Manufacturing method of resin molded object

Abstract

A method for producing a resin molded product, which can easily produce a high-quality resin molded product of desired dimensions, is provided. [Solution] A manufacturing method for producing a three-dimensional resin object W, comprising a modeling process in which resin material is layered using a 3D printer to form a rough object W1, and a removal process in which unnecessary parts of the rough object W1 are removed to form the resin object W.

Description

[Technical field]

[0001] The present invention relates to a method for producing a resin molded object. [Background technology]

[0002] Regarding resin objects used in various products, when making prototypes during the product development stage, for example, they are usually made by cutting existing resin material, for example, resin material formed into a plate or rod shape by extrusion molding or the like.

[0003] However, in the method of cutting plate-shaped resin materials, the types and colors of resins that can be used for prototyping are limited because there are few types of resin materials for cutting that are generally available. In addition, the shapes of resin materials that are generally available are plates or bars, and the resin materials that can be used to produce or prototype relatively large items by cutting are extremely limited. Therefore, when producing samples by cutting resin, it is not possible to freely select the type and color of resin as the material, and it is often not possible to produce with the material that is desired to be used in mass production or the material that is the subject of consideration for mass production. As a result, it is not possible to produce prototypes to evaluate the performance of resin molded products when mass-produced and commercialized, which is an obstacle to mass-produced products and products by resin molding.

[0004] For this reason, when it is necessary to properly evaluate the strength and other performance of a resin molded object when it is mass-produced and commercialized, a mold is made in the same way as for mass production, and a prototype is injection-molded using the resin material to be used.

[0005] For example, a method is known in which a prototype made of the same material as a regular product can be molded in a short delivery time at low cost by using a simple mold (see, for example, Patent Document 1).

[0006] However, the method disclosed in Patent Document 1 still requires the production of a mold, just as in the case of mass production and commercialization, and takes longer, more cost, and more effort than, for example, prototyping by cutting. Also, in such an injection molding method, there is a limit to the size of the resin material that can be molded because voids (so-called voids) inevitably occur inside the resin when the molten resin is cooled in the mold. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2014-65152 A Summary of the Invention [Problem to be solved by the invention]

[0008] Therefore, one object of the present invention is to provide a method for producing a resin molded object, which can easily produce a resin molded object of good quality and having desired dimensions. [Means for solving the problem]

[0009] A manufacturing method for a resin object according to an embodiment of the present invention is a manufacturing method for a resin object for manufacturing a three-dimensional resin object, and includes a modeling process for forming a rough object by stacking resin material using a modeling object manufacturing apparatus, and a removal process for removing unnecessary parts of the rough object to form a resin object.

[0010] In the above-described method for manufacturing a resin object, the object manufacturing device may be a fused deposition model 3D printer.

[0011] In the above-described method for producing a resin molded object, the resin material may be a thermoplastic resin in a pellet form.

[0012] In the above-described method for manufacturing a resin object, in the modeling step, the resin material may be discharged while moving a nozzle of a model manufacturing apparatus along a space-filling curve on an arbitrary two-dimensional plane of finite depth.

[0013] In the above-described method for manufacturing a resin object, in the modeling step, the resin material may be discharged while moving a nozzle of a model manufacturing device along a closed curve.

[0014] In the above-described method for manufacturing a resin object, in the modeling step, the resin material may be discharged while moving a nozzle of a model manufacturing device in a single stroke.

[0015] In the above-described method for manufacturing a resin model, in the modeling step, the resin material may be overlapped to create an overlapping portion.

[0016] In the above-described method for manufacturing a resin molded product, in the modeling step, the resin material may be discharged while continuously moving a nozzle of a model manufacturing device in the stacking direction.

[0017] In the above-described method for manufacturing a resin object, in the modeling step, a resin material may be sequentially laminated along a circumference of the rough object.

[0018] In the above-described method for producing a resin object, the removing step may include cutting a surface of the rough object to create a cut surface.

[0019] In the above-mentioned method for producing a resin molded object, the unnecessary portion may be a lamination mark.

[0020] In the above-mentioned method for producing a resin molded article, the resin molded article may be a resin block for machining.

[0021] In the above-mentioned method for producing a resin shaped object, the resin shaped object may be a resin block for cutting processing.

[0022] In the above-mentioned method for producing a resin shaped object, the resin shaped object may be any one of a rectangular parallelepiped, a cube, a cylinder, a sphere, a pyramid, and a cone.

[0023] In the above-described method for producing a resin shaped object, the resin shaped object may be cylindrical. Effect of the Invention

[0024] According to the embodiments of the present invention, it is possible to easily manufacture a resin molded object of good quality and of desired dimensions. [Brief description of the drawings]

[0025] [Figure 1] 1 is a front view showing a schematic diagram of a fused deposition model 3D printer, which is a model manufacturing apparatus used in a resin model manufacturing method according to one embodiment of the present invention. FIG. [Diagram 2] 1A is an oblique view showing an example of a rough object formed by the object manufacturing apparatus of the above-mentioned resin object manufacturing method, and FIG. 1B is an oblique view showing an example of a resin object produced by subjecting the rough object of (a) to a removal process. [Diagram 3] FIG. 2 is a plan view showing an example of 3D printing data of a concentric ring shape in the modeling step of the resin object manufacturing method. [Figure 4] FIG. 4 is a plan view showing an example of setting a reference line for configuring a scanning path of a nozzle of a 3D printer in the 3D modeling data of FIG. [Diagram 5] 5A is a plan view showing one setting example of a scanning path of a nozzle of a 3D printer in the 3D modeling data of FIG. 4, and FIG. 5B is a plan view showing another setting example. [Figure 6] 5A is a plan view showing an example of a layer formed based on the 3D printing data of FIGS. 3 and 4, FIG. 5B is a cross-sectional view of FIG. 5A, and FIG. 5C is an enlarged view of a portion of FIG. 5B. [Figure 7] FIG. 6 is a cross-sectional view of a stack of layers from FIG. 5. [Figure 8] 2(a) is a cross-sectional view showing an example of the rough object of FIG. 2(b), and (b) is an enlarged view of a part of (a). [Figure 9] (a) is a photograph showing an example of a rough object made by the resin object manufacturing device of the above-mentioned resin object manufacturing method, (b) is a photograph showing an example of a resin object made by subjecting the rough object of (a) to a removal process, and (c) is a photograph showing an example of a resin object made by further advancing the removal process from (b). [Figure 10]FIG. 1A is a plan view showing another example of the setting of the scanning path of the nozzle of the 3D printer, FIG. 1B is a plan view showing yet another example of the setting of the scanning path of the nozzle of the 3D printer, and FIG. 1C is a plan view showing yet another example of the setting of the scanning path of the nozzle of the 3D printer. [Figure 11] FIG. 4A is a plan view showing yet another example of the setting of the scanning path of the nozzle of the 3D printer, and FIG. 4B is a plan view showing yet another example of the setting of the scanning path of the nozzle of the 3D printer. [Figure 12] 11(a) is a photograph showing an example of a rough object formed by the resin object manufacturing device of the above-mentioned resin object manufacturing method based on the scanning path of Figure 11(b), and (b) is a photograph showing an example of a resin object produced by subjecting the rough object of (a) to a removal process. [Figure 13] FIG. 11 is a plan view showing yet another example of setting the scanning path of the nozzle of the 3D printer. [Figure 14] 14 is a photograph showing an example of a rough object formed by the resin object manufacturing apparatus according to the above-mentioned resin object manufacturing method, based on the scanning path shown in FIG. 13. [Figure 15] FIG. 4A is a plan view showing yet another example of the setting of the scanning path of the nozzle of the 3D printer, and FIG. 4B is a plan view showing yet another example of the setting of the scanning path of the nozzle of the 3D printer. [Figure 16] FIG. 11 is a plan view showing yet another example of setting the scanning path of the nozzle of the 3D printer. [Figure 17] 17 is a photograph showing an example of a resin object manufactured by the resin object manufacturing device of the resin object manufacturing method based on the scanning path of FIG. 16. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] An embodiment of the present invention will be described with reference to the drawings.

[0027] In FIG. 1, reference numeral 1 denotes a fused deposition modeling 3D printer, which is a device for manufacturing objects. This fused deposition modeling 3D printer (hereinafter sometimes simply referred to as "3D printer 1") is a modeling machine for manufacturing three-dimensional resin objects W by sequentially layering resin material, which is a modeling material that has been melted (dissolved) by heat, one layer at a time based on 3D modeling data.

[0028] The resin material used in the 3D printer 1 is a thermoplastic resin, and may be a general-purpose plastic, an engineering plastic, a super engineering plastic, a reinforced resin, a recycled plastic, a biomass plastic, a biodegradable plastic, or the like. More specifically, for example, PVC, POM, PBAT, AAS, PS, PLA, PBS, PE, PLA with plant fiber, PBS with plant fiber, ABS, ABS with glass fiber, ABS with carbon fiber, PP, PP with glass fiber, PLA with basalt fiber, ABS with basalt fiber, PP with basalt fiber, PC with basalt fiber, PE with basalt fiber, PVC PP with carbon fiber, PC, PC with glass fiber, PC·ABS, ASA, TPE, TPU, cellulose acetate, PA, PETG, or the like. The resin material may be in any shape, such as filament or powder, but is preferably in the form of pellets. In addition, the 3D printer 1 may be, for example, a single nozzle head type, and only one type of resin may be used for modeling, and a resin (such as a water-soluble resin) dedicated to support is not required.

[0029] The 3D printer 1 includes, for example, a box-shaped main body 3 having a modeling chamber 2 inside, a modeling head 4 that is movable in the X-axis direction (horizontal, i.e., left-right direction) and the Z-axis direction (up-down, i.e., height direction) within the modeling chamber 2, and a modeling table 5 that is movable in the Y-axis direction (horizontal, i.e., front-back direction) within the modeling chamber 2.

[0030] Since the modeling head 4 can move in the X-axis and Z-axis directions and the modeling table 5 can move in the Y-axis direction, the modeling head 4 moves in three dimensions relative to the modeling table 5 (as will be described later, the 3D printer 1 is not limited to the configuration shown in Figure 1, and it is sufficient that the modeling head 4 moves in at least three dimensions relative to the modeling table 5).

[0031] The 3D printer 1 also includes a first drive unit 6 that moves the modeling head 4 in the X-axis direction and Z-axis direction within the modeling chamber 2, a second drive unit 7 that moves the modeling table 5 in the Y-axis direction within the modeling chamber 2, and a control unit 8 that controls both drive units 6, 7, etc. based on 3D modeling data such as STL data.

[0032] Then, based on the control by the control unit 8, the modeling head 4 moves in three dimensions relative to the modeling table 5, while resin (molten resin) is ejected from the nozzle 11 of the moving modeling head 4, and as the ejected resin hardens and solidifies, the resin is layered on the modeling table 5 to form a three-dimensional rough model W1 of the desired shape.

[0033] The rough object W1 is used to finally manufacture the target resin object W. In other words, after the rough object W1 is once molded by the 3D printer 1, unnecessary parts of the rough object W1 are removed to obtain the target resin object W.

[0034] Here, the modeling head 4 of the single-nozzle head fused deposition modeling 3D printer 1 is, for example, of a molten resin extrusion type, and has a single nozzle 11 that ejects melted resin from an outlet using heat from a heating means (not shown) within the modeling head 4.

[0035] That is, the resin that has been heated and melted by a heating means such as a heater (not shown) is extruded by an extrusion means (not shown) such as a gear inside the modeling head 4, and is discharged (exhausted) from the outlet of one nozzle 11 for discharging the resin material in the direction of the central axis of the outlet, for example, downward. Note that the heating means and the extrusion means may be provided outside the modeling head 4, rather than inside the modeling head 4.

[0036] Next, a method for manufacturing a resin model using the above-described fused deposition modeling 3D printer 1 will be described, in which the three-dimensional resin model W shown in FIG. 2(b) is manufactured, for example.

[0037] The resin object W is a resin block for machining, particularly for cutting, and in this embodiment has a simple (primitive) shape, such as a rectangular parallelepiped, cube, column (cylinder, polygonal column), tube (cylinder, polygonal tube), cone (circular cone, polygonal pyramid), truncated cone (frustum cone, truncated polygonal pyramid), sphere, etc. In the example shown in Fig. 2(b), the resin object W is a thin plate-like rectangular parallelepiped that is square in a plan view.

[0038] The resin molded object W has a lower surface 15 which is a cut surface, an upper surface 16 which is a cut surface, and a side surface 17 which is a cut surface. The lower surface 15, the upper surface 16, and the side surface 17 are preferably formed as smooth surfaces with substantially no irregularities from a macroscopic perspective, but considering that they are used in machining, it is not necessary for all surfaces to be smooth, and the degree of smoothness may be such that it does not interfere with the machining itself or the finish after machining. For example, when the resin molded object W is a rectangular parallelepiped, at least the lower surface 15, the upper surface 16, and each side surface 17 are each formed in a flat shape. Also, when the resin molded object W is a column, a cylinder, a cone, or the like, the side surface 17 is formed in a cylindrical or spherical shape.

[0039] The resin molded object W is solid at least in the height direction (thickness direction). That is, the resin material is densely connected from the lower surface 15 to the upper surface 16 of the resin molded object W. In this embodiment, the resin raw material is densely connected in the planar directions (XY axis directions) and the height direction (Z axis direction) to form a solid object, and molding defects such as cavities do not basically occur within the thickness. Note that "solid" means that there is basically no cavity within the thickness, and is not intended to exclude shapes that have gaps or cavities in their external shapes, such as a cylindrical shape or a shape with a hole.

[0040] The rough object W1 for producing this resin object W is shaped to have dimensions and a shape that can contain the desired resin object W. If the rough object W1 is shaped to have dimensions that are just slightly larger than the dimensions of the resin object W plus a small amount of removal allowance, that is, dimensions that are slightly larger than the resin object W, it is possible to reduce the processing time required to remove the unnecessary parts of the rough object W1 and process it into the resin object W, and also to reduce the generation of unnecessary removal waste. On the other hand, the rough object W1 is formed to be denser (solid) toward the center due to thermal contraction of the resin material, so the larger the removal allowance, that is, the larger the rough object W is shaped relative to the resin object W, the better the quality of the resin object W. Therefore, it is preferable to appropriately select the thickness of the removal allowance for the unnecessary parts according to the quality and cost of the resin object W for the dimensions and shape of the rough object W1.

[0041] Then, a 3D printer 1 (Figure 1) is used to stack layers LY of resin material R to form a rough molded object W1 (molding process).

[0042] In this modeling process, the layer LY is formed by, for example, discharging the resin material R from the nozzle 11 of the 3D printer 1 along a predetermined scanning path (scanning line) L. The scanning path L may be set arbitrarily as long as the layer LY can be filled with the resin material R without gaps. For example, in the case of manufacturing a resin modeled object W that is a rectangular parallelepiped with a square shape in a planar view, in the example shown in FIG. 3, the square SC that follows the outer shape of the rough modeled object W1 in a planar view is designed based on 3D modeling data of a concentric ring in which a square SC is offset toward the center at a predetermined pitch p1. Note that the term "concentric ring" refers to a state in which multiple similar shapes that share a center are gathered together, and includes oval shapes such as circles, ellipses, and ovals, squares, polygons, etc., depending on the outer shape and shape of the resin modeled object W. In addition, although the case where the outer shape in a planar view is a square SC has been described, the outer shape in a planar view can be arbitrarily changed in size or tilted in the X-axis and / or Y-axis directions, and therefore it is also possible to deal with cases where the outer shape in a planar view is a rectangle, parallelogram, etc.

[0043] The pitch p1 may be set arbitrarily according to the type and grade of the resin material R as long as the resin materials R of the adjacent rings are connected to each other, that is, the resin materials R discharged from the nozzle 11 overlap each other due to flow, weight, pressure, and the like, but may be set to, for example, equal to or less than the opening width of the nozzle 11 of the 3D printer 1. In this embodiment, the nozzle 11 has a circular discharge port, and the opening diameter (opening diameter of the nozzle 11) which is the opening width is 0.2 mm to 10.0 mm, preferably 0.2 mm to 2.0 mm. In this embodiment, for example, an example is shown in which the nozzle 11 has a circular discharge port, and the opening diameter (opening diameter of the nozzle 11) is 0.2 mm to 10.0 mm, preferably 0.2 mm to 2.0 mm. In this embodiment, an example is shown in which the pitch p1 is 1.6 mm, that is, the pitch p1 is a dimension less than the opening width of the nozzle 11 and greater than 1 / 2 the opening width of the nozzle 11. However, the present invention is not limited to this, and any shape and dimension may be used according to the dimensions of the rough molded object W1, the resin material R, and the discharge amount of the resin material R from the nozzle 11. Even if the pitch p1 is larger than the opening width of the discharge port of the nozzle 11, it is possible to form a layer LY in which the resin material R that has been crushed by flow, weight, and pressure after being discharged is connected without any gaps, for example, by increasing the discharge amount (discharge rate) of the resin material R from the nozzle 11. Also, for example, when the nozzle 11 has a small diameter, it is possible to form a layer LY in which the resin material R is connected without any gaps, even if the pitch p1 is slightly smaller than 1 / 2 the opening width of the nozzle 11.

[0044] Next, in the modeling process, as shown in FIG. 4, offset lines OL serving as reference lines between the concentric rings are set at a pitch p1 for the 3D modeling data shown in FIG. 3. As shown in FIG. 5(a), each offset line OL may be a separate scanning path L, and the central axis of the nozzle 11 or the nozzle 11's outlet may be moved to the adjacent scanning path L for each revolution, or as shown in FIG. 5(b), a single scanning path L may be formed by arbitrarily connecting multiple offset lines OL in a single stroke. Note that each of the separate scanning paths shown in FIG. 5(a) is preferably a single stroke. In the example shown in FIG. 5(b), the multiple offset lines OL are connected to form the scanning path L, so that the nozzle 11 moves to the adjacent offset line OL at a position where it has made one revolution around the offset line OL, and then goes around the offset line OL in the opposite direction. Therefore, the nozzle 11 moving along the scanning path L moves from the starting point PS to the end point PE in a short distance without basically crossing itself. Since the resin material R is likely to accumulate at the start point PS (end point PE), and the accumulation tends to result in large unnecessary parts formed in the rough model W1, it is preferable to set the start point PS (end point PE) at a position other than the vertices, for example, at the center of a side, in order to minimize the unnecessary parts and reduce the removal process described below. In addition, in Fig. 5(b), the lines connecting the offset lines OL are shown slightly shifted to the left and right for clarity of explanation.

[0045] Then, by sequentially discharging the resin material R while moving the nozzle 11 along the scanning path L, that is, while rotating the nozzle 11, adjacent resin materials R are formed in layers at a predetermined pitch p1 to fill the surface, as shown in Figures 6(a) to 6(c), and adjacent molten resin materials R before solidification overlap each other at adjacent parts (shown by two-dot chain lines in the figures) to form a solid planar layer LY having a predetermined cross-sectional shape in the surface direction. Note that, in the layer LY, for a part that is not filled by the scanning path L, such as the central part of the figure drawn by the scanning path L, it is preferable to fill it so as not to form a gap by, for example, increasing the amount of resin material R discharged from the nozzle 11 or moving the nozzle 11 arbitrarily separately from the scanning path L. In addition, the resin material R discharged from the nozzle 11 is actually laminated in a cross-sectionally approximately semicircular shape according to the influence of its viscosity and surface tension, but for clarity of explanation, it will be described as being laminated in a circular shape.

[0046] In the modeling process, the 3D printer 1 models a rough model W1 so as to be solid in the height direction by stacking layers LY having the same or similar cross-sectional shape at a predetermined stacking pitch p2 in the height direction while forming overlapping parts, as shown in Fig. 7. At this time, the scanning path of the nozzle 11 in each layer LY may be the same or different. For example, in the case of the scanning path L shown in Fig. 5(a) or 5(b), the end point PE of the lower layer is set as the start point PS of the upper layer, and the start point PS of the lower layer is set as the end point PE of the upper layer, and the nozzle 11 can be moved in the opposite direction in the lower layer and the upper layer, thereby efficiently moving the nozzle 11.

[0047] The layer pitch p2 may be set so as to fill the recesses caused by the lamination marks on the upper part of the lower layer LY to prevent them from remaining as cavities inside the rough model W1. In addition, the smaller the layer pitch p2 is and the closer the opening of the nozzle 11 is to the modeling table 5 or the lower layer LY, the more the resin material R is crushed and spreads, so that the layers can be layered more densely. In this embodiment, the layer pitch p2 may be smaller than the opening width of the nozzle 11 in principle, and may be set to, for example, 0.8 mm or less, for example, equal to or less than the pitch p1. That is, the layer pitch p2 in this embodiment is larger than 0 and less than 1 / 2 the opening width of the nozzle 11. Therefore, the cross-sectional shapes (resin materials) of the layers LY adjacent to each other above and below overlap each other (as shown by the two-dot chain line in the figure), and the layers are solid in the height direction. Note that the layer pitch p2 does not need to be constant for all layers LY, and may be arbitrarily changed according to the shape of the rough model W1.

[0048] 2(a), 8(a) and 8(b) show examples of a rough object W1 formed by stacking a plurality of layers LY in this way, for example, five layers. The rough object W1 has stacking marks S, which are unnecessary parts caused by the cross-sectional shape of the resin material R discharged from the nozzle 11, on the top and stacking marks S, which are unnecessary parts caused by the stacking of the cross-sectional shape of the resin material R, on the sides.

[0049] Therefore, after removing the formed rough object W1 from the modeling table 5 of the 3D printer 1, the lamination marks S on the surface of the rough object W1 are removed by a removal device, thereby forming the resin object W shown in Fig. 2(b) (removal step). For example, when a cutting device is used as the removal device for removing the lamination marks S, the rough object W1 is set in the cutting device, and a cutting tool of the cutting device is used to cut the outer part (wall) which is the surface of the rough object W1, and the cut surfaces, the lower surface 15, the upper surface 16, and the side surface 17, are formed into a flat shape. As for the cutting tool, the smoothness of the surface of the resin object W improves as the cutting portion is finer, but there is a trade-off between smoothness and processing time, so the cutting tool may be selected according to the degree of smoothness required for the resin object W.

[0050] 2 to 8, the number of layers LY is, for example, five, but by increasing the number of layers LY, it is also possible to produce a cubic rough object W1 (resin object W) as shown in the modeling examples of Figures 9(a), 9(b), and 9(c). In the modeling example shown in Figure 9(b), the removal step is performed simply to remove the stacking marks S, thereby shortening the processing time and reducing waste by reducing the number of cutting areas, while in the modeling example shown in Figure 9(c), the removal step is performed more carefully to produce a smooth resin object W.

[0051] In this way, by using the 3D printer 1 to stack the resin material R so as to make it solid and form a rough object W1, and then removing the unnecessary part of the rough object 1, the stacking marks S, to form a resin object W, a resin object W of any size can be produced using a variety of resin materials R that can be used with the 3D printer 1 without creating steps between layers, etc., so that a high-quality resin object W of the desired size can be easily produced in a simple process.

[0052] When molding a resin object with a large height (thickness) by injection molding, internal defects such as voids and cavities are inevitably likely to occur due to internal heat generation, gas, molding shrinkage, etc., whereas by using a 3D printer 1 to form a crude object W1 by stacking solid layers LY so that they are solid in the height direction, it is possible to produce a solid crude object W1 (resin object W) with a large height (thickness) and fewer internal defects such as voids and cavities, compared to injection molding a crude object (resin object).

[0053] In the modeling process, when forming each layer LY, the nozzle 11 of the model manufacturing device is moved in a single stroke while ejecting the resin material R, thereby shortening the movement distance of the nozzle 11 and improving the modeling speed of the rough model W1.

[0054] In addition, in the modeling process, by sequentially layering the resin material R along the circumference of the rough object W1, uneven distribution of the resin raw material R is less likely to occur in the rough object W1 to be manufactured, and the quality of the resin object W is improved.

[0055] Furthermore, in the modeling process, by overlapping the resin material R and creating overlapping parts, there are no gaps between the running paths for each layer LY, and the recesses in the stacking marks formed for each layer LY in the height direction are filled with the resin material R of the adjacent layer LY above it, making it less likely to be contained as a cavity in the rough object W1 (resin object W), and the rough object W1 can be modeled as a solid object.

[0056] In the case of resin blocks for cutting by extrusion molding or injection molding as in the conventional products, only resin materials suitable for each molding method can be used, and there is also a limit to the thickness, etc., whereas the resin molded object W of the present embodiment can be molded in any dimension without using a mold by removing unnecessary parts from the rough molded object W1 using the 3D printer 1, so that it can be molded in any dimension with any resin material, that is, it has high material and dimensional freedom, and can be suitably used as a resin block for high-quality machining (cutting) made of optimal dimensions (minimum required amount) including thickness and optimal material regardless of grade. In other words, since the resin molded object W can be molded in a dimensionally optimized state as a resin block for machining (cutting), it is suitable for manufacturing processed products of the desired size, shape, and material, and the amount of cutting in the machining can be minimized, resulting in an environmentally friendly molded product with little material loss. For example, by forming the resin molded object W as a rectangular parallelepiped, cube, or cylinder, it can be made into a shape that is easy to machine. In particular, in the removal process, each surface of the resin object W can be formed flat by cutting the rough object W1. Therefore, when machining (cutting) the finished resin object W, the flat surfaces can be used to firmly fix it with a holding jig, improving processing accuracy.

[0057] Therefore, the above method also makes it possible to produce a large resin object W having many ribs, such as a water meter box, which previously required a complex mold.

[0058] In addition, because the resin object W can be formed into a single block, it is possible to reduce the labor and cost and also be more environmentally friendly compared to combining multiple plate- or rod-shaped resin objects into a block shape with adhesives, bolts, etc. Moreover, because the resin object W does not have any seams due to adhesion, etc., even if a processed product of the resin object W is used in a test using a fluid such as a liquid, the safety factor related to the strength and watertightness of the resin object W can be calculated with high accuracy.

[0059] By using a fused deposition model 3D printer 1, particularly a pellet-type 3D printer 1, it becomes possible to use a wide variety of commonly available pellet-shaped thermoplastic resins (which may be recycled pellet materials, etc.) that are inexpensive to obtain as the resin material R, and the resin molded object W can be suitably used as a resin block for machining, particularly cutting.

[0060] Since the resin object W can be made from any material, it is possible to combine multiple objects by gluing, ultrasonic welding, vibration welding, etc. to create a single larger resin object (resin block), just like conventional general resin objects.

[0061] In the above embodiment, the scanning path L of the nozzle 11 of the 3D printer 1 may be set arbitrarily as long as the layer LY can be filled with the resin material.

[0062] For example, as shown in FIG. 10(a), the scanning path L may be set in a zigzag shape. In this example, the zigzag direction of the scanning path L is a broken line consisting of components parallel or approximately parallel to the X-axis direction and the Y-axis direction. In this case, the same scanning path L may be used for each layer LY, but by setting the end point PE of the scanning path L of one layer LY as the start point of the scanning path L of another layer LY stacked on that layer LY, the moving distance of the nozzle 11 can be reduced and the modeling speed of the rough model W1 can be further improved, and by making these scanning paths L, for example, cross or cross each other at right angles, the inside of the rough model W1 can be efficiently made solid. In this case, the finer the zigzag pattern, the more voids can be suppressed from occurring inside the rough model W1.

[0063] Furthermore, the zigzag direction of the scanning path L may be inclined with respect to the X-axis direction and the Y-axis direction, as in the example shown in FIG. 10(b).

[0064] Furthermore, as shown in FIG. 10(c), the nozzle 11 may be moved along an arbitrary scanning path, such as a random one, that fills in the area except for the outer portion, and then the scanning path L may be set to form an outer portion surrounding the outside of the area along a circumference, or the order may be reversed so that after the outer portion surrounding the outside is formed, the inside of the outer portion is filled in by an arbitrary scanning path L, such as a random one.

[0065] In addition, in FIG. 10(a) to FIG. 10(c), examples of scanning paths of other layers LY to be stacked are indicated by two-dot chain lines.

[0066] Furthermore, in order to further reduce the amount of cutting (material loss) in the removal process, that is, the stacking marks S, a scanning path L may be set that sharpens the vertices of the rough object W1 so that the operation of the nozzle 11 in the modeling process is seamless and unlikely to stop at corners or vertices. In other words, the operation of the nozzle 11 is smoothed to reduce accumulations of the resin raw material R (resin accumulations) caused by stagnation of the nozzle 11, and the outer shape of the rough object W1 is brought closer to the outer shape of the resin object W, resulting in a model with fewer unnecessary parts.

[0067] For example, as shown in FIG. 11(a), the scanning path L is set as a broken line consisting of straight lines along the X-axis direction and the Y-axis direction, and a line that winds in a lightning pattern (angular spiral shape). The pitch of the lines of the scanning path L may be equal to or smaller than the diameter dimension of the nozzle 11, but the gap is set to a degree that can be filled by the close contact of the resin raw material R discharged from the nozzle 11. The scanning direction of the scanning path L may be from the outside to the inside, or from the inside to the outside. In the illustrated example, for example, the upper right end point in the figure is set as the starting point PS, and the scanning path L is set so as to gradually wind inward in a clockwise direction. This scanning path L is set as a broken line with equal or approximately equal intervals.

[0068] Preferably, the scanning path L is set to have a closed curve shape as seen from the stacking direction as shown in FIG. 11(b) based on the example shown in FIG. 11(a). That is, the scanning path L is configured so that the starting point PS and the end point PE coincide as seen from the stacking direction. In this case, the scanning path L has a shape in which the end points of a double shape consisting of a lightning-bolt-shaped offset line offset on both sides of the lightning bolt shown in FIG. 11(a) are connected. Therefore, this scanning path L has a one-stroke shape in which the starting point PS and the end point PE coincide as seen from the stacking direction.

[0069] More preferably, in the example shown in FIG. 11(b), the scanning path L is a single stroke along the stacking direction, which in this embodiment also includes the Z-axis direction. That is, the scanning path L is a spiral extending in the stacking direction. Therefore, the 3D printer 1 ejects and stacks the resin material R while continuously moving the nozzle 11 in the stacking direction at a predetermined speed. The speed at which the nozzle 11 is moved in the stacking direction is set, for example, according to the type of resin material R and the size of the resin molded object W. This speed is basically constant, but may be partially different. Then, in the modeling process, the 3D printer 1 models a rough molded object W1 so as to be solid by stacking the resin raw material R while moving in the X-axis direction, Y-axis direction, and Z-axis direction along the scanning path L shown in FIG. 11(b). An example of the rough molded object W1 based on the scanning path L shown in FIG. 11(b) is shown in FIG. 12(a), and an example of the resin molded object W manufactured by subjecting the rough molded object W to a removal process is shown in FIG. 12(b). In FIG. 12, for example, a pellet type 3D printer 1 is used, and a colored thermoplastic resin (for example, ABS or the like) is used as the resin raw material R.

[0070] In this way, by forming the scanning path L into a lightning bolt shape, the vertices of the rough object W1 are sharply angled, which not only reduces the amount of unnecessary parts to be removed in the removal process, i.e., the amount of cutting, but also because the nozzle 11 moves in a straight line over a short distance, the timing at which the resin raw material R is discharged on one line in the scanning path L is close to the timing at which the resin raw material R is discharged on the adjacent line, and adjacent resin raw material R adhere to each other in a molten state, so that the resin raw material R is easily welded to each other even at a low discharge rate of the resin raw material R, and further, if the discharge rate is increased, defects such as voids and cavities inside are less likely to occur, resulting in a good finish of the rough object W1 and the resin object W.

[0071] Compared to the example shown in Figure 5(b), the lightning-bolt-shaped scanning path L has fewer corners for the same area, which simplifies and shortens the movement path of the nozzle 11, resulting in better finishes for the rough object W1 and the resin object W.

[0072] In addition, by discharging and stacking the resin material R while continuously moving the nozzle 11 in the stacking direction, the nozzle 11 is constantly moving, and the resin raw material R is less likely to accumulate, and unevenness on the sides of the rough object W1, i.e., stacking marks S, is suppressed. In addition, the discharge rate is reduced and the rough object W1 can be formed with less resin raw material R. This reduces the amount of cutting required to create the lightning-like shape, and reduces material loss, making it possible to manufacture an environmentally friendly and low-cost resin object W. It is also possible to reduce the screw rotation speed to reduce the discharge amount and the discharge rate. For example, in the case of the example shown in FIG. 12, it was found that even if the screw rotation speed was reduced and the discharge rate was reduced to 95%, the laminated resin raw material R adhered to each other and no defects such as voids or cavities occurred.

[0073] As another example, a space-filling curve (Peano curve) on an arbitrary two-dimensional plane with a finite depth, such as a Hilbert curve with a finite depth, which fills the square SC almost evenly, may be used as the scanning path L. FIG. 13 shows an example of the scanning path L using a Peano curve. In this example, the scanning path L is a closed curve shape that connects the end points of a double shape consisting of an S-shaped broken line and an inverse S-shaped broken line, which are made of straight lines along the X-axis and Y-axis directions, symmetrically or approximately symmetrically connected to each other, and offset lines that are offset on both sides of the broken line. Therefore, this scanning path L is a one-stroke shape in which the starting point PS and the end point PE coincide when viewed from the stacking direction or in a planar view. In this case, the start point PS (end point PE) may be any position, but because accumulation of the resin raw material R is likely to occur at the start point PS (end point PE), in order to reduce stacking marks S on the outer part of the rough model W1, it is preferably set at the outermost position on the scanning path L, that is, at a position away from the position forming the outer part of the rough model W1 toward the center (inner side) from the position. The pitch of the lines of the scanning path L may be greater than or less than the diameter of the nozzle 11, but the gap should be large enough to be filled by the close contact of the resin raw material R discharged from the nozzle 11.

[0074] More preferably, in the example shown in FIG. 13, the scanning path L is a single line along the stacking direction, which in this embodiment also includes the Z-axis direction, as in the example shown in FIG. 11(b). In the modeling process, the 3D printer 1 stacks the resin raw material R while moving in the X-axis direction, Y-axis direction, and Z-axis direction along the scanning path L shown in FIG. 13 to model a rough model W1 so that the rough model W1 is solid in the surface direction (planar view) and height direction. An example of modeling the rough model W1 based on the scanning path L shown in FIG. 13 is shown in FIG. 14. FIG. 14 shows an example in which, for example, a pellet-type 3D printer 1 is used as the 3D printer 1 and a colored thermoplastic resin (e.g., ABS, etc.) is used as the resin raw material R.

[0075] In this way, by forming the scanning path L into a simple broken line shape using the Peano curve, the apex of the rough object W1 is sharpened, and the frill-like layered marks S that basically protrude to both the left and right sides (X-axis direction and Y-axis direction) can be simply removed in the removal process to easily manufacture the resin object W. In particular, in the example of the scanning path L shown in FIG. 13, the turning back part is set close to the outer side of the rough object W1, so that the frill-like layered marks S caused by the accumulation of the resin raw material R caused by the turning back of the nozzle 11 can be set on the outer side of the rough object W1, and compared to the case where the turning back part is set inside the rough object W1, cavities caused by the resin accumulation are less likely to occur inside the rough object W1. In addition, for example, by taking into consideration the cutting dimensions of the frill-like layered marks S in advance, it is also possible to easily manufacture a prismatic rough object W1 having a square bottom surface by simply cutting the two sides having the frill-like layered marks S. That is, the removal process for producing a high-quality resin object W is simple and can be completed in a short time, thereby reducing the effort and cost of production. In addition, since the moving distance of the nozzle 11 is the shortest distance required to completely fill the square SC, and the length of the straight lines in the left-right direction on the scanning path L is approximately constant, bias in the resin raw material R is unlikely to occur, and the timing of discharging the resin raw material R between adjacent lines is close, making it easy for the resin raw material R to adhere to each other in a molten state, and even if the resin raw material R is discharged at a low discharge rate, the resin raw material R is likely to be welded to each other, making it less likely that defects such as voids or cavities (voids) will occur, and the finished rough object W1 and resin object W are good.

[0076] 13 formed based on the Peano curve is a more efficient scanning path with fewer corners for the same area compared to the examples shown in Figures 5(b) and 11(b), and therefore the movement path of the nozzle 11 is simplified and shortened, resulting in better finishes for the rough object W1 and the resin object W, making it the most versatile scanning path L. Moreover, in the removal step, by setting the removal direction of the layering marks S by the removal device, for example the cutting direction by the cutting device, to the direction in which the scanning path L extends, that is, the left-right direction (XY axis direction) in Figure 13, the direction of the layering marks S by the scanning path L and the direction of the cutting marks approximately coincide with each other, making it possible to make the layering marks S less noticeable when the resin object W is manufactured.

[0077] Furthermore, by discharging and stacking the resin material R while continuously moving the nozzle 11 in the stacking direction, the nozzle 11 is constantly moving, making it difficult for the resin raw material R to accumulate, suppressing unevenness on the sides and other parts of the appearance of the rough object W1, i.e., stacking marks S, and enabling the rough object W1 to be molded with less resin raw material R by reducing the discharge rate. This, together with the reduction in the amount of cutting required to create the lightning-stripe shape, makes it possible to manufacture the rough object W with less resin, reducing material loss, and enabling the manufacture of an environmentally friendly, low-cost resin object W. In the example shown in Fig. 14 above, it was found that if the discharge rate is at least 92.5% or more, the resin raw material R adheres tightly and defects such as voids and cavities do not occur.

[0078] In addition, as long as the resin object W has a size and shape that fits into the part of the crude resin object W1 excluding the unnecessary parts, it is possible to produce a resin object W that is, for example, cylindrical or conical in shape by removing the unnecessary parts from the rectangular or cubic crude resin object W through a removal process as described above, but the outer shape of the crude resin object W1 itself may be, for example, cylindrical or cylindrical.

[0079] For example, as shown in Fig. 15(a), the scanning path L may be set to be a series of concentric rings drawn in one stroke, or as shown in Fig. 15(b), the scanning path L may be set to be an (Archimedes) spiral, i.e., an equally spaced spiral curve. In the example shown in Fig. 15(b), for example, the scanning path L of each layer LY is set to be a two-dimensional Archimedes spiral, and in one layer LY, the nozzle 11 is moved in a spiral shape from the outer end or center to the center or outer end to eject the resin material R, and the end point of the scanning path L is set as the start point of the scanning path L of another layer LY to be laminated on that layer LY, and the nozzle 11 is moved to trace the same scanning path L as the one layer LY in reverse, thereby suppressing the movement distance of the nozzle 11 between layers LY. Also, in the example shown in FIG. 15(b), when a cone-shaped resin object W is to be formed, the scanning path may be a three-dimensional Archimedes' spiral, and the nozzle 11 may be moved continuously in the lamination direction while discharging and laminating the resin material. The example of the scanning path L shown in FIG. 15(b) is curved, and therefore the movement distance is relatively long compared to the examples of the scanning path L shown in FIG. 5(b) and FIG. 11(b), etc. However, the printing time of each layer LY is longer, and the temperature of the rough model W1 after modeling is completed is lower, so warping is less likely to occur. In addition, when layers are laminated in the Z direction, the temperature of the part that has been laminated and completed modeling earlier is lower, so that lamination defects (e.g., lamination collapse) due to excessive heat are less likely to occur. Therefore, when manufacturing a resin object W with a large dimension size, a resin object W of better quality can be obtained by using the rough model W1 manufactured based on the scanning path L shown in FIG. 15(b).

[0080] Therefore, when it is desired to manufacture the resin object W using a small amount of resin and reduce voids in the object W, a rough object W1 can be manufactured using a scanning path L as shown in FIG. 13 , and when it is desired to prevent warping of the resin object W, a rough object W1 can be manufactured using a scanning path L as shown in FIG. 15 , and by cutting off unnecessary parts in each case, it is possible to create a resin object W with the desired quality and shape.

[0081] In the case of Archimedes' spiral, the coefficients a, b and parameter t are used to express Xt=a·t·cost, Yt=b·t·sint and Zt=t, and because the formulas are simple, it is possible to easily manufacture a rough object W1 with an elliptical shape or the like by setting, for example, the coefficient a and the coefficient b to different values ​​for Xt, Yt and Zt. By using a three-dimensional Archimedes' spiral scanning path, it is possible to reduce unnecessary parts to be removed, particularly when obtaining a resin object W from a conical rough object W1.

[0082] Furthermore, when manufacturing a resin object W having a circular bottom shape, such as a cylindrical shape, by setting a square-shaped scanning path L with this circle as the inscribed circle to form a rough object W1, it is possible to further reduce the amount of unnecessary parts that need to be removed when obtaining the resin object W.

[0083] Furthermore, by forming the scanning path L shown in Figures 5(b), 15(a), 15(b), etc. into a closed curve, it becomes possible to eject and stack the resin material R while continuously moving the nozzle 11 in the stacking direction.

[0084] Furthermore, when the scanning path L is a closed curve, for example, by setting the lines close to each other, it is possible to produce a wall portion or the like in the rough object W1, i.e., the resin object W, that is wider, i.e., thicker, than the diameter dimension of the nozzle 11. Therefore, it is possible to produce a resin object W with a thickness that does not depend on the diameter dimension of the nozzle 11 by setting the scanning path L, without having to replace the nozzle 11 every time, which is time-consuming. Fig. 16 shows an example of the scanning path L for forming a cylindrical, for example, hexagonal cylindrical, rough object W1. In this example, the scanning path L is a closed curve, and the portion corresponding to the outer portion of the rough object W1 is multiplexed, so that the thickness of the outer portion can be approximately multiplied by the diameter dimension of the nozzle 11, approximately doubled in this embodiment. In addition, in the case of the scanning path L for forming a cylindrical rough object W1, if the scanning path L is formed in a closed curve, a connection part is inevitably generated at the part where the multiple lines are connected, and if this connection part is exposed to the outside, the trace of the connection part will remain on the outside even if the stacking trace S is removed. Therefore, the rough object W1 is manufactured by setting a protruding part 18 that covers the connection part from the outside, and by setting a start point PS (end point PE) on the protruding part 18, for example, and removing the outer part of the protruding part 18 from the position shown by the two-dot chain line IL in the figure as an unnecessary part by cutting or the like in the removal process, the connection part is not directly exposed to the outside, and the appearance can be maintained in a good condition. An example of a resin object W molded based on the scanning path L shown in FIG. 16 is shown in FIG. 17. This resin object W is, for example, a lampshade, and has a shape twisted in the circumferential direction by gradually changing the angle of the scanning path L in the stacking direction. In this way, even if the scanning path L of each layer has the same pattern, a rough object W1 (resin object W) with a complex shape can be manufactured by changing the angle in the circumferential direction in the stacking direction. The lamination marks appearing on the outer side may be removed by polishing and / or cutting as necessary in the removal step.

[0085] Furthermore, the scanning path patterns of each layer do not have to be the same or similar. For example, the above-mentioned scanning path patterns may be arbitrarily combined with different patterns for each layer.

[0086] Furthermore, the molded object manufacturing device is not limited to a single nozzle head type, but may be a dual nozzle head type (multi-nozzle head type). In particular, in the case of a type having multiple nozzles that can be moved independently in the X-axis direction and the Y-axis direction, for example, by using different resin materials for the rough molded object W1 (resin molded object W) for each nozzle, it is possible to mold a more multifunctional resin molded object W. For example, by using a resin material with a high material cost only for the necessary parts and using a resin material with a low material cost for the remaining parts, it is possible to reduce the manufacturing cost. As an example, by forming the outer part (surface part) of the rough molded object W1 (resin molded object W) from a resin material such as ASA that has good weather resistance and forming the inner part from a resin material such as ABS that is less expensive, it is possible to inexpensively manufacture a resin molded object W with excellent weather resistance without applying a coating after manufacturing the resin molded object W. In addition, even if the same resin material is used, it is also possible to use different colors or grades for each nozzle to mold a resin molded object W with partially different colors or physical properties. Furthermore, it is also possible to form the resin object W by combining resin raw materials that are not compatible with each other.

[0087] In 3D modeling, it is possible to manufacture a resin model W with a thickness that does not depend on the diameter of the nozzle 11 by setting the scanning path L and drawing in one stroke, without using the commonly used techniques of stacking raster (infill) or contour (wall) or increasing the discharge amount. Note that the stacking method is not limited to this, and any method can be used as long as the resins melt and adhere to each other.

[0088] Furthermore, the object manufacturing apparatus is not limited to a configuration in which a modeling head (discharging means) having a nozzle for discharging resin material is movable in the X-axis and Z-axis directions and the modeling table is movable in the Y-axis direction, but may be configured so that the modeling head is movable in at least three dimensions relative to the modeling table, for example, a configuration in which the modeling head is movable in the X-axis and Y-axis directions and the modeling table is movable in the Z-axis direction, or a configuration in which the modeling head is attached to the tip of a robot arm (for example, the robot arm of a six-axis robot is preferable) and is movable in any direction including the three directions of the X-axis, Y-axis, and Z-axis directions.

[0089] For example, the modeling table 5 may be configured to be movable / rotatable along the X-axis, Y-axis, and Z-axis. The modeling table 5 may be configured in such a manner that at least one of the three axes is selected.

[0090] In addition, in the case of fractal figures (such as Hilbert curves) that fill three-dimensional space with a single stroke, modeling efficiency is improved, especially in the case of 8-axis or 9-axis modeling, because the nozzle can be moved relatively over the shortest distance without interference and modeling can be done smoothly. [Explanation of symbols]

[0091] 1. 3D printers are devices for manufacturing objects 11 Nozzle 15 Upper surface which is the cutting surface 16 Lower surface which is the cutting surface 17 Side surface that is a cutting surface LY layer R Resin material S: Unnecessary layer marks W Resin Model W1 Roughly shaped object

Claims

1. A method for manufacturing a three-dimensional resin model, comprising the steps of: a modeling step of laminating resin material using a model manufacturing device to form a rough model having a plurality of layers; a removing step of removing unnecessary parts of the crude object to form a resin object, In the modeling step, in at least one layer among the plurality of layers, a nozzle of the object manufacturing device is moved in a single stroke from a start point to an end point, while discharging a resin material from the nozzle; The start point and the end point in the at least one layer are set at positions away from a position forming an outer portion of the rough shape in order to reduce the unnecessary portion of the outer portion of the rough shape. A method for producing a resin molded object, comprising:

2. In the modeling process, the nozzle of the modeling device is moved along a closed curve whose end points are connected, while discharging the resin material. The method for producing a resin molded product according to claim 1 .

3. In the modeling process, the nozzle of the modeling device is moved in a single stroke with the start and end points coinciding when viewed from above or in the stacking direction, while discharging the resin material. The method for producing a resin molded product according to claim 2 .

4. In the modeling process, the nozzle of the modeling device is moved continuously in the layering direction while discharging the resin material.

4. The method for producing a resin molded product according to claim 1,

5. In the removal process, the surface of the rough molded object is cut to create a cut surface.

4. The method for producing a resin molded product according to claim 1,

6. The unnecessary parts are stacking marks.

4. The method for producing a resin molded product according to claim 1,

7. The lamination marks are resin pools that occur when the nozzle bends back. The method for producing a resin molded product according to claim 6 .

8. The lamination marks are irregularities on the sides of the rough molded object. The method for producing a resin molded product according to claim 6 .

9. Resin objects are resin blocks for machining.

4. The method for producing a resin molded product according to claim 1,

10. The removing step is performed on the rough object removed from the modeling table of the model manufacturing device.

4. The method for producing a resin molded product according to claim 1,

11. The resin model is a rectangular prism, cube, cylinder, sphere, pyramid, or cone.

4. The method for producing a resin molded product according to claim 1,

12. The resin molded object is cylindrical.

4. The method for producing a resin molded product according to claim 1,

Images