JP6016744B2 - Mold production equipment - Google Patents

Description

  The present invention relates to an apparatus for producing a mold used for casting.

  Conventionally, to manufacture a mold using a coated sand prepared by coating a binder with a binder such as a thermosetting resin, the coated sand is supplied into a cavity of a heated mold, The binder is heat-cured by heating, and the aggregate is bonded with the cured binder to produce a casting.

  According to this, it is possible to produce a mold with good productivity and stable quality, but since it is necessary to heat the mold to a high temperature, a thermosetting resin such as a phenol resin used as a binder for the coated sand is used. There is a problem that harmful substances such as ammonia and formaldehyde are generated by reaction, and the working environment is deteriorated. Also, the portion of the coated sand that contacts the mold is heated rapidly, so that the produced mold is warped. There is a problem that deformation is likely to occur.

  As a solution to the above problem, for example, the following Patent Document 1 has been proposed. This is a method of manufacturing a mold by filling the coated mold with coated sand and then blowing water vapor into the mold to heat the coated sand in the mold with water vapor to cure the binder. . According to this method, since the coated sand is heated by the heat of water vapor, it is possible to prevent harmful substances from being generated from the coated sand in contact with a high-temperature mold.

  However, in the method of Patent Document 1, water vapor is supplied into the mold from one or at most several supply holes provided in the mold. There is a problem that it is difficult to spread water vapor everywhere, and it is difficult to uniformly heat the entire coated sand in the mold.

  As a method for dealing with such a problem, for example, the following Patent Document 2 has been proposed. This is because the mold heating cavity path is provided with a plurality of steam introduction paths between the mold heating cavity path and the cavity, and a plurality of water vapors are provided through the mold heating cavity path. It is a manufacturing apparatus of the casting_mold | template supplied into a cavity from a steam introduction path. According to this manufacturing apparatus, it is possible to uniformly supply water vapor to the entire inside of the cavity and uniformly heat the entire coated sand in the cavity.

JP 2000-107835 JP2011-230180A

  However, in the method of Patent Document 2, since steam is blown out from the steam introduction path into the cavity, even if the inner diameter of the steam introduction path is larger than the diameter of the coated sand, the coated sand enters the steam introduction path. However, the coated sand filled in the cavity is held in a pressurized state in the mold, and steam is not always supplied from the steam introduction path in the molding process of the mold. Therefore, there is a problem that the coated sand gets into the steam introduction path and becomes clogged. Further, when water vapor is supplied from the steam introduction path into the cavity, the water vapor directly hits the surface of the mold, so that there is a problem that the casting surface of the portion directly exposed to the water vapor deteriorates. In addition, there is a problem that the shape of the mold is complicated and it is difficult to manufacture and maintain the mold.

  In view of the above problems, the present invention can be manufactured without clogging the coated sand filled in the mold, and can uniformly heat the entire coated sand, thereby producing a uniform mold with a good appearance. An object of the present invention is to provide a manufacturing apparatus.

  Means for solving the above problems will be described with reference numerals in the embodiments described later. As shown in FIG. 1 to FIG. 1 is formed, and the molding die 3 having an infinite number of ventilation holes 2 and the entire inner surface of the molding die 3 excluding the sand supply port 10 side are stretched, allowing air to pass but not coated sand 4 particles. Superheated steam 7 enters the cavity 1 through the mesh member 5, the coated sand supply unit 6 that supplies the coated sand 4 into the cavity 1, and the ventilation hole 2 of the mold 3 and the mesh member 5 from around the mold 3. The gas supply unit 8 supplies gas and the gas discharge unit 9 discharges the gas 7 from the cavity 1.

  According to a second aspect of the present invention, in the mold manufacturing apparatus according to the first aspect, the hole diameter of the vent hole 2 of the mold 3 is larger than the average particle diameter of the coated sand 4.

  A third aspect of the present invention is the mold manufacturing apparatus according to the first or second aspect, wherein the mesh member 5 has an opening of 200 μm or less.

According to a fourth aspect of the present invention, in the mold manufacturing apparatus according to any one of the first to third aspects, a ratio of the total area of the openings of the vent holes 2 and 22 to the area of the inner peripheral surface of the cavity 1 is 100: 0. It exists in the range of 01-100: 10, It is characterized by the above-mentioned.

A fifth aspect of the present invention provides the mold manufacturing apparatus according to any one of the first to fourth aspects, wherein the gas supply section 8 includes a gas introduction section 13 provided along the outer periphery of the mold 3. It is said.

A sixth aspect of the present invention is the mold manufacturing apparatus according to the fifth aspect , wherein the gas supply unit 8 is provided with pressure adjusting means.

A seventh aspect of the present invention is the mold manufacturing apparatus according to any one of the first to sixth aspects, further comprising suction means for sucking the gas 7 discharged to the gas discharge portion 9.

An eighth aspect of the present invention is the mold manufacturing apparatus according to any one of the first to seventh aspects, wherein the mold is removed with the pressure of the gas 7.

Claim 9 is the mold manufacturing apparatus according to any one of claims 1 to 8 , wherein the gas 7 is an amine, an ester, a carbon dioxide gas, water vapor, superheated water vapor, air, heated air, an inert gas, It is at least one selected from heated inert gas.

A tenth aspect of the present invention is the mold manufacturing apparatus according to any one of the first to ninth aspects, wherein the binder of the coated sand 4 is a phenol resin, a urethane resin, a saccharide, a protein, water glass, or an inorganic salt. It is characterized by being.

  The effect of the invention by the above-described solution means will be described with reference to the embodiment described later, and when superheated steam 7 is used as the gas. As shown in FIG. 4, a mesh member 5 is stretched over the entire inner surface of the molding die 3 excluding the sand supply port 10 side in the molding die 3 in which the cavity 1 is formed and the air holes 2 are formed innumerably. Then, the coated sand 4 in the cavity 1 is heated by supplying the gas 7 from the gas supply unit 8 from the periphery of the mold 3 into the cavity 1 through the vent hole 2 and the mesh member 5. Since the mesh member 5 allows air to pass but does not allow the particles of the coated sand 4 to pass through, the coated sand 4 supplied into the cavity 1 does not clog the vent hole 2 of the mold 3, and the superheated steam 7 It can be effectively supplied into the cavity 1 from the vent hole 2 of the mold 3 through the mesh member 5 and can be distributed to every corner of the coated sand in the cavity, whereby the coated sand 4 can be heated more uniformly. Thus, a homogeneous mold can be produced. Further, since the superheated steam 7 has a remarkably large heat capacity compared to high-temperature air or saturated steam at the same temperature, the entire coated sand 4 in the cavity 1 can be instantaneously heated to cure the binder, A mold can be manufactured in a short time. The vent hole 2 is usually a round hole having a circular cross section, but may be a slit. Further, the infinitely formed air holes 2 are specifically 50 or more, more preferably 100 or more.

  In addition, when a mold is produced many times, when the coated sand 4 particles adhere to the mesh member 5 and become stuck, or when a part of the mesh member 5 is torn, the mesh member By removing 5 from the mold 3, it can be easily replaced with a new one. In this case, since the mesh member 5 is stretched on the inner surface side of the mold 3, the hole diameter of the vent hole 2 may be smaller or larger than the average particle diameter of the coated sand 4.

  As described in claim 2, when the mesh member 5 is stretched on the inner surface of the mold 3, if the hole diameter of the vent hole 2 of the mold 3 is larger than the average particle diameter of the coated sand 4. Compared with the case where the air holes 2 having a diameter smaller than the average particle diameter of the coated sand 4 are formed, the number of the air holes 2 formed in the entire mold 3 can be reduced. Since the vent hole 2 is mechanically drilled by a laser processing machine or the like, if the number of the vent holes 2 to be drilled can be reduced, the labor saving of the drilling operation can be achieved. Moreover, hole cleaning becomes easy by making the hole diameter of the vent hole 2 larger than the average particle diameter of the coated sand 4.

  As described in claim 3, by setting the mesh member 5 to have an opening of 200 μm or less, the particles of the coated sand 4 can be reliably prevented from passing and air can be allowed to pass through.

As described in claim 4 , the ratio of the total area of the openings of the vent holes 2 and 22 to the area of the inner peripheral surface of the cavity 1 is in the range of 100: 0.01 to 100: 10. Therefore, the superheated steam 7 sufficient for molding the mold can be supplied into the cavity 1 with respect to the capacity, and stable heating can be performed.

As described in claim 5 , as a part of the gas supply unit 8, the gas introduction unit 13 is provided along the outer periphery of the molding die 3, so that the superheated steam 7 is transferred from the gas introduction unit 13 to the molding die 3. Each vent hole 22 can be passed uniformly, whereby the entire coated sand 4 in the cavity 1 can be heated more uniformly.

According to the sixth aspect of the present invention, the pressure of the superheated steam 7 supplied from the gas supply unit 8 is adjusted to be constant by providing the gas supply unit 8 with the pressure adjusting means, and the cavity passes through the vent holes 2 and 22. The superheated steam 7 supplied to the inside 1 can be stably supplied from all the vent holes 2 while suppressing variations in supply pressure.

According to the seventh aspect , by providing the suction means for sucking the gas discharged to the gas discharge portion 9, the superheated steam 7 supplied into the cavity 1 passes through the cavity 1 earlier and the molding die 3. While the inside heating is promoted, the effect of the mold can be promoted by discharging excess superheated steam 7.

According to the eighth aspect of the present invention, the mold can be easily released from the mold by removing the mold with the pressure of the gas 7, and the pressure of the gas can be reduced without providing an ejector pin depending on the shape of the cavity 1 of the mold 3. The mold can be released only by this, and the mold 3 can be simplified.

As described in claim 9 , the gas 7 supplied into the cavity 1 is not limited to superheated water vapor, but is also amines, esters, carbon dioxide gas, water vapor, superheated water vapor, air, heated air, inert gas, non-heated gas. It is good to be at least one selected from active gases. In addition, as described in claim 10 , the binder of the coated sand 4 may be a phenol resin, a urethane resin, a saccharide, a protein, water glass, or an inorganic salt.

  As a combination of the gas and the binder, for example, the coated sand coated with a thermosetting resin binder is cured by heating the coated sand using superheated steam, heated air, or a heated inert gas, It may be cured using amines or esters. In addition, the coated sand coated with water-soluble thermosetting resin, saccharide, protein, water glass or inorganic salt is moistened with water vapor, superheated water vapor, air, heated air, heated inert gas, etc. It may be cured by drying. At this time, not only curing by gas supply but also curing by heating in the mold by adjusting the temperature of the mold may be used.

It is sectional drawing which shows the whole mold manufacturing apparatus concerning 1st embodiment of this invention. It is a disassembled perspective view which shows the shaping | molding die and mesh member of a mold manufacturing apparatus same as the above. It is sectional drawing which shows operation | movement of the same mold manufacturing apparatus. It is sectional drawing which shows operation | movement of the same mold manufacturing apparatus. It is sectional drawing similar to FIG. 1 which shows the whole mold manufacturing apparatus concerning 2nd embodiment of this invention. It is sectional drawing similar to FIG. 3 which shows operation | movement of the mold manufacturing apparatus same as the above. It is sectional drawing similar to FIG. 4 which shows operation | movement of the mold manufacturing apparatus same as the above.

  A preferred first embodiment of the present invention will be described below with reference to the drawings. In the present embodiment, the mold is manufactured by curing the coated sand by supplying superheated steam as a gas. First, a mold manufacturing apparatus having a mesh member on the inner surface of the mold will be described. This manufacturing apparatus includes a mold 3 in which a cavity 1 is formed and an infinite number of air holes 2 are formed, and a sand supply port 10. A mesh member 5 which is stretched over the entire inner surface of the mold 3 except the side and allows air to pass but does not allow particles of the coated sand 4 to pass through; a coated sand supply unit 6 for supplying the coated sand 4 into the cavity 1; A superheated steam supply unit (gas supply unit) 8 that supplies superheated steam (gas) 7 into the cavity 1 from the periphery of the mold 3 through the vent hole 2 of the mold 3, and the superheated steam 7 is discharged from the cavity 1. And a superheated steam discharge section (gas discharge section) 9 that performs the above operation. As shown in FIG. 1, an upper plate 11 having a sand supply port 10 is disposed in the mold 3 so as to close the upper end opening of the cavity 1.

  If it demonstrates in detail about the structure of the manufacturing apparatus of the said mold, as shown in FIG. 2, the shaping | molding die 3 will consist of a pair of split molds 31 and 32, and by connecting both split molds 31 and 32, As shown in FIG. 1, for example, a cylindrical cavity 1 is formed inside. Each of the split dies 31, 32 includes a bottomed semi-cylindrical mold body 31a, 32a and box-shaped frame parts 31b, 32b integrally formed in a box shape on the back side of the mold body 31a, 32a. And back plates 33 and 34 for closing the back side openings of the box-shaped frame portions 31b and 32b, and innumerable ventilation holes 2 are formed in the bottomed semi-cylindrical mold main body portions 31a and 32a. Has been. The vent hole 2 is drilled by a lathe machine for drilling so as to linearly penetrate the inner and outer surfaces of the mold body portions 31a and 32a. The vent hole 2 is usually a round hole having a circular cross section, but may be a slit having a cut shape, and this slit can be easily drilled by a lathe machine or a laser machine.

  The hole diameter of the vent hole 2 is larger than the average particle diameter of the coated sand 4 and is, for example, 2.5 mm. Thus, when the hole diameter of the vent hole 2 is larger than the average particle diameter of the coated sand 4, the hole diameter is drilled in the mold 3 with a lathe as compared with the case where the hole diameter is formed as small as about 0.2 mm, for example. Therefore, the number of vent holes 2 to be reduced can be reduced, and therefore the perforating operation is simplified accordingly. Moreover, hole cleaning becomes easy by enlarging the hole diameter of the ventilation hole 2 in that way. In this way, the hole diameter of the air hole 2 can be made larger than the average particle diameter of the coated sand 4, for example, about 2.5 mm. Air can be passed through the inner surface side of the mold 3, but particles of the coated sand 4 can not be passed. This is because the mesh member 5 is provided.

  The coated sand 4 is prepared by coating an aggregate such as quartz sand with a binder such as a thermosetting resin. As the thermosetting resin, a phenol resin, an isocyanate compound, an amine polyol resin, or the like is used. The average particle size of the coated sand 4 is about 400 to 600 μm (for example, 500 μm) for a coarse one and about 250 to 350 μm (for example, 300 μm) for a fine one.

  As shown in FIG. 2, the mesh member 5 stretched on the inner surface of the mold 3 includes a pair of halves 51 and 52, and each of the halves 51 and 52 includes half cylinders 51 a and 52 a, It consists of semicircular bottom portions 51b and 52b, and is stretched so as to be in close contact with the inner surfaces of the halves 51 and 52 of the molding die 3, respectively. The mesh member 5 is made of, for example, a stainless steel wire mesh, and the thickness thereof is, for example, 0.35 mm. The mesh opening is smaller than the average particle size of the coated sand 4 and the average particle size of the binder-coated sand. The diameter is preferably 200 μm or less, for example, about 150 to 180 μm. The halves 51 and 52 are provided with projecting pieces 51c and 52c on both sides of the semi-cylindrical portions 51a and 52a. In addition, the ratio of the area of the inner peripheral surface of the cavity 1 at this time to the total area of the openings of the vent holes 2 opening in the inner periphery of the cavity 1 (opening portions of the mesh member 5) is 100: 0.01 to 100: It may be in the range of 10, for example, about 100: 1 to 100: 3.

  In order to stretch the mesh member 5 on the inner surface of the mold 3, the half cylinders 51 a and 52 a and the semicircular bottom parts 51 b and 52 b of the half halves 51 and 52 are formed by molds 31 and 32. The main body portions 31a and 32a are in close contact with the entire inner surface and attached by, for example, welding, and the protruding pieces 51c and 52c are in close contact with the opposing wall surface portions 31c and 32c of the halves 51 and 52, respectively. The overhanging pieces 51c and 52c are sandwiched between the opposing wall surface portions 31c and 32c of the halves 51 and 52 when the halves 51 and 52 are connected.

  The mesh member 5 allows air to pass but does not allow the coated sand 4 particles to pass therethrough, and is not limited to the wire mesh used in this embodiment as long as it is a sheet and has high heat resistance. Good.

  As shown in FIG. 1, the coated sand supply unit 6 includes a hopper 61 for storing the coated sand 4, and a shutter 62 provided at the lower end of the hopper 61. The sand 4 is supplied through a sand supply port 10 provided in the upper plate 11 of the mold 3. Further, the coated sand 4 may be preheated to 30 ° C. to 100 ° C. in the coated sand supply unit 6.

  The superheated steam supply section (gas supply section) 8 supplies superheated steam 7 from the periphery of the mold 3 into the cavity 1 through the vent 2 and the mesh member 5 of the mold 3 as shown in FIG. In addition, the superheated steam generator 12, the superheated steam introduction part (gas introduction part) 13 provided along the outer periphery of the mold 3, and the superheated steam 7 generated by the superheated steam generator 12 are used as the superheated steam introduction part 13. The superheated steam pipe portion 14 is connected to the superheated steam pipe portion 14, and a valve 15 is provided at the inlet of the superheated steam pipe portion 14. The superheated steam 7 is supplied to the superheated steam introducing section 13 through the superheated steam piping section 14, and the superheated steam 7 supplied to the superheated steam introducing section 13 passes through the vent hole 2 formed innumerably in the mold 3. Filtered, and is supplied to the cavity 1 through the mesh member 5. Here, the superheated steam supply section 8 may be provided with a pressure adjusting means, and at least one of the paths from the superheated steam generator 12 to the superheated steam introduction section 13 through the superheated steam piping section 14. For example, the valve 15 may be a pressure regulating valve. By using the pressure adjusting means, the pressure of the superheated steam 7 supplied from the superheated steam supply section 8 is adjusted to be constant, and the superheated steam 7 supplied from the superheated steam introduction section 13 to the cavity 1 through the vent hole 2. Thus, stable superheated steam 7 can be supplied from all the vent holes 2 while suppressing variations in supply pressure.

  The superheated steam generator 12 is a superheated steam generator using electromagnetic induction heating, and can generate superheated steam at, for example, 500 ° C. with high efficiency of 90% or more directly from water. Incidentally, a conventional type of superheated steam generator produces saturated steam with a boiler heated with fossil fuel, etc., and reheats it with fossil fuel, etc. to produce superheated steam. %.

  As shown in FIGS. 1 and 2, the superheated steam introduction portion 13 is provided inside box-shaped frame portions 31 b and 32 b that are integrally formed on the back side of the mold main body portions 31 a and 32 a of the split dies 31 and 32. The back surface portion is closed by back plates 33 and 34, and the outlet end portion 14 o of the superheated steam pipe portion 14 passes through the back plates 33 and 34.

  As shown in FIG. 1, the superheated steam discharge unit 9 has a suction pump 16, and this suction pump 16 is connected to a wide-mouth duct 18 provided below the bottom of the mold 3 via a tubular suction duct 17. It is connected. The wide opening duct 18 is formed in a wide opening so as to face a large number of vent holes 2 for discharging superheated steam disposed at the bottom of the mold 3. The superheated steam discharge section 9 is not limited to forcibly discharging the superheated steam 7 in the cavity 1 with the suction pump 16, but may be configured to naturally exhaust through the vent hole 2 and the mesh member 5 of the mold 3. .

  Manufacturing of a mold by using the mold manufacturing apparatus configured as described above will be described below with reference to FIGS.

  First, as shown in FIG. 3, when the shutter 62 is opened in a state where the coated sand supply unit 6 is connected to the sand supply port 10 of the mold 3, the coated sand 4 in the hopper 61 passes through the sand supply port 10. 3 cavities 1 are supplied. At this time, if the inside of the hopper 61 is pressurized with high-pressure air and the coated sand 4 is sprayed into the cavity 1, the coated sand 4 can be efficiently supplied into the cavity 1.

  When the supply of the coated sand 4 into the cavity 1 is finished, as shown in FIG. 4, the coated sand supply unit 6 is separated from the sand supply port 10 of the mold 3, and the sand supply port 10 is closed, for example. 19, the valve 15 of the superheated steam supply unit 8 is opened to supply the superheated steam 7 into the cavity 1. When the superheated steam 7 is supplied from the superheated steam supply unit 8, the superheated steam 7 supplied into the cavity 1 is activated by operating the suction pump 16 of the superheated steam discharge unit 9. It passes between the particles and is forcibly discharged from the superheated steam discharge vent 2 at the bottom of the mold 3. The superheated steam 7 may be naturally exhausted without operating the suction pump 16.

  The supply process of the superheated steam 7 will be further described. The superheated steam 7 from the superheated steam generator 12 is supplied to the superheated steam introduction section 13 through the superheated steam piping section 14. Since the superheated steam introducing portion 13 is provided along the outer periphery of the mold 3, the superheated steam 7 supplied into the superheated steam introducing portion 13 is formed with countless vent holes 2. The entire outer periphery of the mold 3 is covered, passes through the ventilation holes 2 of the mold 3 uniformly, and further passes through the mesh member 5 stretched on the inner surface of the mold 3 to enter the cavity 1. The entire coated sand 4 can be uniformly heated by flowing in and reaching every corner of the coated sand 4 supplied into the cavity 1.

  In this case, the superheated steam 7 is supplied into the cavity 1 at a temperature equal to or higher than the curing temperature of the thermosetting resin that is the binder of the coated sand 4. The temperature of the superheated steam 7 is set to a required temperature within a range of 300 to 500 ° C., for example. Moreover, the pressure of the superheated steam 7 is set to a required pressure within a range of 0.15 to 0.8 MPa, for example. This pressure is preferably supplied to the superheated steam supply unit 8 by adjusting the pressure to a constant pressure by providing pressure adjusting means.

  The superheated steam 7 is high-temperature steam obtained by heating water molecules (not including air) boiled and vaporized at 100 ° C. to 100 ° C. or higher at normal pressure, compared to high-temperature air or saturated steam at the same temperature. It has about four times the heat capacity. Accordingly, by supplying such superheated steam 7 into the cavity 1 of the mold 3 at a required temperature and pressure, the entire coated sand 4 in the cavity 1 is instantaneously heated to cure the binder. Can do. Therefore, it is not necessary to preheat the mold 3 and the mold can be manufactured stably in a short time.

  In the mold manufacturing apparatus described above, the mesh member 5 that allows air to pass but does not allow particles of the coated sand 4 to pass through is stretched across the entire inner surface of the mold 3 except the sand supply port 10 side. The mesh member 5 can prevent the coated sand 4 from being clogged into the vent hole 2. Further, when the mesh member 5 is made of a wire mesh having a mesh smaller than the average particle diameter of the coated sand 4, the wire mesh itself of the mesh member 5 is a thin sheet having a thickness of 1 mm or less. These particles are difficult to clog, and when clogged, clogging can be easily eliminated by cleaning with a brush or the like.

  In addition, when a mold is produced many times, when the coated sand 4 particles adhere to the mesh member 5 and become stuck, or when a part of the mesh member 5 is torn, the mesh member By removing 5 from the mold 3, it can be easily replaced with a new one. For example, if the mold is formed of a porous material made of sintered metal and the pore is a vent, the pores of the porous material are clogged with coated sand particles. When it can no longer be used, it is necessary to replace the mold itself, which is very uneconomical. In this respect, since only the mesh member 5 needs to be replaced, it is extremely economical.

  After the superheated steam 7 is supplied into the cavity 1 to cure the coated sand 4, the coated sand supply unit 6 is removed from the sand supply port 10 of the mold 3, and the upper plate 11 covering the upper part of the mold 3 is removed. With the superheated steam supply section 8 and the superheated steam discharge section 9 separated appropriately from the split molds 31 and 32 of the mold 3, the split molds 31 and 32 of the mold 3 are pulled apart to form a mold. Open and remove the mold. In addition, when the supply pressure of the superheated steam 7 was set to about 0.4 MPa, for example, the mold formed in the cavity 1 was excellent in mold release.

  Further, when it is necessary to preheat the mold 3 prior to the production of the mold, by supplying the superheated steam 7 into the cavity 1 with the superheated steam supply unit 8 set in the mold 3, The entire mold 3 can be heated with the superheated steam 7. Therefore, there is an advantage that a heating device such as a heater for preheating the mold 3 is not required.

  As described above, the mold manufacturing apparatus provided with the mesh member 5 that allows air to pass through the inner surface side of the mold 3 but does not allow the particles of the coated sand 4 to pass therethrough has been described. An apparatus for producing a mold that does not have the mesh member 5 will be described with reference to FIGS. Note that the mold manufacturing apparatus according to the second embodiment does not include the mesh member 5 on the inner surface side of the mold 3, and the other configurations are the mold of the first embodiment shown in FIGS. 1 to 4. It is almost the same as the manufacturing equipment.

  As shown in FIG. 5, the mold manufacturing apparatus that does not include the mesh member 5 first forms a cavity 1 therein, and drills an infinite number of air holes 2 having a diameter smaller than the average particle diameter of the coated sand 4. The coated mold 3, the coated sand supply unit 6 for supplying the coated sand 4 into the cavity 1, and the superheated steam 7 as a gas in the cavity 1 from the periphery of the mold 3 through the vent hole 22 of the mold 3. Is provided with a superheated steam supply section (gas supply section) 8 that supplies the superheated steam and a superheated steam discharge section (gas discharge section) 9 that discharges the superheated steam 7 from the cavity 1.

  As can be seen by removing the mesh member 5 from FIG. 2, the mold 3 is composed of a pair of split molds 31, 32. By connecting the split molds 31, 32, a cylindrical cavity 1 is formed inside. Is formed. Each of the split dies 31, 32 includes a bottomed semi-cylindrical mold body 31a, 32a and box-shaped frame parts 31b, 32b integrally formed in a box shape on the back side of the mold body 31a, 32a. And back plates 33 and 34 for closing the back side openings of the box-shaped frame portions 31b and 32b, and innumerable vent holes 22 are formed in the bottomed semi-cylindrical mold body portions 31a and 32a. Has been. The ventilation hole 22 is drilled by a laser processing machine for drilling so as to penetrate the inner and outer surfaces of the mold main body portions 31a and 32a linearly. Depending on the configuration of the superheated steam supply unit 8, the vent hole 22 may be provided not only on the side surface side of the cavity 1 but also on the upper surface side, or the superheated steam 7 may be supplied from the lower surface side.

  The hole diameter of the air holes 22 is smaller than the average particle diameter of the coated sand 4 and is, for example, 0.2 mm (200 μm). That is, the average particle diameter of the coated sand 4 is about 400 to 600 μm for a coarse one and about 250 to 350 μm for a fine one. If the hole diameter of the air hole 22 is 0.2 mm (200 μm), the coated sand 4 Smaller than the average particle size. The vent hole 22 is usually a round hole having a circular cross section, but may be a slit. Therefore, in the case of a round hole, the inner diameter is formed smaller than the average particle diameter of the coated sand 4, but in the case of a slit, the slit width may be formed smaller than the average particle diameter of the coated sand 4.

  Production of a mold by using the mold production apparatus will be described with reference to FIGS. 6 and 7. First, as shown in FIG. 6, the coated sand supply unit 6 is connected to the sand supply port 10 of the mold 3. When the shutter 62 is opened in this state, the coated sand 4 in the hopper 61 is supplied into the cavity 1 of the mold 3 through the sand supply port 10. When the supply of the coated sand 4 into the cavity 1 is completed, as shown in FIG. 7, the coated sand supply unit 6 is separated from the sand supply port 10 of the mold 3 and the sand supply port 10 is closed, for example. 19, the valve 15 of the superheated steam supply unit 8 is opened to supply the superheated steam 7 into the cavity 1. When the superheated steam 7 is supplied from the superheated steam supply unit 8, the superheated steam 7 supplied into the cavity 1 is activated by operating the suction pump 16 of the superheated steam discharge unit 9. The particles pass through the particles and are forcibly discharged from the vent hole 22 for discharging the superheated steam at the bottom of the mold 3.

  In this case, the superheated steam 7 is supplied from the superheated steam generator 12 to the superheated steam introduction part 13 through the superheated steam pipe part 14. Since the superheated steam introducing portion 13 is provided along the outer periphery of the mold 3, the superheated steam 7 supplied into the superheated steam introducing portion 13 is molded with an infinite number of vent holes 22. The entire outer periphery of the mold 3 is covered, passes uniformly through the air holes 22 of the mold 3, flows into the cavity 1, and reaches every corner of the coated sand 4 supplied into the cavity 1. The entire coated sand 4 can be heated uniformly.

  As described above, according to this mold manufacturing apparatus, an infinite number of air holes 22 having a hole diameter smaller than the average particle diameter of the coated sand 4 are formed in the mold 3 in which the cavity 1 is formed. 3, the coated sand 4 in the cavity 1 is heated by supplying it into the cavity 1 through the vent hole 22 from around the periphery of the pipe 3, so that the coated sand 4 in the cavity 1 enters the vent hole 22 and enters the vent hole 22. Without blocking the inflow, the superheated steam 7 from the periphery of the mold 3 can be caused to flow into the cavity 1 through the vent hole 22 and be spread over the coated sand 4 in the cavity 1. The coated sand 4 can be heated uniformly to produce a homogeneous mold. Further, since the superheated steam 7 has a remarkably large heat capacity as compared with high-temperature air or saturated steam at the same temperature, the entire coated sand 4 in the cavity 1 can be instantaneously heated to cure the binder, and the shortness is short. The mold can be manufactured in time.

  Further, the vent hole 22 of the mold 3 can be a round hole or a slit, which is mechanically drilled by a laser processing machine, for example, and penetrates both the inner and outer surfaces of the mold 3 straight. And since the inner surface is smooth, the circulation of the superheated steam 7 is smooth, and the hole cleaning becomes easy. At this time, the wall thickness between the outer peripheral surface of the mold main body portions 31a and 32a constituting the split molds 31 and 32 of the mold 3 (the surface constituting the superheated steam introducing portion 13) and the inner peripheral surface of the cavity 1 is 20 mm or less. In this case, drilling with a laser can be performed stably and controlled. The wall thickness is 20 mm or less, preferably 10 mm or less, more preferably 6 mm or less. Further, by making the inner diameter of the air hole 22 200 μm or less, air is passed without reliably passing the coated sand particles, and since the hole diameter is small, the casting surface is deteriorated by the superheated steam 7 blown from the air hole 22. A mold having a good appearance can be formed while being suppressed. For example, if the vent hole 22 is a hole formed in a porous material made of, for example, a sintered metal, the hole is not linear, but is complicatedly wound, or the inner surface of the hole is uneven. Therefore, the circulation of superheated steam is poor and the hole cannot be cleaned. In addition, when the mold is formed of a porous material made of sintered metal, a mold for making the mold is necessary, and the manufacturing cost is very high.

DESCRIPTION OF SYMBOLS 1 Cavity 2 Ventilation hole 3 Mold 4 Coated sand 5 Mesh member 6 Coated sand supply part 7 Superheated steam (gas)
8 Superheated steam supply unit (gas supply unit)
9 Superheated steam discharge section (gas discharge section)
10 Sand supply port 13 Superheated steam introduction part (gas introduction part)
22 Vent

Claims (10)

A mold that forms a cavity inside and has numerous air holes,
A mesh member that is stretched over the entire inner surface of the mold excluding the sand supply port side and allows air to pass but does not allow coated sand particles to pass through.
A coated sand supply unit for supplying the coated sand into the cavity;
A gas supply unit for supplying gas into the cavity from the periphery of the mold through the ventilation holes and mesh members of the mold;
An apparatus for producing a mold, comprising: a gas discharge unit that discharges gas from the cavity.   2. The mold manufacturing apparatus according to claim 1, wherein a hole diameter of the ventilation hole of the molding die is larger than an average particle diameter of the coated sand.   The mold manufacturing apparatus according to claim 1, wherein the mesh member has an opening of 200 μm or less.   The mold according to any one of claims 1 to 3, wherein the ratio of the total area of the vent holes to the area of the inner peripheral surface of the cavity is in the range of 100: 0.01 to 100: 10. Manufacturing equipment.   The said gas supply part contains the gas introducing | transducing part provided along the outer periphery of a shaping | molding die, The manufacturing apparatus of the casting mold in any one of Claims 1-4 characterized by the above-mentioned.   The mold manufacturing apparatus according to claim 5, wherein the gas supply unit includes pressure adjusting means.   The mold manufacturing apparatus according to any one of claims 1 to 6, further comprising suction means for sucking the gas discharged to the gas discharge section.   The mold manufacturing apparatus according to any one of claims 1 to 7, wherein the mold is removed by gas pressure.   The gas is at least one selected from amines, esters, carbon dioxide, water vapor, superheated water vapor, air, heated air, inert gas, and heated inert gas. The mold manufacturing apparatus according to any one of the above. 10. The mold manufacturing apparatus according to claim 1, wherein the coated sand binder is a phenol resin, a urethane resin, a saccharide, a protein, water glass, or an inorganic salt.

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