JP2882562B2 - Temperature control method of molding die and molding die - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for molding a metal or a resin which requires heating or cooling, in particular, a mold for which heating and cooling are repeated synchronously with a molding mold having a relatively small molding pressure. The present invention relates to a mold temperature control method and a molding die.

[0002]

2. Description of the Related Art In conventional low-pressure molding dies, an iron-based low alloy material is mainly used as a mold base material.
As the mold temperature control time becomes longer, copper alloy forming dies are used as an improvement measure to shorten the temperature control time, and holes are made in the mold by drilling, and blind A heating or cooling medium passage hole is formed by inserting a plug or the like.

[0003]

However, in the conventional molding die, when forming a heating or cooling medium passage hole for oil, water or gas, etc., a so-called heat medium passage hole, in the molding die. There is a restriction in drilling that it is difficult to form a desired heat medium passage along the mold cavity surface with a straight line combination of drilled holes, which limits the practical application. . Furthermore, in order to solve these problems, a method of preforming a metal pipe for a heat medium passage and then casting the same with a molten metal as a base material of a metal mold to produce a mold for low pressure molding is being tested. However, the theory had not been established and it had not been put to practical use.

[0004] In view of the current situation as described above, iron-based, copper-based, and aluminum-based alloys which may be used as a base material of a molding die are viewed from both the heating / cooling theory and the die manufacturing technology. There are the following issues. First,
(1) From the viewpoint of heating and cooling theory, the material must have a large temperature diffusion coefficient [thermal conductivity / (specific heat × density)] and excellent castability for practical use. Incidentally, the temperature diffusion coefficient is copper (0.7 ~
1.3), aluminum (1), iron (0.2). Further, it is desirable that the laminar flow film on the heat medium side is thin and the flow rate of the heat medium is large.

[0005] Next, from the viewpoint of (2) mold manufacturing technology, <Mold base metal side> Since the temperature of the molten metal is high, it is difficult to select a metal pipe material for the copper base metal base material. It is difficult to loosen, and the mold base material is highly oxidized and expensive. Aluminum mold base material is easy to cast and the base material is relatively inexpensive. Iron-based mold base materials are inexpensive,
As in the case of the copper-based alloy, the high temperature of the molten metal makes it difficult to select the material of the metal pipe, making it difficult to cast the metal, and severely oxidizing the mold base material. <As-cast metal pipe side> In the case of copper-based metal pipes, if aluminum or copper is used as the base material of the mold, it will melt during casting. In the case of an aluminum-based metal pipe, if an aluminum-based or copper-based material is used as a mold base material, the aluminum-based metal pipe is more severely melted than the copper-based metal pipe. As a countermeasure against metal pipe erosion as described above,
When the erosion inhibitor is applied to the outer surface of the metal pipe, heat transfer is hindered because a heat insulating layer is formed. In the case of iron-based metal pipes, it is difficult to melt, but the temperature diffusion coefficient is small and heat transfer is difficult. Many problems such as this have not been sufficiently elucidated and have been brought to the present.

The present invention focuses on the above-mentioned conventional problems, and is directed to a molding machine having a cast-in pipe having an optimum pipe diameter and wall thickness capable of preventing molding defects such as surface defects, deformation and seizure of molded products. It is an object of the present invention to provide a mold temperature control method and a molding die.

[0007]

In order to achieve the above object, a method for controlling the temperature of a molding die and a first invention of a molding die according to the present invention provide a method of controlling a temperature of a plurality of molding dies penetrating a die. in mold temperature control method which is adapted to adjust the is allowed by the mold temperature flowing heating or cooling medium consisting of liquid tone tube, gold
6,000 The Reynolds number of the heating or cooling medium flowing through was insert cast along the mold cavity surface the temperature control pipe
The temperature was controlled at 12,000. Further, in the second invention, a metal mold is provided with a heating or cooling medium passage hole near a cavity of the metal mold by casting a metal pipe inside the metal mold. An aluminum alloy is used as a base material of the mold, and an iron-based material is used as the metal pipe. The dimensions of the metal pipe are 7 to 13 mm in inner diameter, and the ratio of outer to inner diameter is 1.2 to 1.
7. Arrange pitch of metal pipe to 1.5 times of metal pipe inner diameter.
The depth from the mold cavity surface to the outer peripheral upper surface of the metal pipe was 5 to 25 mm.

[0008]

According to the above configuration, the total heat capacity of the molding die is minimized by using an aluminum-based alloy for the base material of the mold and an iron-based alloy for the metal pipe, and the castability is improved. Further, the metal pipe is formed into a heat medium passage shape along a mold cavity surface having a high degree of freedom. Minimize the thickness of the iron-based metal pipe and reduce the number of Reynolds nozzles to 6,000 to 12,000 to improve the thermal conductivity of the metal pipe and the laminar film formed on the inner wall of the pipe. I do. When dimensioning and arranging the inside and outside diameters of metal pipes,
Perform optimization taking into account thermal conductivity, preformability, and heat medium circulation power. be able to.

For this reason, a metal pipe serving as a heating or cooling medium passage hole for controlling the temperature of the mold is formed by the insert casting method. By setting the Reynolds (Re) number flowing in the medium passage hole to 6,000 to 12,000, the inner diameter of the metal pipe is 7 to 13 mm,
The inner diameter ratio is 1.2 to 1.7, the arrangement pitch of the metal pipes is 1.5 to 3 times the inner diameter of the metal pipe, and the depth from the mold cavity surface to the outer peripheral upper surface of the metal pipe is 5 to 25 mm. Further, not only a copper alloy but also an iron-based or stainless steel can be used for the metal pipe. In addition, the mold material for efficient heating or cooling has a large influence on the heat capacity rather than being determined only by the temperature diffusion coefficient.
By using an aluminum alloy (AC4C) having a small heat capacity, a molding die having good heating and cooling efficiency and capable of controlling the temperature of the die can be obtained.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a molding die according to the present invention.

FIG. 1 is a diagram showing the temperature control piping of a molding die, FIG. 2 is a diagram showing the relationship between Reynolds number and die heating time, FIG. 3 is an explanatory diagram for heating the die by a heat medium, and FIG. 5 is a diagram showing the relationship between the inner diameter of the temperature control pipe forming the cooling medium passage hole and the heating time of the mold, FIG. 5 is a diagram showing the relationship between the outer diameter / inner diameter ratio of the temperature control pipe and the heating time of the mold, and FIG. Figure 7 shows the relationship between the arrangement pitch of the adjusting pipe and the mold heating time. Fig. 7 shows the relationship between the distance from the mold cavity surface to the top of the temperature adjusting pipe and the mold heating time. Fig. 8 shows the mold material and molding cycle time. FIG. 9 is a front view of a mold using another piping method for the temperature control pipe according to the embodiment of the present invention.

As shown in FIG. 1, first, a copper pipe as a temperature control pipe 2 is set at a predetermined position in a cavity of a mold in order to provide a hole for a heating / cooling medium passage for temperature control in a molding die. The molten metal was poured into the cavity of the mold, and after solidifying the molten metal, it was taken out of the mold to form a molding die. In addition to the above-mentioned copper pipe, iron (SGP), stainless steel (SU)
S), etc., and the inner diameter of each metal pipe (hereinafter referred to as a temperature control pipe) 2 is 7 to 13 mm, and the outer diameter / inner diameter ratio is 1.
The arrangement pitch of the temperature control pipes 2 was 1.5 to 3 times the inner diameter of the metal pipe, and the depth from the mold cavity surface to the outer peripheral upper surface of the temperature control pipes was 5 to 25 mm.

Using the molding die 1 thus manufactured, the cavity of the mold 1 is filled with a high-temperature molten resin and molded, and then the cooling medium sent from the mold temperature controller 4 is cooled. When the molten resin is cooled and solidified by passing it through the temperature control pipe 2, the optimal cooling temperature varies depending on the type of the resin, the shape and the size of the molded product, and the like. Needs to be adjusted. Conversely, before filling the high-temperature molten resin into the cavity of the mold 1, the heating medium sent from the mold heating temperature controller 5 is passed through the temperature control pipe 2 to adjust the temperature of the mold 1. Need to be done.

For this reason, as shown in FIG. 1, the temperature control pipe 4 is connected to the mold cooling temperature controller 4 or the mold heating temperature controller 5.
And a liquid such as oil or water controlled to a predetermined temperature by switching the switching valves 4a, 4b, 5a and 5b provided in the temperature controllers 4 and 5, respectively. A cooling medium or a heating medium (hereinafter, referred to as a heat medium) is circulated in the temperature control pipe 2 so that the mold temperature can be controlled to a desired temperature. Further, the connector 9 allows the mold 1 or the temperature control pipe 2 to be replaced with various molding dies 1 having different materials and pipe diameters. A thermocouple 11 for measuring the mold temperature is provided between the temperature control pipes 2 at the center of the molding mold 1. Symbol 3 is piping, 6
Denotes a flow control valve, 7 and 8 denote collecting pipes, 10 denotes a flow meter, and 11 denotes a thermocouple. The pipe 3 and the collecting pipes 7 and 8 are covered with a heat insulating material or the like to prevent heat radiation.

The operation of the present invention in the above configuration will be described. In FIG. 1, first, the switching valves 5a and 5b of the mold heating temperature controller 5 are opened (the switching valves 4a and 4b of the mold cooling temperature controller 4 are kept closed). Next, while watching the flow meter 10, the switching valve 5 on the discharge side of the temperature controller 5 for heating the mold is provided.
The opening degree of the flow control valve 6 is adjusted so that the Reynolds number of the heat medium discharged from a in the temperature control pipe 2 becomes 10,000. After the heating medium has passed through the flow meter 10, the piping 3
c, return to the mold heating temperature controller 5 from the return-side switching valve 5b via the collecting pipe 7, the temperature control pipe 2 (heating the molding die 1), the collecting pipe 8, and the pipes 3d and 3e. It has become. Note that the boundary between laminar flow and turbulent flow is when the Reynolds number is 5,000 to 6,000, and that turbulent flow occurs when the Reynolds number is 6,000 or more.
It is considered that a Reynolds number of 10,000 or more is desirable for increasing the temperature control efficiency of the mold.

In this experiment, when the molding die 1 is heated to a desired temperature by the heating medium flowing through the temperature control pipe 2, various factors affecting the mold heating time, for example, the heat flowing through the temperature control pipe 2 Medium flow state, temperature control pipe inner diameter,
Based on the theory of the outside diameter and inside diameter ratio of the temperature control pipe, the arrangement pitch of the temperature control pipe, the distance from the mold cavity surface to the outer peripheral upper surface of the temperature control pipe, the temperature control pipe material and the mold material, etc. An experiment was performed. as a result,
The results shown in FIGS. 2, 4, 5, 6, 7, and 8 were obtained. In particular, in the present embodiment, the mold material is selected based on the heat capacity (specific heat × density) rather than the conventional idea that the molding cycle time is shortened by using a material having a large temperature diffusion coefficient for the mold 1. It has been found that it is appropriate to shorten the mold heating time or the molding cycle time depending on the method.

This is because, assuming a perfect ideal state in which the laminar flow film of the heat medium flowing through the conventional temperature control pipe 2 is completely eliminated, the heat cycle of the mold 1 has a temperature diffusion coefficient [a mold diffusion coefficient]. Thermal conductivity / heat capacity (specific heat × density)] becomes dominant. For this reason, although it was considered that the heating cycle time becomes shorter as the temperature control diffusion coefficient of the mold becomes larger, in the present embodiment, the laminar flow film disappears even if the heat medium is considered to be a completely turbulent region. It has been found that the heat capacity is more dominant in the heat cycle of the mold 1 under such a semi-ideal condition. For this reason, in the present embodiment, an aluminum-based alloy having a small heat capacity was used as the material of the molding die 1. Incidentally, aluminum alloy (Al), copper alloy (Cu),
The heat capacity of the iron-based alloy (Fe) is Al <Cu <Fe, and among the three, the heat capacity of the aluminum-based alloy (Al) is the smallest, and conversely, the iron-based alloy (Fe) is the largest.
In comparison of only the temperature diffusion coefficient, Fe <Al <Cu
The copper alloy is the largest.

Next, when the heat medium flowing through the temperature control pipe 2 assumes a state with a small Reynolds number or a state with a large Reynolds number, the effect of the amount of heat held by the heat medium on the heating time of the mold 1 is theoretically described. Will be described. First, FIG.
In the state where the Reynolds number shown in (1) is small, the heat transfer resistance becomes large due to the thick laminar flow film B, and the temperature T
“a” greatly decreases to the temperature Tc at the contact point with the temperature control pipe 2. Further, the mold 1 is passed through the temperature control pipe 2.
The temperature Td decreases at the contact point between the temperature control pipe 2 and other factors such as the material and size of the temperature control pipe 2. This extremely low temperature T
The heat exchange between d and the mold 1 is dominantly determined by ΔT = Td−T ₀ . Here, since ΔT = Td−T ₀ is in a low state, the difference in the thermal conductivity due to the difference in the material of the temperature control pipe 2 and the change in the temperature Td due to the difference in the heat transfer distance due to the difference in the size of the temperature control pipe are small. , And consequently, ΔT = T
This greatly affects d-T _0, and therefore causes a large difference in the heating time of the mold 1.

On the other hand, in the state where the Reynolds number shown in FIG. 3 (2) is large, the laminar flow boundary film B becomes extremely thin, so that the temperature Tc 'at the contact point with the temperature control pipe 2 is kept high. Is done. Therefore, the temperature Td 'at the contact point with the mold 1 passing through the temperature control pipe 2 is in an extremely high state, and ΔT which is a dominant factor in heat exchange with the mold 1 is used.
T ′ = Td′−T ₀ is large, and as a result, the heating time of the mold 1 is short. Further, since ΔT ′ = Td′−T ₀ is high, the amount of change in temperature Td ′ due to the difference in the material of the temperature control pipe 2 and the size of the temperature control pipe 2 is ΔT ′ = T
Since it is extremely small with respect to d′−T ₀ , the influence on the heating time of the mold 1 is smaller than when the Reynolds number is small.

Further, by optimizing the dimensions of the temperature control pipe 2, for example, by optimizing the inner diameter and the outer diameter / inner diameter ratio of the temperature control pipe 2, the temperature at the contact point between the temperature control pipe 2 and the mold 1 is improved. The variation of Td 'is reduced, and the variation of the heating time of the mold 1 is reduced. Further, when the material of the temperature control pipe 2 is a copper alloy, when the temperature control pipe 2 is cast with an aluminum melt, the temperature control pipe 2 and the mold 1 are left untreated by the erosion prevention treatment. It is possible to prevent the influence of a very large heat transfer resistance due to the heat insulating layer of the bonding metal in advance.

A verification experiment was performed based on the above-described concept, and the experimental results shown in FIGS. 2, 4, 5, 6, 7, and 8 were obtained. First, as shown in FIG. 2, when the material of the temperature control pipe 2 cast in the mold is changed to stainless steel, an iron-based alloy and a copper-based alloy, respectively, The effect of the change in the Reynolds number on the heating time of the molding die 1 was tested under the following conditions. <Experiment conditions> Mold material; Aluminum alloy (AC4C) Dimensions: Width 100 x length 200 x thickness 40 mm Pipe for temperature control of cast-in material Material: Copper, stainless steel, iron (SGP) Inner diameter; 7-13 mm Pitch between pipes; 25 mm Depth from mold cavity surface to temperature control pipe outer peripheral upper surface; 10 mm Heat medium type; commercially available heat medium oil Temperature: 180 ° C.

As a result of the experiment, when the Reynolds number forming the turbulent flow region is 6,000 or more, even if stainless steel, iron (SGP), or copper is used for the temperature control pipe 2, the predetermined temperature of the molding die 1 is increased. The heating time difference gradually disappeared, and almost coincided at a Reynolds number of 10,000. On the other hand, when the Reynolds number is 6,000 or less, the heating time of the mold 1 varies depending on the material of the temperature control pipe 2, and the copper <
The heat transfer from the heat medium becomes difficult in the order of iron <stainless steel, and the difference in the material of the temperature control pipe 2 appears remarkably.
This is in line with the idea described in. For the reasons described above, if the Reynolds number is set to 6,000 to 12,000, the temperature control pipe 2 can be made of an iron or stainless steel pipe which does not require erosion prevention treatment. And the heating time is not much different.

FIG. 4 shows a case in which heat mediums of different temperatures are respectively flown into the temperature control pipe 2 cast in the mold.
The results of an experiment conducted on the effect of the change in the inner diameter of the temperature control pipe 2 on the heating time of the molding die 1 under the following conditions are shown. <Experiment conditions> Mold material; Aluminum alloy (AC4C) Dimensions: Width 100 x Length 200 x Thickness 40 mm Cast-in temperature control pipe Material: Stainless steel (SUS) Inner diameter: 3 to 14 mm Pitch between pipes: 25 mm Mold cavity Depth from the surface to the top surface of the outer periphery of the temperature control pipe; 10 mm Reynolds number (Re) 10,000 (-) Heat medium type; commercially available heat medium oil Temperature; 180 ° C and 200 ° C The Reynolds number (Re) is It was calculated by the formula.

[0024]

## EQU1 ## Re = d, v / μ (-)

Here, d is the pipe inner diameter (mm), v is the heat medium flow rate (m / sec), and μ is the kinematic viscosity coefficient (m
² / sec).

As a result of the experiment, as the inner diameter of the temperature control pipe 2 became larger, the heating time until the molding die 1 was heated to a desired temperature tended to become shorter. This is because the temperature Ta of the heat medium flowing in the temperature control pipe 2 is changed by the laminar flow film B,
The factor of the heat transfer area passing through the inside of the temperature control pipe 2 when transferring heat to the mold 1 via the temperature control pipe 2 (here, the inner diameter of the temperature control pipe 2, that is, the inner peripheral area of the temperature control pipe 2).
The larger the heat transfer area (ie, the larger the inner diameter of the temperature control pipe 2), the shorter the heating time of the mold 1 is.

However, when the heat medium temperature is 180 ° C. and 2 ° C.
The inner diameter of the temperature control pipe 2 is 7
mm or more, the mold heating time gradually decreases,
It is confirmed that there is almost no difference in the mold heating time at 13 mm or more, which is consistent with the concept described in FIG. 3 that the heating time difference of the mold 1 is reduced by optimizing the temperature control pipe 2. Here, when the inner diameter of the temperature control pipe 2 is 7 mm or less, a mold heating time difference occurs, and the mold heating time becomes longer. However, even if the inner diameter of the temperature control pipe 2 is 7 mm or less, it is conceivable to increase the number of the temperature control pipes 2 in order to obtain a desired mold temperature in a short time. The mounting process of the adjusting pipe 2 becomes complicated. In addition, the pressure loss in the temperature control pipe 2 becomes extremely large, and the Reynolds number of the heat medium is reduced to 10,000.
In order to maintain the temperature, the mold heating temperature controller 5 and the auxiliary equipment are enlarged.

Conversely, when the inner diameter of the temperature control pipe 2 is 13 mm or more, there is almost no difference in the heating time of the molding die 1, but in order to maintain the Reynolds number at 10,000, the heat flowing through the temperature control pipe 2 is required. The medium flow rate increases, and large-sized equipment is required for the mold heating temperature controller 5 and the accompanying equipment. As described above, the Reynolds number is set to 6,0 for the reason described above.
When it is set to 00 to 12,000, it is desirable that the inner diameter of the temperature control pipe 2 is in the range of 7 to 13 mm.

Next, as shown in FIG.
The effect of the change in the outer diameter / inner diameter ratio on the mold heating time was tested under the same experimental conditions as in FIG. As a result of the experiment, although the heating time until the molding die 1 was heated to the desired temperature tended to increase as the outer diameter / inner diameter ratio of the temperature control pipe 2 increased, the temperature control pipe 2
When the outside diameter / inner diameter ratio is in the range of 1.2 to 1.7, the difference in the heating time of the mold 1 is extremely small, and by appropriately dimensioning the temperature control pipe 2, the heating time of the mold 1 is reduced. Is consistent with the idea described in FIG.

In FIG. 5, when the outside diameter / inside diameter ratio of the temperature control pipe 2 is 1.2 or less, the heating time until the molding die 1 is heated to a predetermined temperature is shortened. Because of the thin wall thickness, it is melted down during insert casting,
It is difficult to form holes for heating and cooling medium passages,
There are restrictions on production. Even if the surface of the temperature control pipe 2 is treated to prevent erosion, such as a heat-resistant coating agent, to prevent the temperature control pipe 2 from being melted, the temperature control pipe 2 may not be sufficiently hot during casting due to lack of strength. The heat control pipe 2 is deformed, making it difficult to form and maintain a hole for a heating or cooling medium passage at a desired location. In addition, a heat-insulating layer coated with heat is provided between the heat control pipe 2 and the mold 1. Remains and reduces heat transfer efficiency.

Conversely, when the outside diameter / inside diameter ratio of the temperature control pipe 2 is 1.7 or more, the heating time until the molding die 1 is heated to the predetermined temperature is long. Also, as the pipe outer diameter / inner diameter ratio of the temperature control pipe 2 increases,
That is, since the thickness of the temperature control pipe 2 is too large, it becomes difficult to process the temperature control pipe 2 into a desired shape.
It becomes impossible to form the heating / cooling medium passage hole along the mold cavity surface. For the reasons described above, when the Reynolds number is set to 6,000 to 12,000, the outer diameter / inner diameter ratio of the temperature control pipe 2 is 1.2 to 1.
It is desirable to use one in the range of 7.

Next, in FIG. 6, the influence of the change in the arrangement pitch of the temperature control pipes 2 on the mold heating time will be described.
The results of an experiment conducted under the following conditions are shown. <Experiment conditions> Mold material; Aluminum alloy (AC4C) Dimensions: Width 100 x Length 200 x Thickness 40 mm Cast-in temperature control pipe Material: Stainless steel (SUS) Inner diameter: 7 to 13 mm Pitch between pipes: Metal pipe inner diameter 1.5 to 4 times Depth from the mold cavity surface to the outer peripheral upper surface of the temperature control pipe; 10 mm Reynolds number (Re) 10,000 (-) Heat medium Type: Commercial heat medium oil Temperature: 180 ° C

As a result of the experiment, when the arrangement pitch of the temperature control pipes 2 is 1.5 times or less the inner diameter of the temperature control pipes 2, the number of the temperature control pipes 2 is unnecessarily increased. Overlay makes casting impossible. In addition, the gap between the temperature control pipes 2 is small in machining such as a vent hole to penetrate from the back surface of the mold 1 to the cavity surface of the mold, and machining is difficult. Furthermore, since the temperature control pipes 2 are too close to each other, poor running of the metal near the temperature control pipe 2 is likely to occur particularly in cast-in casting, and as a result, it is difficult to obtain a sound mold 1. On the other hand, if it is three times or more, the number of pipes necessary for controlling the temperature of the mold 1 becomes insufficient, and as a result, the heating time of the mold 1 becomes longer.

FIG. 7 shows the results of an experiment conducted on the effect of the change in the distance from the mold cavity surface to the outer peripheral upper surface of the temperature control pipe 2 on the mold heating time under the following conditions. <Experiment conditions> Mold material; Aluminum alloy (AC4C) Dimensions: Width 100 x Length 200 x Thickness 40 mm Cast-in temperature control pipe Material: Stainless steel (SUS) Inner diameter: 7 to 13 mm Pitch between pipes: 25 mm Mold cavity Distance to surface: 5 to 25 mm Reynolds number (Re) 10,000 (-) Heat medium type: Commercial heat medium oil Temperature: 180 ° C

As a result of the experiment, when the distance from the mold cavity surface to the outer peripheral upper surface of the temperature control pipe 2 is 5 mm or less, the amount of heat held by the heat medium flowing in the temperature control pipe 2 is uniform throughout the mold 1 in the middle. It flows to the mold cavity surface side without being heated, causing local heating. Conversely, if the thickness is 25 mm or more, the thickness of the mold cavity is unnecessarily increased, and as a result, the heating time of the mold 1 is prolonged.

FIG. 8 shows an experiment conducted on the molding cycle time depending on the material of the molding die 1 under the following conditions. <Experimental conditions> Mold for molding A spoiler mold for producing an automotive spoiler was used. Material: This example (aluminum alloy AC4C) Comparative example (1) (copper alloy) Comparative example (2) (iron-based alloy) Dimensions: width 300 x length 1400 x thickness 50 mm Cast-in temperature control pipe Material: stainless steel Dimensions: Outer diameter / 12 x wall thickness 1.5 mm Pitch between pipes: 25 mm Reynolds number (Re) 10,000 (-) Cooling medium and heating medium Type: Commercial heating medium oil Cooling medium temperature; 40 ° C Heating medium temperature; 200 ° C

FIG. 8 shows the experimental results. As is clear from FIG. 8, in this embodiment, the use of the aluminum alloy (AC4C) having a small heat capacity enables heating and cooling of the mold 1 in a short molding cycle time. In addition, in the case of the copper-based alloy used in Comparative Example (1), the heat capacity was smaller and the molding cycle time was shorter than the iron-based alloy used in Comparative Example (2). This is because in the present invention, as long as the laminar film of the heat medium flowing through the temperature control pipe 2 exists, the heat cycle of the mold 1 is dominated by the heat capacity rather than the temperature diffusion coefficient. Consistent with the idea of
From the above, aluminum alloy> copper alloy> iron-based alloy in the order of smaller heat capacity, and the result was that the molding cycle time became shorter.

In this example, based on the various findings obtained from the above experiments, the superiority of this example and the comparative example shown in Table 1 were compared and studied.

[0039]

[Table 1]

As is clear from Table 1, when the reference value of Comparative Example 2 was set to 1, the superiority of the molding die 1 of this example was proved in all respects. In this embodiment, the temperature of the heat medium is set to 180 to 200 ° C., but if the temperature is 180 ° C. or less, the molding cycle time becomes longer. From 180 to 200
C is desirable. In the present embodiment, FIGS.
As shown in FIGS. 6 and 7, various experiments were conducted on the effects of the temperature control pipe inner diameter, the temperature control pipe outer diameter / inner diameter ratio, and the Reynolds number on the heating time of the molding die 1. Regarding the effect on the cooling time of the mold 1, almost the same experimental results as the heating time were obtained.

[0041]

As is apparent from the above description, according to the present invention, the temperature of the mold is adjusted by flowing a heating or cooling medium made of a liquid through a plurality of temperature control tubes penetrating the mold. in mold method temperature control mold key
The Reynolds number of the heating or cooling medium flowing through the Yabiti surface was cast Guruma along the temperature control pipe 6,000～1
A molding die having a heating or cooling medium passage hole near a cavity of the die by casting a metal pipe inside the die; An aluminum alloy is used as a base material of a molding die, and an iron-based material is used for the metal pipe. The dimensions of the metal pipe are 7 to 13 mm in inner diameter, the outer diameter / inner diameter ratio is 1.2 to 1.7, The arrangement pitch of the metal pipes is 1.5 to 3 times the inner diameter of the metal pipe, and the depth from the mold cavity surface to the outer surface of the metal pipe is 5 to 25.
By setting mm, the heating and cooling time of the mold cavity surface is reduced, the molding cycle is significantly reduced, and the productivity is improved.

[Brief description of the drawings]

FIG. 1 is a temperature control piping diagram of a molding die.

FIG. 2 is a diagram showing the relationship between Reynolds number and mold heating time.

FIG. 3 is an explanatory diagram for heating a mold by a heat medium.

FIG. 4 is a diagram illustrating a relationship between an inner diameter of a temperature control pipe forming a heating / cooling medium passage hole and a heating time of a mold.

FIG. 5 is a diagram showing a relationship between an outer diameter / inner diameter ratio of a temperature control pipe and a heating time of a mold.

FIG. 6 is a diagram illustrating a relationship between an arrangement pitch of temperature control pipes and a mold heating time.

FIG. 7 is a diagram showing the relationship between the distance from the mold cavity surface to the upper surface of the temperature control pipe and the mold heating time.

FIG. 8 is a relationship diagram between a molding die material and a molding cycle time.

FIG. 9 is a front view of a mold using another piping method for the temperature control pipe according to the embodiment of the present invention.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 Molding die 2 Casting metal pipe (temperature control pipe) 3 (3a, 3b, 3c, 3d, 3e, 3f, 3g) Piping 4 Mold cooling temperature controller 5 Mold heating temperature controller 6 Flow control valve 7, 8 Collecting pipe 9 Connector 10 Flow meter 11 Thermocouple

Continuation of the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B22D 27/04 B22C 9/06 B29C 45/00

Claims (2)

(57) [Claims] 1. A mold process temperature control which is adapted to a plurality of temperature control pipes that penetrated the mold by circulating a heating or cooling medium consisting of liquid to adjust the mold temperature, the mold calibration
The was insert cast along the Activity surface Reynolds number of heating or cooling medium flowing through the temperature control pipe 6,000～12,
A method for controlling the temperature of a molding die, wherein the temperature is controlled as 000. 2. A molding die provided with a heating or cooling medium passage hole in the vicinity of a cavity of the die by casting a metal pipe inside the die. An aluminum alloy is used for the material, and an iron-based material is used for the metal pipe. The dimensions of the metal pipe are 7 to 13 mm in inner diameter, the ratio of outer to inner diameter is 1.2 to 1.7, and the arrangement pitch of the metal pipe is A molding die having a diameter of 1.5 to 3 times the inner diameter of the metal pipe and a depth of 5 to 25 mm from the die cavity surface to the outer peripheral upper surface of the metal pipe.