JP5621389B2 - Modeling method - Google Patents

Description

  The present invention relates to a modeling method for forming a modeled object by stacking layers composed of particles bound via a binding liquid.

  Conventionally, an additive manufacturing method is frequently used as a method (rapid prototyping) of a prototype quickly. In the additive manufacturing method, a model of a model is divided into a number of two-dimensional cross-sectional layers by three-dimensional CAD or the like. And the modeling object mentioned above is formed by laminating | stacking the layered structure corresponding to each two-dimensional cross-sectional layer in order.

  Specifically, for example, as described in Patent Document 1, first, particles including ceramic, metal, or the like are formed in layers. Next, a binding liquid that binds the particles is discharged to a part of the layer made of the particles. Then, the binding liquid that has penetrated into the voids between the particles binds the particles together with hardening thereof, thereby forming a binding region corresponding to the layered structure in the layer. Thereafter, similarly, the formation of the layer composed of the particles and the discharge of the binding liquid are alternately repeated to form a laminate composed of a plurality of the layers. And the unbound area | region other than a binding area | region is removed from a laminated body, and the molded article in which the some binding area | region was laminated | stacked is formed.

Japanese Patent No. 2729110

  By the way, in the modeling method described above, when the upper-layer binding region is formed, the lower-layer binding region, which is the base, is surrounded by the lower-layer non-binding region. Therefore, if the upper layer binding region is formed so as to connect the lower layer binding region and the lower layer unbonded region, the upper layer binding region protrudes from the lower layer binding region. A body can also be formed. On the other hand, in the shaped object in which the upper binding region projects from the lower binding region, a corner portion including the lower surface of the upper layer and the end surface of the lower layer is formed. When an external force acts on the upper layer binding region, stress associated with the external force is concentrated at the corners described above.

  In particular, when removing the unbound region by flowing a liquid through the above-described laminate, the pressure of the liquid directly acts on the overhanging bound region, so that the associated stress is concentrated on the corners. Therefore, the above-described modeling method is strongly required to increase the mechanical strength in the vicinity of the corner portion against the force acting on the upper layer.

  The present invention has been made in view of these conventional situations, and an object of the present invention is to provide a modeling method capable of increasing the mechanical strength against the force acting on the projecting portion of the modeled object. is there.

The present invention provides a layer forming step for forming a layer containing particles, and a layered structure in which the particles are bonded by curing the binding solution after infiltrating a part of the layer with the binding solution. Including a binding step of forming a structure in the layer and a removal step of removing a portion other than the layered structure from the layer including the layered structure, wherein the layer forming step and the binding step are alternately performed. By repeatedly performing the removal step after forming a laminate composed of the layers including the layered structure,
A modeling method in which a modeled object in the form of a layered structure is formed, wherein the (k + 1) th layer (k is an integer of 1 or more) is designated as the kth layer. In the case where the k-th layer is formed so as to protrude from above to the unbound region of the k-th layer, in the binding step of the (k + 1) -th layer, the k-th layer-bound region and the k-th layer The amount of the binding liquid applied is made larger than that of the second region other than the first region with respect to the first region including immediately above the boundary with the unbound region.

  According to the present invention, when the upper layer binding region is formed so as to extend from the lower layer binding region to the lower layer unbonded region, at the boundary between the lower layer binding region and the unbound region, The upper layer binding liquid will ooze out. As a result, the upper layer binding liquid penetrates to the boundary between the binding region and the non-binding region in the lower layer. As a result, after the upper binding liquid is cured, the exuded binding liquid binds the particles to each other at the corners formed by the lower surface of the binding area in the upper layer and the end face of the binding area in the lower layer. Come to wear. Therefore, the stress at the corners is dispersed in the vicinity of the boundary by the amount of the binding liquid that oozes out to bind the particles near the boundary. Further, since the stress is dispersed by increasing the coating amount of the binding liquid, the density of the binding liquid does not decrease in the upper layer, and the mechanical strength of the upper layer does not decrease. Therefore, the mechanical strength of the molded article can be increased.

  In the present invention, in the binding step of the first region of the (k + 1) th layer, on the unbound region of the kth layer, the application position of the binding liquid is close to just above the boundary. Accordingly, it is preferable to increase the amount of the binding liquid applied.

  According to this modeling method, the amount of the binding liquid that oozes out from the upper layer to the lower layer becomes larger as the amount becomes closer to just above the boundary of the lower layer. For this reason, in the corner portion composed of the lower surface of the binding region in the upper layer and the end surface of the binding region in the lower layer, the thickness of the upper layer constituting the corner portion increases as the boundary in the lower layer becomes closer. The lower-layer binding region and the upper-layer binding region are connected to each other through a tapered portion that expands toward the lower-layer binding region. Therefore, as the angle formed between the lower surface of the binding region in the upper layer and the end surface of the binding region in the lower layer becomes smaller, the stress concentration at the corners is further relaxed, and the mechanical strength in the molded article can be further increased. it can.

  In the present invention, in the binding step of the (k + 1) th layer, the coating amount per unit area on the surface of the (k + 1) th layer is binarized, and the first region includes a first Preferably, the binding liquid is applied in an application amount, and the binding liquid is applied to the second region in a second application amount that is smaller than the first application amount.

According to this invention, the above effect can be obtained by a simple application control mode in which the application amount of the binding liquid is switched between the first application amount and the second application amount.
In the present invention, in the binding step of the (k + 1) th layer, a discharge head that discharges the binding liquid as droplets is used, and the discharge head is scanned with respect to the (k + 1) th layer. The plurality of droplets are ejected from the ejection head to the (k + 1) th layer with the same size, and in the first region, the ejection interval in one scan is shorter than that in the second region. It is preferable to do.

  According to the present invention, the binding liquid is partially increased while the ejection head is scanned only once with respect to the upper binding area. Thereby, a molded article can be efficiently formed without increasing the number of scans of the ejection head.

  The present invention forms a layer containing the particles from a slurry containing hydrophobic particles, an aqueous solvent, and an amphiphilic solid polymer dissolved in the aqueous solvent. In the removing step, an aqueous liquid is formed. It is preferable to remove a part other than the layered structure from the layer including the layered structure by flowing a layer.

  According to this invention, as a material for forming the layer, a slurry in which hydrophobic particles are suspended in an aqueous solvent is used. For this reason, even if vibration is given to the slurry during formation of the modeled object, the hydrophobic particles are held in the aqueous solvent, so that scattering of the particles is suppressed. In addition, since the aqueous solvent is used as a solvent for suppressing the scattering of the particles, the particles are dissolved in the solvent, or the particles are swollen by absorbing the solvent. The body can be prevented from being denatured. Furthermore, an amphiphilic solid polymer is added as a constituent material of the slurry. Such an amphiphilic solid polymer has affinity with the hydrophobic particles at the hydrophobic site and has affinity with the aqueous solvent at the hydrophilic site. Therefore, the hydrophobic particles can be uniformly dispersed in the aqueous solvent through the amphiphilic solid polymer. Therefore, in a model formed using such modeling slurry, hydrophobic particles that are the forming material are uniformly present.

  And in the said modeling method, the unbound area | region is removed from a laminated body with an aqueous liquid. At this time, since the slurry constituting the layer includes an aqueous solvent and an amphiphilic solid polymer, the unbound region can be easily removed with an aqueous liquid.

The flowchart which shows the procedure of the modeling method in 1st and 2nd embodiment of this invention. (A) (b) (c) Sectional drawing which shows the cross-sectional structure of the layer in each process of a modeling method along a procedure. (A) (b) (c) Sectional drawing which shows the cross-sectional structure of the layer in each process of a modeling method along a procedure. (A) The figure which shows the discharge position of the upper layer in 1st embodiment corresponding to the cross-section of an upper layer, (b) The graph which shows the discharge amount for every discharge position of the upper layer in 1st embodiment. The figure which shows the cross-section of the binding area | region contained in the upper layer in 1st embodiment with the enlarged view of a corner | angular part. (A) The figure which shows the discharge position of the upper layer in 2nd embodiment corresponding to the cross-section of an upper layer, (b) The graph which shows the discharge amount for every discharge position of the upper layer in 2nd embodiment. The figure which shows the cross-section of the binding area | region contained in the upper layer in 2nd embodiment with the enlarged view of a corner | angular part. (A) The figure which shows the discharge position of the upper layer in a modification corresponding to the cross-sectional structure of an upper layer, (b) The graph which shows the discharge amount for every discharge position of the upper layer in a modification.

(First embodiment)
Hereinafter, 1st embodiment in the modeling method of this invention is described with reference to FIGS. First, the composition of the molding slurry used in the modeling method will be described. The slurry for modeling used in the present embodiment is a suspension in which three materials, a hydrophobic particle, an aqueous solvent, and an amphiphilic solid polymer are kneaded.

  The hydrophobic particles are a main constituent material of a modeled object formed using a modeling slurry. As the hydrophobic particles, hydrophobic resin particles such as acrylic resin powder, silicone resin powder, acrylic silicone resin powder, polyethylene resin powder, and polyethylene acrylic acid copolymer resin powder can be used. In addition, the hydrophobic particle | grains in this embodiment are the particle | grains which do not melt | dissolve 1g or more with respect to 100g of aqueous solvents.

  With respect to the aqueous solvent, the solubility of the hydrophobic particles constituting the modeled object is low as described above. Therefore, it is difficult for the hydrophobic particles to be modified due to dissolution in the solvent or absorption of the solvent. Therefore, it is preferable as a medium for suppressing scattering of hydrophobic particles. The aqueous solvent includes water and a non-organic solvent such as an aqueous solution of an inorganic salt. Of these, water is preferably used as the aqueous solvent. Further, the aqueous solvent may be one obtained by adding a water-soluble organic solvent to water.

  The amphiphilic solid polymer is a material that forms a shaped object together with the hydrophobic particles. Since this solid polymer is amphiphilic, it dissolves in the aqueous solvent due to the affinity with the aqueous solvent due to the hydrophilic portion, and the hydrophobic particles due to the affinity with the hydrophobic particles due to the hydrophobic portion. Disperses the body in a solvent. As the amphiphilic solid polymer, a material having a hydrocarbon chain as a main chain and a hydrophilic functional group as a side chain can be used. Among them, it is preferable to use polyvinyl alcohol which has a straight hydrocarbon chain but has higher hydrophilicity than other materials.

  In the slurry in which the above three materials are kneaded, the hydrophobic particles of the amphiphilic solid polymer are also in a state where the hydrophobic particles are cross-linked with each other. Therefore, even when vibrations are applied to the slurry during formation of the shaped object, the hydrophobic particles are retained in the structure formed by cross-linking between the particles, so that the scattering of the particles is suppressed. Will come to be.

  In addition, the hydrophobic particles are uniformly dispersed in the aqueous solvent through the hydrophilic portion of the amphiphilic solid polymer that interacts in the hydrophobic portion. Therefore, in the molded object formed using such a slurry, the hydrophobic particles as the forming material are present uniformly. In addition, since these amphiphilic solid polymers are themselves a material for forming a shaped object, it is necessary to remove the amphiphilic solid polymer during or after the formation of the shaped object. And not.

Next, a modeling method using the slurry having the above composition will be described. First, the flow of each process included in the modeling method will be described with reference to FIGS.
In the modeling method, first, in the sacrificial layer forming step (step S11: FIG. 2A), the slurry is applied on the substrate 11 such as a glass substrate or a plastic sheet so as to have a thickness of 200 μm, for example. Is done. As a result, the sacrificial layer 12 is formed as the lowermost layer of the slurry layer. For applying the slurry, a known method such as a squeegee method, a screen printing method, a doctor blade method, and a spin coating method can form a slurry layer having a substantially uniform thickness on the substrate 11. Can be used.

  Next, in the slurry layer forming step (step S12: FIG. 2B), the slurry is applied so as to have a thickness of 100 μm, thereby forming the slurry layer 21a. It should be noted that the above-described known method can be used when forming the slurry layer 21a as well as when the sacrificial layer 12 is formed.

  Then, in the discharging step (step S13: FIG. 2C), ultraviolet rays serving as a binding liquid are formed on the slurry layer 21a in the portion that becomes the binding region 22a that is a part of the molded article 20 (FIG. 3). UV ink I containing a curable resin is ejected. At this time, an ejection head 31 that ejects UV ink I as droplets is used, and the UV ink I is scanned from the ejection head 31 toward the slurry layer 21a while the ejection head 31 is scanned in one direction with respect to the slurry layer 21a. I droplets are ejected.

Here, in the slurry layer 21a, a hydrophobic particle cross-linked structure is formed by the amphiphilic solid polymer, so that the hydrophobic particles are arranged with a predetermined space between each other. The space is filled with an aqueous solvent. Therefore, the UV ink I discharged from above the slurry layer 21a toward the surface of the slurry layer 21a penetrates isotropically from the surface of the slurry layer 21a through the above-described space. Incidentally, since the hydrophobic region in the amphiphilic solid polymer in the slurry layer 21a has affinity for the UV ink I, the UV ink I can easily penetrate into the slurry layer 21a.

  The UV ink I includes a cationic polymerization type ultraviolet curable resin that cures by a polymerization reaction using a cation as an active species, and a radical polymerization type ultraviolet curable resin that cures by a polymerization reaction using a radical as an active species. There is something to include. In the present embodiment, any of these UV inks I can be used. However, the UV ink I is ejected to a portion that becomes the binding region 22a, and is then cured together with the hydrophobic particles included in the binding region 22a. Therefore, it is preferable to select compatible materials for the UV ink I, particularly the ultraviolet curable resin and the hydrophobic particles. That is, it is preferable to use the same material for the UV ink I and the hydrophobic particles, for example, the acrylic UV ink I and the acrylic resin powder. Alternatively, it is preferable to use UV ink I and hydrophobic particles having a material similar to UV ink I introduced on the surface, for example, acrylic UV ink I and acrylic silicone resin powder. Here, the same system means that the main skeleton of the repeating unit structure constituting the hydrophobic particles and the main skeleton of the unit structure of the resin contained in the UV ink I are the same. In addition, the same system is different in the side chain functional group in the unit structure and part of the main skeleton in the unit structure, but the interaction between the hydrophobic liquid and the resin is substantially the same as the interaction between the hydrophobic particles. This means that the main skeletons of the unit structure partially overlap each other. Therefore, when each of the hydrophobic particles and the resin is a copolymer, those in which the composition ratios of the atoms contained in these particles are not the same are assumed to be the same system.

  Subsequently, in the ultraviolet irradiation step (step S14: FIG. 3A), the entire slurry layer 21a is irradiated with ultraviolet L, whereby the particles contained in the binding region 22a are passed through the UV ink I. Bonded and cured. The binding process is constituted by the above-described ejection process and ultraviolet irradiation process. Further, the ultraviolet ray L used in the ultraviolet ray irradiation step does not have to be applied to the entire slurry layer 21a, and may be applied to at least a portion that becomes the binding region 22a. In addition, the irradiation of the ultraviolet light L is performed alternately with the discharge of the UV ink I onto the portion to be the binding region 22a by, for example, an ultraviolet irradiation device mounted on the discharge head 31, or separately from the discharge head 31. It can be performed for each slurry layer by the ultraviolet irradiation device provided, or can be performed for a plurality of slurry layers at once.

  By the discharge of the UV ink I and the irradiation with the ultraviolet ray L as described above, a binding region 22a that is a layered structure in which particles are bound to each other is formed, and a part of the modeled product 20 is the binding region 22a. Formed by. On the other hand, in the slurry layer 21a, an unbound region 23a made only of the molding slurry is formed in a portion other than the portion that becomes the bound region 22a. Therefore, as shown in FIG. 3B, when the upper binding region 22b extends from the lower binding region 22a, the lower side of the protruding portion is supported by the lower unbonded region 23a. . Therefore, although a corner portion composed of the end surface of the binding region 22a in the lower layer and the lower surface of the binding region 22b in the upper layer is formed, the same angle as long as the lower unbound region 23a is filled in the corner portion. It can suppress that stress concentrates on a part.

The three steps from the slurry layer forming step (step S12) to the ultraviolet ray irradiating step (step S14) are repeatedly performed in order until all of the binding regions constituting the shaped article 20 are formed. For example, as shown in FIG. 3B, when the modeled object 20 is composed of five slurry layers 21a, 21b, 21c, 21d, and 21e, the above three steps are repeated five times in order. Thus, since the laminated body comprised from a several layer can be formed by repeating three processes from a layer formation process to an ultraviolet irradiation process in order, the shape of the molded article 20 formed by the said modeling method The degree of freedom related to increases.

  When all of the binding regions 22a, 22b, 22c, 22d, and 22e constituting the shaped article 20 are formed, in the unbound region removing step (step S15: FIG. 3C), the slurry layers 21a, 21b, The unbound regions 23a, 23c, 23d, and 23e are removed from the stacked body of 21c, 21d, and 21e. The unbound regions 23a, 23c, 23d, and 23e can be removed by immersing the laminate together with the substrate 11 in an aqueous liquid, for example, in water, or flowing water through the laminate at a predetermined pressure. . Then, each of the binding regions 22a, 22b, 22c, 22d, and 22e is laminated by performing the sacrificial layer forming step, the slurry layer forming step, the discharging step, the ultraviolet irradiation step, and the unbound region removing step. A shaped object is formed.

  Next, in the case where the upper binding region is formed so as to protrude from the lower binding region, the upper layer ejection step will be described in detail. 4A and 4B are diagrams in which the discharge position of the UV ink I in the upper layer is associated with the discharge amount per unit area on the surface of the upper layer, and is performed after the step of FIG. It is a figure shown about the discharge process. In FIG. 4A, the discharging process is performed so that all of the illustrated slurry layer 21b becomes a binding region.

  As shown in FIG. 4, when the upper layer binding region is formed so as to connect the lower layer binding region and the lower layer unbonded region, the discharge amount of the UV ink I to the upper layer is The difference in whether or not the lower side of the UV ink I ejection position is near the boundary between the bound area and the unbound area in the lower layer is greatly different.

  Specifically, as shown in FIG. 4, when the discharge position of the UV ink I is sufficiently far from the position immediately above the boundary between the unbound region 23a and the bound region 22a, the UV ink I per unit area. Is maintained at the reference amount Q1. On the other hand, when the discharge position of the UV ink I is close to immediately above the lower binding area 22a, the discharge amount of the UV ink I per unit area is both on the unbound area 23a and on the binding area 22a. It is increased from the reference amount Q1. At this time, on the lower unbound region 23a, the discharge amount of the UV ink I per unit area increases as the discharge position of the UV ink I approaches the lower bound region 22a. When the discharge position of the UV ink I is immediately above the boundary between the unbound region 23a and the bound region 22a, the increase with respect to the reference amount Q1 reaches the oozing amount Q2.

  The reference amount Q1 is a discharge amount in which the UV ink I diffuses over the entire upper layer in the thickness direction and the UV ink I does not ooze out to the lower layer. Further, the amount of exudation Q2 is the amount of the UV ink I discharged to the upper layer that exudes from the upper layer to the lower layer, and the amount of the UV ink I that exudes to the lower layer does not reach the lower surface of the lower layer It is. The reference amount Q1 and the exudation amount Q2 are appropriately changed depending on the composition of the UV ink I, the composition of the slurry constituting the upper layer and the lower layer, and the thickness of the upper layer.

  Next, the structure of the binding region formed by the UV ink I ejected with the above-described ejection amount will be described in detail with reference to FIG. FIG. 5 is an enlarged partial cross-sectional view showing a part of the cross-sectional structure of the binding region 22b in the upper layer.

As described above, in the region where the UV ink I is ejected more than the reference amount Q1 (high ejection region S), the UV ink I that has permeated into the upper layer is not separated from the lower binding region 22a and the lower binding region 22a. It oozes out to the boundary with the binding region 23a and the lower unbonded region 23a. At this time, the UV ink I that has oozed out into the lower binding region 22a does not penetrate into the lower binding region 22a, but penetrates into the boundary between the lower binding region 22a and the unbound region 23a. Since the lower binding region 22a contains a cured product of the UV ink I, the UV ink I permeates along the end surface of the binding region 22a having higher affinity. On the other hand, the UV ink I that has oozed into the lower unbound region 23a penetrates isotropically from the lower layer surface into the unbound region 23a. Further, the region where the UV ink I penetrates becomes larger as the discharge amount is lower.

  As a result, as shown in FIG. 5, a support auxiliary portion 24b is formed at a corner portion formed by the lower surface of the upper binding region 22b and the end surface of the lower binding region 22a. The amount of the UV ink I that oozes out from the binding region 22b into the non-binding region 23a increases as it approaches the lower binding region 22a. Therefore, the thickness of the support auxiliary portion 24b described above is increased in the binding region 22a. The closer you get, the bigger it will be. Then, the lower binding region 22a and the upper binding region 22b are connected via a tapered support auxiliary portion 24b that expands toward the lower binding region 22a.

  Therefore, as the angle formed between the lower surface of the upper binding region 22b and the end surface of the lower binding region 22a is reduced, the stress concentration at the corners is alleviated, and the mechanical strength of the molded article, particularly the lower layer The mechanical strength at the corner portion constituted by the binding region 22a and the upper binding region 22b can be increased. Further, since the stress is dispersed by increasing the amount of the UV ink I, the strength is not reduced due to the decrease in the density of the UV ink I in the upper layer. As a result, the mechanical strength of the modeled object can be increased, and as a result, the modeled object collapses even when the liquid is poured into the modeled object to remove the unbound region, and even during the process of forming the modeled object and after completion. It becomes possible to reduce a possibility of doing.

  Further, such a partial increase in the UV ink I can be realized in the following discharge control mode. For example, if the number of droplets of the UV ink I is assumed to be equal per unit area, the droplets in the region including just above the boundary between the bound region 22a and the unbound region 23a, that is, in the high ejection region S described above. Is made larger than other areas. Alternatively, if the volume of the droplets of the UV ink I is assumed to be the same in the entire upper layer, the number of droplets in the high ejection area S is made larger than in other areas. In the present embodiment, the discharge interval of the UV ink I in the high discharge region S is made shorter than that in other regions, thereby increasing the number of droplets in the high discharge region S. According to such a configuration, the above-described partial increase in the UV ink I can be realized by causing the ejection head 31 to scan the upper layer only once.

  The range of the high discharge region S depends on the length of the upper layer portion protruding from the lower binding region 22a, the length of the portion supporting the upper layer in the lower binding region 22a, the thickness of the upper layer, etc. They are different from each other. For example, when the length of the upper layer portion protruding from the lower binding region 22a is increased, a greater stress is concentrated on the corner portion due to the external force acting on the upper layer portion. Similarly, when the length of the lower binding region 22a is reduced, a larger stress is concentrated on the corner. Moreover, the mechanical strength of the upper layer decreases as the thickness of the upper layer decreases. Therefore, the length of the upper layer portion that protrudes from the lower binding region 22a, the length of the lower binding region 22a, and the thickness of the upper layer, and the thickness of the upper layer, also in one molded article, It is preferable to appropriately change the range, that is, the size of the support auxiliary portion 24b.

Incidentally, when forming a shaped object under the following conditions, in order to balance the relaxation of stress at the corner and the maintenance of the shape accuracy of the shaped object, the amount of exudation Q2 relative to the reference amount Q1 of UV ink I The ratio is preferably 5% to 25%, and more preferably 15% to 20%. Further, the distance d1 of the section (high discharge area S) in which the discharge amount of the UV ink I is larger than the reference amount Q1 is preferably not more than three times the thickness of the slurry layer, and the thickness of the slurry layer is 100 μm. The distance d1 is desirably 300 μm or less.
(A) Hydrophobic particles Charine R-170S (particle size 30 μm) (manufactured by Nissin Chemical Industry Co., Ltd.) (Charine: registered trademark)
-(B) Aqueous solvent water-(C) Amphiphilic solid polymer POVAL JP-03 (manufactured by Nippon Vinegar-Poval Co., Ltd.)
Composition ratio (A) :( B) :( C) = 7: 3.1: 0.22 (unit: g)
・ Thickness of each slurry layer 100μm
-UV ink Acrylic UV ink As explained above, according to the modeling method in this embodiment, the effect enumerated below can be acquired.

  (1) The UV ink I penetrating into the upper slurry layer 21b oozes out to the boundary between the bound region 22a and the unbound region 23a in the lower layer. Therefore, the upper layer UV ink I penetrates to the unbound region 23a around the boundary between the bound region 22a and the unbound region 23a in the lower layer. As a result, after the upper layer UV ink I is cured, the above-exuded UV ink I is separated from each other at the corners formed by the lower surface of the binding region 22b in the upper layer and the end surface of the binding region 22a in the lower layer. Will come to bind. For this reason, the stress at the corners is dispersed by the amount of the UV ink I that has exuded that binds the particles. Further, since the stress is dispersed by increasing the amount of the UV ink I, the strength is not reduced due to the decrease in the density of the UV ink I in the upper layer. Therefore, the mechanical strength of the molded article can be improved.

  (2) The amount of the UV ink I that oozes out from the upper layer to the lower layer increases as it approaches the lower binding region 22a. Therefore, at the corner portion formed by the lower surface of the binding region 22b in the upper layer and the end surface of the binding region 22a in the lower layer, the thickness of the upper layer constituting the corner portion increases as the thickness becomes closer to the lower binding region 22a. Then, the lower binding region 22a and the upper binding region 22b are bound via the tapered support auxiliary portion 24b that increases toward the lower binding region 22a. Therefore, as the angle formed between the lower surface of the binding region 22b in the upper layer and the end surface of the binding region 22a in the lower layer becomes smaller, the stress concentration at the corners is further relaxed, and the mechanical strength of the molded article is further increased. Can do.

  (3) On the lower binding region 22a, the increase from the reference amount Q1 is changed from the exudation amount Q2 to “0”, and the increase from the reference amount Q1 is changed from “0” to the exudation amount Q2. It was decided. The UV ink I that has penetrated into the upper layer easily oozes into the lower unbound region 23a and hardly oozes into the lower bound region 22a. Therefore, even if the discharge amount is increased on the lower binding region 22a, it is difficult to obtain the above-described effect sufficiently compared to the case where the same discharge amount is discharged onto the lower unbonded region 23a. In this regard, according to this modeling method, the UV ink I having a relatively small reference amount Q1 is ejected in a region where the UV ink I is unlikely to bleed into the lower layer, that is, a region where it is difficult to contribute to the stress dispersion at the corners. Is done. Therefore, waste of the UV ink I on the lower binding region 22a and imbalance of the density of the UV ink I on the upper layer can be suppressed. This is particularly effective when the range of the lower binding region 22a is large.

  (4) When applying the UV ink I, the ejection head 31 that ejects the UV ink I as droplets is used, and the binding region is formed by ejecting the droplets from the ejection head 31. Then, the UV ink I is partially increased by appropriately setting the discharge interval in the upper layer, and the discharge head is scanned only once immediately above the boundary between the bound region 22a and the unbound region 23a in the lower layer. It was. Thereby, it is possible to efficiently form a modeled object without increasing the number of scans of the ejection head 31.

  (5) A slurry was formed from water as an aqueous solvent, resin particles as hydrophobic particles, and polyvinyl alcohol as an amphiphilic solid polymer. Thereby, the resin particles are not in an independent state, but are in a state of being crosslinked with each other through the intervention of polyvinyl alcohol. Therefore, even when vibration or the like is given to the slurry during formation of the shaped article 20, since the resin particles are held in the structure formed by cross-linking between the particles, the scattering of the particles is suppressed. Become so.

(Second embodiment)
Hereinafter, the second embodiment of the modeling method of the present invention will be described mainly with respect to differences from the first embodiment with reference to FIGS. The second embodiment is different from the first embodiment in the discharge amount for each discharge position in the discharge step described above and the shape of the support assisting portion 24b obtained thereby. Therefore, in the following, this difference will be described in detail.

  6A and 6B are diagrams corresponding to FIG. 4 described in the first embodiment, and the discharge position of the UV ink I in the upper layer and the discharge amount per unit area on the surface of the upper layer. FIG. FIG. 7 is a diagram corresponding to FIG. 5 and shows a cross-sectional shape of the binding region formed when the UV ink I is ejected as shown in FIG.

  Also in the modeling method according to the second embodiment, when the upper binding region is formed so as to connect the lower binding region to the lower unbonded region, the UV ink I is discharged to the upper layer. The amount varies greatly depending on whether or not the lower side of the UV ink I ejection position is in the vicinity of the boundary between the bound region and the unbound region in the lower layer.

  Specifically, as shown in FIG. 6, when the binding region 22b is formed in the upper layer, the discharge amount of the UV ink I per unit area on the surface of the upper layer is set to two different values. In a region immediately above the boundary between the unbound region 23a and the bound region 22a and including the unbound region 23a and the bound region 22a (high discharge region S), the reference amount Q1 The UV ink I is ejected with an ejection amount that is larger than the exudation amount Q2. In areas other than the high discharge area S, the discharge amount of the UV ink I is maintained at the reference amount Q1.

  Even when UV ink I is ejected in this way, below the region where the UV ink I is ejected more than the reference amount Q1 in the upper layer, the lower bound region 22a, the boundary between the unbound region 23a and the bound region 22a, And the UV ink I oozes out to the lower unbound region 23a. At this time, the UV ink I that has oozed out into the lower binding region 22a does not penetrate into the lower binding region 22a, but penetrates into the boundary between the lower binding region 22a and the unbound region 23a. Since the lower binding region 22a contains a cured product of the UV ink I, the UV ink I permeates along the end surface of the binding region 22a having higher affinity. On the other hand, the UV ink I that has oozed out into the lower unbound region 23a penetrates approximately isotropically from the lower layer surface into the unbound region 23a. Therefore, even in the method of ejecting the same amount of UV ink I onto the unbound region 23a and the bound region 22a, the boundary between the bound region 22a and the unbound region 23a in the lower layer A relatively large amount of the UV ink I starts to ooze out.

  As a result, as shown in FIG. 7, the thickness of the auxiliary support portion 24b formed at the corner increases as it approaches the boundary between the unbound region 23a and the bound region 22a. Then, the lower binding region 22a and the upper binding region 22b are connected to each other via a tapered support auxiliary portion 24b that expands toward the lower binding region 22a. Note that the UV ink I that oozes out from the boundary between the unbound region 23a and the bound region 22a penetrates substantially isotropically from the lower surface to the unbound region 23a. Therefore, the end of the support auxiliary portion 24b opposite to the corner portion is formed in a hemispherical shape or a semicylindrical surface shape that protrudes toward the lower unbonded region 23a.

  As a result, the concentration of stress at the corners is alleviated and the mechanical strength of the molded article is increased. In addition, since the stress is dispersed by increasing the amount of the UV ink I, it is possible to prevent a decrease in strength due to a decrease in the density of the UV ink I in the upper layer, as in the first embodiment. It is the same.

Incidentally, when forming a modeled object under the following conditions, in order to balance the relaxation of the stress at the corner and the maintenance of the shape accuracy of the modeled object, the amount of exudation Q2 with respect to the reference amount Q1 of the UV ink I The ratio is preferably 5% to 25%, and more preferably 15% to 20%. Further, the distance d2 of the section (high discharge area S) in which the discharge amount of the UV ink I is larger than the reference amount Q1 is preferably not more than twice the thickness of the slurry layer, and the thickness of the slurry layer is 100 μm. The distance d2 is desirably 200 μm or less.
(A) Hydrophobic particles Charine R-170S (particle size 30 μm) (manufactured by Nissin Chemical Industry Co., Ltd.) (Charine: registered trademark)
-(B) aqueous solvent water-(C) amphiphilic solid polymer POVAL JP-03 (manufactured by Nippon Vinegar-Poval Co., Ltd.)-Composition ratio (A): (B): (C) = 7: 3. 1: 0.22 (unit: g)
・ Thickness of each slurry layer 100μm
UV ink Acrylic UV ink As described above, according to the modeling method in the second embodiment, in addition to the effects (1) and (3) to (5) described above, the following effects can be obtained. Can do.

  (6) The partial increase of the UV ink I with respect to the upper binding region is performed by switching between the reference amount Q1 and the discharge amount obtained by adding the exudation amount Q2 to the reference amount Q1. Thereby, the above-described effect can be obtained with a simple setting of switching between two ejection amounts.

In addition, the said embodiment can also be changed and implemented suitably as follows.
The above modeling method is not limited to the case of using the above modeling slurry, and it is repeated to form a layer composed of particles, apply UV ink I to the layer, and bind the particles together If it is with respect to the modeling method which forms a modeling object by, it can employ | adopt. In addition, when the layer comprised only from a granule is formed, in a removal process, it is possible to remove an unbound area | region by spraying air on a laminated body, for example.

  The UV ink I was discharged by the discharge head 31 onto the slurry layers 21a, 21b, 21c, 21d, and 21e. The method is not limited to this, and any method that can apply the UV ink I to the slurry layers 21a, 21b, 21c, 21d, and 21e can be used as appropriate.

  The coating amount of UV ink I may be changed as shown in FIG. That is, in the upper layer, the coating amount of the UV ink I is gradually increased from the reference amount Q1 as it approaches the binding region 22a from the lower unbonded region 23a. Then, the increase amount of the UV ink I reaches the amount Q2 before the border between the unbound region 23a and the bound region 22a, and the region immediately above the boundary and the binding adjacent to the boundary. In the region on the region 22a, the increase amount is kept at the exudation amount Q2. According to such an application control mode, an effect equivalent to or equivalent to the above effect can be obtained.

  -On the unbound area 23a in the first embodiment, the discharge amount of the UV ink I is proportional to the distance between the application position and the portion immediately above the boundary between the unbound area 23a and the bound area 22a. Although it is made smaller, it may be made exponentially smaller with respect to the distance. In short, any method may be used as long as the application amount of UV ink I per unit area at the application position is continuously increased as the application position of UV ink I approaches directly above the boundary.

  In the second embodiment, the application amount of the UV ink I per unit area is binarized on the unbound region 23a, but three or more different values may be set. In short, any method may be used as long as the application position of the UV ink I is close to just above the boundary, and the application amount of the UV ink I per unit area at the application position increases discontinuously.

  -On the unbound region 23a in the first embodiment, the coating amount of the UV ink I is proportional to the distance between the position immediately above the boundary between the unbound region 23a and the bound region 22a and the coating position. I tried to make it smaller. In addition, also on the binding region 22a, the application amount of the UV ink I may be reduced in proportion to the distance between the portion immediately above the boundary and the application position.

  On the binding region 22a in the above embodiment, the increase from the reference amount Q1 is changed from the exudation amount Q2 to “0”, and the increase from the reference amount Q1 is changed from “0” to the exudation amount Q2. It was decided. Not limited to this, the increase from the reference amount Q1 may be gradually changed or maintained from the reference amount Q1 also on the lower binding region 22a. In short, the UV ink I that has penetrated into the upper layer oozes out to the boundary between the bound region 22a and the unbound region 23a in the lower layer, so that the upper layer is applied to a region (high discharge region S) including the region immediately above the boundary. What is necessary is just to make the quantity of the UV ink I to be made larger than other areas.

  The binding liquid in the above embodiment is not limited to a liquid containing an ultraviolet curable resin, but may be embodied in a liquid containing a thermosetting resin or a liquid containing an ultraviolet curable resin and a thermosetting resin. it can.

  The sacrificial layer 12 is formed on the substrate 11 prior to the formation of the slurry layers 21a, 21b, 21c, 21d, and 21e constituting the modeled object 20, but the sacrificial layer 12 may not be formed. .

  -Modeled object 20 illustrated what was formed by five layers of slurry layers 21a, 21b, 21c, 21d, and 21e. Not only this but the number of the layers which comprise the molded article 20 can be made into two or more arbitrary numbers. Moreover, the shape of the structure formed in each slurry layer is also arbitrary.

  In the above embodiment, the region including the region immediately above the boundary may be a region having the region immediately above the boundary, or may be configured only directly above the boundary.

  d1, d2 ... distance, L ... ultraviolet light, I ... UV ink, Q1 ... reference amount, Q2 ... seepage amount, 20 ... shaped object, 21a, 21b, 21c, 21d, 21e ... slurry layer, 22a, 22b, 22c, 22d, 22e... Binding area, 23a, 23c, 23d, 23e... Unbonded area, 24b.

Claims (5)

A layer forming step of forming a layer containing particles;
A binding step of forming a layered structure in which the particles are bound to each other by curing the binding liquid after infiltrating a part of the layer with the binding liquid;
A removal step of removing a portion other than the layered structure from the layer including the layered structure, and a layered structure including the layer including the layered structure by alternately repeating the layer forming step and the binding step After the body is formed, the removal step is performed, and a modeling method in which a modeled object in the form of laminating the layered structure is formed,
When the (k + 1) -th layer (k is an integer of 1 or more) of the binding region is formed so as to protrude from the k-th layer binding region to the k-th layer non-binding region, In the binding step of the (k + 1) th layer, the first region includes a first region including a region immediately above the boundary between the binding region of the kth layer and the unbound region of the kth layer. The modeling method characterized by making the application amount of the binding liquid larger than in the second region other than the region. In the binding step of the first region of the (k + 1) th layer,
The modeling method according to claim 1, wherein on the unbound region of the k-th layer, the amount of the binding liquid applied is increased as the binding liquid application position approaches immediately above the boundary. In the binding step of the (k + 1) th layer,
The application amount per unit area on the surface of the (k + 1) th layer is binarized,
In the first region, the binding solution is applied in a first application amount,
The modeling method according to claim 1, wherein the binding liquid is applied to the second region with a second application amount smaller than the first application amount. In the binding step of the (k + 1) th layer,
Using a discharge head that discharges the binding liquid as droplets, while scanning the discharge head with respect to the (k + 1) th layer, a plurality of points are formed from the discharge head toward the (k + 1) th layer. Discharging the droplets at the same size,
The modeling method according to any one of claims 1 to 3, wherein in the first region, a discharge interval in one scan is shorter than that in the second region. Forming a layer containing the granules from a slurry containing hydrophobic granules, an aqueous solvent, and an amphiphilic solid polymer dissolved in the aqueous solvent;
In the removing step,
The modeling method according to claim 1, wherein a portion other than the layered structure is removed from the layer including the layered structure by flowing an aqueous liquid.

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