JP7549219B2 - Manufacturing method of the object - Google Patents

Description

The present invention relates to a method for manufacturing a molded object formed by additive manufacturing.

Additive manufacturing is a method of creating a three-dimensional object with a specified structure, in which a fluid material is extruded, solidifies, and then further material is layered on top of it to create the object. Although UV curing and fused deposition modeling have been proposed as additive manufacturing methods, fused deposition modeling is widely used due to its simple device structure.

There are a variety of three-dimensional structures that can be additively manufactured, and some of them include parts that cannot be manufactured unless they are supported by something else during the manufacturing process. Therefore, when additively manufacturing an object, it is common to also additively manufacture a support that supports at least a part of the object, and then dissolve and remove the support after manufacturing is complete (for example, Patent Document 1).

JP 2018-099788 A

However, the method of Patent Document 1 has the problem that the object and the support are formed together, which means that the forming time is increased by the time required for the support.

The present invention was made in consideration of these circumstances, and aims to provide a method for manufacturing objects that can shorten the molding time.

According to the present invention, there is provided a method for manufacturing a molded object, comprising an additive manufacturing process and a removal process, in which the additive manufacturing process forms an integrated object in which a molded object made of resin and the support are integrated by stacking a single-layer structure of resin in a modeling area in which a previously prepared support is arranged, and the removal process separates the integrated object into the molded object and the support, thereby removing the support from the integrated object.

In the additive manufacturing process of the present invention, a support prepared in advance is used to form an integrated object in which the model and the support are integrated, so the time required for modeling the support is not required, making it possible to shorten the modeling time.

Preferably, in the method described above, the additive manufacturing process is carried out by fused deposition modeling.
Preferably, in the method described above, the support has a recess at the site where the single layer structure is to be formed.
Preferably, in the method described above, the single-layer structure is formed by discharging a resin in a fluid state while moving a head and solidifying the discharged resin, and the opening diameter of the recess is smaller than the diameter of the discharge port of the head.
Preferably, in the above-described method, the resin constituting the support and the resin constituting the shaped object have a common monomer.
Preferably, in the method described above, the support separated in the removing step is reused in an additive manufacturing step for producing a next shaped object.

FIG. 1A is a plan view of a shaped object 1, and FIG. 1B is a cross-sectional view taken along line AA in FIG. 1A. FIG. 2A is a perspective view showing the three-dimensional mesh structure 2, and FIG. 2B is a perspective view showing the single layer structures 6, 7, and 8. As shown in FIG. FIG. 3A is a cross-sectional view corresponding to FIG. 1B showing the additive manufacturing process, and FIG. 3B is an enlarged view of region B in FIG. 3A. 4A is a cross-sectional view corresponding to FIG. 1B showing the integrated body 9, and FIG. 4B shows the state after the integrated body 9 of FIG. 4A has been separated into the support body 3 and the shaped object 1. As shown in FIG.

The following describes the embodiments of the present invention. The various features shown in the embodiments below can be combined with each other. In addition, each feature can be an invention independently.

1 and 2 show an example of a molded object 1 that can be manufactured by a manufacturing method for a molded object 1 according to one embodiment of the present invention. The molded object 1 is, for example, a breast body such as a bra pad or an artificial breast. The molded object 1 has an upper surface 1a and a lower surface 1b. When the molded object 1 is a breast body, the upper surface 1a has a shape that imitates the outer shape of a breast, and the lower surface 1b has a shape that fits the outer surface of the body of a user on whom the molded object 1 is worn. The lower surface 1b is provided with a recess 1c that has a complementary shape to a protrusion of the body.

The model 1 is formed by additive manufacturing. Additive manufacturing is a method of forming the model 1 by stacking single-layer structures that form part of the model 1. The additive manufacturing may be performed by any method such as UV curing or fused deposition modeling, but fused deposition modeling, in which resin melted by heat is stacked, is preferred.

In one example, the molded object 1 has a three-dimensional mesh structure 2 as shown in FIG. 2A. The three-dimensional mesh structure 2 is a mesh-like structure formed by stacking single-layer structures composed of linear resin 2a. When the molded object 1 has such a structure, the rigidity of the molded object 1 can be changed by changing the interval between adjacent linear resins 2a or by changing the thickness of the linear resins 2a. When the molded object 1 is a breast body, it is necessary to make the molded object 1 have a rigidity according to the user's request, and a molded object 1 having a three-dimensional mesh structure 2 can easily realize such a request. In addition, there is a request to make the rigidity of a part of the molded object 1 higher or lower than the other parts, and the above request can be easily realized by narrowing or widening the interval between adjacent linear resins 2a in a part of the three-dimensional mesh structure 2.

The diameter of the linear resin 2a is, for example, 0.5 to 6.0 mm, and preferably 1.0 to 4.0 mm. Specifically, the diameter may be, for example, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, or 6.0 mm, or may be within a range between any two of the numerical values exemplified here.

In one example, the three-dimensional mesh structure 2 is formed by repeatedly stacking the single layer structures 6, 7, and 8 shown in FIG. 2B in this order. The single layer structure 6 has linear resin 6a composed of multiple parallel lines spaced apart from each other. The single layer structure 7 has linear resin 7a composed of multiple parallel lines spaced apart from each other. The single layer structure 8 has linear resin 8a composed of multiple parallel lines spaced apart from each other. The linear resins 6a, 7a, and 8a are arranged to extend in directions shifted by 60 degrees from each other.

The resin constituting the molded object 1 is not particularly limited, and examples include ABS, polyolefin (e.g., polypropylene), polyester, and thermoplastic elastomer. When the molded object 1 is required to have high flexibility, such as a breast body, the resin constituting the molded object 1 is preferably a thermoplastic elastomer.

Examples of thermoplastic elastomers include styrene-based elastomers, olefin-based elastomers, and acrylic-based elastomers. It is preferable that this thermoplastic elastomer contains a styrene-based elastomer. Since styrene-based elastomers have high flexibility, the flexibility of the thermoplastic elastomer increases when the thermoplastic elastomer contains a styrene-based elastomer. The proportion of the styrene-based elastomer in the thermoplastic elastomer is preferably 50 to 100% by mass, more preferably 80 to 100% by mass, and specifically, for example, 50, 60, 70, 80, 90, or 100% by mass, and may be within a range between any two of the numerical values exemplified here.

A styrene-based elastomer is a thermoplastic elastomer having styrene units, and examples thereof include a blend of one or more selected from styrene-based copolymers (e.g., styrene-ethylene-styrene block copolymer (SES), styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), styrene-butadiene rubber (SBR)), hydrogenated styrene-based copolymers (e.g., styrene-ethylene propylene-styrene block copolymer (SEPS), styrene-ethylene butylene-styrene block copolymer (SEBS), styrene-butylene butadiene-styrene block copolymer (SBBS), hydrogenated styrene-butadiene rubber (HSBR)), etc.

The Shore A hardness of the thermoplastic elastomer is preferably 0 to 10, specifically, for example, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and may be within a range between any two of the values exemplified here. When the Shore A hardness is within this range, a molded object with excellent flexibility is obtained. The Shore A hardness is measured based on JIS K6253.

1-2. Method for Manufacturing the Model 1 Next, a method for manufacturing the model 1 according to an embodiment of the present invention will be described. This method includes an additive manufacturing process and a removal process. Each process will be described below.

(1) Additive Manufacturing Process In the additive manufacturing process, as shown in FIG. 3, a single-layer structure of resin 4 is laminated in a manufacturing area R in which a pre-prepared support 3 is arranged, thereby forming an integrated object 9 in which a molded object 1 made of resin 4 and the support 3 are integrated, as shown in FIG. 4A.

The additive manufacturing process can be performed by any additive manufacturing method. In one example, a single-layer structure can be produced by discharging resin in a fluid state while moving the head 5, and solidifying the discharged resin 4. In the fused deposition modeling method, resin that has been made fluid by heating is discharged, and the discharged resin in a fluid state is solidified by cooling. In the UV curing method, the discharged resin in a fluid state is solidified by UV irradiation.

In one example, in the fused deposition modeling method, as shown in FIG. 3, the resin 4 melted in the head 5 is discharged from the discharge port 5a at the tip of the head 5 while the head 5 is moved in the modeling region R to form the model 1. The form of the resin supplied to the head 5 is not limited, and may be a filament or a pellet. When the resin is in the form of a filament, the filament can be moved downstream by rotating the gear built into the head 5 while engaging the gear, thereby discharging the resin 4 melted in the head 5. When the resin is in the form of a pellet, a screw-type extruder having a built-in screw can be used as the head 5, and the resin 4 melted in the head 5 can be discharged by rotating the screw. When the resin is very flexible, such as a thermoplastic elastomer, it may be difficult to move the filament downstream by rotating the gear, so in this case, it is preferable that the head 5 is a screw-type extruder.

The temperature of the resin 4 immediately after it is discharged from the discharge port 5a is defined as the modeling temperature. The modeling temperature is preferably 120 to 230°C. This is because in this case, the resin 4 is likely to be sufficiently solidified when cooled, and deterioration of the modeling material due to heating is unlikely to occur. The modeling temperature is specifically, for example, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, or 230°C, and may be within a range between any two of the numerical values exemplified here.

Since the object 1 has a recess 1c, in order to form a portion 1d (shown in FIG. 1B) above the recess 1c, it is necessary to prepare a support 3 and form the portion 1d on the support 3.

In Patent Document 1, the model and the support are modeled together, but this method has the problem that the modeling time is longer due to the support. Therefore, in this embodiment, the modeling time is shortened by using a support 3 that is prepared in advance.

The method for forming the support 3 is not particularly limited, and it can be formed by additive manufacturing, injection molding, or the like. When the support 3 is formed by injection molding, it is easy to smooth the surface of the support 3, and in this case, the inner surface of the recess 1c of the molded object 1 can be smoothed. When the molded object 1 is a breast body, the inner surface of the recess 1c is the surface that comes into contact with the body, and so by smoothing this surface, the quality of the breast body can be improved.

The melting point of the resin constituting the support 3 (hereinafter, "support resin") is preferably higher than the melting point of the resin 4. In this case, by modeling at a temperature between the melting points of the support resin and the resin 4, it is possible to model the object 1 without melting the support 3. In this case, since the support 3 does not melt, the support 3 separated in the removal process described below can be reused in the additive manufacturing process for producing the next object. The melting point of the support resin is preferably higher than the modeling temperature. In this case, it is possible to model the object 1 without melting the support 3. In this specification, "melting point" means the melting peak temperature Tpm measured in accordance with JIS K 7121:2012.

As shown in FIG. 3B, the support 3 has an inclined surface 3a. The inclined surface 3a may be flat or curved. When the object 1 is a breast body, it is preferable to provide an inclined surface on the inner surface of the recess 1c to make the object 1 fit the body. By providing the inclined surface 3a on the support 3, it is possible to provide an inclined surface on the inner surface of the recess 1c as well. The inclination angle of the inclined surface 3a with respect to the horizontal plane is, for example, 5 to 85 degrees, and preferably 10 to 80 degrees. Specifically, this inclination angle may be, for example, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, or 85 degrees, or may be within a range between any two of the numerical values exemplified here.

However, when the resin 4 is ejected onto the support 3, the resin 4 may slip on the support 3, making it impossible to obtain a molded object 1 of the desired shape. Therefore, it is preferable to provide a slippage suppression structure that suppresses the resin 4 from slipping on the support 3.

One example of a slip-suppressing configuration is that the support resin and resin 4 have a common monomer. Resins having a common monomer (i.e., resins of the same type) generally have high affinity, so by using such a combination of resins, the slippage of resin 4 is suppressed. For example, when resin 4 is a styrene-based elastomer, it is preferable to use a styrene-based elastomer or a styrene-based resin other than an elastomer as the support resin. The proportion of the common monomer between the support resin and resin 4 is, for example, 50 to 100 mass%, and specifically, for example, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100 mass%, and may be within a range between any two of the numerical values exemplified here.

Another example of a slip suppression configuration is that the absolute value of the difference in Hansen solubility parameters between the support resin and resin 4 is ΔSP, where ΔSP is a value of 1.3 or less. ΔSP is an index showing the affinity between resins, and the smaller the ΔSP value, the higher the affinity between the support resin and resin 4. Therefore, by using a combination of resins with a ΔSP value of 1.3 or less, slippage of resin 4 is suppressed. ΔSP is preferably 1.0 or less, more preferably 0.5 or less, and specifically, for example, 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, and may be within a range between any two of the numerical values exemplified here.

As shown in FIG. 3B, another example of a slip prevention configuration is to provide a recess 3b in the portion of the support 3 where the single-layer structure is formed (the inclined surface 3a in FIG. 3B). In this case, the resin 4 enters the recess 3b and solidifies, so that the resin 4 engages with the support 3 and suppresses slippage of the resin 4. When this slip prevention configuration is adopted, even if the affinity between the support resin and the resin 4 is low, the slippage of the resin 4 is suppressed, so there is an advantage that the range of material selection for the support 3 is widened. The opening diameter of the recess 3b is preferably smaller than the diameter of the discharge port 5a. In this case, the amount of resin 4 that enters the recess 3b is not too large, and the deformation of the shape caused by the resin 4 entering the recess 3b is suppressed.

When the support 3 is a porous body, the pores of the porous body function as the recesses 3b. The porous body may be a material such as zeolite that is itself porous, or may have a three-dimensional mesh structure 2 formed by additive manufacturing as shown in FIG. 2. When the support 3 is a molded body formed using a mold, the recesses 3b may be formed by transferring the protrusions of the mold.

As shown in FIG. 3B, another example of a slippage suppression configuration is to set G/D to 0.5 or less when forming a layer in contact with the support 3, where G is the distance between the head 5 and the support 3 on the center line 5b of the discharge port 5a of the head 5 and D is the diameter of the discharge port of the head 5. G/D is generally set to about 0.8, but when G/D is set to such a value, the resin 4 tends to slip on the support 3. In order to suppress the slippage of the resin 4, it is possible to increase the affinity between the support resin and the resin 4, but in that case, there is an issue that the freedom of selection of the support resin is narrowed.

To solve this problem, this configuration employs a G/D of 0.5 or less. With this G/D value, the ejected resin 4 is pressed strongly against the support 3, increasing the adhesion between the resin 4 and the support 3 and suppressing slippage of the resin 4. Therefore, by adopting this configuration, the range of materials that can be selected for the support 3 is expanded. G/D is, for example, 0.1 to 0.5, and more specifically, for example, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, and 0.50, and may be within a range between any two of the numerical values exemplified here.

When forming the next monolayer structure on the lower monolayer structure, the distance between the head 5 and the lower layer is G1, and G/G1 is preferably 0.1 to 1, and more preferably 0.3 to 0.8. G and G1 indicate the so-called modeling pitch. In order to facilitate separation of the support 3 and the modeled object 1, the modeling pitch when forming the monolayer structure on the support 3 is generally set to be larger than the modeling pitch when forming the next monolayer structure on the lower monolayer structure, that is, G/G1 is generally set to be larger than 1. However, in this configuration, the slippage of the resin 4 on the support 3 is suppressed by setting G/G1 to 1 or less. Specifically, G/G1 is, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1.0, and may be within a range between any two of the numerical values exemplified here.

This configuration is particularly effective when used in combination with a configuration in which a recess 3b is provided in the support 3. In this case, the resin 4 can easily enter the recess 3b, and slippage of the resin 4 can be more effectively suppressed.

(2) Removal Step In the removal step, the integrated object 9 shown in Fig. 4A is separated into the support 3 and the shaped object 1 as shown in Fig. 4B, thereby removing the support 3 from the integrated object 9. In this way, the shaped object 1 is obtained.

If at least one of the support resin and resin 4 is a highly flexible resin such as an elastomer, the above separation can be achieved by deforming the support 3 or the molded object 1. If both the support 3 and resin 4 are highly rigid, the above separation can be achieved by applying a force in a direction that pulls the support 3 and the molded object 1 away from each other. For example, the above separation can be achieved by poking the molded object 1 with an ejector pin provided on the support 3 or an area surrounding it while the support 3 is fixed to another member.

The support 3 removed in the removal process can be reused in the additive manufacturing process for manufacturing the next model 1. For this reason, it is preferable to perform the above separation in a manner that does not damage the support 3. Furthermore, by reusing the support 3, it is possible to reduce the time and cost required for manufacturing the support 3.

2. Other embodiments In the above embodiment, the support 3 having the inclined surface 3a and the recessed portion 3b is used, but a support 3 without the inclined surface 3a or a support 3 without the recessed portion 3b may be used.
In the above embodiment, G/D is 0.5 or less, but G/D may be greater than 0.5. In this case, G/D is, for example, 0.1 to 1, specifically, for example, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 1.00, and may be within a range between any two of the numerical values exemplified here.

Reference Signs List 1: Modeled object 1a: Upper surface 1b: Lower surface 1c: Recess 1d: Part 2: Three-dimensional mesh structure 2a: Linear resin 3: Support 3a: Inclined surface 3b: Recess 4: Resin 5: Head 5a: Discharge port 5b: Center line 6: Single-layer structure 6a: Linear resin 7: Single-layer structure 7a: Linear resin 8: Single-layer structure 8a: Linear resin 9: Integrated object R: Modeling region

Claims (5)

A method for manufacturing a shaped object, comprising the steps of:
The method includes an additive manufacturing process and a removal process,
In the additive manufacturing process, a resin monolayer structure is laminated in a modeling region in which a support body prepared in advance is disposed, thereby forming an integrated object in which a modeled object made of the resin and the support body are integrated,
In the removing step, the support is removed from the integrated body by separating the integrated body into the shaped object and the support ,
The method of claim 1, wherein the support has a recess on an inclined surface where the monolayer structure is formed . 2. The method of claim 1 ,
The method, wherein the additive manufacturing process is performed by fused deposition modeling. 3. The method of claim 1 or claim 2 ,
The single-layer structure is formed by discharging a resin in a fluid state while moving a head and solidifying the discharged resin,
A method in which an opening diameter of the recess is smaller than a diameter of an ejection port of the head. The method according to any one of claims 1 to 3 ,
A method, wherein a resin constituting the support and a resin constituting the shaped object have a common monomer. The method according to any one of claims 1 to 4 ,
The support separated in the removing step is reused in an additive manufacturing step for producing a next object.