KR20190067403A - 3D printing system - Google Patents

Abstract

The present invention provides a 3D printing system, wherein to reduce contraction stress of a structure printed by sintering metal powder that is a material, a plurality of heat sources are provided in a material storage unit and a working space for the material to be continuously maintained at a high temperature. Moreover, the working space is maintained at a high temperature, and further, to block contact between the material and oxygen, high temperature gas is sprayed to the working space, and the sprayed gas, metal fume scattering as melting the material with a laser, and by-products including smog are collected. Only gas is extracted from the by-products to be circulated into the working space again.

Description

3D printing system

The present invention relates to a 3D printing system, and more particularly, to a 3D printing system for printing a 3D sculpture by performing a process of sintering by laser irradiation while being laminated on a layer of metal powder as a material.

Generally, 3D printing technology is a manufacturing technology that produces articles in a three-dimensional space by using cross-sectional data of arbitrary objects to be formed based on a 3D stereoscopic drawing.

However, over the years, printer equipment and materials have been too expensive to be used for very limited applications. In the early stage of development, it was limited to plastic materials and used for limited purposes, but it has been applied to all industrial fields to the extent that nylon and metal etc. can be expanded to output cell phone cases and automobile accessories.

Metal 3D printers based on metal powders can be used as feeding means for supplying fine powder onto the platform, laser means for heating the powder on the platform to sinter or melting to form sculpture, And raising and lowering means.

In addition, there are SLP (PBF) method and DED (DMT) method in the printer method based on the metal powder, and the PBF (Powder bed fusion) method which fuses the flat powdered area with the selective thermal energy and the concentrated thermal energy There is a Directed Energy Deposition (DED) method that melts and deposits.

Such a PBF method is advantageous for achieving a relatively precise shape freely, while the DED method has a wide range of fabrication and a wide range of materials to be used.

In the DED method, the high-power laser beam is locally irradiated to form a molten pool on the surface of the base material, and the metal powder supplied in real time through the coaxial powder feeder is melted and rapidly solidified to form a metal layer having a dense structure. In this case, powder gas and coaxial gas are supplied to prevent transfer and oxidation of metal powder.

Such a conventional technique can be confirmed in Published Patent No. 10-2017-0014618 (Feb.

The conventional SLS type 3D printer includes a housing frame in which an interior is formed as a work space, a molding chamber that forms a molding space of an arbitrary shape in a work space of the housing frame, A laser apparatus for sintering a region corresponding to cross-sectional data of any one of powder materials supplied to the molding chamber; And a control computer for controlling the operation of the above-described components based on the cross-sectional data of the stored arbitrary object.

An arbitrary shape molding process of the SLS type 3D printer will be described below. The control computer controls the elevation driving of the material supply table of the material accommodating chamber and the shaping table of the material accommodating chamber and the driving of the material supplying device based on the stored cross sectional data so that the powder material is supplied to the upper surface of the shaping table step by step .

When the powder material is supplied to the upper surface of the shaping table of the shaping chamber step by step, the control computer controls the driving of the laser apparatus to sinter the powder material portion corresponding to each cross-sectional data.

When each cross section is thus sintered, an arbitrary shape corresponding to the three-dimensional data stored in the control computer is finally formed.

In the conventional 3D printer described above, the fine metal powder is irradiated with high energy of the laser to instantaneously melt the minute regions to be laminated, and the cooling is also instantaneously performed, which causes shrinkage stress.

In addition, due to the gas velocity being injected for preventing oxidation, the cooling rate of the laminated material accelerated further.

This phenomenon is accompanied by the accumulation of shrinkage stress proportional to the increase in the thickness of the laminate, and there is a problem in that cracks are generated in the laminated parts when laminated over a certain thickness.

In addition, the scattering of the byproducts generated as the laser is irradiated on the material causes an error in the laser irradiation focus, and the scattered by-product (the high energy laser is irradiated to cause the explosion in the process of melting the fine powder (A similar phenomenon appears) and small grain particles in the form of balls are scattered and scattered).

In the conventional DED method, an assistive technology using a gas for improving the quality of a laminated part for smooth supply of powders or prevention of oxidation is applied. Particularly, in the PBF method, an auxiliary device for improving the quality of a laminated part using gas It is insufficient.

The present invention can maintain the material and working space at a high temperature continuously, reduce the shrinkage stress of the molding, prevent cracking in the molding, improve the quality of the molding, and reduce the metal fume And smog are removed quickly. Elements affecting laser irradiation (effects of scattering particles: particles scattered in a ball shape are restored to the lamination part or placed on a newly supplied powder to act as defects in the lamination structure) , And it is possible to prevent the error phenomenon of the laser focus. The gas sucked together with the by-product is separated from the by-product again through the gas processing unit, and then supplied again to the working space to circulate the gas. The present invention also provides a 3D printing system capable of reducing energy required for printing.

The 3D printing system according to the present invention includes a 3D printer for printing a molding object by sequentially applying a metal powder as a material to a laminated bed of a work part and then sintering only a desired part by irradiating a laser, A gas spraying part provided at one side of the chamber for spraying a gas on the working part in the chamber; and a gas spraying part provided on the other side of the chamber facing the gas spraying part. A gas suction part for sucking the gas injected to the working part, a by-product containing metal fume and smog generated by the laser irradiation on the horizontal line, and a tube for flowing the fluid to the gas spray part and the gas suction part The metal fume and the smog are separated from the by-product sucked through the gas suction unit to extract the gas, Minutes and a gas processing section for Saburo circulation.

At this time, the 3D printer according to the present invention comprises a material storage part for storing a certain amount of metal powder as a material, and a metal powder, which is provided in front of the material storage part and supplied from the material storage part, A laser module unit for irradiating a laser beam onto a metal powder, which is a material layered on a laminated bed of the working unit, which is provided on an upper portion of the working unit and which is selectively moved in X and Y coordinates; A work recovery unit which is provided in front of the work unit and which recovers the excess material left over from the laminated bed of the work unit and which is left over from the work storage unit; And a material supply unit for supplying a predetermined amount of material.

The 3D printer according to the present invention includes a first heat source provided on one side of the material storage unit and providing heat to the material accommodated in the material storage unit, and a second heat source provided on the laminated bed of the working unit, A second heat source for supplying heat to the workpiece; and a gas supply unit for supplying heat to the gas injected into the chamber to convert the gas to be injected into hot gas to be injected into the chamber, And a third heat source providing heat.

The gas treatment unit according to the present invention may further include a particle trapping unit for trapping particles in the by-product that is sucked through the gas suction unit, a pipe connected to the particle trapping unit through a pipe through which the fluid flows, A gas compression feeder connected to the filter and a tube through which the fluid flows, for compressing and supplying the gas filtered by the filter; and a pipe connected to the gas compression feeder through which the fluid flows, And a heater for heating the gas to be heated at the temperature.

The gas injection unit according to the present invention is characterized in that the gas injection unit comprises a cylindrical nozzle body having a longitudinally elongated nozzle having a length in a horizontal direction to jet the gas into a laminar flow or a long rectangular hole having a length in a horizontal direction on one side of a rectangular nozzle body So that the gas can be injected into the laminar flow.

In addition, the gas injection unit according to the present invention is provided in a plurality of the gas injection units, and the gas suction unit is provided in the laser module, and the intake port is formed in a coodle shape on the upper side of the laser irradiation point So that gas and by-products can be sucked in a vertical line.

The 3D printing system according to an embodiment of the present invention has the following effects.

First, the material and work space are kept at a high temperature continuously, and the shrinkage stress of the molding is reduced, so that no crack is generated in the molding, thereby improving the quality of the molding.

Second, the byproducts generated by the laser irradiation are sucked together with the gas supplied to the work space and then separated from the gas to quickly remove metal fumes and smog scattered at the laser irradiation point in the work space. It is possible to prevent an error phenomenon of the laser focus and to prevent defects of the laminated structure which are generated by resting the scattered ball-shaped particles on the newly supplied powder.

Thirdly, the gas sucked together with the by-product is separated from the by-product through the gas processing unit, and thereafter, the energy for keeping the gas at the designated temperature is also reduced as well as the gas consumed by re- .

FIG. 1 is a view illustrating a configuration of a 3D printing system according to an exemplary embodiment of the present invention. Referring to FIG.
2 is a view illustrating a state of a laminated bed to which a bolt fastening and fixing method is applied according to an embodiment of the present invention.
3 is a view illustrating a state of a laminated bed to which a clamp fixing method is applied according to an embodiment of the present invention.
4 is a view illustrating a state of a laminated bed to which a pair of clamp fixing methods is applied according to an embodiment of the present invention.
FIG. 5 is an exemplary view showing a cylindrical gas ejecting part and a corresponding gas sucking part according to an embodiment of the present invention. FIG.
6 is a view illustrating a quadrangular gas ejector according to an embodiment of the present invention and a corresponding gas suction unit.
FIG. 7 is a view illustrating a configuration of a 3D printing system according to another embodiment of the present invention.
FIG. 8 is an exemplary view showing a gas ejecting portion and a corresponding gas sucking portion of the 3D printing system according to another embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor should appropriately interpret the concepts of the terms appropriately The present invention should be construed in accordance with the meaning and concept consistent with the technical idea of the present invention.

Therefore, the embodiments described in the present specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention, and not all of the technical ideas of the present invention are described. Therefore, at the time of the present application, It should be understood that variations can be made.

The present invention provides a plurality of heat sources in a work storage space and a work storage space so as to reduce the shrinkage stress of a molding to be printed by melt sintering of a metal powder as a material so as to prevent cracks, In addition to maintaining the space at a high temperature, it recovers the by-product gas containing injected inert gas at the working space and the by-product containing metal fumes and smog scattered by melting of the material due to the laser, And a 3D printing system for extracting only the gas from the by-product and circulating the gas to the work space again, will be described with reference to the drawings.

1 to 8, a 3D printing system according to an embodiment of the present invention includes a 3D printer 100, a chamber 101, a gas injection unit 200, a byproduct suction unit 300, and a gas processing unit 400 First, the 3D printer 100 applies a powdery material to a laminate bed in a layer form, irradiates a laser to sinter the desired portion, and repeats the process repeatedly to print a 3D model.

In this case, the 3D printer 100 includes a material storage unit 110 for storing a predetermined amount of metal powder. The material storage unit 110 may be configured to supply heat to a material And the first heat source 112 is provided to keep the material at a high temperature.

The first heat source 112 may be an electric heater that dissipates heat by an external power source.

The work part 120 is provided in front of the work storage part 110. The work part 120 is supplied from the work storage part 110 by the work supply unit 111 moving forward from the rear side The metal powder as a material is laminated on the laminated bed 121 in the form of a layer.

The second heat source 122 supplies heat to the laminated bed 121 so that the material stacked in the form of a layer is maintained at a predetermined temperature in the laminated bed 121, So that the laminated material is maintained at a high temperature.

Here, it is preferable that the second heat source 122 is provided as an electric heater that dissipates heat by an external power source.

2, the laminated bed 121 includes a laminated substrate 123 and a laminated block 124. The laminated substrate 121 includes a laminated substrate 121, (123) is a plate, and the upper surface thereof is sintered with a workpiece.

At this time, the laminated substrate 123 is provided with a peeling thin plate which is selectively peeled from the upper surface after being bonded to the upper surface of the laminated substrate 123. When the thin film to be peeled off is obtained on the upper surface of the laminated substrate 123, Since the sculpture is detached from the laminate board 123 as it peels off from the laminate board 123, the thin film for peeling is adhered to the upper surface of the laminate board 123, so that the sculpture can be easily obtained.

The laminated block 124 is a hexahedron having a larger area than the laminated substrate 123. The second heat source 122 is disposed at a predetermined interval in the interior of the laminated block 124 and a seating groove in which the laminated substrate 123 is seated is formed on the upper surface. .

The laminated board 123, which is formed on the front and rear ends of the laminated block 124 by the seating grooves of the laminated block 124 and is seated in the seating groove of the laminated block 124, The laminated board 123 that is seated in the seating groove of the laminated block 124 passes through the edge of the laminated board 123 and is fastened to the laminated block 124 The laminated substrate 123 may be fixed to the seating groove of the laminated block 124. [

The laminated bed 121 according to an embodiment of the present invention is not limited to the bolt fixing method for fixing the laminated board 123 to the laminated block 124 by the bolt fastening, (123) are compatible with each other, and a clamping and fixing method may be applied so as to be fixed to the lamination block (124).

Referring to FIG. 3, in order to implement the clamping and fixing method, guides 125 may be provided along the longitudinal direction on both left and right sides of the laminated block 124.

A clamp 126 is provided on the seating groove of the lamination block 124 to move along the longitudinal direction of the seating groove. The clamp 126 is provided on the left and right of the clamp 126, And the clamp 126 is guided by the pair of guides 125 and selectively moves along the longitudinal direction of the mounting groove of the lamination block 124. [

At this time, a conveying means 127 is provided at the center of the seating groove of the stacking block 124, and the conveying means 127 selectively conveys the clamp 126 in the longitudinal direction before and after the seating groove.

At this time, when the conveying screw is employed as one example of the conveying means 127, a step is formed along the seating groove on the rear side of the lamination block 124, a clamp 126 is provided in front of the step, The lower part of the clamping plate 126 is screwed to the conveying screw 127 which is the conveying unit 127. When the conveying screw rotates clockwise, the clamp 126 advances along the longitudinal direction of the receiving groove, And when the conveying screw rotates in the counterclockwise direction, the clamp 126 moves backward along the lengthwise and backward directions of the seating groove, and the distance between the clamp 126 and the step is gradually narrowed.

When the clamp 126 is moved backward by the clamp 126 to move the clamp 126 to the end of the mounting recess, the stacked substrate 123, which is positioned between the mounting recess and the clamp 126, The stacked substrate 123 is clamped between the clamp 126 and the stacked block 124 and the stacked substrate 123 is fixed on the seating groove of the stacked block 124. By the advancement of the clamp 126, The clamping of the laminate substrate 123 is released and the laminate substrate 123 positioned on the seating groove of the laminate block 124 moves away from the clamp 126. As a result, Is released.

In addition, as shown in FIG. 4, the clamps 126 may be provided on the mounting grooves of the laminated block 124 in pairs.

The pair of clamps 126 are disposed symmetrically with respect to each other along the longitudinal direction on the seating groove of the laminated block 124, So that the laminated board 123 is fixed on the seating groove of the laminated block 124.

The laser module unit 140 is disposed at an upper portion of the work unit 120. The laser module unit 140 selectively moves the X coordinate and the Y coordinate of the work unit 120, ), A laser is irradiated to a metal powder as a layer on a substrate, and the material is sintered firmly while being melted. The material to be laminated again on the layer is sintered again, and the molding is printed step by step.

In addition, a material recovery unit 130 is provided in front of the work unit 120. The material recovery unit 130 is configured such that metal powder, which is an excess material remaining after forming a layer, As shown in FIG.

A chamber 101 is provided on the upper side of the 3D printer 100. The chamber 101 seals the work space of the 3D printer 100 from the outside.

At this time, the work space formed in the chamber 101 may have a separate heat source to maintain a high temperature.

5 and 6, a gas injection unit 200 is provided at one side of the chamber 101. The gas injection unit 200 includes a third heat source, Temperature hot gas is injected into the work space as a laminar flow by a gas which is heavier than oxygen so as to prevent contact between the work and oxygen, Keep it at high temperature.

Here, the gas spraying unit 200 may include a cylindrical nozzle body having a horizontally elongated nozzle formed on one side thereof to jet a hot gas into a laminar flow, or a horizontally long nozzle body on one side of a rectangular nozzle body It is possible to form a nozzle having a long hole shape and to inject a high temperature gas into the laminar flow.

A gas suction unit 300 is provided on the other side of the gas injection unit 200 and opposed to the chamber 101. The gas suction unit 300 is provided on the other side of the chamber 200, And the by-product containing the metal fume and the smog generated by the laser irradiation.

At this time, the gas suction unit 300 is provided on a side surface of the chamber 101 facing the gas spray unit 200, and the suction port of the gas suction unit 300 is also formed on the side surface of the gas spray unit 200 The gas suction part 300 is formed in a shape of a slot having the same shape as that of the nozzle shape. The side surface of the gas suction part 300 is formed in a cone shape having a wide entrance at a gas inlet and a narrower entrance at an exit, The gas is sucked into the gas suction unit 300 without diffusing, dispersing, or convecting in the chamber 101, so that the gas injected from the gas spray unit 200 flows into the laminar flow.

As shown in FIGS. 7 and 8, a plurality of the gas injection units 200 may be provided in front, rear, left, and right sides of the chamber 101.

At this time, the gas suction unit 300 is not formed on the side surface of the chamber 101 opposite to the gas spray unit 200, but is provided in the laser module unit 140, and a claw- And the gas and the by-product are sucked in a vertical line.

In addition, it is preferable that the coin-shaped inlet of the gas suction unit 300 is connected to a body made of a flexible tube so as to move in conjunction with the motion of the laser module unit 140.

The coin-shaped intake port of the gas suction unit 300 is bent at the lower end thereof to form a pocket connected along the periphery thereof. The relatively heavy particles among the by-products sucked through the suction port of the gas suction unit 300 And can be collected in the pocket by natural dropping.

The gas sucking unit 300 is made of a material through which a laser can penetrate and the laser module unit 140 is disposed on the gas sucking unit 300 so that the laser module unit 140 The laser can be irradiated on a vertical line, so that gas and by-products can be sucked in a vertical line.

In addition, the 3D printing system according to an embodiment of the present invention includes a gas processing unit 400 connected to the gas spraying unit 200 and the gas suction unit 300 through a tube through which a fluid flows, Separates the metal fume and the smog from the byproduct sucked through the gas suction unit 300, extracts the gas, and circulates the extracted gas to the gas spray unit 200.

At this time, the gas processing unit 400 includes a particle collecting unit 410. The particle collecting unit 410 collects particles from the by-product sucked through the gas sucking unit 300, passes through the particle collecting unit 410 A byproduct enters the filter 420, which is connected to the particle trap 410 through a tube through which the fluid flows.

In the filter 420, the gas is filtered by the collected by-products, and the gas filtered by the filter is introduced into the gas compression feeder 430 connected to the filter 420 through a pipe through which the fluid flows.

The gas compression feeder 430 compresses the gas filtered by the filter 420 and supplies the compressed gas to a heater 440. The heater 440 is connected to the gas compression feeder 430 through a pipe And the gas compressed in the gas compression feeder 430 is heated to the corresponding temperature.

At this time, the provided gas is supplied to the gas injecting unit 200 connected to the heater 440 through a pipe through which the fluid flows, so that the gas is circulated.

Here, a valve 450 is provided on the pipe by the heater 440 and the gas injecting unit 200 to selectively open and close a pipe through which the gas flows.

Further, a gas filling part 460 is further provided at the rear end of the gas compression / supply device 430, so that the amount of the insufficient gas can be selectively filled.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

100: 3D printer 101: chamber
110: Material storage unit 111: Material supply unit
112: first heat source 120:
121: laminated bed 122: second heat source
130: material recovery unit 140: laser module unit
200: gas injection part 300: gas suction part
400: gas treatment unit 410: particle trapping unit
420: filter 430: gas compression feeder
440: heater 450: valve
460: gas filling part

Claims (11)

A 3D printer for printing a molding by continuously applying a metal powder as a layer on a laminated bed of a work part and then sintering only a desired part by irradiating a laser;
A chamber for sealing the work space on the upper side of the 3D printer unit from the outside;
A gas spraying part provided at one side of the chamber, for spraying a gas onto the working part in the chamber;
A gas suction part provided on the other side of the chamber facing the gas spraying part and sucking the gas sprayed to the working part and the byproduct including the metal fume and the smog generated by the laser irradiation on the horizontal line; And
A gas processing unit connected to the gas spraying unit and the gas suction unit and connected to the tube through which the fluid flows, separates the metal fume and the smog from the by-product sucked through the gas suction unit, extracts the gas, and circulates the extracted gas to the gas spray unit A 3D printing system.
The method according to claim 1,
The 3D printer
A material storage part for storing a predetermined amount of metal powder as a material;
A work unit disposed in front of the work storage unit and stacking the metal powder supplied from the work storage unit in a layer form on a laminated bed;
A laser module unit provided on the work unit and irradiating a laser to a metal powder, which is a material layered on a laminated bed of the work unit, while selectively moving in X coordinate and Y coordinate;
A material collecting unit provided in front of the working unit and collecting a surplus material remaining in the layer in the laminated bed of the working unit;
And a material supply unit for reciprocating from the material storage unit rearward to the material recovery unit forward and supplying a predetermined amount of the material stored in the material storage unit.
The method of claim 2,
The 3D printer
A first heat source provided at one side of the material storage unit to supply heat to the material accommodated in the material storage unit;
A second heat source provided on the laminated bed of the working unit, for providing heat to the material applied to the laminated bed;
And a third heat source provided in the gas injection unit for supplying heat to the gas injected into the chamber so that the injected gas is converted into hot gas and injected thereby to provide heat to the working unit in the chamber. Printing system.
The method according to claim 1,
The gas processing unit
A particle collector for collecting particles in the by-product sucked through the gas suction unit;
A filter connected to the particle sorter through a tube through which a fluid flows and to filter the gas in the by-product in which the particles are collected;
A gas compression feeder connected to the filter through a pipe through which the fluid flows, for compressing and supplying the gas filtered by the filter;
And a heater connected to the gas compression feeder through a pipe through which the fluid flows, and heating the gas to be fed from the gas compression feeder to a corresponding temperature.
The method according to claim 1,
The gas-
A 3D printing system for forming a nozzle having a long length in a horizontal direction on one side of a cylindrical nozzle body to inject gas into a laminar flow.
The method according to claim 1,
The gas-
A 3D printing system in which a nozzle having a long length in a horizontal direction is formed on one side of a rectangular nozzle body to inject gas into a laminar flow.
The method according to claim 1,
The gas-
A 3D printing system provided in front of, behind, left, and right of the chamber.
The method of claim 7,
The gas-
And a 3D printing system provided in the laser module, the suction port being located above the laser irradiation point in the form of a coil, to draw in gas and by-products vertically.
The method of claim 3,
The laminated bed
A laminate substrate having a plate on which a workpiece is output on an upper surface thereof;
And a stacking block having a second heat source inside the first heat source and spaced apart from the first heat source and having a seating groove on the upper surface thereof for receiving the laminated substrate.
The method of claim 9,
The laminated substrate
And a peelable thin plate which is selectively peeled from the upper surface after the upper surface thereof is contacted.
The method of claim 9,
The laminated block
A pair of guides provided on both left and right sides along the longitudinal direction;
A clamp coupled to the pair of left and right guides, respectively, and selectively moving along the longitudinal direction of the seating groove;
And a transporting means provided longitudinally at the center of the stacking block for selectively transporting the clamp in the longitudinal direction of the mounting recess.

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