JP2012176508A - Method of manufacturing thick-walled molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a thick-walled molded article having sufficiently good mechanical properties and an excellent appearance.SOLUTION: There is provided the method of manufacturing a thick-walled molded article which manufactures, by injection molding of injecting a molten predetermined synthetic resin P into a molding die 11, a molded article 1 with a thickness of a predetermined dimension or more, the molded article 1 being composed of a plurality of layers laminated to each other. The method of manufacturing the thick-walled molded article includes: a primary molding process of molding, by injection molding, a primary molded layer 2 with a lamination surface 2a on which other layer is to be laminated, the lamination surface 2a being protrudingly formed with a plurality of ribs 4 extending along the surface 2a; and a secondary molding process of molding, by injection molding, a secondary molded layer 3 in such a manner that the secondary molded layer 3 is laminated on the lamination surface 2a of the primary molded layer 2. Here, in the primary molding process, the primary molded layer 2 is molded in such a manner that a tapered surface 4a inclining at an angle within a predetermined angle range relative to the direction of laminating the secondary molded layer 3 on the primary molded layer 2, is formed on at least one of both sides in a direction of a width of the each rib 4, of the each rib 4.

Description

  The present invention relates to a method for manufacturing a thick-walled molded article, which is used as a part in various industrial products and the like, and is formed by injection molding of a synthetic resin molded article having a thickness of a predetermined dimension or more.

  In recent years, synthetic resin molded products have been used for various parts of products in order to reduce the weight and cost of products in various industrial fields. Further, as such a molded product, there is an increasing demand for a thick molded product having a relatively thick dimension (for example, 10 mm or more). As a method for producing such a thick molded product, injection molding is used in which a molten synthetic resin is injected into a mold having the same cavity as the outer shape of the thick molded product. However, in the injection molding in which the synthetic resin melted in the mold is molded by one injection, the inside of the molded product is hard to be hardened compared to the outer surface side at the time of cooling after the injection, and the molded product is placed inside the molded product. Voids may occur or sink marks may occur on the outer surface of the molded product. When such molding defects occur, a molded product having sufficient strength and good appearance cannot be obtained. Therefore, Patent Document 1 discloses a method for manufacturing a thick molded product by performing injection in a plurality of times.

  In this manufacturing method, a thick molded product is manufactured by laminating a plurality of molded products having relatively thin thicknesses that do not cause voids or sink marks. Specifically, first, by performing the first injection molding in a state where the insert is detachably mounted in the movable mold, the elastic strain is applied while suppressing the thermal shrinkage of the molded product by the insert. At the same time, a first-layer molded product is molded in a preheated state. Next, the first-layer molded product is removed from the movable mold together with the insert, and is attached together with the insert in another movable mold. Then, the second-layer molded product is molded so as to be laminated on the first-layer molded product by performing the second injection molding on the surface opposite to the nesting of the first-layer molded product. Thereby, the junction part of a 1st layer molded product and a 2nd layer molded product fuse | melts, and the thick molded product in which both molded products were mutually laminated | stacked is obtained.

JP 2001-47465 A

  However, in the above manufacturing method, since the surface opposite to the nesting of the first-layer molded product, that is, the laminated surface to be laminated with the second-layer molded product is flat, the first-layer molded product and the second-layer molded product The bonding strength of the steel tends to be insufficient. In this case, the mechanical properties such as tensile and strength of the thick molded product cannot be sufficiently obtained, and the joint portion between the first molded product and the second molded product breaks due to the long-term use of the thick molded product. There is also a fear. In addition, prior to the second injection molding, the first-layer molded product must be once removed from the movable mold and mounted in another movable mold, resulting in poor manufacturing efficiency. In addition, the first-layer molded product is prone to molding shrinkage immediately after being molded and inserted into another mold, and as a result, the outer dimension of the first-layer molded product is the same as that of the inserted mold. If it is smaller than the inner peripheral surface, the synthetic resin flows between the outer peripheral side surface of the first-layer molded product and the inner peripheral surface of the mold during molding of the second-layer molded product. May occur. In this case, post-processing for cutting the burr after molding is required.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a method for producing a thick-walled molded product capable of obtaining sufficient mechanical properties and a good appearance.

  In order to achieve the above-mentioned object, the invention according to claim 1 is composed of a plurality of layers laminated to each other by injection molding in which a predetermined molten synthetic resin is injected into a mold, and has a thickness greater than a predetermined dimension. A method for producing a thick-walled molded article for producing a molded article having a primary molded layer having a plurality of ribs extending along a laminated surface to be laminated with another layer and projecting from the laminated surface. A first molding step for molding by injection molding, and a second molding step for molding the second molding layer by injection molding so as to be laminated on the laminated surface side of the first molding layer. In the next molding step, the first and second ribs have a tapered surface inclined at a predetermined angle range with respect to the lamination direction of the first molding layer and the second molding layer on at least one of both sides in the width direction of each rib. The next molding layer is molded.

  According to this configuration, the primary molding step includes forming the primary molding layer having a plurality of ribs extending along the lamination surface and projecting from the lamination surface, and performing the secondary molding step. A secondary molding layer is laminated on the lamination surface side of the primary molding layer. The plurality of ribs of the primary molding layer molded in the primary molding step have a predetermined angle range with respect to the lamination direction of the primary molding layer and the secondary molding layer on at least one of both sides in the width direction. Therefore, the area of the joint portion between the primary molding layer and the secondary molding layer is larger than in the case where the entire laminated surface is configured to be flat. For this reason, the fusion degree in the junction part of a primary molding layer and a secondary molding layer increases, As a result, the joint strength of both molding layers can be raised. Further, by molding the primary molding layer and the secondary molding layer with a thickness that does not cause voids or sink marks, the strength of the thick molded product can be increased and a good appearance can be obtained. it can. As described above, a thick molded article having sufficient mechanical properties and good appearance can be produced by the production method of the present invention.

  The invention according to claim 2 is the method for manufacturing a thick molded article according to claim 1, wherein the tapered surface is inclined by 10 degrees or more with respect to the stacking direction.

  According to this configuration, since the tapered surface is inclined by 10 degrees or more with respect to the stacking direction, the pressure of the injected synthetic resin is sufficiently applied to the tapered surface when the secondary molding layer is molded, thereby In addition, sufficient bonding strength on the tapered surface can be ensured.

  The invention according to claim 3 is the method for manufacturing a thick molded article according to claim 1 or 2, wherein the plurality of ribs are formed concentrically and / or radially about the center of the primary molding layer. It is characterized by being.

  According to this configuration, the plurality of ribs are uniformly formed on the entire laminated surface of the primary molding layer without unevenness. Therefore, the primary molding layer and the secondary molding layer are joined by the plurality of ribs. The parts can be fused in a balanced manner.

  According to a fourth aspect of the present invention, in the method for manufacturing a thick molded article according to any one of the first to third aspects, in the first molding step, the laminated surface of the first molded layer and / or the plurality of ribs are formed. A plurality of melting projections extending along the surface and projecting from the laminated surface and / or the surface of each rib and melted by the heat of the secondary molding layer when the secondary molding layer is molded by the secondary molding process A part is formed.

  According to this configuration, in the primary molding step, a plurality of molten convex portions extending along the surface of the primary molding layer and / or the plurality of ribs and projecting from the surfaces are molded. The These molten convex portions are melted by the heat of the secondary molding layer during the molding of the secondary molding layer in the secondary molding step, whereby the primary molding layer and the secondary molding layer The degree of fusion at the joint portion is further increased, and the joint strength of both molding layers can be further increased.

  According to a fifth aspect of the present invention, in the method for manufacturing a thick molded article according to the fourth aspect, the plurality of molten convex portions are formed concentrically and / or radially about the center portion of the primary molding layer. It is characterized by being.

  According to this configuration, the plurality of melt projections are uniformly formed on the entire laminated surface (including the surfaces of the plurality of ribs) of the primary molding layer without unevenness. The joint portion between the secondary molding layer and the secondary molding layer can be fused in a well-balanced manner.

  The invention according to claim 6 is the method for manufacturing a thick molded article according to any one of claims 1 to 5, wherein the predetermined synthetic resin includes a fibrous reinforcing material. .

  According to this configuration, since the primary molding layer and the secondary molding layer are molded using a synthetic resin including a fibrous reinforcing material as a constituent material, compared to a case where no reinforcing material is included, The strength of both molding layers can be increased, and as a result, the strength of the thick molded product itself can also be increased. In addition, for example, when a tensile load is applied to the thick molded product in the laminating direction of the primary molded layer and the secondary molded layer, shear stress acts on the taper surface of the rib, but in the vicinity of the taper surface. The fibrous reinforcing material that exists and does not extend along the tapered surface creates a resistance against a shear stress, thereby ensuring a stable joint state on the tapered surface.

  The invention according to claim 7 is the method for producing a thick molded article according to any one of claims 1 to 6, wherein the mold is clamped to each other, so that the primary molding layer and the secondary molding are performed. Each of the first and second cavities for forming the layer has a fixed mold plate and a movable mold plate, and the movable mold plate is molded in the first cavity in a state where the mold is opened. The first molding layer is configured to be movable to the second cavity corresponding position corresponding to the second cavity, and in the state where the fixed side mold plate and the movable side mold plate are clamped, as the primary molding step, By injecting a predetermined synthetic resin into the first cavity, forming the primary molding layer in the first cavity, opening the mold, and holding the molded primary molding layer on the movable side mold plate The position corresponding to the second cavity After being moved and clamped again, as a secondary molding step, a predetermined synthetic resin is injected into the second cavity so that the secondary molding layer is laminated on the primary molding layer in the second cavity. It is characterized by molding.

  According to this configuration, by using the mold having the fixed mold plate and the movable mold plate described above, first, by injecting the synthetic resin into the first cavity with both mold plates clamped, A primary molding layer is molded in one cavity (primary molding step). Next, after the mold is opened, the movable mold plate is moved to move the primary molding layer to the position corresponding to the second cavity while being held on the movable mold plate. Then, after both mold plates are clamped again, a synthetic resin is injected into the second cavity, and in this second cavity, the secondary molding layer is molded to be laminated on the primary molding layer (first Secondary molding step). As described above, a thick molded product having a two-layer structure is formed by the primary molding layer and the secondary molding layer.

  As described above, after forming the primary molding layer, the movable molding plate is moved while holding the primary molding layer to mold the secondary molding layer to be laminated on the primary molding layer. Therefore, compared with the conventional manufacturing method which transfers the 1st-layer molded product corresponded to a primary molding layer to another metal mold | die, a thick molded product can be manufactured efficiently. Also, since the secondary molding layer can be molded immediately after the molding of the primary molding layer, that is, before the molding shrinkage of the primary molding layer starts, unlike the conventional case, the secondary molding layer The synthetic resin of the molding layer does not flow between the outer peripheral side surface of the primary molding layer and the second cavity. For this reason, in a thick molded product, since an unnecessary burr | flash does not arise, the post-process which cuts a burr | flash is unnecessary and the outer peripheral side surface of a favorable external appearance can be obtained.

  The invention according to claim 8 is the method of manufacturing a thick molded article according to any one of claims 1 to 6, wherein the molds are clamped together to form two primary molding layers. Two first cavities for forming a second mold cavity and one of the second cavities for forming the secondary molding layer, the fixed side mold plate and the movable side mold plate, the movable side mold plate being opened In the state, a primary molding position for configuring the two first cavities and a secondary molding position for configuring the second cavity so that the open sides of the two first cavities face each other. It is configured to be movable between the fixed side mold plate and the movable side mold plate positioned at the primary molding position, and the two first cavities are predetermined in the first molding step. Two first cavities by injecting synthetic resin After forming the two primary molding layers and opening the mold, the movable side mold plate is moved to the secondary molding position so that the two primary molding layers are formed on the respective laminated surfaces. After facing each other and clamping again, as a secondary molding step, a predetermined synthetic resin is injected into the second cavity to perform secondary molding between the two primary molding layers that have been molded. It is characterized by forming a layer.

  According to this configuration, using the mold having the fixed mold plate and the movable mold plate, first, the fixed mold plate and the movable mold plate positioned at the primary molding position are clamped. By injecting synthetic resin into the two first cavities, two primary molding layers are molded in both first cavities (primary molding step). Next, after the mold is opened, the movable side mold plate is moved to the secondary molding position so that the two primary molding layers are opposed to each other so that the respective laminated surfaces face each other. Next, both mold plates are clamped again. Thereby, in the 2nd cavity, it will be in the state where two primary forming layers were inserted at intervals. Then, by injecting the synthetic resin into the second cavity, the secondary molding layer is molded between the two primary molding layers (secondary molding step). As described above, a thick molded article having a three-layer structure including two primary molding layers and a single secondary molding layer is molded.

  As described above, after the molding of the two primary molding layers, the movable mold plate is moved to the secondary molding position to mold the secondary molding layer to be laminated between the primary molding layers. Therefore, as in the seventh aspect, compared with the conventional manufacturing method, a thick molded product can be efficiently manufactured, and a thick molded product having an outer peripheral side surface with a good appearance can be obtained.

It is a perspective view which shows the thick molded article of the 2 layer structure manufactured by the manufacturing method by 1st Embodiment of this invention. It is a figure which shows the thick molded article of FIG. 1, (a) is a top view, (b) is sectional drawing cut | disconnected along the IIb-IIb line | wire of (a). It is a figure which shows the primary molding layer of a thick molded product, (a) is a top view, (b) is sectional drawing cut | disconnected along the IIIb-IIIb line of (a), (c) is a bottom face FIG. (A) is an enlarged view of the inside of the dashed-dotted line circle IVa in FIG. 3 (a), and (b) is an enlarged view of the inside of the dashed-dotted line circle IVb in FIG. 3 (b). It is a figure which shows the metal mold | die in the injection molding machine for manufacturing the thick molded article of FIG. 1, (a) shows a clamping state, (b) shows a mold open state. It is explanatory drawing for demonstrating in order the manufacturing procedure of the thick molded article of FIG. It is explanatory drawing following FIG. It is explanatory drawing following FIG. It is a perspective view which shows the thick molded article of the 3 layer structure manufactured by the manufacturing method by 2nd Embodiment of this invention. It is a figure which shows the thick molded article of FIG. 9, (a) is a top view, (b) is sectional drawing cut | disconnected along the Xb-Xb line | wire of (a). It is a figure which shows the metal mold | die in the injection molding machine for manufacturing the thick molded article of FIG. 9, (a) and (b) show a mold clamping state, (c) and (d) show a mold open state. It is explanatory drawing for demonstrating the manufacturing procedure of the thick molded article of FIG. 9 in order. It is explanatory drawing following FIG. It is explanatory drawing following FIG.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 and FIG. 2 show a thick molded product that is manufactured by the manufacturing method according to the first embodiment of the present invention and is used as a part in, for example, an automobile. The thick molded product 1 is manufactured by injection molding in which a predetermined molten synthetic resin is injected into a mold, and has a disk shape (for example, a relatively thick thickness of a predetermined dimension (for example, 10 mm) or more) , Diameter: 170 mm, thickness: 15 mm). More specifically, the thick molded product 1 is composed of a primary molding layer 2 that is injection-molded first and a secondary molding layer 3 that is injection-molded after molding the primary molding layer 2. It is configured in a two-layer structure that is stacked on top of each other. A through hole 1a having a relatively small diameter (for example, 10 mm) formed at the center of the thick molded product 1 is used for inserting a rod or the like when the thick molded product 1 is assembled. It is.

  FIGS. 3A and 3C show the top surface and the bottom surface of the primary molding layer 2, respectively, and FIG. 3B shows a cross section taken along line IIIb-IIIb in FIG. As shown in the figure, the primary molding layer 2 has a circular planar shape, and a plurality of ribs are formed on the upper surface (hereinafter referred to as “lamination surface 2 a”) laminated with the secondary molding layer 2. 4, 5 and 6 extend along the laminated surface 2a and project from the laminated surface 2a, while the bottom surface 2b is formed with a plurality of recesses 7 which open downward.

  As shown in FIG. 3A, the plurality of (eight in the present embodiment) ribs 4 are formed in a ring shape in plan shape with the through hole 1a at the center of the primary molding layer 2 as the center. At the same time, they are arranged concentrically at predetermined intervals in the radial direction. Further, the plurality of ribs 5 and 6 (eight in this embodiment) are formed in a linear plane shape and are arranged radially at equal angles with the through hole 1a as the center. Of the radial ribs 5 and 6, the former 5 extends over the entire area between the through hole 1 a and the outer peripheral edge of the primary molding layer 2, and the latter 6 is approximately half the length of the former 5. It is arranged on the outer side.

  Each rib 4, 5, 6 has the same cross-sectional shape. The ring-shaped rib 4 will be described as a representative. As shown in FIGS. 3B and 4B, the rib 4 protrudes from the laminated surface 2a by a predetermined length (for example, 3.5 mm), and the laminated surface 2a. The cross section when it cut | disconnects in the surface orthogonal to is formed in trapezoid shape. Further, the ribs 4 are formed on both sides in the width direction (left and right direction in FIG. 4B) so that the interval between the ribs 4 becomes narrower toward the secondary molding layer 3 side (upper side in FIG. 4B). The tapered surfaces 4a and 4a are provided. Specifically, each taper surface 4a has an inclination angle θ with respect to the stacking direction of the primary molding layer 2 and the secondary molding layer 3 (vertical direction in FIG. 4B) in an angle range of 10 degrees or more. It is inclined. The inclination angle θ is preferably 60 degrees or less.

  In addition, the primary molding layer 2 has a plurality of melting projections 8a that protrude toward the secondary molding layer 3 and are melted by the heat of the secondary molding layer 3 when the secondary molding layer 3 is molded. , 8b, 8c are formed. Specifically, as shown by a thick line in FIG. 4 (a), the melt convex portion 8a is disposed so as to extend along the upper surfaces of the ribs 4, 5, and 6, and the melt convex portion 8b is formed on the laminated surface 2a. The concentric ribs 4 and 4 adjacent to each other are arranged in a ring shape, and the melt projections 8c are arranged radially around the through hole 1a so as to extend across the plurality of concentric ribs 4. Has been. Moreover, each fusion | melting convex part 8a, 8b, 8c has a triangular cross-sectional shape, and has comparatively small predetermined width and height (for example, 0.2-0.5 mm).

  Further, as shown in FIGS. 3 (c) and 4 (b), a plurality of recesses 7 are formed on the bottom surface 2b on the opposite side of the laminated surface 2a of the primary molding layer 2, and these recesses are formed. 7 corresponds to the plurality of ribs 4 on the laminated surface 2a side and is arranged concentrically. Further, as shown in FIG. 3C, a plurality of ribs 9 are provided on the bottom surface 2 b of the primary molding layer 2 so as to extend radially across the concentric recesses 7.

  On the other hand, as shown in FIGS. 1 and 2, the secondary molding layer 3 has a circular planar shape, and an upper surface 3 a that is the surface opposite to the primary molding layer 2 is formed flat. .

  In the thick molded article 1 configured as described above, the primary molding layer 2 and the secondary molding layer 3 are composed of the same type of synthetic resin, and various synthetic resins may be employed. Is possible. Specifically, for example, PE (polyethylene), PP (polypropylene), ABS (acrylonitrile butadiene styrene copolymer), AES (acrylonitrile ethylene propylene rubber styrene copolymer), and AAS (acrylonitrile acrylic rubber styrene copolymer). Engineering such as general-purpose plastics such as modified PPE (modified polyphenylene ether), PA (polyamide), PC (polycarbonate), POM (polyacetal), PBT (polybutylene terephthalate), PET (polyethylene terephthalate), and PAI (polyamideimide) Plastics and PEI (polyetherimide), LCP (liquid crystal polymer), PEEK (polyetheretherketone), PSU (polysulfone), and PE (Polyethersulfone) can be employed as super engineering plastics such as.

  In addition, a reinforcing material such as glass fiber or carbon fiber may be added to the above synthetic resin, or various additives such as a material having thermal conductivity or conductivity, talc, or calcium carbonate may be added. Is possible.

  Next, a manufacturing method of the thick molded product 1 will be described with reference to FIGS. FIG. 5 shows a mold in an injection molding machine for producing the thick molded product 1, wherein (a) shows a clamped state and (b) shows a mold open state. As shown in the figure, the mold 11 includes a fixed-side mold plate 12 and a movable-side mold plate 13, and in the state where the molds are clamped, the primary molding layer 2 and the secondary molding plate 11. A first cavity 14 and a second cavity 15 for forming the layer 3 are formed.

  The fixed-side template 12 is supported by the fixed-side mounting plate 17 with the runner stripper plate 16 in between, and is formed at the time of forming the primary molding layer 2 and the secondary molding layer 3. In order to automatically take out the runner and sprue (hereinafter referred to as “flow path forming portion 20” together) from the mold 11, the runner stripper plate 16 can be separated from the runner stripper plate 16 by a predetermined distance. Further, the portion 12a corresponding to the first cavity 14 of the fixed-side mold plate 12 is formed in a convex shape protruding toward the movable-side mold plate 13, and the plurality of the first molding layers 2 described above are formed on the front end surface thereof. In order to mold the ribs 4, 5, 6, and the plurality of melting projections 8 a, 8 b, 8 c, a recess (not shown) having a shape complementary to them and opening to the movable side template 13 side Is formed. Further, the portion 12b corresponding to the second cavity 15 of the fixed side template 12 is formed flat. Further, the fixed side mold plate 12, the runner stripper plate 16 and the fixed side mounting plate 17 serve as inflow passages for the synthetic resin injected into the first and second cavities 14 and 15 from the two cylinders 18 and 18 of the injection device. Sprues and / or runners (hereinafter referred to as “resin channel 19” together) are formed.

  On the other hand, the movable side template 13 is supported by the movable side mounting plate 21 so as to be rotatable about the rotation shaft 22. Further, the recesses 13 a and 13 a corresponding to the first cavity 14 and the second cavity 15 of the movable side template 13 are formed in the same shape and size, and are arranged symmetrically around the rotation shaft 22.

  6 to 8 sequentially show the manufacturing procedure of the thick molded article 1. First, as shown in FIG. 6A, the fixed side mold plate 12 and the movable side mold plate 13 of the mold 11 are clamped. Thereby, the first cavity 14 and the second cavity 15 are constituted by the two mold plates 12 and 13. Next, as shown in FIG. 2B, molten synthetic resin P is injected into the first cavity 14 from the cylinder 18 of the injection device corresponding to the first cavity 14. Thus, the synthetic resin P injected from the cylinder 18 is filled into the first cavity 14 via the resin flow path 19 corresponding to the first cavity 14. After completion of the injection, as shown in FIG. 3C, the first cavity 14 and the corresponding synthetic resin P in the resin flow path 19 are cooled for a predetermined time while applying a predetermined holding pressure from the cylinder 18 side. To do. As a result, the synthetic resin P in the first cavity 14 and the resin flow path 19 is solidified, the primary molding layer 2 is molded in the first cavity 14, and the flow path molding portion 20 is molded in the resin flow path 19. Is done. In this case, the temperature of the primary molding layer 2 is cooled to a temperature slightly lower than the melting point of the synthetic resin P (for example, a temperature lower by 20 to 30 ° C. than the melting point).

  Next, as shown in FIG. 7A, the fixed side mold plate 12 and the movable side mold plate 13 of the mold 11 are opened, and the fixed side mold plate 12 is separated from the runner stripper plate 16. As a result, the primary molding layer 1 is held in the recess 13a corresponding to the first cavity 14 of the movable side mold plate 13, and the flow path molding is performed between the fixed side mold plate 12 and the runner stripper plate 16. Part 20 is removed. Next, as shown in FIG. 4B, after the movable side mold plate 13 is rotated by 180 degrees about the rotation shaft 22, the fixed side mold plate 12 and the movable side mold plate are moved as shown in FIG. The template 13 is clamped again. As a result, the primary molding layer 2 molded in the first cavity 14 moves to the second cavity 15. That is, the primary molding layer 2 is inserted into the second cavity 15.

  Next, as shown in FIG. 8A, molten synthetic resin P is injected into the first cavity 14 and the second cavity 15 from the two cylinders 18 and 18 of the injection device, respectively. Thereby, the synthetic resin P injected from both the cylinders 18 and 18 is filled in the entire first cavity 14 via the resin flow paths 19 and 19 corresponding to the first cavity 14 and the second cavity 15 respectively. The second cavity 15 in which the primary molding layer 2 is inserted is filled. After completion of the injection, the first cavity 14 and the second cavity 15 and the both resin flow paths corresponding to the first cavity 14 and the second cavity 15 while applying a predetermined holding pressure from both the cylinders 18 and 18 side as shown in FIG. The 19 and 19 synthetic resins P are cooled for a predetermined time. As a result, the first cavity 14 and the second cavity 15 and the synthetic resin P in both the resin flow paths 19 and 19 are solidified, and the first molding layer 2 and the second cavity 15 are respectively formed in the first cavity 14 and the second cavity 15. The next molding layer 3 is molded, and the channel molding parts 20 and 20 are molded in both the resin channels 19 and 19. That is, in the second cavity 15, the thick molded product 1 in which the primary molding layer 2 and the secondary molding layer 3 are laminated with each other is molded.

  Thereafter, as shown in FIG. 8C, the fixed side mold plate 12 and the movable side mold plate 13 of the mold 11 are opened again, and the fixed side mold plate 12 is separated from the runner stripper plate 16. In this case, the thick molded product 1 is taken out from the concave portion 13a of the movable side mold plate 13 corresponding to the second cavity 15 by an ejector (not shown), and both the flow passage molding portions 20, 20 are connected from both the resin flow passages 19, 19. Is taken out. Thus, the production of the thick molded product 1 is completed.

  In addition, after the mold opening shown in FIG. 8 (c) and taking out the molded product, the procedure shown in FIGS. 7 (b), (c) and FIGS. The thick molded product 1 can be manufactured continuously and efficiently. Further, various conditions of the injection molding machine when manufacturing the thick molded article 1, for example, the temperature of the cylinder 18 of the injection device, the injection speed, the pressure holding, the cooling time, the mold temperature, etc., are the types of the synthetic resin P. It is set appropriately according to

  As described above, according to the present embodiment, when the thick molded product 1 is manufactured, the primary molding layer 2 in which the plurality of ribs 4, 5, 6 are protruded from the laminated surface 2 a is injection molded, The secondary molding layer 3 is injection molded so as to be laminated on the lamination surface 2a side. Since each rib 4, 5, 6 has an inclined tapered surface 4 a on both sides in the width direction, the primary molding layer 2 and the secondary molding are compared with the case where the entire laminated surface 2 a is configured flat. The area of the joint portion of the layer 3 is increased. For this reason, the fusion degree in the junction part of the primary molding layer 2 and the secondary molding layer 3 increases, As a result, the joint strength of both the molding layers 2 and 3 can be raised. The primary molding layer 2 and the secondary molding layer 3 are molded with a thickness that does not cause voids or sink marks. Therefore, by the manufacturing method of the present embodiment, it is possible to manufacture the thick molded article 1 having sufficient mechanical characteristics and a good appearance. Also, since the secondary molding layer 3 is molded immediately after the molding of the primary molding layer 2, the synthetic resin P of the secondary molding layer 3 is different from the conventional case in that the synthetic resin P of the secondary molding layer 3 and the outer peripheral side surface of the primary molding layer 2 There is no flow between the two cavities 15. For this reason, in the thick molded article 1, since unnecessary burrs do not occur, post-processing for cutting burrs is unnecessary, and an outer peripheral side surface having a good appearance can be obtained.

  Moreover, since the taper surface 4a of each rib 4, 5, and 6 inclines in the angle range of 10 degree | times or more with respect to the lamination direction of the primary shaping | molding layer 2 and the secondary shaping | molding layer 3, At the time of molding the molding layer 3, the pressure of the injected synthetic resin P is sufficiently applied to the tapered surface 4a, whereby sufficient bonding strength on the tapered surface 4a can be ensured. In addition, the plurality of concentric ribs 4 and the plurality of radial ribs 5 and 6 are uniformly formed on the entire laminated surface 2a of the primary molding layer 2 without unevenness. The joint portions of the primary molding layer 2 and the secondary molding layer 3 according to 5 and 6 can be fused with good balance.

  Further, a plurality of melt projections 8 a, 8 b, 8 c are formed on the side of the laminated surface 2 a of the primary molding layer 2, and these melt projections 8 a, 8 b, 8 c are formed on the secondary molding layer 3. Since it is sometimes melted by the heat of the secondary molding layer 3, the degree of fusion at the joint portion between the primary molding layer 2 and the secondary molding layer 3 is further increased, and the joint strength between the molding layers 2, 3 is increased. Can be further increased. In addition, since the concentric or radial melting projections 8a, 8b, 8c are uniformly molded on the entire laminated surface 2a side of the primary molding layer 2, the above-described melting projections 8a, 8b, The joint portion between the primary molding layer 2 and the secondary molding layer 3 by 8c can be fused in a well-balanced manner.

  In addition, when a synthetic resin to which a fibrous reinforcing material such as glass fiber or carbon fiber is used as a constituent material of the thick molded article 1, the primary molding is performed as compared with the case where the reinforcing material is not included. The strength of the layer 2 and the secondary molded layer 3 can be increased, and as a result, the strength of the thick molded product 1 itself can also be increased. For example, when a tensile load is applied to the thick molded product 1 in the stacking direction of the primary molded layer 2 and the secondary molded layer 3, shear stress is applied to the tapered surfaces 4 a of the ribs 4, 5, 6. Although acting, the fibrous reinforcing material that exists in the vicinity of the tapered surface 4a and does not extend along the tapered surface 4a creates a resistance against shearing stress, thereby ensuring a stable bonding state on the tapered surface 4a. it can.

  Next, the thick molded product 31 manufactured by the manufacturing method according to the second embodiment of the present invention and the manufacturing method thereof will be described with reference to FIGS. FIGS. 9 and 10 show a thick molded product 31, and this thick molded product 31 is similar to the thick molded product 1 in the first embodiment described above. Manufactured by injection molding. As shown in both figures, the thick molded product 31 is formed into a block shape having a relatively thick thickness not less than a predetermined dimension (for example, 10 mm) and having a planar shape that is substantially rectangular, and is first injection-molded first. A molding layer 32 (primary molding layer) and a lower molding layer 33 (primary molding layer), and an intermediate molding layer 34 (secondary molding layer) formed by injection molding between the molding layers 32 and 33 after molding. And a three-layer structure laminated with each other. In addition, in the center part of this thick molded product 31, the recessed part 31a open | released upwards and a planar shape is circular is formed.

  As shown in FIG. 10B, the lower surface (hereinafter referred to as “lamination surface 32a”) laminated with the middle molding layer 34 of the upper molding layer 32 and the upper surface (hereinafter referred to as “lamination surface 32a”) of the lower molding layer 33. Like the primary molding layer 2 of the thick molded product 1 in the first embodiment described above, a plurality of ribs 35 and 36 projecting toward the middle molding layer 34 are provided on the laminated surface 33a ”, respectively. Yes. That is, these ribs 35 and 36 extend along the laminated surfaces 32a and 33a and are arranged concentrically or radially like the ribs 4, 5 and / or 6 of the primary molding layer 2 of the thick molded article 1. Has been. Further, each rib 35, 36 is formed on both sides in the width direction (left and right direction in FIG. 10B) in the same manner as the rib 4 and the like so that the interval between the ribs 35, 36 becomes narrower toward the middle molding layer 34 side. It has the taper surface which inclines in the angle range of 10 degree | times or more with respect to the lamination direction (up-down direction of FIG.10 (b)) of each layer 32-34.

  In the thick molded product 31, the height dimension of the middle molded layer 34 is set to be substantially constant due to the positional relationship between the ribs 35 of the upper molded layer 32 and the ribs 36 of the lower molded layer 33. Further, the portion corresponding to the concave portion 31a of the upper molding layer 32 is formed so as to protrude toward the middle molding layer 34 side than the other portion, while the portion corresponding to the concave portion 31a of the lower molding layer 33 is It is formed in a state of being recessed from the other portions.

  Further, when the upper molded layer 32 and the lower molded layer 33 are molded during the production of the thick molded product 31, the melt projections 8a, 8b and / or 8c of the primary molded layer 2 of the thick molded product 1 Similar melt convex portions are formed on the ribs 35 and 36 and the laminated surfaces 32a and 33a.

  In the thick molded product 31 configured as described above, the upper molded layer 32, the lower molded layer 33, and the middle molded layer 34 are formed of the same synthetic resin, and the synthetic resin is the same as the thick molded product 1 described above. It is possible to employ the various synthetic resins described above.

  Next, a method for manufacturing the thick molded article 31 will be described with reference to FIGS. FIG. 11 shows a mold in an injection molding machine for producing a thick molded product 31, wherein (a) and (b) show a clamped state, and (c) and (d) show a mold open state. ing. The mold 41 includes a fixed-side mold plate 42 and a movable-side mold plate 43, and the fixed-side mold plate 42 is immovably supported by the fixed-side mounting plate 44, while the movable-side mold plate 43 serves as a guide plate. Via the 45, it is supported by the movable side mounting plate 46 so as to be movable in the vertical direction between a first molding position and a second molding position described later. As shown in FIG. 11 (a), when the movable side mold plate 43 is located at the primary molding position, the upper molding layer 32 and the lower stage molding are in a state of being clamped with the fixed side mold plate 42. An upper cavity 47 (first cavity) and a lower cavity 48 (first cavity) for forming the layer 33 are formed. On the other hand, as shown in FIG. 11B, when the movable side mold plate 43 is located at the secondary molding position, the upper molding layer 32 and the lower molding layer are in a state of being clamped to the fixed side mold plate. An intermediate cavity 49 (second cavity) for forming the intermediate forming layer 34 is formed between 33.

  As shown in FIG. 11C, the recess 42a corresponding to the upper cavity 47 of the fixed side mold plate 42 is formed so as to open to the movable side mold plate 43 side. The portion 42b corresponding to the lower cavity 48 of the fixed-side mold plate 42 is formed in a convex shape protruding toward the movable-side mold plate 43, and the plurality of ribs 36 of the lower molding layer 33 described above are formed on the front end surface thereof. And in order to shape | mold a fusion | melting convex part, the recessed part (not shown) which has a shape complementary to them and is open | released to the movable side template 43 side is formed.

  On the other hand, the movable side mold plate 43 is guided by the actuator 50 by the guide plate 45, and the primary molding position shown in FIGS. 11 (a) and 11 (c), as shown in FIGS. 11 (b) and 11 (d). It is configured to be driven in the vertical direction between the secondary molding position. Further, the portion 43a corresponding to the upper cavity 47 of the movable side mold plate 43 has a shape complementary to the above-described ribs 35 and the melt projections of the upper molding layer 32, and has a shape complementary thereto. A recess (not shown) is formed on the fixed side mold plate 42 side. Further, the recess 43b corresponding to the lower cavity 48 of the movable side mold plate 43 is formed so as to open to the fixed side mold plate 42 side.

  Further, as shown in FIG. 11A, when the fixed side mold plate 42 and the movable side mold plate 43 are clamped in a state where the movable side mold plate 43 is located at the primary molding position, both mold plates are used. 42 and 43, sprues and runners as inflow passages of the synthetic resin P injected from the cylinder 51 of the injection device to the upper cavity 47 and the lower cavity 48 (hereinafter collectively referred to as “first resin flow path 52”). Is configured. On the other hand, as shown in FIG. 11B, when the fixed side mold plate 42 and the movable side mold plate 43 are clamped in a state where the movable side mold plate 43 is located at the secondary molding position, both mold plates are used. A sprue (hereinafter referred to as “second resin flow path 53”) as an inflow passage of the synthetic resin P injected from the cylinder 51 to the middle cavity 49 is configured in 42 and 43.

  FIGS. 12-14 has shown the manufacture procedure of the thick molded article 31 in order. First, as shown in FIG. 12A, the fixed side mold plate 42 of the mold 41 and the movable side mold plate 43 located at the primary molding position are clamped. Thus, the upper mold 47 and the lower cavity 48 are constituted by the both mold plates 42 and 43, and the first resin flow path 52 is constituted. Next, as shown in FIG. 2B, molten synthetic resin P is injected into the upper cavity 47 and the lower cavity 48 from the cylinder 51 of the injection device. Thereby, the synthetic resin P injected from the cylinder 51 is filled into the upper cavity 47 and the lower cavity 48 via the first resin flow path 52. After completion of the injection, as shown in FIG. 5C, the upper cavity 47 and the lower cavity 48 and the synthetic resin P in the first resin flow path 52 are set in a predetermined manner while applying a predetermined holding pressure from the cylinder 51 side. Cool for hours. As a result, the synthetic resin P in the upper cavity 47 and the lower cavity 48 and the first resin flow path 52 is solidified, and the upper molding layer 32 and the lower molding layer of the thick molded product 31 in the upper cavity 47 and the lower cavity 48, respectively. 33 is molded, and the first flow path molding portion 52 a is molded in the first resin flow path 52. In this case, the temperature of the upper molding layer 32 and the lower molding layer 33 is cooled to a temperature slightly lower than the melting point of the synthetic resin P (for example, a temperature lower by 20 to 30 ° C. than the melting point).

  Next, as shown in FIG. 13A, the fixed side mold plate 42 and the movable side mold plate 43 of the mold 41 are opened. In this case, the upper molding layer 32 is held in the recess 42 a corresponding to the upper cavity 47 of the fixed mold 42, while the lower molding layer 33 is formed in the recess 43 b corresponding to the lower cavity 48 of the movable mold 43. Retained. In this case, the first flow path molding part 52 a is taken out between the fixed side mold plate 42 and the movable side mold plate 43. Next, as shown in FIG. 5B, the movable mold plate 43 is driven from the primary molding position to the secondary molding position by the actuator 50 via the drive rod 50a. As a result, the lower molding layer 33 on the movable mold plate 43 side moves so as to face the upper molding layer 32 on the fixed mold plate 42 side, and the laminated surfaces 32a and 33a of the molding layers 32 and 33 face each other. Next, as shown in FIG. 3C, the fixed side mold plate 42 and the movable side mold plate 43 are clamped again. As a result, both mold plates 42 and 43 constitute the middle cavity 49 and the second resin flow path 53. In this case, in the middle cavity 49, the upper molding layer 32 and the lower molding layer 33 are inserted with a space therebetween, and the second resin flow path 53 is continuous between the molding layers 32 and 33. Become.

  Next, as shown in FIG. 14A, the molten synthetic resin P is injected into the middle cavity 49 from the cylinder 51 of the injection device. Thereby, the synthetic resin P injected from the cylinder 51 is filled between the upper molding layer 32 and the lower molding layer 33 of the middle cavity 49 through the second resin flow channel 53. After completion of the injection, the synthetic resin P in the middle cavity 49 and the second resin flow path 53 is cooled for a predetermined time while applying a predetermined holding pressure from the cylinder 51 as shown in FIG. As a result, the synthetic resin P between the upper molding layer 32 and the lower molding layer 33 is solidified in the middle cavity 49, and the middle molding layer 34 is molded between the upper molding layer 32 and the lower molding layer 33. That is, in the middle cavity 49, the thick molded product 31 in which the middle molding layer 34 is laminated between the upper molding layer 32 and the lower molding layer 33 is molded.

  After that, as shown in FIG. 14C, the fixed side mold plate 42 and the movable side mold plate 43 of the mold 41 are opened again. In this case, the thick molded product 31 is taken out from the concave portion 43 b of the movable side mold plate 43 and the flow path molding portion 53 is taken out from the second resin flow channel 53 by an ejector (not shown). Thus, the production of the thick molded product 31 is completed.

  14 (c) to 14 (c) described above after returning the movable side mold plate 43 to the lower primary molding position after the mold opening and taking out the molded product shown in FIG. 14 (c). A large number of thick molded articles 31 can be manufactured continuously and efficiently by repeating the procedure shown in FIG.

  As described above, according to the present embodiment, when the thick molded product 31 is manufactured, the upper molding layer 32 in which the plurality of ribs 35 protrude from the lamination surface 32a and the plurality of ribs 36 on the lamination surface 33a. The projecting lower molding layer 33 is injection-molded, and the upper molding layer 32 and the lower molding layer 33 are placed between the molding layers 32 and 33 in a state where the laminated surfaces 32a and 33a face each other. The middle molding layer 34 is injection molded. As a result, as in the first embodiment, the degree of fusion between the joining portion of the upper molding layer 32 and the middle molding layer 34 and the joining portion of the lower molding layer 33 and the middle molding layer 34 is increased, and the three molding layers 32, 33, The bonding strength of 34 can be increased. Therefore, the thick molded product 31 having the same effect as that of the first embodiment can be manufactured by the manufacturing method of the present embodiment.

  Note that the present invention is not limited to the first and second embodiments described above, and can be implemented in various modes. For example, in the first embodiment, the tapered surfaces 4a and 4a are provided on both sides in the width direction of the ribs 4, 5, and 6, but the tapered surfaces 4a may be provided only on one of the both sides. In the first embodiment, the concentric ribs 4 and the radial ribs 5 and 6 are provided. However, the type and arrangement of the ribs are not particularly limited. It is also possible to provide one or two, or to provide a lattice-like rib instead. Furthermore, in 1st Embodiment, although the fusion | melting convex part 8a, 8b, 8c was provided in the lamination | stacking surface 2a side of the primary shaping | molding layer 2, the primary shaping | molding layer 2 and 2nd by rib 4, 5, 6 are provided. In the case where sufficient bonding strength is obtained between the next molding layers 3, it is possible to omit the melt projections 8a, 8b, 8c. The above also applies to the ribs 35 and 36 and the melted convex portion of the second embodiment.

  In the second embodiment, after molding the molding layers on both sides of the thick molded product 31, that is, the upper molding layer 32 and the lower molding layer 33, the middle molding layer 34 is injection molded between the molding layers 32 and 33. By doing so, the thick molded article 31 having a three-layer structure is manufactured, but it may be injection-molded in order for each molding layer. In this case, for example, the movable mold plate or the fixed mold plate of the mold is configured to be slidable in a predetermined direction orthogonal to the direction of clamping and opening the mold, and the layer to be molded along the predetermined direction. Side by side cavities. By using such a mold, it is possible to produce a thick molded product having four or more layers as well as a three-layer structure.

  In the first embodiment, the primary molding layer 2 and the secondary molding layer 3 constituting the thick molded product 1 are made of the same synthetic resin, and in the second embodiment, the thick molded product 31 is formed. The upper molding layer 32, the lower molding layer 33, and the middle molding layer 34 that are formed are made of the same synthetic resin, but the present invention is not limited to this, and the molding layers are made of different types of synthetic resins. It is also possible to do.

  Moreover, the external shape of the thick molded products 1 and 31 shown by embodiment, the structure of the detail of the metal molds 11 and 41 for manufacturing them are an illustration to the last, and are suitably in the range of the meaning of this invention. Can be changed.

DESCRIPTION OF SYMBOLS 1 Thick-walled molded product 2 Primary molding layer 2a Lamination surface 3 Secondary molding layer 4 Rib 4a Tapered surface 5 Rib 6 Rib 8a Melting convex part 8b Melting convex part 8c Melting convex part 11 Mold 12 Fixed side template 13 Movable side mold plate 14 First cavity 15 Second cavity 18 Injection device cylinder 22 Rotating shaft 31 Thick molded product 32 Upper molding layer (primary molding layer)
32a Laminated surface 33 of upper molding layer Lower molding layer (primary molding layer)
33a Laminated surface 34 of lower molding layer Middle molding layer (secondary molding layer)
35 Rib 36 of Upper Molding Layer 36 Rib of Lower Molding Layer 41 Mold 42 Fixed Side Plate 43 Movable Side Plate 45 Guide Plate 47 Upper Cavity (First Cavity)
48 Lower cavity (first cavity)
49 Middle cavity (second cavity)
50 Actuator 51 Cylinder of injection device θ Inclination angle of rib P Molten synthetic resin

Claims (8)

A method for producing a thick-walled molded article, which comprises a plurality of layers laminated to each other and a molded article having a thickness of a predetermined dimension or more by injection molding in which a predetermined molten synthetic resin is injected into a mold. ,
A primary molding step of molding a primary molding layer having a plurality of ribs extending along a lamination surface to be laminated with another layer and projecting from the lamination surface by the injection molding;
A secondary molding step of molding a secondary molding layer by the injection molding so as to be laminated on the lamination surface side of the primary molding layer;
With
In the primary molding step, at least one of both sides of each rib in the width direction has a tapered surface that is inclined in a predetermined angle range with respect to the stacking direction of the primary molding layer and the secondary molding layer. Thus, the manufacturing method of the thick molded product characterized by shape | molding the said primary molding layer.   The method of manufacturing a thick molded product according to claim 1, wherein the tapered surface is inclined at least 10 degrees with respect to the stacking direction.   3. The method for manufacturing a thick molded article according to claim 1, wherein the plurality of ribs are formed concentrically and / or radially around a central portion of the primary molding layer.   In the first molding step, the first molding layer extends along the lamination surface and / or the surfaces of the plurality of ribs and protrudes from the lamination surface and / or the surfaces of the ribs. 4. A plurality of molten convex portions that are melted by the heat of the secondary molding layer are molded at the time of molding the secondary molding layer in a secondary molding step. Of manufacturing thick-walled molded article.   5. The method for manufacturing a thick molded article according to claim 4, wherein the plurality of molten convex portions are formed concentrically and / or radially around a center portion of the primary molding layer.   The method for manufacturing a thick molded article according to any one of claims 1 to 5, wherein the predetermined synthetic resin includes a fibrous reinforcing material. The mold is clamped together to form a first cavity and a second cavity for molding the primary molding layer and the secondary molding layer, respectively. Have a template,
The movable side mold plate is configured to be movable in a state where the first molding layer formed in the first cavity is moved to a second cavity corresponding position corresponding to the second cavity in a state where the mold is opened.
In the state where the fixed mold plate and the movable mold plate are clamped, as the first molding step, the first synthetic resin is injected into the first cavity, whereby the first cavity is filled with the first synthetic resin. Next molding the molding layer,
After opening the mold, the molded primary molding layer is moved to the position corresponding to the second cavity while being held in the movable side mold plate,
After the mold is clamped again, as the second molding step, the second molding layer is laminated on the first molding layer in the second cavity by injecting the predetermined synthetic resin into the second cavity. The method for producing a thick-walled molded article according to any one of claims 1 to 6, wherein the thick-walled molded article is molded as described above. The molds are clamped together to form one of two first cavities for molding the two primary molding layers and a second cavity for molding the second molding layer. Comprising a fixed-side template and a movable-side template,
When the movable side template is opened, the first molding position for configuring the two first cavities and the open side of the two first cavities face each other. It is configured to be movable between the secondary molding positions for configuring the cavity,
As the first molding step, the predetermined synthetic resin is injected into the two first cavities in a state where the fixed side template and the movable side template located at the first molding position are clamped. To form the two primary molding layers in the two first cavities,
After opening the mold, by moving the movable side mold plate to the secondary molding position, the two primary molding layers that have been molded are opposed so that the respective laminated surfaces face each other,
After the mold is clamped again, as the secondary molding step, the second synthetic layer is injected between the two primary molded layers formed by injecting the predetermined synthetic resin into the second cavity. The method for producing a thick molded article according to any one of claims 1 to 6, wherein the molded article is molded.

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