WO2022097771A1

WO2022097771A1 - 3d printing method for forming stacked structure of different materials

Info

Publication number: WO2022097771A1
Application number: PCT/KR2020/015358
Authority: WO
Inventors: 김도현; 오진호; 최형일
Original assignee: 주식회사 엠오피
Priority date: 2020-11-03
Filing date: 2020-11-05
Publication date: 2022-05-12
Also published as: KR102341208B1

Abstract

The present invention relates to a 3D printing method for forming a stacked structure of different materials, comprising: a first stacking step of providing a first slurry on a stage; a first curing step of emitting light at the first slurry to form one cross-section of a first target object and one cross-section of a first peripheral object spaced a predetermined distance from the first target; a step of repeatedly performing the first stacking step and the first curing step until the first target object is formed; a second stacking step of providing a second slurry so that the first target object is covered; a second curing step of emitting light at the second slurry to form one cross-section of a second target object and one cross-section of a second peripheral object spaced a predetermined distance from the first target object; and a step of repeatedly performing the second stacking step and the second curing step until the second target object is formed.

Description

3D printing method for forming laminated structures with different materials

The present invention relates to an additive manufacturing process in which interlayer mixing is prevented, and more particularly, to a 3D printing method for forming a structure laminated with different materials without a mixing area by curing the entire surface of each layer as well as a target object. .

1 is a cross-sectional view showing the configuration of a multi-component laminated structure, and FIGS. 2(a) to 2(f) are process diagrams illustrating a 3D printing method for forming a structure laminated with different materials.

The structure 110 is 3D printed in such a way that each section is laminated and cured in a very thin layer. In this case, in order to produce a structure in which the composition is different while the target object is laminated, it is preferable to sequentially manufacture the composition by specifying the composition for each part. In other words, it is manufactured in such a way that laminating one part with the same composition and laminating the next part with the next composition are repeated. For example, in the case of FIG. 1 , the first object 110a is configured by stacking six cross-sections 111a of the first object having the same composition. When this lamination method is followed, there is a problem in that a non-homogeneous mixed region is formed on one end surface 111b of the second object, which is an initial lamination cross-section of the second object 110b with a changed composition.

This problem will be further described with reference to the manufacturing method of FIG. 2 .

In order to form a layered structure having a different composition, different materials must be stacked for each layered structure. Although there may be various methods of stacking with different materials, a method of forming a stacked structure in which a material set for each stacked structure is discharged to one side of a stage and spread over the entire surface with a blade is suitable.

Specifically, as shown in FIG. 2A , the first slurry 280 is discharged to one side of the stage 240 through the first nozzle 260 .

Thereafter, as shown in FIG. 2B , the blade 250 moves from one side of the stage 240 to the other side while being spaced apart from the stage 240 by a uniform distance. Due to this, the first slurry 280 is spread as a first slurry layer 281 having a thickness equal to the distance the blade 250 is spaced apart from the stage 240 . Thereafter, as shown in FIG. 2C , one end surface 211a of the first object of the first slurry layer 281 is cured, and an area other than the object 221a (hereinafter, one cross-section of the first uncured area) is not cured. put Thereafter, the steps of (a) to (c) of FIG. 2 are repeated until the first object 110a is manufactured (refer to (d) of FIG. 2).

In order to manufacture the second object, the second slurry 290 is discharged to one side of the stage 240 through the second nozzle 270 in the same manner as in FIG. 2A , as shown in FIG. 2D . As shown in FIG. 2(e), the second slurry 290 is moved from one side of the stage 240 to the other side by a uniform distance with the blade 250 to transfer the second slurry 290 to the first object 210a. and spread over the first uncured area 220a. At this point, a problem arises. This is because interlayer mixing occurs in the process of spreading the layers with the blade 250 .

The already hardened portion of the first object 210a is not a problem, but since the uncured first uncured region 220a is a fluid, the upper and lower layers may be mixed to form a second slurry layer mixing region 291b. In particular, when the thickness of the second slurry layer 290 is thin, the composition of the entire layer is changed only by a little mixing. Alternatively, when the viscosity of the second slurry 290 is high, the pressure on the upper part of the layer greatly affects the lower part, so there is a great risk of mixing.

Although mixing occurs in the first uncured region 220a as described above, the mixed region formed around the first object 210a may be pushed up on the first object 210a as well. In this case, the mixed region 291b and the second slurry layer non-mixed region 292b are simultaneously present on the first object 210a. Accordingly, a heterogeneous mixed region is formed in the structure. In this case, as shown in (f) of FIG. 2 , there is a problem in that the mixed region 215b and the non-mixed region 211b simultaneously exist on one end surface of the second object even after sintering.

In addition, a frictional force acts on the second slurry 290 while the blade 250 moves. The second slurry ( As the 290 flows along the blade 250, a rounding phenomenon in which the thickness of the second slurry 290 stacked on the edge of the first object 210a is locally reduced may occur. Since the rounding phenomenon may continuously occur in the process of forming the second object, it causes a problem of reducing the precision of the structure. Accordingly, technology development is required to solve the interlayer mixing problem and rounding problem of the first slurry 280 and the second slurry 290 described above.

On the other hand, the above-mentioned background art cannot necessarily be said to be a known technology disclosed to the general public prior to the filing of the present invention.

An embodiment of the present invention aims to provide a 3D printing method for preventing interlayer mixing in a 3D printing method for forming a structure laminated with different materials.

As a technical means for achieving the above-described technical problem, a 3D printing method for forming a structure laminated with different materials according to an aspect of the present invention is a first lamination step of providing a first slurry on a stage, the first A first curing step of irradiating light to the slurry to form a cross-section of a first object and a cross-section of a first peripheral object spaced apart from the first object by a predetermined distance, until the first object is formed Repeating the lamination step and the first curing step, a second lamination step of providing a second slurry to cover the first object, and irradiating light to the second slurry to form a cross-section of the second object and the second A second curing step of forming a cross section of a second peripheral object spaced apart from the target by the predetermined distance, and repeating the second laminating step and the second curing step until the second target is formed. .

According to an aspect of the present invention, the first slurry and the second slurry may have different colors.

According to one aspect of the present invention, the predetermined distance may have a size of 0.01 mm or more and 10 mm or less.

According to an aspect of the present invention, the 3D printing method may be a DLP method.

According to an aspect of the present invention, the thickness of one cross-section of the second slurry may be 0.1 mm or less.

According to another aspect of the present invention, the second lamination step may include: discharging the second slurry to one side of the stage using a nozzle; and applying the second slurry on the stage using a blade.

According to claim 1, wherein in the first curing step, the curing time may be determined according to the type of the first slurry, and in the second curing step, the curing time may be determined according to the second slurry.

According to another aspect of the present invention, the 3D printing method may separate the object and the surrounding object after the steps of repeating the second lamination step and the second curing step are completed.

According to another aspect of the present invention, the first curing step includes curing the first peripheral object in the form of a plurality of pieces, and the second curing step includes curing the second peripheral object in a plurality of pieces. It may include a step of curing in the form of a piece.

According to another aspect of the present invention, the first curing step includes curing the first peripheral object into a piece in which an area close to the first object is smaller than an area far from the first object, The second curing step may include curing the second peripheral object into a piece in which an area close to the second object is smaller than an area far from the second object.

According to any one of the means for solving the problems of the present invention described above, in an embodiment of the present invention, there is an effect of preventing the mixing of materials of the upper and lower layers during the lamination process.

According to any one of the above-described means for solving the problems of the present invention, in an embodiment of the present invention, since mixing of upper and lower layers is suppressed during the lamination process, it is possible to stably form a structure laminated with different materials.

According to any one of the means for solving the problems of the present invention described above, an embodiment of the present invention has an effect of facilitating separation of an object and a peripheral object.

1 is a cross-sectional view showing the structure of a multi-component laminate structure.

2 (a) to (f) are schematic diagrams sequentially showing a general 3D printing method.

3 is a flowchart illustrating a 3D printing method according to an embodiment of the present invention.

4 (a) to (f) are step-by-step schematic diagrams for explaining the 3D printing method of FIG. 3 .

5 is an example of a plan view of a laminate molded by the 3D printing method of FIG. 3 .

6 is an example according to a plan view of a laminate molded by the 3D printing method of FIG. 3 .

FIG. 7 is another example of a plan view of a laminate molded by the 3D printing method of FIG. 3 .

8 is a perspective view of an artificial tooth laminated with different materials molded by a 3D printing method according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art can easily implement them. However, the present invention may be embodied in several different forms and is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Throughout the specification, when a part is "connected" with another part, this includes not only the case where it is "directly connected" but also the case where it is "indirectly connected" with another element interposed therebetween. . Also, when a part "includes" a certain component, it means that other components may be further included, rather than excluding other components, unless otherwise stated.

This specification is a description of "3D printing". “3D printing” is also referred to as additive manufacturing, and refers to a method of manufacturing an article by laminating a plurality of layers and curing a portion of each layer according to the shape of the object to be manufactured. As used herein, the term “structure” refers to a structure to be manufactured. In the present specification, “n-th object” refers to a continuous portion of the same composition constituting the structure, and is located at the n-th position (n is a natural number) from the bottom. “N-th peripheral object” refers to a part that is molded from the same material as the n-th object at the same height as the n-th object, but does not correspond to the structure. In the present specification, “one cross-section” means a layer corresponding to the cross-section of the n-th object and the n-th peripheral object. The “n-th slurry” means a suspension as a raw material of the material constituting the n-th object and the n-th peripheral object. The suspension may have a composition in which microparticles of ceramic, metal, or polymer are mixed with a photocurable monomer. However, the present invention is not limited thereto, and the suspension may have a composition in which a microcapsule-type filler containing a functional material therein is mixed with a photocurable monomer. The composition may be a ratio for each component of the suspension, and properties of the suspension and the cured object and surrounding may be different depending on the composition.

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

3 is a flowchart illustrating a 3D printing method according to an embodiment of the present invention, and FIGS. 4 (a) to (f) are step-by-step schematic diagrams for explaining the 3D printing method of FIG. 3 .

A 3D printing method for forming a structure laminated with different materials according to an embodiment of the present invention will be described in detail with reference to FIGS. 3 and 4 .

First, referring to FIG. 3 , the 3D printing method for forming a structure laminated with different materials according to the present invention includes a first lamination step ( S310 ) of providing a first slurry layer on a stage, and light on the first slurry layer. A first curing step (S320) of forming a cross-section of a first object and a cross-section of a first peripheral object spaced apart from the first object by a predetermined distance by irradiating (S320), a first lamination step until the first object is formed, and Repeating the first curing step (S330), a second laminating step of providing a second slurry layer to cover the first object (S340), irradiating light to the second slurry layer to obtain a cross section and a second surface of the second object 2 A second curing step (S350) of forming a cross section of a second peripheral object spaced apart from the target by a predetermined distance, and repeating the second laminating step and the second curing step until the second target is formed (S360) includes

The first stacking step S310 is the same as described with reference to FIG. 2 . As shown in FIGS. 4A and 4B , the first slurry 280 is discharged to one side of the stage 240 using the first nozzle 260 , and the first slurry 280 is discharged using the blade 250 . ) on the stage 240 to form a first slurry layer 281 .

As shown in (c) of FIG. 4 , the first curing step (S320) includes a cross section 411a of the first object of the first slurry 280 applied in the first lamination step (S310), and a preset in the first object. The remaining portion except for the distance (hereinafter, one cross-section of the first peripheral object, 421a) is cured. Accordingly, a portion corresponding to within a predetermined distance from one end surface 411a of the first object remains in an uncured fluid state.

The DLP method is suitable for the curing method in the present invention. The DLP method generates two-dimensional cross-sectional data for each layer by slicing the data produced in 3D, and based on the two-dimensional cross-sectional data, projects a high-resolution projection light onto a photocurable resin to harden the layers. . Since the present invention hardens most areas of the surface, the time required for curing is greatly increased when using a point-hardening 3D printing technique. Even if this is increased, it is advantageous because the time required for curing is almost equal.

The first stacking step S310 and the first curing step S320 are repeated until the first object 410a is completed. (S330) Accordingly, the first object 410a and the first peripheral object 420a are It may be separated by a region separated by a predetermined distance from the first object 410a.

It is preferable that the predetermined distance spaced apart is longer than 0.01 mm. If it is narrower than this, the first object 410a and the first peripheral object 420a are not clearly separated, or it is difficult to separate after completion.

The second lamination step (S340) is a step of discharging the second slurry 290 to one side of the stage 240 using the second nozzle 270 and the blade 250 as shown in FIGS. 4(d) and (e). ) to apply the second slurry 290 on the stage 240 . At this time, since the first object 410a and the first peripheral object 420a to which the second slurry 290 is applied are both cured, they do not have fluidity. Therefore, mixing does not occur in the corresponding area during the coating process. However, since a portion corresponding to within a predetermined distance from the first object 410a is not cured, the first slurry 280 and the second slurry 290 may be mixed.

Therefore, it is preferable that the predetermined distance spaced apart from the first object 410a in which curing does not occur is 10 mm or less. This is because mixing occurs more easily as the area where the flow occurs is widened, so if there is an uncured area in an area wider than 10 mm, mixing may occur in that area.

In some embodiments, the second nozzle 270 may be the same nozzle as the first nozzle 260 . In this case, before the first slurry 280 in the nozzle is all consumed, the second slurry 290 is injected into the nozzle, and a portion of the remaining first slurry 280 remaining in the nozzle is stirred with the second slurry 290 . Thus, a sequential change in composition can be induced.

As shown in (f) of FIG. 4 , the second curing step ( S350 ) includes a cross-section 411b of the second object of the second slurry layer 291 applied in the second lamination step ( S340 ), and one of the second objects. The remaining portion spaced apart by a predetermined distance from the cross-section 411b (hereinafter, one cross-section of the second peripheral object, 421b) is cured. Accordingly, a portion corresponding to within a predetermined distance from one end face 411b of the second object is not cured and remains in a fluid state.

In this case, in the first curing step ( S320 ), the curing time is determined according to the type of the first slurry ( 280 ), and in the second curing step ( S350 ), the curing time is determined according to the second slurry ( 290 ). In other words, the first slurry 280 and the second slurry 290 may be of different types, and the curing time may be different depending on the type of slurry. For example, when the color of the first slurry 280 is white and the second slurry 290 is colored, the curing time of the first slurry 280 may be shorter than that of the second slurry 290 .

The second laminating step (S340) and the second curing step (S350) are repeated until the second object is completed. (S360) Accordingly, the first object 410a, the second object, and the first peripheral object 420a are repeated. and the second peripheral object may be separated by a region separated by a predetermined distance from the first object 410a and the second object.

An n-th object may be further manufactured in the same manner. At this time, the n-th object is formed apart from the n-th object by a predetermined distance, and the n-th object and the n-th object are spaced apart, so the first object 410a to the n-th object and the first peripheral object 420a to nth peripheral objects may be separated.

After lamination and curing are completed, the completed structure is separated from the first to n-th surrounding objects. (S370)

In order for the structure to form a three-dimensional structure, the side surfaces of the first to n-th objects 510 must form a closed curved surface. Accordingly, the regions spaced apart by a predetermined distance from the first to n-th objects 510 form a closed curve dividing the first to n-th objects 510 and their periphery 520 in a plan view. Accordingly, the first to n-th objects 510 may be separated from the first to n-th peripheral objects 520 .

In order to prevent damage to the first to n-th objects 510 that may occur when the first to n-th peripheral objects are removed and to easily remove the first to n-th peripheral objects, the first to n-th peripheral objects are a plurality of peripheral pieces. 610 may be formed. The peripheral piece 610 may be formed in such a way that the space between it and the neighboring peripheral piece 610 is not cured in the curing step.

When the structure is manufactured through the process of FIGS. 3 to 4 , it is easy to manufacture the structure in a form surrounded by the first to n-th surrounding materials as shown in FIG. 5 . In this case, depending on the curvature of the structure, the structure may become a structure in which the structure is trapped by the periphery, or damage to the structure that may occur in the process of removing the periphery may occur. In particular, in the case of an undercut structure in which the side surfaces of the first to n-th objects 510 are protruded or recessed, the first to n-th peripheral objects and the first to n-th objects 510 are engaged with each other to form the first to n-th objects. It may be difficult to separate the first to nth peripheral objects from the first to nth objects 510 . However, when the first to n-th peripheral objects are composed of a plurality of pieces 610 as shown in FIG. 6 , the first to n-th objects 510 are formed by removing the pieces 610 of the periphery without interfering with the sides. Since it can be easily removed, a structure having a complicated external shape can be stably formed.

Referring to FIG. 7 , the first to n-th objects 510 close to the area (ie, the area where the objects are located) are provided with a small piece 710 near the peripheral object, and the area far from the structure is relatively large. A peripheral distant piece 720 may be provided.

When the first to n-th objects 510 are configured in a complex shape and include a thin portion having a small thickness, the problem of breaking the thin portion due to the impact applied in the process of separating the first to n-th peripheral objects can happen When the first to n-th peripheral objects are divided into a plurality of peripheral pieces, the uncured region dividing each peripheral piece may serve as a buffer for absorbing a force applied when separating the peripheral pieces. Therefore, as shown in FIG. 7 , by varying the sizes of the part close to the structure and the part farther away, it is possible to increase the safety at the time of separation by increasing the density of the buffer part near the structure where the force must be sufficiently absorbed.

Artificial teeth are made of ceramic materials such as zirconia. Artificial teeth are configured to have different colors for each object stacked in order to imitate the color of real teeth. By preparing slurries as a suspension in which zirconia powder with different pigments is suspended in a photocurable monomer, objects are sequentially stacked with a slurry suitable for each stacking order, and sintered to produce artificial teeth with a color similar to that of real teeth.

According to the present invention, by sintering not only the target material but also the surrounding material, interlayer mixing of the target material is prevented even when the composition is changed during lamination.

According to the present invention, by forming a peripheral object into a plurality of pieces, there is an effect of easily separating an object and a peripheral object after curing, and minimizing damage to the object during separation.

According to the present invention, interlayer mixing can be minimized in the lamination process, and mixing can be suppressed even when the lamination thickness is sufficiently thin or the viscosity of the slurry is increased. Accordingly, the quality and sophistication of the laminated structure composed of different materials may be improved.

The scope of the present invention is indicated by the following claims rather than the above detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be interpreted as being included in the scope of the present invention. do.

The 3D printing method of the present invention can be applied to any area for producing a multi-color or multi-component laminate structure. For example, the 3D printing method of the present invention can be applied to artificial teeth manufactured by 3D printing.

Claims

a first lamination step of providing a first slurry on a stage;

a first curing step of irradiating light to the first slurry to form a cross-section of a first object and a cross-section of a first peripheral object spaced apart from the first object by a predetermined distance;

repeating the first laminating step and the first curing step until the first object is formed;

a second lamination step of providing a second slurry to cover the first object;

a second curing step of irradiating light to the second slurry to form a cross-section of a second object and a cross-section of a second peripheral object spaced apart from the second object by the predetermined distance; and

3D printing method for forming a structure laminated with different materials, comprising repeating the second laminating step and the second curing step until the second object is formed.
The 3D printing method according to claim 1, wherein the first slurry and the second slurry have different colors.
The 3D printing method according to claim 1, wherein the predetermined distance has a size of 0.01 mm or more and 10 mm or less.
According to claim 1, wherein the 3D printing method 3D printing method for forming a structure laminated with different materials, characterized in that the DLP method.
The 3D printing method for forming a structure laminated with different materials according to claim 1, wherein the thickness of one section of the second slurry is 0.1 mm or less.
According to claim 1, wherein the second lamination step,

discharging the second slurry to one side of the stage using a nozzle; and

A 3D printing method for forming a structure laminated with different materials, comprising the step of applying the second slurry on the stage using a blade.
The different material according to claim 1, wherein in the first curing step, the curing time is determined according to the type of the first slurry, and in the second curing step, the curing time is determined according to the second slurry. 3D printing method for forming a laminated structure.
According to claim 1, wherein the 3D printing method 3D printing for forming a structure laminated with different materials, characterized in that the separation of the structure after the step of repeating the second lamination step and the second curing step is completed Way.
The method of claim 8, wherein the first curing step comprises:

Including the step of curing the first peripheral object in the form of a plurality of pieces,

The second curing step,

3D printing method for forming a structure laminated with different materials, characterized in that it comprises the step of curing the second peripheral object in the form of a plurality of pieces.
10. The method of claim 9, wherein the first curing step,

curing the first peripheral object into a piece in which an area proximate to the first object is smaller than an area far from the first object;

The second curing step,

and curing the second peripheral object into a piece in which an area close to the second object is smaller than an area far from the second object.