example, to induce droplet-shaped droplets.

[0083] Like the heating funnel 10, the embedding block 40 may be made of a ceramic material having electrical insulation, thermal insulation, and fire resistance. The embedding block 40 may have a substantially hexahedral shape, and may include an upper block 41 formed at a relatively high height so as to embed most of the heating funnel 10 and the discharge unit 20, and a lower block 42 formed on a plate with an area expanded from the upper block 41. An extrusion device 80 connected to the discharge unit 20 via a connecting pipe 70 may be disposed in a stepped region between the upper block 41 and the lower block 42 of the embedding block 40, i.e., in a stepped region formed between the top surface of the lower block 42 and the side surface of the upper block 41.

[0084] The lower block 42 may form an annealing space 50' together with the partition wall 50a of the heating chamber 50 and, more specifically, define the upper portion of the annealing space 50'. For example, the four frames of the lower block 42 may have stepped mounting portions ST1 formed thereon to form stepped interfaces with the partition wall 50 of the heating chamber 50. For example, the upper corners of the partition wall 50a of the heating chamber 50 may be assembled to abut against the stepped mounting portions ST1 of the lower block 42, thereby forming a hermetic connection between the heating chamber 50 and the lower block 42 via the stepped interfaces. Meanwhile, in one embodiment of the present invention, the heating chamber 50 includes a total of four partition walls 50a arranged to face each other along different second and third directions Z2 and Z3. The partition walls 50a, which are assembled to abut against each other and form corners, may also form stepped interfaces with each other via the stepped mounting portions ST2 to form a hermetic connection.

[0085] The heating chamber 50 may be made of a ceramic material having electrical insulation, thermal insulation, and fire resistance. The heating chamber 50 may have a substantially hexahedral shape, and a stage S may be accommodated in the annealing space 50' of the hexahedral heating chamber 50, where the first and second materials M1 and M2 discharged from the first and second discharge nozzles 20a and 10a are accumulated. The heating chamber 50 may include four partition walls 50a surrounding the annealing space 50'. The four partition walls 50a forming the heating chamber 50 may be assembled to abut against the assembly portion ST1 of the lower block 42, which defines the upper portion of the annealing space 50', thereby forming the heating chamber 50 that provides the annealing space 50'. The heating chamber 50 may further include a bottom wall 50b that defines the lower portion of the annealing space 50' and provides an assembly position for the four partition walls 50a to be placed. An opening 50'' is formed in the bottom wall 50b of the heating chamber 50 to allow power connection between the stage S and the actuator A (first to third actuators A1 to A3), and a connecting rod 100 that power connects the stage S and the actuator A that provides driving power to the stage S can pass through the opening 50'', thereby power connecting the stage S and the actuator A to each other.

[0086] A connecting rod 100, which power-couples the stage S and the actuator A (first through third actuators A1 to A3), can generate three-dimensional movement of the stage S by following both the up-and-down movement and the translational movement on a two-dimensional plane of the actuator A. In this case, a link structure L connected to the bellows cover ZC overlaps the guide block GB (e.g., the guide block GB of the third actuator A3) which moves up and down by driving the actuator A (first through third actuators A1 to A3) and the bellows cover ZC which seals the opening 50″ of the bottom wall 50b of the heating chamber 50, adaptively expanding and contracting the distance between the guide block GB and the bellows cover ZC, which is superimposed on the bottom wall 50b of the heating chamber 50 and seals the opening 50″ of the bottom wall 50b, regardless of the driving of the actuator A (first through third actuators A1 to A3), thereby blocking the outlet of internal hot air and external cold air.

[0087] The opening 50'' formed in the bottom wall 50b of the heating chamber 50 is sealed by a bellows cover ZC covering the opening 50'' regardless of the lifting and lowering operation of the actuator A. The bellows cover ZC extends parallel to the connecting rod 100 connecting the actuator A (e.g., the guide block GB of the third actuator A3) and the stage S, and is connected to a link structure L that adaptively expands and contracts between the actuator A (e.g., the guide block GB of the third actuator A3) and the bottom wall 50b of the heating chamber 50, allowing the opening 50'' to be sealed regardless of the lifting and lowering operation of the actuator A.

[0088] Although not shown in the drawings, the discharge unit 20 embedded in the embedding block 40 together with the heating funnel 10 may be made of different materials, for example, a core portion that forms the exterior of the discharge unit 20 and a ceramic-based shell portion that surrounds the core portion may be made of different materials. In one embodiment of the present invention, the metallic core portion forms the framework of the discharge unit 20, forms a smooth surface (or inner diameter) for discharging the first material M1, and is made of a metallic material such as stainless steel that has excellent formability, and the shell portion that surrounds the metallic core portion may be made of a ceramic-based material that has electrical insulation, thermal insulation, and fire resistance. In one embodiment of the present invention, the discharge unit 20 has a core made of a metal material, and heat is transferred from a first heat source 15 surrounding the outer circumferential surface of the heating funnel 10 to maintain the temperature of the discharge unit 20 at a first temperature T1 higher than room temperature. A ceramic shell surrounds the core, and the ceramic shell is made of the same or similar ceramic material as the embedding block 40 in which the discharge unit 20 is embedded together with the heating funnel 10. This allows the discharge unit 20 and the heating funnel 10 to form intimate contact with each other, essentially eliminating separation problems between different materials due to their different material properties. For example, in one embodiment of the present invention, the heating funnel 10 and the discharge unit 20 embedded in the embedding block 40 are made of the same or similar ceramic material as the embedding block 40, thereby preventing separation problems between different materials with different material properties. Similarly, the embedding block 40 and the heating chamber 50, which together form the annealing space 50' of the heating chamber 50 through intimate contact with each other, can be made of the same or similar ceramic material, thereby blocking the flow of hot and cold air between the inside and outside of the annealing space 50' through their intimate contact with each other.

[0089] In one embodiment of the present invention, the embedding block 40 and the heating chamber 50 may be hexahedral to form a tight connection with each other. In various embodiments of the present invention, the embedding block 40 and the heating chamber 50 may be various polygonal or rounded shapes other than hexahedral. In one embodiment of the present invention, the heating chamber 50 may accommodate a stage S that provides a support base for the object and provide a location for cooling the object formed on the stage S. In one embodiment of the present invention, the object may be formed by heating and melting a low-melting-point metal block as the second material M2 that forms the object itself, and then filling the filled space FS surrounded by the outline of the object made of the first material M1 with the formed metal. The liquid metal filling the filled space FS surrounded by the outline of the first material M1 may then be cooled, more specifically, slowly cooled, to form a solid object. By cooling the liquid metal flow to form a solid-phase object in this manner, internal defects such as empty spaces (voids) inside the object are eliminated. For example, compared to a comparative example in which the second material M2 that forms the object itself is ejected onto a stage S in a paste or slurry state formed by mixing metal powder, a vehicle to impart fluidity, and a binder to control viscosity to form the exterior of the object, and then a laser is irradiated to sinter the paste or slurry second material M2 to complete a solid-phase object, an object with reduced internal defects such as empty spaces (voids) can be formed.

[0090] In one embodiment of the present invention, a liquid metal flow is filled into a fill space FS surrounded by a first material M1 that forms the outline of the object, and the liquid metal flow is cooled to form a solid object, thereby forming an object with reduced internal defects such as voids. The object is cooled in a heating chamber 50 that can control the third temperature T3 of the slow cooling space 50' to control the cooling rate of the object formed from the liquid metal flow. The slow cooling of the object is induced by controlling the third temperature T3 of the slow cooling space 50' in the heating chamber 50, which houses a stage S that provides a support base for the object. By controlling the cooling rate of the object and cooling the object at a relatively low cooling rate sufficient for annealing, residual stresses such as thermal stress that may accumulate inside the object due to cooling deviations depending on the position of the object can be eliminated. For example, the cooling rate at which an annealing heat treatment is performed refers to a temperature profile with a relatively gradual decrease per time, whereas the cooling rate at which a quenching heat treatment is performed refers to a temperature profile with a steep decrease per time. If the cooling rate of the object is not controlled, unlike the present invention, for example, if the object is cooled gradually at a gradual temperature profile, but rather rapidly at a rapid temperature profile, as occurs when the object is cooled at room temperature, the object will be subjected to a quenching heat treatment rather than an annealing heat treatment. This will induce thermal stress or residual stress due to local temperature deviations within the object, and the quenching heat treatment will make the object very brittle and susceptible to external impacts, making it easily cracked or damaged by external impacts. In one embodiment of the present invention, a solid-phase object is formed by slowly cooling the object, and the cooling rate of the object is controlled to a slow temperature profile for annealing heat treatment, so that the object is cooled to a relatively uniform temperature without causing temperature deviations inside the object. As a result, the object does not cause residual stress such as thermal stress, and can be given strong toughness against external impact, resulting in a formed object with excellent impact resistance.

[0091] In one embodiment of the present invention, slow cooling is performed with a slow temperature profile for annealing heat treatment, and for this purpose, the temperature (corresponding to a third temperature T3) of the internal space of the heating chamber 50 housing the stage S where cooling is performed may be controlled. In another embodiment of the present invention, a second heat source 55 is provided within the heating chamber 50, and the object may be slowly cooled at a controlled cooling rate by operating the second heat source 55. For example, in one embodiment of the present invention, the first heat source 15 and the second heat source 55 are operated simultaneously or nearly simultaneously, thereby heating and maintaining the temperature (corresponding to a second temperature T2) of the internal space of the heating funnel 10 at a high temperature above the melting point of the metal block from the first heat source 15, and the second heat source 55 may slowly cool the liquid metal flow discharged from the heating funnel 10 with a slow temperature profile. For example, in various embodiments of the present invention, the first and second heat sources 15, 55 may be operated in chronological order. For example, the first and second heat sources 15, 55 may be operated or started to operate simultaneously or almost simultaneously so as not to delay the temperature control (temperature control for the third temperature T3) of the annealing space 50' containing the metal flow of the molten second material M2 from the first heat source 15. The first and second heat sources 15, 55 may be operated simultaneously to prevent rapid cooling of the second material M2 discharged onto the stage S contained in the annealing space 50' and to provide a temperature environment suitable for vaporizing or volatilizing the matrix of the first material M1. However, the first and second heat sources 15, 55 have different target set temperatures. For example, the first heat source 15 may be controlled to target a constant second temperature T2 that is higher than the melting point of the metal block, while the second heat source 55 may be controlled to target a different third temperature T3 along a slow temperature profile over time to control the cooling rate of the object. Therefore, in one embodiment of the present invention, the first and second heat sources 15, 55 may be driven independently of each other.

[0092] The second heat source 55 may be operated separately from the first heat source 15 to cool the internal temperature of the heating chamber 50 at a slow cooling rate suitable for annealing heat treatment. For example, in one embodiment of the present invention, the first heat source 15 and the second heat source 55 may be connected to separate first and second switches, respectively, for on / off control, and PID control may be performed on the first heat source 15 and the second heat source 55 using a preset constant second temperature T2 or a temperature calculated from a preset cooling rate (time-varying third temperature T3) as a target temperature value.

[0093] In one embodiment of the present invention, the first heat source 15 is operated to dispense the second material M2 in a metal flow state and form a solid-phase object by slowly cooling the second material M2 accumulated on the stage S. This dispensing of the second material M2 forms the object itself, i.e., melting a metal block as the second material M2. The second heat source 55 is operated to slowly cool the second material M2 accumulated on the stage S. In various embodiments of the present invention, the first and second heat sources 15 and 55 may be operated simultaneously or sequentially. After the second material M2 fills the filling space FS surrounded by the outline of the object formed on the stage S from the first material M2, completing the shape of the object, i.e., after the dispensing of the second material M2 from the heating funnel 10 is completed, the operation of the first heat source 15 is terminated. However, the operation of the second heat source 55 may continue to control the cooling rate of the slowly cooling space 50' of the object. For example, in one embodiment of the present invention, the first and second heat sources 15, 55 may be operated simultaneously, or the operation of the second heat source 55 may be continued while the operation of the first heat source 15 is stopped. In other words, during the takt time for completing one object, the operation time of the first heat source 15 (first operation time) and the operation time of the second heat source 55 (second operation time) may have the following magnitude relationship (first operation time<second operation time). For example, the second heat source 55 may be operated during the entire takt time of 3D printing, while the first heat source 15 may be operated for a shorter time than the entire takt time of 3D printing. For example, in one embodiment of the present invention, the operating time (second operating time) of the second heat source 55 includes a slow cooling time for slowly cooling the object to follow a slow temperature profile, and since the slow cooling time accounts for a significant proportion of the overall cycle time, it can be set longer than the operating time (first operating time) of the first heat source 15, which does not include such a slow cooling time.

[0094] Similar to the first heat source 15, the second heat source 55 is connected to a second switch to control a third temperature T3 of the interior space of the heating chamber 50, and the second switch can be turned on / off to control the operation of the heating wire, thereby controlling the third temperature T3 of the interior space of the heating chamber 50. For example, a constant DC current can be applied to the second heat source by controlling the switch on / off, and an intermittent DC current can be generated by controlling the DC current on / off.

[0095] In one embodiment of the present invention, the second heat source 55 maintains the third temperature T3 of the slow cooling space 50' of the heating chamber 50 at a temperature higher than room temperature, thereby providing an environment favorable for heating and maintaining the temperature (corresponding to the second temperature T2) of the internal space of the heating funnel 10 connected to the slow cooling space 50' at or above the melting point of the metal block. As a result, by operating the first and second heat sources 15, 55 simultaneously, it is possible to reduce the power consumption required to maintain the temperatures of the embedded block 40 and the space formed in the heating chamber 50, which are fluidly connected to each other, at a temperature at least higher than room temperature.

[0096] The first and second discharge nozzles 20a, 10a from which the first and second materials M1, M2 are discharged are positioned at a height that can be changed from the stage S by the raising and lowering operation of the stage S. The first and second discharge nozzles 20a, 10a are embedded in an embedding block 40 that together form an annealing space 50' in which the stage S is accommodated, and more specifically, are embedded in the embedding block 40 that defines the upper part of the annealing space 50', and can be positioned and fixed at a certain fixed position based on the heating chamber 50 depending on the relative assembly positions of the embedding block 40 and the heating chamber 50. In one embodiment of the present invention, the positions of the first and second discharge nozzles 20a, 10a are fixed at a predetermined position based on the heating chamber 50, and the first and second discharge nozzles 20a, 10a are maintained at a predetermined position within the heating chamber 50 through the lifting and two-dimensional translational movement of the connecting rod 100 or the guide block GB to which the connecting rod 100 is connected (e.g., the guide block GB of the third actuator A3, which reflects both the lifting and two-dimensional translational movement generated by the first to third actuators A1 to A3) power-connected through an opening 50'' penetrating the bottom wall 50b of the heating chamber 50. The stage S, power-connected to the actuator A through an opening 50'' penetrating the heating chamber 50, can be moved to the target discharge positions P1, P2 of the first and second materials M1, M2 for the first and second discharge nozzles 20a, 10a, which are maintained at a predetermined position within the heating chamber 50.

[0097] In various embodiments of the present invention, the first and second materials M1 and M2 discharged from the first and second discharge nozzles 20a and 10a are accumulated at first and second discharge positions P1 and P2 on the stage S through relative movement between the first and second discharge nozzles 20a and 10a and the stage S. For example, the first and second discharge positions P1 and P2 at which the first and second materials M1 and M2 are accumulated on the stage S may correspond to the outline position of the object and the filling position surrounded by the outline corresponding to the object itself, respectively. In one embodiment of the present invention, the first and second materials M1, M2 accumulated on the stage S from the first and second discharge nozzles 20a, 10a have different material phases from the first and second raw materials M1, M2, respectively, and are formed into the first and second materials M1, M2 through different pretreatment processes for the first and second raw materials, and such pretreatment processes may be performed by the respective extrusion devices 80 (mixing / extrusion pretreatment) and heating funnels 10 (heating pretreatment) that include the respective first and second discharge nozzles 20a, 10a or are connected to the first and second discharge nozzles 20a, 10a. In this case, in one embodiment of the present invention, taking into consideration the connectivity between the first and second discharge nozzles 20a, 10a and the extrusion device 80 and the heating funnel 10, the positions of the first and second discharge nozzles 20a, 10a are fixed, but the stage S on which the first and second materials M1, M2 are accumulated is moved from the first and second discharge nozzles 20a, 10a, and the stage S on which the first and second materials M1, M2 are discharged from the fixed first and second discharge nozzles 20a, 10a is moved, thereby controlling the discharge positions P1, P2 of the first and second materials M1, M2 on the stage S, and forming layers of the first and second materials M1, M2 at the outline position of the object to be formed and at the filling position surrounded by the outline of the object.

[0098] In various embodiments of the present invention, the first and second discharge nozzles 20a, 10a may be moved in a time sequence or simultaneously. For example, among the first and second discharge nozzles 20a, 10a embedded and fixed in position together in the embedding block 40, the first discharge nozzle 20a may be moved to first accumulate the outline of the object, and the movement of the first discharge nozzle 20a may be stopped and the second discharge nozzle 10a may be moved to subsequently fill the second material M2 into the filling space FS surrounded by the outline of the object formed from the first material M1, thereby forming the object. For example, in molding such a model, the first and second discharge nozzles 20a, 10a are alternately operated and stopped to form each layer of the model, and while the first discharge nozzle 20a is operating (while the second discharge nozzle 10a is stopped), the stage S is moved based on section data regarding the outline of the model formed from the first material M1 discharged from the first discharge nozzle 20a, and while the second discharge nozzle 10a is operating (while the first discharge nozzle 20a is stopped), the stage S can be moved based on section data regarding the model itself formed from the second material M2 discharged from the second discharge nozzle 10a or the filled space FS surrounded by the outline of the first material M1.

[0099] In one embodiment of the present invention, the first and second discharge nozzles 20a, 10a are moved simultaneously without any temporal relationship. For example, the first and second discharge nozzles 20a, 10a are embedded in a single embedding block 40 and bound to each other at a fixed interval. Due to the interval between the first and second discharge nozzles 20a, 10a, the discharge positions P1, P2 of the first and second materials M1, M2 discharged from the first and second discharge nozzles 20a, 10a may be spaced apart from each other at different positions on the stage S. For example, the discharge positions P1, P2 of the first and second materials M1, M2 on the stage S are formed with a gap corresponding to the gap g between the first and second discharge nozzles 20a, 10a which are embedded together in the embedding block 40 and bound to each other, and the gap g between the discharge positions P1, P2 of the first and second materials M1, M2 on the stage S can be filled by the metal flow of the second material M2 flowing from the second discharge position P2 of the second material M2 toward the first discharge position P1 of the first material M1.

[0100] In one embodiment of the present invention, the gap g between the first and second discharge nozzles 20a, 10a bound by the embedding block 40 may be formed narrow enough to satisfy the gap between the discharge positions P1, P2 of the first and second materials M1, M2 corresponding to the gap g between the first and second discharge nozzles 20a, 10a, based on the flow characteristics of the second material M2, such as the fluidity and flow rate of the second material M2.

[0101] In one embodiment of the present invention, the first and second discharge nozzles 20a, 10a for discharging the first and second materials M1, M2 having different material phases onto the stage S are formed with different inner diameters depending on the material phases of the first and second materials M1, M2, and the materials may be discharged onto the stage S from the first and second discharge nozzles 20a, 10a formed with different inner diameters. In one embodiment of the present invention, the first discharge nozzle 20a may discharge the first material M1 in a paste state or a slurry state, and the second discharge nozzle 10a may discharge the second material M2 in a liquid state. In this case, in one embodiment of the present invention, the inner diameter of the first discharge nozzle 20a, through which the first material M1 in a paste or slurry state, which is relatively less fluid, is formed relatively wider than the inner diameter of the second discharge nozzle 10a, through which the second material M2 in a liquid phase, which is relatively more fluid, is discharged. This allows the flow rates of the first and second materials M1 and M2 to be accumulated on the stage S in a balanced manner. For example, even if the volume of the second material M2, which fills the filling space FS surrounded by the outline of the object and forms the object itself, is relatively larger than the volume of the first material M1 that forms the outline of the object, the second material M2 in a liquid phase, which is highly fluid, can accumulate in a sufficient volume to form the object itself through the relatively narrow inner diameter of the second discharge nozzle 10a.

[0102] In one embodiment of the present invention, the flow rates (volume passing through a cross-sectional area per unit time) or discharge speeds of the first and second materials M1 and M2, which are different material phases, may be controlled in different ways. For example, the flow rate (volume passing through a cross-sectional area per unit time) or discharge speed of the first material M1 may be controlled by the rotation speed of the rotary screw 85 rotated within the transfer pipe 83 of the extrusion device 80. Separately, the flow rate (volume passing through a cross-sectional area per unit time) or discharge speed of the second material M2 may be controlled by the internal pressure of the heating funnel 10 filled with the second material M2 or the internal pressure acting on the liquid surface formed within the heating funnel 10 (the pressure of the gas RG filled between the sealing cover 1 covering the inlet and the liquid surface of the second material M2).

[0103] In one embodiment of the present invention, the second material M2 that forms the object to be molded is formed from a highly fluid liquid metal or metal flow, which makes it possible to form an object with a smooth and beautiful appearance compared to a comparative example 3D printing method in which the object itself is formed using the second material M2 in a paste or slurry state that includes metal powder and a vehicle and binder mixed with the metal powder.

[0104] In one embodiment of the present invention, the outline of the object and the object itself may be formed using first and second materials M1 and M2 of different material phases so as to have different fluidities. For example, the first material M1, which forms the outline of the object to form a fill space FS to be filled with the liquid second material M2 and restrict the flow of the liquid second material M2, may have relatively low fluidity so as not to collapse under its own weight and to have high shape stability. In contrast to the first material M1, the second material M2 may have relatively high fluidity so as to quickly fill the inside of the outline of the object formed from the first material M1. In this manner, in one embodiment of the present invention, a molded object is formed by filling the fill space FS surrounded by the outline formed in the first material M1 using a highly fluid liquid metal flow. Therefore, all or part of the molded object is formed at once through a single filling operation up to a height where the section data remains the same. The second material M2, which is in a paste or slurry state containing a binder with dispersed metal powder, is dropped in droplet form onto the stage S to form each layer of the second material M2 corresponding to a section of the molded object. The layers of the second material M2 are then stacked up to the entire height of the molded object, and then sintered by irradiating a laser. This may shorten the production time of the molded object compared to the comparative example of 3D printing, which forms the molded object by solidifying the molded object from the second material M2. For example, in the 3D printing of the comparative example described above, the second material M2 is dropped in droplet form onto the stage S to accumulate each layer of the second material M2 up to the entire height of the object. This means that the time required to manufacture the object is relatively longer than in the present invention, in which the second material M2 in liquid or metallic form is filled onto the stage S to fill the filled space FS surrounded by the outline of the object made of the first material M1. In particular, after the second material M2 is dropped in droplet form to form the height of the object on the stage S, a sintering process is performed using a separate laser beam. This means that, compared to the present invention, in which the object is completed by cooling the second material M2 after filling it, not to mention the need for separate laser equipment, this has the disadvantage of a longer manufacturing time.

[0105] In one embodiment of the present invention, even if the first material M1 that forms the outline of the object is in a paste or slurry state, in which ceramic particles are mixed with a matrix that serves as a vehicle for providing fluidity, and more specifically, compared to the second material M2 that forms the object itself by applying a liquid-phase metal flow with relatively high fluidity, the first material M1 that forms the outline of the object is applied in a paste or slurry state with somewhat lower fluidity and takes longer to be deposited on the stage S to form a unit volume (e.g., when comparing the dispensing times of the first and second materials M1 and M2 to form unit volumes of the first and second materials M1 and M2, the dispensing time of the first material M1 > the dispensing time of the second material M2), in one embodiment of the present invention, the second material M2 that forms the object itself fills the fill space FS surrounded by the outline of the object made of the first material M1, and therefore the total time required to manufacture the object is longer than the time required to form the first material M1, which has relatively lower fluidity. The total time required to manufacture the object is determined by or is not delayed by the dispensing time of the first material M1, which is not sufficient. Generally, the volume of the object itself is larger than the volume occupied by the outline of the object. Therefore, the total time required to manufacture the object is understood to be limited not by the dispensing time of the first material M1 to form the outline of the object, but by the dispensing time of the second material M2 to form the object itself, which is surrounded by the outline of the object. Therefore, regardless of the length relationship between the first and second dispensing times to form a unit volume of the first and second materials M1 and M2 (first dispensing time > second dispensing time), the dispensing time of the second material M2, which occupies a relatively larger volume, becomes the limiting factor that limits the total time required to manufacture the object as a whole. In one embodiment of the present invention, the dispensing time of the second material M2, which occupies a relatively larger volume, is used as the second material M2, which acts as a limiting factor for the total time required to manufacture the object, by using a liquid metal flow with relatively high fluidity as the second material M2, which acts as a limiting factor for the total time required to manufacture the object. This shortens the dispensing time of the second material M2, and thereby the total time required to manufacture the object. Unlike the present invention, the comparative example uses a paste or slurry material that is relatively less fluid than a liquid as the material for forming the object itself, which delays the dispensing time of the second material M2, which acts as a limiting factor for the total time required to produce the object, and as a result, the total time required to produce the object may be relatively delayed.

[0106] In one embodiment of the present invention, the first material M1 is extruded from an extruder 80, and different ceramic particles and a matrix for imparting fluidity to the ceramic particles, which are respectively introduced from first and second hoppers 81 and 82 connected to the transfer pipe 83 as raw materials (first raw materials) of the first material M1, are homogeneously mixed by the rotation of the rotary screw 85 in the transfer pipe 83, and the transfer speed of the first material M1 can be controlled by the rotation speed of the rotary screw 85. For example, in one embodiment of the present invention, the rotation speed of the rotary screw 85, which is rotated within the transfer pipe 83 of the extruder 80, is linked to the transfer speed of the first material M1 transferred along the connecting pipe 70, which is connected between the discharge port 80a of the extruder 80 and the fitting end 20b of the discharge unit 20, and may be linked to the flow rate (volume passing through a cross-sectional area per unit time) or discharge speed of the first discharge nozzle 20a, which forms the lower end of the discharge unit 20, through the discharge port 80a, to which one end of the connecting pipe 70 is connected, and the discharge unit 20, to which the other end of the connecting pipe 70 is connected. In one embodiment of the present invention, the first material M1 is formed in a paste or slurry state by mixing ceramic particles and a matrix, and the flow rate (volume passing through a cross-sectional area per unit time) or discharge speed of the first material M1 may be controlled through forced extrusion, for example, while controlling the mixing ratio of the matrix to impart fluidity to the ceramic particles.

[0107] In one embodiment of the present invention, the first material M1 may be formed in a paste or slurry state by mixing ceramic particles with a matrix such as a vehicle and a binder. For example, the binder ratio or binder components may be adjusted to control the viscosity of the first material M1, and the flow rate (volume passing through a cross-sectional area per unit time) or discharge speed of the first material M1 may be controlled through forced extrusion. For example, in one embodiment of the present invention, the first material M1 may be formed with a relatively high viscosity to increase the height stability of the first material M1 accumulated on the stage S, and the first material M1 may be discharged onto the stage S by forced extrusion so as to control the flow rate (volume passing through a cross-sectional area per unit time) or discharge speed of the first material M1 independently of the viscosity of the first material M1.

[0108] In one embodiment of the present invention, in the forced extrusion of the first material M1, the flow rate (volume passing through a cross-sectional area per unit time) or the discharge speed at the first discharge nozzle 20a connected to the discharge port 80a of the extrusion device 80 can be controlled by adjusting the rotation speed of the rotating screw 85 driven inside the transfer pipe 83 of the extrusion device 80. In contrast, in a comparative example in which the first material M1 in a paste or slurry state is dropped in the form of droplets, when the ratio or components of the binder contained in the first material M1 are controlled to increase the height stability of the first material M1 accumulated on the stage S, the flow rate (volume passing through a cross-sectional area per unit time) or extrusion speed of the first material M1 is delayed in conjunction with the viscosity of the first material M1, so it is necessary to compromise between the aspect of height stability of the first material M1 and the aspect of flow rate (volume passing through a cross-sectional area per unit time) or extrusion speed of the first material M1. For example, unlike one embodiment of the present invention, there may be a limit to shortening the takt time by increasing the flow rate (volume passing through a cross-sectional area per unit time) or extrusion speed of the first material M1 while increasing the height stability of the first material M1. For example, in one embodiment of the present invention, by increasing the height stability of the first material M1, the liquid metal flow fills the high filling space FS formed by the relatively high outline of the first material M1 at once, thereby shortening the time required to produce the object.In this case, the ejection time of the first material M1 itself is shortened, and by increasing the rotational speed of the rotating screw 85 driven within the transfer pipe 83 of the extrusion device 80, for example, the time required to form the outline of the first material M1 accumulated to a predetermined height is also shortened, thereby doubly shortening the ejection time.

[0109] In one embodiment of the present invention, the first material M1 forms the outline of the object so as to surround a filling space FS into which the liquid second material M2 is filled, and the second material M2 fills the filling space FS surrounded by the outline of the first material M1, and through subsequent cooling, the second material M2, not the first material M1, forms the object, which may mean that the object is completed through separation of the first material M1 after cooling of the second material M2.

[0110] In various embodiments of the present invention, the fact that the second material M2 formed by the liquid metal flow fills the filled space FS surrounded by the outline of the first material M1 does not limit the order of discharging the first and second materials M1 and M2. For example, it does not necessarily mean that the filled space FS surrounded by the outline of the first material M1 is filled with the second material M2 only after the outline of the object is formed by discharging the first material M1. For example, in various embodiments of the present invention, the discharging of the first and second materials M1 and M2 toward the stage S that provides the support base for the object is performed simultaneously without any time sequence. For example, the discharging of the first and second materials M1 and M2 toward the stage S may be performed simultaneously. Even when the first and second materials M1 and M2 are discharged at the same speed, due to the differential fluidity of the first material M1, M2, the first material M1 may spread widely across the plane of the stage S from the first discharge position P1 of the first material M1, or may not spread and be limited to the periphery of the first discharge position P1 of the first material M1. As a result, the outline of the object formed by the first material M1 has height stability and is clearly defined. For example, in one embodiment of the present invention, the first material M1 is formed in a paste or slurry state in which ceramic particles, a vehicle, and a matrix such as a binder for viscosity control are mixed, and has relatively low fluidity compared to the second material M2. As a result, the first material M1 may have height stability based on its low fluidity. For example, in one embodiment of the present invention, the fluidity of the first material M1 is controlled to ensure the stability of the height of the first material M1, and the height of the outline formed by the first material M1 is relatively high, and the fill space FS surrounded by the outline of the first material M1 is quickly filled with the second material M2 formed by the liquid metal flow, thereby shortening the time required to manufacture a 3D printing object according to one embodiment of the present invention. For example, in one embodiment of the present invention, until the two-dimensional section data of the 3D object have the same height, all or part of the object can be formed by discharging the first and second materials M1 and M2 in a single operation.

[0111] A 3D printing apparatus according to an embodiment of the present invention includes a control unit (not shown) for acquiring data related to the outer shape of a model and controlling the operation of the stage S. In this case, the control unit may move the stage S on which the first and second materials M1, M2 are accumulated at a relatively slow speed so that the first and second materials M1, M2 are accumulated from a single discharge (single layer) up to a height at which the section data of the model remains the same. For example, the control unit may move the stage S on which the first and second materials M1, M2 are accumulated at a relatively slow speed so that a relatively large volume or a relatively large flow rate of the first and second materials M1, M2 are accumulated on the stage S at the first and second discharge positions P1, P2 where the first and second materials M1, M2 are accumulated to form the height of the model.

[0112] In one embodiment of the present invention, first and second raw materials M1, M2 having different shapes from the first and second raw materials M1, M2 discharged onto the stage S are input into the 3D printing device, and a separate process is performed to process the first and second raw materials M1, M2 from the different first and second raw materials. Therefore, in consideration of the connection with the heating funnel 10 and the extrusion device 80 that perform such pre-treatment processes, instead of moving the first and second discharge nozzles 20a, 10a while maintaining a fixed position, the first and second discharge positions P1, P2 can be controlled while moving the stage S containing the first and second materials M1, M2 from the first and second discharge nozzles 20a, 10a, to form the outline of the object and the shape of the object surrounded by the outline of the object.

[0113] A 3D printing apparatus according to one embodiment of the present invention includes a first actuator A1 for driving a stage S up and down along a height direction Z1, and second and third actuators A2 and A3 for driving the stage S in translation in second and third directions Z2 and Z3 along a two-dimensional plane, and these first to third actuators A1 to A3 control the three-axis position of the stage S independently of each other, and can be controlled, for example, to independently track target positions of the stage S in the first to third directions Z1 to Z3. In one embodiment of the present invention, the second actuator A2 is mounted on the guide block GB of the first actuator A1 and follows the position in the second direction Z2 targeted by the second actuator A2 based on the position in the first direction Z1 targeted by the first actuator A1, and the third actuator A3 is mounted on the guide block GB of the second actuator A2 and follows the position in the third direction Z3 targeted by the first and second actuators A1 and A2 based on the positions in the first and second directions Z1 and Z2 targeted by the first and second actuators A1 and A2. As a result, the stage S connected to the guide block GB of the third actuator A3 via the connecting rod 100 mounted on the guide block GB of the third actuator A3 can three-dimensionally follow the positions in the first to third directions Z1 to Z3 targeted by the first to third actuators A1 to A3.

[0114] In one embodiment of the present invention, the embedding block 40, the heating chamber 50, and the actuator A can be aligned with one another via assembly guide rods R. For example, in one embodiment of the present invention, the embedding block 40 and the heating chamber 50 are substantially hexahedral in shape, and the assembly guide rods R are set to align the embedding block 40 and the heating chamber 50 through a group of assembly guide rods R extending across the four corners of the embedding block 40 and the heating chamber 50. For example, the embedding block 40, which defines the top of the annealing space 50′ in which the stage S is housed, and the four side walls of the heating chamber 50, which define the sides of the annealing space 50′, can be aligned with one another and form an airtight sealed connection with one another. Furthermore, in one embodiment of the present invention, the group of assembly guide rods R aligns the positions of the actuator A arranged outside the heating chamber 50 and the heating chamber 50, and as a result, the group of assembly guide rods R aligns the positions of the actuator A arranged outside the heating chamber 50, the heating chamber 50, the embedding block 40 assembled with the heating chamber 50, and the first and second discharge nozzles 20a, 10a embedded in the embedding block 40, thereby precisely controlling the discharge positions P1, P2 of the first and second materials M1, M2 discharged onto the stage S from the first and second discharge nozzles 20a, 10a.

[0115] In one embodiment of the present invention, the smallest dimension of the target object may be at least 0.05 mm, 0.1 mm, 0.2 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, or any value therebetween. In one embodiment of the present invention, the longest dimension of the target object may not exceed 100 mm, 50 mm, 10 m, 5 m, 1000 mm, 900 mm, 800 mm, 700 mm, 600 mm, 500 mm, 400 mm, 300 mm, 250 mm, or any value therebetween. In one embodiment of the present invention, the target object may be a functional object, such as a medical device, an orthopedic medical device, or a part of an orthopedic medical device. In various embodiments of the present invention, the target object may be a figurine.

[0116] In one embodiment of the present invention, the 3D printing device comprises: a stage that provides a support base for the object to be modeled; the first and second discharge nozzles on the stage include a first discharge nozzle that discharges a first material in a paste state or a slurry state that forms the outline of the object to be modeled, and a second discharge nozzle that discharges a second material in a liquid state that fills a filling space surrounded by the first material; an extrusion device connected to the first discharge nozzle, extruding a first material in a paste or slurry state toward the first discharge nozzle to extrude a first material including ceramic particles and a matrix in which the ceramic particles are dispersed; a heating funnel connected to the second discharge nozzle, the heating funnel receiving the metal block, melting the metal block, and supplying a second material in a liquid state, the second material being a molten metal; and a heating chamber for accommodating the stage, the heating chamber providing a space for slow cooling of the object formed by the first and second materials accumulated on the stage.

[0117] A 3D printing method according to one embodiment of the present invention includes: extruding a first material including ceramic particles and a matrix in which the ceramic particles are dispersed as a first material in a paste or slurry state from an extrusion device toward a first discharge nozzle; discharging a first material through a first discharge nozzle to form an outline of a target object; receiving a metal block through a heating funnel; melting the metal block to form a molten metal block flow, the molten metal second material being directed toward a second discharge nozzle; discharging a second material through a second discharge nozzle so that the second material fills a filling space surrounding an outline of the object formed from the first material; and forming a model on the stage by repeatedly discharging the first and second materials layer by layer.

[0118] The present invention has been described with reference to the embodiments shown in the accompanying drawings, but this is for illustrative purposes only, and those skilled in the art to which the present invention pertains will recognize that various modifications and equivalent alternative embodiments are possible therefrom. [Industrial Applicability]

[0119] The present invention can be applied to a 3D printing apparatus for forming a model having a specific shape.

Claims

1. a stage that provides a support base for the object to be modeled; first and second discharge nozzles disposed on the stage so as to respectively discharge a first material in a paste or slurry state that forms the contour of the object, and a second material in a liquid phase that fills a filling space surrounded by the contour of the object made of the first material; an extrusion device connected to the first discharge nozzle for extruding a first material toward the first discharge nozzle so as to discharge a first material in a paste or slurry state in which ceramic particles and a matrix in which the ceramic particles are dispersed are mixed; a heating funnel connected to the second discharge nozzle, the heating funnel receiving the metal block as an input and melting the metal block so as to discharge a second material in the form of a molten liquid metal flow through the second discharge nozzle; a heating chamber for accommodating the stage and providing a space for slow cooling of the first and second materials accumulated on the stage from the first and second discharge nozzles.

2. 2. The 3D printing apparatus of claim 1, wherein an inner diameter of the second discharge nozzle is smaller than the longest dimension of a metal block that is inserted through an inlet at an upper end of a heating funnel connected to the lower second discharge nozzle.

3. The 3D printing apparatus according to claim 1 , wherein a first heat source for melting the metal block inserted into the heating funnel is wound around the outer circumferential surface of the heating funnel.

4. 4. The 3D printing apparatus of claim 3, wherein the first heat source is disposed between a heating funnel having a second discharge nozzle formed at a lower end facing the stage and a discharge unit having a first discharge nozzle formed at a lower end facing the stage.

5. The 3D printing apparatus of claim 1 , further comprising an embedding block for embedding both the first and second discharge nozzles.

6. 2. The 3D printing apparatus of claim 1, wherein the third temperature of the slow cooling space of the heating chamber satisfies a relationship of second temperature > third temperature > first temperature between a second temperature of a heating funnel having a second discharge nozzle formed at a lower end facing the stage and a first temperature of a discharge unit having a first discharge nozzle formed at a lower end facing the stage.

7. a first heat source wound around the outer circumferential surface of the heating funnel for melting a metal block inserted into the heating funnel; 2. The 3D printing apparatus of claim 1, further comprising: a second heat source formed within the heating chamber for controlling a cooling rate of the first and second materials accumulated on the stage from the first and second discharge nozzles.

8. During the takt time required to create one object, 8. The 3D printing apparatus of claim 7, wherein a first operating time from when the first heat source starts to operate until it stops operating and a second operating time from when the second heat source starts to operate until it stops operating have a magnitude relationship of first operating time < second operating time.

9. a flow rate of the first material discharged onto the stage from the first discharge nozzle is controlled by a rotation speed of a rotating screw driven inside a transfer pipe of the extrusion device; 2. The 3D printing apparatus of claim 1, wherein a flow rate of the second material discharged onto the stage from the second discharge nozzle is controlled by a pressure of a gas filled above a liquid surface of the second material in the metal flow inside the heating funnel.

Images