JP4150945B2 - Mold outer frame and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mold outer frame for holding a mold having a molding cavity mold surface for molding a molded product such as a die-cast product or a resin molded product, and a method for manufacturing the same.
[0002]
[Prior art]
Conventionally, in the molding field such as die casting and injection molding, as shown in FIG. 10, a mold outer frame 100 having a concave storage chamber 102 is provided. In the mold outer frame 100, a mold 200 having a molding cavity mold surface 202 for molding a molded product is inserted into the storage chamber 102 as a nested mold, and is fastened and held by a mounting bolt (not shown). A flat mold holding surface 104 that receives the mold 200 is formed on the bottom side of the housing chamber 102 of the mold outer frame 100. The mold holding surface 104 is applied to the mold back surface 204 facing away from the molding cavity mold surface 202 of the mold 200.
[0003]
When the mold outer frame 100 is used, a molding material such as a molten metal or a resin is injected into a molding cavity 300 configured by clamping the mold outer frame 100. Thereby, a molded product such as a cast product or a resin molded product is formed. After molding, the mold outer frame 100 is opened and the molded product is taken out.
[0004]
[Problems to be solved by the invention]
In the mold outer frame 100 described above, a pressure load such as a mold clamping force or a molding pressure acts on the mold 200 during use. Generally, the clamping force and the molding pressure are large. The mold clamping force may be several thousand tons, for example. The molding pressure is large in the case of injection molding, for example, 600-1500 kgf / cm. ² Sometimes it becomes.
[0005]
Since such a large pressure load acts on the mold outer frame 100, when the mold outer frame 100 is used for a long period of time, the mold holding surface 104 that divides the storage chamber 102 may be set. When settling occurs, the mold alignment accuracy of the mold outer frame 100 decreases, the dimensional accuracy of the molded product decreases, or a molding material such as molten metal leaks from the mold alignment surface during molding. The problem occurs.
[0006]
The present invention has been made in view of the above-described circumstances, and provides a mold outer frame that is advantageous in suppressing the occurrence of settling on a mold holding surface that partitions a storage chamber that holds a mold, and a method for manufacturing the same. The issue is to provide.
[0007]
[Means for Solving the Problems]
The mold outer frame according to the present invention is a mold outer frame in which a concave storage chamber in which a mold having a molding cavity mold surface for molding a molded product is inserted and held is opened on the surface,
The outer frame body,
It has a mold holding surface that is cast in the outer frame main body and the mold back surface facing the mold cavity surface of the mold is applied, and is composed of a core that is harder than the outer frame main body. It is a feature.
[0008]
According to the mold outer frame of the present invention, the mold holding surface of the core that is harder than the outer frame main body is applied to the mold back surface facing away from the molding cavity mold surface of the mold. For this reason, when a large pressure load acts on the mold during use of the mold outer frame, the pressure load is received by the hard core.
[0009]
A method for manufacturing a mold outer frame according to the present invention is a method for manufacturing the above-described mold outer frame, which includes a mold forming step for forming a fire-resistant mold in which a core is held in a casting cavity, and a core And a heating process for heating the mold to a temperature range of 200 to 600 ° C., a casting process for forming a solidified body by casting the core by casting and solidifying the molten metal in the casting cavity of the mold in the heated state, and solidification The body is finished to form an outer frame main body, and a finishing process for forming a mold outer frame having a core harder than the outer frame main body is sequentially performed.
[0010]
According to the mold outer frame manufacturing method of the present invention, the mold is heated to a temperature range of 200 to 600 ° C. together with the core, so that when the hot molten metal contacts the core, excessive quenching of the molten metal is suppressed. It is done. As a result, the integrity and bonding strength at the boundary surface between the solidified body that casts the core and the core are increased, and the retention of the core is improved.
[0011]
According to the mold outer frame manufactured by the manufacturing method according to the present invention, when a pressure load acts on the mold held by the mold outer frame when using the mold outer frame, the pressure load is It is received by a hard core.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
According to a preferred embodiment of the present invention, it is possible to adopt a configuration in which the projected area of the core plate is larger than the projected area of the mold. In this case, even when a large pressure load is applied to the mold held by the mold outer frame when the mold outer frame is used, the core is a hard core and excellent in surface pressure strength. The pressure load per unit area acting on the outer frame of the mold from the core plate is reduced by the stress dispersion, which is more effective in suppressing settling.
[0013]
The core is harder than the outer frame body. The term “hard” means that the average hardness of the core is higher than the average hardness of the outer frame main body. The average hardness of the core can be Vickers hardness, and the upper limit value can be any one of 350, 400, 450, 500, and the lower limit value can be any one of 200, 250, 300, 350, for example. Accordingly, the average hardness of the core can be about 200 to 500, preferably about 250 to 450 in terms of Vickers hardness. However, it is not limited to this. The load used for measuring the Vickers hardness is 20 kgf.
[0014]
The average hardness of the outer frame body is Vickers hardness, and the upper limit value can be any one of 200, 250, 300, and 350, and the lower limit value can be any one of, for example, 120, 200, 250, and 300. Therefore, the average hardness of the outer frame main body is Vickers hardness, which can be about 120 to 350, preferably about 140 to 300. However, it is not limited to this.
[0015]
In general, in a metal material such as an iron-based material, when the hardness is high, the tensile strength and the surface pressure strength tend to increase accordingly.
[0016]
Both the outer frame main body and the core board are preferably made of a metal material such as iron. The outer frame body can be formed of cast steel or cast iron. Typical cast iron includes spheroidal graphite cast iron and flake graphite cast iron. As described above, the average hardness of the core is harder than the average hardness of the outer frame body. In this case, the core may be hardened by quenching, may be hardened by carbide formation, or an intermetallic compound (for example, an intermetallic compound of Ni and Ti, an intermetallic compound of Ni and Al). It may be precipitation hardened by precipitating.
[0017]
In addition, the hardening form of a core board is not limited to this. When the core is cured by quenching, quenching and tempering can be performed as necessary.
[0018]
The core according to the present invention preferably includes at least one of an alloy element having a high hardenability multiple, an alloy element that generates carbide, and an alloy element that undergoes precipitation hardening. Examples of the alloy element having a high hardenability multiple include at least one of Si, Cr, Mo, W, and V in addition to carbon. In this case, the core can be easily baked, the core can be increased in hardness, and it is effective in suppressing settling. Examples of alloy elements that generate carbides include at least one of carbon, Cr, W, Mo, V, and Nb. Examples of alloy elements to be precipitation hardened include at least one of Cr, Ni, Al, Ti, Be, and Mo.
[0019]
In the core according to the present invention, although the carbon content varies depending on the cured form of the core, etc., when the core is 100%, the upper limit value of carbon is 0.5% in terms of weight ratio in the core. 0.8%, 1.0%, 1.2%, and 2.0%, and the lower limit can be 0.2%, 0.4%, and 0.6%. Therefore, the carbon content in the core can be set to, for example, 0.2 to 2.0%, 0.4 to 1.2%, or 0.4 to 0.8% by weight. However, it is not limited to these.
[0020]
The core board according to the present invention can be constructed by cutting a board material into a predetermined size. The core can be made of high alloy steel such as stainless steel, heat resistant steel, tool steel. The stainless steel may be any of martensitic stainless steel, austenitic stainless steel, ferritic stainless steel, PH stainless steel, maraging stainless steel, and the like. Examples of the high alloy steel other than stainless steel include tool steel such as tool steel for hot working, high speed steel, and spring steel.
[0021]
In view of the above circumstances, when the core is iron-based, the metal structure of the core can be composed of at least one of martensite, troostite, sorbite, austenite, and pearlite.
[0022]
According to the method of the present invention, in the mold forming step, a fire-resistant mold in which the core is held in the casting cavity is formed. In this case, the core plate may be incorporated into the mold after the mold is formed, or the mold may be molded while the core plate is incorporated.
[0023]
A sand mold can be adopted as the mold. In this case, sand such as silica sand as a skeleton can be used and hardened with a binder. In view of the temperature in the heating step, the binder is preferably an inorganic binder, particularly an inorganic binder having heat resistance. For example, a water glass binder can be employed. Assuming that the mold without the core is 100%, the ratio of the binder can be, for example, 2 to 15% by weight, but is not limited thereto. Note that the mold may be formed of bricks having high fire resistance.
[0024]
In the heating step according to the method of the present invention, the mold is heated to a temperature range of 200 to 600 ° C. together with the core plate. In this case, the entire mold in which the core plate is incorporated may be charged in the heating chamber of the heating furnace and heated, or the mold may be heated with a flame burner or the like. If the heating temperature of the core plate is too low, when the molten metal touches the core plate, the molten metal at that portion is excessively cooled, so that the bonding strength between the core plate and the outer frame body decreases. When the heating temperature of the core plate is too high, an oxide scale is generated on the core plate or the core plate is deformed. Considering such circumstances, the temperature of the mold is set to 200 to 600 ° C. When the core is a high alloy steel such as stainless steel, excessive generation of oxide scale is suppressed even when the core is heated to a high temperature. Note that the heating step may be performed in an air atmosphere, or may be performed in a reduced pressure atmosphere to suppress oxide scale, or may be performed in a reducing atmosphere.
[0025]
Although the heating temperature according to the method of the present invention differs depending on the material of the core, the material of the mold, the weight of the molten metal to be cast to form the outer frame body, the upper limit of the heating temperature is, for example, 600, 580 ° C, 550 ° C., 520 ° C., 490 ° C., 460 ° C., 430 ° C., 410 ° C., 380 ° C. For example, the lower limit value can be 200 ° C., 220 ° C., 250 ° C., 280 ° C., 310 ° C., 340 ° C., 370 ° C., 400 ° C., 430 ° C., or 460 ° C. Accordingly, the heating temperature can be 200 to 600 ° C, 220 to 580 ° C, 250 to 550 ° C, and 300 to 500 ° C. The heating time is affected by the size of the core plate and the outer frame body, the heating temperature, and the like, but in general, it can be about 2 to 12 hours, particularly about 3 to 8 hours.
[0026]
In the casting process according to the present invention, a solidified body in which the core is cast is formed by casting and solidifying the molten metal in the casting cavity of the mold in the heated state. Since the mold is in a heated state, the molten metal is good, and the contact surface between the core plate and the solidified body is melt-bonded so that both can be brought into close contact with each other.
[0027]
In the finishing process according to the present invention, the solidified body is finished into a mold outer frame. Thereby, a mold outer frame is formed. The mold outer frame includes an outer frame main body and a core that is cast in the outer frame main body and is harder than the outer frame main body. The core plate includes a mold holding surface applied to the mold back surface facing away from the mold cavity mold surface of the mold.
[0028]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
[0029]
As shown in FIG. 1, the 1st metal mold | die outer frame 1 which concerns on a present Example is attached to the die base 2, and comprises the movable side. The first mold outer frame 1 includes a rectangular outer frame body 3 formed of cast steel or spheroidal graphite cast iron, and a substantially rectangular flat plate core 4 formed of rolled steel. Yes.
[0030]
As shown in FIG. 1, the core 4 is integrally cast and embedded in the outer frame body 3, and both are in close contact with each other. The core 4 is set to have a higher average hardness than the outer frame body 3. Therefore, the core 4 is harder than the outer frame body 3. The average hardness of the outer frame body 3 is about 150 to 200 in terms of Vickers hardness. The average hardness of the core 4 is higher than the hardness of the outer frame body 3, and is about 300 to 380 in terms of Vickers hardness.
[0031]
Since the core 4 contains a large amount of alloying elements as described above, it has high hardness even if the cooling rate is slow. The core 4 may be hardened by quench hardening, may be hardened by the formation of carbides, or may be hardened by precipitation hardening.
[0032]
As shown in FIG. 4, a housing chamber 6 having an opening 6 a communicating with the outside air is formed at the center of the outer frame body 3. The storage chamber 6 has a machined (cut) inner wall surface 6c. The storage chamber 6 is a space in which a mold 7 having a molding cavity mold surface 70 for molding a molded product is inserted and held as a nested mold. As shown in FIG. 5, a flat mold back surface 73 is formed on the mold 7 on the side facing away from the mold cavity mold surface 70.
[0033]
As shown in FIG. 4, the periphery of the core plate 4 is cast into the outer frame body 3. The core plate 4 includes a flat mold holding surface 35 applied to the mold back surface 73 of the mold 7. The mold holding surface 35 is exposed to the storage chamber 6 and forms the bottom surface of the storage chamber 6. The projected area of the core plate 4 is set larger than the projected area of the mold 7. Therefore, in the plan view, as shown in FIG. 2 which is a plan view, projecting edges 45 are formed on the four sides of the core 4 so as to project substantially evenly from the outer surface 7 p of the mold 7. The four corners of the core plate 4 are formed with oblique sides 45 i at the four corners of the protruding edge 45. In FIG. 2, a hatched area indicates a molding cavity mold surface 70 for molding a molded product, and 39a and 39b indicate flow paths through which the molding material flows.
[0034]
The size of the core plate 4 is about 52 cm × 55 cm × 6 cm. The size of the outer frame body 3 is about 60 cm × 71 cm × 34 cm. The size is not limited to this, and can be appropriately changed according to the type of the molded product.
[0035]
The material of the core 4 is martensitic stainless steel, has high hardness, and is excellent in corrosion resistance such as normal temperature corrosion resistance and high temperature corrosion resistance.
[0036]
When manufacturing the 1st metal mold | die outer frame 1 which concerns on a present Example, it carries out as follows. First, in the mold forming step, as shown in FIG. 6, a mold 8 having fire resistance is formed. The mold 8 includes a lower mold 81, a middle mold 82 placed on the lower mold 81, and an upper mold 83 placed on the middle mold 82. The lower mold 81 includes a lower sand mold 81a formed of sand containing a binder and a casting frame 81c that holds the lower sand mold 81a. The middle mold 82 includes a middle sand mold 82a formed of sand containing a binder and an intermediate casting frame 82c that holds the middle sand mold 82a. The upper mold 83 includes an upper sand mold 83a formed of sand containing a binder and an upper casting frame 83c that holds the upper sand mold 83a.
[0037]
As shown in FIG. 6, the mold 8 is formed with a sprue cavity 85, a runner cavity 86, a weir cavity 87, and a feeder cavity 88, and a casting cavity 89 for molding a mold outer frame. Is formed. Since the weir cavity 87 is formed in the boundary area between the lower mold 81 and the middle mold 82, the molten metal is poured into the casting cavity 89 from the bottom side. As shown in FIG. 6, the feeder cavity 88 is located above the outer edge of the core plate 4. For this reason, the weight of the molten metal injected into the hot metal cavity 88 can act on the outer edge of the core 4.
[0038]
As shown in FIG. 6, the core 4 is supported by a plurality of holding bars 90 in a state where the one surface 4 b of the core 4 is placed horizontally on the upper surface of the bulging portion 82 k that is a part of the middle sand mold 82 a of the middle mold 82. Hold. Usually, the holding rod 90 may be about a bolt. As a result, the core 4 is held in a part of the casting cavity 89 of the mold 8. In this state, as shown in FIG. 6, the core plate 4 is in face-to-face contact with the bulging portion 82 k that is a part of the middle sand mold 82 a of the middle mold 82. Further, as shown in FIG. 6, the one surface 4 a and the peripheral surface 4 c of the core plate 4 are exposed in the casting cavity 89. The outer edge 4 e of the other side 4 b of the core 4 is also exposed in the casting cavity 89.
[0039]
Next, a heating process is performed. In the heating step, the mold 8 holding the core plate 4 is accommodated in the heating chamber 802 of the heating furnace 800, and the mold 8 is heated together with the core plate 4 to a predetermined temperature range of 200 to 600 ° C. . The heating time varies depending on the heating temperature, but can be, for example, about 3 to 8 hours. As a result, the core 4 is heated together with the mold 8 to a high temperature state. Note that the heating chamber 802 is an air atmosphere. Since the core 4 contains a large amount of an alloy element such as Cr having excellent oxidation resistance, the oxide scale in the core 4 can be suppressed.
[0040]
Next, a casting process is performed. In the casting step, a high-temperature iron-based melt of about 1380 to 1420 ° C. is cast into the casting cavity 89 of the heated mold 8 immediately after being taken out from the heating furnace 800. By solidifying the molten metal in the casting cavity 89, the outer surface of the core 4 is cast. Thereby, the iron-based solidified body M shown in FIG. 3 is formed. Specifically, as shown in FIG. 3, the solidified body M casts the entire region of the one surface 4 a of the core plate 4, the entire region of the peripheral surface 4 c of the core plate 4, and the outer edge portion 4 e of the single surface 4 b of the core plate 4.
[0041]
Since the outermost surface of the core 4 in contact with the iron-based molten metal melts and re-solidifies, the adhesion between the outer frame body 3 and the core 4 is improved. Further, since the shrinkage accompanying solidification and the shrinkage accompanying cooling after solidification act on the solidified body M, the adhesion between the outer frame main body 3 and the core 4 formed of the solidified body M by these shrinkage. Has improved.
[0042]
In the casting step described above, the molten metal can be poured into the casting cavity 89 of the mold 8 while the mold 8 provided with the core plate 4 is held in the heating furnace 800.
[0043]
According to the present embodiment, the mold is heated together with the core plate 4 to a predetermined temperature range of 200 to 600 ° C., so even if the molten metal poured in the casting process contacts the core plate 4, the molten metal is excessive. At the same time, the core 4 is prevented from cracking. As a result, the integrity and the bonding strength at the boundary surface between the solidified body M that casts the core 4 and the core 4 are increased. Welding at the boundary surface between the solidified body M and the core 4 or alloying by welding can also be achieved. In this case, since the bonding strength at the boundary surface between the solidified body M and the core plate 4 is further increased, the holding ability of the outer frame body 3 formed of the solidified body M to hold the core plate 4 is improved. When the casting process is completed, the mold 8 is collapsed, and the solidified body M in which the core plate 4 is embedded is taken out as shown in FIG. In this state, as shown in FIG. 3, most of the central region of the one surface 4 b of the core plate 4 is exposed to the storage chamber 6 and is in a naked state.
[0044]
Next, a heat treatment step is performed. In the heat treatment step, the entire first mold outer frame 1 is loaded by inserting the first mold outer frame 1 into a heating furnace (the heating furnace 800 described above or another heating furnace may be used). The core 4 is heated to a predetermined heat treatment temperature region (for example, 850 to 950 ° C.). Thereafter, a cooling medium (for example, air for cooling, mist, water, oil, or the like in some cases) is sprayed on the first mold outer frame 1 to promote cooling of the core 4, whereby the first mold outer frame 1 is cooled at a predetermined cooling rate. As a result, heat treatment (quenching or normalizing) is performed on the core plate 4.
[0045]
In the present embodiment, as can be understood from FIG. 3, the core plate 4 is embedded in the solidified body M serving as the outer frame main body 3, but as described above, most of the central region of the one surface 4 b of the core plate 4 is formed. It is exposed to the storage chamber 6 and is in a naked state. For this reason, during the heat treatment described above, a cooling medium (for example, air for cooling, mist, water, oil, or the like in some cases) is supplied to the storage chamber 6 to forcibly or naturally be applied to one side 4b of the core 4. If contact is made, the cooling rate of the core plate 4 can be increased. Therefore, the heat treatment property (hardenability or normalizing property) of the core plate 4 can be effectively ensured, which is advantageous for ensuring the required hardness of the core plate 4 and increases the hardness of the core plate 4. It will be advantageous. Mist is a mist-like cooling medium sprayed with cooling water.
[0046]
As can be understood from the comparison between FIGS. 3 and 5 in particular, the single side 4b of the core 4 is the side on which the mold 7 comes into contact. It is advantageous to suppress
[0047]
Depending on the composition of the core 4, a cooling medium (for example, air for cooling, mist, water, oil, etc. in some cases) may not be forcibly fed to the housing chamber 6, but simply left to cool the core 4. It may be in the form of just letting it. When burning cracks or the like occur in the core plate 4, it is preferable to use air, mist, oil or the like having a cooling capacity lower than that of water.
[0048]
In this embodiment, when the above-described heat treatment is quenching of the core 4, tempering such as high temperature tempering or low temperature tempering can be performed on the core 4 as necessary. If the core 4 is tempered, the toughness of the core 4 can be increased while maintaining the required hardness of the core 4. In this case, the solidified body M in which the core plate 4 is embedded can be charged into a heating furnace and heated and held at a tempering temperature (for example, 500 to 600 ° C. in the case of high temperature tempering). . If not necessary, the tempering process may not be performed.
[0049]
Even if the core 4 having a high alloy element content is quenched, the solidified body M having a low alloy element content is not basically quenched.
[0050]
After finishing the heat treatment process as described above, a finishing process is performed next. In the finishing process, finishing is appropriately performed by machining (cutting). Specifically, as can be understood from FIG. 4, Δt cutting is performed on a portion of the one surface 4 b of the core plate 4 exposed to the storage chamber 6 by machining (cutting). As a result, a flat and smooth mold holding surface 35 is formed on the core plate 4. Since the mold holding surface 35 is flattened and smoothed by machining (cutting), the adhesion holding property of the mold 7 to the mold back surface 73 is improved. Moreover, the smooth inner wall surface 6c is formed in the outer frame main body 3 by the above-described machining (cutting).
[0051]
According to the present embodiment, as shown in FIG. 5, the mold 7 is inserted into the accommodation chamber 6 of the first mold outer frame 1 as an insert mold from the opening 6 a and is accommodated and held. In a state where the mold 7 is housed and held in the housing chamber 6 of the first mold outer frame 1, the flat mold back surface 73 of the mold 7 is applied to the flat mold holding surface 35 of the outer frame body 3. ing.
[0052]
Further, as can be understood from FIG. 5, in a state where the mold 7 is housed and held in the housing chamber 6 of the mold outer frame 1, a drilling tool such as a drill is used to attach the mounting hole from the back side of the first mold outer frame 1. 36 is formed. The mounting hole 36 includes a hole 36 a penetrating the outer frame body 3 in the thickness direction, a hole 36 b penetrating the core plate 4 in the thickness direction, and a hole 36 c having a female screw portion 37 formed on the back surface of the mold 7. Is formed. The holes 36a, 36b, 36c communicate with each other in series. 5, the die 7 is fixed to the housing chamber 6 of the outer frame body 3 in a detachable manner by screwing the male screw portion 86 on the distal end side of the mounting bolt 85 into the female screw portion 37.
[0053]
If the mounting bolt 85 is loosened, the mold 7 can be removed from the outer frame body 3. The number of the mounting bolts 85 can be appropriately selected according to the size of the core plate 1 or the mold 7, and can be 2 to 30 or 5 to 12, for example. However, it is not limited to this.
[0054]
As shown in FIG. 1, the 2nd metal mold | die frame 9 which is the other party of the 1st metal mold | die outer frame 1 is provided. The second mold outer frame 9 constitutes the fixed side. The second mold outer frame 9 has the same configuration as the first mold outer frame 1 and is manufactured by the same manufacturing method. That is, the second mold outer frame 9 is composed of the outer frame main body 3 and the hard core 4 cast into the outer frame main body 3.
[0055]
In use, as shown in FIG. 1, the first mold outer frame 1 and the second mold outer frame 9 are attached to a not-shown mold attaching device having mold clamping and mold opening functions. In this state, the die base 2 is equipped on the back side of the movable first mold outer frame 1. When the mold attaching device operates in the mold clamping direction, the first mold outer frame 1 and the second mold outer frame 9 are clamped as shown in FIG. When the first mold outer frame 1 and the second mold outer frame 9 are clamped, the molding cavity mold surface 70 of the first mold outer frame 1 and the molding cavity mold surface 70 of the second mold outer frame 9 are fixed. Thus, the molding cavity 75 is defined.
[0056]
A high-temperature molten metal (material: aluminum, temperature: 640-750 ° C.), which is a molding material, is injected into the molding cavity 75 at high speed by injection molding. When the mold attachment device operates in the mold opening direction after the molten metal has solidified, the first mold outer frame 1 and the second mold outer frame 9 are opened, and the molded product is formed by the pushing action of the unillustrated push pin. It is taken out.
[0057]
In use, a pressure load such as a clamping force or a molding pressure acts on the mold 7 held by the first mold outer frame 1. When a pressure load acts in this way, the pressure load is received by the hard core 4 through the mold 7. The core 4 has high hardness and high surface pressure strength. For this reason, even if the period of use is prolonged or the pressure load is large, the occurrence of settling on the mold holding surface 35 that defines the storage chamber 6 that holds the mold 7 is suppressed.
[0058]
In particular, in this embodiment, as shown in FIG. 2, since the projected area of the core 4 is set larger than the projected area of the mold 7, the core 4 receiving the pressure load from the mold 7 is used. The pressure receiving area has increased. Therefore, even if the service period is prolonged or the pressure load is excessive, the occurrence of settling on the mold holding surface 35 of the first mold outer frame 1 is suppressed.
[0059]
That is, in the present embodiment, as shown in FIG. 2, projecting edge portions 45 projecting from the outer surface 7 p of the mold 7 are formed on the four sides of the core plate 4. The load can be distributed, and the pressure load on the joint surface 3a of the outer frame body 3 with the core 4 can be reduced. Specifically, the pressure load on the joint surface 3a can be reduced to approximately 1 / area ratio. Therefore, even if the period of use is considerably prolonged or the pressure load is excessive, the mold holding surface 35 is damaged due to the settling of the joint surface 3a with the core 4 of the outer frame body 3. Occurrence is further suppressed.
[0060]
The core 4 is made of stainless steel and has excellent corrosion resistance. Therefore, corrosion on the mold holding surface 35 which is a boundary area between the core 4 and the mold 7 can be suppressed. Furthermore, wear due to corrosion can also be suppressed. For example, fretting wear can be prevented. In particular, even when cooling water or a mold release agent enters the mold holding surface 35 which is a boundary region between the mold 7 and the core plate 4, corrosion on the mold holding surface 35 can be suppressed. it can. For this reason, in the first mold outer frame 1 and the second mold outer frame 9, it is possible to prevent wear due to corrosion and promotion of settling due to a decrease in surface pressure strength due to corrosion. Similarly, the occurrence of settling on the mold holding surface 35 of the second mold outer frame 9 is suppressed.
[0061]
Further, in the present embodiment, when the molten metal that becomes the solidified body M is cast in the casting process, the mold 8 is heated in advance. Furthermore, since the core 4 is heated to a high temperature in the casting process, even if the hot molten metal touches the core 4, excessive quenching of the molten metal can be suppressed. For this reason, the joint strength in the boundary region between the outer frame main body 3 and the core plate 4 can be increased. Alloying in the boundary region between the outer frame main body 3 and the core plate 4 can also be expected.
[0062]
(Test example)
FIG. 7 shows test results for testing the relationship between the heating temperature of the mold 8 and the bonding strength between the outer frame body 3 and the core plate 4. In this test, a model in which the outer frame body 3 and the core plate 4 were reduced was used. The main component of the mold 8 was silica sand, the binder was water glass, the material of the core 4 was martensitic stainless steel (SUS420J2), and the material of the outer frame body 3 was SCMn3A. The horizontal axis in FIG. 7 indicates the heating temperature of the mold, and the vertical axis in FIG. 7 indicates the bonding strength in the boundary region between the outer frame body 3 and the core plate 4. The bonding strength was measured by conducting a tensile test on the above model and applying a tensile stress in a direction perpendicular to the boundary surface.
[0063]
In FIG. 7, the casting strength of the outer frame body 3 is shown as S1, 80% of the casting strength of the outer frame body 3 is shown as S2, and 70% of the casting strength of the outer frame body 3 is shown as S3. As shown in FIG. 7, the bonding strength was high when the heating temperature of the mold 8 was 200 to 600 ° C., and about 70% of the casting strength of the outer frame body 3 was obtained. In particular, when the heating temperature of the mold 8 is 300 to 500 ° C., about 80% of the casting strength of the outer frame body 3 was obtained. In particular, the bonding strength was highest at 400 ° C.
[0064]
(Other examples)
As shown in FIG. 8, recesses 4 x and 4 y may be formed in the core plate 4. Since the molten metal constituting the outer frame main body 3 enters and solidifies into the recesses 4x and 4y, the degree of mechanical engagement between the core plate 4 and the outer frame main body 3 can be improved.
[0065]
As shown in FIG. 9, the reinforcing rib 4 w can be formed on the surface of the core plate 4 opposite to the mold 7. Not only can the core 4 itself be reinforced by the reinforcing ribs 4w, but the molten metal constituting the outer frame main body 3 casts the reinforcing ribs 4w, so that the degree of mechanical engagement between the core 4 and the outer frame main body 3 can be improved.
[0066]
In the embodiment described above, one core plate 4 is embedded in the mold outer frames 1, 9. However, the present invention is not limited to this, and a mold is formed by stacking a plurality of core plates 4 such as two. It can also be embedded in the outer frames 1 and 9.
[0067]
In addition, the present invention is not limited only to the above-described embodiments, and can be appropriately changed as necessary without departing from the scope of the invention.
[0068]
(Appendix)
The following technical idea can also be grasped from the above description.
(1) A mold according to each claim, wherein the central region of the core is exposed to a storage chamber for storing and holding the mold, and the periphery of the core is cast into an outer frame body. Outer frame.
(2) The mold outer frame according to each claim, wherein the mold holding surface is machined (cut) and is flattened. Since the mold holding surface is flattened, the tightness holding property of the nested mold is improved.
(3) In the claim relating to the manufacturing method, the heating step accommodates the entire mold holding the core plate in a heating chamber of a heating furnace, and heats both the core plate and the mold. Manufacturing method.
(4) In the claim relating to the manufacturing method, a heat treatment step is performed between the casting step and the finishing step, and the heat treatment step is performed in a state in which a portion of the core cast into the solidified body is exposed to the storage chamber. This is performed by bringing a cooling medium (for example, air, wind, mist, water, oil, etc.) into contact with the exposed portion of the core plate, thereby promoting the cooling of the core plate and increasing the cooling rate of the core plate. Manufacturing method of outer frame. Even when the core is cast into the solidified body, cooling of the core can be promoted, which is advantageous for ensuring the required hardness of the core.
(5) A mold forming process for forming a fire-resistant mold having a core held in a casting cavity;
A heating process for heating the mold together with the core, a casting process for forming a solidified body by casting the core into the casting cavity of the mold in a heated state, and solidifying the core, and casting into the solidified body. In a state where a part of the core is exposed to the outside air (containment chamber), a cooling medium (for example, air, wind, mist, water, oil, etc.) is brought into contact with the exposed part of the core to promote cooling of the core. A heat treatment step and a solidification body that has undergone the heat treatment step are finished to form an outer frame body, and a finishing step is performed in order to form a mold outer frame having the core harder than the outer frame body. A method for manufacturing a mold outer frame.
[0069]
Even when the core is cast into the solidified body, cooling of the core can be promoted, which is advantageous for ensuring the required hardness of the core.
[0070]
【The invention's effect】
According to the mold outer frame of the present invention, even when an excessive pressure load acts on the mold held by the mold outer frame when the mold outer frame is used, the pressure load is hard. It is received by the core board. For this reason, even if a mold outer frame is used over a long period of time, it is possible to suppress the occurrence of settling on the mold holding surface that divides the storage chamber that holds the mold.
[0071]
According to the method of the present invention, it is possible to manufacture a mold outer frame that has the effect of suppressing the above-described settling.
[0072]
According to the method of the present invention, the mold is heated to a temperature range of 200 to 600 ° C. together with the core plate, so that excessive rapid cooling when the molten metal contacts the core plate can be suppressed. As a result, the integrity of the boundary surface between the solidified body that casts the core and the core increases, and the retainability of the core improves.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a state where a first mold outer frame and a second mold outer frame are clamped.
FIG. 2 is a plan view of a first mold outer frame.
FIG. 3 is a cross-sectional view of a first mold outer frame including an outer frame main body having a storage chamber.
FIG. 4 is a cross-sectional view of a first mold outer frame in a state in which a mold holding surface is formed on a core board.
FIG. 5 is a cross-sectional view of a state in which a mold is held in a housing chamber of an outer frame main body of a first mold outer frame.
FIG. 6 is a cross-sectional view showing a state where the core is held in a casting cavity of a mold.
FIG. 7 is a graph showing test results of tests on the relationship between the heating temperature of the mold and the bonding strength between the outer frame carrier and the core.
FIG. 8 is a cross-sectional view showing a state in which the mold is held in the housing chamber of the outer frame main body of the first mold outer frame according to another embodiment.
FIG. 9 is a rear view of the core board according to another embodiment.
FIG. 10 is a cross-sectional view showing a state in which the first mold outer frame and the second mold outer frame are clamped according to the related art.
[Explanation of symbols]
In the figure, 1 is a first mold outer frame, 3 is an outer frame main body, 35 is a mold holding surface, 4 is a core, 6 is a storage chamber, 7 is a mold, 70 is a mold cavity mold surface, and 73 is a mold. The mold back surface, 8 is a mold, 9 is a second mold outer frame, and M is a solidified body.

Claims (4)

A mold outer frame in which a concave storage chamber in which a mold having a mold cavity mold surface for molding a molded product is inserted and held is opened on the surface,
The outer frame body,
The outer frame main body includes a mold holding surface that is cast into the outer frame main body and to which a mold rear surface facing the molding cavity mold surface of the mold is applied, and includes a core that is harder than the outer frame main body. A mold outer frame characterized by 2. The mold outer frame according to claim 1, wherein a projected area of the core plate is larger than a projected area of the mold. 3. The mold outer frame according to claim 1, wherein the core plate is made of stainless steel. A mold forming process for forming a fire-resistant mold with a core held in a casting cavity;
A heating step of heating the mold together with the core plate to a temperature range of 200 to 600 ° C .;
A casting step of forming a solidified body by casting the core plate by casting and solidifying a molten metal into a casting cavity of the mold in a heated state;
Finishing the solidified body as an outer frame main body, and sequentially performing a finishing step of forming a mold outer frame having the core harder than the outer frame main body. Production method.

Images