JP2016215266A - Manufacturing method of molding metal mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a molding metal mold and the molding metal mold excellent in machinability and strength at low cost.SOLUTION: A manufacturing method of a molding metal mold includes a process of pouring low melting point alloy material molten metal 10 into a casting mold frame 11 of the molding metal mold, a process of cooling the final solidification part of the molten metal at a cooling speed of a predetermined cooling speed or more on the whole outer periphery except for an upper surface or the whole outer periphery including the upper surface of the casting mold frame 11 filled with the low melting point alloy material molten metal and a process of press-pressurizing by taking out of the casting mold frame 11 at the predetermined solidification temperature when the molten metal is solidified. An automatic supply device 20 of a cooling fluid 16 comprises an upper surface opening type first tank body 12A capable of storing the casting mold frame 11 for pouring the molten metal and the cooling fluid 16 introduced-arranged on the outside of the casting mold frame 11, and also includes a second tank body 13 for storing the first tank body 12A and collecting the cooling fluid overflowing from the first tank body, a reflux mechanism 22 for recirculating the fluid in the second tank body 13 in the first tank body 12A and a fluid cooling device 24 provided in a reflux passage by the reflux mechanism 22.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for manufacturing a molding die and a molding die, and more particularly to a method for manufacturing a molding die using a low melting point alloy material excellent in machinability and a molding die.

  Metal molds for producing metal or synthetic resin parts by plastic working such as press working or injection molding are known, and alloyed steel materials are generally used. Recently, there has been a growing need for molds that have the strength and durability required for press processing, etc. while having good machinability and low cost in response to the need for shortening the product trend cycle and low volume production. Yes. Conventionally, Patent Document 1 suggests a press die using a low melting point alloy such as ZAS.

JP-A-5-195121

  Patent Document 1 proposes a zinc alloy mold in which the alloy component ratio of aluminum and copper is increased to improve the wear resistance against iron. However, in the metal mold of Patent Document 1, a large amount of alloy elements of aluminum and copper are added as materials to improve wear resistance, and the manufacturing cost is high. Moreover, in the metal mold | die of patent document 1, since alloy components, such as aluminum and copper, are mainly added, fluidity | liquidity falls easily by adding a large amount of components with high melting point and large specific gravity. For this reason, component segregation, reverse shrinkage, and internal shrinkage (shrinkage cavities inside the casting) are likely to occur, and the component design is complicated and takes time because these must be taken into consideration. Furthermore, the aluminum phase lighter than the zinc melt rises due to the addition of a large amount of aluminum. As a result, the solidification temperature rises in this part. In this regard, in the general-purpose ZAS alloy, solidification starts from the lower part, and the upper part becomes the final solidified part and is closed.) In order to prevent such a phenomenon, a top heat method is used in which the upper part of the casting is heated by a gas burner and the final solidified part is brought to the upper part. Grain refinement strengthening could not be expected, and there was a risk that the hardness would decrease.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a method for manufacturing a molding die having excellent machinability, strength and durability at a low cost and for molding. To provide molds.

  In order to solve the above problems, a method for manufacturing a molding die according to the present invention includes a step (S1) of pouring a low melting point alloy material molten metal into a mold frame of the molding die, and a low melting point alloy material molten metal. A step (S2, S3) of cooling the final solidified portion of the molten metal at a cooling rate equal to or higher than a predetermined cooling rate for the entire outer periphery other than the upper surface of the filled mold frame or the entire outer periphery including the upper surface; A step (S4) of taking out from the mold frame and press-pressing at a temperature.

  At that time, the cooling rate of the molten metal is preferably 0.8 ° C./s or more.

  Moreover, it is good for the raw material temperature at the time of pressurization of the solidified molten metal to be the temperature in the range of 50 degreeC +/- 5 degreeC.

  In addition, the entire mold frame to be poured is accommodated in an open or closed tank body, and the cooling fluid is automatically supplied to the tank body according to the material temperature of the molten metal by an automatic cooling fluid supply device. It is good to do by supplying.

  In addition, the cooling fluid automatic supply device 20 includes an open top first tank body 12A capable of accommodating a casting mold frame 11 for pouring and a cooling fluid 16 to be introduced and arranged outside the casting mold frame 11; The second tank body 13 that contains the first tank body 12A and collects the cooling fluid 16 that overflows from the first tank body, and the reflux that causes the fluid 162 in the second tank body 13 to flow back into the first tank body 12A. The mechanism 22 and the fluid cooling device 24 provided in the reflux path 22a by the reflux mechanism may be included.

  Furthermore, when the molten metal in the mold frame is cooled while supplying the coolant fluid to the outer periphery of the mold frame, the cooling position in the circumferential direction may be moved in layers from the bottom to the bottom.

  Further, the molding die according to the present invention is such that the low melting point alloy material molten metal 10 is poured into the mold frame 11 of the molding die and the entire outer periphery or top surface other than the top surface of the mold frame filled with the low melting point alloy material molten metal. When the final solidification part of the molten metal is cooled at a cooling rate of 0.8 ° C./s or more while cooling the entire outer periphery including the molten metal, the molten metal is solidified and the material temperature is within a range of 50 ° C. ± 5 ° C. It is constructed by being taken out from the mold frame 11 and manufactured by pressing.

In that case, it is preferable that the molding die satisfy a Brinell hardness of 151 or more and a tensile strength of 302 N / mm ² or more.

  According to the method for manufacturing a molding die of the present invention, a step of pouring a low melting point alloy material molten metal into the mold frame of the molding die, and the entire outer periphery other than the upper surface of the mold frame filled with the low melting point alloy material molten metal Or the process of cooling the final solidification part of the molten metal at a cooling rate equal to or higher than a predetermined cooling rate for the entire outer periphery including the upper surface, the process of taking out from the mold frame and press-pressing when the molten metal solidifies and has a predetermined solidification temperature, The general-purpose zinc-based alloy is a general-purpose zinc-based alloy that maintains good machinability at a low cost, and at the same time cools the entire circumference of the mold frame instead of cooling locally or in multiple dispersions. By doing so, the refinement | miniaturization part of the crystal grain of a molten material is formed in high density, and a structure | tissue can be strengthened and hardness and intensity | strength can be improved significantly.

  At that time, the cooling rate of the molten metal is 0.8 ° C./s or more, and the material temperature at the time of pressurization of the solidified molten metal is 50 ° C. ± 5 ° C. Although it is a zinc-based alloy, the hardness can be greatly improved, and the durability can be improved.

  In addition, the entire mold frame to be poured is accommodated in an open or closed tank body, and the cooling fluid is automatically supplied to the tank body according to the material temperature of the molten metal by an automatic cooling fluid supply device. Since it is performed by supplying, rapid cooling can be realized reliably by continuously supplying cooling refrigerant exceeding heat exchange with a high temperature of about 400 ° C.

  An automatic cooling fluid supply apparatus includes a first tank body having an open top surface capable of accommodating a mold frame for pouring, a cooling fluid introduced and disposed outside the mold frame, and a first tank body. A second tank body that collects the cooling fluid that overflows from the first tank body, a reflux mechanism that recirculates the fluid in the second tank body into the first tank body, and a fluid provided in a reflux path by the reflux mechanism. Therefore, rapid cooling can be realized reliably by continuously supplying a coolant for cooling the molten metal.

  When cooling the molten metal in the mold frame while supplying the coolant fluid to the outer periphery of the mold frame, the cooling position in the circumferential direction moves from bottom to top while cooling in layers, so the stacking position of the refrigerant is all around Since cooling is performed while rising at the same time, crystal grain refined portions are stacked and formed at a high density, and the structure can be strengthened to significantly improve the hardness and strength. At the same time, wear resistance is improved.

  Further, according to the molding die of the present invention, the low melting point alloy material molten metal is poured into the mold frame of the molding die, and the entire outer periphery or top surface other than the top surface of the mold frame filled with the low melting point alloy material molten metal is poured. The final solidification part of the molten metal is cooled at a cooling rate of 0.8 ° C./s or more while cooling the entire outer periphery, and the mold is solidified when the molten metal is solidified and the material temperature is in the range of 50 ° C. ± 5 ° C. Because it is a molding die that is produced by press-pressing it out of the frame, it is a general-purpose zinc-based alloy that can be dispersed locally or in multiple locations on the mold frame while maintaining good machinability at low cost. By cooling the entire circumference at the same time instead of cooling, the refined portion of the crystal grains of the molten material is formed at a high density. As a result, the structure can be strengthened and the hardness and strength can be greatly improved.

According to the molding die of the present invention, since the molding die is a molding die satisfying a Brinell hardness of 151 or more and a tensile strength of 302 N / mm ² or more, a commercially available ZAS. It is possible to maintain unprecedented high hardness and strength by a simple method using a material, and also to maintain durability.

It is a principle process explanatory drawing of the manufacturing method of the metal mold | die of this invention, (a) is explanatory drawing of the method of arrange | positioning and cooling the casting_mold | template poured in the tank in which one part was open | released, (b) The explanatory view of the method of arranging and cooling the poured mold in the closed tank, (c) is the figure explaining the pressurization process of the hardened material. FIG. 2 is an enlarged explanatory view of FIG. It is explanatory drawing of the cooling structure of the mold frame by the partially open tank of the method of this invention. The process of the metal mold | die manufacturing method in the case of using the partially open tub as embodiment of the method of this invention is demonstrated, Fig. (A) is explanatory drawing of the state which pours in a mold frame, (b) FIG. 4C is an explanatory diagram of a cooling process, FIG. 3C is an explanatory diagram of a state in which a cured material is inverted and placed on a press stand, and FIG. 4D is a diagram illustrating a state in which the cured material of FIG. It is. It is a flowchart figure of the principle process of the method of this invention. It is a figure which shows the characteristic test result of the Example of a metal mold | die manufactured using the method of this invention, and a comparative example.

  The present invention relates to a method of manufacturing a mold itself of a molding machine used for molding an article such as a press or injection molding, and a mold. Examples include a mold for press molding such as metal processing such as a die and a punch, and a mold for injection-filling and molding a thermoplastic resin at a high pressure.

  1 and 2 are explanatory views of the principle configuration for realizing the method of manufacturing a molding die according to the present invention, and the steps shown in FIGS. 1A and 1B are different in the cooling method of the mold frame filled with molten metal. And the step of FIG. 1 (c) in which the material cured after cooling is press-pressed. That is, the method for producing a molding die of the present invention includes a step of pouring a low melting point alloy material molten metal into a mold frame of the molding die and an entire outer periphery other than the upper surface of the mold frame filled with the low melting point alloy material molten metal. Or the process of cooling the final solidification part of the molten metal at a cooling rate equal to or higher than a predetermined cooling rate for the entire outer periphery including the upper surface, the process of taking out from the mold frame and press-pressing when the molten metal solidifies and has a predetermined solidification temperature, including.

In the present invention, the low-melting-point alloy material specifically includes zinc (Zn) as a main material, and contains an alloy component metal such as aluminum (Al), copper (Cu), magnesium (Mg), and the melting point is 400, for example. It is a zinc-based alloy (ZAS) at about ° C. The alloy component may contain a small amount of metal components other than those described above. In the present invention, a mold that maintains strength and durability, which is difficult to imagine in the past, is manufactured using a general-purpose ZAS material in which aluminum and copper are 5.0 wt% or less and magnesium is 0.1 wt% or less. By the way, with a general-purpose ZAS material, the mold manufactured by the method of pouring into the mold frame → casting → cooling and taking out, Brinell hardness HB101, tensile strength 215N / mm ² , shot number about 1,800 (drawing molding) is there.

  FIG. 1A is a principle configuration diagram of a partially open cooling method for a tank body that accommodates a mold frame poured in a cooling process, and a molten metal 10 in which a ZAS material ingot is melted is used as a mold for a molding die. The molten metal is poured into the frame 11 (not shown), the poured mold frame 11 is accommodated in a tank body 12 larger than the mold frame 11, and the refrigerant fluid is supplied to the gap 14 between the mold frame 11 and the wall surface of the tank body 12. The molten metal poured is cooled by charging and cooling the entire peripheral side surface and bottom surface of the mold frame 11. At this time, the coolant fluid is brought into contact with the entire outer wall surface of the mold frame to simultaneously cool the side wall surface and the bottom wall surface, and further rapidly cool the molten metal to refine the crystal grains and strengthen the molten metal structure during solidification. The hardness and strength are greatly improved.

  Next, in FIG.1 (c), the raw material used as the cavity surface side is press-pressed in the state which took out the hardened molten metal material from the mold frame 11, and was reversed. At this time, by press-pressing when the material temperature is a predetermined solidification temperature, work hardening occurs for the entire material, and the hardness is further improved.

  FIG.1 (b) is a principle block diagram of the cooling method by the closed-type tank body which cools the tank body which accommodates the casting_mold | template poured in the cooling process by arrange | positioning a mold frame in closed space, Etc., and the same configuration as in FIGS. 1A and 1C except that the entire circumference including the upper surface of the poured mold frame 11 is rapidly cooled.

  FIG. 2 shows the principle operation of the partially open cooling device for the tank body that accommodates the mold frame 11 according to FIG. 1A, and FIG. 5 is a flowchart thereof. First, the ZAS ingot is melted in a melting furnace (not shown), and the molten metal is poured into the mold frame 11 through a ladle (S1). A mold frame 11 made of, for example, iron filled with the ZAS molten metal 10 is accommodated in a box-shaped tank body 12 having an open upper surface. A gap 14 is provided between the outer periphery of the mold frame 11 and the tank body 12, and a refrigerant fluid 16 is introduced into the gap 14 (S2) to cool the entire outer periphery of the mold frame 11 and further melt the inside. Cool the center of the. At this time, when the refrigerant is a liquid, it is injected into the gap 14 and the outer periphery of the mold frame is cooled at the same time as the liquid level gradually rises. Maintains high strength. Further, the poured mold frame 11 is heated to about 400 ° C., but the cooling fluid temperature sufficient to rapidly cool the mold frame 11 is maintained. That is, in order to cool the final solidified portion of the molten metal at a cooling rate equal to or higher than a predetermined cooling rate, the entire outer periphery other than the upper surface of the mold frame filled with the molten metal is cooled in layers from the lower side to the upper side as the liquid level rises. . Specifically, it has been demonstrated that a mold that maintains desirable hardness and strength can be formed by cooling the molten metal at a cooling rate of 0.8 ° C./s or more (S3). In addition, the outer periphery of the mold frame 11 filled with the molten metal 10 is heated to, for example, about 400 ° C. For example, when the coolant is water, the water instantaneously reaches a high temperature. Therefore, an apparatus for rapidly cooling the mold frame carrying the molten metal which is a high temperature body is specifically required.

  Then, when the molten metal 10 is cured and at a predetermined solidification temperature, the molten metal 10 is taken out from the mold frame 11 and pressed (FIG. 1 (c)). The material temperature at the time of pressurization at this time is set to a temperature in the range of 50 ° C. ± 5 ° C. (S4), so that the degree of work hardening by press pressurization is increased and the shrinkage nest is pressed to improve the hardness.

  Next, referring to FIG. 3, an automatic supply device 20 for cooling fluid using an open top tank according to an embodiment of the present invention will be described. As described above, the tank is closed in the method of the present invention (FIG. 1). (B)) can also be applied. The automatic supply device 20 for cooling fluid according to the embodiment includes a first tank body 12A and a first tank body 12A having an open top surface that can accommodate a casting mold frame 11 and a cooling fluid (refrigerant) 16. A second tank body 13 that collects the cooling fluid overflowing from the first tank body, a reflux mechanism 22 that returns the fluid 162 in the second tank body 13 to the first tank body 12A, and a reflux mechanism And a fluid cooling device 24 provided in the reflux path 22a.

  In the figure, a mold frame 11 is a mold made of, for example, iron filled with a ZAS molten metal 10, and in this embodiment, a mold for injection molding of a punch portion of a mold to be finally molded is illustrated. . And it has accommodated in the 1st tank body 12A by making the base side of a punch into the upper surface side. The upper surface of the mold has an opening 11a, and the ZAS material melted by the ladle 26 is poured into the mold from this opening. The pouring into the mold frame may be performed with the empty mold frame 11 placed in the first tank body 12A, or the mold frame holding the molten metal after the pouring is placed in the first tank body 12A. May be transported.

  The first tank body 12A is for cooling the high temperature mold frame 11 that has been poured and holding the molten metal from the outer periphery together with the mold frame to cool the molten metal inside. In the embodiment, only the upper surface is opened. It is formed of a box-shaped tank having a size that can accommodate the mold frame 11 and form a gap 14 between the mold frame 11 and the wall surface of the tank. The gap 14 is a cooling fluid holding portion when cooling a mold frame having a temperature of about 400 ° C. from the entire outer periphery by introducing a cooling fluid such as public tap water. Since the molten metal in the mold frame needs to be rapidly cooled, the cooling fluid is continuously introduced into the gap 14 and overflows from the first tank body 12A as overflow water to the outside of the tank.

  In the present embodiment, the entire first tank body 12 </ b> A is accommodated in the second tank body 13. The second tank body 13 is a fluid holding means that contains the first tank body 12A and holds the cooling fluid overflowing from the first tank body 12A. The held fluid passes through the cooling device by the reflux mechanism 22. Then, it is again supplied into the first tank body 12A as cooling water.

  The reflux mechanism 22 is connected to the pump 32 installed together with the first tank body 12 </ b> A in the second tank body 13, the water tank 34 installed outside the second tank body 13 and connected to the pump 32, and the water tank 34. It includes a cooling device 24 and a supply pipe 36 that supplies cooling water from the cooling device to the first tank body 12A. The pump 32 and the water tank 34, and the water tank 34 and the cooling device 24 are connected by first and second connection pipes 38 and 40, respectively. The cooling device 24 is a cooling means for cooling water composed of a chiller unit or the like. The cooling medium 24 cools water from the water tank 34 by heat exchange with water using a cooled heat medium, and cools low-temperature water from the supply pipe 36 to the first tank. It is supplied to the gap 14 of the body 12A. The water that has been put into the first tank body 12A and brought into contact with the high temperature of the mold frame 11 and warmed is overflowed through the first tank body 12A, sucked by the pump 32, and sent to the water tank 34. A temperature sensor that measures the temperature of the final solidification part of the molten metal in the mold frame (not shown), a temperature sensor that measures the water temperature in the first tank body 12A, and a control device for cooling rate management, The cooling rate (for example, temperature measurement every unit time) is monitored to maintain the required cooling rate.

Next, the manufacturing process of the molding die according to the embodiment of the present invention will be described with reference to FIG.
A ZAS melt of about 400 ° C. in which the ingot is melted in a melting furnace (not shown) is poured into the mold frame 11 (FIG. 4A). At this time, the mold frame 11 is arranged with the opening surface corresponding to the bottom portion on the opposite side of the cavity surface as the upper surface. In FIG. 4A, illustration of the first and second tank bodies 12A and 13 for housing the mold frame is omitted. Next, the first cooling water that is circulated and used as cooling water is poured into the gap 14 between the mold frame and the tank wall of the first tank body 12A.

  As shown in FIG. 2 and FIG. 4 (b), the water as the coolant cools in a layered manner on the entire outer periphery except the upper surface of the mold frame that is filled with molten metal with the water level rising from the lower side toward the upper side. . As a result, the crystal grain refinement part is formed in high density by directing control that cools while simultaneously rising around the entire circumference at the water level, instead of cooling locally or in a plurality of dispersed manner with respect to the mold frame. By strengthening, hardness and strength can be greatly improved. At the same time, wear resistance is improved. In particular, by setting the cooling rate of the molten metal to a rate of 0.8 ° C./s or more, the material hardness is improved by the suppression of shrinkage and the effect of refining crystal grains and crystallized substances. When the cooling rate of the molten metal is less than 0.8 ° C./s, the crystal grains of the solidified body at the time of solidification become coarse and the hardness is lowered. The water in the gap 14 is heat-exchanged with the mold frame 11 containing the molten metal and rises in temperature, and overflows from the tank wall when reaching the height of the upper surface of the mold frame 11 or in the vicinity thereof (FIG. 4B), and the second tank. It is collected in the body 13. The collected hot water is sucked by the pump 32 and is pumped to the chiller unit 24 via the water tank 34. In the chiller unit, the hot water heat-exchanged with the refrigerant by the refrigerator is chilled and is again supplied from the supply pipe 36 to the gap 14 of the first tank body 12A. The reflux mechanism 22 circulates the coolant water, and always contacts the outer periphery of the mold frame 11 holding the molten metal to rapidly cool the molten metal.

  When the final solidified portion of the molten metal is 50 ° C. ± 5 ° C., the solidified and solidified material (10-1) is taken out from the mold frame, and the cavity portion is on the upper side of the lower base of the press as shown in FIG. Invert and arrange so that

  Then, pressurization is performed when the temperature of the material is 50 ° C. ± 5 ° C. (FIG. 4D). Pressurization increases the transition density due to work hardening and improves the hardness. The reason why the material temperature at the time of pressurization is 50 ° C. ± 5 ° C. is experimentally proved that work hardening effectively occurs when the pressure is applied within this temperature range, and the strength of the mold is maintained. . When the temperature at the time of press pressurization is less than 45 ° C., cracking occurs during processing, and when it exceeds 55 ° C., a desired strength cannot be obtained because the work hardening amount is small.

  For the cooling of the molten metal, the entire mold frame to be poured is accommodated in an open or closed tank body, and the cooling fluid is automatically supplied to the tank body in accordance with the material temperature of the molten metal by an automatic cooling fluid supply device. The specific method of cooling is not limited to the partially open-type tank body with the upper surface opened according to the above embodiment, but a poured mold frame is arranged in the closed-type tank body in FIG. It is good also as a structure cooled while supplying gas, such as refrigerant gas. Even in this case, the crystal frame is refined at a high density by simultaneously cooling the entire circumference of the mold frame instead of being locally or dispersed and cooling, thereby strengthening the structure and increasing the hardness. In addition, the strength can be greatly improved.

The molding die molded by the above-described process is performed by pouring the low melting point alloy material molten metal 10 into the mold frame 11 of the molding die and filling the entire outer periphery other than the upper surface of the mold frame 11 filled with the low melting point alloy material molten metal 10. Alternatively, the final solidified part of the molten metal is cooled at a cooling rate of 0.8 ° C./s or more while cooling the entire outer periphery including the upper surface, and the molten metal is solidified and the material temperature is within a range of 50 ° C. ± 5 ° C. It is a molding die that is sometimes removed from the mold frame and manufactured by pressurization, and the die satisfies a Brinell hardness of 151 or more and a tensile strength of 302 N / mm ² or more. By satisfying these conditions, low cost, good machinability and mold accuracy, and durability of more than 7,500 shots can be maintained, meeting the demand for small-lot, multi-product manufacturing. It is possible.

  The casting formed by press-pressing according to the above method is finally machined on the surface directly forming the cavity to complete the mold. However, since the material is, for example, a general-purpose ZAS material, Good machinability, short processing time, and less stroke. Further, in the method of the present invention, cast-fill molding that supports a member or the like that is necessary depending on a molded product by a manufactured mold can be performed.

  The mold formed by the manufacturing method of the mold for molding of the present invention is not limited to a metal mold for press molding such as metal processing, but is an injection mold for molding by injection filling a thermoplastic resin at a high pressure. Can also be applied.

Next, an example of the manufacturing method of the molding die of the present invention will be shown.
<Example 1>

  A general-purpose zinc-based alloy ZAS (aluminum 4.1 wt%, copper 3.0 wt%, magnesium 0.04 wt%, zinc balance) is melted at 400-450 ° C in an iron crucible, and the degree of superheat to the liquidus temperature is 30 Molten metal in a range not exceeding ℃ is poured into a mold frame for a punch-shaped mold having a base size: width 150 mm, length 390 mm, height 55 mm, punch head size: width 150 mm, length 150 mm, height 105 mm To do. The mold frame has a welded structure (box shape) of SUS409L and a steel plate with a thickness of 2 mm, and the mold frame is arranged with the cavity surface at the time of use at the time of actual mold forming as the lower side. After the pouring is completed, the oxide on the surface of the molten metal in the mold frame is removed with a brush, and then water is supplied from the chiller unit to the gap between the tank wall and the mold frame in the molten metal temperature range just above the melting point. The molten metal (directly the outer periphery of the mold frame) was forcibly cooled. When the upper surface temperature of the material reaches about 60 ° C, the entire mold frame is taken out of the tank body, the mold frame is inverted, the material is taken out, and set in the press lower mold so that the cavity surface of the molding die, that is, the lower side becomes the upper surface during casting. did. When the temperature of the material cavity surface taken out from the mold reached about 50 ° C., the movable mold was lowered at a speed of 45 mm / s or more and pressurized (free forging) at a surface pressure of 220 MPa or more. Thereby, the upsetting amount at this time was about 10 mm.

In FIG. 6, the performance evaluation of the example and the comparative example was performed on the mold material manufactured by the above method. The hardness (HB), tensile strength (N / mm ² ), and shot value were obtained using a Brinell tester and a tensile load tester, respectively. In addition, in Examples 1 to 7 in FIG. 6, the number of shots at the time of data acquisition is shown, and in actuality, there may still be those that are still in operation after counting 20,000 shots or more in the subsequent test. It has been confirmed experimentally.

  Examples 1 to 7 are molds satisfying the cooling rate and pressurizing temperature conditions, Examples 8 to 13 are molds that do not have either or both conditions, and Comparative Examples 1 and 2 are press-pressed. It is a result when there is no. The number of shots is 1,800 as a benchmark in general-purpose ZAS.

  The manufacturing method and the molding die of the molding die of the present invention described above are not limited to the above-described embodiments, and are made within the scope not departing from the essence of the invention described in the claims. Any modifications are also included in the present invention. Further, although not particularly distinguished in the description of the title of the invention, the scope of claims, and the embodiments, as long as the requirements described in the scope of claims of the present invention are satisfied, in addition to the finished product mold, Semi-finished molds before final machining are also included in the present invention.

  The method for producing a molding die and the molding die of the present invention can be used in the field of automobile parts, various industrial equipment, parts thereof, general household goods and other press or injection molding dies.

DESCRIPTION OF SYMBOLS 10 Molten metal 11 Mold frame 12 Tank body 12A 1st tank body 13 2nd tank body 14 Gap 16 Refrigerant fluid 20 Fluid automatic supply device 22 Recirculation mechanism 24 Cooling device 32 Pump 34 Water tank 36 Supply pipe

  The present invention relates to a method for manufacturing a molding die and a molding die, and more particularly, to a method for manufacturing a molding die using a low melting point alloy material excellent in machinability.

  Metal molds for producing metal or synthetic resin parts by plastic working such as press working or injection molding are known, and alloyed steel materials are generally used. Recently, there has been a growing need for molds that have the strength and durability required for press processing, etc. while having good machinability and low cost in response to the need for shortening the product trend cycle and low volume production. Yes. Conventionally, Patent Document 1 suggests a press die using a low melting point alloy such as ZAS.

JP-A-5-195121

  Patent Document 1 proposes a zinc alloy mold in which the alloy component ratio of aluminum and copper is increased to improve the wear resistance against iron. However, in the metal mold of Patent Document 1, a large amount of alloy elements of aluminum and copper are added as materials to improve wear resistance, and the manufacturing cost is high. Moreover, in the metal mold | die of patent document 1, since alloy components, such as aluminum and copper, are mainly added, fluidity | liquidity falls easily by adding a large amount of components with high melting point and large specific gravity. For this reason, component segregation, reverse shrinkage, and internal shrinkage (shrinkage cavities inside the casting) are likely to occur, and the component design is complicated and takes time because these must be taken into consideration. Furthermore, the aluminum phase lighter than the zinc melt rises due to the addition of a large amount of aluminum. As a result, the solidification temperature rises in this part. In this regard, in the general-purpose ZAS alloy, solidification starts from the lower part, and the upper part becomes the final solidified part and is closed.) In order to prevent such a phenomenon, a top heat method is used in which the upper part of the casting is heated by a gas burner and the final solidified part is brought to the upper part. Grain refinement strengthening could not be expected, and there was a risk that the hardness would decrease.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a method for manufacturing a molding die having excellent machinability, strength and durability at a low cost and for molding. To provide molds.

In order to solve the above problems, a method for producing a molding die according to the present invention is a low melting point alloy material that melts at a temperature of at least 400 to 450 ° C. with a superheat degree exceeding the liquidus temperature as the melting point in the range of 30 ° C. predetermined and a step of pouring the molten metal into a mold frame of the mold (S1), the entire periphery including the entire circumference or upper surface other than the top surface of the flask filled with the low melting point alloy melt the final solidification portion of the molten metal And a step of cooling at a cooling rate equal to or higher than the cooling rate (S2, S3) and a step of taking out from the mold frame and pressurizing (S4) when the molten metal is solidified and at a predetermined solidification temperature. .

  At that time, the cooling rate of the molten metal is preferably 0.8 ° C./s or more.

  Moreover, it is good for the raw material temperature at the time of pressurization of the solidified molten metal to be the temperature in the range of 50 degreeC +/- 5 degreeC.

  In addition, the entire mold frame to be poured is accommodated in an open or closed tank body, and the cooling fluid is automatically supplied to the tank body according to the material temperature of the molten metal by an automatic cooling fluid supply device. It is good to do by supplying.

  In addition, the cooling fluid automatic supply device 20 includes an open top first tank body 12A capable of accommodating a casting mold frame 11 for pouring and a cooling fluid 16 to be introduced and arranged outside the casting mold frame 11; The second tank body 13 that contains the first tank body 12A and collects the cooling fluid 16 that overflows from the first tank body, and the reflux that causes the fluid 162 in the second tank body 13 to flow back into the first tank body 12A. The mechanism 22 and the fluid cooling device 24 provided in the reflux path 22a by the reflux mechanism may be included.

  Furthermore, when the molten metal in the mold frame is cooled while supplying the coolant fluid to the outer periphery of the mold frame, the cooling position in the circumferential direction may be moved in layers from the bottom to the bottom.

  According to the method for manufacturing a molding die of the present invention, a step of pouring a low melting point alloy material molten metal into the mold frame of the molding die, and the entire outer periphery other than the upper surface of the mold frame filled with the low melting point alloy material molten metal Or the process of cooling the final solidification part of the molten metal at a cooling rate equal to or higher than a predetermined cooling rate for the entire outer periphery including the upper surface, the process of taking out from the mold frame and press-pressing when the molten metal solidifies and has a predetermined solidification temperature, The general-purpose zinc-based alloy is a general-purpose zinc-based alloy that maintains good machinability at a low cost, and at the same time cools the entire circumference of the mold frame instead of cooling locally or in multiple dispersions. By doing so, the refinement | miniaturization part of the crystal grain of a molten material is formed in high density, and a structure | tissue can be strengthened and hardness and intensity | strength can be improved significantly.

  At that time, the cooling rate of the molten metal is 0.8 ° C./s or more, and the material temperature at the time of pressurization of the solidified molten metal is 50 ° C. ± 5 ° C. Although it is a zinc-based alloy, the hardness can be greatly improved, and the durability can be improved.

  In addition, the entire mold frame to be poured is accommodated in an open or closed tank body, and the cooling fluid is automatically supplied to the tank body according to the material temperature of the molten metal by an automatic cooling fluid supply device. Since it is performed by supplying, rapid cooling can be realized reliably by continuously supplying cooling refrigerant exceeding heat exchange with a high temperature of about 400 ° C.

  An automatic cooling fluid supply apparatus includes a first tank body having an open top surface capable of accommodating a mold frame for pouring, a cooling fluid introduced and disposed outside the mold frame, and a first tank body. A second tank body that collects the cooling fluid that overflows from the first tank body, a reflux mechanism that recirculates the fluid in the second tank body into the first tank body, and a fluid provided in a reflux path by the reflux mechanism. Therefore, rapid cooling can be realized reliably by continuously supplying a coolant for cooling the molten metal.

  When cooling the molten metal in the mold frame while supplying the coolant fluid to the outer periphery of the mold frame, the cooling position in the circumferential direction moves from bottom to top while cooling in layers, so the stacking position of the refrigerant is all around Since cooling is performed while rising at the same time, crystal grain refined portions are stacked and formed at a high density, and the structure can be strengthened to significantly improve the hardness and strength. At the same time, wear resistance is improved.

  Further, according to the molding die of the present invention, the low melting point alloy material molten metal is poured into the mold frame of the molding die, and the entire outer periphery or top surface other than the top surface of the mold frame filled with the low melting point alloy material molten metal is poured. The final solidification part of the molten metal is cooled at a cooling rate of 0.8 ° C./s or more while cooling the entire outer periphery, and the mold is solidified when the molten metal is solidified and the material temperature is in the range of 50 ° C. ± 5 ° C. Because it is a molding die that is produced by press-pressing it out of the frame, it is a general-purpose zinc-based alloy that can be dispersed locally or in multiple locations on the mold frame while maintaining good machinability at low cost. By cooling the entire circumference at the same time instead of cooling, the refined portion of the crystal grains of the molten material is formed at a high density. As a result, the structure can be strengthened and the hardness and strength can be greatly improved.

  According to the molding die of the present invention, since the molding die is a molding die satisfying a Brinell hardness of 151 or more and a tensile strength of 302 N / mm 2 or more, a commercially available ZAS material is used. It is possible to maintain unprecedented high hardness and strength by a simple method, and also to maintain durability.

It is a principle process explanatory drawing of the manufacturing method of the metal mold | die of this invention, (a) is explanatory drawing of the method of arrange | positioning and cooling the casting_mold | template poured in the tank in which one part was open | released, (b) The explanatory view of the method of arranging and cooling the poured mold in the closed tank, (c) is the figure explaining the pressurization process of the hardened material. FIG. 2 is an enlarged explanatory view of FIG. It is explanatory drawing of the cooling structure of the mold frame by the partially open tank of the method of this invention. The process of the metal mold | die manufacturing method in the case of using the partially open tub as embodiment of the method of this invention is demonstrated, Fig. (A) is explanatory drawing of the state which pours in a mold frame, (b) FIG. 4C is an explanatory diagram of a cooling process, FIG. 3C is an explanatory diagram of a state in which a cured material is inverted and placed on a press stand, and FIG. 4D is a diagram illustrating a state in which the cured material of FIG. It is. It is a flowchart figure of the principle process of the method of this invention. It is a figure which shows the characteristic test result of the Example of a metal mold | die manufactured using the method of this invention, and a comparative example.

  The present invention relates to a method of manufacturing a mold itself of a molding machine used for molding an article such as a press or injection molding, and a mold. Examples include a mold for press molding such as metal processing such as a die and a punch, and a mold for injection-filling and molding a thermoplastic resin at a high pressure.

  1 and 2 are explanatory views of the principle configuration for realizing the method of manufacturing a molding die according to the present invention, and the steps shown in FIGS. 1A and 1B are different in the cooling method of the mold frame filled with molten metal. And the step of FIG. 1 (c) in which the material cured after cooling is press-pressed. That is, the method for producing a molding die of the present invention includes a step of pouring a low melting point alloy material molten metal into a mold frame of the molding die and an entire outer periphery other than the upper surface of the mold frame filled with the low melting point alloy material molten metal. Or the process of cooling the final solidification part of the molten metal at a cooling rate equal to or higher than a predetermined cooling rate for the entire outer periphery including the upper surface, the process of taking out from the mold frame and press-pressing when the molten metal solidifies and has a predetermined solidification temperature, including.

In the present invention, the low-melting-point alloy material specifically includes zinc (Zn) as a main material, and contains an alloy component metal such as aluminum (Al), copper (Cu), magnesium (Mg), and the melting point is 400, for example. It is a zinc-based alloy (ZAS) at about ° C. The alloy component may contain a small amount of metal components other than those described above. In the present invention, a mold that maintains strength and durability, which is difficult to imagine in the past, is manufactured using a general-purpose ZAS material in which aluminum and copper are 5.0 wt% or less and magnesium is 0.1 wt% or less. By the way, using a general-purpose ZAS material, the mold manufactured by pouring into the mold frame → casting → cooling and taking out has a Brinell hardness HB101, a tensile strength of 215 N / mm2, and a shot number of about 1,800 (drawing). .

  FIG. 1A is a principle configuration diagram of a partially open cooling method for a tank body that accommodates a mold frame poured in a cooling process, and a molten metal 10 in which a ZAS material ingot is melted is used as a mold for a molding die. The molten metal is poured into the frame 11 (not shown), the poured mold frame 11 is accommodated in a tank body 12 larger than the mold frame 11, and the refrigerant fluid is supplied to the gap 14 between the mold frame 11 and the wall surface of the tank body 12. The molten metal poured is cooled by charging and cooling the entire peripheral side surface and bottom surface of the mold frame 11. At this time, the coolant fluid is brought into contact with the entire outer wall surface of the mold frame to simultaneously cool the side wall surface and the bottom wall surface, and further rapidly cool the molten metal to refine the crystal grains and strengthen the molten metal structure during solidification. The hardness and strength are greatly improved.

  Next, in FIG.1 (c), the raw material used as the cavity surface side is press-pressed in the state which took out the hardened molten metal material from the mold frame 11, and was reversed. At this time, by press-pressing when the material temperature is a predetermined solidification temperature, work hardening occurs for the entire material, and the hardness is further improved.

  FIG.1 (b) is a principle block diagram of the cooling method by the closed-type tank body which cools the tank body which accommodates the casting_mold | template poured in the cooling process by arrange | positioning a mold frame in closed space, Etc., and the same configuration as in FIGS. 1A and 1C except that the entire circumference including the upper surface of the poured mold frame 11 is rapidly cooled.

  FIG. 2 shows the principle operation of the partially open cooling device for the tank body that accommodates the mold frame 11 according to FIG. 1A, and FIG. 5 is a flowchart thereof. First, the ZAS ingot is melted in a melting furnace (not shown), and the molten metal is poured into the mold frame 11 through a ladle (S1). A mold frame 11 made of, for example, iron filled with the ZAS molten metal 10 is accommodated in a box-shaped tank body 12 having an open upper surface. A gap 14 is provided between the outer periphery of the mold frame 11 and the tank body 12, and a refrigerant fluid 16 is introduced into the gap 14 (S2) to cool the entire outer periphery of the mold frame 11 and further melt the inside. Cool the center of the. At this time, when the refrigerant is a liquid, it is injected into the gap 14 and the outer periphery of the mold frame is cooled at the same time as the liquid level gradually rises. Maintains high strength. Further, the poured mold frame 11 is heated to about 400 ° C., but the cooling fluid temperature sufficient to rapidly cool the mold frame 11 is maintained. That is, in order to cool the final solidified portion of the molten metal at a cooling rate equal to or higher than a predetermined cooling rate, the entire outer periphery other than the upper surface of the mold frame filled with the molten metal is cooled in layers from the lower side to the upper side as the liquid level rises. . Specifically, it has been demonstrated that a mold that maintains desirable hardness and strength can be formed by cooling the molten metal at a cooling rate of 0.8 ° C./s or more (S3). In addition, the outer periphery of the mold frame 11 filled with the molten metal 10 is heated to, for example, about 400 ° C. For example, when the coolant is water, the water instantaneously reaches a high temperature. Therefore, an apparatus for rapidly cooling the mold frame carrying the molten metal which is a high temperature body is specifically required.

  Then, when the molten metal 10 is cured and at a predetermined solidification temperature, the molten metal 10 is taken out from the mold frame 11 and pressed (FIG. 1 (c)). The material temperature at the time of pressurization at this time is set to a temperature in the range of 50 ° C. ± 5 ° C. (S4), so that the degree of work hardening by press pressurization is increased and the shrinkage nest is pressed to improve the hardness.

  Next, referring to FIG. 3, an automatic supply device 20 for cooling fluid using an open top tank according to an embodiment of the present invention will be described. As described above, the tank is closed in the method of the present invention (FIG. 1). (B)) can also be applied. The automatic supply device 20 for cooling fluid according to the embodiment includes a first tank body 12A and a first tank body 12A having an open top surface that can accommodate a casting mold frame 11 and a cooling fluid (refrigerant) 16. A second tank body 13 that collects the cooling fluid overflowing from the first tank body, a reflux mechanism 22 that returns the fluid 162 in the second tank body 13 to the first tank body 12A, and a reflux mechanism And a fluid cooling device 24 provided in the reflux path 22a.

  In the figure, a mold frame 11 is a mold made of, for example, iron filled with a ZAS molten metal 10, and in this embodiment, a mold for injection molding of a punch portion of a mold to be finally molded is illustrated. . And it has accommodated in the 1st tank body 12A by making the base side of a punch into the upper surface side. The upper surface of the mold has an opening 11a, and the ZAS material melted by the ladle 26 is poured into the mold from this opening. The pouring into the mold frame may be performed with the empty mold frame 11 placed in the first tank body 12A, or the mold frame holding the molten metal after the pouring is placed in the first tank body 12A. May be transported.

The first tank body 12A is than also give an effect to cool the interior of the molten metal to cool the hot flask 11 holding the molten metal was poured from the mold each frame periphery, in the embodiment, the open upper surface only It is formed of a box-shaped tank having a size that can accommodate the mold frame 11 and form a gap 14 between the mold frame 11 and the wall surface of the tank. The gap 14 is a cooling fluid holding portion when cooling a mold frame having a temperature of about 400 ° C. from the entire outer periphery by introducing a cooling fluid such as public tap water. Since the molten metal in the mold frame needs to be rapidly cooled, the cooling fluid is continuously introduced into the gap 14 and overflows from the first tank body 12A as overflow water to the outside of the tank.

  In the present embodiment, the entire first tank body 12 </ b> A is accommodated in the second tank body 13. The second tank body 13 is a fluid holding means that contains the first tank body 12A and holds the cooling fluid overflowing from the first tank body 12A. The held fluid passes through the cooling device by the reflux mechanism 22. Then, it is again supplied into the first tank body 12A as cooling water.

  The reflux mechanism 22 is connected to the pump 32 installed together with the first tank body 12 </ b> A in the second tank body 13, the water tank 34 installed outside the second tank body 13 and connected to the pump 32, and the water tank 34. It includes a cooling device 24 and a supply pipe 36 that supplies cooling water from the cooling device to the first tank body 12A. The pump 32 and the water tank 34, and the water tank 34 and the cooling device 24 are connected by first and second connection pipes 38 and 40, respectively. The cooling device 24 is a cooling means for cooling water composed of a chiller unit or the like. The cooling medium 24 cools water from the water tank 34 by heat exchange with water using a cooled heat medium, and cools low-temperature water from the supply pipe 36 to the first tank. It is supplied to the gap 14 of the body 12A. The water that has been put into the first tank body 12A and brought into contact with the high temperature of the mold frame 11 and warmed is overflowed through the first tank body 12A, sucked by the pump 32, and sent to the water tank 34. A temperature sensor that measures the temperature of the final solidification part of the molten metal in the mold frame (not shown), a temperature sensor that measures the water temperature in the first tank body 12A, and a control device for cooling rate management, The cooling rate (for example, temperature measurement every unit time) is monitored to maintain the required cooling rate.

Next, the manufacturing process of the molding die according to the embodiment of the present invention will be described with reference to FIG.
A ZAS melt of about 400 ° C. in which the ingot is melted in a melting furnace (not shown) is poured into the mold frame 11 (FIG. 4A). At this time, the mold frame 11 is arranged with the opening surface corresponding to the bottom portion on the opposite side of the cavity surface as the upper surface. In FIG. 4A, illustration of the first and second tank bodies 12A and 13 for housing the mold frame is omitted. Next, the first cooling water that is circulated and used as cooling water is poured into the gap 14 between the mold frame and the tank wall of the first tank body 12A.

  As shown in FIG. 2 and FIG. 4 (b), the water as the coolant cools in a layered manner on the entire outer periphery except the upper surface of the mold frame that is filled with molten metal with the water level rising from the lower side toward the upper side. . As a result, the crystal grain refinement part is formed in high density by directing control that cools while simultaneously rising around the entire circumference at the water level, instead of cooling locally or in a plurality of dispersed manner with respect to the mold frame. By strengthening, hardness and strength can be greatly improved. At the same time, wear resistance is improved. In particular, by setting the cooling rate of the molten metal to a rate of 0.8 ° C./s or more, the material hardness is improved by the suppression of shrinkage and the effect of refining crystal grains and crystallized substances. When the cooling rate of the molten metal is less than 0.8 ° C./s, the crystal grains of the solidified body at the time of solidification become coarse and the hardness is lowered. The water in the gap 14 is heat-exchanged with the mold frame 11 containing the molten metal and rises in temperature, and overflows from the tank wall when reaching the height of the upper surface of the mold frame 11 or in the vicinity thereof (FIG. 4B), and the second tank. It is collected in the body 13. The collected hot water is sucked by the pump 32 and is pumped to the chiller unit 24 via the water tank 34. In the chiller unit, the hot water heat-exchanged with the refrigerant by the refrigerator is chilled and is again supplied from the supply pipe 36 to the gap 14 of the first tank body 12A. The reflux mechanism 22 circulates the coolant water, and always contacts the outer periphery of the mold frame 11 holding the molten metal to rapidly cool the molten metal.

  When the final solidified portion of the molten metal is 50 ° C. ± 5 ° C., the solidified and solidified material (10-1) is taken out from the mold frame, and the cavity portion is on the upper side of the lower base of the press as shown in FIG. Invert and arrange so that

  Then, pressurization is performed when the temperature of the material is 50 ° C. ± 5 ° C. (FIG. 4D). Pressurization increases the transition density due to work hardening and improves the hardness. The reason why the material temperature at the time of pressurization is 50 ° C. ± 5 ° C. is experimentally proved that work hardening effectively occurs when the pressure is applied within this temperature range, and the strength of the mold is maintained. . When the temperature at the time of press pressurization is less than 45 ° C., cracking occurs during processing, and when it exceeds 55 ° C., a desired strength cannot be obtained because the work hardening amount is small.

  For the cooling of the molten metal, the entire mold frame to be poured is accommodated in an open or closed tank body, and the cooling fluid is automatically supplied to the tank body in accordance with the material temperature of the molten metal by an automatic cooling fluid supply device. The specific method of cooling is not limited to the partially open-type tank body with the upper surface opened according to the above embodiment, but a poured mold frame is arranged in the closed-type tank body in FIG. It is good also as a structure cooled while supplying gas, such as refrigerant gas. Even in this case, the crystal frame is refined at a high density by simultaneously cooling the entire circumference of the mold frame instead of being locally or dispersed and cooling, thereby strengthening the structure and increasing the hardness. In addition, the strength can be greatly improved.

  The molding die molded by the above-described process is performed by pouring the low melting point alloy material molten metal 10 into the mold frame 11 of the molding die and filling the entire outer periphery other than the upper surface of the mold frame 11 filled with the low melting point alloy material molten metal 10. Alternatively, the final solidified part of the molten metal is cooled at a cooling rate of 0.8 ° C./s or more while cooling the entire outer periphery including the upper surface, and the molten metal is solidified and the material temperature is within a range of 50 ° C. ± 5 ° C. It is a molding die that is sometimes removed from the mold frame and manufactured by pressurization, and the die satisfies a Brinell hardness of 151 or more and a tensile strength of 302 N / mm 2 or more. By satisfying these conditions, low cost, good machinability and mold accuracy, and durability of more than 7,500 shots can be maintained, meeting the demand for small-lot, multi-product manufacturing. It is possible.

  The casting formed by press-pressing according to the above method is finally machined on the surface directly forming the cavity to complete the mold. However, since the material is, for example, a general-purpose ZAS material, Good machinability, short processing time, and less stroke. Further, in the method of the present invention, cast-fill molding that supports a member or the like that is necessary depending on a molded product by a manufactured mold can be performed.

  The mold formed by the manufacturing method of the mold for molding of the present invention is not limited to a metal mold for press molding such as metal processing, but is an injection mold for molding by injection filling a thermoplastic resin at a high pressure. Can also be applied.

Next, an example of the manufacturing method of the molding die of the present invention will be shown.
<Example 1>

  A general-purpose zinc-based alloy ZAS (aluminum 4.1 wt%, copper 3.0 wt%, magnesium 0.04 wt%, zinc balance) is melted at 400-450 ° C in an iron crucible, and the degree of superheat to the liquidus temperature is 30 Molten metal in a range not exceeding ℃ is poured into a mold frame for a punch-shaped mold having a base size: width 150 mm, length 390 mm, height 55 mm, punch head size: width 150 mm, length 150 mm, height 105 mm To do. The mold frame has a welded structure (box shape) of SUS409L and a steel plate with a thickness of 2 mm, and the mold frame is arranged with the cavity surface at the time of use at the time of actual mold forming as the lower side. After the pouring is completed, the oxide on the surface of the molten metal in the mold frame is removed with a brush, and then water is supplied from the chiller unit to the gap between the tank wall and the mold frame in the molten metal temperature range just above the melting point. The molten metal (directly the outer periphery of the mold frame) was forcibly cooled. When the upper surface temperature of the material reaches about 60 ° C, the entire mold frame is taken out of the tank body, the mold frame is inverted, the material is taken out, and set in the press lower mold so that the cavity surface of the molding die, that is, the lower side becomes the upper surface during casting. did. When the temperature of the material cavity surface taken out from the mold reached about 50 ° C., the movable mold was lowered at a speed of 45 mm / s or more and pressurized (free forging) at a surface pressure of 220 MPa or more. Thereby, the upsetting amount at this time was about 10 mm.

  In FIG. 6, the performance evaluation of the example and the comparative example was performed on the mold material manufactured by the above method. The hardness (HB), tensile strength (N / mm2), and shot value were obtained using a Brinell tester and a tensile load tester, respectively. In addition, in Examples 1 to 7 in FIG. 6, the number of shots at the time of data acquisition is shown, and in actuality, there may still be those that are still in operation after counting 20,000 shots or more in the subsequent test. It has been confirmed experimentally.

  Examples 1 to 7 are molds satisfying the cooling rate and pressurizing temperature conditions, Examples 8 to 13 are molds that do not have either or both conditions, and Comparative Examples 1 and 2 are press-pressed. It is a result when there is no. The number of shots is 1,800 as a benchmark in general-purpose ZAS.

  The manufacturing method and the molding die of the molding die of the present invention described above are not limited to the above-described embodiments, and are made within the scope not departing from the essence of the invention described in the claims. Any modifications are also included in the present invention. Further, although not particularly distinguished in the description of the title of the invention, the scope of claims, and the embodiments, as long as the requirements described in the scope of claims of the present invention are satisfied, in addition to the finished product mold, Semi-finished molds before final machining are also included in the present invention.

  The method for producing a molding die and the molding die of the present invention can be used in the field of automobile parts, various industrial equipment, parts thereof, general household goods and other press or injection molding dies.

DESCRIPTION OF SYMBOLS 10 Molten metal 11 Mold frame 12 Tank body 12A 1st tank body 13 2nd tank body 14 Gap 16 Refrigerant fluid 20 Fluid automatic supply device 22 Recirculation mechanism 24 Cooling device 32 Pump 34 Water tank 36 Supply pipe

Claims (8)

Pouring a low melting point alloy material molten metal into a mold frame of a molding die;
Cooling the final solidified part of the molten metal at a cooling rate equal to or higher than a predetermined cooling rate for the entire outer periphery other than the upper surface of the mold frame filled with the low melting point alloy material molten metal or the entire outer periphery including the upper surface;
And a step of taking out from the mold frame and press-pressing when the molten metal is solidified and at a predetermined solidification temperature.   The method for producing a molding die according to claim 1, wherein the cooling rate of the molten metal is 0.8 ° C / s or more.   The method for producing a molding die according to claim 1 or 2, wherein a material temperature at the time of pressurization of the solidified molten metal is a temperature within a range of 50 ° C ± 5 ° C. The molten metal is cooled by storing the entire casting mold frame in an open or closed tank body,
4. The molding die according to claim 1, wherein the cooling fluid is automatically supplied to the tank body in accordance with the material temperature of the molten metal by an automatic cooling fluid supply device. 5. Production method. Automatic cooling fluid supply device
A first tank body with an open top surface capable of accommodating a casting mold frame for pouring, and a cooling fluid introduced and disposed outside the casting mold frame;
A second tank body that houses the first tank body and collects the cooling fluid overflowing from the first tank body;
A reflux mechanism for refluxing fluid in the second tank into the first tank;
The method for manufacturing a molding die according to claim 4, further comprising a fluid cooling device provided in a reflux path by the reflux mechanism. When cooling the molten metal in the mold frame while charging the coolant fluid to the outer periphery of the mold frame,
6. The method for manufacturing a molding die according to claim 5, wherein the cooling position in the circumferential direction is moved from bottom to top while moving in layers. Pouring the low melting point alloy material molten metal into the mold frame of the mold,
Cooling the final solidified part of the molten metal at a cooling rate of 0.8 ° C./s or more while cooling the entire outer periphery other than the upper surface of the mold frame filled with the low melting point alloy material molten metal or the entire outer periphery including the upper surface,
A mold for molding which is produced by pressing and taking out from the mold frame when the molten metal solidifies and the temperature of the material is in the range of 50 ° C. ± 5 ° C. 8. The molding die according to claim 7, wherein a Brinell hardness of 151 or more and a tensile strength of 302 N / mm ² or more are satisfied.

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