KR102485871B1 - Divided recoater type powder feeder, three-dimensional printer and its control method - Google Patents

Abstract

The present invention relates to a powder coating device of a split recoater type that allows unit coaters to individually move up and down according to the three-dimensional surface shape of a preform and apply powder to the surface of a preform, a 3D printer, and A method for controlling the same, comprising: a split recoater device in which a plurality of unit recoaters that can move up and down along the surface of the pre-molded body are installed in a line while moving along the surface of the pre-molded body; and the split recoater device so that when the split recoater device moves forward and backward, powder is discharged through a powder discharge port formed below the split recoater device, and the discharged powder can be applied to the surface of the preliminary molded body. It may include; a powder supply device capable of supplying the powder to the powder receiving space formed therein.

Description

Divided recoater type powder coating device, three-dimensional printer and its control method {Divided recoater type powder feeder, three-dimensional printer and its control method}

The present invention relates to a split recoater-type powder coating device, a 3D printer, and a control method thereof, and more particularly, unit recoaters are individually raised and lowered according to the 3D surface shape of a preliminary molded body, thereby forming a preliminary mold. It relates to a powder application device of a split recoater type capable of applying powder to the surface of a mold, a 3D printer, and a control method thereof.

The molding method of a 3D printer using a powder bed is to form a powder layer by thinly spreading the powder, which is the material layer by layer, and then selectively according to the cross-sectional information of the desired shape using a heat source such as a laser or an electron beam. It is a method of manufacturing by melting and stacking them in multiple layers.

In the powder supply bed type 3D printer, a kind of blade-shaped recoater may be installed to thinly spread powder on the molding bed while moving forward and backward from the powder supply bed to the molding bed in which molding is performed.

Such a recoater necessarily required a powder supply bed capable of being raised and lowered step by step so as to supply powder to one side or both sides of the molding bed.

Recently, a split type recoater capable of individually moving up and down has been used because each part is divided so that powder can be applied to the surface of a three-dimensional preform.

Even in this case, a powder supply bed that can be raised and lowered step by step was required to supply powder to one or both sides of the molding bed, and both conventional recoaters and split recoaters reciprocate the powder supply bed and the molding bed while reciprocating. The powder could be applied by drawing the powder to the surface of the preform.

However, while the 3D printer using a conventional powder bed has superior molding precision and freedom of shape compared to the 3D printer method of directly spraying powder, it is possible to obtain a preliminary 3D shape manufactured by traditional manufacturing processes such as mechanical processing and plastic processing. It was impossible to utilize the shape to additionally implement only complex shapes.

The present invention is to solve various problems including the above problems, and it is possible to greatly reduce the molding time by simultaneously performing powder ejection and powder application using a split type recoater capable of powder ejection, thereby greatly reducing the powder The entire supply bed can be omitted, so the space utilization of the equipment can be greatly improved, and only complex shapes can be additionally manufactured using the preliminary molded body manufactured by the low-cost traditional manufacturing process, thereby improving product production speed, reducing costs, and manufacturing large-sized products. A split recoater-type powder coating device that can greatly improve the performance of the equipment because it can apply the powder layer very precisely according to the shape or surface inclination of the preform, 3D printer, and Its object is to provide a control method thereof. However, these tasks are illustrative, and the scope of the present invention is not limited thereby.

The split recoater type powder coating device according to the spirit of the present invention for solving the above problems is a plurality of unit recoaters that can be moved up and down along the surface height of the preform while moving along the surface of the preform a split recoater device installed so as to form a line; and the split recoater device so that when the split recoater device moves forward and backward, powder is discharged through a powder discharge port formed below the split recoater device, and the discharged powder can be applied to the surface of the preliminary molded body. It may include; a powder supply device capable of supplying the powder to the powder receiving space formed therein.

In addition, the split recoater-type powder application device according to the present invention, the split recoater device can be moved along the surface of the preliminary molded body in the X-axis direction based on the molding bed on which the preliminary molded body is seated. a forward and backward movement device for forward and backward movement of the split recoater device; and a unit recoater lifting and lowering device installed on each of the unit recoaters so that each of the unit recoaters arranged in a row in the Y-axis direction can independently move up and down in the Z-axis direction.

Further, according to the present invention, the split recoater device includes: a left guide formed at a left end and made up of a front wall, a rear wall, and a left chamber wall connecting left surfaces of the front wall and the rear wall to each other; a right guide formed at a right end and comprising a front wall, a rear wall, and a right side wall connecting right sides of the front wall and the rear wall to each other; and a plurality of unit recoaters installed between the left guide and the right guide to be able to slide up and down, the powder outlet being formed below, and a front wall and a rear wall spaced apart from the front wall. can include

In addition, according to the present invention, the split recoater device engages opposite surfaces between the unit recoater and the adjacent unit recoater so that the unit recoaters can individually move up and down so that the powder does not leak to the outside. A rail part or a sealing part may be formed.

Further, according to the present invention, the powder discharge port may be an integrated powder discharge port formed in a form integrated and connected to each other at the lower ends of the plurality of unit recoaters.

Further, according to the present invention, the powder outlet may be an individual powder outlet formed in an independent form at the lower end of the plurality of unit recoaters.

In addition, the split recoater type powder coating device according to the present invention includes a surface height measurement sensor installed in front or rear of the split recoater device to measure the surface height of the preform; and a control unit receiving a height signal of the surface of the preform from the surface height measurement sensor and applying a forward and backward movement speed control signal to the forward and backward moving device or a lifting and lowering control signal to the unit recoater raising and lowering device. ; may be further included.

In addition, the split recoater-type powder application device according to the present invention may further include a vibration device installed on at least a part of the split recoater device so that the powder can be smoothly supplied through the powder outlet. .

In addition, according to the present invention, the unit recoater elevating device includes a front wall elevating device for elevating and lowering the front wall so that the height of the front wall can be adjusted when moving forward or backward; and a rear wall lifting and lowering device that lifts and lowers the rear wall to adjust the height of the rear wall when moving forward or backward.

In addition, in the split recoater-type powder application device according to the present invention, when the unit recoater moves forward, an elevation control signal is sent to the front wall elevating and descending device so that the height of the front wall is higher than the height of the rear wall. or applying a lowering control signal to the rear wall lifting and lowering device, and when the unit recoater moves backward, a lowering control signal to the front wall raising and lowering device so that the height of the rear wall is higher than the height of the front wall or a controller for applying a lift control signal to the rear wall elevating device.

In addition, according to the present invention, the control unit, along the surface inclination angle of the preform, when the surface inclination angle is equal to or greater than a reference value, applies a speed reduction control signal to the forward and backward movement device or lifts to the rear wall elevating device. A control signal can be applied.

On the other hand, the 3D printer according to the spirit of the present invention for solving the above problems may include the above-described split recoater type powder coating device.

On the other hand, the control method of the split recoater type powder coating device according to the spirit of the present invention for solving the above problems is, while moving along the surface of the pre-form body, it can be raised and lowered along the surface height of the pre-form body a split recoater device in which a plurality of unit recoaters are installed in a line; and the split recoater device so that when the split recoater device moves forward and backward, powder is discharged through a powder discharge port formed below the split recoater device, and the discharged powder can be applied to the surface of the preliminary molded body. In the control method of a split recoater type powder coating device comprising a powder supply device capable of supplying the powder to a powder receiving space formed therein, (a) the split recoater device is applied to the surface of the preform moving along; and (b) discharging the powder through the powder outlet while moving the unit recoaters up and down along the surface height of the pre-form and simultaneously applying the powder to a constant thickness on the surface of the pre-form; can include

According to some embodiments of the present invention made as described above, it is possible to greatly reduce the molding time by simultaneously performing powder ejection and powder application using a split type recoater capable of powder ejection, and through this, the powder supply bed All of them can be omitted, so the space utilization of the equipment can be greatly improved, and by using the preliminary molded body manufactured by the low-cost traditional manufacturing process, only complex shapes can be additionally manufactured, thereby improving product production speed, reducing costs, and manufacturing large-sized products. , the powder layer can be applied very accurately according to the shape or surface inclination of the preform, so the performance of the equipment can greatly improve the accuracy. Of course, the scope of the present invention is not limited by these effects.

1 is a perspective view showing a split recoater-type powder coating device and a 3D printer according to some embodiments of the present invention.
Fig. 2 is a front view showing the powder coating device of the split recoater type of Fig. 1;
Fig. 3 is a plan view showing the powder coating device of the split recoater type of Fig. 1;
FIG. 4 is a side cross-sectional view showing the split recoater-type powder application device of FIG. 1;
5 is a plan view illustrating a sealing part of a powder coating device of a split recoater type according to some other embodiments of the present invention.
6 is a plan view illustrating a powder application device of a split recoater type according to some other embodiments of the present invention.
7 is a side cross-sectional view showing a forward mode of a powder coating device of a split recoater type according to some other embodiments of the present invention.
FIG. 8 is a side cross-sectional view showing the reverse mode of the split recoater-type powder coating device of FIG. 7 .
9 is a flowchart illustrating a control method of a split recoater type powder coating device according to some embodiments of the present invention.

Hereinafter, several preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art, and the following examples may be modified in many different forms, and the scope of the present invention is as follows It is not limited to the examples. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will 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.

1 is a perspective view showing a split recoater type powder coating device 100 and a 3D printer 1000 according to some embodiments of the present invention, and FIG. 2 is a split recoater type powder coating device of FIG. 1 ( 100), FIG. 3 is a plan view showing the split recoater-type powder coating device 100 of FIG. 1, and FIG. 4 is a side cross-sectional view showing the split recoater-type powder coating device 100 of FIG. to be.

First, as shown in FIG. 1, the split recoater type powder application device 100 according to some embodiments of the present invention includes a split recoater device 10, a powder supply device 20, It may include a forward and backward moving device 30 and a unit recoater lifting and lowering device 40 .

For example, the split recoater device 10 includes a plurality of unit recoaters 13 that can move up and down along the surface height of the pre-molded body 1 while moving forward and backward along the surface of the pre-molded body 1 ) can be installed in a row.

More specifically, for example, as shown in FIGS. 1 to 4, the split recoater device 10 includes a left guide 11, a right guide 12, and a plurality of unit recoaters 13. can include

For example, as shown in FIG. 3, the left guide 11 is formed at the left end of the split recoater device 10, and has a front wall 11a and a rear spaced apart from the front wall 11a. It may consist of a wall 11b and a left room wall 11c connecting left surfaces of the front wall 11a and the rear wall 11b to each other.

Here, as shown in FIG. 3, the left guide 11 may have the powder accommodating space formed therein so as to accommodate as much powder P as possible therein, but such a left guide ( 11) can be moved forward and backward by the forward and backward moving device 30 while guiding the individual lifting and lowering movements of the unit recoaters 13, and are not necessarily limited to the drawing, and can serve as a guide Various rod-shaped guides can all be applied.

For example, as shown in FIG. 3, the right guide 12 is formed at the right end of the split recoater device 10, and has a front wall 12a and a rear spaced apart from the front wall 12a. It may consist of a wall 12b and a right side wall 12c connecting right sides of the front wall 12a and the rear wall 12b to each other.

Here, as shown in FIG. 3, the right guide 12 may have the powder accommodating space formed therein so as to accommodate as much of the powder P as possible therein, but the right guide ( 12) can be moved forward and backward by the forward and backward moving device 30 while guiding the individual lifting and lowering movements of the unit recoaters 13, and are not necessarily limited to the drawing, and can serve as a guide Various rod-shaped guides can all be applied.

In addition, as shown in FIGS. 1 to 4, for example, a plurality of unit recoaters 13 are installed so that they can slide up and down between the left guide 11 and the right guide 12. As such, the powder discharge port (H) is formed below, the front wall (13a) and the rear wall (13b) spaced apart from the front wall (13a) and the front wall (13a) and the rear wall (13b) are mutually connected. It may be made of a connecting portion (13c) to connect.

Here, the unit recoaters 13 may form a line and be arranged side by side in the Y-axis direction, and may be separated from each other and contacted to enable sliding elevation.

That is, as shown in FIGS. 1 to 4, units adjacent to the unit recoaters 13 can individually slide up and down the unit recoaters 13 so that the powder P does not leak to the outside. Interlocking rail portions R may be formed on opposite surfaces between the recoaters 13 .

Here, the unit recoater 13 or the rail unit R is not necessarily limited to the drawings, and unit recoaters of various shapes capable of sliding up and down or rail units of various shapes engaged with each other may be applied.

Therefore, each of the unit recoaters 13 can be separated from each other and independently slide up and down, and in the process, a gap is generated through which the powder P can escape using the rail part R Since the powder P does not leak to the outside, it can be discharged downward only through the powder discharge port H by gravity.

Here, as shown in FIGS. 1 to 4, the powder outlet (H) is an integrated powder outlet formed in the form of a slot that is integrated with each other at the lower end of the plurality of unit recoaters 13 and connected long in the longitudinal direction (H1).

The powder 1 may be discharged in a uniform amount over the entire area of the preform 1 through the integrated powder discharge port H1.

On the other hand, as shown in FIGS. 1 to 4 , the powder supply device 20, when the split recoater device 10 moves forward and backward, the powder discharge port formed below the split recoater device 10 Powder (P) is discharged through (H), and the powder (P) discharged on the surface of the preform 1 is applied to the powder accommodation space formed inside the divided recoater device (10) As a device capable of supplying the powder (P), before the forward and backward movement of the split recoater device (10), the powder (P) is supplied in advance to the powder accommodating space, or the split recoater device (10) ), the powder (P) may be simultaneously supplied to the powder accommodating space.

Here, in the drawings, the powder supply device 20 is shown in the form of a supply pipe, but this is illustrated for ease of understanding, and in addition, various ducts, hoppers, bellows pipes, and powder transfer pipes in the form of pipes are all can be applied

Meanwhile, for example, as shown in FIGS. 1 to 4 , the forward and backward moving device 30 is configured to move the split recoater device 10 along the surface of the preform 1 . Various motors, linear motors, actuators, piston/cylinder combinations, threaded rods/gears that move the split recoater device 10 forward and backward in the X-axis direction based on the molding bed 2 on which the preliminary molded body 1 is seated Various types of moving devices such as combinations, gear combinations, belt/pulley combinations, chain/sprocket wheel combinations, and wire/pulley combinations can all be applied.

In addition, for example, as shown in FIGS. 1 to 4 , in the unit recoater lifting and lowering device 40, each of the unit recoaters 13 arranged in a row in the Y-axis direction is independently moved in the Z-axis direction. Bell motor, linear motor, actuator, piston/cylinder combination, screw rod/gear combination, gear combination, belt/pulley combination, chain/sprocket wheel combination installed on each of the unit recoaters 13 so that they can be moved up and down by , a wire/pulley combination, etc. can all be applied to very diverse types of elevating and descending devices.

In addition, for example, as shown in FIG. 4 , the split recoater type powder coating device 100 according to some embodiments of the present invention is installed in front or rear of the split recoater device 10 to A surface height measuring sensor 50 for measuring the surface height of the preliminary molded body 1 and a height signal of the surface of the preliminary molded body 1 are received from the surface height measuring sensor 50, and the forward and backward moving device 30 ) or a control unit 60 for applying a forward/reverse movement speed control signal to the unit recoater lifting and lowering device 40 .

Therefore, the surface height of the preform 1 is measured when the split recoater device 10 moves forward and backward using the surface height measurement sensor 50, and the height of the unit recoaters 13 is increased by the measured height. You can adjust the height of the descent or adjust the speed of movement.

For example, not only can the heights of the unit recoaters 13 be automatically adjusted according to the measured height of the pre-form 1, but also when the height of the pre-form 1 changes rapidly, A forward and backward movement speed of the split recoater device 10 may be controlled slowly so as to prevent the powder P from collapsing.

In addition, for example, as shown in FIG. 4, in the powder coating device 100 of the split recoater type according to some embodiments of the present invention, the powder can be smoothly supplied through the powder discharge port H A vibration device 70 installed on at least a portion of the split recoater device 10 may be further included. More specifically, for example, the vibration device 70 may be a three-axis ultrasonic vibration device capable of performing X-axis vibration, Y-axis vibration, and Z-axis vibration.

Therefore, when moving forward and backward using the split recoater type powder application device 100 of the present invention, powder ejection and powder application are simultaneously performed, thereby greatly reducing the molding time, thereby omitting the powder supply bed altogether. It is possible to greatly improve the space utilization of the equipment, and it is possible to improve product production speed, reduce costs, and manufacture large-sized products by additionally manufacturing only complex shapes by using preliminary moldings manufactured in a low-cost traditional manufacturing process. Depending on the shape of the surface or the slope of the surface, the powder layer can be applied very precisely, so the performance of the equipment can greatly improve the precision.

5 is a plan view showing a sealing part S of a powder coating device 200 of a split recoater type according to some other embodiments of the present invention.

As shown in FIG. 5, the split recoater device 10 includes the unit recoater 13 and the unit recoater 13 so that the unit recoaters 13 can individually move up and down so that the powder P does not leak to the outside. A sealing portion S may be formed on the opposite surface between adjacent unit recoaters 13 .

Therefore, each of the unit recoaters 13 can be separated from each other and independently slide up and down, and in the process, a gap is generated through which the powder P can escape using the sealing part S. Since the powder P does not leak to the outside, it can be discharged downward only through the powder discharge port H by gravity.

6 is a plan view showing a powder application device 300 of a split recoater type according to some other embodiments of the present invention.

As shown in FIG. 6, the powder discharge port H of the powder coating device 300 of the split recoater type according to some other embodiments of the present invention is located at the lower ends of the plurality of unit recoaters 13. It may be a plurality of individual powder outlets H2 each formed in an independent form. Therefore, it is possible to individually control the more precise discharge amount of the powder (P) using the plurality of individual powder discharge ports (H2).

Here, although the individual powder outlet H2 is illustrated in a quadrangular shape in the drawing, it may be formed in a variety of shapes, such as a circular shape, an elliptical shape, a polygonal shape, or a porous body shape, depending on the type of product or the molding environment.

7 is a side cross-sectional view showing a forward mode of a split recoater type powder application device 400 according to some other embodiments of the present invention, and FIG. 8 is a split recoater type powder application device 400 of FIG. ) is a side cross-sectional view showing the reverse mode.

7 and 8, the unit coater lifting and lowering device 40 of the split coater type powder coating device 400 according to some other embodiments of the present invention, when moving forward or backward The front wall elevating device 80-1 that lifts and lowers the front wall 13a so that the height of the front wall 13a can be adjusted during movement, and the height of the rear wall 13b can be adjusted during forward or backward movement. A rear wall elevating device 80-2 for elevating and lowering the rear wall 13b may be included.

Here, in the split recoater type powder application device 400 according to some other embodiments of the present invention, when the unit recoater 13 of FIG. 7 moves forward, the height of the front wall 13a is Applying a lift control signal to the front wall elevating device 30-1 or applying a lowering control signal to the rear wall elevating device 80-2 so as to be higher than the height of the rear wall 13b, When the unit recoater 13 of 8 moves backward, a lowering control signal is sent to the front wall elevating device 80-1 so that the height of the rear wall 13b can be higher than the height of the front wall 13a. A control unit 90 may further include a control unit 90 for applying a lifting control signal to the rear wall lifting and lowering device 80-2.

When the surface inclination angle of the preform 1 is greater than or equal to a reference value, the control unit 90 applies a speed reduction control signal to the forward/backward movement device 30 or the rear wall climbs. A lifting control signal may be applied to the descending device 80-2.

Therefore, when moving forward using the front wall elevating device 80-1 and the rear wall elevating device 80-2, the front wall 13a is high, so that a large amount of the powder P is sufficiently exposed. The rear wall 13b is low and has a thin thickness so that the powder P can be evenly distributed on the surface of the preform 1.

In addition, when the inclination angle of the surface of the preform 1 is steep, the forward/reverse movement speed is sufficiently slowed down, and the amount of fine collapse due to the steep inclination is calculated in advance to increase the height of the rear wall 13b to prevent further collapse. It can be prevented, and only the correct amount can be applied.

On the other hand, as shown in FIGS. 1 to 8, the present invention includes a split recoater type powder coating device 100, 200, 300, 400 according to various embodiments of the present invention described above. A 3D printer 1000 may be included.

For example, although not shown, the 3D printer 1000 may further include a molding bed, a laser curing device, a binder curing device, various cooling devices, heating devices, and the like.

9 is a flowchart illustrating a control method of a split recoater type powder coating device according to some embodiments of the present invention.

As shown in FIGS. 1 to 9, the control method of the split recoater-type powder coating device 100, 200, 300, and 400 according to some embodiments of the present invention includes (a) the split Moving the recoater device 10 along the surface of the preliminary molded body 1 and (b) moving the unit recoaters 13 up and down along the surface height of the preliminary molded body 1 to remove the powder The method may include discharging the powder P through the discharge port H and at the same time applying the powder P to a surface of the preliminary molded body 1 to a predetermined thickness.

That is, when the split recoater device 10 moves forward, at least a portion of the powder P is discharged through the powder discharge port H, and at the same time, the remaining powder P discharged in advance is transferred to the preliminary molded body ( Since the powder (P) can be applied to the surface of 1) with a certain thickness, the powder ejection operation and the powder application operation are unified to quickly reach the surface of the preform 1 without a separate powder supply bed. The powder (P) can be rapidly applied.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention should be determined by the technical spirit of the appended claims.

1: preliminary molding
2: molding bed
P: powder
10: split recoater device
11: left guide
12: right guide
13: unit recoater
R: rail part
S: sealing part
H: powder outlet
20: powder supply device
30: Forward and backward movement device
40: Unit recoater lifting device
50: surface height measurement sensor
60: control unit
70: vibration device
80-1: front wall lifting device
80-2: Rear wall lifting device
100, 200, 300, 400: split recoater type powder coating device
1000: 3D printer

Claims (13)

a split recoater device in which a plurality of unit recoaters that can move up and down along the surface of the preliminary molded body are installed in a line while moving along the surface of the preliminary molded body; and
When the split recoater device moves forward and backward, powder is discharged through a powder discharge port formed below the split recoater device, and the discharged powder can be applied to the surface of the preliminary molded body. Inside the split recoater device A powder supply device capable of supplying the powder to the powder receiving space formed in;
A powder application device of a split recoater type comprising a. According to claim 1,
a forward and backward movement device for moving the split recoater device forward and backward in an X-axis direction with respect to the molding bed on which the preprint is mounted so that the split recoater device can be moved along the surface of the preprinted body; and
a unit recoater elevation device installed on each of the unit recoaters so that each of the unit recoaters arranged in a row in the Y-axis direction can independently move up and down in the Z-axis direction;
Further comprising, a split recoater type powder application device. According to claim 2,
The split recoater device,
a left guide formed at a left end and comprising a front wall, a rear wall, and a left room wall connecting left surfaces of the front wall and the rear wall to each other;
a right guide formed at a right end and comprising a front wall, a rear wall, and a right side wall connecting right sides of the front wall and the rear wall to each other; and
a plurality of unit recoaters installed between the left guide and the right guide to be able to slide up and down, the powder outlet being formed below, and composed of a front wall and a rear wall spaced apart from the front wall;
A powder application device of a split recoater type comprising a. According to claim 3,
The split recoater device,
A split recoater type powder in which a rail part or a sealing part engaging with each other is formed on the opposite surface between the unit coater and the adjacent unit coater so that the unit coaters can individually ascend and descend so that the powder does not leak to the outside. dispensing device. According to claim 1,
The powder discharge port is an integrated powder discharge port formed in a form integrated and connected to each other at the lower ends of the plurality of unit recoaters, a divided recoater type powder application device. According to claim 1,
The powder ejection port is an individual type powder ejection port formed independently at the lower end of the plurality of unit recoaters. According to claim 2,
a surface height measurement sensor installed at the front or rear of the split recoater device to measure the surface height of the preliminary shaped body; and
a control unit receiving a height signal of the surface of the preform from the surface height measurement sensor and applying a forward/reverse movement speed control signal to the forward/backward movement device or an elevation control signal to the unit recoater elevation device;
Further comprising, a split recoater type powder application device. According to claim 1,
a vibrating device installed on at least a portion of the split recoater device so that the powder can be smoothly supplied through the powder outlet;
Further comprising, a split recoater type powder application device. According to claim 3,
The unit recoater lifting and lowering device,
a front wall lifting and lowering device that lifts and lowers the front wall so that the height of the front wall can be adjusted when moving forward or backward; and
a rear wall lifting and lowering device that lifts and lowers the rear wall to adjust the height of the rear wall when moving forward or backward;
A powder application device of a split recoater type comprising a. According to claim 9,
When the unit retor moves forward, a lifting control signal is applied to the front wall lifting and lowering device or a lowering control signal is applied to the rear wall lifting and lowering device so that the height of the front wall is higher than the height of the rear wall, , When the unit retor moves backward, a lowering control signal is applied to the front wall lifting and lowering device or a lifting control signal is applied to the rear wall raising and lowering device so that the height of the rear wall is higher than the height of the front wall. a control unit;
Further comprising, a split recoater type powder application device. According to claim 10,
The control unit, along the surface inclination angle of the preform, when the surface inclination angle is equal to or greater than a reference value, applies a speed reduction control signal to the forward and backward movement device or an elevation control signal to the rear wall elevating device. Recoater type powder application device. A three-dimensional printer comprising the powder coating device of the split recoater type according to any one of claims 1 to 11. a split recoater device in which a plurality of unit recoaters that can move up and down along the surface of the preliminary molded body are installed in a line while moving along the surface of the preliminary molded body; and the split recoater device so that when the split recoater device moves forward and backward, powder is discharged through a powder discharge port formed below the split recoater device, and the discharged powder can be applied to the surface of the preliminary molded body. In the control method of a split recoater type powder application device comprising a; powder supply device capable of supplying the powder to a powder receiving space formed therein,
(a) moving the split recoater device along the surface of the preform; and
(b) discharging the powder through the powder outlet while moving the unit recoaters up and down along the surface height of the preliminary molded body and simultaneously applying the powder to a constant thickness on the surface of the preliminary molded body;
A method of controlling a powder application device of a split recoater type comprising a.

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