JP5613534B2 - Manufacturing method of mold for molding - Google Patents

Description

  The present invention relates to a method for producing a molding die that is used when foamed resin particles are molded into a foamed molded product and can form an uneven pattern on the surface of the foamed molded product.

  A foam molded body made of a thermoplastic resin such as polystyrene, polyethylene, polypropylene, etc. is formed by using the first and second molding dies that form a molding space that matches the shape of the target foam molded body when the mold is closed. The foamed resin particles are made by filling the foamed resin particles made of a thermoplastic resin into the space and heating the foamed resin particles in the molding space with a heating medium such as water vapor so that the foamed resin particles are foamed and fused together.

  In addition, the surface of the foamed molded product produced by foaming and fusing the foamed resin particles is formed with a tortoiseshell pattern of the foamed resin particles, so that the molding surface is made uneven to make the tortoiseshell pattern inconspicuous. Such a molding die is known. As a method of manufacturing this type of molding die, first, a metal net or punching metal is pasted on the surface of a model (for example, a wooden mold), and this model is used to have a concavo-convex pattern transferred from the metal mesh or punching metal. A method is known in which a reversal mold (for example, a sand mold) is manufactured, and further a mold for molding having a concavo-convex pattern transferred from the reversal mold is used (Patent Document 1).

  However, in the method of attaching a wire mesh to the surface of the model, the wire mesh is a knitted structure, that is, a structure formed by knitting so that the line portions constituting the mesh are vertically crossed, and therefore, between the model and the wire mesh. If a reversal mold is produced using this model, the sand will enter the gap between the model and the wire mesh and turn into the inside of the wire mesh and reverse when the model is removed. There is a problem that problems such as mold collapse occur.

  Also, with the method of attaching punching metal to the surface of the model, it is difficult to apply the punching metal along the curved surface or concave corners of the model because the punching metal is hard and not flexible. There is a problem that it can be used only for a model having a relatively simple shape without a curved surface or concave corners.

  Therefore, in order to solve such a problem, the applicant of the present invention invented the use of a net-like member made of a net-like synthetic resin sheet having a large number of net holes instead of a metal net or punching metal as the concavo-convex pattern forming member. According to this, since the mesh member has no vertical crossing between the line portions constituting the mesh like a wire mesh, the casting sand does not enter between the model and the mesh member, and is a synthetic resin sheet. Therefore, it can stick and stick so that it may follow also the surface which consists of curved surfaces (patent documents 2).

Registered Utility Model No. 3045015 JP 2006-231633 A

  However, in the method of attaching the mesh member to the surface of the model, since only the line part of the mesh member is attached to the surface of the model, the adhesion area of the mesh member to the surface of the model is small. If the model is manufactured, the mesh member may be peeled off from the surface of the model when the model is extracted.

  This invention is made | formed in view of this situation, and makes it a subject to provide the manufacturing method of the metal mold | die for a concavo-convex pattern formation member which does not peel from the surface of a model at the time of extraction of a model.

The present invention has been made in order to solve the above problems, and is a molding die for molding a foam molded article, and a concavo-convex pattern forming member is attached to the entire surface or a predetermined range of a model, For forming a reversal mold having a concavo-convex pattern transferred from a concavo-convex pattern forming member using a model, and further manufacturing a molding die having a concavo-convex pattern transferred from the reversal mold using the reversal mold the method of manufacturing a mold, the convex-concave as pattern forming member, the unevenness of the original on one side by pressing with a press plate having laid the synthetic resin sheet a smooth surface on the precursor having an uneven pattern Using the material transferred by embedding the pattern, the concavo-convex pattern forming member is attached to the surface of the model on the smooth surface opposite to the concavo-convex surface to which the concavo-convex pattern was transferred, and the inverted mold is manufactured. To make a concavo-convex pattern Enclosed in pasted model a frame of sampling the model after solidified molding sand filling the molding sand to fill the model from molding sand, characterized in Rukoto.

  According to the present invention, when a synthetic resin sheet is laid on an original plate and pressed using a press plate, one surface of the synthetic resin sheet (contact surface with the original plate) is transferred to the uneven surface of the original plate. However, the opposite surface (contact surface with the press plate) is a smooth surface as it is the synthetic resin sheet before pressing. This is used as a concavo-convex pattern forming member, the smooth surface side is attached to the surface of the model, and an inverted mold having a concavo-convex pattern transferred from the concavo-convex pattern forming member is produced using the model, and further, the inverted mold is used to A molding die having a concavo-convex pattern transferred from the reversal mold is manufactured.

  In this method, since the adhesion area of the concavo-convex pattern forming member to the surface of the model is increased, if the inverted mold is manufactured using this model, the concavo-convex pattern forming member will not be peeled off from the surface of the model when the model is removed. . Further, since the concave / convex pattern forming member is not a through hole in the concave / convex surface, casting sand does not enter between the model and the concave / convex pattern forming member, and since it is a synthetic resin sheet, it has a curved surface. It can be attached in close contact with the surface of the shaped model, and can be applied to a model having a complicated three-dimensional surface.

  Here, in the present invention, a concavo-convex pattern forming member may be obtained by cold pressing, but a thermoplastic synthetic resin sheet is used as a synthetic resin sheet and pressed while applying heat (hot pressing). It is preferable to do so. According to this, the concavo-convex pattern of the original plate can be firmly transferred to one side (one side) of the synthetic resin sheet.

  In the present invention, it is preferable that the original plate has an uneven pattern in which concave portions and convex portions are alternately aligned. The concave / convex pattern forming member is thinned by the concave portion, and the flexibility is enhanced at the portion. However, the concave / convex pattern is formed by alternately arranging the concave portion and the convex portion. Therefore, the concavo-convex pattern forming member is excellent in flexibility as a whole, so that it can be adhered and adhered to the surface of a curved model surely. Is extremely widespread.

  As described above, according to the present invention, it is possible to provide a method for manufacturing a molding die in which the concavo-convex pattern forming member does not peel from the surface of the model when the model is extracted.

Sectional drawing of the mold open state of the metal mold | die for molding which concerns on this embodiment is shown. Sectional drawing of the wooden pattern for convex dies which concerns on the embodiment is shown. Sectional drawing of the state which affixed the uneven | corrugated pattern formation member on the surface of the wooden mold for convex molds which concerns on the embodiment is shown. It is an uneven | corrugated pattern formation member which concerns on the embodiment, Comprising: (a) is a top view, (b) shows a partial expanded sectional view. Explanatory drawing of the process of pressing the uneven | corrugated pattern formation member which concerns on the embodiment is shown. Sectional drawing of the process of manufacturing the lower mold | type of the sand mold for convex dies which concerns on the embodiment is shown. Sectional drawing of the lower mold | type of the sand mold for convex dies which concerns on the embodiment is shown. Sectional drawing of the upper mold | type of the sand mold for convex dies which concerns on the embodiment is shown. Sectional drawing of the sand mold | type for convex molds concerning the embodiment is shown.

  Hereinafter, an embodiment of a method for producing a molding die according to the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, the molding die according to this embodiment includes a pair of molding dies, that is, a convex molding die (hereinafter referred to as “convex die”) 10 and a concave molding. And a metal mold 20 (hereinafter referred to as “concave mold”).

  First, when manufacturing the convex mold 10, as shown in FIG. 2, a convex mold 30 (model) 30 having a surface 31 having a shape corresponding to the convex mold 10 is prepared. The wooden mold 30 is manufactured by machining with an appropriate cutting tool or the like using wood or the like. Next, as shown in FIG. 3, a concavo-convex pattern forming member 40 is attached to the surface 31 of the wooden mold 30.

  The concavo-convex pattern forming member 40 is made of a synthetic resin sheet, and can be easily deformed along the surface 31 of the wooden mold 30 even if the wooden mold 30 has a complicated three-dimensional surface 31. Examples of the material include resins such as polyethylene, polypropylene, polyvinyl chloride, and polyester, or copolymers of these resins (for example, acrylonitrile / butadiene / styrene copolymer resin (ABS resin)). be able to. The thickness is preferably 0.1 mm or more, more preferably 0.3 mm or more, preferably 1.0 mm or less, and more preferably 0.5 mm or less.

  In addition, as shown in FIG. 4, the concavo-convex pattern forming member 40 is a concavo-convex surface in which one surface 41 is formed so that the concave portions 42 and the convex portions 43 are alternately aligned and arranged over the entire surface (however, FIG. 4A shows a concavo-convex pattern only in part), and the opposite surface (the other surface) 44 is a smooth surface. And (if necessary, the concave / convex pattern forming member 40 is cut into a shape corresponding to the surface 31 of the wooden mold 30), and the concave / convex pattern forming member 40 is placed on the other surface 44 side so that the other surface 44 is inside. To be attached to the surface 31 of the wooden mold 30.

  There are various methods of attaching, for example, a method of applying the adhesive to the surface 31 of the wooden mold 30 and / or the entire surface of the concave / convex pattern forming member 40 or an appropriate location and sticking the concave / convex pattern forming member 40, both sides Examples include a method of attaching the concavo-convex pattern forming member 40 by attaching an adhesive sheet or a double-sided adhesive tape to the entire surface 31 of the wooden mold 30 and / or the entire surface of the concavo-convex pattern forming member 40 or an appropriate place.

  Here, the concavo-convex pattern forming member 40 is formed by using a press molding machine from a synthetic resin sheet having a constant thickness with both surfaces being smooth so that one side of the synthetic resin sheet becomes an concavo-convex surface. Specifically, as shown in FIG. 5, the press molding machine includes a base A and a press plate B having a smooth surface, and a press plate B having a heat source inside, and on the base A, First, foam urethane sheet C is laid as a cushioning material, wire mesh D is laid thereon, synthetic resin sheet 40 'is laid thereon, and finally Teflon (registered trademark) sheet E is laid as a protective material. The plate B is moved to the base A side, and the synthetic resin sheet 40 ′ is pressed.

  At this time, the press plate B becomes a heat plate by an internal heat source, and this heat is transferred to the synthetic resin sheet 40 ′, and the synthetic resin sheet 40 ′ is softened. Therefore, when the synthetic resin sheet 40 ′ is pressed, the metal mesh D (for example, a 14-mesh linear 5.7 wire mesh) sinks into one surface 41 ′ of the synthetic resin sheet 40 ′, and the metal mesh D is uneven. The pattern is transferred to one surface 41 ′ of the synthetic resin sheet 40 ′, and the one surface 41 ′ becomes an uneven surface. However, since the other surface 44 'has a smooth surface of the press plate B, it is a smooth surface as it is with the synthetic resin sheet 40' before pressing.

The pressing conditions (pressing pressure, pressing temperature, pressing speed, etc.) are appropriately set according to the specifications of the target concavo-convex pattern forming member 40. However, if the pressing pressure is high or the pressing temperature is high, the convex portion of the wire mesh D reaches the other surface 44 ′ of the synthetic resin sheet 40 ′, forming a through hole, or the synthetic resin sheet 40 ′. Therefore, it is necessary to set conditions based on this point. Specifically, if the press pressure is less than 1 kgf / cm ² , the uneven pattern becomes shallow and sharpness cannot be obtained, whereas if it is greater than 10 kgf / cm ² , the synthetic resin sheet 40 ′ is broken. because fear is preferably 1 kgf / cm ² or more, more preferably at most 4 kgf / cm ² or more, preferably 10 kgf / cm ² or less, more preferably 5 kgf / cm ² or less. For the same reason, 25% hardness of the urethane foam sheet C (ILD) is, 30 N / 314 cm ² or more, more preferably at most 80 N / 314 cm ² or more, preferably 300N / 314 cm ² or less, more Preferably, it is 120 N / 314 cm ² or less.

  Moreover, in order to make the turtle shell pattern of the foamed resin particles inconspicuous on the surface of the foam molded article, the size of one concave portion 42 or the concave portion 43 in the concave / convex pattern forming member 40 is set to 0.5 mm × 0.5 mm to 5 mm. 0.0 mm × 5.0 mm, preferably 1.5 mm × 1.5 mm to 3.5 mm × 3.5 mm, and the wire mesh D is selected to have the appropriate number.

  Next, as shown in FIG. 6, the wooden mold 30 is placed on the base 52, and the periphery of the wooden mold 30 is surrounded by a sand mold preparing frame 53 so that the wooden mold 30 is located at the center. The casting sand 54 is filled so that the wooden mold 30 is embedded in the body 53. Next, the casting sand 54 filled in the sand mold preparation frame 53 is hardened to the shape by sealing with carbon dioxide gas. Thereafter, the sand mold preparation frame 53 is inverted and the wooden mold 30 is extracted, whereby a sand mold (inverted mold) having a cavity portion (a cavity having a reversed shape of the wooden mold 30) 55 as shown in FIG. ) 50 lower mold 51 is manufactured. As a result, the concavo-convex pattern transferred from the concavo-convex pattern forming member 40 is formed on the surface (surface) 56 facing the surface 31 of the wooden mold 30 in the lower mold 51 of the sand mold 50.

  Next, as shown in FIG. 8, the upper mold 57 of the sand mold 50 is manufactured. The upper mold 57 is formed with a gate 58 communicating with the cavity 55 of the lower mold 51. Although not shown, the upper mold 57 is manufactured in the same manner as the lower mold 51 using a gate for forming the gate 58.

  Next, the lower mold 51 and the upper mold 57 that are manufactured are combined to form a sand mold 50, and the convex mold 10 is manufactured by casting using the sand mold 50. That is, as shown in FIG. 9, the upper mold 57 is combined with the upper side of the lower mold 51 of the sand mold 50, the molten metal is poured into the hollow portion 55 from the gate 58 of the upper mold 57, and the molten metal is solidified to form the convex metal. The mold 10 is cast. Thereby, as shown in FIG. 1, the uneven | corrugated pattern transferred from the sand mold 50 is formed in the surface (molding surface) 11 facing the surface 56 of the sand mold 50 in the convex mold 10. The convex mold 10 is made of aluminum, aluminum alloy, or the like. Although not shown in the figure, the convex mold 10 is formed with a large number of vapor holes at appropriate pitches for introducing water vapor for heating the foamed resin particles with steam when forming the foam molded body.

  Although the method for manufacturing the convex mold 10 has been described above, the concave mold 20 is manufactured so as to have a concavo-convex pattern on the molding surface 21 as in the case of the convex mold 10, so the description is omitted here.

  According to the present embodiment, one surface (contact surface with the wire mesh D) 41 is an uneven surface to which the uneven pattern of the wire mesh D is transferred, and the opposite surface (contact surface with the press plate B) 44 is The concavo-convex pattern forming member 40 that is a smooth surface remains affixed to the surface 31 of the wooden mold 30 on the smooth surface side while the synthetic resin sheet 40 ′ is not pressed. Therefore, according to the present embodiment, it is possible to increase the adhesion area of the concavo-convex pattern forming member 40 to the surface 31 of the wooden mold 30, and the concavo-convex pattern forming member 40 is removed from the surface 31 of the wooden mold 30 when the wooden mold 30 is extracted. Will not peel off.

  Further, according to the present embodiment, the concave and convex portions 42 of the concave and convex pattern forming member 40 do not reach the smooth surface 44, and the concave portions 42 and so on are not through holes. Therefore, according to the present embodiment, since the concavo-convex pattern forming member 40 has no vertical crossing between the respective line portions constituting the mesh like a wire mesh, the concavo-convex pattern forming member 40 is attached in close contact with the wooden mold 30, Cast sand does not enter between the wooden mold 30 and the concavo-convex pattern forming member 40. Therefore, when the wooden mold 30 is extracted, problems such as the collapse of the sand mold 50 do not occur, and the convex mold 10 and the concave mold 20 having an extremely good uneven pattern can be manufactured.

  Further, according to the present embodiment, since the concave / convex pattern forming member 40 is made of a synthetic resin sheet, it has flexibility, and the concave portions 42,... Are densely formed on one surface 41 vertically and horizontally at regular intervals. Accordingly, the concave and convex portions 42,... Are thin-walled portions, so that the concavo-convex pattern forming member 40 is further flexible. Therefore, according to the present embodiment, it can be adhered and adhered so as to follow the surface of the curved wooden mold 30, without causing problems such as lifting from the surface 31 of the wooden mold 30, It can be applied to a model having a complicated surface with a three-dimensional shape.

  Further, according to the present embodiment, the uneven pattern of the metal mesh D is clearly transferred onto one surface 41 ′ of the synthetic resin sheet 40 ′ by hot pressing. Accordingly, since the uneven pattern can be clearly transferred to the sand mold 50 by the uneven pattern forming member 40, the uneven pattern can be clearly transferred to the convex mold 10 and the concave mold 20 cast using the sand mold 50. A concavo-convex pattern can be clearly formed on the surface of a foamed molded product molded using the mold 10 and the concave mold 20. In addition, when it is desired to finish the concavo-convex pattern softly (in order to reduce the sharpness (sharpness) of the concavo-convex pattern), the press pressure and the press temperature may be reduced.

  The description of the present embodiment is as described above, but the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.

  For example, in the above embodiment, the wire mesh D is used as an original plate having a concavo-convex pattern. However, the present invention is not limited to this, and a punching metal may be used, or the surface of a metal plate (for example, an aluminum plate) is cut to form a concavo-convex pattern. What was formed, what was etched with a chemical | medical agent etc. so that a concavo-convex pattern may be formed, or other things may be used.

  Moreover, in the said embodiment, although the uneven | corrugated pattern was formed in the molding surface whole surface of the convex mold 10 and the concave mold 20, only the convex mold, or only the concave mold, or the convex mold and / or Or you may make it form an uneven | corrugated pattern in a part of molding surface of a concave mold. In other words, in the above embodiment, the concave / convex pattern forming member 40 is pasted on the entire surface 31 of the wooden mold 30, but the concave / convex pattern forming member 40 is pasted on a part (predetermined range) of the front surface 31 of the wooden mold 30. It may be. The point is that in which range and where the uneven pattern is formed on the molding surface of the molding die is a matter determined by which range and where on the surface of the foamed molded product the uneven pattern is desired.

  In the above embodiment, the synthetic resin sheet 40 ′ laid on the wire mesh D is pressed between the foamed urethane sheet C and the Teflon (registered trademark) sheet E. It is needless to say that the sheet C and the Teflon (registered trademark) sheet E are not essential, and the press working conditions can be appropriately changed as necessary.

  DESCRIPTION OF SYMBOLS 10 ... Convex mold (convex mold), 11 ... Molding surface, 20 ... Concave mold (concave mold), 30 ... Wooden (model), 31 ... Surface, 40 '... Synthesis Resin sheet, 40 ... concave-convex pattern forming member, 41 ', 41 ... one surface, 42 ... concave portion, 43 ... convex portion, 44', 44 ... the other surface, 50 ... sand mold (reversed type), 51 ... lower mold, 52 ... Base, 53 ... Frame for sand mold preparation, 54 ... Cast sand, 55 ... Cavity, 56 ... Surface, 57 ... Upper mold, 58 ... Spout, A ... Base, B ... Press plate, C ... Urethane foam sheet, D ... Wire mesh, E ... Teflon (registered trademark) sheet

Claims (3)

A molding die for molding a foam molded article, having a concavo-convex pattern transferred from a concavo-convex pattern forming member using the model, pasting the concavo-convex pattern forming member on the entire surface or a predetermined range of the model surface In the manufacturing method of a molding die for manufacturing a reversal mold and further manufacturing a molding mold having a concavo-convex pattern transferred from the reversal mold using the reversal mold,
As the concavo-convex pattern forming member, the concavo-convex pattern of the original plate is embedded on one side by pressing a synthetic resin sheet laid on the original plate having the concavo-convex pattern using a press plate having a smooth surface. Using the transferred material, the concave / convex pattern forming member is attached to the surface of the model on the smooth surface opposite to the concave / convex surface to which the concave / convex pattern is transferred ,
Rukoto said to produce a reversal type, sampling a model pasted model the uneven pattern forming member after solidifying the molding sand filling the molding sand to fill the model enclosed by the frame member from the molding sand A method for producing a mold for molding.   The method for producing a molding die according to claim 1, wherein a thermoplastic synthetic resin sheet is used as the synthetic resin sheet, and pressing is performed while applying heat. The method for producing a molding die according to claim 1, wherein the original plate has a concavo-convex pattern in which concave portions and convex portions are alternately aligned.

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