KR20220054524A - Extruder For 3D Printer And Multicolor 3D Printer With The Same - Google Patents

Abstract

The present invention relates to an extruder for a 3D printer and a multi-color 3D printer including the same, capable of implementing multi-color molding for molding a product with a plurality of colors, and minimizing a number of driving motors used and an interval between nozzles. According to the present invention, the extruder for the 3D printer includes: a body into which a filament is introduced; a feeding gear provided inside the body so as to be axially rotatable, and configured to forcibly transfer the filament; a first driving unit for driving the feeding gear; a rotation rod provided inside the body so as to be axially rotatable; a guide bearing provided on the rotation rod, and freely rotatable about a rotation shaft that is parallel to a rotation shaft of the feeding gear; and a second driving unit for generating the axial rotation of the rotation rod. In addition, a plurality of guide bearings are provided in a longitudinal direction of the rotation rod while being spaced apart from each other, and the guide bearings are directed in mutually different directions.

Description

Extruder for 3D printer and multi-color 3D printer having same

The present invention relates to a 3D printer, and more particularly, to an extruder for a 3D printer capable of forming a multi-color product simply and quickly by selecting and supplying a filament of a required color, and a multi-color 3D printer having the same it's about

In recent years, the use of 3D printers that can mold the object as it is by using 3D data on the object is increasing. In the past, these 3D printers were used for purposes such as modeling and sample production before mass production, but recently, a technological foundation that can be used for molding mass-produced products is being established, mainly for small-scale, multi-variety products. is on the brink of expansion.

The 3D printer's product molding method is the so-called additive type, in which a target object is molded into a two-dimensional flat shape and then melted and attached to form a shape by laminating it in three dimensions, and the cutting type, in which a mass of material is cut to form a shape. There is this. And, as an additive type, a wire or filament made of thermoplastic is supplied through a supply reel and a transfer roll, and the supplied filament is melted in a heater nozzle mounted on a three-dimensional transfer mechanism that is positioned in three XYZ directions relative to the workbench. There is a filament melt lamination molding method that forms a three-dimensional object by laminating it on a workbench while making a two-dimensional planar shape by discharging it.

However, the conventional 3D printer that melts and laminates the filaments in this way is capable of molding an article using a filament material of a single color, but is not suitable for molding a product in a plurality of colors. In order to replace the filament supply reel with a filament supply reel of a different color after forming with a filament of one color and replacing it with a filament of a different color, it is necessary to connect or transfer the filament supply reel to the heater nozzle again. , since the already formed molten part is hardened during the waiting time according to the replacement of the filament, a discontinuous seam is formed in the area where the filaments of different colors are melted and attached, and the adhesion of the material at this seam is poor, so the appearance of the product However, there was a problem in that the integrity was lowered, the separation of the material or the structural strength was lowered.

In relation to the conventional multi-color 3D printer for solving this problem, a 3D printer having a multi-print head enabling molding of multi-color products has been proposed. Republic of Korea Patent Registration No. 10-1346704 discloses a 3D printer having a plurality of nozzles capable of molding multi-color products.

However, such a conventional multi-color 3D printer had to be provided with one drive motor for each nozzle for supplying and transferring the filament material. Therefore, if the number of nozzles is configured as multiple, the required driving motor also increases in proportion to this, and accordingly, the system is heavy and the output speed is lowered. there was

Prior Patent 1. Korean Patent Registration No. 10-1441030 (2014.09.05) Prior Patent 2. Korean Patent Registration No. 10-1346704 (2013.12.24)

The present invention has been devised to solve the above problems, and an object of the present invention is to realize multi-color molding for molding a product in a plurality of colors, while minimizing the number of driving motors used and the distance between nozzles. An extruder for a 3D printer and a multi-color 3D printer having the same are provided.

An extruder for a 3D printer according to the present invention for achieving the above object includes: a body into which a filament is introduced; a feeding gear provided axially rotatably inside the body to forcibly feed the filament; a first driving unit for driving the feeding gear; a rotating rod rotatably provided inside the body; a guide bearing provided on the rotating rod and freely rotatable about a rotating axis parallel to the rotating axis of the feeding gear; and a second driving unit for generating shaft rotation of the rotating rod.

In addition, the guide bearings are provided in plural spaced apart from each other along the longitudinal direction of the rotary rod, and the plurality of guide bearings are provided to face different directions from each other.

Thereby, the plurality of guide bearings are configured to selectively contact any one of the plurality of filaments among the plurality of guide bearings according to the degree of axial rotation of the rotary rod by the second driving unit.

According to the extruder for a 3D printer according to the present invention, filaments of various colors can be supplied smoothly and quickly, so that multi-color molding with improved performance can be realized, and the number of driving motors used and the spacing between nozzles can be reduced. It can be minimized, which is advantageous for downsizing the device, and has the effect of minimizing the factor of lowering the output speed.

In addition, there is an advantage that a single-body type multi-nozzle unit can be implemented by integrating the hot-end and cool-end of the nozzle unit including the nozzle and the heat block.

1 is a perspective view of a 3D printer according to the present invention.
Figure 2 is a schematic diagram showing the internal structure of the 3D printer according to the present invention.
3 is a perspective view of a rotating rod and a guide bearing according to the present invention.
Fig. 4 is a side view of Fig. 3;
5 to 8 are operational state diagrams showing a selective filament supply operation of the extruder for a 3D printer according to the present invention.

The terms used in the present invention are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present specification, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

In addition, in this specification, "on or on top of" means to be located above or below the target part, and does not necessarily mean to be located above the direction of gravity. Also, when a part of a region, plate, etc. is said to be "on or on" another part, it means that another part is in contact with or spaced "on or on" another part, as well as another part in between. Including cases where there is

In addition, in this specification, when a component is referred to as "connected" or "connected" with another component, the component may be directly connected or directly connected to the other component, but in particular Unless otherwise stated, it should be understood that they may be connected or connected through another element in the middle.

Also, in this specification, terms such as first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another.

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

The extruder according to the present invention is provided in a 3D printer to supply filaments in an extrusion method. In particular, the extruder of the present invention is a product in multiple colors by a guide bearing structure configured to selectively operate according to a required color. It is characterized in that it can be implemented simply and quickly by multi-color molding for molding.

1 is a perspective view of a 3D printer according to the present invention, FIG. 2 is a schematic view showing an internal structure of the 3D printer according to the present invention, FIG. 3 is a perspective view of a rotating rod and a guide bearing according to the present invention, FIG. 4 is FIG. 3 is a side view of

1 to 4 , the extruder according to the present invention has a body 90 , a feeding gear 10 , a first driving unit 20 , a rotating rod 30 , a guide bearing 40 , and a second driving unit (50).

The body 90 of the present invention is a frame to which a configuration such as a feeding gear 10, a first driving unit 20, a second driving unit 50, and a rotating rod 30 is mounted, and a filament 60 wound from a filament spool. is introduced into the body 90 through the guide tube 91 formed on the body 90 .

The feeding gear 10 of the present invention is provided in the body 90 and is configured to forcibly transport the filament 60 flowing into the body 90 in one direction. Here, the 'one direction' in which the filament 60 is transported means the side of the heat block 70 and the nozzle 80 to be described later.

The feeding gear 10 is configured to have a rotation axis in a direction orthogonal to the direction in which the filament 60 is forcibly transferred, and is configured to be axially rotatable about the rotation axis.

And the feeding gear 10 is driven axially in contact with the filament 60 and is configured to supply the filament 60 in an extrusion manner. Specifically, the feeding gear 10 has a plurality of guide bearings 40 when any one guide bearing selected from among the filaments 60 contacts the filaments 60 and presses the filaments toward the feeding gear 10 due to the increased frictional force to the filaments. is configured to push down in one direction.

According to an embodiment, the feeding gear 10 may have a cylindrical shape, and preferably, a plurality of protrusions may be formed on the outer surface of the feeding gear 10 to increase frictional force with the filament 60 . And, the shaft rotation operation of the feeding gear 10 for forcibly feeding the filament 60 is generated and controlled by the first driving unit 20 to be described later.

The first driving unit 20 of the present invention is a component that is mounted on one side of the body 90 (the right side of the body 90 in FIG. 1 ) and rotates the feeding gear 10 . It is converted into a driving force to axially rotate the feeding gear 10 .

According to an embodiment, the first driving unit 20 includes an electric motor and a power shaft connected to the electric motor, and in this case, the power shaft penetrates the body 90 and has one end protruding into the body 90 .

Then, the feeding gear 10 is connected to one end of the power shaft of the first driving unit 20 and receives rotational force from the electric motor through the power shaft and rotates the shaft, thereby extruding the filament 60 .

Meanwhile, the body 90 may further include a guide tube 91 in a direction orthogonal to the rotational axis of the feeding gear 10 . The guide tube 91 is composed of a tubular body having a hollow communicating with the inside of the body 90 through the upper portion of the body 90 , and the filament 60 is introduced through the inner hollow to be positioned in the body 90 . to be provided as a guide. Here, the 'place in the body 90' means that each of the filaments 60a to 60d is positioned at the rear of each guide bearing 40a to 40d.

The rotary rod 30 of the present invention is disposed at an interval in front of the feeding gear 10 so that the shaft rotation operation is generated by the second driving unit 50 and its driving is controlled.

According to a preferred embodiment, the rotary rod 30 is configured in a rod shape having a long axis in a direction parallel to the rotational axis of the feeding gear 10 , and is axially rotatable about a rotational axis parallel to the rotational axis of the feeding gear 10 . It is provided inside the body 90 .

And, on the outer surface of the rotary rod 30, a plate-shaped support 31 is formed to protrude vertically upward of the rotary rod 30 so that the guide bearing 40 can be mounted on the rotary rod 30, and the support (31) is coupled to the upper shaft 32 for rotatably mounting the guide bearing 40 to the support 31 side.

The second driving unit 50 of the present invention is a component that is mounted on another side of the body 90 (left side of the body 90 in FIG. 1 ) and rotates the rotating rod 30 , and applies an external power source. Received and converted into driving force to rotate the rotating rod 30 shaft.

According to an embodiment, the second driving unit 50 includes an electric motor and a power shaft connected to the electric motor, and in this case, the power shaft penetrates the body 90 and has one end protruding into the body 90 .

Then, the rotary rod 30 is connected to one end of the power shaft of the second driving unit 50 and receives rotational force from the electric motor through the power shaft and rotates the shaft to realize the guide bearing 40 selection operation.

Here, the 'guide bearing 40 selection operation' is an operation for selecting a color required for each lamination step during the molding process of a colored product. It means an operation of positioning the guide bearing 40 in charge of transporting the filament of the corresponding color so as to be in contact with the filament by rotationally moving it. A more detailed description thereof will be given later.

The guide bearing 40 of the present invention is provided on the rotating rod 30 and is configured to be freely rotatable about a rotation axis parallel to the rotation axis of the feeding gear 10 .

The guide bearing 40 presses the filament 60 to increase the frictional force between the filament 60 and the feeding gear 10 so that the filament can be smoothly transferred to the heat block 70 side.

Specifically, when the specific guide bearing 40 moves forward in the feeding gear 10 in order to contact the filament 60 according to the above-described guide bearing selection operation, the guide bearing 40 is in contact with the filament, and It is configured to pressurize it.

Therefore, based on when the guide bearing 40 is in contact with the corresponding filament and positioned in front of the feeding gear 10, the separation distance between the guide bearing 40 and the feeding gear 10 is smaller than the outer diameter of the filament 60. is composed

The guide bearings 40 are provided in plurality, and the plurality of guide bearings 40a to 40d are characterized in that they are spaced apart from each other in horizontal and vertical directions.

Specifically, the plurality of guide bearings 40a to 40d are arranged to be spaced apart from each other in the longitudinal direction of the long axis of the rotary rod 30, that is, along the rotational axis direction, and the plurality of guide bearings 40a to 40d are provided to face different directions. characterized by being Preferably, the separation distances between the plurality of guide bearings 40a to 40d are all the same.

For example, when the first guide bearing 40a among the plurality of guide bearings 40a to 40d is provided on the rotating rod 30 in a protruding structure oriented in the first direction, the second guide bearing 40b is the rotating rod 30 . It may be provided with a protruding structure oriented in a second direction different from the first direction at a position spaced apart from the first guide bearing 40a by a predetermined distance in the longitudinal direction and rotated at a predetermined angle from the first direction.

As a result, the first guide bearing 40a and the adjacent second guide bearing 40b are arranged to be spaced apart from each other by a predetermined distance in the horizontal direction (the longitudinal direction of the rotary rod 30), and by a predetermined rotation angle in the vertical direction. placed in a spaced apart location. Similarly, the third guide bearing 40c adjacent to the second guide bearing 40b, and the fourth guide bearing 40d adjacent to the third guide bearing 40c are also horizontally and vertically spaced apart from each other so that a plurality of guides The bearings 40a to 40d are configured to orient in different directions at mutually different positions.

According to a preferred embodiment, the plurality of guide bearings 40a to 40d are respectively mounted on the plurality of supports 31 protruding on the rotary rod 30 as shown in FIG. 3 through the shaft 32, in which case the plurality of The supports 31 are arranged to be spaced apart from each other at the same interval in the horizontal direction (the longitudinal direction of the rotating rod 30), and are arranged at positions spaced apart from each other by a predetermined rotation angle in the vertical direction, and each of the supports 31 configured in this way By mounting the guide bearing on the , a plurality of guide bearings 40a to 40d can take the structure in which the above-described horizontal and vertical directions are spaced apart from each other.

According to a preferred embodiment, the plurality of guide bearings 40a to 40d include a first guide bearing 40a, a second guide bearing 40b, a third guide bearing 40c, ..., an Nth guide bearing 40n. ), and the first guide bearing 40a, the second guide bearing 40b, the third guide bearing 40c,... It has a difference in rotation angle and is configured to point in mutually different directions.

<Condition 1>

Rotation angle difference = 360°/ N (where N: number of guide bearings)

For example, it is assumed that the guide bearing is composed of four first guide bearings 40a to fourth guide bearings 40d.

In this case, the rotation angle difference is 90° (360°/4), and accordingly, when the first guide bearing 40a is formed at the 0° position, the second guide bearing 40b is greater than the rotation angle difference (that is, It is formed at a position of 90° rotated by 90°), and the third guide bearing 40c is formed at a position of 180° rotated by the difference in rotation angle (ie, 90°) than the second guide bearing 40b, 4 The guide bearing 40d is formed at a position of 270° rotated by the difference in rotation angle (ie, 90°) from the third guide bearing 40c.

Therefore, according to a preferred embodiment of the present invention, the first guide bearing to the N-th guide bearing are provided in a spiral structure on the rotating rod 30 .

Due to the guide bearing structure as described above, the plurality of guide bearings 40a to 40d of the present invention are based on the degree of axial rotation of the rotary rod 30 by the second driving unit 50, and the plurality of guide bearings 40a to 40d ) is selectively configured to contact any one of the plurality of filaments (60a to 60d).

More specifically, in the extruder of the present invention, a plurality of guide bearings 40a to 40d are disposed to be spaced apart from each other in horizontal and vertical directions on the rotating rod 30, and the plurality of guide bearings 40a to 40d provided in this way In 40d), the guide bearing required in the current lamination step is selected by adjusting the rotation angle of the rotary rod 30 .

Here, the 'guide bearing required in the current lamination step' will be described as follows. In the 3D printer of the present invention, a plurality of filaments 60 of various colors are introduced, and the plurality of filaments 60 are arranged and transported in a direction perpendicular to the rotation axis of the feeding gear 10 and the guide bearing 40, and are melt-injected. .

In this way, a plurality of filaments 60 arranged in number are matched with guide bearings responsible for their movement, so, for example, assuming that a red filament is needed in the current lamination stage of a color product currently being molded, the red filament As the guide bearing (referred to as the 'first guide bearing') in charge of transport approaches and comes into contact with the corresponding filament, it forcibly transports the red filament together with the feeding gear. It corresponds to the required guide bearing in the lamination stage.

And, in this way, the selection of the guide bearing required in the current lamination step, that is, the operation in which the first guide bearing approaches and comes into contact with the red filament is achieved through the rotational operation of the rotary rod 30 and the adjustment of the rotational angle.

As a result, the guide bearing in contact with the filament 60 of the desired color among the plurality of filaments 60 is determined by the axial rotation control of the rotating rod 30 .

And, the rotation angle adjustment of the rotary rod 30 for selecting the guide bearing, that is, the shaft rotation control is performed by the above-described second driving unit 50 .

The extruder of the present invention may further include an elastic member for generating an elastic operation of the guide bearing 40 when the guide bearing 40 comes into contact with the filament 60 or is separated from the filament 60 in contact.

According to one embodiment, the elastic member may be composed of a coil spring interlocking with the guide bearing 40, in this case, when the guide bearing 40 comes into contact with the filament 60, the coil spring is elastically compressed, thereby The guide bearing 40 also elastically retreats in the opposite direction to the filament 60 side.

As a result, the elastic member provides an elastic restoring force toward the filament 60 to the guide bearing 40 to ensure a close contact state between the guide bearing and the filament 60, and accordingly, frictional force for smooth transfer of the filament 60 Increase is realized, and at the same time, an elastic retraction operation is caused in the process of contact with the filament 60, so that when the guide bearing comes into contact with the filament 60, excessive external force is applied to prevent the filament 60 from being worn or damaged. do. And, since the guide bearing 40 has elasticity and is in contact with the filament 60 , a constant supply is possible regardless of the thickness of the filament 60 .

Hereinafter, a selective filament transfer operation for multi-color molding will be described with reference to FIGS. 1 to 8 .

5 to 8 are operational state diagrams showing the selective filament supply operation of the extruder for a 3D printer according to the present invention.

First, suppose that a yellow filament, a blue filament, a gray filament, and a red filament are introduced into the body 90 of the multi-color 3D printer of the present invention as shown in FIG. 5 .

And, suppose that injection of yellow (60a) -> blue (60b) -> gray (60c) -> red (60d) filaments are sequentially required in the lamination process for product molding.

(1) Injection of the yellow filament (60a)

First, for the injection of the yellow filament (60a), it is necessary to selectively supply the yellow filament (60a). In this case, the first guide bearing 40a in charge of the transfer of the yellow filament 60a by rotating the rotary rod 30 by a predetermined angle through the control of the second driving unit 50 is the feeding gear 10 as shown in FIG. 5 . Rotate it so that it is positioned forward. When the first guide bearing 40a is moved to the front of the feeding gear 10 by the control, the first guide bearing 40a comes into contact with the yellow filament 60a and presses it, and the frictional force according to the pressure By this, it is possible to forcibly transfer the yellow filament 60a together with the feeding gear 10 to the heat block 70 side, and accordingly, the yellow filament melt can be injected to the outside.

(2) injection of the blue filament (60b)

In the state in which the yellow filament 60a has been injected, when the blue filament 60b is continuously injected, selective supply of the blue filament 60b is required instead of the yellow filament 60a. In this case, when the rotary rod 30 is axially rotated by 90° through the control of the second driving unit 50, the first guide bearing 40a that was pressing the yellow filament 60a as shown in FIG. 6 rotates by 90° The pressure state is released away from the yellow filament (60a), and instead, the second guide bearing (40b) is rotated by 90° to be positioned in front of the feeding gear (10).

Thereby, the second guide bearing 40b comes into contact with the blue filament 60b and presses it, and the blue filament 60b together with the feeding gear 10 by the frictional force according to the pressing toward the heat block 70 side. It becomes possible to forcibly transport, and accordingly, it is possible to inject the blue filament melt to the outside.

(3) Injection of the gray filament (60c)

In a state in which injection of the blue filaments 60b is made, when the injection of the gray filaments 60c is required in succession, the selective supply of the gray filaments 60c instead of the blue filaments 60b is required. In this case, when the rotating rod 30 is axially rotated by 90° through the control of the second driving unit 50, the second guide bearing 40b, which was pressing the blue filament 60b, is rotated by 90° as shown in FIG. The pressure state is released away from the blue filament 60b, and instead the third guide bearing 40c is rotated by 90° to be positioned in front of the feeding gear 10.

Thereby, the third guide bearing 40c comes into contact with the gray filament and presses it, and the gray filament 60c together with the feeding gear 10 is forcibly transferred to the heat block 70 side by the frictional force according to the pressure. It becomes possible, and accordingly, it is possible to inject the gray filament melt to the outside.

(4) Injection of the red filament (60d)

When the injection of the red filament 60d is required in a state in which the gray filament 60c is injected, the third guide bearing 40c is pressed when the rotary rod 30 is axially rotated by 90° in the same principle as described above. The state is released, and instead, the fourth guide bearing 40d comes into contact with the red filament 60d and presses it, whereby the red filament 60d is forcibly transferred and melt-injected.

As a result, in the multi-color 3D printer according to the present invention, the guide bearing selection operation is made through the adjustment of the rotation angle of the rotating rod 30 by the second driving unit 50, whereby filaments of various colors can be individually and selectively supplied. be able to

The extruder of the present invention having the above-described configuration is a filament, a filament spool, a heat block 70, a nozzle 80, and a nozzle 80 injected from The molten filament is laminated and a 3D printer is configured together with the product forming plate on which the product is formed to form a color product.

Filament is formed like a thread by pulling the raw material of a 3D printer long. As a raw material for a 3D printer, a thermoplastic material such as ABS or PLA may be used. And, the filament is provided with a plurality of pieces of various colors.

The filament spool includes a cylindrical reel on which the filament is wound. When the extruder starts to operate, the filament wound on the filament spool is unwound, extruded, and melt-injected through the heat block 70 and the nozzle 80 .

The heat block 70 is a heater for making a fluidized state by heating the solid filament that is introduced into the body 90 through the guide tube 91 and then transferred downward by the feeding gear 10 and the guide bearing. .

The heat block 70 is not particularly limited as long as it can be liquefied by melting solid filaments and can be applied in various ways. For example, a coil-type heater may be used.

The nozzle 80 is configured to inject the filament melted by the heat block 70 to the outside of the extruder. Therefore, the nozzle 80 communicates with the inside of the heat block 70 and is provided on the lower side of the heat block 70 , or the heat block 70 is formed in a structure that surrounds the upper portion of the nozzle 80 to form a heat block 70 and The nozzle 80 may be configured in an integrated or integrated form.

In particular, the nozzle 80 of the present invention is provided in plurality, each nozzle 80 is provided at a position corresponding to the transport direction of each filament. Accordingly, each nozzle 80 has a structure arranged in a straight line with the guide tube 91 and the filament 40 in the vertical direction, and the plurality of nozzles 80a to 80d) of the rotary rod 30 in the horizontal direction. It has a structure arranged along the longitudinal direction of the major axis.

In addition, the spacing distance between the centers of each nozzle 80 is configured to be the same as the spacing distance between the centers of each guide bearing, and the guide bearings are positioned vertically above each nozzle 80 .

In the case of the embodiment of Figure 1, it was composed of four nozzles (80a to 80d). In this case, the first nozzle 80a is located below the conveying direction of the first filament 60a, the second nozzle 80b is located below the conveying direction of the second filament 60b, and the third nozzle 80c ) is located below the conveying direction of the third filament 60c, and the fourth nozzle 80d is configured to be located below the conveying direction of the fourth filament 60d.

By the configuration of the extruder as described above, the 3D printer of the present invention can selectively supply filaments of various colors to implement multi-color molding, while minimizing the number of driving motors used and the spacing between nozzles. Therefore, it is advantageous for the miniaturization of the device, and it is possible to minimize the factor of lowering the output speed.

In the above, preferred embodiments of the present invention have been described and illustrated using specific terms, but such terms are only for clearly describing the present invention, and the embodiments and described terms of the present invention are the spirit and scope of the following claims. It is obvious that various changes and changes can be made without departing from it. Such modified embodiments should not be individually understood from the spirit and scope of the present invention, but should be considered to fall within the scope of the claims of the present invention.

10: feeding gear 20: first driving unit
30: rotating rod 31: support
40: guide bearing 50: second driving unit
60: filament 70: heat block
80: nozzle 90: body
91: information officer

Claims (7)

As an extruder provided in a 3D printer,
a feeding gear provided to be axially rotatable to forcibly feed the filament; a first driving unit for driving the feeding gear; a rotating rod provided to be axially rotatable; a guide bearing provided on the rotary rod and freely rotatable about a rotary shaft parallel to the rotary shaft of the feeding gear; and a second driving unit for generating axial rotation of the rotating rod, wherein the guide bearings are provided in plural spaced apart from each other along the longitudinal direction of the rotating rod, and the plurality of guide bearings are oriented in different directions. is provided, wherein the plurality of guide bearings are configured to selectively contact any one of the plurality of filaments from among the plurality of guide bearings according to the degree of axial rotation of the rotary rod by the second driving unit Extruder for printer.
According to claim 1,
The plurality of guide bearings are provided as a first guide bearing, a second guide bearing, a third guide bearing, and an N-th guide bearing, and the first guide bearing, the second guide bearing, the third guide bearing, and the N-th guide bearing are Extruder for 3D printer, characterized in that it sequentially has a rotation angle difference as much as the following conditional expression 1 and is configured to face different directions.
<Condition 1>
Rotation angle difference = 360°/ N
where N: number of guide bearings
According to claim 1,
The rotating rod is configured to have a long axis in a direction parallel to the rotational axis of the feeding gear, and the extruder for a 3D printer, characterized in that it is rotatably provided about a rotational axis parallel to the rotational axis of the feeding gear.
According to claim 1,
a support provided to protrude on the rotating rod; and a shaft mounted on the support and serving as a center of rotation of the guide bearing, wherein the guide bearing is freely rotatably mounted on the shaft.
According to claim 1,
The extruder for a 3D printer further comprising an elastic member for generating an elastic operation of the guide bearing when the guide bearing is in contact with the filament or is separated from the filament in contact.
A 3D printer capable of multi-color molding by selectively supplying a plurality of filaments, comprising: an extruder selectively transporting the plurality of filaments; a heat block that heats the filament selected by the extruder and transferred to a fluidized state; and a plurality of nozzles for injecting the filament fluidized by the heat block, wherein the extruder includes: a feeding gear provided to be axially rotatable and forcibly transporting the filament; a first driving unit for driving the feeding gear; a rotating rod provided to be axially rotatable; a guide bearing provided on the rotary rod and freely rotatable about a rotary shaft parallel to the rotary shaft of the feeding gear; and a second driving unit for generating an axial rotation of the rotating rod, wherein the guide bearings are provided with a plurality of spaced apart from each other along the longitudinal direction of the rotating rod, and the plurality of guide bearings are oriented in different directions. is provided, wherein the plurality of guide bearings are configured to selectively contact any one of the plurality of filaments from among the plurality of guide bearings according to the degree of axial rotation of the rotary rod by the second driving unit Color 3D printer.
7. The method of claim 6,
The distance between the centers of the nozzles is configured to be the same as the distance between the centers of the guide bearings, and the guide bearings are positioned vertically above the nozzles, respectively.

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