KR20210083803A - 3d printer for capable to discharge precise volume and controlling method thereof - Google Patents

Abstract

Disclosed is a 3D printer having improved mixing performance of a plurality of filaments by driving a screw and functions of retraction of an output material and preventing backward flow by driving the screw. In addition, disclosed is a 3D printer capable of precise output control by adjusting the distance between a nozzle part and a screw part depending on an output material. The 3D printer according to an embodiment of the present invention comprises: a heating part for forming a filament passage through which filament is supplied and providing heat to the filament; a nozzle part having a nozzle hole for outputting an output material in which the filaments are mixed; a filament supply part coupled to the heating part to supply the filaments to the nozzle part through the filament passage in the heating part; a screw part having at least a portion rotatably mounted to the nozzle hole of the nozzle part and the filament passage of the heating part to mix the filaments; and a driving part for rotating and driving the screw part to mix and output the filaments heated and melted by the heating part. The distance between the nozzle part and the screw part is adjustable.

Description

A 3D printer capable of quantitative dispensing and a control method therefor {3D PRINTER FOR CAPABLE TO DISCHARGE PRECISE VOLUME AND CONTROLLING METHOD THEREOF}

The present invention relates to a three-dimensional printer capable of quantitative ejection that outputs an output material by mixing a plurality of filaments, and more particularly, filament mixing performance and output quality can be improved by screw driving. , It relates to a 3D printer capable of quantitative ejection having a function of retraction of an output material by screw driving and a function of preventing backward flow in order to effectively remove residues from the 3D printing nozzle.

A 3D printer is a machine that creates 3D objects based on 3D drawings. 3D printers are divided into stacked type and cutting type according to the method of making three-dimensional printed matter. The stacking type is a method of stacking thin two-dimensional surfaces layer by layer, and the cutting type is a method of making prints by sculpting a large mass. In the case of the cutting type, material loss occurs because it is a method of cutting unnecessary parts of the material, but the stacked type does not lose material, so most recent 3D printers are printers using the layered type. A general multilayer 3D printer prints a three-dimensional object using a plastic filament as a main material. As the use of 3D printers has become popular, there has been a demand for 3D printers that can output various colors of output, and a technology that melts and laminates filaments of various colors to produce 3D prints of various colors is used. .

The conventional 3D printer of a method of melting and stacking a plurality of filaments is difficult to implement a desired color because the filaments are not output in a well mixed state, and there is a problem in that it is difficult to quantitatively control the output amount of the output material in which the filaments are mixed. In addition, in the conventional 3D printer, the heated/melted filament may flow back to the upper part of the nozzle by the pressure to which the filament is supplied, and the output amount of the filament decreases due to the reverse flow of the filament and the quality of the 3D output is deteriorated may result in

Conventional 3D printers generally use an extruder method that extrudes materials by pushing or pulling filaments directly. In this structure, even if the filament is retracted backwards to reduce nozzle residues during movement, the melt-extruded pressure at the tip of the nozzle It is difficult to effectively reduce the output quality, resulting in nozzle residues.

In addition, when the conventional 3D printer stops the printing process of outputting and stacking the output material through the nozzle and moves to the next output position, the residue in the melt-extruded state inside the nozzle flows out through the nozzle hole. This may adversely affect the quality of the 3D print, and when the print material remaining in the nozzle hole flows out and hardens, when the printing operation is resumed, the print success rate is reduced by hitting the print.

In addition, if the output is discharged in a state where the space between the nozzle and the screw is not secured, in the case of a high-viscosity output, the output is stagnant or pushed back inside the nozzle, resulting in an error in the amount of output, as the material is not smoothly output, A situation that requires maintenance/repair work may occur due to the problem of nozzle hole clogging.

An object of the present invention is to provide a three-dimensional printer capable of discharging a predetermined quantity of material by means of a screw operation.

In addition, the present invention is a three-dimensional (3D) having a function of retraction and backward flow prevention of output materials by screw driving to effectively reduce nozzle residues that deteriorate the output quality in the section in which the material is not discharged during three-dimensional stacking. This is to provide a printer.

In addition, the present invention is to provide a three-dimensional printer with improved mixing performance of a plurality of filaments by driving a screw.

Another object of the present invention is to provide a three-dimensional printer capable of finely adjusting the distance between the nozzle and the screw.

The three-dimensional printer according to an aspect of an embodiment of the present invention, in a three-dimensional printer for outputting an output material obtained by heating and mixing at least one filament, a filament passage to which the filament is supplied is formed therein, and heat to the filament a heating unit that provides; a nozzle unit having a nozzle hole through which a plurality of filaments are mixed to output an output material; a filament supply unit coupled to the heating unit to supply the plurality of filaments to the nozzle unit through the filament passage in the heating unit; a screw part at least a portion of which is rotatably mounted to the nozzle hole of the nozzle part and the filament passage of the heating part so as to mix the plurality of filaments; and a driving unit for rotating and driving the screw unit to mix and output a plurality of filaments heated and melted by the heating unit, and may be formed such that a distance between the nozzle unit and the screw unit is adjustable.

In addition, the screw unit may include: a lower screw rotating by the driving unit to mix a plurality of heated and melted filaments to output the output material or to retract the output material; and an upper screw provided on the lower screw and rotated by the driving unit.

In addition, the upper screw and the lower screw may have different diameters, and the upper screw and the lower screw may have different pitch lengths.

In addition, one end of the upper screw is connected to the driving unit, the other end is connected to the lower screw, the diameters of one end and the other end of the upper screw are the same, and one end of the lower screw is connected to the other end of the upper screw. The diameter of one end of the lower screw and the diameter of the other end of the upper screw may be the same as each other, and the lower screw may be formed such that the diameter decreases from one end to the other end.

In addition, the nozzle part surrounds a part of the lower screw, and a material flow space in which a part of the lower screw is accommodated and rotated is formed in the nozzle part, and the material flow space is moved from one side of the nozzle part to the other side of the nozzle part. The diameter may be continuously reduced as it goes, and the inner surface of the nozzle part and the spiral of the lower screw may be formed to be spaced apart from each other.

In addition, the inner surface of the nozzle part and the outer surface of the lower screw may be formed to be parallel to each other.

In addition, further comprising an upper body having a screw accommodation space to which the upper screw is mounted, the heating unit, the heating element is disposed therein, the heating unit body in which the filament passage is formed, the lower side of the heating unit body It is formed to protrude downward and may include a nozzle insertion part into which a part of the nozzle part is inserted, and an upper body insertion part formed on the upper side of the heating part body and recessed so that a part of the upper body is inserted.

In addition, the nozzle part includes a nozzle part body which is partially inserted into the nozzle insertion part and has a nozzle hole communicating with the material flow space at a lower end thereof, and is formed on an outer circumferential surface of the nozzle part body and is a part of the nozzle part body. includes a nozzle protrusion contacting an end of the nozzle inserting part in a state inserted into the nozzle inserting part, and the thickness of a portion of the nozzle part body inserted into the nozzle inserting part is formed to continuously decrease from the lower side to the upper side can be

In addition, the nozzle part is movable in a vertical direction while being inserted into the nozzle inserting part of the heating part, and by the interference between the nozzle protrusion part and the nozzle inserting part, the movement of the nozzle part with respect to the heating part may be restricted. have.

In addition, the nozzle unit body is connected to the filament passage and is formed with a nozzle portion insertion space into which the nozzle protrusion is inserted, the diameter of the nozzle portion insertion space may be formed larger than the diameter of the filament passage.

In addition, the upper body includes an upper body body having the screw accommodating space formed therein, and an upper body protrusion formed under the upper body body and inserted into the upper body insertion part, and the screw accommodating space includes A depression stopper portion is formed to be depressed toward the upper body body side, a shaft unit in which a spiral is not formed is formed on an upper side of the upper screw portion, and the shaft unit includes a screw protrusion unit that is rotatably fitted to the stopper portion. can be

In addition, the upper body side threaded portion is formed on the outer circumferential surface of the upper body protrusion, and the upper body side screw portion is formed on the inner circumferential surface of the upper body insertion portion to be screwed with the upper body side screw portion, the heating unit and the When any one of the upper body is rotated in the first direction, a distance between the lower screw rotatably connected to the upper body and the nozzle unit fixed to the heating unit increases, and one of the heating unit and the upper body increases. When any one is rotated in a second direction different from the first direction, the distance between the lower screw and the nozzle part may be reduced.

In addition, the upper body is formed with a gas outlet for discharging gas generated in the process of heating and melting the filament by the heating unit, the gas outlet is the upper portion to communicate with the screw receiving space and the filament passage At least one of an air-cooled cooling fin for cooling the upper body and a cooling passage through which the cooling water flows is formed on the rear side of the upper screw so that the filament heated and melted by the heating unit does not flow backward. can

In addition, the driving unit may rotate the screw unit in a first direction to quantitatively output the output material through the nozzle hole by mixing the plurality of heated and melted filaments during a printing operation for outputting the output material; In a state in which the printing operation is stopped, the screw unit may be configured to rotate in a second direction opposite to the first direction to retract the output material remaining in the nozzle hole to the rear.

In addition, based on the viscosity of the melted filament, it is characterized in that the distance between the nozzle part and the screw part is adjusted, and when the viscosity of the filament is high, the distance between the nozzle part and the screw part is, When the viscosity of the filament is small, it may be formed to be larger than a gap between the nozzle part and the screw part.

In addition, the viscosity of the filament may include viscosity information input by the user.

In addition, the viscosity of the filament is calculated based on the amount of torque applied to rotate the screw when the driving unit rotates the screw unit, and the first filament required to rotate the screw unit in the state in which the first filament is inserted. When the magnitude of the torque is greater than the magnitude of the second torque required to rotate the screw part in a state in which the second filament is input, the viscosity of the first filament may be determined to be greater than the viscosity of the second filament.

According to an embodiment of the present invention, the present invention provides a three-dimensional printer with improved mixing performance of a plurality of filaments by driving a screw.

In addition, according to an embodiment of the present invention, there is provided a three-dimensional printer having functions of retraction of an output material and preventing backward flow by screw driving.

In addition, according to an embodiment of the present invention, a three-dimensional printer capable of precisely controlling the output of an output material by finely adjusting the distance between the nozzle and the screw is provided.

1 is a view showing a 3D printer according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of the 3D printer of FIG. 1 .
FIG. 3 is a view showing an enlarged state of a part of the 3D printer of FIG. 2 .
FIG. 4 is a diagram illustrating a process in which a nozzle unit of the 3D printer of FIG. 1 is moved.
FIG. 5 is a flowchart illustrating a control method of the 3D printer of FIG. 1 .
6 is a view showing a process in which the upper body and the screw part are moved in the 3D printer according to another embodiment of the present invention.
FIG. 7 is a view showing an enlarged state of a part of the 3D printer of FIG. 6 .

Hereinafter, the technical idea of the present invention will be described in more detail with reference to the accompanying drawings. Prior to this, the terms or words used in the present specification and claims should not be construed as being limited to conventional or dictionary meanings, and the inventor should properly understand the concept of the term in order to best describe his invention. Based on the principle that it can be defined, it should be interpreted as meaning and concept consistent with the technical idea of the present invention.

Hereinafter, the technical idea of the present invention will be described in more detail with reference to the accompanying drawings. Since the accompanying drawings are merely examples shown to explain the technical idea of the present invention in more detail, the technical idea of the present invention is not limited to the form of the accompanying drawings. The embodiments described in the present specification and the configurations shown in the drawings are only the most preferred embodiment of the present invention, and do not represent all the technical spirit of the present invention, so various modifications that can be substituted for them at the time of the present application It should be understood that there may be examples.

1 is a view showing a 3D printer according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the 3D printer of FIG. 1 . And, FIG. 3 is a view showing an enlarged state of a part (part III) of the 3D printer of FIG. 2 .

1 to 3 , the 3D printer according to an embodiment of the present invention may output by heating and mixing a plurality of filaments, which are output materials. The three-dimensional printer 1 according to an embodiment of the present invention includes a nozzle unit 10, a filament supply unit 20, a filament supply pipe 30, a screw unit 40, a driving unit 50, an upper body 60, and heating. The unit 70, the XYZ driving unit (not shown) for moving the bed unit (not shown) and the bed unit and/or the nozzle unit 10 from which the output is output, and a control unit (not shown) for controlling the components ) is included.

In more detail, the nozzle unit 10 may include a nozzle hole 12 for outputting a mixed output material by heating and melting a plurality of filaments 22 . The nozzle hole 12 may be formed in the center of the nozzle part 10 in the longitudinal direction of the screw part 40 . The nozzle unit 10 may be mounted on a lower portion of the heating unit 70 coupled to the lower portion of the upper body 60 .

The heating unit 70 includes heating elements for heating the filament 22 supplied to the nozzle unit 10, and the heating elements may be heating elements heated by electricity. However, the heating method by the heating elements is not limited to the electric heating method. The heating unit 70 may be exemplarily formed of a metal material for smoothly transferring heat. In the center of the heating unit 70 , a filament passage 77 communicating with the nozzle hole 12 of the nozzle unit 10 may be formed in the longitudinal direction of the screw unit 40 . The filament passage 77 is communicated with the filament supply pipe 30 , and a plurality of filaments 22 supplied by the filament supply unit 20 may be introduced into the filament passage 77 . In order to prevent backward flow of the output material, the filament passage 77 into which the upper part having the expanded diameter of the screw part 40 is inserted is the nozzle hole 12 into which the lower part having the reduced diameter of the screw part 40 is inserted. It may be formed to have a larger diameter.

One side of the heating unit 70 communicates along the circumference of the filament passage 77 , and the other side thereof may have a plurality of filament supply holes 76 communicating with the filament supply pipe 30 . The filament supply hole 76 may be formed in a downwardly inclined direction from the outer periphery of the heating unit 70 toward the center so that the filament 22 can be stably supplied to the filament passage 77 . That is, the filament 22 supplied from the filament supply pipe 30 toward the filament passage 77 is supplied toward the nozzle unit 10 in a direction inclined with respect to the extension direction of the screw unit 40 .

In the embodiment, the filament supply hole 76 is within the range of about 10 to 80° with respect to the arrangement direction (up and down direction Z) of the screw part 40 in order to stably supply the filament and prevent interference with the upper body 60 . It may be formed to be inclined to have an angle, but the angle of the filament supply hole 76 is not limited thereto.

The filament supply unit 20 may supply a plurality of filaments 22 to the filament passage 77 through the filament supply hole 76 . The plurality of filaments 22 may be filaments of different colors or may be filaments of different types. Filament 22 is a plastic material such as ABS (Acrylonitrile Butadiene Styrene), PLA (PolyLactic Acid), thermoplastic urethane (TPU; Thermoplastic Poly Urethane), elastomer (TPE; Thermo Plastic Elastomer), PP (Poly Propylene), PET (Poly Propylene) Ethylene Terephthalate) may be included as a main material, but is not limited thereto.

The filament supply unit 20 may include a plurality of filament supply modules (not shown) mounted on the heating unit 70 in a form symmetrical about the screw unit 40 . The filament supply module may supply the filament 22 to the filament passage 77 in the heating unit 70 by pushing the filament 22 wound around the filament winding unit (reference numeral omitted). The filament supply module may include a roller for pushing the filament 22 and a supply motor (not shown), but is not limited thereto. In addition, although the filament supply unit 20 has been described as being symmetrically formed around the screw unit 40 , only one filament supply unit 20 supplies the filament to the screw unit 40 side, or a plurality of A configuration in which the filament supply unit 20 is arranged in an eccentric position without being symmetrical to each other is also included in the embodiment of the present invention.

In the illustrated embodiment, the 3D printer includes the filament supply module, and is configured to output an output material by heating, melting, and mixing two filaments 22, but by mixing three or more filaments 22 It may be configured to output an output material. The three-dimensional printer can output various colors of output materials by adjusting the color, type, supply speed, supply amount, etc. of the plurality of filaments 22 .

One side of the filament supply pipe 30 is connected to the filament supply unit 20 and the other side is connected to the heating unit 70 , and the filament supply pipe 30 is a plurality of filaments supplied to the filament passage 77 in the heating unit 70 . (22) provides space for movement. At least a portion of the filament supply pipe 30 is inserted into the heating unit 70 side, and in the process of the heating unit 70 performing a heating operation, one side of the filament supply pipe 30 is at a temperature close to room temperature, and the filament supply pipe 30 ) The temperature of the other side may be close to the melting temperature of the filament.

The screw part 40 may have a lower end rotatable within the heating unit 70 and the nozzle unit 10 , and an upper end may be mounted on the upper body 60 .

The upper end of the screw unit 40 may be rotatably mounted to the upper body 60 in a forward/reverse direction through a support means such as a bearing (not shown). The screw unit 40 may mix a plurality of filaments 22 heated and melted by the heating unit 70 when rotated in the forward direction by the driving unit 50 . The output material in which the plurality of filaments 22 are mixed by the screw unit 40 may be output through the nozzle unit 10 .

The screw unit 40 may have a retraction function to recover the output material to the rear side when rotating in the reverse direction (a function to pull the output material backward when the discharge of the output material is temporarily stopped during the 3D printing process). . In addition, the screw unit 40 can prevent the output material mixed by melting the plurality of filaments 22 due to the supply pressure of the filaments 22 from flowing backward toward the upper body 60 .

The driving unit 50 may rotate the screw unit 40 in a forward/reverse direction. The driving unit 50 may be mounted on the upper body 60 . The driving unit 50 may be provided as a driving motor 52 , a hydraulic cylinder, or the like, but as long as it can rotate the screw unit 40 , it may be used without particular limitation.

In an embodiment, the driving unit 50 may provide a first driving mode and a second driving mode. In the first driving mode, the screw unit 40 is rotated in the first direction (forward direction) during the printing operation for outputting the output material to mix a plurality of filaments 22 to output the output material through the nozzle hole 12, , is a mode for quantitatively controlling the discharge amount of the output material. It is also possible to control the discharge amount of the output material by controlling the rotation speed of the screw unit 40 by the driving unit 50 in the first driving mode.

In the second driving mode, in a state in which the output of the output material through the nozzle unit 10 is stopped (printing stop mode), the screw unit 40 is driven by the driving unit 50 in a second direction opposite to the first direction. It is a mode in which the output material can be retracted backward (upper) toward the upper region of the screw portion 40 by the screw portion 40 by rotationally driving (reverse direction).

In one embodiment, the screw part 40 may include a lower screw 42 and an upper screw 44 . The lower screw 42 for effectively reducing the discharge pressure of the material to prevent the nozzle residue from coming out may be installed in the heating unit 70 and the nozzle unit 10 .

In one embodiment, the lower screw 42 and the upper screw 44 may be integrally formed to be coaxial. The driving unit 50 may include a driving shaft 54 connected to the driving motor 52 and rotationally driven by the driving motor 52 . The lower screw 42 is rotated in the forward/reverse direction by the driving unit 50 to mix the plurality of filaments 22 or to retract the output material.

The lower screw 42 may have a fine distance (eg, greater than 0, less than 1 mm spacing) from the inner wall surface of the nozzle unit 10 . By forming a very small gap between the lower screw 42 and the inner wall surface of the nozzle unit 10, the space inside the nozzle unit 10 can be minimized, the retraction effect is improved, and the discharge speed of the output material is increased. can do it

The upper screw 44 is provided on the upper part of the lower screw 42, and can prevent the backward flow of the output material. In the embodiment, the upper screw 44 and the lower screw 42 have different pitch lengths to prevent backward flow of the output material, and the diameters of the upper screw 44 and the lower screw 42 are different from each other. can be formed. In one embodiment, the upper screw 44 has a pitch length P2 greater than the pitch length P1 of the lower screw 42, and a diameter D2 greater than the diameter D1 of the lower screw 42. ) can have And, the lower screw 42 may be formed in a shape in which the diameter is continuously increased from the end toward the upper screw 44 side, and the diameter of the upper screw 44 is formed constant. At this time, the maximum diameter of the lower screw 42 may be formed larger than the diameter of the upper screw 44 , and the minimum diameter of the lower screw 42 may be formed smaller than the diameter of the upper screw 44 .

In one embodiment, one end of the upper screw 44 is connected to the driving unit 50, the other end is connected to the lower screw 42, and the diameter of one end and the other end of the upper screw 44 may be the same as each other. have.

One end of the lower screw 42 is connected to the other end of the upper screw 44 , and the diameter of one end of the lower screw 42 and the diameter of the other end of the upper screw 44 may be identical to each other.

The lower screw 42 may be formed such that its diameter decreases from one end to the other. That is, as the diameter of the lower screw 42 decreases, the output material can be finely adjusted so that the output material is constantly output from the upper screw 44 and then an appropriate output amount is output from the lower screw 42 .

In one embodiment, the driving unit 50 may drive the lower screw 42 and the upper screw 44 at the same rotational speed. In this case, it is possible to prevent the output material from flowing backward toward the upper body 60 by pushing the output material downward by the strong rotational force of the upper screw 44 having a relatively large pitch interval and diameter.

In another embodiment not shown, the driving unit 50 may drive the lower screw 42 and the upper screw 44 at different rotational speeds. For example, the driving unit 50 may include a first driving unit for rotationally driving the lower screw 42 and a second driving unit for driving the upper screw 44 , and the lower part by the first driving unit and the second driving unit The rotation speed of the screw 42 and the upper screw 44 may be different.

For example, by increasing the rotational speed of the upper screw 44 by the second driving unit higher than the rotational speed of the lower screw 42, it is possible to increase the backflow prevention performance of the output material. In this case, the upper screw 44 may be provided to have the same pitch length and the same diameter as the lower screw 42 .

In one embodiment, the driving unit 50 mixes the plurality of heated and melted filaments 22 during the printing operation for outputting the output material, and the screw unit 40 to output the output material through the nozzle hole 12 . ) may be rotationally driven in the first direction.

In a state in which the printing operation is stopped, the nozzle hole 12 may be formed to rotate the screw unit 40 in a second direction opposite to the first direction to retract the remaining output material to the rear. In one embodiment, the upper body 60 to which the upper screw 44 is mounted has a gas outlet 64 for discharging gas generated in the process of melting the filament 22 by the heating unit 70 , the upper body It may be formed to communicate with the filament passage 77 of the screw accommodating space 65 and the heating unit 70 in the 60 . A cleaning tool may be introduced into the gas outlet 64 during a cleaning operation.

In one embodiment, the upper body 60 is cooled on the rear (upper) side of the upper screw 44 so that the filament 22 melted by the heating unit 70 does not flow backward toward the upper body 60 . An air-cooled cooling fin 66 and a cooling passage 68 through which cooling water flows may be formed. The cooling water may be introduced through the cooling water inlet and may be discharged through the cooling water outlet after moving along the cooling passage 68 . The filament 22 melted by the heating unit 70 by maintaining the temperature of the upper body 60 side by the air-cooled cooling fin 66 and the cooling flow path 68 at a temperature such that the filament 22 does not melt. ) can be suppressed from being drawn in backwards. According to the embodiment of the present invention, a plurality of filaments 22 in the nozzle unit 10 are uniformly mixed by the screw unit 40 rotating in the forward direction within the nozzle unit 10 and output from the nozzle unit 10 . and can maintain a constant supply pressure of the output material. In addition, according to an embodiment of the present invention, when the 3D printing process is stopped, the retraction of the output material is possible by the reverse driving of the screw unit 40 .

In addition, according to the embodiment of the present invention, it is possible to supply a driving force to the lower screw 42 by rotating the upper screw 44 having a larger pitch length and diameter than the lower screw 42 , and the lower screw 42 . When some output material is introduced into the upper screw 44 side by the pressure of the filament 22 supplied to the side, the output material is pushed downward toward the nozzle unit 10 with the strong rotational force of the upper screw 44. Backflow of material can be prevented.

According to the embodiment of the present invention, a plurality of filaments 22 can be smoothly mixed by the screw unit 40 , and a desired color can be accurately realized by outputting an output material in which the plurality of filaments 22 are uniformly mixed. It is possible to quantitatively control the output amount of the output material to improve the quality of the 3D output.

In addition, according to the embodiment of the present invention, by pushing the output material downward with a strong force by the upper screw 44 , the output material is rearward by the pressure supplied to the filament passage 77 by the plurality of filaments 22 . It is possible to prevent the backflow of the output material, and it is possible to improve the quality of the 3D output by suppressing the backward flow of the output material. That is, since the upper screw 44 has a larger diameter than the lower screw 42, when the upper screw 44 and the lower screw 42 are rotated at the same number of revolutions, the pitch formed on the outer peripheral surface of the upper screw 44 A larger torque is applied to the output material moving forward along the ?, compared to the output material partially moved backward by the pitch formed on the outer peripheral surface of the lower screw 42 .

In addition, according to the embodiment of the present invention, when the printing process of outputting and stacking the output material through the nozzle unit 10 is temporarily stopped, the remaining in the nozzle hole 12 due to the reverse rotation of the screw unit 40 . It is possible to retract the output material to the rear. Therefore, it is possible to prevent the output material remaining in the nozzle hole 12 from being output at the time of stopping the printing and adversely affecting the quality of the three-dimensional output, and output through the nozzle part 10 due to the nozzle hole 12 clogging It is possible to prevent the material from being output smoothly.

In addition, according to the embodiment of the present invention, the nozzle part 10 surrounds a part of the lower screw 42 , and a part of the lower screw 42 is accommodated and rotated in the nozzle part 10 in the material flow space 73 . ) can be formed. The material flow space 73 continuously decreases in diameter from one side of the nozzle unit 10 to the other side of the nozzle unit 10, and the inner surface of the nozzle unit 10 and the spiral of the lower screw 42 are spaced apart from each other. It may be formed so as to maintain an established state.

In addition, according to the embodiment of the present invention, the inner surface of the nozzle unit 10 and the outer surface of the lower screw 42 may be formed to be parallel to each other. At this time, the inner surface of the nozzle unit 10 and the lower screw 42 are spaced apart from each other at a predetermined distance and maintained in parallel to prevent friction between the inner surface of the nozzle unit 10 and the lower screw 42 and the output material flows stably. There are advantages to doing.

In addition, according to an embodiment of the present invention, the heating unit 70 has the heating element disposed therein and the heating unit body 71 having a filament passage 77 formed therein, and the lower side of the heating unit body 71 . The nozzle insertion part 72 is formed to protrude downward and a part of the nozzle part 10 is inserted, and the upper body formed on the upper side of the heating part body 71 and recessed so that a part of the upper body 60 is inserted. It may include an insert 74 . There is an effect that the heating unit 70 can be more stably and firmly coupled to the nozzle unit 10 and the upper body 60 by the nozzle insertion unit 72 and the upper body insertion unit 74 .

In addition, the upper body 60 includes an upper body body 61 having a screw accommodating space 65 formed therein, and an upper body protrusion formed under the upper body body 61 and inserted into the upper body insertion part ( 62).

In addition, a depression stopper portion 63 that is depressed toward the upper body body 61 side may be formed in the screw accommodating space 65 , and a shaft unit 45 in which a spiral is not formed on the upper side of the upper screw 44 . ) is formed, and the shaft unit 45 includes a screw protrusion unit 48 that is rotatably fitted to the depression stopper part 63 . In this embodiment, the screw protrusion unit 48 of the screw part 40 is fitted into the depression stopper part 63 of the upper body 60 , and the screw part 40 is fixed in position relative to the upper body 60 . In addition, according to the embodiment of the present invention, the nozzle unit 10 is partially inserted into the nozzle insertion unit 72 and communicated with the material flow space 73 at the lower end thereof. The nozzle unit body 11 in which a nozzle hole (not shown) is formed, and the nozzle unit body 11 is formed on the outer peripheral surface of the nozzle unit body 11, and the nozzle is inserted in a state in which a part of the nozzle body 11 is inserted into the nozzle insertion unit 72 . It may include a nozzle protrusion 13 in contact with the end of the portion 72 .

The thickness of a portion of the nozzle unit body 11 inserted into the nozzle insertion unit 72 may be continuously reduced from the lower side to the upper side.

Meanwhile, according to an embodiment of the present invention, the distance between the screw part 40 and the inner surface of the nozzle part 10 may be adjusted according to the viscosity of the input filament. Hereinafter, a configuration in which the distance between the screw part 40 and the inner surface of the nozzle part 10 is adjusted in the embodiment of the present invention will be described in detail.

FIG. 4 is a diagram illustrating a process in which a nozzle unit of the 3D printer of FIG. 1 is moved.

Referring to FIG. 4 , the nozzle unit 10 of the 3D printer according to the present embodiment is moved relative to the heating unit 70 , so that the distance between the inner surface of the nozzle unit 10 and the screw unit 40 is reduced. to be adjusted.

In more detail, the nozzle unit 10 is formed to be movable in the vertical direction while being inserted into the nozzle insertion unit 72 of the heating unit 70 . And, by the interference between the nozzle protrusion part 13 and the nozzle insertion part 72, the movement of the nozzle part 10 with respect to the heating part 70 is restricted.

In addition, the nozzle unit body 11 may be connected to the filament passage 77 and the nozzle unit insertion space 75 into which the nozzle protrusion 13 is inserted may be formed. A diameter of the nozzle insertion space 75 may be larger than a diameter of the filament passage 77 .

In this embodiment, by adjusting the clearance between the lower screw 42 and the nozzle part 10 to secure a space, the viscosity control range of the output material can be adjusted from low viscosity to high viscosity without separately replacing the screw. It also has the advantage of improving the output quality and productivity by discharging the output of the printer constantly without clogging. That is, the interval between the nozzle part 10 and the screw part 40 when the viscosity of the filament 22 is large is between the nozzle part 10 and the screw part 40 when the viscosity of the filament 22 is small. By being formed larger than the interval of, it is possible to respond to the filaments 22 of various viscosities.

In addition, according to the embodiment of the present invention, based on the viscosity of the molten filament 22, the distance between the nozzle unit 10 and the screw unit 40 may be adjusted.

That is, for example, when the filament 22 is put into the 3D printer, the user inputs the viscosity information of the filament 22 to the control unit, and the control unit is a lower screw according to the viscosity information of the input filament 22 . The distance between 42 and the nozzle part 10 can be controlled. According to this embodiment, the space between the lower screw 42 and the nozzle part 10 is secured, so that even high-viscosity output materials are constant without clogging. It has the advantage that it can be easily retracted to the inside of the nozzle by pressure according to the volume change.

On the other hand, according to another embodiment of the present invention, the viscosity of the filament 22, when the driving unit 50 rotates the screw unit 40, based on the magnitude of the torque input to rotate the screw unit 40 can be calculated.

That is, the control unit of the three-dimensional printer according to an embodiment of the present invention determines the magnitude of the first torque required to rotate the screw unit 40 in a state in which the first filament having a specific viscosity is input with the first filament. When the second filament having a different viscosity is greater than the magnitude of the second torque required for rotation of the screw unit 40 in the input state, the viscosity of the first filament may be determined to be greater than that of the second filament. . In this case, the control unit may calculate the torque based on the magnitude of the current or voltage supplied to the driving unit 50 .

Therefore, by automatically determining the viscosity of the filament based on the amount of power required to rotate the screw unit 40, even when filaments having different viscosities are continuously input, the three-dimensional printer determines the viscosity of the filament. There is an advantage in that the interval between the screw part 40 and the nozzle part 10 can be adjusted based on this.

Hereinafter, the control method of the 3D printer according to the present embodiment will be described in more detail.

5 is a flowchart illustrating a method for controlling a 3D printer according to an embodiment of the present invention.

Referring to FIG. 5 , the viscosity of the output material is determined ( S110 ). At this time, the viscosity of the filament 22, in one embodiment, may include the viscosity information input by the user. In addition, according to another embodiment of the present invention, the viscosity of the filament 22 is based on the size of the power required to rotate the screw unit 40 when the driving unit 50 rotates the screw unit 40 . can be calculated. That is, when the size of the first power required to rotate the screw unit 40 in the state in which the first filament is input is greater than the size of the second power required to rotate the screw unit 40 in the state in which the second filament is input , The viscosity of the first filament may be determined to be greater than the viscosity of the second filament.

Then, an output mode is selected (S120). At this time, based on the viscosity of the molten filament, the distance between the nozzle unit 10 and the screw unit 40 may be adjusted. That is, the interval between the nozzle part 10 and the screw part 40 when the viscosity of the filament 22 is large is between the nozzle part 10 and the screw part 40 when the viscosity of the filament 22 is small. can be adjusted to be larger than the interval of

On the other hand, after performing the output (S130), when it is determined that the output is normally performed, the output is terminated (S140), and when it is determined that the output is not performed (S141), the output is performed again (S130).

In addition, according to the embodiment of the present invention, by the screw unit 40, a function of mixing a plurality of heated and molten filaments 22 during printing, a function of preventing backward flow of the output material, and printing It is possible to implement all functions of retraction of the output material during interruption, simplifying and lightening the 3D printer, reducing manufacturing cost by making it with a compact structure, and convenience in storage and use of the 3D printer can enhance

6 is a view showing a process in which the upper body and the screw part are moved in the 3D printer according to another embodiment of the present invention, and FIG. 7 is a view showing an enlarged state of a part (part VII) of the 3D printer of FIG. 6 to be.

This embodiment has only a difference in the configuration in which the upper body and the screw part are relatively moved, and in other configurations, it is the same as the configuration of the 3D printer shown in FIGS. 1 to 5 . Hereinafter, the characteristic parts of this embodiment will be explained based on

6 and 7, according to the embodiment of the present invention, the upper body 60 disposed on the upper side of the heating unit 70 in a state where the position of the heating unit 70 is fixed is the heating unit (70) By moving upward or downward with respect to the upper body 60, the distance between the screw part 40 and the nozzle part 10 connected to the upper body 60 can be adjusted.

In more detail, an upper body side screw portion 69 in which a spiral is formed may be formed on the outer circumferential surface of the upper body protrusion portion 62 . An inner peripheral surface of the upper body insertion part 74 may be formed with a heating part-side threaded part 79 that is screwed with the upper body-side threaded part 69 .

At this time, when any one of the heating unit 70 and the upper body 60 is rotated in the first direction, it is fixed to the lower screw 42 rotatably connected to the upper body 60 and the heating unit 70 . The distance between the nozzle units 10 is formed to increase.

Conversely, when any one of the heating unit 70 and the upper body 60 is rotated in a second direction different from the first direction, the distance between the lower screw 42 and the nozzle unit 10 is reduced. .

That is, by rotating the upper body 60 in the first direction or the second direction relative to the heating unit 70, the upper body 60 is moved upward or downward with respect to the heating unit 70, The relative distance between the screw part 40 rotatably connected to the upper body 60 and the nozzle part 10 may be adjusted.

In this embodiment, the upper body 60 is screwed with the heating unit 70, and the upper body 60 can move relative to the heating unit 70 in a state where airtightness is maintained by the screw coupling. There are advantages.

In this embodiment, although the upper body 60 is described as being rotated, the upper body 60 is slidably coupled with respect to the heating unit 70 , and the upper body 60 is slidably coupled to the heating unit 70 . A configuration that can be moved by sliding is also included in the embodiment of the present invention. And, the upper body 60 includes a separate distance adjusting means that can be rotated independently of the upper body body 61, the distance adjusting means is rotated in a screwed state with the heating unit 70, the upper A configuration for moving the body 60 upward or downward with respect to the heating unit 70 is also included in the embodiment of the present invention.

In the illustrated embodiment, the screw part 40 is a screw of a two-stage structure consisting of an upper screw 44 and a lower screw 42, but the screw part 40 is made of a single screw, or diameter, pitch And/or it may be composed of a screw having three or more stages of which the rotation speed is changed. The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention as claimed in the claims.

10: nozzle
12: nozzle ball
20: filament supply unit
22: filament
28: supply motor
30: filament supply pipe
40: screw part
42: lower screw
44: upper screw
45: shaft unit
48: screw protrusion unit
50: drive unit
52: drive motor
60: upper body
61: upper body body
62: upper body protrusion
63: depression stopper part
65: screw receiving space
64: gas outlet
66: air cooling cooling fins
68: cooling flow path
69: upper body side screw part
70: heating unit
71: heating unit body
72: nozzle insert
73: material flow space
74: upper body insertion part
76: filament supply hole
77: filament passage
79: heating part side screw part

Claims (17)

In a three-dimensional printer for outputting an output material obtained by heating and mixing at least one filament,
A filament passage through which the filament is supplied is formed therein, the heating unit for providing heat to the filament;
a nozzle unit having a nozzle hole through which a plurality of filaments are mixed to output an output material;
a filament supply unit coupled to the heating unit to supply the plurality of filaments to the nozzle unit through the filament passage in the heating unit;
a screw part at least a portion of which is rotatably mounted to the nozzle hole of the nozzle part and the filament passage of the heating part so as to mix the plurality of filaments;
Includes; a driving unit for rotating the screw unit so as to mix and output a plurality of filaments heated and melted by the heating unit;
3D printer, characterized in that the distance between the nozzle part and the screw part is adjustable. According to claim 1,
The screw part,
a lower screw rotating by the driving unit to mix the plurality of heated and melted filaments to output the output material or to retract the output material; and
A 3D printer comprising an upper screw provided on the lower screw and rotated by the driving unit. 3. The method of claim 2,
The upper screw and the lower screw have different diameters, and the upper screw and the lower screw have different pitch lengths. 4. The method of claim 3,
One end of the upper screw is connected to the driving unit, the other end is connected to the lower screw, and the diameters of one end and the other end of the upper screw are the same,
One end of the lower screw is connected to the other end of the upper screw, and the diameter of one end of the lower screw and the diameter of the other end of the upper screw are the same,
The lower screw is a 3D printer, characterized in that the diameter decreases from one end to the other end. According to claim 1,
The nozzle part surrounds a part of the lower screw, and a material flow space in which a part of the lower screw is accommodated and rotated is formed in the nozzle part,
The material flow space is continuously reduced in diameter from one side of the nozzle part toward the other side of the nozzle part,
The three-dimensional printer, characterized in that the inner surface of the nozzle part and the spiral of the lower screw are maintained spaced apart from each other. 6. The method of claim 5,
3D printer, characterized in that the inner surface of the nozzle part and the outer surface of the lower screw are parallel to each other. According to claim 1,
Further comprising an upper body having a screw receiving space in which the upper screw is mounted,
The heating unit includes a heating element having a heating element disposed therein and having the filament passage formed therein, and a nozzle insertion unit protruding downwardly below the heating unit body and into which a part of the nozzle unit is inserted, and the heating unit. A three-dimensional printer including an upper body insert formed on the upper side of the sub body and recessed so that a part of the upper body is inserted. 8. The method of claim 7,
The nozzle part includes a nozzle part body which is partially inserted into the nozzle insertion part and has a nozzle hole communicating with the material flow space at a lower end thereof, and is formed on an outer circumferential surface of the nozzle part body, and a part of the nozzle part body is and a nozzle protrusion in contact with the end of the nozzle inserting part in a state inserted into the nozzle inserting part,
The thickness of a portion of the body of the nozzle unit inserted into the nozzle insertion unit is continuously reduced from the lower side to the upper side. 9. The method of claim 8,
The nozzle part is movable in the vertical direction in a state inserted into the nozzle insertion part of the heating part,
The three-dimensional printer, characterized in that by the interference between the nozzle protrusion and the nozzle insertion part, the movement of the nozzle part with respect to the heating part is limited. 9. The method of claim 8,
The nozzle body is connected to the filament passage and the nozzle portion insertion space into which the nozzle protrusion is inserted is formed, and the diameter of the nozzle portion insertion space is larger than the diameter of the filament passage. 8. The method of claim 7,
The upper body includes an upper body body having the screw receiving space therein, and an upper body protrusion formed below the upper body body and inserted into the upper body insertion part,
A depression stopper that is depressed toward the upper body body is formed in the screw receiving space,
A three-dimensional printer, characterized in that the shaft unit is formed on the upper side of the upper screw is not formed, the shaft unit is a screw protrusion unit that is rotatably fitted to the stopper portion is formed. 12. The method of claim 11,
An upper body side screw portion in which a spiral is formed is formed on the outer circumferential surface of the upper body protrusion,
On the inner peripheral surface of the upper body insertion part, a heating part side threaded portion screwed with the upper body side thread part is formed,
When any one of the heating unit and the upper body is rotated in the first direction, the distance between the lower screw rotatably connected to the upper body and the nozzle unit fixed to the heating unit increases,
When any one of the heating unit and the upper body is rotated in a second direction different from the first direction, a distance between the lower screw and the nozzle unit is reduced. 8. The method of claim 7,
The upper body is formed with a gas outlet for discharging gas generated in the process of heating and melting the filament by the heating unit,
The gas outlet is formed in the upper body to communicate with the screw receiving space and the filament passage,
At least one of an air-cooled cooling fin for cooling the upper body and a cooling passage through which coolant flows is formed on the rear side of the upper screw so that the filament heated and melted by the heating unit does not flow backward. According to claim 1,
The drive unit,
driving the screw unit to rotate in a first direction to quantitatively output the output material through the nozzle hole by mixing the plurality of heated and melted filaments during a printing operation for outputting the output material;
The 3D printer is configured to rotate the screw unit in a second direction opposite to the first direction to retract the output material remaining in the nozzle hole to the rear in a state in which the printing operation is stopped. According to claim 1,
Based on the viscosity of the melted filament, characterized in that the distance between the nozzle part and the screw part is adjusted,
The distance between the nozzle part and the screw part when the viscosity of the filament is high is greater than the distance between the nozzle part and the screw part when the viscosity of the filament is small. 16. The method of claim 15,
The viscosity of the filament is a three-dimensional printer, characterized in that the viscosity information input by the user. 16. The method of claim 15,
The viscosity of the filament is calculated based on the amount of torque applied to rotate the screw when the driving unit rotates the screw,
When the magnitude of the first torque required to rotate the screw part in the state in which the first filament is input is greater than the magnitude of the second torque required to rotate the screw part in the state in which the second filament is input, the viscosity of the first filament is 3D printer, characterized in that it is determined to be greater than the viscosity of the second filament.

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