Recoater device and 3D printer including same

Abstract

The present invention relates to a recoater device capable of applying a powder material onto a molding stage in a 3D printer and a 3D printer including the same. The device comprises a recoater body installed to be slidably movable along the longitudinal direction of the molding stage, a powder chamber formed to be extended lengthwise along the extension direction of the recoater body inside the recoater body and having a coating slit formed on the lower side for applying the powder material downward, and a pair of feeding shafts formed to be extended lengthwise in a cylindrical shape along the extension direction of the recoater body, and a feeding roller module formed to be rotatably installed at a position corresponding to the coating slit on the lower side of the powder chamber inside the recoater body and applying the powder material through the gap space between the pair of feeding shafts by rotation. The pair of feeding shafts may be arranged to be inclined at a predetermined angle with respect to the sliding direction of the recoater body.

Description

Technology Field

[0001] The present invention relates to a recoater device and a 3D printer including the same, and more specifically, to a recoater device capable of applying a powder material onto a molding stage in a 3D printer and a 3D printer including the same. Background Technology

[0002] 3D printing technology refers to a manufacturing technology that produces objects by printing them in a three-dimensional space based on a three-dimensional blueprint. Although it was initially limited to plastic materials and used for restricted purposes, its scope has expanded to include nylon and metals, and it is now being applied across all industrial sectors to the extent that it can print everything from mobile phone cases to automotive parts.

[0003] Generally, most industrial metal 3D printers follow the Selective Laser Sintering (SLS) method, which creates products by applying metal powder and melting only the desired areas with a laser. Additionally, the Binder-Jet method, which creates products by applying metal or plastic powder onto a build box stage and spraying adhesive onto desired areas, has recently been gaining prominence. The Binder-Jet method has the advantage of being able to print products at a faster speed in a single step and has fewer size constraints compared to the SLS method.

[0004] As such, a 3D printer based on powder material includes a recoater device that applies powder material onto a molding stage to form a powder layer on the molding stage. However, this conventional recoater device had a problem in which powder material leaked from the recoater device when the straightness tolerance of the feeder roller, which is rotatably installed in the coating slit where the powder material is applied and controls the application of the powder material, was large. In addition, when the gap space of the feeder roller installed in the coating slit was reduced to prevent powder material leakage due to the straightness tolerance of the feeder roller in the recoater device, an excessive load was placed on the motor driving the feeder roller, causing the motor to stop operating. The problem to be solved

[0005] The present invention aims to solve various problems, including the problems mentioned above, by providing a recoater device capable of uniformly applying a powder material in a precise quantity at a high density on a molding stage without leakage of the powder material, and a 3D printer including the same. However, these problems are exemplary and the scope of the present invention is not limited by them. means of solving the problem

[0006] According to one embodiment of the present invention, a recoater device is provided. The recoater device comprises: a recoater body formed to extend long along the width direction of a molding stage on which a powder material is applied so as to form a three-dimensional object by three-dimensional printing, and installed to slide along the length direction of the molding stage on the upper side of the molding stage; and a powder chamber formed to extend long along the extension direction of the recoater body inside the recoater body, and having a coating slit formed on the lower side to apply the powder material downward, so as to form a storage space for storing the powder material to be applied to the molding stage. The feeding roller module is formed by a pair of feeding shafts that are formed to be extended in a cylindrical shape along the extension direction of the recoater body, and is rotatably installed at a position corresponding to the coating slit below the powder chamber inside the recoater body, and applies the powder material through the gap space between the pair of feeding shafts by rotation; wherein the pair of feeding shafts may be arranged at an inclined angle with respect to the sliding movement direction of the recoater body.

[0007] According to one embodiment of the present invention, the feeding roller module may include: a first feeding shaft rotatably installed at a position corresponding to the coating slit; and a second feeding shaft rotatably installed at a position corresponding to the coating slit so as to be arranged parallel to the first feeding shaft to form the gap space between the first feeding shaft and the second feeding shaft, and positioned at an upwardly inclined position at a predetermined angle of inclination relative to the first feeding shaft.

[0008] According to one embodiment of the present invention, the predetermined inclination angle between the first feeding shaft and the second feeding shaft may be formed as an inclination angle between 60 and 80 degrees.

[0009] According to one embodiment of the present invention, the feeding roller module may further include: a first feeding drive unit installed in a first motor space formed on one side of the powder chamber inside the recoater body and connected to the first feeding shaft by a belt and pulley combination to rotate the first feeding shaft; and a second feeding drive unit installed in the first motor space and connected to the second feeding shaft by a belt and pulley combination to rotate the second feeding shaft.

[0010] According to one embodiment of the present invention, the first feeding drive unit is installed on the side of one end of the first motor space with respect to the extension direction of the recoater body and is connected to the first feeding shaft by a belt and pulley combination at one end of the recoater body, and the second feeding drive unit is installed on the side of the other end of the first motor space with respect to the extension direction of the recoater body and can be connected to the second feeding shaft by a belt and pulley combination at the other end of the recoater body.

[0011] According to one embodiment of the present invention, the feeding roller module may further include: a first feeding belt tensioner installed at one end of the recoater body to press a belt connecting the first feeding drive unit and the first feeding shaft; and a second feeding belt tensioner installed at the other end of the recoater body to press a belt connecting the second feeding drive unit and the second feeding shaft.

[0012] According to one embodiment of the present invention, a stirring roller may be further included, which is formed to extend in a cylindrical or polygonal column shape along the extension direction of the recoater body, is rotatably installed in the storage space of the powder chamber, and stirs the powder material stored in the storage space by rotation.

[0013] According to one embodiment of the present invention, the stirring roller may be formed such that a plurality of protrusions formed to protrude from the outer surface are arranged at predetermined intervals along the extension direction and radial direction of the stirring roller.

[0014] According to one embodiment of the present invention, the protrusion may be screw-coupled to a screw groove formed on the outer surface of the stirring roller, thereby being replaceably coupled to the stirring roller.

[0015] According to one embodiment of the present invention, the invention may further include a packing roller module formed by a pair of packing shafts extending in a cylindrical shape along the extension direction of the recoater body, rotatably installed on one side of the feeding roller module inside the recoater body, wherein at least a portion of the lower end protrudes from the lower end of the recoater body, and which packs the powder material applied to the molding stage by pressing and flattening it through rotation.

[0016] According to one embodiment of the present invention, the feeding roller module is driven to rotate so as to apply the powder material onto the molding stage when the recoater body moves forward on the upper side of the molding stage, and the packing roller module is driven to rotate so as to pack the powder material applied onto the molding stage when the recoater body, having completed moving forward on the upper side of the molding stage, moves backward.

[0017] According to one embodiment of the present invention, the packing roller module may include: a first packing shaft rotatably installed on one side of the feeding roller module; and a second packing shaft rotatably installed parallel to the first packing shaft, and positioned horizontally with respect to the sliding movement direction of the recoater body.

[0018] According to one embodiment of the present invention, the packing roller module may further include: a first packing drive unit installed in a second motor space formed on one side of a first motor space inside the recoater body and connected to the first packing shaft by a belt and pulley combination to rotate the first packing shaft; and a second packing drive unit installed in the second motor space and connected to the second packing shaft by a belt and pulley combination to rotate the second packing shaft.

[0019] According to one embodiment of the present invention, the first packing drive unit is installed on the side of one end of the second motor space with respect to the extension direction of the recoater body and is connected to the first packing shaft by a belt and pulley combination at one end of the recoater body, and the second packing drive unit is installed on the side of the other end of the second motor space with respect to the extension direction of the recoater body and can be connected to the second packing shaft by a belt and pulley combination at the other end of the recoater body.

[0020] According to one embodiment of the present invention, the packing roller module may further include: a first packing belt tensioner installed at one end of the recoater body to press a belt connecting the first packing drive unit and the first packing shaft; and a second packing belt tensioner installed at the other end of the recoater body to press a belt connecting the second packing drive unit and the second packing shaft.

[0021] According to one embodiment of the present invention, the first packing drive unit can rotate the first packing shaft, which is located relatively forward when the recoaster body moves backward, in the reverse direction relative to the direction of backward movement, and the second packing drive unit can rotate the second packing shaft, which is located relatively rearward when the recoaster body moves backward, in the forward direction relative to the direction of backward movement.

[0022] According to one embodiment of the present invention, the second packing drive unit can rotate the second packing shaft such that the linear velocity of the second packing shaft, which rotates in the forward direction, is equal to the reverse movement speed of the recoter body.

[0023] According to one embodiment of the present invention, the second packing shaft may be formed as a shaft having a larger diameter than the first packing shaft.

[0024] According to one embodiment of the present invention, the packing roller module may further include a blade unit formed to extend long in a blade shape along the extension direction of the recoater body, installed so that its end contacts the second packing shaft inside the recoater body, and removing the powder material attached to the second packing shaft when the second packing shaft is rotated.

[0025] According to another embodiment of the present invention, a 3D printer is provided. The 3D printer comprises: a molding box module including a molding stage formed in a box shape with an open top so as to receive a powder material and form a molding space in which a 3D object can be molded, and which is movably mounted inside so as to form a 3D object and is formed by stacking a plurality of layers on its upper surface; a powder coating module including a recoater device installed movably above the molding box module to form a powder layer on the molding stage; and a printing module including a printing head installed movably above the molding box module to spray a liquid material containing a binder onto the powder layer formed on the molding stage; wherein the recoater device comprises a recoater body formed to extend long along the width direction of the molding stage and installed to slide movably along the length direction of the molding stage above the molding stage. A powder chamber formed to extend long along the extension direction of the recoater body inside the recoater body and having a coating slit formed on the lower side for applying the powder material downward, so as to form a storage space for storing the powder material to be applied to the molding stage; and a feeding roller module formed by a pair of feeding shafts extending long in a cylindrical shape along the extension direction of the recoater body, rotatably installed at a position corresponding to the coating slit on the lower side of the powder chamber inside the recoater body, and applying the powder material through the gap space between the pair of shafts by rotation; wherein the pair of feeding shafts may be arranged at an inclined angle with respect to the sliding movement direction of the recoater body. Effects of the invention

[0026] According to one embodiment of the present invention as described above, a pair of feeding shafts of a feeding roller module, which is rotatably installed in a coating slit where a powder material is applied in a recoater device and controls the amount of powder material applied, are positioned at an optimized predetermined angle of inclination derived from experiments in advance, thereby preventing the powder material from leaking through the gap space between the pair of feeding shafts even when a tolerance in the straightness of the pair of feeding shafts occurs, and preventing an excessive load from occurring on the feeding drive unit that drives each of the pair of feeding shafts due to an excessively narrow gap space.

[0027] In addition, a packing roller module is installed on one side of the feeding roller module to pressurize and flatten the powder material applied thereto for packing. During the process of the recoater body moving forward to apply the powder material and moving backward, the powder material applied on the molding stage can be packed into a high-density powder layer with a uniform thickness.

[0028] In addition, by implementing a structure in which a pair of feeding shafts of the aforementioned feeding roller module, a pair of packing shafts of the packing roller module, and driving units and power transmission members that individually drive these shafts are integrated within the recoater body, the shafts and power transmission members are prevented from being contaminated by the external environment, thereby increasing the maintenance cycle and enabling more precise operation.

[0029] In this way, by applying a precise amount of powder material onto the molding stage without leakage of the powder material and packing the applied powder material into a flattened, high-density powder layer, it is possible to realize a recoater device and a 3D printer including the same that can improve the precision and strength of a 3D object molded by 3D printing. Of course, the scope of the present invention is not limited by these effects. Brief explanation of the drawing

[0030] FIG. 1 is a perspective view schematically showing the overall appearance of a 3D printer according to one embodiment of the present invention. Figures 2 and 3 are cross-sectional views schematically showing the front and top views of the 3D printer of Figure 1. FIGS. 4 and FIGS. 5 are a perspective view and a cross-sectional view schematically showing the overall appearance and plan of the recoater device of the powder coating module included in the 3D printer of FIG. 1. FIGS. 6 to 9 are cross-sectional views schematically showing the internal structure of the recoater device of FIGS. 4 and 5. FIG. 10 is a cross-sectional view schematically showing the feeding roller of the recoater device of FIG. 9. Specific details for implementing the invention

[0031] Hereinafter, several preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

[0032] The embodiments of the present invention are provided to more fully explain the invention to those skilled in the art, and the following embodiments may be modified in various different forms, and the scope of the invention is not limited to the following embodiments. Rather, these embodiments are provided to make the disclosure more faithful and complete and to fully convey the spirit of the invention to those skilled in the art. In addition, the thickness or size of each layer in the drawings is exaggerated for convenience and clarity of explanation.

[0033] Hereinafter, embodiments of the present invention are described with reference to drawings that schematically illustrate ideal embodiments of the present invention. In the drawings, variations of the illustrated shapes may be expected, for example, depending on manufacturing techniques and / or tolerances. Accordingly, embodiments of the inventive concept should not be interpreted as being limited to specific shapes of the areas illustrated herein, but should include, for example, variations in shape resulting from manufacturing.

[0034] FIG. 1 is a perspective view schematically showing the overall appearance of a 3D printer (1) according to one embodiment of the present invention, and FIG. 2 and FIG. 3 are cross-sectional views schematically showing the front and top views of the 3D printer (1) of FIG. 1. FIG. 4 and FIG. 5 are a perspective view and a cross-sectional view schematically showing the overall appearance and top view of a recoater device (3100) of a powder coating module (3000) included in the 3D printer (1) of FIG. 1, FIG. 6 to FIG. 9 are cross-sectional views schematically showing the internal structure of the recoater device (3100) of FIG. 4 and FIG. 5, and FIG. 10 is a cross-sectional view schematically showing the feeding roller (400) of the recoater device (3100) of FIG. 9.

[0035] First, as illustrated in FIGS. 1 to 3, a 3D printer (1) according to one embodiment of the present invention may largely include a main body (1000), a molding box module (2000), a powder coating module (3000), a printing module (4000), and a cleaning station module (5000).

[0036] As illustrated in FIGS. 1 to 3, the main body (1000) may be a type of frame structure in which a molding box module (2000) is housed inside, and a powder coating module (3000), a printing module (4000), and a cleaning station module (5000) are installed and supported on the upper side.

[0037] For example, this main body (1000) may be a frame structure formed by welding or connecting together an integral injection molded structure, a casting, or various shaped plates, wires, pipes, vertical members, horizontal members, and inclined members.

[0038] As illustrated in FIGS. 1 to 3, the molding box module (2000) is formed in a box shape with an open top so that a molding space can be formed in which a powder material is received and a three-dimensional mold can be formed, and may include a molding stage (2100) which is housed in the main body (1000) and is configured to be able to move up and down in the height direction (Z-axis direction) so that a three-dimensional mold can be formed by stacking a plurality of layers.

[0039] At this time, the main body (1000) may be formed so that the upper part of the portion in which the molding box module (2000) is housed is open, so that the molding stage (2100) of the molding box module (2000) can be exposed to the powder coating module (3000) and printing module (4000) installed on the upper side.

[0040] As illustrated in FIGS. 1 to 3, the printing module (4000) is installed to be slidably movable on the upper side of the molding box module (2000) and can spray a liquid material containing a binder onto a powder layer formed on the molding stage (2100).

[0041] For example, the printing module (4000) may include a printing head (4100) having a nozzle formed on its lower side so as to spray a liquid material containing a binder onto a powder layer formed on a molding stage (2100), and a printing head driving device (4200) that slides the printing head (4100) in at least one of the length direction (X-axis direction), width direction (Y-axis direction), and height direction (Z-axis direction) of the main body (1000) from the upper side of the main body (1000) so as to move the printing head (4100) to the upper side of the molding stage (2100) or to move toward the cleaning station module (5000) when waiting for the process.

[0042] As illustrated in FIGS. 1 to 3, the cleaning station module (5000) is installed on one side of the molding box module (2000) above the main body (1000) and can clean the nozzle of the printing head (4100) while waiting for the process and pack the cleaned nozzle so that it is not exposed to the atmosphere.

[0043] For example, the cleaning station module (5000) is equipped with a wiper blade that can be selectively immersed in a cleaning solution, and when the printing head (4100) moves upward, the wiper blade rotates to contact the nozzle of the printing head (4100) to wipe and clean the nozzle of the printing head (4100); a spraying stage (5200) in which the printing head (4100) purges a liquid material to prevent clogging of the nozzle of the printing head (4100); and a porous elastomer that absorbs a cleaning solution to pack the nozzle of the printing head (4100) so as to prevent clogging due to drying of the nozzle of the printing head (4100) while the printing head (4100) is waiting for the process, thereby printing It may include an air stage (5300) that protects the nozzle of the head (4100) from the external environment.

[0044] Here, the cleaning station module (5000) is shown as being arranged in a line in the order of the spraying stage (5200), the cleaning stage (5100), and the waiting stage (5300) based on the longitudinal direction (X-axis direction) of the body (1000), but is not necessarily limited to FIG. 1, and the arrangement order of the spraying stage (5200), the cleaning stage (5100), and the waiting stage (5300) can be configured in many different ways according to the user's needs.

[0045] As illustrated in FIGS. 1 to 3, the powder coating module (3000) is movably installed on the upper side of the molding box module (2000) and can apply a powder material on the molding stage (2100) so as to form a powder layer of a predetermined thickness on the molding stage (2100).

[0046] For example, the powder coating module (3000) may include a recoater device (3100) installed to be slidably movable in the longitudinal direction (X-axis direction) of the main body (1000) on the upper side of the main body (1000) so as to be positioned within the sliding range of the recoater device (3100) on the upper side of the main body (1000) so as to be able to apply a powder material on the molding stage (2100) during the process of slidingly moving the upper side of the molding box module (2000) housed in the main body (1000), and a hopper part (3200) installed on the other side of the molding stage (2100) so as to be positioned within the sliding range of the recoater device (3100) on the upper side of the main body (1000) so as to be able to supply a powder material to the recoater device (3100).

[0047] Below, the recoater device (3100) included in the powder coating module (3000) described above will be explained in detail.

[0048] As illustrated in FIGS. 4 to 6, the recoater device (3100) may largely include a recoater body (100), a powder chamber (200), a feeding roller module (300), a stirring roller (400), and a packing roller module (500).

[0049] As illustrated in FIGS. 4 to 6, the recoater body (100) is formed to be extended longer than the width of the molding stage (2100) along the width direction (Y-axis direction) of the molding stage (2100), where a powder material is applied to form a powder layer so that a three-dimensional object can be molded by three-dimensional printing, and can be installed to be slidably moved linearly along the length direction (X-axis direction) of the molding stage (2100).

[0050] For example, the recoater body (100) may be a structure such as a case that is formed to extend in a rectangular shape along the width direction (Y-axis direction) of the molding stage (2100) so that the powder chamber (200) to be described later, the feeding roller module (300), the stirring roller (400), and the packing roller module (500) can be housed inside.

[0051] The recoater body (100) can be installed to be able to slide linearly along the length direction (X-axis direction) of the molding stage (2100) on the upper side of the molding stage (2100) by having a pair of flange portions (110) formed to protrude from both ends of the body (100) in the extension direction (Y-axis direction) of the body (100) seated on a pair of rail portions (see R in FIG. 3) formed to extend long along the length direction (X-axis direction) of the molding stage (2100) from both sides in the width direction (Y-axis direction) of the molding stage (2100).

[0052] More specifically, the recoater body (100) can be installed to move forward along a pair of rail sections (R) away from the hopper section (see 3200 in FIG. 3) on the upper side of the molding stage (2100), or move backward along the upper side of the molding stage (2100) towards the hopper section (3200), so as to be able to move linearly back and forth sliding on the upper side of the molding stage (2100).

[0053] As illustrated in FIGS. 4 to 6, the powder chamber (200) is formed to extend long along the extension direction (Y-axis direction) of the recoater body (100) inside the recoater body (100) so as to form a storage space (A) in which a powder material to be applied to the molding stage (2100) is stored, and a coating slit (210) can be formed on the lower side to apply the powder material downward.

[0054] For example, the powder chamber (200) is a place where powder material is temporarily stored before being applied onto the molding stage (2100). When the recoater body (100) moves to a position corresponding to the hopper section (see 3200 in FIG. 3), the upper side is open to receive powder material falling from the hopper section (3200), and a coating slit (210) may be formed on the lower side so that powder material temporarily stored in the internal storage space (A) can be applied according to the rotational drive of the feeding roller module (300) to be described later.

[0055] The powder chamber (200) is formed such that, with respect to the height direction (Z-axis direction), the width in the sliding movement direction (X-axis direction) of the recoater body (100) gradually narrows as it moves from top to bottom, and can be formed in a hopper shape overall with respect to the cross-section (XZ plane).

[0056] Accordingly, the upper portion into which powder material falls and flows from the hopper portion (3200) can be formed with a relatively large width (based on the X-axis direction), and the lower portion into which the coating slit (210) is formed can be formed with a relatively narrow width (based on the X-axis direction).

[0057] As illustrated in FIGS. 4 to 6, the feeding roller module (300) is formed with a pair of feeding shafts (310, 320) that are formed to extend in a cylindrical shape along the extension direction (Y-axis direction) of the recoater body (100), and is rotatably installed at a position corresponding to the coating slit (210) on the lower side of the powder chamber (200) inside the recoater body (100), and can apply powder material through the gap space (G) between the pair of feeding shafts (310, 320) by rotation.

[0058] At this time, a pair of feeding shafts (310, 320) of the feeding roller module (300) may be arranged at a predetermined angle of inclination (a) with respect to the sliding movement direction (X-axis direction) of the recoater body (100).

[0059] For example, the feeding doler module (300) may include a first feeding shaft (310) which is formed to be extended in a cylindrical shape along the extension direction (Y-axis direction) of the recoater body (100) and is rotatably installed at a position corresponding to the coating slit (210), and a second feeding shaft (320) which is formed to be extended in a cylindrical shape parallel to the first feeding shaft (310) along the extension direction (Y-axis direction) of the recoater body (100), is rotatably installed at a position corresponding to the coating slit (210) so as to be arranged parallel to the first feeding shaft (310) to form a gap space (G) between it and the first feeding shaft (310), and is positioned at an upwardly inclined position at a predetermined inclination angle (a) relative to the first feeding shaft (310).

[0060] More specifically, the feeding roller module (300) may be positioned such that a virtual line segment (b) connecting the rotation axis of the first feeding shaft (310) and the rotation axis of the second feeding shaft (320) is inclined at a predetermined angle of inclination (a) with respect to the sliding movement direction (X-axis direction) of the recoater body (100). At this time, the first feeding shaft (310) may be installed so as to be positioned lower in the direction of inclination relative to the second feeding shaft (320), and the second feeding shaft (320) may be installed so as to be positioned higher in the direction of inclination relative to the first feeding shaft (310).

[0061] Here, the predetermined angle of inclination (a) between the first feeding shaft (310) and the second feeding shaft (320) is an angle of inclination that ensures that the gap space (G) between the first feeding shaft (310) and the second feeding shaft (320) is secured to the extent that no leakage of powder material occurs through the gap space (G) between the first feeding shaft (310) and the second feeding shaft (320) and no load occurs when the first feeding shaft (310) and the second feeding shaft (320) rotate, even if the straightness of the first feeding shaft (310) and the second feeding shaft (320) is not constant. As shown in FIG. 11, the inventors determined through repeated experiments that an angle of inclination between 60 and 80 degrees is desirable, and most preferably, it was confirmed that an angle of inclination of 70 degrees, which does not result in overloading, is the best.

[0062] Additionally, the feeding roller module (300) can have its rotational drive individually controlled by a feeding drive unit (330, 340) that is built together in the recoater body (100).

[0063] For example, as illustrated in FIGS. 6 to 9, the feeding roller module (300) may further include a first feeding drive unit (330) that is installed in a first motor space (MA1) formed on one side of a powder chamber (200) inside a recoater body (100) and is connected to a first feeding shaft (310) by a combination of a belt (B1) and a pulley (P1-1, P1-2) to rotate the first feeding shaft (310), and a second feeding drive unit (340) that is installed symmetrically to the first feeding drive unit (330) in the first motor space (MA1) and is connected to a second feeding shaft (320) by a combination of a belt (B2) and a pulley (P2-1, P2-2) to rotate the second feeding shaft (320).

[0064] At this time, each feeding drive unit (330, 340) can be connected to the feeding shafts (310, 320) at different ends based on the extension direction (Y-axis direction) of the recoater body (100) so as to reduce the installation area within the recoater body (100) and so that the power transmission members (B1, B2, P1-1, P2-1, P2-1, P2-2) installed for individual power transmission with each feeding shaft (310, 320) do not interfere with each other.

[0065] For example, as shown in FIGS. 7 and 9, the first feeding drive unit (330) is installed at one end of the first motor space (MA1) (right end in FIG. 9) with respect to the extension direction (Y-axis direction) of the recoater body (100), and can be connected to the first feeding shaft (310) by a combination of a belt (B1) and pulleys (P1-1, P1-2) at one end of the recoater body (100).

[0066] Additionally, as shown in FIGS. 8 and 9, the second feeding drive unit (340) is installed at the other end of the first motor space (MA1) (left end in FIG. 9) with respect to the extension direction (Y-axis direction) of the recoater body (100), and can be connected to the second feeding shaft (320) by a combination of a belt (B2) and pulleys (P2-1, P2-2) at the other end of the recoater body (100).

[0067] Here, the power transmission members (B1, B2, P1-1, P1-2, P2-1, P2-2) that individually transmit power between the feeding drive units (330, 340) and the feeding shafts (310, 320) are exemplified as a belt and pulley combination, but are not necessarily limited thereto; any type of power transmission member capable of individually transmitting power between the feeding drive units (330, 340) and the feeding shafts (310, 320), such as a chain and sprocket combination or a gear combination, may be applied.

[0068] In this way, the feeding roller module (300) can rotate only the first feeding shaft (310) located relatively lower or the second feeding shaft (320) located relatively upper by means of the first feeding drive unit (330) and the second feeding drive unit (340) which are embedded together inside the recoater body (100) so as to individually rotate the first feeding shaft (310) and the second feeding shaft (320), or rotate the first feeding shaft (310) and the second feeding shaft (320) together in twin mode when a larger amount of powder material is required.

[0069] Additionally, the feeding roller module (300) may further include a first feeding belt tensioner (350) installed at one end of the recoater body (100) to press the belt (B1) connecting the first feeding drive unit (330) and the first feeding shaft (310) to maintain the tension of the belt (B1), and a second feeding belt tensioner (360) installed at the other end of the recoater body (100) to press the belt (B2) connecting the second feeding drive unit (340) and the second feeding shaft (320) to maintain the tension of the belt (B2).

[0070] As illustrated in FIGS. 4 to 6, the packing roller module (500) is formed with a pair of packing shafts (510, 520) that are formed to extend in a cylindrical shape along the extension direction (Y-axis direction) of the recoater body (100), and is rotatably installed on one side of the feeding roller module (300) inside the recoater body (100), with at least a portion of the lower end protruding from the lower end of the recoater body (100), and can pack the powder material applied to the molding stage (2100) by rotation to form a flat and high-density powder layer.

[0071] At this time, a pair of packing shafts (510, 520) of the packing roller module (500) can be arranged horizontally with respect to the sliding movement direction (X-axis direction) of the recoater body (100).

[0072] For example, the packing roller module (500) may include a first packing shaft (510) which is formed to extend long in a cylindrical shape along the extension direction (Y-axis direction) of the recoater body (100) and is rotatably installed on one side of the feeding roller module (300), and a second packing shaft (520) which is formed to extend long in a cylindrical shape parallel to the first packing shaft (510) along the extension direction (Y-axis direction) of the recoater body (100), is rotatably installed in parallel with the first packing shaft (510), and is positioned horizontally with respect to the sliding movement direction (X-axis direction) of the recoater body (100).

[0073] Additionally, the rotational drive of the packing roller module (500) can be individually controlled by the packing drive unit (530, 540) which is built together with the recoater body (100).

[0074] For example, as illustrated in FIGS. 6 to 9, the packing roller module (500) may further include a first packing drive unit (530) that is installed in a second motor space (MA2) formed on one side of a first motor space (MA1) inside a recoater body (100) and connected to a first packing shaft (510) by a combination of a belt (B3) and a pulley (P3-1, P3-2) to rotate the first packing shaft (510), and a second packing drive unit (540) that is installed symmetrically to the first packing drive unit (530) in the second motor space (MA2) and connected to a second packing shaft (520) by a combination of a belt (B4) and a pulley (P4-1, P4-2) to rotate the second packing shaft (520).

[0075] At this time, each packing drive unit (530, 540) can be connected to the packing shafts (510, 520) at different ends based on the extension direction (Y-axis direction) of the recoater body (100) so as to reduce the installation area within the recoater body (100) and so that the power transmission members (B3, B4, P3-1, P3-2, P4-1, P4-2) installed for individual power transmission with each packing shaft (510, 520) do not interfere with each other.

[0076] For example, as shown in FIGS. 7 and 9, the first packing drive unit (530) is installed at one end of the second motor space (MA2) (right end in FIG. 9) with respect to the extension direction (Y-axis direction) of the recoater body (100), and can be connected to the first packing shaft (510) by a combination of a belt (B3) and pulleys (P3-1, P3-2) at one end of the recoater body (100).

[0077] Additionally, as shown in FIGS. 8 and 9, the second packing drive unit (540) is installed at the other end of the second motor space (MA2) (left end in FIG. 9) with respect to the extension direction (Y-axis direction) of the recoater body (100), and can be connected to the second packing shaft (520) by a combination of a belt (B4) and pulleys (P4-1, P4-2) at the other end of the recoater body (100).

[0078] Here, the power transmission members (B3, B4, P3-1, P3-2, P4-1, P4-2) that individually transmit power between the packing drive members (530, 540) and the packing shafts (510, 520) are exemplified as a belt and pulley combination, but are not necessarily limited thereto; any type of power transmission member capable of individually transmitting power between the packing drive members (530, 540) and the packing shafts (510, 520), such as a chain and sprocket combination or a gear combination, may be applied.

[0079] In this way, the packing roller module (500) can be rotated in different directions according to different purposes by means of a first packing drive unit (530) and a second packing drive unit (540) that are embedded together inside the recoater body (100) so as to individually rotate the first packing shaft (510) and the second packing shaft (520).

[0080] For example, as illustrated in FIG. 6, the feeding roller module (300) can be rotated to apply powder material onto the molding stage (2100) when the recoater body (100) moves linearly forward along the length direction (X-axis direction) of the molding stage (2100) above the molding stage (2100), and the packing roller module (500) can be rotated to pack the powder material applied onto the molding stage (2100) when the recoater body (100), having completed moving forward from the upper side of the molding stage (2100), moves backward to its original standby position.

[0081] At this time, during the packing process of the powder material by the packing roller module (500), the first packing shaft (510), which is located relatively forward relative to the backward movement direction of the recoater body (100), plays the role of flattening the powder material applied on the molding stage (2100) to a certain height, and the second packing shaft (520), which is located relatively backward, plays the role of compressing the flattened powder material to form a powder layer that is flat and high-density.

[0082] In order to perform such a role, the first packing drive unit (530) can rotate the first packing shaft (510), which is located relatively forward when the recoater body (100) moves backward, in the reverse direction relative to the direction of backward movement, and the second packing drive unit (540) can rotate the second packing shaft (520), which is located relatively rearward when the recoater body (100) moves backward, in the forward direction relative to the direction of backward movement.

[0083] More specifically, the second packing drive unit (540) can rotate the second packing shaft (520) such that the linear speed of the second packing shaft (520), which rotates in the forward direction relative to the backward movement direction of the recoater body (100), is equal to the backward movement speed of the recoater body (100).

[0084] At this time, the first packing shaft (510) and the second packing shaft (520) may be formed to basically have the same diameter (D1, D2), but in order to increase the pressing force and pressing speed of the second packing shaft (520), the second packing shaft (520) may be formed as a shaft having a second diameter (D2) that is larger than the first diameter (D1) of the first packing shaft (510).

[0085] Additionally, the packing roller module (500) may further include a blade unit (570) that is formed to extend long in a blade shape along the extension direction of the recoater body (100), is installed so that its end contacts the outer diameter surface of the second packing shaft (520) inside the recoater body (100), and can wipe and remove powder material attached to the second packing shaft (520) when the second packing shaft (520) is rotated.

[0086] In this way, the packing roller module (500) further includes a blade unit (570) to compress the applied powder material, thereby easily removing the powder material remaining on the outer diameter surface of the second packing shaft (520) to which the powder material can adhere better. Additionally, although the blade unit (570) is exemplified as being installed only on the side of the second packing shaft (520), it is not necessarily limited thereto and may also be installed on the side of the first packing shaft (510).

[0087] Additionally, the packing roller module (500) may further include a first packing belt tensioner (550) installed at one end of the recoater body (100) to maintain the tension of the belt (B3) by pressing the belt (B3) connecting the first packing drive unit (530) and the first packing shaft (510), and a second packing belt tensioner (560) installed at the other end of the recoater body (100) to maintain the tension of the belt (B4) by pressing the belt (B4) connecting the second packing drive unit (540) and the second packing shaft (520).

[0088] As shown in FIGS. 6 and 9, the stirring roller (400) is formed to extend in a cylindrical or polygonal column shape along the extension direction (Y-axis direction) of the recoater body (100), is rotatably installed in the storage space (A) of the powder chamber (200), and can stir the powder material stored in the storage space (A) by rotation so that it spreads evenly along the extension direction (Y-axis direction) of the recoater body (100) without clumping.

[0089] Such a stirring roller (400) can be rotated by a stirring drive unit (430) installed at the other end of the recoater body (100).

[0090] Additionally, as shown in FIGS. 9 and 10, the stirring roller (400) may be formed such that a plurality of protrusions (410) formed to protrude from the outer surface are arranged at predetermined intervals along the extension direction and radial direction of the stirring roller (400).

[0091] Such a protrusion (410) can be screw-coupled to a screw groove (420) formed on the outer surface of the stirring roller (400) and can be replacedly coupled to the stirring roller (400). Accordingly, protrusions (410) of various shapes can be replaced depending on the characteristics of the powder material stored in the powder chamber (200). For example, although the shape of the protrusion (410) is shown as a headless bolt shape, it is not necessarily limited to the shape of FIG. 10, and various bolt members such as a hexagonal bolt shape or a wrench bolt shape, or protrusion members having various customized shapes such as a cone shape or a pyramid shape, can be replaced.

[0092] Accordingly, according to the recoater device (3100) and the 3D printer (1) including the same according to various embodiments of the present invention, by rotatably installing a pair of feeding shafts (310, 320) of a feeding roller module (300) that controls the amount of powder material applied in a coating slit (210) in the recoater device (3100) and arranging them at an optimized predetermined inclination angle (a) derived from prior experiments, even when a tolerance in the straightness of the pair of feeding shafts (310, 320) occurs, the phenomenon of powder material leaking through the gap space (G) between the pair of feeding shafts (310, 320) can be prevented, and the excessive load on the feeding drive unit (330, 340) that drives each of the pair of feeding shafts (310, 320) due to an excessively narrow gap space (G) can be prevented.

[0093] Additionally, a packing roller module (500) is installed on one side of the feeding roller module (300) to pack the applied powder material by applying pressure and flattening it, so that when the recoater body (100) moves forward to apply the powder material and moves backward, the powder material applied on the molding stage (2100) can be packed into a high-density powder layer having a uniform thickness.

[0094] In addition, by implementing a structure in which a pair of feeding shafts (310, 320) of the above-described feeding roller module (300), a pair of packing shafts (510, 520) of the packing roller module (500), driving units (330, 340, 530, 540) that individually drive these shafts, and power transmission members (B1, B2, B3, B4, P1-1, P1-2, P2-1, P2-2, P3-1, P3-2, P4-1, P4-2) are integrally embedded inside the recoater body (100), the shafts (310, 320, 510, 520) and power transmission members (B1, B2, B3, B4, P1-1, P1-2, P2-1, P2-2, P3-1, P3-2, P4-1, P4-2) By preventing contamination by the external environment, the maintenance cycle can be increased, and more precise operation can be expected.

[0095] Therefore, by applying a powder material in a precise amount without leakage of the powder material on the molding stage (2100) and packing the applied powder material into a flattened high-density powder layer, a recoater device (3100) and a 3D printer (1) including the same can be implemented to improve the precision and strength of a 3D model formed by 3D printing.

[0096] The present invention has been described with reference to the embodiments illustrated in the drawings, but this is merely illustrative, and those skilled in the art will understand that various modifications and equivalent alternative embodiments are possible therefrom. Accordingly, the true technical scope of protection of the present invention should be determined by the technical spirit of the appended claims. Explanation of the symbols

[0097] 1: 3D printer 100: Recoater body 110: A pair of flange sections 200: Powder chamber 210: Coating slit 300: Feeding roller module 310: 1st Feeding Shaft 320: Second feeding shaft 330: 1st feeding drive unit 340: Second feeding drive unit 350: 1st feeding belt tensioner 360: Second feeding belt tensioner 400: Stirring roller 410: Protrusion 420: Screw groove 430: Stirring drive unit 500: Packing roller module 510: 1st packing shaft 520: Second packing shaft 530: 1st packing drive unit 540: Second packing drive unit 550: 1st packing belt tensioner 560: Second packing belt tensioner 570: Blade Unit 1000: Main body 2000: Molding box module 2100: Sculpting Stage 3000: Powder application module 3100: Recoater device 3200: Hopper section 4000: Printing module 4100: Printing head 4200: Printing head drive unit 5000: Cleaning Station Module 5100: Cleaning Stage 5200: Injection stage 5300: Waiting Stage R: A pair of rail sections A: Storage space G: Gap space B1, B2, B3, B4: Belt P1-1, P1-2, P2-1, P2-2, P3-1, P3-2, P4-1, P4-2: Pulley MA1: 1st motor space MA2: Second motor space

Claims

Claim 1 A recoater body formed to extend long along the width direction of a molding stage on which a powder material is applied so as to form a three-dimensional object by 3D printing, and installed above the molding stage so as to be slidably movable along the length direction of the molding stage; a powder chamber formed to extend long along the extension direction of the recoater body inside the recoater body so as to form a storage space for storing the powder material to be applied to the molding stage, and having a coating slit formed on the lower side for applying the powder material downward; and a feeding roller module formed by a pair of feeding shafts extending in a cylindrical shape along the extension direction of the recoater body, rotatably installed at a position corresponding to the coating slit below the powder chamber inside the recoater body, and applying the powder material through the gap space between the pair of feeding shafts by rotation; wherein the pair of feeding shafts are arranged such that a virtual line segment connecting the rotation axes of each shaft forms a predetermined angle of inclination with respect to the sliding movement direction of the recoater body, which reciprocally slides along the length direction of the molding stage, and the feeding roller module includes a first feeding shaft that extends in a cylindrical shape along the extension direction of the recoater body and is rotatably installed at a position corresponding to the coating slit; A recoater device comprising: a second feeding shaft that is formed to extend long in a cylindrical shape parallel to the first feeding shaft along the extension direction of the recoater body, and is rotatably installed at a position corresponding to the coating slit so as to be arranged parallel to the first feeding shaft to form the gap space between the first feeding shaft and the second feeding shaft, and is positioned at a position inclined upward from the first feeding shaft. Claim 2 delete Claim 3 A recoater device according to claim 1, wherein the predetermined inclination angle between the first feeding shaft and the second feeding shaft is formed as an inclination angle between 60 and 80 degrees with respect to any one sliding movement direction of the recoater body that moves back and forth and reciprocally sliding along the longitudinal direction of the molding stage. Claim 4 A recoater device according to claim 1, wherein the feeding roller module further comprises: a first feeding drive unit installed in a first motor space formed on one side of the powder chamber inside the recoater body and connected to the first feeding shaft by a belt and pulley combination to rotate the first feeding shaft; and a second feeding drive unit installed in the first motor space and connected to the second feeding shaft by a belt and pulley combination to rotate the second feeding shaft. Claim 5 A recoater device according to claim 4, wherein the first feeding drive unit is installed on the side of one end of the first motor space with respect to the extension direction of the recoater body and is connected to the first feeding shaft by a belt and pulley combination at one end of the recoater body, and the second feeding drive unit is installed on the side of the other end of the first motor space with respect to the extension direction of the recoater body and is connected to the second feeding shaft by a belt and pulley combination at the other end of the recoater body. Claim 6 A recoater device according to claim 4, wherein the feeding roller module further comprises: a first feeding belt tensioner installed at one end of the recoater body to press a belt connecting the first feeding drive unit and the first feeding shaft; and a second feeding belt tensioner installed at the other end of the recoater body to press a belt connecting the second feeding drive unit and the second feeding shaft. Claim 7 A recoater device according to claim 1, further comprising: a stirring roller formed to extend long in a cylindrical or polygonal columnar shape along the extension direction of the recoater body, rotatably installed in the storage space of the powder chamber, and stirring the powder material stored in the storage space by rotation. Claim 8 In claim 7, the stirring roller is formed such that a plurality of protrusions formed to protrude from the outer surface are arranged at predetermined intervals along the extension direction and radial direction of the stirring roller, forming a recoater device. Claim 9 A recoater device according to claim 8, wherein the protrusion is screw-coupled to a screw groove formed on the outer surface of the stirring roller and is replaceably coupled to the stirring roller. Claim 10 A recoater device according to claim 1, further comprising: a packing roller module formed by a pair of packing shafts extending in a cylindrical shape along the extension direction of the recoater body, rotatably installed on one side of the feeding roller module inside the recoater body, wherein at least a portion of the lower end protrudes from the lower end of the recoater body, and packing by pressing and flattening the powder material applied to the molding stage by rotation. Claim 11 A recoater device according to claim 10, wherein the feeding roller module is driven to rotate so as to apply the powder material onto the molding stage when the recoater body moves forward on the upper side of the molding stage, and the packing roller module is driven to rotate so as to pack the powder material applied onto the molding stage when the recoater body moves backward after completing forward movement on the upper side of the molding stage. Claim 12 A recoater device according to claim 11, wherein the packing roller module comprises: a first packing shaft rotatably installed on one side of the feeding roller module; and a second packing shaft rotatably installed parallel to the first packing shaft, and positioned horizontally with respect to the sliding movement direction of the recoater body. Claim 13 In claim 12, the packing roller module further comprises: a first packing drive unit installed in a second motor space formed on one side of a first motor space inside the recoater body and connected to the first packing shaft by a belt and pulley combination to rotate the first packing shaft; and a second packing drive unit installed in the second motor space and connected to the second packing shaft by a belt and pulley combination to rotate the second packing shaft. Claim 14 A recoater device according to claim 13, wherein the first packing drive unit is installed on the side of one end of the second motor space with respect to the extension direction of the recoater body and is connected to the first packing shaft by a belt and pulley combination at the side of the recoater body, and the second packing drive unit is installed on the side of the other end of the second motor space with respect to the extension direction of the recoater body and is connected to the second packing shaft by a belt and pulley combination at the other end of the recoater body. Claim 15 A recoater device according to claim 13, wherein the packing roller module further comprises: a first packing belt tensioner installed at one end of the recoater body to press a belt connecting the first packing drive unit and the first packing shaft; and a second packing belt tensioner installed at the other end of the recoater body to press a belt connecting the second packing drive unit and the second packing shaft. Claim 16 A recoater device according to claim 13, wherein the first packing drive unit rotates the first packing shaft located relatively forward when the recoater body moves backward in the reverse direction relative to the direction of backward movement, and the second packing drive unit rotates the second packing shaft located relatively rearward when the recoater body moves backward in the forward direction relative to the direction of backward movement. Claim 17 In claim 16, the second packing drive unit rotates the second packing shaft such that the linear velocity of the second packing shaft, which rotates in the forward direction, is equal to the reverse movement speed of the recoater body, in a recoater device. Claim 18 In claim 12, the recoater device wherein the second packing shaft is formed as a shaft having a larger diameter than the first packing shaft. Claim 19 A recoater device according to claim 12, further comprising: a blade unit in which the packing roller module is formed to extend in a blade shape along the extension direction of the recoater body, is installed such that its end contacts the second packing shaft inside the recoater body, and removes the powder material attached to the second packing shaft when the second packing shaft is rotated. Claim 20 A molding box module comprising a molding stage formed in a box shape with an open top so as to form a molding space in which a powder material can be received and a three-dimensional object can be molded, and which is movably mounted inside so as to form a plurality of layers of the three-dimensional object on the upper surface; and a powder coating module comprising a recoater device installed movably on the upper side of the molding box module to apply the powder material so as to form a powder layer on the molding stage. The printing module includes a printing head that is movably installed on the upper side of the molding box module and sprays a liquid material containing a binder onto the powder layer formed on the molding stage; and the recoater device comprises: a recoater body formed to extend long along the width direction of the molding stage and installed to slide movably along the length direction of the molding stage on the upper side of the molding stage; a powder chamber formed to extend long along the extension direction of the recoater body inside the recoater body so as to form a storage space for storing the powder material to be applied to the molding stage, and having a coating slit formed on the lower side for applying the powder material downward; and a feeding roller module formed by a pair of feeding shafts that extend long in a cylindrical shape along the extension direction of the recoater body, rotatably installed on the recoater body at a position corresponding to the coating slit on the lower side of the powder chamber, and applying the powder material through the gap space between the pair of shafts by rotation.A 3D printer comprising: a pair of feeding shafts, wherein a virtual line segment connecting the rotation axes of each shaft is arranged to form a predetermined angle of inclination with respect to the sliding movement direction of the recoater body, which reciprocally slides along the length direction of the molding stage; a feeding roller module comprising: a first feeding shaft formed to extend long in a cylindrical shape along the extension direction of the recoater body and rotatably installed at a position corresponding to the coating slit; and a second feeding shaft formed to extend long in a cylindrical shape parallel to the first feeding shaft along the extension direction of the recoater body, rotatably installed at a position corresponding to the coating slit so as to be arranged parallel to the first feeding shaft to form the gap space between the first feeding shaft and the second feeding shaft, and positioned at a position inclined upward from the first feeding shaft.

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