3D printing method for constant line width

Abstract

The present invention relates to a 3D printing method for a constant line width, the line width being constant even when only one layer is stacked when a discharged material is stacked, and a 3D structure being able to be clearly printed. The method is characterized by comprising the following steps that a synthetic high polymer material contained in an injector is ejected onto a printing bed through a nozzle in an extrusion mode and stacked; in order to produce a thin discharge layer, the nozzle is suspended from the discharged lower layer material to a certain height. A 3D structure is manufactured by printing in such a manner that the material discharged through the nozzle is placed on the lower layer.

Description

Technical Field

[0001] The present invention relates to a 3D printing method for constant line width, and more particularly to a 3D printing method for constant line width, wherein spitted material is stacked in a direction intersecting with the material of the lower layer, so that the line width is constant and a 3D structure can be clearly printed. Background Art

[0002] 3D printing is a technology for molding three-dimensional structural products. It can not only mold three-dimensional structures quickly, but also has the advantage of being able to produce shapes that cannot be assembled or disassembled. Formal research on this type of 3D printing has been going on for a long time. In the past, due to the limited materials that can be printed and the expensive equipment, it was not widely used and was only used in limited fields such as the production of aerospace-related parts or prototype production of automobiles. However, it has recently been tried to be widely used in many fields, and its application area is expanding.

[0003] 3D printing technology is roughly divided into the following methods and implemented: Fused Deposition Modeling (FDM) using solid materials, Stereolithography Apparatus (SLA) using liquid materials and Digital Lighting Processing (DLP), Selective Laser Sintering (SLS) using powder materials, etc.

[0004] In 3D printing technology, FDM is a method that melts solid materials, makes them like metal wires, and outputs them through a nozzle. Compared with other methods, its advantages are that it can achieve low-cost 3D printing and output in various colors.

[0005] In the case of the existing FDM method, the material is molded into a very thin layer for shape precision and surface precision. The thickness of the ejected material is smaller than the ejection nozzle diameter, and at this time, the nozzle ejects while pressing the material.

[0006] Previous printing methods such as Figure 1 As shown, the nozzle 21 is located at the thickness of the layer stacked on the upper part of the printing bed 10, and then the material contained in the syringe 20 is extruded by the nozzle 21 to press and print the stacked material m. Figure 4 As shown, when the material m-1 ejected from the nozzle 21 is ejected along the same axial direction as the material m of the lower layer, the material m of the lower layer is pressed, as shown in FIG. Figure 2As shown, the cross section of the material m stacked on the printing bed 10 and the cross section of the material m-1 ejected through the nozzle 21 are different from each other. Figure 3 As shown, on an overhang structure (the space between the material m-1 that must be ejected and the ejected material m or the space outside the ejected material m), it is not easy to eject without support, and when ejecting, it is difficult to eject the material in a form with a constant line width while the material of the lower layer sinks, and it is not easy to produce it in the form of a clear 3D structure.

[0007] In addition, the disadvantages of the previous printing method are: Figure 3 and Figure 4 As shown, the lower layer material and the spitted material are cross-printed in the same axial direction, so that the lower layer material and the spitted material are placed in the same direction, so the overhang printing method itself is difficult, and this stacking is the printing of the extrusion stacking method (FDM), and the materials encountered at the intersection are aggregated or guided by viscosity, such as Figure 5 and Figure 6 As shown, the line width of the printed material has changed.

[0008]

Prior technical literature

[0009] (Patent Document 0001) Korean Patent Publication No. 10-2022-0036205 Summary of the invention

[0010] Therefore, the present invention is proposed to solve the above-mentioned problems, and its purpose is to provide a 3D printing method for constant line width. When stacking materials through a nozzle, the nozzle is suspended at a certain height from the ejected lower layer material, and the material is ejected along an axial direction different from the lower layer material, so as to print in a manner of placing the material on the lower layer, and thus placed on the upper part of another layer in an overhang structure printing manner, thereby keeping the line width constant and printing uniform lines, and clearly forming pores, thereby improving the quality of the 3D structure.

[0011] In order to achieve the above-mentioned purpose, a 3D printing method for constant line width according to an embodiment of the present invention may include the following steps: a synthetic polymer material contained in a syringe is extruded through a nozzle onto a printing bed and stacked; in order to produce a thin extruded layer, the nozzle is suspended to a certain height from the lower layer of the extruded material; and the material extruded through the nozzle is printed in a manner of placing it on the lower layer, thereby producing a 3D structure.

[0012] In the step of suspending the nozzle at a certain height from the ejected lower layer material, the distance between the lower layer material and the ejected material may be set to be less than twice the line width of the ejected material.

[0013] In the step of printing by placing the material ejected through the nozzle on the lower layer to produce a 3D structure, the ejected material can be ejected along an axial direction different from that of the material of the lower layer.

[0014] In the step of printing by placing the material ejected through the nozzle on the lower layer to produce a 3D structure, the produced 3D structure can have a three-dimensional double void structure with a void ratio of less than 50%.

[0015] In the step of printing by placing the material ejected through the nozzle on the lower layer to produce a 3D structure, the synthetic polymer material printing conditions can be set to an ejection pressure of less than 700 kPa, a material heating temperature of less than 300°C, and a nozzle transfer speed of less than 2,000 mm / min.

[0016] In the step of printing by placing the material ejected through the nozzle on the lower layer to make a 3D structure, the nozzle movement speed can be set to a speed less than 100% of the movement speed before the axis change when the moving axis moves a short distance after the axis change.

[0017] As described above, according to the 3D printing method for constant line width of the present invention, after the nozzle is suspended from the ejected lower layer material to a certain height, the ejected material is ejected along an axial direction different from the lower layer material, placed on the lower layer material, and printed in this way so as to be placed on the upper part of another layer, thereby the line width of the ejected material is constant, and each line is printed evenly to obtain a precise 3D structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 FIG. 1 is a diagram showing an example of a conventional printing method.

[0019] Figure 2 This is a cross-sectional view of the material that is deposited and the material that is ejected from the nozzle when printing is performed using a conventional printing method.

[0020] Figure 3 It is a cross-sectional view showing a state according to a conventional printing process.

[0021] Figure 4 It is a plan view showing a state according to a conventional printing process.

[0022] Figure 5 This is an enlarged image of the surface of a planar structure produced by a conventional printing method.

[0023] Figure 6This is an enlarged image of the surface of a cylindrical structure produced by a conventional printing method.

[0024] Figure 7 is an exemplary diagram illustrating a 3D printing process for a constant line width according to the present invention.

[0025] Figure 8 is a perspective view showing a process of a 3D printing method for a constant line width according to the present invention.

[0026] Fig. 9 is a plan view showing a process state through a 3D printing method for a constant line width according to the present invention.

[0027] Fig.10 is a cross-sectional view showing materials stacked and materials ejected through a nozzle when printing with the 3D printing method for a constant line width according to the present invention.

[0028] Fig.11 This is an image of a surface of a planar structure produced by the 3D printing method for a constant line width according to the present invention.

[0029] Fig.12 This is an enlarged image of the surface of a cylindrical structure produced by the 3D printing method for constant line width according to the present invention.

[0030] Fig.13 is a sequence diagram showing a 3D printing method for a constant line width according to the present invention.

[0031] Description of symbols

[0032] 100: Print bed

[0033] 200: Syringe

[0034] 210: Nozzle DETAILED DESCRIPTION

[0035] The present invention can be modified in many ways and has many embodiments, so specific embodiments are illustrated in the drawings and described in detail in the specification. However, this is not intended to limit the specific implementation of the present invention, but should be understood to include all changes, equivalents and even substitutes within the scope of the present invention.

[0036] According to the drawings, the embodiments of the present invention are not limited to the specific forms shown in the drawings, but are exaggerated for clarity. Specific terms are used in this specification, but they are only used to illustrate the present invention and are not used to limit the meaning or the scope of the rights of the present invention recorded in the patent claims.

[0037] In this specification, the expression "and / or" is used to mean that at least one of the constituent elements listed before and after is included. In addition, the expression "connected / combined" means directly connected to other constituent elements or indirectly connected through other constituent elements. In this specification, the singular also includes the plural, unless otherwise specifically mentioned in the sentence. In addition, the constituent elements, steps, actions and components "including" or "including..." used in the specification mean that one or more other constituent elements, steps, actions and components exist or are added.

[0038] In the description of the embodiments, the description that each layer (film), region, pattern or structure is formed "on" or "under" the substrate, each side (film), region, pad or pattern includes being formed directly or with the intervention of other layers. The reference of the upper / upper or lower / underside of each layer is described with reference to the accompanying drawings.

[0039] Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail.

[0040] Figure 7 is an example diagram showing a 3D printing process for a constant line width according to the present invention, Figure 8 is a perspective view showing a process of a 3D printing method for a constant line width according to the present invention, Fig. 9 is a plan view showing a process state of a 3D printing method for a constant line width according to the present invention, Fig.10 is a cross-sectional view showing materials stacked and materials ejected through a nozzle when printing with a 3D printing method for a constant line width according to the present invention, Fig.11 is an image of the surface of a planar structure produced by the 3D printing method for constant line width according to the present invention, Fig.12 is an image of the surface of a cylindrical structure produced by the 3D printing method for constant line width according to the present invention, which is magnified and photographed. Fig.13 is a sequence diagram showing a 3D printing method for a constant line width according to the present invention.

[0041] According to the 3D printing method for constant line width of the present invention, synthetic polymers are used as printing materials. The materials contained in the syringe 200 can be discharged through the nozzle 210 while being stacked and manufactured into a 3D structure through an overhang printing method.

[0042] like Figures 7 to 13As shown, the 3D printing method for constant line width according to the present invention may include the following steps: spitting the material contained in the syringe 200 through the nozzle 210 on the printing bed 100 in an extruded manner and stacking, wherein a 3D structure is printed on the printing bed 100 S100; in order to produce a thin spit layer that is stacked after spitting, the nozzle 210 is suspended from the spitted lower layer material m to a certain height S200; and printing in a manner of placing the material m-1 spitted out through the nozzle 210 on the lower layer material m, thereby producing a 3D structure S300.

[0043] At this time, the material to be printed and stored in the syringe 200 may be a synthetic polymer. Preferably, the synthetic polymer is a thermoplastic polymer.

[0044] Preferably, the synthetic polymer is one or more selected from the group consisting of caprolactone, dioxanone, glycolide, lactide, propylene, ethylene, trimethylene, vinyl chloride, butadiene, methyl methacrylate, carbonate, acrylic acid, 2-hydroxyethyl methacrylate, and polyethylene terephthalate. In addition, preferably, the synthetic polymer is one or more selected from the group consisting of granule type, powder type, and filament type.

[0045] In step S200 of suspending the nozzle 210 to a certain height from the discharged lower material m, the height of the lower material m and the nozzle 210 can be set to a height equal to or less than the diameter of the nozzle 210. The distance d between the lower material m and the discharged material m-1 can be set to be less than 2 times the line width of the discharged material m-1.

[0046] The diameters of the materials m and m-1 stacked on the printing bed 100 are formed to be equal to or smaller than the diameter of the nozzle 210 that spits out the materials, and the material m-1 is spouted out in a state where the nozzle 210 is suspended from the material m of the lower layer to a certain height, so that the distance d between the material m of the lower layer and the material m-1 spouted out from the nozzle 210 can be formed to be equal to or smaller than the diameter of the nozzle 210. In other words, as an example, Figure 7As shown, if the diameter of the nozzle 210 is 300 μm, the diameter of the lower stacked material m is 300 μm, and the distance d between the lower material m and the material m-1 ejected through the nozzle 210 may be 2 to 300 μm.

[0047] like Figures 8 to 9 As shown, in the step S300 of printing by placing the material m-1 ejected by the nozzle 210 on the lower layer to make a 3D structure, the material m-1 ejected on the upper part of the lower layer can be ejected along an axial direction different from the material m of the lower layer. Therefore, the ejected material m-1 is ejected along an axial direction different from the material m of the lower layer and is placed on the upper part of another layer, thereby forming a constant line width.

[0048] On the other hand, preferably, the axial directions of the lower layer material m and the discharged material m-1 are all directions except 0° or 180°, but are not limited thereto.

[0049] In other words, Fig.11 and Fig.12 As shown, when the overhang printing method is applied not only to planar structures but also to rods that can make cylindrical structures, if the ejected material m-1 is printed on the underlying material m, the line width of all parts can be confirmed to be constant regardless of the overhang structure.

[0050] In the step S300 of printing by placing the material m-1 ejected by the nozzle 210 on the lower layer material m, the 3D structure produced may have a three-dimensional double void structure with a void ratio of less than 50%. At this time, the void ratio (%) of the 3D structure can be calculated by V-(M / p) / V×100 (V represents the total volume of the 3D structure, M represents the mass, and p represents the density).

[0051] As mentioned above, Fig.11 As shown in (a) and (b), it can be confirmed that the 3D structure manufactured by material extrusion has a three-dimensional shape. Fig.11 As shown in (c) and (d), it can be confirmed that even if only one layer is stacked, the line width can be formed to be very constant, and the grid pattern has a form with lines and spaces.

[0052] In addition, preferably, the printing conditions for making 3D structures are that the discharge pressure of the materials m and m-1 discharged from the nozzle 210 is less than 700 kPa, preferably, the heating temperature of the materials m and m-1 is set to be lower than 300°C, and the transfer speed of the nozzle 210 is set to be lower than 2,000 mm / min. When setting the transfer speed of the nozzle 210, it can be set to a speed of less than 100% of the transfer speed before the axis change when the moving axis moves a short distance after the axis change.

[0053] The 3D structure is manufactured by repeatedly discharging materials m-1, ..., mn while the nozzle 210 is suspended to a certain height from the lower layer of the material m being discharged.

[0054] As described above, a 3D structure is printed by stacking materials m and m-1 composed of synthetic polymers on the printing bed 100. At this time, the nozzle 210 is suspended to a certain height from the lower layer material m ejected on the printing bed 100, and printing is performed in a manner such that the material m-1 ejected by the nozzle 210 is placed at a position higher than the thickness of the ejected lower layer material m.

[0055] In addition, the material m-1 ejected from the upper portion of the lower layer material m is ejected and stacked in an axial direction different from that of the lower layer material m, and is placed on the upper portion of another layer to form a constant line width in all portions.

[0056] Therefore, after the nozzle 210 is suspended from the lower layer, the ejected material m-1 is placed on the lower layer material m in the cross direction, and printing is performed in this way, so that even if only one layer is stacked on the lower layer material m, the line width can be printed constantly. In addition, in a state where the nozzle 210 is suspended from the lower layer material m to a certain height, printing is performed in a manner of placing the material m-1 on the lower layer material m, so that the cross-sections of the stacked material m and the material m-1 ejected by the nozzle 210 are formed to be the same, thereby printing uniform lines with a clear 3D structure, and forming clear pores.

[0057] In the above detailed description of the present invention, only the corresponding specific embodiments are described. However, it should be understood that the present invention is not limited to the specific forms mentioned in the detailed description, but should be understood to include all variants, equivalents and substitutes within the spirit and scope of the present invention defined by the claims.

[0058] In other words, the present invention is not limited to the specific embodiments and descriptions described above, and any person having general knowledge in the technical field to which the present invention belongs may make various modifications without departing from the gist of the present invention as claimed in the claims, and such modifications are within the scope of protection of the present invention.

Claims

1. A 3D printing method for constant line width, characterized in that: The steps include: The synthetic polymer material contained in the syringe is extruded through the nozzle onto the printing bed and stacked; To make a thin spit layer, the nozzle is suspended to a certain height from the lower spit material; as well as Printing is done by placing the material ejected from the nozzle on top of the underlying layer to create a 3D structure.

2. The 3D printing method for constant line width according to claim 1, characterized in that: In the step of suspending the nozzle to a certain height from the ejected lower layer material, the distance between the lower layer material and the ejected material is set to be less than twice the line width of the ejected material.

3. The 3D printing method for constant line width according to claim 1, characterized in that: In the step of printing in such a manner that a material ejected through a nozzle is placed on a lower layer to produce a 3D structure, the ejected material is ejected in an axial direction different from that of the material of the lower layer.

4. The 3D printing method for constant line width according to claim 1, characterized in that: In the step of printing by placing the material ejected through the nozzle on the lower layer to produce a 3D structure, the produced 3D structure has a three-dimensional double void structure and a void ratio of less than 50%.

5. The 3D printing method for constant line width according to claim 1, characterized in that: In the step of printing by placing the material ejected through the nozzle on the lower layer to produce a 3D structure, the synthetic polymer material printing conditions are set to an ejection pressure of less than 700 kPa, a material heating temperature of less than 300°C, and a nozzle transfer speed of less than 2,000 mm / min.

6. The 3D printing method for constant line width according to claim 1, characterized in that: In the step of printing by placing the material ejected through the nozzle on the lower layer to produce a 3D structure, the nozzle transfer speed is set to a speed less than 100% of the transfer speed before the axis change when the moving axis moves a short distance after the axis change.

7. The 3D printing method for constant line width according to claim 1, characterized in that: The diameter of the material stacked on the print bed is formed to be the same as or smaller than the diameter of the nozzle that discharges the material.

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