JP2011037264A - Method for producing mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a mold without requiring complicated post-processing, the mold having excellent permeability and allowing uniform heating and cooling to be performed therein. <P>SOLUTION: The method for producing the mold comprises the steps of: impregnating a fibrous material such as a ceramic fiber, a carbon fiber and a metallic fiber with a solvent (for example, alcohols) containing a bond such as a novolac-type phenolic resin to prepare a coating material; applying a mold releasing agent onto the surface of an original mold 1; applying the coating material onto the applied mold releasing agent to form a coating layer 3 having a predetermined thickness; releasing the original mold 1 from the coating layer 3; and curing the coating layer 3 by heat treatment to produce a reverse mold. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a mold, and more particularly to a method for manufacturing a mold that requires air permeability and is used for molding a foamed resin or for molding a freeze casting system.

  Conventionally, mold-molded articles for molds such as olefin resins such as polyethylene and polypropylene, or polystyrene resins are filled with these pre-expanded particles in a mold and heated and fused with a heating medium such as water vapor. Manufactured.

  For example, in Patent Document 1, the maximum opening width of the steam blowing hole of the mold is 0.8 mm or less, and the opening ratio of the steam blowing holes on at least two front and back surfaces is the total area of the surface. A mold for producing a foamed resin block for a disappearing model, which is 4 to 25% of the above, has been proposed.

  Conventionally, a mold manufacturing method called a freeze casting system is known. This freeze casting system uses ice instead of a binder to ensure the strength of the mold, so that water is contained in the foundry sand, and cold air below 0 ° C. is sucked and passed through it, The strength of the mold is secured by freezing the mold.

  For example, Patent Document 2 discloses that low-temperature air of −3 ° C. or less cooled by a refrigerator is circulated in a mold and then collected, cooled again through a heat exchanger of the refrigerator, and circulated in the mold. A frozen mold manufacturing method has been proposed in which the mold is frozen by low-temperature air circulating in a closed system.

  Further, a general casting sand mold is produced by various methods such as a fresh sand mold casting method, a self-hardening mold casting method, a shell mold method, and a precision casting method.

  Among these, as described in Non-Patent Document 1, the shell mold method uses phenolic resin as a binder, fills a heated mold with a mixture of phenolic resin and foundry sand, and molds it. ing.

JP 2002-264163 A JP 11-138235 A

Edited by the Japan Foundry Association, “Revised 3rd Edition Casting Handbook” issued on May 20, 1973, p. 284-293

  By the way, in the mold for producing a foamed molded body, in order to heat uniformly, a vent is required as described in Patent Document 1, and even in the freeze casting system described in Patent Document 2, In order to spread the water evenly, a vent hole is required. And such an air vent is normally performed by post-processing after producing a type | mold.

  However, in the conventional mold manufacturing methods such as Patent Documents 1 and 2, depending on the mold shape, it may be difficult to make a vent hole at a desired position. For this reason, uniform heating or cooling is performed. It was sometimes difficult.

  Further, the shell mold method described in Non-Patent Document 1 can ensure air permeability through a gap formed between sand particles, but is applied to a mold for producing a molded body. There was a problem that the mechanical strength was not yet sufficient.

  As a method for improving the drawbacks of the shell mold method, a method of reinforcing the entire mold using the back mold shell mold method is also conceivable.

  However, this back mold shell molding method is effective for reinforcing the entire mold, but it is difficult to improve the mechanical strength of the cavity side surface.

  The present invention has been made in view of such circumstances, has a good air permeability without requiring complicated post-processing, and can perform heating and cooling in a mold uniformly. An object is to provide a manufacturing method.

  In order to achieve the above object, a mold manufacturing method according to the present invention is a mold manufacturing method for forming a molded body using an upper mold and a lower mold, and a solvent containing a binder is used. A coating material is prepared by impregnating a fibrous material, and after applying a release material on the surface of the original mold, the coating material is applied to form a coating layer, dried, and then the coating layer The original mold is released, and then the coating layer is cured by heat treatment to produce an inverted mold.

  The mold manufacturing method according to the present invention is a mold manufacturing method for forming a molded body using an upper mold and a lower mold, and the fibrous material is impregnated with a solvent containing a binder. The coating material is prepared, and a perforated thin plate member formed with a large number of small holes is formed into a shape corresponding to the original mold, and a release material is applied to the surface of the original mold. Is applied to form a coating layer, and then the formed perforated thin plate member is superposed on the surface of the coating layer and dried, and then the original mold is released from the coating layer, followed by heat treatment. The reversal type in which the coating layer and the perforated thin plate member are integrated is manufactured.

  Moreover, the manufacturing method of the type | mold of this invention is characterized by the said fibrous material containing either ceramic fiber, carbon fiber, and metal fiber.

  Furthermore, the mold manufacturing method of the present invention is characterized in that the binder is a novolac type phenol resin and the solvent is an alcohol.

  Moreover, the manufacturing method of the type | mold of this invention is characterized by making a granular substance build in the said coating layer, or making it adhere to the surface.

  The mold manufacturing method of the present invention is characterized in that a plurality of reinforcing members are erected on the coating layer.

  Further, in the mold manufacturing method of the present invention, a model in which a large number of openings are formed using an extinguishing material that disappears by pouring molten metal, the model is placed in foundry sand, The molten metal is poured into the model, the disappearing material is replaced with the molten metal, a support member is produced, and then the support member and the inversion mold are bonded via an adhesive. .

  Further, the mold manufacturing method of the present invention produces a model in which a large number of openings are formed using a disappearing material that disappears by pouring molten metal, and solder is applied to a part of the surface of the inversion mold. After coating, the model is placed on the inversion mold and placed in the foundry sand, molten metal is poured into the model and the vanishing material is replaced with the molten metal to form a support member, The reverse mold and the support member are thermally bonded through the solder.

  According to the production method of the above-mentioned type, a coating material is obtained by impregnating a fibrous material such as ceramic fiber, carbon fiber, and metal fiber with a solvent (for example, alcohols) containing a binder such as a novolak-type phenol resin. After applying a release material on the surface of the original mold, the coating material is applied to form a coating layer, and after drying, the original mold is released from the coating layer, and then heat-treated. The coating layer is cured to produce a reversal type, so that the air permeability can be ensured evenly and mechanically by the fibrous material forming the coating layer, even if the air holes are not formed by post-processing. A mold for producing a molded article with sufficient strength can be produced. In addition, since a fibrous material is impregnated with a solvent containing a binder and a coating material is applied to form a coating layer, a desired mold can be easily produced at low cost.

  In addition, according to the above-described mold manufacturing method, a fibrous material is impregnated with a solvent containing a binder to produce a coating material, and a perforated thin plate member in which a large number of small holes are formed corresponds to the prototype. After the mold is applied to the surface of the original mold, a release material is applied to the surface of the original mold, and then the coating material is applied to form a coating layer, and then the perforated thin plate member is formed on the surface of the coating layer. After being overlaid and dried, the original mold is released from the coating layer, and then heat-treated to produce an inverted mold in which the coating layer and the perforated thin plate member are integrated. This makes it possible to reduce the amount of solvent in the coating material. That is, since the amount of the solvent can be reduced, the drying time can be shortened without causing unevenness of drying, and thereby a uniform inverted mold in which surface irregularities are suppressed can be produced. Moreover, since the inversion type is reinforced with a thin plate member, the strength can be improved. As described above, according to the present invention, by integrating the thin coating layer and the thin plate member, a mold having good strength can be manufactured at a low cost without impairing the air permeability.

  Further, since the particulate material is incorporated in the coating layer or adhered to the surface, the strength of the mold can be further improved.

  Further, since the plurality of reinforcing members are erected on the coating layer, the strength of the mold can be further improved.

  Further, a model having a large number of openings formed using a disappearable material that disappears by pouring molten metal, and the model is placed in foundry sand, and the molten metal is poured into the model. Then, the disappearing material is replaced with the molten metal to produce a support member, and then the support member and the inversion mold are joined via an adhesive, so that the support member produced by the disappearance model casting method is bonded. It is possible to easily join the inversion type via the agent.

  Further, a model in which a large number of openings are formed using an extinguishing material that disappears by pouring molten metal, solder is applied to a part of the surface of the inversion type, and then the model is Placed in a reversal mold and placed in the foundry sand, poured molten metal into the model, replaced the vanishing material with the molten metal to form a support member, and the reversal mold through the solder Since the support member and the support member are thermally bonded, the inverted mold and the support member are joined in the foundry sand, and a desired mold can be easily manufactured by a simple manufacturing process.

It is sectional drawing which shows one Embodiment of the prototype used for this invention. It is sectional drawing which shows the state which formed the coating layer on the prototype. 1 is a cross-sectional view of an inversion type (first embodiment). It is sectional drawing which shows one Embodiment of the type | mold manufactured with the manufacturing method of this invention. It is sectional drawing which shows the preparation methods of the perforated thin plate member used for the 2nd Embodiment of this invention. It is a figure which shows the inversion type manufacturing method obtained in 2nd Embodiment. It is sectional drawing which shows the principal part process of 3rd Embodiment of the manufacturing method of this invention. It is sectional drawing of the type | mold manufactured with the manufacturing method of 3rd Embodiment. It is a figure shown with the manufacturing method of 4th Embodiment. It is a figure for demonstrating the measuring method of the bending strength performed in the Example.

  Next, the mold manufacturing method of the present invention will be described in detail with reference to the accompanying drawings.

  1 to 4 are sectional views showing a manufacturing procedure of a mold manufacturing method. In addition, although the following embodiment shows the manufacturing method of an upper mold | type, it can also manufacture by the same method also about a lower mold | type.

  First, as shown in FIG. 1, a prototype 1 formed in a predetermined shape is placed on a surface plate 2. Here, the material for producing the prototype 1 is not particularly limited, and for example, a wooden mold, a resin mold, a foam mold, or the like can be used.

  Next, a coating material is produced by impregnating the fibrous material with a solvent containing a binder.

  Here, the binder is not particularly limited as long as it has a heat resistance of about 120 ° C. in the case of a disappearance model formed in a high-temperature atmosphere. For example, heat such as a novolak-type phenol resin is used. A curable resin can be used. The solvent is not particularly limited as long as the binder can be dissolved, and for example, alcohols such as methanol and ethanol can be used. In this case, from the viewpoint of accelerating the curing of the curable resin with heat during heating, it is preferable to contain 10 to 30% by weight of hexamethylenetetramine in the binder.

  In addition, in the case of freeze casting in which molding is performed in a freezing atmosphere, an acrylic emulsion can be used as a binder, and water can be used as a solvent. Further, the mixing ratio of the binder and the solvent is not particularly limited as long as air permeability can be secured by volatilization or evaporation of the solvent, but the content of the binder is preferably 20 to 50% by weight. .

  From the viewpoint of improving mechanical strength, it is preferable that the binder contains refractory particles such as Cu powder having a maximum particle size of 300 μm or less.

  Further, the fibrous material is not particularly limited as long as air permeability can be secured after curing, and carbon fiber, metal fiber, ceramic fiber, a cloth mat, a wool mat, or the like can be used.

  Next, after applying a release material (not shown) to the surface of the original mold 2, the coating material is applied to form a coating layer 3 having a predetermined thickness (for example, about 1 mm) as shown in FIG. . Next, after the prototype 1 is released from the coating layer 3 after drying, the coating layer 3 is cured by heat treatment at a temperature of 250 to 300 ° C., and the inverted mold 4 is produced as shown in FIG.

  Then, as shown in FIG. 4, the support member 5 in which the rod-shaped members are arranged or the rod-shaped members are formed in a lattice shape to form the opening 20 and the reversal die 4 are joined via the adhesive 6. Thus, a mold for producing a molded body is produced.

  The support member 5 can be easily manufactured by using a well-known disappearance model method.

  That is, it is easily manufactured by embedding a model having an opening formed of polystyrene foam (disappearing material) in dry sand, pouring aluminum alloy (molten metal) and replacing the model with aluminum alloy. Can do.

  As described above, the mold manufacturing method of the present invention is to prepare a coating material by impregnating a fibrous material with a solvent containing a binder, and after applying a release material to the surface of the original mold 1, the coating material Is applied to form a coating layer 3 and dried, and then the original mold 1 is released from the coating layer 3. Thereafter, the coating layer 3 is cured by heat treatment to produce an inversion type. Even if the air holes are not formed by post-processing, the fibrous material forming the coating layer can ensure a uniform air permeability and can produce a mold for producing a molded article with sufficient mechanical strength. . Moreover, since the coating material 3 is formed by impregnating the fibrous material with a solvent containing a binder, the coating layer 3 is formed, so that a desired mold can be easily manufactured at low cost.

  Next, another example of the inversion type will be described as the second embodiment.

  FIG. 5 shows a method for producing a perforated thin plate member used in the second embodiment, FIG. 5 (a) is a plan view, and FIG. 5 (b) is a front sectional view.

  That is, the perforated thin plate member 7 is made of a metal material such as aluminum or stainless steel, has a predetermined thickness (for example, 0.5 to 1.0 mm), and has a large number of small holes 8 (for example, a hole diameter of 3 mm). It is installed. As the perforated thin plate member 7, for example, a punching metal or a wire mesh with a mesh hole penetrating it can be used. And as shown in FIG.5 (b), it shape | molds in the shape corresponding to the original pattern 1 by methods, such as a spatula process and hammering.

  FIG. 6 is a diagram showing an inversion type manufacturing method.

  First, as shown in FIG. 6 (a), after placing the original mold 1 on the surface plate 2, a release material (not shown) is applied to the surface of the original mold 1, and then the same as in the first embodiment. A coating material is applied to form a thin coating layer 9 (for example, about 0.3 mm).

  Next, as shown in FIG. 6B, after the perforated thin plate member 7 is overlaid and dried on the coating layer 9, the prototype 1 is released from the coating layer 9, and then heat-treated at a temperature of 250 to 300 ° C. Then, the coating layer 9 is cured, and as shown in FIG. 6C, the reversal mold 30 in which the coating layer 9 and the perforated thin plate member 8 are integrated is manufactured.

  Thus, in the second embodiment, a fibrous material is impregnated with a solvent containing a binder to produce a coating material, and a perforated thin plate member 7 in which a large number of small holes 8 are formed is a prototype. 1 is applied to the surface of the original mold 1, and then the coating material is applied to form the coating layer 9, and then the perforated thin plate member 7 is formed. After being superposed on the surface of the coating layer 9 and drying, the original mold 1 is released from the coating layer 9 and then heat-treated, so that the reversal mold 30 in which the coating layer 9 and the perforated thin plate member 7 are integrated is produced. The coating layer 9 can be made thin, and thereby the amount of solvent in the coating material can be reduced. That is, when the amount of the solvent in the binder increases, the drying time becomes longer, and drying unevenness occurs and the surface becomes uneven. However, in this second embodiment, the amount of solvent can be reduced, so that drying unevenness does not occur and the drying time can be shortened, thereby producing a homogeneous inversion type with suppressed surface irregularities. be able to. Moreover, since the reversal mold 30 is reinforced by the perforated thin plate member 7, the strength can be improved.

  As described above, according to the second embodiment, by integrating the thin coating layer 9 and the perforated thin plate member 7, a mold having good strength can be obtained at low cost without impairing air permeability. It can be manufactured.

  FIG. 7 is a cross-sectional view showing a main process of the third embodiment.

  That is, in the third embodiment, after the coating layer 3 is formed on the master 1 by the same method as in the first embodiment, the plate-like reinforcing member 10 having a rectangular cross section is partially formed on the coating layer 3. Is erected on the coating layer 3 so as to enter the inside of the coating layer 3. In FIG. 7, reference numeral 11 denotes a raw material (for example, foamed bead) inlet for manufacturing a molded body.

  Subsequently, after the prototype 1 is released from the coating layer 3 after drying, the coating layer 3 is cured by heat treatment at a temperature of 250 to 300 ° C., and as shown in FIG. 8, the cured layer 12 and the plate-like reinforcing member 10 is produced.

  Then, after that, as in the first embodiment, an appropriate support member is manufactured, and thereby a desired mold can be manufactured.

  In the third embodiment, since a plurality of plate-like reinforcing members 10 are erected on the surface of the coating layer 3, in addition to the operational effects of the first embodiment, the strength of the mold is further improved. Can be achieved.

  In the third embodiment, the inversion mold 4 manufactured in the first embodiment is used. However, the same applies to the use of the inversion mold 30 manufactured in the second embodiment. Needless to say.

  Next, the fourth embodiment will be described in detail using the inversion type manufactured in the first embodiment.

  FIG. 9 shows a manufacturing method according to the fourth embodiment.

  That is, as shown in FIG. 9A, lead-free solder (Al solder, tin-zinc solder) is applied to a part of the surface of the reversal mold 4 placed on the surface plate 2 to form a solder layer 14. To do.

  And as shown in FIG.9 (b), the model 15 which has the opening part formed with the polystyrene foam (disappearance material) is mounted in the surface of the inversion type | mold 4, and this is the foundry sand (dry sand) 16 which dried. Is disposed at a predetermined position in the casting frame 17 filled with the.

  When a molten metal 19 such as an aluminum alloy is poured from the gate 18, the molten metal 19 is guided to the runner 21 and poured into the model 15, and the model 15 disappears and is replaced with the molten metal 19. Then, the molten metal 19 is solidified by leaving it for a predetermined time, and then the mold is taken out from the casting frame 17, whereby a mold similar to that shown in FIG. 4 can be manufactured.

  The present invention is not limited to the above embodiment. For example, it is preferable that aluminum particles (granular material) having a maximum particle size of 0.6 to 1.0 mm be sprayed on the coating layer 3 to be present inside the coating layer 3 or to be fixed to the surface. As a result, the mechanical strength can be further improved.

  In the third and fourth embodiments, the inversion type 4 manufactured in the first embodiment is used. However, the same applies to the inversion type 30 manufactured in the second embodiment. Needless to say.

  Next, examples of the present invention will be specifically described.

  A methanol solution containing 30% by weight of a novolac-type phenolic resin was prepared, and Cu powder was added to the methanol solution so that the methanol solution and the Cu powder were in a weight ratio of 2: 1. A binder solution was prepared.

  Then, as shown in FIG. 10A, a carbon cloth having a length L of 120 mm and a width W of 30 mm was prepared, and a binder solution was applied to both surfaces of the carbon cloth. Next, three carbon cloths coated with this binder solution were stacked to prepare a sample of Example 1 having a thickness of 1 mm.

  Also, an acrylic emulsion aqueous solution containing 50% by weight of the acrylic emulsion is prepared, an acrylic emulsion aqueous solution and Cu powder are prepared, and the acrylic emulsion aqueous solution and Cu powder are in a weight ratio of 2: 1. Cu powder was contained in the emulsion aqueous solution, thereby producing a binder solution.

  And the carbon cloth of the dimension similar to Example 1 was prepared, and the binder solution was apply | coated to both surfaces of this carbon cloth. Next, three carbon cloths coated with this binder solution were stacked to prepare a sample of Example 2 having a thickness of 1 mm.

  A sample (sand mold) of Comparative Example 1 having a length L of 120 mm, a width W of 30 mm, and a thickness T of 5 mm was produced by a shell mold method.

  Next, as shown in FIG. 10B, the fulcrum length L ′ was set to 100 mm, the pressure P was applied to the center portion, and the bending strength was measured using only the spring.

  Table 1 shows the measurement results.

As is apparent from Table 1, the sample of Comparative Example 1 produced by the shell mold method had a bending strength of 4.9 × 10 ^{6 to} 9.9 × 10 ⁶ Pa, whereas the present invention was carried out. The sample of Example 1 is 1.67 × 10 ^{8 to} 1.86 × 10 ⁸ Pa, and the sample of Example 2 of the present invention is 4.9 × 10 ^{7 to} 9.9 × 10 ⁷ Pa. It has been found that the mold manufactured by the manufacturing method of the invention has dramatically improved mechanical strength as compared with the conventional shell mold method.

DESCRIPTION OF SYMBOLS 1 Prototype 3 Coating layer 4 Inversion type 5 Support member 7 Perforated thin plate member 8 Small hole 9 Coating layer 10 Plate-shaped reinforcing member (reinforcing member)
20 Opening 30 Inversion type

Claims (8)

A mold manufacturing method for forming a molded body using an upper mold and a lower mold,
A fibrous material is impregnated with a solvent containing a binder to produce a coating material. After a mold release material is applied to the original surface, the coating material is applied to form a coating layer and dried. Thereafter, the original mold is released from the coating layer, and then the coating layer is cured by heat treatment to produce a reversal mold. A mold manufacturing method for forming a molded body using an upper mold and a lower mold,
A fibrous material is impregnated with a solvent containing a binder to prepare a coating material, and a perforated thin plate member in which a large number of small holes are formed is formed into a shape corresponding to the original shape. After applying a release material on the surface, the coating material is applied to form a coating layer, and then the formed perforated thin plate member is overlaid on the surface of the coating layer and dried, and then the coating is performed. A method for producing a mold, wherein the mold is released from a layer, and then heat-treated to produce an inverted mold in which the coating layer and the perforated thin plate member are integrated.   The mold manufacturing method according to claim 1, wherein the fibrous material includes any one of ceramic fiber, carbon fiber, and metal fiber.   The method for producing a mold according to any one of claims 1 to 3, wherein the binder is a novolak type phenol resin, and the solvent is an alcohol.   The method for producing a mold according to any one of claims 1 to 4, wherein a particulate substance is built in or adhered to the surface of the coating layer.   6. The mold manufacturing method according to claim 1, wherein a plurality of reinforcing members are erected on the coating layer.   A model in which a large number of openings are formed using a material that disappears by pouring of molten metal is prepared, the model is placed in foundry sand, and the molten metal is poured into the model, The vanishing material is replaced with the molten metal to produce a support member, and then the support member and the inversion mold are joined via an adhesive. A method for producing the described mold.   A model in which a large number of openings are formed using an extinguishing material that disappears by pouring molten metal, and solder is applied to a part of the surface of the inversion type, and then the model is converted into the inversion type. Placed on the casting sand, poured molten metal into the model, replaced the vanishing material with the molten metal to form a support member, and the inverted mold and the support via the solder The mold manufacturing method according to claim 1, wherein the member is thermally bonded to the member.

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