KR102092767B1 - Apparatus and method of printing active variable structure - Google Patents

Abstract

Disclosed herein is an active variable structure printing method. An embodiment of the present application, a nozzle formed to extrude a filament of a shape memory material on a predetermined bed, a temperature control unit formed to adjust the temperature of the nozzle to a temperature range in which the permanent shape of the filament is maintained, and , It provides an active variable structure printing apparatus including a nozzle control unit configured to control the speed at which the nozzle extrudes the filament and the moving speed of the nozzle to tension the extruded filament.

Description

Active variable structure printing device and method {APPARATUS AND METHOD OF PRINTING ACTIVE VARIABLE STRUCTURE}

The present invention relates to an active variable structure printing device and method, and more specifically, an active variable structure printing device and method capable of outputting a structure capable of restoring appearance after being output using a shape memory material as a filament of a 3D printer. It is about.

A 3D printer (hereinafter referred to as a 3D printer) means a machine that creates a 3D three-dimensional object based on an input drawing such that a 2D printer (2D printer) prints letters or pictures. Typical 3D printing methods applied to a 3D printer include a selective laser sintering (SLS) printing method and a fused deposition modeling (FDM) printing method. The SLS printing method refers to a method of forming a shape while solidifying a powder 물질 type material, and since the printer to which the SLS printing method is applied is very expensive, a relatively inexpensive FDM printing method is widely used.

Referring to FIG. 1 showing an example of the FDM printing method, the FDM printing method is an output method of extruding a filament-like material through a nozzle based on the power of an extruding motor and stacking the extruded output on the bed one by one. to be. At this time, according to the relative movement between the pre-programmed nozzle and the bed, the output has a pre-designed shape.

Meanwhile, so-called 4D printing technology, which performs 3D printing using a material capable of self-deformation, has recently grown into one field of 3D printer technology. In other words, a technique that allows 3D printed output to move on its own is called 4D printing. 4D printing has the advantage of simplifying the output shape compared to the final shape because it changes the shape of the output to the final shape, unlike the conventional 3D printing, which requires only the output of the desired result. Accordingly, 4D printing can realize a complex shape and save time and material for printing. 4D printing is used in biomedical and electronic fields that require shape change after printing.

4D printing, which is a technical field in which 3D printed outputs move by themselves, inevitably uses a smart material, which is the material that itself acts as a driver because the material itself must act as a driver. Among them, 4D printing research using a shape memory polymer is actively conducted. The shape memory resin is a polymer that remembers a specific shape in the early stage and returns to the original shape (shape memory effect) when an appropriate external stimulus such as heat is applied even after the shape transformation occurs.

In the case of the shape memory resin, it is not a material that generates force by itself, but a material that is driven by storing and releasing internal stress caused by an external force. Therefore, in the case of the conventional 4D printing technology using a shape memory resin, a process of applying an external force to the output is essential in order to restore the appearance of the output in the printing process. In addition to silk-shaped memory, 4D printing technology that allows an output to have energy from an output stage has not yet existed. Therefore, the implementation of this technology is recognized as one of the biggest challenges in the field of 4D printing.

The present invention has been devised to solve the above problems, and the technical problem to be achieved by the present invention is to print out an output capable of restoring its appearance by external stimulation by tensioning the shape memory material and outputting it in a pre-deformed state. It is to provide an active variable structure printing apparatus and method.

The technical problems to be achieved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by those skilled in the art from the following description. There will be.

In order to solve the above technical problem, an embodiment of the present invention, in a three-dimensional printer, the nozzle is formed to extrude the filament of the shape memory material on a predetermined bed, and the temperature range in which the permanent shape of the filament is maintained The temperature control unit is formed to control the temperature of the nozzle, and the speed at which the nozzle extrudes the filament and the movement speed of the nozzle according to the movement of the nozzle to control the filament in which the nozzle is melted is an internal stress ( It provides an active variable structure printing apparatus including a nozzle control unit formed to print in a form having a pre-strain.

In this embodiment, the filament is formed of a shape memory resin, and the polymer chain of the shape memory resin has a hard segment series to maintain the original state and a soft segment series that is fixed or deformed based on the transition temperature. The temperature control unit may be formed to control the temperature of the nozzle to be equal to or higher than the transition temperature of the soft segment series of the polymer chain within a range of the temperature range of the crosslinking of the hard segment series of the polymer chain.

In this embodiment, the filament is formed of a shape memory resin, and the polymer chain of the shape memory resin has a hard segment series to maintain the original state and a soft segment series that is fixed or deformed based on the transition temperature. The nozzle control unit controls the speed at which the nozzle extrudes the filament and the moving speed of the nozzle according to the movement of the nozzle, so that the nozzle internal stress (pre -strain) can be formed to print.

In this embodiment, the speed at which the nozzle extrudes the filament is formed in a direction perpendicular to the predetermined bed, and the moving speed of the nozzle is formed in a direction parallel to the predetermined bed, and the nozzle control unit is the It may be formed to control the moving speed greater than the speed of extruding the filament.

In this embodiment, the nozzle control unit may be formed to control the ratio of the speed of extruding the filament to the moving speed from 0.1 to 0.9.

In this embodiment, the shape memory material is formed of a shape memory resin, and the three-dimensional printer can extrude the filament by a melt lamination modeling method.

In addition, another embodiment of the present invention to solve the above technical problem, in a printing method using a three-dimensional printer including a nozzle, a temperature control unit and a nozzle control unit, (a) as a shape memory material having a specific permanent shape The step of injecting the filament to be formed into the nozzle, and (b) the temperature control unit melting the filament by adjusting the temperature of the nozzle to a temperature range in which the permanent shape of the filament is maintained, and (c) The nozzle control unit controls the speed of extruding the filament and the movement speed of the nozzle according to the movement of the nozzle, so as to print the molten filament in a form having an internal stress (pre-strain). Provided is a method for printing a variable structure.

In this embodiment, the filament is formed of a shape memory resin, and the polymer chain of the shape memory resin has a hard segment series to maintain the original state and a soft segment series that is fixed or deformed based on the transition temperature. The step (b) may be a step of adjusting the temperature of the nozzle to a transition temperature of the soft segment series of the polymer chain within a range of the crosslinking retention temperature of the hard segment series of the polymer chain.

In this embodiment, the filament is formed of a shape memory resin, and the polymer chain of the shape memory resin has a hard segment series to maintain the original state and a soft segment series that is fixed or deformed based on the transition temperature. In the step (c), the nozzle control unit controls the speed at which the nozzle extrudes the filament and the moving speed of the nozzle according to the movement of the nozzle, so that the nozzle is pre-deformed and melts the hard segment of the polymer chain. It may be a step of printing the filament in a state having an internal stress (pre-strain).

In this embodiment, the speed at which the nozzle extrudes the filament is formed in a direction perpendicular to the predetermined bed, and the moving speed of the nozzle is formed in a direction parallel to the predetermined bed, and step (c). The step may be a step in which the nozzle control unit controls the moving speed to be greater than the speed at which the filament is extruded so that the tensioned filament is extruded.

In this embodiment, step (c) may be a step of controlling the ratio of the speed at which the nozzle control unit extrudes the filament to the moving speed to 0.1 to 0.9 to extrude the tensioned filament.

In the present embodiment, the shape memory material is formed of a shape memory resin, and step (c) controls the speed at which the nozzle control unit extrudes the filament and the moving speed of the nozzle so that the stretched filament is extruded. However, it may be a step of extruding the filament in a melt lamination modeling method.

According to the present invention, by extruding the shape memory material pre-deformed above the transition temperature of the soft segment within a range capable of maintaining the crosslinking of the hard segment, the output can have energy from the output stage, and the output is simultaneously extruded. It can be made to have internal stress automatically.

In addition, according to the present invention, it is possible to control the shape memory material that has been previously deformed to enable the design and output of sophisticated outputs.

In addition, according to the present invention, by extruding the pre-deformed shape memory material, the appearance of the print can be restored without a separate post-processing process such as a process of applying an external force to the print, and a sophisticated print design and output can be performed. The printing process is simplified and the production time and cost of the printout can be saved.

It should be understood that the effects of the present invention are not limited to the above-described effects, and include all effects that can be deduced from the configuration of the invention described in the detailed description or claims of the present invention.

1 is a diagram illustrating a conventional FDM 3D printer.
2 is a block diagram showing a schematic configuration of a 3D printer according to an embodiment of the present invention.
3 is a view for explaining in detail the control method of the nozzle control unit according to an embodiment of the present invention.
4 is a view showing in detail to explain the output process and properties of the filament according to an embodiment of the present invention.
FIG. 5 is a graph showing a relationship between the strain and temperature of the filament according to an embodiment of the present invention, and the relationship between the strain of the filament and the ratio of the extrusion speed to the moving speed of the nozzle.
6 is a graph showing a graph of strain of an output according to a strain of a filament and a graph of strain of an output according to an output temperature according to an embodiment of the present invention.
7 is a flowchart illustrating a procedure of a 3D printing method according to another embodiment of the present invention.
8 is a view for explaining the appearance of the printed output according to embodiments of the present invention and a state in which the output is restored by heating the output.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. However, the present invention may be implemented in various different forms, and thus is not limited to the embodiments described herein. In addition, the accompanying drawings are only for easy understanding of the embodiments disclosed in the present specification, and the technical spirit disclosed in the specification is not limited by the accompanying drawings, and all modifications included in the spirit and technical scope of the present invention It should be understood to include water, equivalents or substitutes. In addition, in order to clearly describe the present invention in the drawings, parts irrelevant to the description are omitted, and the size, shape, and shape of each component shown in the drawings may be variously modified, and the same / similar parts for the entire specification The same / similar reference numerals are attached.

The suffixes "modules" and "parts" for the components used in the following description are given or mixed only considering the ease of writing the specification, and do not have meanings or roles distinguished from each other in themselves. In addition, in the description of the embodiments disclosed herein, when it is determined that detailed descriptions of related known technologies may obscure the gist of the embodiments disclosed herein, detailed descriptions thereof are omitted.

Throughout the specification, when a part is "connected (connected, contacted, or coupled)" with another part, this means that other members in the middle, as well as when "directly connected (connected, contacted or coupled)" Also included is a case in which they are "indirectly connected (connected, contacted, or combined)" between them. Also, when a part is said to "include (equipment or provision)" a component, it does not exclude other components unless specifically stated to "include (equipment or provision)" other components. It means you can.

The terms used in this specification are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions, unless the context clearly indicates otherwise, and distributed components may be implemented in a combined form unless otherwise specified. In this specification, terms such as “include” or “have” are intended to indicate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, and that one or more other features are present. It should be understood that the existence or addition possibilities of fields or numbers, steps, operations, components, parts or combinations thereof are not excluded in advance.

2 is a block diagram showing a schematic configuration of an active variable structure printing device (hereinafter referred to as “printing device 10”) according to an embodiment of the present invention.

2, the printing apparatus 10 is formed to include a nozzle 11, a temperature control unit 12 and a nozzle control unit 13.

The nozzle 11 is formed to extrude (or discharge) the filament of the shape memory material on a predetermined bed. The filament of the molten shape memory material may be injected into the nozzle 11, and the size of the discharge port of the nozzle 11 may be variously formed, for example. For example, the size of the discharge port may be formed to a size equal to or less than the diameter of the filament formed of the shape memory material. Here, the shape memory material may be a shape memory resin.

The temperature control unit 12 is formed to control the temperature of the nozzle 11 and / or the filament in a temperature range in which the permanent form of the filament is maintained. Preferably, the temperature control unit 12 may be formed to adjust the temperature of the nozzle 11 and / or the filament to 140 ° C to 190 ° C.

The nozzle control unit 13 controls the speed at which the nozzle 11 extrudes the filament and the moving speed of the nozzle according to the movement of the nozzle, thereby pre-straining the filament in which the nozzle 11 is melted. It is formed to print in the form having a. Here, the shape having an internal stress (pre-strain) means a state in which a filament formed of a shape memory material is pre-deformed and stretched, and has an internal stress to return to a permanent shape.

In this regard, the shape memory resin described in detail herein has the property of maintaining the network structure of the preformed polymer. In addition, the shape memory resin has a shape memory effect to return to the memorized permanent shape even if it is transformed into a temporary shape by external force due to these properties.

The process of deforming the shape memory resin from a permanent shape to a temporary shape is performed by applying an external force at a glass transition temperature (for example, about 55 ° for DiaPLEX) of the shape memory resin. The shape memory resin is in a solid state below the glass transition temperature, and then undergoes a glass transition temperature to change to a rubber state, showing a sharp decrease in stiffness.

When the temperature is increased, the shape memory resin forms a new network structure and loses the previously memorized permanent shape. According to various embodiments of the present invention, pre-deformation (tensile) is applied by mechanically stretching the shape memory resin in a memorized state. In the process, when a new permanent form of a new shape memory resin is formed, the nature of returning to the original length disappears.

More specifically, the polymer chain of the shape memory resin (Polymer Chain) is a hard segment series having the property of maintaining the original state by crosslinking of the polymer and a soft segment that is fixed or deformed based on the transition temperature ( soft segment), that is, it is composed of two separate domains. For the expression of the shape memory effect, a processing process of forming a crosslink and a programming process of forming a new shape from a formed shape are necessary. The programming procedure follows the following procedure.

First, the shape memory resin is heated to a transition temperature or higher, so that the soft segment becomes a fluid phase capable of shape deformation, thereby enabling molding by external force. Next, after shaping by applying an external force to the shape memory resin, the shape memory resin is cooled below the transition temperature of the soft segment so that the shape memory resin can be fixed in a state in which pre-deformation is applied to the hard segment. When the shape memory resin programmed in this way is heated above the transition temperature, the soft segment is converted into a fluid phase, and by the resilience of the hard segment, the molded shape returns to the main shape formed by crosslinking.

Accordingly, in various embodiments of the present invention, a temperature lower than the temperature used in the conventional 3D printing may be used to prevent the temperature from being excessively high and thus a new crosslinked structure is formed and the original memorized shape is lost. However, it is necessary to control the temperature of the filament to an appropriate temperature since an extrusion failure problem may occur when the filament of the shape memory material is output at a temperature that is too low.

For example, in the present embodiment, when the filament is formed of a shape memory resin, as described above, the polymer chain of the shape memory resin is a soft segment that is fixed or deformed based on a series of hard segments and transition temperatures to maintain the original state. It has a series. At this time, the temperature control unit 12 may be formed to control the temperature of the nozzle 11 to be higher than the transition temperature of the soft segment series of the polymer chain within the temperature range of the crosslinking retention of the hard segment series of the polymer chain. .

In addition, in the above example, the nozzle control unit 13 controls the speed at which the nozzle 11 extrudes the filament and the moving speed of the nozzle according to the movement of the nozzle, so that the nozzle 11 is hard in the polymer chain. The segment may be pre-deformed to print the filament in a molten state in a form having an internal stress (pre-strain).

On the other hand, the present invention can be extruded filaments by a melt deposition modeling (Fused Deposition Modeling, FDM) method, but is not limited thereto. In addition, all filaments having a shape memory effect as well as the shape memory resin described above can be applied to the present invention.

3 is a view for explaining a control method of the nozzle control unit 13 in detail.

라고 정의했을 때, 본 발명에서는 의도적으로

의 값을 높임으로써 출력물을 기계적으로 인장시킬 수 있다.

의 값이 커지면 커질수록 출력물이 늘어나는 정도(Stretched rate)가 늘어나며, 그 결과 출력물의 변형률 또한 커지게 된다. 본 발명은 이를 이용해 출력 중에

의 값을 변화시키며 출력물에 인가되는 사전 변형의 정도를 원하는 대로 조절할 수 있다. For ease of understanding, the moving speed of the nozzle relative to the extrusion speed of the filament is a dimensionless variable.

When defined as, in the present invention,

The output can be mechanically tensioned by increasing the value of.

The larger the value of, the greater the stretched rate of the output, and as a result the strain of the output also increases. The present invention uses this during output

By changing the value of, the degree of pre-deformation applied to the output can be adjusted as desired.

Referring to FIG. 3, the nozzle control unit 13 controls the speed 31 at which the nozzle 11 extrudes the filament and the moving speed 32 of the nozzle 11 according to the movement of the nozzle 11, thereby controlling the nozzle ( 11) This is formed to extrude the tensioned filament. Here, the speed 31 at which the nozzle 11 extrudes the filament may be formed in a direction perpendicular to the predetermined bed, and the moving speed 32 of the nozzle 11 may be formed in a horizontal direction with the predetermined bed.

Also, the nozzle control unit 13 may be formed to control the moving speed 32 larger than the extrusion speed 31. Specifically, the nozzle control unit 13 may be formed to control the ratio (speed ratio) of the extrusion speed 31 (extrusion speed / travel speed) with respect to the movement speed 32 to 0.1 to 0.9. The speed ratio will be described in more detail with reference to FIG. 5 below.

In this way, the printing device 10 can extrude the pre-deformed shape memory material so that the output has energy from the output stage, and can automatically have internal stress at the same time as the output is extruded. The printing device 10 may control the shape memory material that has been pre-deformed to enable the design and output of sophisticated prints.

4 is a view showing in detail to explain the output process and properties of the filament according to an embodiment of the present invention.

Referring to FIG. 4, in the 41 corresponding to the state immediately before extrusion, the filament is melted while remembering the permanent shape. Next, in the 42 corresponding to the state immediately after extrusion, the filament is a state in which the internal stress is generated by the external force application (tensile) of the nozzle control unit 13. Next, in the output completion state 43, as the filament is cooled, there is a holding state in which internal stress is not exerted. Next, when the filament output by an external stimulus such as heating releases an internal stress, the filament returns to the shape of the permanent shape that was originally memorized.

FIG. 5 is a graph showing a relationship between the strain and temperature of the filament according to an embodiment of the present invention, and the relationship between the strain of the filament and the ratio of the extrusion speed to the moving speed of the nozzle.

As described above, if the temperature of the nozzle is too low, the extrudate of the hardened filament will block the nozzle, resulting in poor extrusion, and if the temperature of the nozzle is too high, the shape memory effect that the filament will return to the previously memorized permanent shape will have. Will disappear. Therefore, as shown in the graph of 51 shown in FIG. 5, the temperature control unit 12 needs to properly adjust the temperature of the nozzle. Accordingly, the temperature control unit 12 of the printing device 10 adjusts the temperature of the nozzle 11 to 140 ° C to 190 ° C so that the filament does not lose its shape memory effect and does not cause extrusion problems. You can.

In addition, the lower the speed ratio, that is, the lower the filament extrusion speed compared to the moving speed of the nozzle, the higher the pre-deformation (tensile). This also produces unstable output when the speed ratio is too low. Therefore, as shown in the graph of 51 shown in FIG. 5, the nozzle control unit 13 needs to maintain a constant speed ratio, and as described above, the nozzle control unit 13 determines the ratio of the extrusion speed to the moving speed. It may be formed to control from 0.1 to 0.9.

6 is a graph showing the experimental results according to an experimental example of the present invention, 61 is a graph showing a strain change of the final output according to the stretched rate (stretched rate), 62 is the output according to the output temperature It shows a graph of the strain change.

Referring to 61 of FIG. 6, it can be seen that as the nozzle control unit 13 increases the ratio of pre-deformation, the strain rate of the final output also increases. In addition, referring to 62 of FIG. 6, it can be seen that the strain of the output differs depending on the output temperature, and if it is too high, cross-linking retention of the hard segment of the filament may be broken, whereas when the output temperature is too low, extrusion It can be seen that problems with defects may occur.

Based on FIGS. 1 to 6 described above, a detailed experimental example according to this embodiment will be described below.

With regard to equipment and materials, in this experimental example, a commercial shape memory resin filament (DiAPLEX, SMP Technologies Inc.) was output to a commercial FDM 3D printer (CORE200, a manufacturing tool) to produce a 3D output with pre-deformation applied.

The properties of the material (shape resin filament DiAPLEX) have a melting point of about 210 ° C., a glass transition temperature of about 55 ° C., and a diameter of 1.75 mm.

Even if other equipment and materials are selected, if the diameters are compatible with each other, mutual equivalents may be used. However, when the material (shape retardant filament) is different and the characteristic temperature such as melting point and glass transition temperature is different, it should be output according to the temperature corresponding to the material.

In this example, the diameter of the nozzle was processed larger than usual (3 mm) for easier output. For the resolution of the 3D printer, a small diameter nozzle must be used, so the process of increasing the diameter of the nozzle can be omitted.

With regard to the output conditions of this example, the material is output at a temperature lower than the melting point (210 ° C in this example), but extrusion may not work properly at too low a temperature. Did. Accordingly, in this experiment example, the output was examined at a temperature between 140 ° C and 200 ° C to examine the change in strain, and when changing the extrusion speed, the experiment was performed while being fixed at 150 ° C. In addition, in this experiment, the moving speed of the nozzle was fixed at 150 mm / min, and the extrusion speed was changed to 22.5 mm / min, 45 mm / min, 135 mm / min, 180 mm / min, 225 mm / min, 450 mm / min, etc. I looked at the changes. When experimenting while changing the temperature, the experiment was performed with the extrusion speed fixed at 99 mm / min. In addition, the distance between the nozzle and the bed was experimented while being fixed at 0.3 mm, and the temperature of the bed was set to room temperature without setting separately.

In the printing process of this example, two lines of 75mm to 95mm are printed with the distance between the bed and the nozzle being 0.3mm with a 3mm nozzle, but when overlapped by 0.4mm for adhesion (75 ~ 95) mm × 5.6mm × A specimen of 0.3 mm was prepared.

The operating conditions of this experimental example were set to heat for 10 minutes in a natural convection oven at a temperature of about 70 ° C, which is higher than the glass transition temperature (about 55 ° C).

The operation results of this experimental example are shown in the following tables.

Table 1 below experiments while changing the temperature, but the moving speed of the nozzle is 150 mm / min, the extrusion speed is 99 mm / min, the distance between the nozzle and the bed is 0.3 mm, and the bed temperature is fixed at room temperature. It shows.

number Temperature Length after printing Length after heating Amount of change Strain T (℃) mm mm mm % 1-1 140 91 55 36 39.56 1-2 140 91 56 35 38.46 1-3 140 90 54 36 40.00 1-4 140 92 56 36 39.13 1-5 140 92 56 36 39.13 3-1 150 90 62 28 31.11 3-2 150 91 61 30 32.97 3-3 150 91 62 29 31.87 3-4 150 89 62 27 30.34 3-5 150 90 60 30 33.33 2-1 160 90 64 26 28.89 2-2 160 91 65 26 28.57 2-3 160 91 65 26 28.57 2-4 160 92 66 26 28.26 2-5 160 91 66 25 27.47 3-1 170 91 73 18 19.78 3-2 170 91 72 19 20.88 3-3 170 92 73 19 20.65 3-4 170 90 70 20 22.22 3-5 170 91 71 20 21.98 4-1 180 92 79 13 14.13 4-2 180 92 79 13 14.13 4-3 180 92 78 14 15.22 4-4 180 92 79 13 14.13 4-5 180 92 79 13 14.13 5-1 190 93 85 8 8.60 5-2 190 91 81 10 10.99 5-3 190 92 82 10 10.87 5-4 190 92 82 10 10.87 5-5 190 92 82 10 10.87 6-1 200 93 87 6 6.45 6-2 200 92 85 7 7.61 6-3 200 92 85 7 7.61 6-4 200 90 83 7 7.78 6-5 200 91 84 7 7.69

Table 2 below experiments while changing the extrusion speed, but the moving speed of the nozzle is 150mm / min, the output temperature is 150 ℃, the distance between the nozzle and the bed is 0.3mm, and the temperature of the bed is fixed at room temperature. This is the result of the example.

number Extrusion speed Length after printing Length after heating Amount of change Strain Λ (mm / min) mm mm mm % 1-1 22.5 92 49 43 46.74 1-2 22.5 90 46 44 48.89 1-3 22.5 90 47 43 47.78 1-4 22.5 89 47 42 47.19 1-5 22.5 89 48 41 46.07 2-1 45 85 50 35 41.18 2-2 45 90 52 38 42.22 2-3 45 91 52 39 42.86 2-4 45 91 50 41 45.05 2-5 45 91 51 40 43.96 3-1 135 92 61 31 33.70 3-2 135 91 63 28 30.77 3-3 135 90 61 29 32.22 3-4 135 89 61 28 31.46 3-5 135 92 63 29 31.52 4-1 180 90 66 24 26.67 4-2 180 90 66 24 26.67 4-3 180 89 65 24 26.97 4-4 180 91 66 25 27.47 4-5 180 91 66 25 27.47 5-1 225 89 65 24 26.97 5-2 225 88 63 25 28.41 5-3 225 88 62 26 29.55 5-4 225 88 64 24 27.27 5-5 225 88 64 24 27.27 6-1 450 93 82 11 11.83 6-2 450 91 82 9 9.89 6-3 450 90 81 9 10.00 6-4 450 88 78 10 11.36 6-5 450 88 79 9 10.23

As described with reference to FIG. 6, it can be seen through the results according to this experimental example that the strain of the output varies depending on the output temperature, and the strain of the output differs depending on the ratio of the extrusion speed to the moving speed.

In addition, referring to FIG. 8 shown to describe the appearance of the printed output according to the embodiments of the present invention and the appearance of the output restored by heating, the length of the output specimen as shown in 801 is about 3 cm, but after heating The length of the restored specimen is about 1.8 cm, and it can be seen that the length of the output changes when the outer shape is restored by heating 1.2 cm. In addition, it can be seen that the shape of the output is flat, but the shape changes when the output is restored by heating the output, thereby forming a three-dimensional petal shape. In addition, as shown in 803, it can be seen that the shape of the output is changed to a flat shape or a shape surrounding an object in the center when the output is restored by heating the output.

7 is a flowchart showing a procedure of an active variable structure printing method according to another embodiment of the present invention, the printing method according to this embodiment is a printing using the printing device 10 described with reference to Figures 1 to 6 above It is a way. That is, all functions and procedures performed by the printing device 10 may be included as a process in the printing method described below. Therefore, hereinafter, descriptions overlapping with the above-described contents will be omitted.

The active variable structure printing method according to the present embodiment is a printing method using a 3D printer including a nozzle, a temperature controller and a nozzle control unit, (a) the filament formed of a shape memory material having a specific permanent shape is the nozzle Step (S71) to be injected, and (b) the temperature control unit to melt the filament by adjusting the temperature of the nozzle to a temperature range in which the permanent shape of the filament is maintained (S72), and (c) the And controlling the speed at which the nozzle control unit extrudes the filament and the moving speed of the nozzle to print the filament in which the nozzle is melted in a form having an internal stress (pre-strain) (S73).

Here, the speed at which the nozzle extrudes the filament may be formed in a direction perpendicular to the predetermined bed, and the moving speed of the nozzle may be formed in a direction horizontal to the predetermined bed.

In addition, step (b) (S72) may be a step of melting the filament by adjusting the temperature of the nozzle to 140 ° C to 190 ° C by the temperature control unit.

In addition, step (c) (S73) may be a step in which the nozzle control unit controls the movement speed to be greater than the speed at which the filament is extruded so that the extruded filament is stretched.

In addition, step (c) (S73) may be a step of controlling the ratio of the speed at which the nozzle control unit extrudes the filament to the moving speed to 0.1 to 0.9 so that the extruded filament is stretched.

In addition, step (c) (S73) is a step in which the nozzle control unit controls the speed of extruding the filament and the moving speed of the nozzle so that the extruded filament is tensioned, and extruding the filament by a melt lamination modeling method. Can be

In addition, as described above, in the present embodiment, the filament is formed of a shape memory resin, and the polymer chain of the shape memory resin is a soft segment that is fixed or deformed based on a hard segment series and a transition temperature to maintain the original state. Take the case of having a series as an example. At this time, (b) step (S72), the temperature control unit, the temperature of the nozzle is adjusted to the transition temperature of the soft-segment series of the polymer chain within the cross-linking retention temperature range of the hard segment series of the polymer chain It may be a step. In addition, in the same example, (c) step (S73), the nozzle control unit, the nozzle to control the speed of extruding the filament and the movement speed of the nozzle according to the movement of the nozzle, the nozzle is the polymer It may be a step of printing the filament in a state in which the hard segment of the chain is pre-deformed and melted in a form having an internal stress (pre-strain).

As described above, when the printing method according to the present embodiment is used, the appearance of the output can be restored without a separate post-treatment process such as a process of applying an external force to the output by extruding the shape memory material that has been pre-deformed (tensile) The design and printing of prints are possible, which simplifies the process of 4D printing and saves the manufacturing time and cost of prints.

The above description of the present invention is for illustration only, and those of ordinary skill in the art to which the present invention pertains can understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the following claims, and all changes or modifications derived from the meaning and scope of the claims and equivalent concepts should be interpreted to be included in the scope of the present invention.

Claims (12)

For a 3D printer,
A nozzle formed to extrude a filament of shape memory material into a predetermined bed;
A temperature control unit formed to control the temperature of the nozzle in a temperature range in which the permanent form of the filament is maintained; And
The ratio of the speed at which the nozzle extrudes the filament and the speed at which the nozzle extrudes the filament by controlling the moving speed of the nozzle according to the movement of the nozzle is changed during extrusion of the filament to be applied to the output. It includes a nozzle control unit to control the pre-strain to print the filament in which the nozzle is melted in a form having an internal stress,
The filament is formed of a shape memory resin, the polymer chain of the shape memory resin has a hard segment series to maintain the original state and a soft segment series that is fixed or deformed based on the transition temperature,
The temperature control unit is formed to adjust the temperature of the nozzle to a transition temperature of the soft segment series of the polymer chain within a range of the crosslinking retention temperature range of the hard segment series of the polymer chain,
The nozzle control unit is an active variable structure printing device, characterized in that the nozzle is formed to print the filament in a molten state in a form having a pre-strain by pre-straining the hard segment of the polymer chain.
delete delete According to claim 1,
The speed at which the nozzle extrudes the filament is formed in a direction perpendicular to the predetermined bed, and the moving speed of the nozzle is formed in a direction parallel to the predetermined bed,
The nozzle control unit is an active variable structure printing device, characterized in that formed to control the movement speed greater than the speed of extruding the filament.
According to claim 1,
The nozzle control unit is an active variable structure printing device, characterized in that formed to control the ratio of the speed of extruding the filament to the moving speed from 0.1 to 0.9.
According to claim 1,
The three-dimensional printer is an active variable structure printing apparatus, characterized in that extruding the filament in a melt-laminated modeling method.
In the printing method using a three-dimensional printer including a nozzle, a temperature control unit and a nozzle control unit,
(A) a filament formed of a shape memory material having a specific permanent shape is injected into the nozzle;
(b) melting the filament by adjusting the temperature of the nozzle to a temperature range in which the temperature control unit maintains the permanent shape of the filament; And
(c) the nozzle control unit extrudes the filament at a ratio of the speed at which the nozzle extrudes the filament and the speed at which the nozzle extrudes the filament by controlling the moving speed of the nozzle according to the movement of the nozzle And controlling the pre-deformation applied to the output by changing during the process so that the nozzle prints the molten filament in a form having internal stress,
The filament is formed of a shape memory resin, the polymer chain of the shape memory resin has a hard segment series to maintain the original state and a soft segment series that is fixed or deformed based on the transition temperature,
The step (b) is a step in which the temperature control unit adjusts the temperature of the nozzle to a transition temperature of the soft segment series of the polymer chain within a range of the crosslinking retention temperature of the hard segment series of the polymer chain,
In the step (c), the nozzle control unit is characterized in that the nozzle is a step in which the hard segment of the polymer chain is pre-deformed to print the filament in a molten state in a form having an internal stress (pre-strain). Active variable structure printing method.
delete delete The method of claim 7,
The speed at which the nozzle extrudes the filament is formed in a direction perpendicular to the predetermined bed, and the moving speed of the nozzle is formed in a direction parallel to the predetermined bed,
The (c) step is an active variable structure printing method, characterized in that the step of controlling the nozzle so that the moving speed is greater than the speed of extruding the filament so that the tensioned filament is extruded.
The method of claim 7,
The (c) step is an active variable structure printing method, characterized in that the step of controlling the ratio of the speed at which the nozzle extrudes the filament to the moving speed is 0.1 to 0.9 to extrude the tensioned filament.
The method of claim 7,
The step (c) is characterized in that the nozzle control unit controls the speed of extruding the filament and the moving speed of the nozzle so that the stretched filament is extruded, but extruding the filament in a melt lamination modeling method. Active variable structure printing method.

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