WO2019045536A1

WO2019045536A1 - Structure and design method for variable three-dimensional printing

Info

Publication number: WO2019045536A1
Application number: PCT/KR2018/010188
Authority: WO
Inventors: 이용구; 서해원; 조규진; 이대영; 주형준
Original assignee: 광주과학기술원
Priority date: 2017-08-31
Filing date: 2018-08-31
Publication date: 2019-03-07
Also published as: KR101992720B1; KR20190024445A

Abstract

A design method for four-dimensional printing is disclosed. A design method for four-dimensional printing according to an embodiment of the present invention comprises a method for designing a plane-shaped three-dimensional structure comprising a boundary that is not deformed under a specific condition, a behavior unit that is deformed under a specific condition inside the boundary, and a core connecting a plurality of behavior units or boundaries. The core is designed to adjust the bending angle between behavior units following deformation of the behavior units.

Description

Structure and design method for variable three-dimensional printing

The present invention relates to a structure and a design method for variable three-dimensional printing (four-dimensional printing). More particularly, the present invention relates to a structure and a design method for variable three-dimensional printing including a smart material.

Three-dimensional printing refers to the technique of extracting objects from a printer. It is called 3D printing in a similar way to existing printers that print letters on paper, but as a technique of making stereoscopic models.

Usually, printers use ink, but 3D printers use hardenable materials such as plastic. The difference is that existing printers print 2D documents such as documents or picture files, but 3D printers use 3D modeling files as output sources. Less than one or two hours or as long as a couple of hours, you can complete the model entered in the 3D printer.

In addition, if the shape of the three-dimensional printed material can change depending on the situation, this will again greatly expand the area of three-dimensional printing. Although research on various materials that can move by themselves for this technique called 4-dimensional printing is underway, research on designing a movable structure has not yet started.

Existing design techniques have a great limitation to be practically used because the range of the change is limited in that the movement is two-dimensionally restricted, or a simple shape of a line is bundled or a plane is bent.

We propose a 3D printing structure and its design method that can be changed into various forms by utilizing materials that deform under specific conditions.

A design method for four-dimensional printing is disclosed. A design method for four-dimensional printing according to an exemplary embodiment of the present invention includes a boundary that does not deform under specific conditions, a core that deforms in a certain condition inside the boundary, a core that connects a plurality of gull motors or a boundary, Dimensional structure of the shape, wherein the core is designed to adjust a different period of bending angle to the deformation of the gantry.

It is possible to produce various shapes without restriction by four-dimensional printing using the three-dimensional printing structure according to an embodiment of the present invention.

1 shows a four-dimensional printing structure according to an embodiment of the present invention.

2 shows a structure of a core according to an embodiment of the present invention.

Figure 3 shows a specific embodiment of the second part described above.

Figure 4 is a diagram showing the need for a core.

5 is a view for explaining a moving device according to an embodiment of the present invention.

6 is a flowchart illustrating a method of designing a four-dimensional printing structure according to an exemplary embodiment of the present invention.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. It should be understood, however, that there is no intention to limit the invention to the embodiments described below, and that those skilled in the art, upon reading and understanding the spirit of the invention, It is to be understood that this is also included within the scope of the present invention.

The accompanying drawings are merely exemplary and are not to be construed as limiting the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Further, even if specific parts such as installation positions are different, the same names are given when the functions are the same, so that the convenience of understanding can be improved. When there are a plurality of identical configurations, only one configuration will be described, and the same description will be applied to the other configurations, and a description thereof will be omitted.

Prior to describing the embodiment, the four-dimensional printing will be described.

Four-dimensional printing is performed by outputting a smart material, such as a shape memory alloy or a resin, using a three-dimensional printer in the form of a thin 2D shape, and changing the output object into another desired shape as the time or the surrounding environment changes . It can be pre-programmed to design what kind of condition to change to. At this time, the deformation condition may be various environments or energy sources such as heat, vibration, gravity, moisture, light, and pH. Four-dimensional printing is an area where industrial use is highly expected in terms of reduction of manufacturing time which is a big problem in conventional three-dimensional printing.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention to be described below relates to a structure design for variable three-dimensional printing (four-dimensional printing). The technique of designing the structure to be transformed into a desired shape is one of the core technologies of 4-dimensional printing. According to the present invention, a bending actuator capable of three-dimensional printing is proposed as an element structure capable of changing into a much more various form than a conventional one by connecting a specially designed core structure as a truss type using an intermediate connection portion.

As shown in FIG. 1, a four-dimensional printing structure 1 according to an embodiment of the present invention may include a core 10, a gantry synchronizer 20, and a boundary 30.

The four-dimensional printing structure 1 according to an embodiment of the present invention has a planar shape. In other words, the four-dimensional printing structure is printed in a planar shape (more precisely flat) by the first three-dimensional printer. In the case of general three-dimensional printing, the three-dimensional shape is modeled as described above, and the printer performs printing according to the modeled three-dimensional shape to produce a desired shape. However, in the case of the variable type three-dimensional printing structure according to the embodiment of the present invention, the three-dimensional shape is printed first in a plane shape considering the three-dimensional shape.

Therefore, there is no need to print in a desired shape from the beginning, and the printing structure produced in the shape of a plane has advantages of relatively simple printing and convenient portability. Therefore, after being initially made into a planar shape, it can be deformed into a desired shape by exposure to specific conditions during use.

At this time, the core 10 is a portion for connecting the plurality of gull motors 20. The core 10 comprises a relatively rigid portion and a relatively flexible portion. The core 10 adjusts the bending angle of the behavior period when the shape of the gull synchronizer 20 changes under certain conditions. The core 10 will be described in detail below.

The gating synchronizer 20 is a portion where the shape changes under a specific condition. The gantry synchronizer 20 is configured to change its shape under specific conditions. The first planar three-dimensional printing structure changes to a shape to be produced while the shape of the gantry synchronizer 20 changes. A detailed description of the gating synchronizer 20 will be given below.

The boundary 30 is a portion in which the shape is not changed under any condition, unlike the gull synchronizer 20. Boundary 30 refers to the portion that should not be deformed in its overall shape. The boundary 30 is configured such that the shape does not change under certain conditions unlike the gantry 20. Generally, the boundary 30 forms the outer shape of the shape and is provided inside the boundary 30 while the movable unit 20 is connected through the core 10. [

As described above, the core 10 can connect the gull synchronizer 20 or the boundary 30. The core 10 can adjust the connection angle between the gull synchronizer 20 or the boundary 30 between the gull synchronizer 20 or the boundary 30. [ The structure of the core 10 for adjusting the connection angle will be described below.

As shown in Figure 2, the core 10 is comprised of a first portion 11 and a second portion 12. Here, the second part 11 is provided on at least one surface of the first part 11. The first portion 11 is made of a relatively hard material compared to the second portion 12. The first part 11 does not play a direct role in adjusting the bending angle between the gull motors 20.

On the other hand, the first portion 11 may have a shape corresponding to the shape of the second portion 12. 2, when the first portion 11 has a spherical shape, the second portion 12 may have the shape of an arc corresponding to the shape of the spherical portion. Therefore, when the second portion 12 is bent by a change in the shape of the gantry 20, the degree of bending can be adjusted while abutting against the first portion 11.

The second portion 12 is provided at one end of the first portion 11 and a plurality of second portions 12 may be provided in a straight line as illustrated in Figure 2, It is not limited. The second portion 12 is made of a material that is relatively flexible as compared to the first portion 11. Accordingly, the second portion 12 is bent in accordance with the movement of the gantry 20 connected to one end of the second portion 12, and can provide bending between the gantry motors 20.

Figure 3 shows a specific embodiment of the second part described above.

As described above, the second portion 12 is made of a relatively flexible material and is bent in accordance with the movement of the gantry 20. In other words, the second part may be composed of a material having a degree of hardness of less than a certain value. At this time, the coupling angle between the gull motors 20 can be adjusted through the thickness of the second portion 12.

As shown in Fig. 3, it can be seen that the second portion 12 of (a) is made relatively thinner than the second portion 12 of (b). By varying the thickness of the second portion 12, a desired shape can be produced under specific conditions.

Specifically, as the second portion 12 is formed thicker, the movable range of the gantry 20 is reduced, resulting in a greater coupling angle between the gantry motors 20. On the other hand, the thinner the second portion 12 is formed, the greater the movable range of the gull synchronizer 20 is, and consequently the coupling angle between the gull motors 20 becomes small. It is possible to adjust the angle of engagement between the gull motors 20 through the adjustment of the thickness of the second portion 12 and as a result this makes it possible to produce a specific desired shape using the core 10 and the gull synchronizer 20 .

Figure 4 is a diagram showing the need for a core.

Suppose that the shape to be obtained according to the shape change of the flywheel 20 in a specific condition is (a). If there is no core 10, the gull synchronizer 20 is bent under a specific condition, and only the shape shown in (b) can be formed. However, when the core 10 is formed between the gull motors 20 as shown in (c), the gull motors 20 are bent around the core 10 to form a desired coupling angle. Therefore, the core 10 can be appropriately disposed according to a desired shape to form a desired shape.

(a) is a structure of a gantry synchronizer 20 according to the first embodiment of the present invention. 5 (a), the gantry synchronizer 20 according to the first embodiment is continuously printed with layers made of two different materials having different shrinkage ratios under specific conditions.

For example, the gantry synchronizer 20 according to the first embodiment may be composed of a plurality of layers, in which a plurality of successive layers have a non-expanding portion 21 having no hydrogel characteristic and a non- (22), respectively. Here, the hydrogel property refers to the property of expanding when exposed to liquids such as water or alcohol. Therefore, the gull synchronizer 20 according to the first embodiment is bent in accordance with the difference in shrinkage ratio between the non-expanding portion 21 and the expanding portion 22 when exposed to the liquid flow. In addition to this structure, it is possible to think of a linearly expanding structure. For reference, if there is no linearly expanding structure, a long trajectory can not be obtained as shown in FIG. 4-c.

At this time, the degree of bending can be adjusted according to the configuration of the non-expanding portion 21 and the expanding portion 22. For example, as the expansion ratio between the non-expanding portion 21 and the expanding portion 22 is increased, the bending angle between the gull motors 20 can be increased. Or the thickness ratio between the non-expandable portion 21 and the expanded portion 22 may be adjusted to adjust the bending angle between the gull motors 20.

Specifically, the non-expanding portion 21 does not have a hydrogel property and does not expand even when exposed to a liquid flow. On the other hand, the expanding portion 22 has a hydrogel characteristic and expands when exposed to liquids. As a result, only the expanding portion 22 expands when exposed to the liquid flow, and the actuator according to the first embodiment is bent.

(b) is a structure of the gantry synchronizer 20 according to the second embodiment of the present invention. 5 (b), the gantry synchronizer 20 according to the second embodiment includes a non-expanding portion 21 having a rectangular shape and an expanding portion 22 (not shown) provided between the non-expanding portion 21 ). As described above, under the specific conditions, the false motors 20 are bent in accordance with the difference in shrinkage ratio between the non-expandable portion 21 and the expanded portion 22.

In the case of the second embodiment, the unexpanded portion 21 in the shape of a rectangular frame does not expand under certain conditions, but only the expanding portion 22 expands under certain conditions and the expanding portion 22 is bent in a specific direction. 5 (b), the unexpanded portion 21 is shown as a rectangular frame, but the shape of the nonexpanded portion 21 is not limited to that shown in FIG. 5 (b), and a frame having another shape is also possible.

At this time, the degree of bending can be adjusted by the constitution of the expanding portion (22). For example, when the material having a high expansion ratio is used for the expanding portion 22, the expanding portion 22 can be bent relatively more, and in the opposite case, the expanding portion 22 can be bent relatively less.

The four-dimensional printing design method is a design method considering deformation of a three-dimensional printing structure, and is a method of designing a three-dimensional printing structure of a pre-deformation plane in a specific condition.

The shape to be printed can be shaped into a mesh, which is a collection of a myriad of consecutive triangles, and the mesh contains innumerable vertices and edges. The more vertices and edges there are, the more sophisticated the design can be, but the computational cost may increase.

First, a boundary is extracted from a shape to be printed (S101). Here, as described above, the boundary can serve as a frame in the four-dimensional printing as a portion that is not deformed under certain conditions.

It is determined whether the extracted boundary is flat (S103). Specifically, it is determined whether or not the boundary extracted from the 3D shape to be produced is a flat surface.

In one embodiment, if the extracted boundary is not plane, a convex polygon is generated (S105).

In another embodiment, if the extracted boundary is a plane, a weighting matrix for a vertex of a triangle forming a mesh is defined (S107).

The triangles forming the mesh of the three-dimensional shape are planarized using the weight matrix (S109). Specifically, an operation of setting the z value of the x, y, and z values of the vertices to 0 is performed using a weighting matrix. For more information on planarization, see M. Botsch et al., Polygon Mesh Processing (2010).

It is checked whether all the triangles are flattened (S111).

In a case where all the triangles are planarized in one embodiment, the degree of LE (Length Expansion Factor) that the edges of the plane mesh should expand to have a three-dimensional shape to be produced is calculated (S113). In this case, the LE can be obtained by comparing the edges of the planarized mesh with the edges before planarization.

At this time, it is determined whether or not an edge whose LE is smaller than 0 exists (S115).

In the case of four-dimensional printing using an expansion material according to an embodiment of the present invention, the material may exist only when the material is expanded more than the original and LE is larger than 0. Therefore, if LE is less than 0, it is necessary to correct it.

In one embodiment, if the LE is less than zero, the weight matrix is readjusted (S117). The re-adjustment of the weighting matrix is possible by a method of correcting a specific value to a weighting matrix used in the past. And the weights are re-adjusted until the LE of all edges has a positive value (LE> 0). Specifically, the coordinate of the vertex can be changed by the re-adjusted weight, and the LE when the triangle formed by the vertices of the changed coordinates is planarized can be calculated again to determine whether the LE for all the edges is larger than 0 .

The present invention described above can be embodied as computer-readable codes on a medium on which a program is recorded. The computer readable medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of the computer readable medium include a hard disk drive (HDD), a solid state disk (SSD), a silicon disk drive (SDD), a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, , And may also be implemented in the form of a carrier wave (e.g., transmission over the Internet). Also, the computer may include a control unit 180 of the terminal. Accordingly, the above description should not be construed in a limiting sense in all respects and should be considered illustrative. The scope of the present invention should be determined by rational interpretation of the appended claims, and all changes within the scope of equivalents of the present invention are included in the scope of the present invention.

Claims

In a four-dimensional printing structure that deforms itself under certain conditions,

Boundaries that do not deform under certain conditions;

A motive element provided in the boundary and deforming under a specific condition; And

And a core connecting the plurality of gull motors or the boundary,

Wherein the core adjusts the bending angle of the action period according to the deformation of the gantry

Four-dimensional printing structure.
The method according to claim 1,

The actuator

A first layer that expands under certain conditions and a second layer that does not expand under certain conditions are formed as a double layer

Four-dimensional printing structure.
The method according to claim 1,

The actuator

And is provided so as to surround a first portion that expands under certain conditions and a second portion that does not expand the first portion under certain conditions

Four-dimensional printing structure.
The method according to claim 1,

Wherein the core comprises a third portion comprised of a relatively rigid material and a fourth portion comprised of a material relatively flexible relative to the third portion

Four-dimensional printing structure.
5. The method of claim 4,

And one surface of the fourth portion corresponds to the shape of the third portion

Four-dimensional printing structure.
A method for designing a four-dimensional printing structure that changes from a specific condition to a desired shape,

A method of designing a planar three-dimensional structure including a boundary that does not deform under a specific condition, a core that connects a plurality of gull motors or a boundary to a boundary,

The core is designed to adjust the bending angle of the period of motion different from the deformation of the gantry

Four Dimensional Printing Structure Design Method.
The method according to claim 6,

The step of designing the actuator includes:

Designing the expanding portion expanding under a specific condition and the nonexpansion expanding portion not expanding under a specific condition into a double layer, respectively

Four Dimensional Printing Structure Design Method.
8. The method of claim 7,

The step of designing the actuator

Adjusting the ratio between the thickness of the inflating portion and the thickness of the non-inflating portion to adjust the degree of bending of the gantry

Four - Dimensional Priding Structural Design Method.
The method according to claim 6,

The step of designing the actuator

Designing to surround a first portion that expands under certain conditions and a second portion that does not expand the first portion under certain conditions

Four Dimensional Printing Structure Design Method.
10. The method of claim 9,

The step of designing the actuator

Adjusting the rate of material deforming under specific conditions included in the first portion to adjust the degree of bending of the gantry

Four Dimensional Printing Structure Design Method.
The method according to claim 6,

The step of designing the core

Comprising the step of designing the core to include a third portion comprised of a relatively rigid material and a fourth portion comprised of a material relatively flexible relative to the third portion

Four Dimensional Printing Structure Design Method.
12. The method of claim 11,

The step of designing the core

And adjusting the thickness of the fourth portion to adjust the degree of bending of the gantry

Four Dimensional Printing Structure Design Method.
The method according to claim 6,

As a method of designing a three-dimensional structure in which a desired shape is flattened,

Extracting a boundary from a desired shape;

Defining a weighting matrix for a vertex of a triangle forming a mesh for a desired pattern if the extracted boundary is a plane;

Flattening the triangle using the weighting matrix;

Computing a first value that is such that when all triangles are flattened, the triangle forming the mesh of the planes must be expanded to become the desired shape;

Determining whether the first value is less than zero; And

If the first value is less than zero, re-adjusting the weighting matrix until the first value is less than zero

Four Dimensional Printing Structure Design Method.