3D PRINTING APPARATUS AND 3D PRINTING METHOD

Abstract

To provide a three-dimensional printing device that can increase a strength between layers that make up a modeling object.SOLUTION: A three-dimensional printing device forms a modeling object composed of a plurality of layers of a photocurable ink, and comprises: an application unit that accumulates the plurality of layers; and a light irradiation unit that irradiates a layer with light to semi-cure a surface layer area of the deposited layers each time the plurality of layers are deposited and to completely cure an internal area other than the surface layer area.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a three-dimensional printing apparatus and a three-dimensional printing method. [Background technology]

[0002] Three-dimensional printing (3D printing) generally refers to a technique for producing three-dimensional objects through a process of depositing material layer by layer. In many embodiments, 3D printing techniques utilize one or more processes that can be considered similar to known processes for forming two-dimensional (2D) printed images on a stage.

[0003] Although 3D printing techniques may utilize processes similar to 2D printing processes, there are two notable differences between them: the first is the composition of the deposition material used to form the object, and the second is the multiple movements of the nozzle dispensing the deposition material above the stage as multiple layers of the deposition material are deposited.

[0004] Some 3D printing techniques use techniques such as selective laser melting or sintering to melt or soften the deposited material to produce layers. Other 3D printing techniques use techniques for depositing liquid materials, such as stereolithography, which are then hardened. Other 3D printing techniques, such as thin film deposition, create features by cutting and joining thin layers of paper, polymers, or metals in layers.

[0005] Three-dimensional printing devices can generally print a wide range of different deposition materials. For example, a technique using ultraviolet (UV) light-curable inks containing a high concentration of solid components in solution is known (see, for example, U.S. Patent No. 5,399,336). Deposition materials that can be applied to three-dimensional printing devices include, for example, extruded plastics, thermoplastics, high-density polyethylene, certain metals (including sintered metals, metal powders and / or metal alloys), adhesive powder mixtures, ceramic materials, ceramic matrix composites, modeling clay, gypsum, and certain ink-like materials including light-curable inks containing a high concentration of solid components in solution. Three-dimensional printing devices can also be used to deposit layers of edible material compositions to produce food products. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2016-159629 A Summary of the Invention [Problem to be solved by the invention]

[0007] In normal 2D printing, the adhesion between the coating layer and the printed object is important. In 3D printing, the material is deposited in layers, so the adhesion between each layer is important. However, the adhesion strength at the interface of each layer is weaker than the bulk strength of the material within the layer. Therefore, structures produced using a general 3D printing device usually have lower impact strength in the direction perpendicular to the deposition direction compared to the deposition direction of the material. Therefore, it cannot be used in general applications that require a certain level of strength against impacts from all directions, which is one of the factors preventing the expansion of 3D printing applications.

[0008] In view of the above circumstances, the present disclosure aims to provide a three-dimensional printing apparatus and a three-dimensional printing method that can increase the strength between the layers that make up a model. [Means for solving the problem]

[0009] The three-dimensional printing device disclosed herein is a three-dimensional printing device that forms a model composed of multiple layers of photocurable ink, and includes an application unit that deposits the multiple layers, and a light irradiation unit that irradiates light each time the multiple layers are deposited with light to semi-cure a surface region of the deposited layer and to completely cure an internal region other than the surface region. an irregularity forming unit that forms irregularities on the surface of the layer before the light is irradiated; Equipped with. The three-dimensional printing device disclosed herein is a three-dimensional printing device that forms a model composed of multiple layers of photocurable ink, and includes an application unit that deposits the multiple layers, a light irradiation unit that irradiates light to semi-cure a surface region of the deposited layer each time the multiple layers are deposited and to completely cure an internal region other than the surface region, and an irradiation control unit, wherein the light irradiation unit includes a plurality of light sources, and the irradiation control unit divides the multiple light sources into two or more groups and irradiates light of different light intensities for each of the two or more groups, thereby varying the semi-cured state of the regions in the surface region where the light of different light intensities is irradiated, and forms first surface divided regions and second surface divided regions having different semi-cured states alternately along a direction perpendicular to the deposition direction of the multiple layers. The three-dimensional printing device disclosed herein is a three-dimensional printing device that forms a model composed of multiple layers of photocurable ink, and includes an application unit that deposits the multiple layers, and a light irradiation unit that irradiates light to semi-cure a surface region of the deposited layer and completely cure an internal region other than the surface region each time the multiple layers are deposited, and each time a first ink and a second ink are alternately ejected in the horizontal direction to deposit the multiple layers, the light irradiation unit irradiates light onto a first region made of the first ink to semi-cure the surface region of the first region and completely cure the internal region of the first region other than the surface region, and irradiates light onto a second region made of the second ink to completely cure the entire second region. In addition, the three-dimensional printing apparatus disclosed herein is a three-dimensional printing apparatus that forms a model composed of multiple layers of photocurable ink, and includes an application unit that deposits the multiple layers, and a light irradiation unit that irradiates light to semi-cure a surface region of the deposited layer and completely cure an internal region other than the surface region each time the multiple layers are deposited, and when forming an outer frame of the model, a product portion inside the outer frame, and a connection portion connecting the outer frame and the product portion, the light irradiation unit semi-cures a surface region of the deposited layer corresponding to the outer frame and the product portion each time the multiple layers are deposited, and completely cures the internal region other than the surface region to form the outer frame and the product portion, and each time the multiple layers are deposited, completely cures a region of the deposited layer corresponding to the connection portion to form the connection portion.

[0010] The three-dimensional printing method disclosed herein is a three-dimensional printing method for forming a model, comprising the steps of: depositing a plurality of layers of a photocurable ink; and, each time the plurality of layers are deposited, irradiating the deposited layers with light to semi-cure a surface region of the deposited layer and completely cure an internal region other than the surface region. forming projections and recesses on the surface of the layer before the light is irradiated; Includes. Effect of the Invention

[0011] According to the 3D printing apparatus and 3D printing method disclosed herein, it is possible to increase the strength between the layers that make up the object. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a side view of a three-dimensional printing apparatus according to a first embodiment of the present disclosure. [Diagram 2] FIG. 11 is a side view of a three-dimensional printing apparatus according to a second embodiment of the present disclosure. [Diagram 3] Graph showing the relationship between the wavelength and intensity distribution of the light irradiated by a metal halide lamp according to a second embodiment of the present disclosure. [Figure 4] FIG. 13 is a side view of a three-dimensional printing apparatus according to a third embodiment of the present disclosure. [Diagram 5] FIG. 13 is a side view of a three-dimensional printing apparatus according to a fourth embodiment of the present disclosure. [Figure 6] FIG. 13 is a side view of a three-dimensional printing apparatus according to a fifth embodiment of the present disclosure. [Figure 7] FIG. 13 is a plan view of a main part of a three-dimensional printing device according to a sixth embodiment of the present disclosure. [Figure 8] FIG. 13 is a side view of a three-dimensional printing apparatus according to a seventh embodiment of the present disclosure. [Figure 9] FIG. 13 is a side view of a three-dimensional printing apparatus according to an eighth embodiment of the present disclosure. [Figure 10] FIG. 23 is a side view showing a state after a modeling process of a modeled object according to a ninth embodiment of the present disclosure. [Figure 11] FIG. 23 is a side view of a structure according to a tenth embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present disclosure will be described. Note that the configurations of the first to tenth embodiments described below can be combined within a feasible range.

[0014] [First embodiment] First, a first embodiment of the present disclosure will be described. Fig. 1 is a side view of a three-dimensional printing device according to the first embodiment of the present disclosure.

[0015] <Configuration of 3D printing device> 1, the three-dimensional printing apparatus 1 includes a coating unit 101, a light irradiation unit 102, a stage 103, and a temperature control unit 104. The coating unit 101, the light irradiation unit 102, the stage 103, and the temperature control unit 104 are disposed inside a printing chamber 100.

[0016] The application unit 101 includes a nozzle 101A that applies a photocurable ink (hereinafter, sometimes referred to as "ink") 150. An inkjet head, a dispenser, an electrostatic applicator, a spray, or a die coater can be used as the application unit 101. Note that the ink used in the first embodiment and the second to tenth embodiments described below is cured by UV light and heat, but the ink used in the embodiments other than the fifth embodiment may be cured by UV light only.

[0017] The light irradiation unit 102 includes a light source 102A that emits UV light (ultraviolet light) L1, which is an example of light. As the light source 102A, a UV lamp such as a mercury lamp or a metal halide lamp can be used.

[0018] The stage 103 is disposed below the coating unit 101 and the light irradiation unit 102. The stage 103 moves in the horizontal direction and the up-down direction by driving a stage driving unit (not shown). The stage 103 moves in the horizontal direction in synchronization with the ejection timing of the coating unit 101 in order to land the ink 150 ejected from the coating unit 101 at a predetermined position on the stage 103 or the model 170. The stage 103 moves away from the coating unit 101 in order to adjust the gap between the model 170 and the coating unit 101 according to the progress of the formation of the model 170. The stage 103 and the stage driving unit may be substituted by a belt conveyor, a robot hand, or the like. The three-dimensional printing device 1 may be configured to move the coating unit 101 while fixing the stage 103, or to move both the stage 103 and the coating unit 101.

[0019] The temperature control unit 104 controls the temperature inside the printing chamber 100, particularly the temperature around the layer of ink 150, so that the reproducibility of the cured state of a surface region 151 of the layer of ink 150 deposited on the stage 103 and the cured state of a region (internal region) 152 other than the surface region 151 is not lost due to the temperature inside the printing chamber 100. When the difference between the temperature inside the printing chamber 100 detected by the temperature sensor 104A and the set temperature is equal to or greater than a threshold value, the temperature control unit 104 supplies cold or hot air into the printing chamber 100 to eliminate the temperature difference.

[0020] <3D printing method> First, a general three-dimensional printing method will be described. The application unit 101 continuously or intermittently ejects the ink 150 onto the stage 103, and the stage driving unit moves the stage 103 in the direction indicated by the arrow Y1, thereby depositing a layer of uncured ink 150 on the stage 103. While depositing the layer of ink 150, the light irradiation unit 102 irradiates the layer with UV light L1 to completely cure the uncured ink 150. Note that completely cured means a state in which the curing rate is 100%. For example, an acrylic ultraviolet curing resin can be selected as the ink 150. By repeating the formation of such a layer of uncured ink 150 and the complete curing of the uncured ink 150, a three-dimensional model 170 is formed. However, in such a three-dimensional printing method, as described above, the adhesion between each layer is insufficient.

[0021] Therefore, in the first embodiment, the light irradiation unit 102 controls the light intensity of the UV light L1 so that the ink 150 is cured to such an extent that it loses its fluidity and retains its tackiness. The curing rate of the ink 150 when irradiated with UV light L1 of such light intensity varies depending on the characteristics of the ink 150, but is preferably 40% to 95%, and more preferably 50% to 70%.

[0022] The ink 150 is inhibited from curing by oxygen contained in the surrounding air A. Therefore, the curing rate of the surface region 151 of the layer (ink layer) 160 of the ink 150 can be made lower than the curing rate of the inner region 152. Here, the surface region 151 is formed on the upper surface and side surface of the layer (ink layer) 160 of the ink 150 shown in FIG. 1. The surface region 151 having a low curing rate is in a state where it does not flow unless an external force is intentionally applied, and does not flow with a force of about the acceleration of gravity. The surface region 151 is in a state where it remains tacky and feels sticky when touched. This state is sometimes called semi-cured. When uncured ink 150 is deposited on the surface region 151 in this semi-cured state, an interface 153 can be formed in which the functional groups of the surface region 151 having a low curing rate and the functional groups of the uncured ink 150 are firmly bonded. When the interface 153 is irradiated with UV light L1 that semi-cures the surface region 151, the reaction at the interface proceeds without coming into contact with oxygen in the surrounding air A, and the interface is completely cured.

[0023] Next, a three-dimensional printing method in the first embodiment will be described. As in the general three-dimensional printing method described above, as shown in Fig. 1, the coating unit 101 and the stage driving unit deposit an ink layer 160 of ink 150 on the stage 103. During this deposition, the light irradiation unit 102 irradiates the uncured ink layer 160 with UV light L1, which semi-cures a surface region 151 of the ink layer 160 and completely cures an inner region 152.

[0024] Next, the coating unit 101 and the stage driving unit deposit the ink layer 161 of the uncured ink 150 on the semi-cured surface region 151. During this deposition, an interface 153 is formed where the functional groups of the semi-cured surface region 151 and the functional groups of the uncured ink layer 161 are firmly bonded. In addition, the light irradiation unit 102 irradiates the uncured ink layer 161 with UV light L1 to semi-cure the surface region 151 of the ink layer 161 and to completely cure the internal region 152. By irradiating the UV light L1, the semi-cured surface region 151 and the completely cured internal region 152 are formed in the uncured ink layer 161, which is the outermost layer. Furthermore, with the formation of the completely cured internal region 152, the semi-cured surface region 151 of the ink layer 160 in contact with the internal region 152 is also completely cured, and the interface 153 where the functional groups are firmly bonded is also completely cured. As a result, the strength between the layers constituting the model 170 is increased. Thereafter, the deposition of layers of uncured ink 150 and the irradiation of UV light L1 that semi-cures the surface region 151 of the ink 150 are repeated, thereby forming a model 170 having a predetermined shape. Note that, although the first to tenth embodiments describe a method of applying ink using an inkjet method, methods other than the inkjet method can also be used as the method of applying ink.

[0025] [Second embodiment] Next, a second embodiment of the present disclosure will be described. Fig. 2 is a side view of a three-dimensional printing device according to the second embodiment of the present disclosure. The three-dimensional printing device 2 of the second embodiment has the same configuration as the three-dimensional printing device 1 of the first embodiment, except that the light irradiation unit 202 is provided instead of the light irradiation unit 102. The light irradiation unit 202 differs from the light irradiation unit 102 of the first embodiment in that it includes an LED that irradiates UV light.

[0026] Conventionally, UV lamps are generally used as light sources for curing deposition materials in three-dimensional printing devices. Among them, metal halide lamps can irradiate broadband light. The wavelength of light irradiated by a general metal halide lamp is shown in FIG. 3. In a metal halide lamp, even if the main peak is 365 nm, there are also peaks below 300 nm and above 500 nm, resulting in a wide wavelength distribution. When light with such a wide wavelength distribution is irradiated, the layer of uncured ink 150, including the surface region 151, is in a state of high curing rate throughout. If an attempt is made to control the curing rate of ink 150 by controlling the light intensity of such light with a wide wavelength distribution, there is a risk that the curing rate cannot be controlled to a desired state due to the influence of output variations such as temperature at the time of start-up of the UV lamp and deterioration.

[0027] In the second embodiment, in consideration of the fact that light of a wide wavelength is necessary to completely cure the uncured ink 150 efficiently, the surface layer region 151 is stably controlled to a semi-cured state by light of a limited wavelength. Specifically, for example, the width of the wavelength of the UV light L2 can be limited by using a plurality of light sources 202A each composed of a UV-LED as the light source of the light irradiation unit 202. The plurality of light sources 202A are arranged in a line in a direction perpendicular to the paper surface of FIG. 2, and are configured to irradiate the UV light L2 to a linear region extending in the direction perpendicular to the paper surface. The light source 202A includes a plurality of light-emitting elements having different peak intensities. The light-emitting elements are composed of UV-LED elements. The peak wavelength of the light-emitting elements is determined for each element, such as 365 nm, 375 nm, 385 nm, 395 nm, 405 nm, etc. In the light source 202A, the output of each of these light-emitting elements can be adjusted. For example, the light source 202A can set the wavelength of the UV light L2 to a range of 300 nm to 450 nm, the peak light intensity to 385 nm, and the range in which the light intensity is reduced by half to ±10 nm from the peak. By irradiating the ink layer 161 of the uncured ink 150 with UV light L2 having such a narrow wavelength range, the surface region 151 can be controlled to a uniform semi-cured state.

[0028] The wavelength range of the UV light L2 depends on the ink, but is preferably in the range of 150 nm (=450 nm-300 nm) or less, and more preferably 100 nm or less. In addition, the light source 202A can select a predetermined value for the light intensity peak, for example, 365 nm or 395 nm, according to the photocuring characteristics of the deposition material, and can appropriately adjust the light intensity distribution. In addition, by using a UV-LED for the light source 202A, the size of the device can be made smaller than that of a method using a UV lamp.

[0029] [Third embodiment] Next, a third embodiment of the present disclosure will be described. Fig. 4 is a side view of a three-dimensional printing device according to the third embodiment of the present disclosure. Note that the same components as those of the three-dimensional printing device 2 of the second embodiment are given the same reference numerals and will not be described.

[0030] <Configuration of 3D printing device> As shown in FIG. 4, the three-dimensional printing apparatus 3 includes a coating unit 101, a light irradiation unit 202, a stage 103, and a hardening unit 305. The coating unit 101, the light irradiation unit 202, and the stage 103 are disposed inside a printing chamber (not shown). The temperature control unit 104 of the first embodiment is also disposed inside the printing chamber. The hardening unit 305 includes a metal halide lamp 305A. Note that, although not shown, each of the three-dimensional printing apparatuses in the following third to tenth embodiments is provided with a temperature control unit 104 and a printing chamber.

[0031] <3D printing method> The application unit 101, the light irradiation unit 202, and the stage driving unit perform the same operations as those in the second embodiment to form a molded object 170 having a predetermined shape. At the completion of this molding, the internal region 172 of the molded object 170 is composed of completely cured photocurable ink (ink), but the surface region 171 located on the upper surface and side surface of the internal region 172 is in a semi-cured state because curing is inhibited by oxygen when irradiated with UV light L2. Therefore, in the third embodiment, a post-curing process is performed after the completion of molding. In the post-curing process, the stage driving unit moves the stage 103 in the direction indicated by the arrow Y1, and when the molded object 170 passes under the post-curing processing unit 305, the post-curing processing unit 305 irradiates the molded object 170 with UV light L3 from the metal halide lamp 305A.

[0032] As described in the second embodiment, the UV light L3 from the metal halide lamp 305A has a broad wavelength band, and therefore can react with unreacted functional groups in the semi-cured surface region 171. As a result, the surface region 171 is completely cured, and the tackiness remaining on the top and side surfaces of the model 170 disappears. For process reasons, an additional curing device having an additional curing processing unit 305 can be provided as a device separate from the 3D printing device 3.

[0033] [Fourth embodiment] Next, a fourth embodiment of the present disclosure will be described. Fig. 5 is a side view of a three-dimensional printing device according to the fourth embodiment of the present disclosure. Note that the same components as those of the three-dimensional printing device 2 of the second embodiment are given the same reference numerals and will not be described.

[0034] <Configuration of 3D printing device> As shown in FIG. 5, the three-dimensional printing apparatus 4 includes a coating unit 101, a light irradiation unit 202, a stage 103, and an oxygen concentration control unit 405.

[0035] The oxygen concentration control unit 405 includes a gas supply unit 405A, an oxygen concentration meter 405B, and a mixed gas composition determination unit 405C.

[0036] The gas supply unit 405A includes a mixer 405D, an oxygen generator 405E, a nitrogen generator 405F, and a gas nozzle 405G. The oxygen generator 405E and the nitrogen generator 405F are connected in parallel to the inlet of the mixer 405D. The gas nozzle 405G is connected to the outlet of the mixer 405D. The mixer 405D discharges a mixed gas G4, which is a mixture of oxygen introduced from the oxygen generator 405E and nitrogen introduced from the nitrogen generator 405F, from the gas nozzle 405G disposed between the coating unit 101 and the light irradiation unit 202. The mixer 405D can generate a mixed gas G4 in any state in which the ratio of oxygen to nitrogen is between 0:100 and 100:0.

[0037] The oxygen concentration meter 405B is disposed near the light irradiation unit 202, and transmits the measured oxygen concentration data to the mixed gas composition determination unit 405C.

[0038] The mixed gas composition determination unit 405C acquires oxygen concentration data of the air around the light irradiation unit 202 from the oxygen concentration meter 405B. Based on the acquired oxygen concentration data, the mixed gas composition determination unit 405C controls the oxygen generator 405E and the nitrogen generator 405F to supply mixed gas G4 having a composition that controls the oxygen concentration of the air around the light irradiation unit 202 to a desired concentration, to the printing chamber.

[0039] <3D printing method> The application unit 101, the light irradiation unit 202, and the stage driving unit form the model 170 of a predetermined shape by the same operation as in the second embodiment. The three-dimensional printing method of the fourth embodiment is particularly useful when it is necessary to increase the light intensity of the UV light L2 for the reason of increasing the curing speed of the internal region 152 to improve the shape accuracy of the model 170. When it is desired to increase the light intensity of the UV light L2 and keep the surface region 151 in a semi-cured state, the oxygen concentration control unit 405 supplies the mixed gas G4 with a mixture ratio that increases the oxygen concentration, and actively increases the oxygen concentration of the air around the surface region 151. By increasing the oxygen concentration around the surface region 151 in this way, the curing of the surface region 151 is inhibited (suppressed) by oxygen, so that the semi-cured state of the surface region 151 is maintained even if the light intensity of the UV light L2 is increased. Finally, in the process of completely curing the semi-cured surface region of the model 170, mixed gas G4 with a mixture ratio in which the oxygen concentration is reduced is supplied while irradiating UV light L2 with the light intensity when the surface region 151 is semi-cured. This reduces the inhibition by oxygen when the surface region of the model 170 is cured, and allows the surface region to be completely cured. When implementing the three-dimensional printing method of the fourth embodiment, since there is a possibility that the oxygen concentration outside the three-dimensional printing apparatus 4 may be low, it is preferable to enclose and seal the three-dimensional printing apparatus 4 itself in a booth.

[0040] [Fifth embodiment] Next, a fifth embodiment of the present disclosure will be described. Fig. 6 is a side view of a three-dimensional printing device according to the fifth embodiment of the present disclosure. Note that the same components as those of the three-dimensional printing device 2 of the second embodiment are given the same reference numerals and will not be described.

[0041] <Configuration of 3D printing device> As shown in FIG. 6, the three-dimensional printing apparatus 5 includes a coating unit 101, a light irradiation unit 202, a coating stage 503, a curing stage 504, a stage driving unit 505, a transfer unit 506, and an additional curing unit 507.

[0042] A plate 508 is placed on the coating stage 503. The modeled object 170 is formed on the plate 508. The modeled object 170 is placed on the curing stage 504 via the plate 508. The curing stage 504 is used for the additional curing process in the additional curing processing unit 305. The stage driving unit 505 moves the coating stage 503 below the coating unit 101 and the light irradiation unit 202. The stage driving unit 505 moves the curing stage 504 in the horizontal direction inside the heating unit 507A, which is a thermal curing oven of the additional curing processing unit 507. The transfer unit 506 has a suction pad 506A, and holds the modeled object 170 via the plate 508 on the coating stage 503 by a method such as vacuum suction, and transfers it onto the curing stage 504.

[0043] <3D printing method> The coating unit 101, the light irradiation unit 202, and the stage driving unit 505 perform the same operations as those in the second embodiment to form a model 170 having a predetermined shape on a plate 508 placed on the coating stage 503. After the modeling is completed, the 3D printing apparatus 5 performs a post-curing process.

[0044] First, after the modeling of the object 170 is completed, the stage driving unit 505 moves the coating stage 503 below the transfer unit 506, and the transfer unit 506 holds and lifts the plate 508 on the coating stage 503. When the entrance shutter 507B of the heating unit 507A opens, the stage driving unit 505 moves the coating stage 503 in a direction away from the heating unit 507A, and moves the curing stage 504 in the heating unit 507A below the transfer unit 506. The transfer unit 506 places the plate 508 on the curing stage 504, thereby transferring the object 170 to the curing stage 504.

[0045] When the stage driving unit 505 moves the curing stage 504 into the heating unit 507A, an entrance shutter 507B of the heating unit 507A is closed. The heating unit 507A heats the model 170. This heating causes unreacted functional groups in the semi-cured surface region 171 to react, and the surface region 171 is completely cured. When the surface region 171 is completely cured, an exit shutter 507C of the heating unit 507A is opened, and the model 170 is removed by a robot or an operator. As described above, by using heating in the post-curing step, the initial cost of the equipment can be reduced compared to a method using UV light.

[0046] By introducing nitrogen into the heating unit 507A, it is possible to further promote complete curing of the surface region 171 and uniformly cure the entire modeled object 170. In addition, by disposing a stocker capable of storing multiple models 170 between the printing chamber in which the modeled object 170 is formed and the heating unit 507A, and configuring the heating unit 507A to be able to heat-treat multiple models 170 at once, it is possible to improve the productivity of the modeled object 170.

[0047] [Sixth embodiment] Next, a sixth embodiment of the present disclosure will be described. Fig. 7 is a plan view of a main part of a three-dimensional printing device according to the sixth embodiment of the present disclosure.

[0048] <Configuration of 3D printing device> The three-dimensional printing device 6 shown in FIG. 7 has the same configuration as the three-dimensional printing device 2 of the second embodiment, except that a light irradiation unit 602 and an irradiation control unit 603 are provided instead of the light irradiation unit 202. The light irradiation unit 602 includes a plurality of light sources 602A each configured with a UV-LED. The light sources 602A are arranged in a line in a direction perpendicular to the moving direction of the stage 103 indicated by the arrow Y1. The light sources 602A irradiate UV light of the same wavelength. The irradiation control unit 603 individually controls the on / off of the light sources 602A and the light intensity of the UV light. The irradiation control unit 603 divides the light sources 602A into two or more groups, and irradiates UV light of different light intensities for each of the two or more groups. In the sixth embodiment, the irradiation control unit 603 divides the multiple light sources 602A into two groups (a group that irradiates UV light of a first light intensity and a group that irradiates UV light of a second light intensity) as described below, but may divide the light sources 602A into three or more groups.

[0049] <3D printing method> The application unit, the irradiation control unit 603, and the stage driving unit form a shaped object 170 of a predetermined shape on the stage 103 by the same operation as in the second embodiment. When semi-curing the layer of the uncured ink 150, the irradiation control unit 603 controls the irradiation state of the multiple light sources 602A so that a light source 602A (hereinafter, sometimes referred to as a "first light source 602B") having a first light intensity of UV light and a light source 602A (hereinafter, sometimes referred to as a "second light source 602C") having a second light intensity of UV light stronger than the first light intensity are alternately arranged, as shown in FIG. 7. In addition, the irradiation control unit 603 switches the light intensity of the UV light of the multiple light sources 602A from the first light intensity to the second light intensity or from the second light intensity to the first light intensity at the same timing. In FIG. 7, the first light source 602B is represented by a circle, and the second light source 602C is represented by a double circle.

[0050] As described above, by controlling the light irradiation unit 602 and moving the stage 103 in the direction indicated by the arrow Y1, a semi-cured surface layer region 151 is formed on the shaped object 170. At this time, the region 151A (hereinafter sometimes referred to as the "first surface layer divided region 151A") irradiated with the UV light from the first light source 602B in the surface layer region 151 has a first curing rate, and the region 151B (hereinafter sometimes referred to as the "second surface layer divided region 151B") irradiated with the UV light from the second light source 602C has a second curing rate higher than the first curing rate. The first surface layer divided region 151A and the second surface layer divided region 151B are alternately formed along the direction indicated by the arrow Y1 and the direction perpendicular to the direction indicated by the arrow Y1. That is, the first surface layer divided region 151A and the second surface layer divided region 151B are formed in a staggered pattern. In FIG. 7, the first surface layer divided region 151A is represented by a filled square, and the second surface layer divided region 151B is represented by an unfilled square.

[0051] In the model 170 completed by the above method, the uncured ink layer is deposited on the first surface layer divided region 151A and the second surface layer divided region 151B, which have different curing rates, so that the interface between the semi-cured surface layer region 151 and the uncured ink layer formed thereon becomes even less clear, making it difficult for a fracture starting point to form against a force applied in a direction perpendicular to the deposition direction of the ink layer. This makes it possible to improve the durability of the model 170 against a force applied in a direction perpendicular to the deposition direction of the ink layer.

[0052] The intensity of the UV light from the light source 602A can also be varied by blinking the light source 602A. The intensity of the light source 602A may also be switched randomly.

[0053] In addition, because the direction of the force applied to the shaped object 170 is predetermined, or for production reasons, the first surface layer divided region 151A and the second surface layer divided region 151B may be formed in a striped pattern (vertical stripes or horizontal stripes in FIG. 7). In this case, examples of the method include a method in which the light source 602A functioning as the first light source 602B and the light source 602A functioning as the second light source 602C are fixed to form the first surface layer divided region 151A and the second surface layer divided region 151B in a striped pattern (horizontal stripes) parallel to the moving direction of the stage 103, and a method in which the light intensity of the UV light from all the light sources 602A is repeatedly switched between the first light intensity and the second light intensity at the same timing to form the first surface layer divided region 151A and the second surface layer divided region 151B in a striped pattern (vertical stripes) perpendicular to the moving direction of the stage 103.

[0054] [Seventh embodiment] Next, a seventh embodiment of the present disclosure will be described. Fig. 8 is a side view of a three-dimensional printing device according to the seventh embodiment of the present disclosure. Note that the same components as those of the three-dimensional printing device 2 of the second embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0055] <Configuration of 3D printing device> As shown in FIG. 8, the three-dimensional printing device 7 includes the coating unit 101, the light irradiation unit 202, the stage 103, and the unevenness forming unit 704. The unevenness forming unit 704 includes an unevenness forming roller 704A and a scraper 704B. The unevenness forming roller 704A is disposed between the coating unit 101 and the light irradiation unit 202. A plurality of protrusions 704C are provided on the surface of the unevenness forming roller 704A. The protrusions 704C are formed, for example, in a dot shape. The protrusions 704C may be linear. The protrusions 704C are formed to a height of, for example, 1 μm or more and 50 μm or less. The scraper 704B is disposed between the unevenness forming roller 704A and the light irradiation unit 202. Since the scraper 704B comes into contact with the protrusions 704C, it is desirable that the scraper 704B is formed of an elastic material such as rubber.

[0056] <3D printing method> The application unit 101, the light irradiation unit 202, and the stage driving unit form a shaped object 170 having a predetermined shape by the same operation as in the second embodiment. When the uncured ink layer 161 is formed, the unevenness forming roller 704A contacts the surface of the ink layer 161 while rotating in the direction indicated by the arrow Y2, and forms minute recesses 151C corresponding to the shape of the protrusions 704C on the surface. At this time, the rotation speed of the unevenness forming roller 704A is sufficiently faster than the movement speed of the stage 103. At this time, the unevenness forming roller 704A removes excess uncured ink from the parts of the surface of the unevenness forming roller 704A other than the protrusions 704C, and flattens the parts of the surface of the ink layer 161 other than the recesses 151C. The scraper 704B scrapes off the excess uncured ink removed by the unevenness forming roller 704A.

[0057] The light irradiation unit 202 irradiates the ink layer 161 in which the recesses 151C are formed with UV light L2. As a result, the ink layer 161 is formed with a semi-cured surface region 151 in which minute recesses 151C are formed on the surface and a completely cured internal region 152. After that, when a layer of uncured ink is formed on the semi-cured surface region 151 in which the recesses 151C are formed, the uncured ink penetrates into the recesses 151C of the surface region 151. Compared to when the entire surface of the surface region 151 is flat, the contact area between the surface including the recesses 151C of the surface region 151 and the uncured ink, that is, the interface, is larger. As a result, the number of functional groups that bond firmly at the interface can be increased, and the strength between the layers that constitute the shaped object 170 can be increased.

[0058] [Eighth embodiment] Next, an eighth embodiment of the present disclosure will be described. Fig. 9 is a side view of a three-dimensional printing device according to the eighth embodiment of the present disclosure. Note that the same components as those of the three-dimensional printing device 7 of the seventh embodiment are given the same reference numerals and the description thereof will be omitted.

[0059] <Configuration of 3D printing device> As shown in FIG. 9, the three-dimensional printing apparatus 8 includes a coating unit 101, a light irradiation unit 802, a stage 103, and a concave-convex forming unit 804.

[0060] The unevenness forming unit 804 has the same configuration as the unevenness forming unit 704, except that the unevenness forming roller 804A is provided instead of the unevenness forming roller 704A. The unevenness forming roller 804A is made of a material that can transmit UV light, such as a transparent material. A plurality of protrusions 704C are provided on the surface of the unevenness forming roller 804A. The unevenness forming roller 804A is formed in a cylindrical shape. A non-rotating cylindrical member 805D is inserted into the cylindrical interior of the unevenness forming roller 804A. The unevenness forming roller 804A is configured to rotate in the direction of the arrow Y2 by applying a rotational force from a rotational force applying unit (not shown). A slit 805E extending in a direction perpendicular to the paper surface of FIG. 9 is formed on the outer circumferential surface of the cylindrical member 805D. The scraper 704B is provided forward of the slit 805E in the rotational direction of the unevenness forming roller 804A.

[0061] The light irradiation unit 802 includes a plurality of light sources 202A similar to the light irradiation unit 202. The plurality of light sources 202A are arranged inside a cylindrical member 805D in a direction perpendicular to the plane of the paper in FIG. 9. The light sources 202A irradiate the outside of the cylindrical member 805D with UV light through a slit 805E. The UV light from the light sources 202A is transmitted through the unevenness forming roller 804A and irradiated onto the surface region 151.

[0062] <3D printing method> The application unit 101, the light irradiation unit 802, the irregularity forming unit 804, and the stage driving unit form a shaped object 170 of a predetermined shape by the same operation as in the seventh embodiment. When the uncured ink layer 161 is formed, the irregularity forming roller 804A forms minute recesses 151C on the surface of the ink layer 161 and flattens the portion other than the recesses 151C. At this time, the rotation speed of the irregularity forming roller 804A is sufficiently faster than the movement speed of the stage 103. The excess uncured ink removed by the irregularity forming roller 804A is scraped off by the scraper 704B. At this time, the portion of the irregularity forming roller 804A facing the slit 805E is always in a state where the ink has been removed. As a result, the UV light from the light source 202A is irradiated onto the surface region 151 without the light intensity of the UV light being reduced.

[0063] The light irradiation unit 802 irradiates UV light onto the ink layer 161 in which the recesses 151C have been formed. In this way, the surface region 151 can be semi-cured immediately after the unevenness forming roller 804A has flattened the surface and formed the recesses 151C, so that the shape of the recesses 151C can be accurately controlled. Furthermore, since the light irradiation unit 802 is disposed inside the unevenness forming roller 804A, the equipment can be made compact.

[0064] [Ninth embodiment] Next, a ninth embodiment of the present disclosure will be described. Fig. 10 is a side view showing a state after a modeling process of a modeled object according to the ninth embodiment of the present disclosure.

[0065] As shown in Fig. 10, a model 900 formed on a stage 103 is formed by a three-dimensional printing method and is composed of multiple ink layers deposited along a deposition direction Y3. The model 900 includes a first structure 901 formed with a first light-curable ink (first ink) and a second structure 902 formed with a second light-curable ink (second ink) of a different color from the first ink. The first structure 901 and the second structure 902 are alternately arranged and connected in the horizontal direction. In addition, both ends of the model 900 in the horizontal direction are composed of the second structure 902.

[0066] Here, the shape of a columnar object 903 formed with a small bottom area by the three-dimensional printing method according to the first to eighth embodiments tends to be a trapezoid in side view with the upper base shorter than the lower base. The reason is that the side of the object 903 has a low curing rate and is in a soft state, that is, the side is in a semi-cured state, so that the ink constituting the side is likely to drip. Even in the object 900 in which the first structural portion 901 and the second structural portion 902 are adjacent to each other, the semi-cured surface region of the first structural portion 901 and the semi-cured surface region of the second structural portion 902 come into contact with each other, so that the boundary between the first structural portion 901 and the second structural portion 902 becomes unclear. As a result, the completed object 900 has low shape precision.

[0067] Therefore, in the ninth embodiment, first, a single ink layer is formed by alternately ejecting a first ink and a second ink from an application section, and then, by performing this formation process multiple times, multiple ink layers are deposited.

[0068] When each ink layer is deposited, the light irradiation unit applies the 3D printing method according to any one of the first to eighth embodiments to the region made of the first ink, and irradiates UV light to semi-cure the surface region and completely cure the internal region. This increases the strength between the ink layers constituting the first structure 901, and can increase the strength of the entire model 900. The strength of the entire model 900 is determined by this first structure 901.

[0069] In addition, when each ink layer is deposited, the light irradiation unit irradiates the area made of the second ink with UV light that completely cures the entire area. As a method for completely curing the entire area made of the second ink in this way, a method of setting the light intensity of the UV light irradiated to the uncured ink layer to a light intensity that completely cures the entire ink layer, a method of temporarily lowering the oxygen concentration when irradiating the uncured ink layer with UV light, and a method of using an ink that is completely cured by UV light with a light intensity that semi-cures the first ink as the second ink and irradiating the second ink with the same UV light as the first ink are adopted. As a result, although the interlayer strength of the ink layers constituting the second structure portion 902 is weaker than that of the first structure portion 901, it is possible to form the second structure portion 902 that has higher shape accuracy than the first structure portion 901. In addition, the boundary between the first structure portion 901 and the second structure portion 902 becomes clear, and the shape accuracy of the entire model 900 can be improved.

[0070] The object formed by the method of the ninth embodiment may be composed of a plurality of structural parts each composed of three or more different types of ink, in which case a multi-colored object can be formed. Also, one of the second structural parts 902 may be formed of an ink that dissolves in water or a solvent, and after the completion of modeling, the second structural part 902 may be dissolved to separate the object 900 into two or more parts.

[0071] [Tenth embodiment] Next, a tenth embodiment of the present disclosure will be described. Fig. 11 is a side view of a shaped object according to the tenth embodiment of the present disclosure.

[0072] As shown in FIG. 11, the shaped object 1000 is formed by a three-dimensional printing method and is composed of a plurality of ink layers deposited along a deposition direction Y3. The shaped object 1000 includes an outer frame 1001, a connection portion 1002, and a product portion 1003. The outer frame 1001 is formed with a positioning hole 1001A. The connection portion 1002 connects the outer frame 1001 and the product portion 1003 so that the product portion 1003 is fixed inside the outer frame 1001. The outer frame 1001 and the product portion 1003 are structured such that the interlayer strength of the plurality of ink layers is high by the three-dimensional printing method according to any one of the first to ninth embodiments. On the other hand, the connection portion 1002 is structured such that the interlayer strength of the plurality of ink layers is weaker than that of the outer frame 1001 and the product portion 1003, and is structured such that the interlayer strength of the plurality of ink layers is low. That is, the shaped object 1000 is composed of parts with high strength (the outer frame 1001 and the product portion 1003) and parts with low strength (the connection portion 1002). Note that the method for forming the connection portion 1002 having the above-mentioned strength can be the method for forming the second structural portion 902 exemplified in the ninth embodiment.

[0073] This molded object 1000 is used as follows. For example, the molded object 1000 is fixed to a fixed structure (not shown) via a positioning jig (not shown) positioned in a positioning hole 1001A of the outer frame 1001. After the fixing is completed, an external force is applied to the connection portion 1002 to break it, and the product portion 1003 is removed from the outer frame 1001. The direction of the external force applied at this time is perpendicular to the stacking direction Y3. By applying an external force in such a direction to the connection portion 1002, the connection portion 1002 can be easily broken. If the direction of the external force applied to the connection portion 1002 is illustrated on the outer frame 1001, a worker can easily recognize the direction of the external force applied to the connection portion 1002. Such a method of use can be applied at a construction site, etc.

[0074] Product part 1003 may be composed of a part with high strength and a part with low strength. For example, a fracture origin may be intentionally created in product part 1003 as a part with low strength, thereby limiting the failure mode of product part 1003. In this way, when product part 1003 fails, it can be made to fail safely, that is, as intended in advance. [Industrial Applicability]

[0075] The 3D printing apparatus and 3D printing method according to the present disclosure are widely used when creating objects that require high strength. [Explanation of symbols]

[0076] 1,2,3,4,5,6,7,8 3D printing equipment 100 Printing room 101 Application section 101A Nozzle 102, 202, 602, 802 Light irradiation unit 102A,202A,602A light source 103 Stage 104 Temperature control unit 104A Temperature Sensor 150,303 Photocurable ink 151,171 surface area 151A First Surface Division Region 151B Second surface division area 151C Recess 152,172 internal area 153 Interface 160,161 Ink layer 170,900,903,1000 Modeled objects 305,507 Hardening treatment section 305A Metal Halide Lamp 405 Oxygen concentration control unit 405A Gas Supply Unit 405B Oxygen Concentration Meter 405C Mixed Gas Composition Determination Unit 405D mixer 405E Oxygen Generator 405F Nitrogen Generator 405G Gas Nozzle 503 Coating stage 504 Hardening stage 505 Stage Drive Unit 506 Transfer Section 506A Suction Pad 507A heating section 507B Entrance shutter 507C Exit shutter 508 Plate 602B First light source 602C Second Light Source 603 Irradiation control unit 704,804 Unevenness forming part 704A, 804A Concave and convex forming roller 704B Scraper 704C protrusion 805D Cylindrical member 805E Slit 901 First structural part 902 Second structural part 1001 Outer frame 1001A Positioning hole 1002 Connection 1003 Product Department A. Air G4 mixed gas L1 UV light L2 UV light L3 UV light

Claims

1. A three-dimensional printing apparatus for forming a model composed of multiple layers of photocurable ink, a coating section for depositing the plurality of layers; a light irradiation unit that irradiates light to semi-cure a surface region of each of the plurality of layers deposited and to completely cure an internal region other than the surface region; A three-dimensional printing apparatus comprising: an unevenness forming unit that forms unevenness on the surface of the layer before the light is irradiated.

2. The three-dimensional printing apparatus according to claim 1 , further comprising an oxygen concentration control unit that controls the oxygen concentration around the surface region.

3. The three-dimensional printing device according to claim 2 , wherein the oxygen concentration control unit controls the oxygen concentration around the surface region so that the surface region irradiated with the light is brought into a predetermined semi-cured state.

4. The three-dimensional printing device according to claim 2 or 3, wherein the oxygen concentration control unit controls the oxygen concentration around the surface region of the object so that the surface region of the object is in a completely cured state after formation of the object is completed.

5. The three-dimensional printing apparatus according to claim 1 , further comprising an after-hardening processing unit that completely hardens a surface region of the object after formation of the object is completed.

6. The three-dimensional printing apparatus according to claim 5 , wherein the post-hardening processing unit includes a heating unit that heats the model.

7. A three-dimensional printing device described in any one of claims 1 to 6, further comprising a temperature control unit that controls the temperature around the deposited layer so that the surface region irradiated with the light reaches a predetermined semi-cured state and the internal region reaches a predetermined fully cured state.

8. The three-dimensional printing device according to claim 1 , wherein the wavelength range of the light irradiated by the light irradiating unit is 150 nm or less.

9. The three-dimensional printing device according to claim 1 , wherein the light irradiation unit includes a plurality of light-emitting elements that output light of different wavelengths.

10. An irradiation control unit is further provided, The light irradiation unit includes a plurality of light sources. The three-dimensional printing device according to any one of claims 1 to 9, wherein the irradiation control unit divides the plurality of light sources into two or more groups and irradiates light of different light intensities for each of the two or more groups, thereby varying the semi-cured state of the areas in the surface region where the light of different light intensities is irradiated.

11. the irregularity forming unit is provided with an irregularity forming roller that is formed in a cylindrical shape from the light transmitting material and has protrusions arranged on a cylindrical surface for forming the irregularities, The three-dimensional printing device according to claim 1 , wherein the light irradiation unit is disposed inside the cylindrical unevenness forming roller.

12. A three-dimensional printing apparatus for forming a model composed of multiple layers of photocurable ink, a coating section for depositing the plurality of layers; a light irradiation unit that irradiates light each time the plurality of layers are deposited, so as to semi-cure a surface region of the deposited layer and completely cure an internal region other than the surface region; An irradiation control unit, The light irradiation unit includes a plurality of light sources. The irradiation control unit divides the multiple light sources into two or more groups, and irradiates light of different light intensities for each of the two or more groups, thereby varying the semi-cured states of the areas in the surface region where the light of different light intensities is irradiated, and forms first surface layer divided areas and second surface layer divided areas having different semi-cured states alternately along a direction perpendicular to the deposition direction of the multiple layers.

13. A three-dimensional printing apparatus for forming a model composed of multiple layers of photocurable ink, a coating section for depositing the plurality of layers; a light irradiation unit that irradiates light each time the plurality of layers are deposited to semi-cure a surface region of the deposited layer and to completely cure an internal region other than the surface region, The light irradiation unit irradiates a first region made of the first ink with light to semi-cure a surface region of the first region and completely cure an internal region of the first region other than the surface region, and irradiates a second region made of the second ink with light to completely cure the entire second region, each time a first ink and a second ink are alternately ejected in a horizontal direction to deposit the multiple layers.

14. A three-dimensional printing apparatus for forming a model composed of multiple layers of photocurable ink, a coating section for depositing the plurality of layers; a light irradiation unit that irradiates light each time the plurality of layers are deposited to semi-cure a surface region of the deposited layer and to completely cure an internal region other than the surface region, A three-dimensional printing device in which, when forming the outer frame of a molded object, a product portion inside the outer frame, and a connection portion connecting the outer frame and the product portion, each time one of the multiple layers is deposited, the light irradiation unit semi-hardens surface regions of the deposited layer corresponding to the outer frame and the product portion, and completely hardens internal regions other than the surface regions to form the outer frame and the product portion, and each time one of the multiple layers is deposited, the light irradiation unit completely hardens regions of the deposited layer corresponding to the connection portion, to form the connection portion.

15. A three-dimensional printing method for forming a model, comprising the steps of: depositing multiple layers of photocurable ink; a step of irradiating a surface region of each of the plurality of layers deposited with light so as to semi-cure the surface region of the deposited layer and completely cure an internal region other than the surface region; and forming projections and recesses on the surface of the layer before the light is irradiated.

16. the shaped object includes a first structure formed using a first light curable ink, and a second structure connected to the first structure and formed using a second light curable ink, the step of depositing one of the layers includes a step of ejecting the first light curable ink and the second light curable ink at different timings to form the one of the layers; 16. The three-dimensional printing method according to claim 15, wherein the light irradiating step includes a step of irradiating a region of the deposited layer made of the first light-curable ink with light that semi-cures a surface region of the region and completely cures an internal region other than the surface region, and a step of irradiating the deposited layer with light that completely cures an entire region of the deposited layer made of the second light-curable ink.

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