Method for producing three-dimensional object and three-dimensional object produced by melting / layer-by-layer stacking

Abstract

Provided is a method for producing a three-dimensional object by a melting / layer-by-layer stacking process using an object-forming material including a crystalline thermoplastic resin as a main component. In the method, the layers being stacked do not separate from the object-forming stage during object formation and a three-dimensional object having little deformation is obtained. 　This method for producing a three-dimensional object comprises producing a three-dimensional object by a melting / layer-by-layer stacking process using an object-forming material including a crystalline thermoplastic resin as a main component, while keeping the temperature of the atmosphere inside the chamber at [(melting point (mp) of the crystalline thermoplastic resin)-50°C] to [(the melting point (mp))-20°C].

Description

Method for manufacturing three-dimensional objects and fused deposition modeling of three-dimensional objects

[0001] This disclosure relates to a method for manufacturing three-dimensional objects and to fused deposition modeling (FDM) three-dimensional objects.

[0002] A 3D printer is a device that creates three-dimensional objects by sequentially layering materials based on three-dimensional design data created by a computer, and several methods are known. Among them, fused deposition modeling (FDM), which forms three-dimensional objects by heating and melting thermoplastic resin and layering it, is becoming widely popular not only for industrial use but also for personal use because the devices employing this method are inexpensive.

[0003] While resin materials containing thermoplastic resins such as polylactic acid and ABS resin are commonly used as molding materials in fused deposition modeling (FDM), the use of other thermoplastic resins as molding materials is being considered. For example, crystalline engineering plastics (crystalline thermoplastic resins) such as polybutylene terephthalate resin (hereinafter sometimes referred to as "PBT resin") and polyphenylene sulfide resin (hereinafter sometimes referred to as "PPS resin") have excellent heat resistance, mechanical properties, and chemical resistance. If such crystalline thermoplastic resins can be used as molding materials and molded by FDM, it would be useful because engineering plastics with desired shapes could be prepared in a simpler way. However, many crystalline engineering plastics have a fast crystallization rate, and furthermore, the shrinkage rate tends to increase with crystallization. Therefore, during FDM molding, the laminate may peel off the molding stage or deform, making it difficult to create three-dimensional objects using this method.

[0004] In response to such problems, for example, Patent Document 1 describes suppressing the warping of a shaped object using a filament in which a polycarbonate resin is blended with a polybutylene terephthalate resin. Further, Patent Document 2 describes a method of shaping in a wide temperature range by a hot melt lamination method using a filament composed of polybutylene terephthalate and a polyalkylene glycol block copolymer. However, since these technologies all use filaments containing a polycarbonate resin or a polyalkylene glycol as a main component, they are inferior in heat resistance and chemical resistance to molded products containing a crystalline thermoplastic resin as a main component.

[0005] International Publication No. 2022 / 138954 Japanese Unexamined Patent Application Publication No. 2016-055637

[0006] The present disclosure relates to a method for manufacturing a three-dimensional shaped object by a hot melt lamination method using a shaping material containing a crystalline thermoplastic resin as a main component, and an object of the present disclosure is to provide a method for manufacturing a three-dimensional shaped object in which peeling of the laminate from the shaping stage does not occur during shaping and the three-dimensional shaped object has little deformation.

[0007] As a result of intensive studies by the inventors of the present application, it has been found that the above problems can be solved by performing shaping while maintaining the chamber temperature within a specific temperature range in the hot melt lamination method. That is, the present disclosure includes the following aspects. [1] A method for manufacturing a three-dimensional shaped object, the manufacturing method including shaping a three-dimensional shaped object by a hot melt lamination method using a shaping material containing a crystalline thermoplastic resin as a main component, wherein the shaping is performed while maintaining the ambient temperature in the chamber at (melting point (mp) - 50°C) or higher and (melting point (mp) - 20°C) or lower of the crystalline thermoplastic resin.

[0008] According to the present disclosure, it is possible to provide a method for manufacturing a three-dimensional shaped object by a hot melt lamination method using a shaping material containing a crystalline thermoplastic resin as a main component, in which peeling of the laminate from the shaping stage does not occur during shaping and the three-dimensional shaped object has little deformation.

[0009] This is a conceptual diagram showing one aspect of the manufacturing method according to the first embodiment. These are photographs of the three-dimensional object of Example 1 during fabrication, after fabrication, and of the layered portion. These are photographs of the three-dimensional object of Comparative Example 2 during fabrication, after fabrication, and of the layered portion. These are photographs of the three-dimensional object of Example 3 during fabrication and after fabrication.

[0010] The following describes in detail one embodiment of the present disclosure. The present disclosure is not limited to the following embodiment and can be implemented with appropriate modifications, provided that these modifications do not impede the effects of the present disclosure. Each configuration and combination thereof in each embodiment is an example, and additions, omissions, substitutions, and other modifications can be made as appropriate, provided that these modifications do not deviate from the spirit of the present disclosure. The present disclosure is not limited by the embodiments. Each aspect disclosed herein can be combined with any other features disclosed herein. If a particular description given for one embodiment also applies to another embodiment, that description may be omitted in the other embodiments. In this disclosure, the expression "X to Y" for numerical ranges means "X or more and Y or less". In this specification, "3D object" refers to an object after the molding is complete, and "layer" refers to an object during the molding process.

[0011] [Method for Manufacturing Three-Dimensional Objects] The first embodiment of this disclosure is a method for manufacturing three-dimensional objects. The method for manufacturing three-dimensional objects according to the first embodiment includes manufacturing a three-dimensional object by fused deposition modeling using a molding material mainly composed of a crystalline thermoplastic resin, wherein the manufacturing is performed while maintaining the ambient temperature in the chamber at a temperature between (melting point (mp) - 50°C) and (melting point (mp) - 20°C) of the crystalline thermoplastic resin. According to the manufacturing method according to the first embodiment, a three-dimensional object can be obtained in which the laminate does not peel off from the molding stage during manufacturing and which is less deformed.

[0012] <Fused Deposition Modeling> Fused deposition modeling is a method of creating three-dimensional objects (3D molded objects) by melting filaments, which mainly consist of thermoplastic resin, at high temperatures and layering them.

[0013] Figure 1 is a conceptual diagram showing one aspect of the manufacturing method according to the first embodiment. In Figure 1, the 3D printing machine 10 for fused deposition modeling has a configuration in which a heating and melting machine 3 and a printing stage 5 are arranged inside a chamber 4. The heating and melting machine 3 is filled with a printing material 1, and the printing material 1 is melted and extruded from the nozzle 2 to create a three-dimensional object having a desired shape. The details of the manufacturing method according to the first embodiment will be described below with reference to the conceptual diagram in Figure 1.

[0014] <Forming Material> (Crystalline Thermoplastic Resin) The manufacturing method according to the first embodiment includes forming a three-dimensional object by fused deposition modeling using a forming material 1 containing a crystalline thermoplastic resin as the main component. Here, "contains as the main component" means that the proportion of crystalline thermoplastic resin to the total mass of the forming material 1 is more than 50% by mass. From the viewpoint of heat resistance and chemical resistance of the final three-dimensional object, the proportion of crystalline thermoplastic resin in the forming material 1 is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more. In one embodiment, the proportion of crystalline thermoplastic resin to the total resin components in the forming material may be 100% by mass.

[0015] In one embodiment, from the viewpoint of easily obtaining a three-dimensional molded object with excellent heat resistance, the crystalline thermoplastic resin contained in the molding material 1 is preferably one with a melting point of 160°C or higher, more preferably one with a melting point of 200°C or higher, and even more preferably one with a melting point of 250°C or higher. In this specification, the melting point of the crystalline thermoplastic resin is the value measured by a micro-melting point measuring device (for example, the MP-100X manufactured by Yanako Machinery Development Laboratory Co., Ltd.).

[0016] In one embodiment, the molding material 1 preferably contains as a main component a crystalline thermoplastic resin having a melting point of 160°C or higher and a shrinkage rate of 0.5% or higher as measured in accordance with ISO 294-4. In one embodiment, it is more preferable that the molding material 1 contains as a main component a crystalline thermoplastic resin having a melting point of 160°C or higher and a shrinkage rate of 1% or higher as measured in accordance with ISO 294-4. Examples of such crystalline thermoplastic resins include liquid crystalline resin (melting point 280°C, shrinkage rate 0.9%), polyacetal resin (melting point 165°C, shrinkage rate 2.3%), PBT resin (melting point 225°C, shrinkage rate 2.1%), and polyphenylene sulfide resin (melting point 280°C, shrinkage rate 1.4%). Such crystalline thermoplastic resins have a fast crystallization rate and high degree of crystallinity, and therefore have excellent chemical resistance and high heat resistance. On the other hand, when fabricating using fused deposition modeling (FDM), the laminate tends to peel off the fabrication stage 5, and delamination between layers is also likely to occur. According to the manufacturing method of the first embodiment, even when using a fabrication material 1 that mainly contains such a crystalline thermoplastic resin, the laminate is less likely to peel off the fabrication stage 5 during fabrication, delamination between layers is less likely to occur, and a three-dimensional object with less deformation is more likely to be obtained.

[0017] In one preferred embodiment, the molding material mainly comprises a liquid crystalline resin. In one preferred embodiment, the molding material mainly comprises a PBT resin.

[0018] As described above, when fabricating using fused deposition modeling (FDM) with a molding material 1 mainly composed of crystalline thermoplastic resin, the laminate may peel off the fabrication stage 5, or delamination may occur between the layers of the final three-dimensional object. In FDM, bonding occurs through heat conduction between the upper (high temperature) and lower (low temperature) beads during fabrication. When the lower bead comes into contact with the upper bead, the temperature rises, causing the polymer chains of each bead to intertwine, increasing the bonding strength. The inventors of this application have found that if the ambient temperature inside the chamber is low, solidification occurs before this polymer chain entanglement can progress, making it easier for the beads to peel off. They have also found that maintaining a high ambient temperature inside the chamber (a temperature within a certain range relative to the melting point of the crystalline thermoplastic resin) promotes polymer chain entanglement and improves the strength between the beads. In other words, in the manufacturing method according to the first embodiment, the ambient temperature of the chamber 4 is maintained at or above (melting point (mp) - 50°C) or below (melting point (mp) - 20°C) of the crystalline thermoplastic resin during molding. Note that "ambient temperature of the chamber 4" refers to the temperature T: (°C) inside the chamber 4 in Figure 1. Furthermore, in the manufacturing method according to the first embodiment, the temperature T inside the chamber 4 is maintained within the range of (melting point (mp) - 50°C) or below (melting point (mp) - 20°C) of the crystalline thermoplastic resin until molding is completed. This suppresses the peeling of the laminate from the molding stage 5 and strengthens the bonding strength between the layers. If the temperature T inside the chamber 4 is above (melting point (mp) - 50°C) of the crystalline thermoplastic resin, it is possible to suppress the peeling of the laminate from the molding stage 5, which would prevent molding, and to prevent peeling between layers. In addition, it suppresses deformation due to shrinkage of the three-dimensional molded object, resulting in a highly accurate three-dimensional molded object. If the temperature T is below the melting point (mp) - 20°C of the crystalline thermoplastic resin, deformation of the laminated resin due to its own weight or nozzle scanning can be suppressed, and a highly accurate three-dimensional object can be obtained. As a method for controlling the temperature T inside the chamber 4 to the above range, one method is to detect the temperature inside the chamber using a sensor such as a thermocouple and perform PID control. Furthermore, from the viewpoint of making it easier to control the temperature T inside the chamber 4 to the above range, it is preferable to use a device that supports high temperature control, such as the "ZORTRAX ENDUREAL" manufactured by ZORTRAX, as the 3D printing machine 10.

[0019] The temperature T can be arbitrarily adjusted within the range of (melting point (mp) - 50°C) or higher and (melting point (mp) - 20°C) or lower for the crystalline thermoplastic resin. In one embodiment, the temperature T may be (melting point (mp) - 45°C) or higher and (melting point (mp) - 30°C) or lower for the crystalline thermoplastic resin. In one embodiment, if the crystalline thermoplastic resin includes PBT resin, the temperature T may be (melting point (mp) - 45°C) or higher and (melting point (mp) - 35°C) or lower. In one embodiment, if the crystalline thermoplastic resin includes liquid crystalline resin, the temperature T may be (melting point (mp) - 50°C) or higher and (melting point (mp) - 30°C) or lower.

[0020] (Additives) In one embodiment, the molding material 1 may contain additives other than crystalline thermoplastic resin. Examples of additives include various inorganic fillers, antioxidants and stabilizers, flame retardants, colorants, etc. These may be used individually or in combination of two or more.

[0021] In the manufacturing method according to the first embodiment, the molding material 1 is preferably a filament that can be used in fused deposition modeling. The cross-section of such a filament is preferably circular, and it can be prepared by using a single-screw or multi-screw extruder with any die diameter and slowly cooling it in a hot water bath.

[0022] In the manufacturing method according to the first embodiment, the temperature of the nozzle 2 is preferably (melting point (mp) + 10°C) or higher and (melting point (mp) + 50°C) or lower, and more preferably (melting point (mp) + 15°C) or higher and (melting point (mp) + 45°C) or lower, from the viewpoint of suppressing resin degradation. Furthermore, the lamination pitch is not particularly limited, but from the viewpoint of bead adhesion, it is preferably 0.05 to 0.80 mm and more preferably 0.10 to 0.40 mm.

[0023] In the manufacturing method according to the first embodiment, when molding a crystalline thermoplastic resin having a melting point of 160°C or higher, the temperature of the molding stage is preferably 145°C or higher (melting point of the crystalline thermoplastic resin (mp) - 15°C) or lower, from the viewpoint of easily suppressing delamination.

[0024] After fabrication using the method described above, a three-dimensional object with the desired shape can be obtained by removing the layered material from the fabrication stage.

[0025] [Fused Deposition Modeling] A second embodiment of this disclosure relates to a fused deposition modeling (FDM) modeling product mainly composed of a crystalline thermoplastic resin. That is, the three-dimensional modeling product according to the second embodiment is a three-dimensional modeling product made by fused deposition modeling and mainly composed of a crystalline thermoplastic resin. The three-dimensional modeling product according to the second embodiment is preferably made by the manufacturing method according to the first embodiment. If the three-dimensional modeling product according to the second embodiment is made by the manufacturing method according to the first embodiment, it is likely to be a three-dimensional modeling product with no delamination between layers and with little deformation.

[0026] [Applications] According to the manufacturing method of the first embodiment, a three-dimensional molded object containing crystalline thermoplastic resin as the main component and exhibiting minimal deformation can be obtained. Similarly, the three-dimensional molded object according to the second embodiment also contains crystalline thermoplastic resin as the main component and exhibits minimal deformation. Such three-dimensional molded objects can be suitably used in a variety of applications, such as automotive resin parts, small, high-heat-resistant connectors, high-heat-resistant gears, prosthetic arms, prosthetic legs, artificial bones, dentures, artificial hearts, and other medical applications.

[0027] A non-limiting list of exemplary embodiments of the present disclosure and combinations of exemplary embodiments is given below: [1] A method for manufacturing a three-dimensional object, the manufacturing method comprising forming a three-dimensional object by fused deposition modeling using a molding material mainly composed of a crystalline thermoplastic resin, wherein the forming is performed while maintaining the ambient temperature in the chamber at or above (melting point (mp) - 50°C) and or below (melting point (mp) - 20°C) of the crystalline thermoplastic resin. [2] The method for manufacturing a three-dimensional object according to [1], wherein the molding material mainly comprises a crystalline thermoplastic resin having a melting point (mp) of 160°C or higher and a shrinkage rate of 1% or more as measured in accordance with ISO 294-4. [3] The method for manufacturing a three-dimensional object according to [1] or [2], wherein the molding material mainly comprises a polybutylene terephthalate resin. [4] The method for manufacturing a three-dimensional object according to [1], wherein the molding material mainly comprises a liquid crystalline resin. [5] A fused deposition modeled three-dimensional object comprising a crystalline thermoplastic resin as the main component. [6] A method for producing a three-dimensional object according to any one of [1] to [4], wherein the molding material comprises a crystalline thermoplastic resin having a melting point (mp) of 160°C or higher and a shrinkage rate of 0.5% or higher as measured in accordance with ISO 294-4.

[0028] The present disclosure will be further illustrated by the following examples, but these examples will not limit the interpretation of the present disclosure.

[0029] [Example 1] A filament made from PBT resin (manufactured by Polyplastics Co., Ltd., product name "Duranex® 700FP", melting point 225°C) was placed in a 3D printer (manufactured by ZORTRAX, product name "ZORTRAX ENDUREAL") with a chamber capable of heating up to 200°C. Then, the nozzle temperature was maintained at 260°C, the chamber atmosphere temperature at 190°C (melting point -35°C), and the printing stage at 160°C or higher. Two rectangular prism-shaped objects were created at a printing speed of 40 mm / s, a nozzle diameter of 0.4 mm, and a layer thickness of 0.2 mm. Photographs of the 3D objects (width 80 mm x depth 4 mm x height 8 mm) during and after printing, as well as enlarged photographs of the 3D objects, are shown in Figure 2. Figure 2 shows that the layered material was fabricated without detaching from the build stage, and there was no delamination between layers. Table 1 shows the evaluation results for delamination from the build stage during fabrication, delamination between layers after fabrication, and warping deformation of the three-dimensional object.

[0030] [Example 2] A three-dimensional object was obtained under the same conditions as in Example 1, except that the ambient temperature of the chamber was adjusted to 180°C (melting point -45°C). As a result, the layers did not peel off from the build stage, and there was no peeling between layers. There was also no warping of the three-dimensional object.

[0031] [Comparative Examples 1-2] Except for adjusting the ambient temperature of the chamber to 90°C (melting point -135°C) (Comparative Example 1) and 150°C (melting point -75°C), three-dimensional objects were obtained under the same conditions as in Example 1. Figure 3 shows photographs of the three-dimensional object (80 mm wide x 4 mm deep x 8 mm high) of Comparative Example 2 during and after printing, as well as a magnified photograph of the three-dimensional object. From Figure 3, it can be seen that the layered material of the three-dimensional object of Comparative Example 2 peeled off from the printing stage, and further peeling occurred between the layers after printing (P in Figure 3), and the object was also deformed. Comparative Example 1 yielded the same results as Comparative Example 2.

[0032] [Example 3] A molding material (filament diameter: φ1.75 mm) made by molding liquid crystalline resin (manufactured by Polyplastics Co., Ltd., product name "Laperos® A950", melting point 280°C) into a filament was used with a 3D printer (manufactured by Fusion Technology Co., Ltd., product name "FUNMAT"). The PRO610HT was set up. Then, the nozzle temperature was maintained at 260°C, the chamber atmosphere temperature at 230°C (melting point -50°C), and the build stage at 160°C or higher. Two rectangular prism-shaped objects were created at a build speed of 60 mm / s, a nozzle diameter of 0.4 mm, and a layer thickness of 0.2 mm. Photographs of the three-dimensional objects (80 mm wide x 4 mm deep x 8 mm high) during and after build are shown in Figure 4. From Figure 4, it can be seen that the layers were built without detaching from the build stage. Table 1 shows the evaluation results of detachment from the build stage during build, detachment between layers after build, and warping deformation of the three-dimensional objects.

[0033] [Example 4] A three-dimensional object was obtained under the same conditions as in Example 3, except that the ambient temperature of the chamber was adjusted to 250°C (melting point -30°C). As a result, the layers did not peel off from the build stage, and there was no peeling between layers. There was also no warping of the three-dimensional object.

[0034]

[0035] As shown in Table 1, it was found that the manufacturing method according to the first embodiment does not cause peeling of the laminate from the printing stage during molding, and a three-dimensional object with minimal deformation can be obtained.

[0036] According to the manufacturing method of the first embodiment, a three-dimensional molded object can be obtained that mainly contains a crystalline thermoplastic resin and exhibits minimal deformation. Such a three-dimensional molded object can be suitably used in a variety of applications, such as automotive resin parts, small, high-heat-resistant connectors, high-heat-resistant gears, prosthetic arms, prosthetic legs, artificial bones, dentures, artificial hearts, and other medical applications, thus possessing industrial applicability.

[0037] 1. Molding material 2. Nozzle 3. Heating and melting machine 4. Chamber 5. Molding stage 10. 3D 3D printer T. Ambient temperature inside chamber 4 (°C) P. Delamination between layers

Claims

1. A method for manufacturing a three-dimensional object, wherein the manufacturing method includes forming a three-dimensional object by fused deposition modeling using a molding material mainly composed of a crystalline thermoplastic resin, and the forming is performed while maintaining the ambient temperature in the chamber at or above (melting point (mp) - 50°C) and or below (melting point (mp) - 20°C) of the crystalline thermoplastic resin.

2. The method for producing a three-dimensional object according to claim 1, wherein the molding material mainly comprises a crystalline thermoplastic resin having a melting point (mp) of 160°C or higher and a shrinkage rate of 1% or higher as measured in accordance with ISO 294-4.

3. The method for manufacturing a three-dimensional object according to claim 1 or 2, wherein the molding material mainly comprises polybutylene terephthalate resin.

4. The method for manufacturing a three-dimensional object according to claim 1, wherein the molding material mainly comprises a liquid crystalline resin.

5. A fused deposition modeled material containing crystalline thermoplastic resin as its main component.

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