JPH11268081A - Mold for plastic molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently uniformly cool by providing a heat transfer means for conducting a heat radiated from a resin in a cavity from an insert of a mold for forming the cavity out of the mold to dissipate the heat. SOLUTION: Detecting elements of a temperature sensor 15 and pressure sensor 16 of one set are provided near a cavity 5 of a fixed insert 3 and a movable insert 4. The sensors 15, 16 respectively detects a temperature and a pressure of a resin 16 in the cavity 5. A heat transfer means 14 is provided in the insert 4. The means 14 is constituted by a heat pipe having excellent heat transferability, penetrated through the mold 2, one end of which is disposed near the cavity 5 and the other of which is inserted into a radiating block 6 provided in contact with a surface of the mold 2. Heat radiated from a resin 19 in the cavity 5 is efficiently conducted to a radiating block 6 by using the pipe. Thus, even if a distance to the surface of the mold 2 is long, uniform cooling can be efficiently conducted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding die for a plastic molded article having a complicated shape and an unbalanced thickness distribution.

[0002]

2. Description of the Related Art In general, as a method for producing a plastic molded product, a molten resin is injected and filled into a cavity of a molding die maintained at a constant temperature, and then cooled to solidify the resin, thereby molding the molded product. Was. During the cooling, a heat amount corresponding to the resin volume in the cavity is radiated. For this reason, if the cavity shape is complicated and the wall thickness is extremely unbalanced, the cooling and solidification will be partially delayed, and the shrinkage of each part of the molded product will vary, causing deterioration in shape accuracy and optical distortion. Become. Therefore, conventionally, the mold temperature is raised above the glass transition point to increase the resin flow, the molten resin is injected into the cavity, and then the mold is cooled to the heat deformation temperature or lower and the molded product is taken out. Thereby, the transferability is improved, and a device for reducing the temperature difference between the surface of the molded article and the inside thereof is devised. In particular, in the case of molded products requiring high precision, such as lenses, a method of gradually cooling the mold is employed in addition to raising and lowering the mold temperature.

[0003] Conventional mold cooling methods include, for example,
A method of circulating cooling water through a hole formed in a mold as described in JP-A-1-200925 or a fluid passage for cooling as described in JP-A-7-52161 In this method, a liquid and a gas are alternately and continuously circulated. However, in such a method, it is necessary to design an optimal heat medium passage in correspondence with the heat radiation amount distribution from the resin in the cavity accurately, and to accurately evaluate the heat radiation amount distribution and the heat medium passage in the mold. It is difficult to make the heat radiation amount distribution uniform due to restrictions on the processing space. Further, in order to design a heat medium passage accurately corresponding to the heat radiation amount distribution, it is necessary to determine a cooling condition and a molding cycle by trial and error every time a cavity shape, a resin thickness, a resin material, and the like are changed. And there is a problem that work efficiency is poor.

Accordingly, the same applicant as the present application uses a synthetic resin film adhered to the surface of the mold or a thermal emissivity adjusting means comprising a painted surface to adjust the surface of the mold during cooling according to the volume of the resin in the cavity. A simple molding method and a metal mold for partially changing the thermal emissivity of the glass have already been proposed. This technology can be applied to molded products with unbalanced thickness distribution.
This is effective for keeping the cooling rate of each part uniform and suppressing the deterioration of shape accuracy and the occurrence of optical distortion.

[0005]

In the above-mentioned prior art, heat transfer from the resin in the cavity is performed by heat conduction. Therefore, depending on the shape or size of the molded product, from the input piece forming the cavity to the surface of one of the molds. When the distance is longer than the distance to the other mold surface, there is a problem that heat transfer to the mold surface takes time and the molding cycle becomes longer.

SUMMARY OF THE INVENTION An object of the present invention is to improve such a problem, and when molding a molded article having a complicated shape due to an unbalanced thickness distribution of the resin in the cavity, from the input piece forming the cavity to the surface of the mold. Even if the distance is long, the heat from the resin in the cavity can be more efficiently dissipated, and each part can be cooled uniformly, providing a molding die for plastic molded products suitable for shortening the molding cycle. Is to do.

[0007]

In order to achieve the above object, a molding die for a plastic molded product of the present invention is provided with a cavity for integrally joining and injecting and filling a molten resin, and then solidifying by cooling. In a molding die for forming a plastic molded product, a heat transfer means for conducting and radiating heat radiation from the resin in the cavity from an input portion of the molding die forming the cavity to the outside of the mold is provided. Features.

In order to achieve the above object, a molding die for a plastic molded product according to the present invention is configured to be integrally joined to form a cavity, and a resin base material having a substantially final shape is formed in the cavity. After the mold is inserted and clamped, the resin base material is heated to generate a resin internal pressure, and then cooled and solidified in a molding die of a plastic molded product, which radiates heat from a portion where the volume of the resin in the cavity is large. A first heat transfer means that conducts and radiates from the input portion of the molding die forming the cavity to the outside of the die, and radiates heat from a small volume resin portion in the cavity to form the cavity. And a second heat transfer means for conducting and diverging from the entrance portion of the forming die to the outside of the die.

Further, in order to achieve the above object, a molding die for a plastic molded product of the present invention is integrally formed with a plastic molding for injecting and filling a molten resin and then forming a cavity for solidification by cooling. A molding die provided in the vicinity of the cavity, for detecting temperature and pressure of the resin in the cavity; and A heat transfer means provided through the molding die to conduct heat radiation from the resin in the cavity to the outside of the die;
A heat radiation adjusting means connected to the heat transfer means and provided in contact with the mold surface, and adjusting a heat radiation amount from the resin in the cavity based on detection information of the detection means. I do.

In order to achieve the above object, a molding die for a plastic molded product according to the present invention is configured to be integrally joined to form a cavity, and a resin base material having a substantially final shape is formed in the cavity. After the mold is inserted and clamped, the resin base material is heated to generate a resin internal pressure, and thereafter, a molding die for a plastic molded product that is cooled and solidified. The molding die is provided near the cavity. Detecting means for detecting pressure; and a portion provided from the entrance of the molding die forming the cavity to the outside of the mold, and penetrating the molding die, and having a large volume of resin in the cavity. A first heat transfer means for conducting heat radiation from the mold to the outside of the mold and radiating the heat;
And a heat transfer means connected to the heat transfer means and provided in contact with the surface of the mold, and adjusts a heat release amount from the resin in the cavity based on detection information of the detection means. And a heat radiation adjusting means.

Further, the heat transfer means has a heat pipe, one end of the heat pipe is located near the cavity, and the other end is inserted into the heat radiation adjusting means. I do. Further, the heat pipe may be configured such that a diameter of the heat pipe is different depending on a distance from an input portion of the molding die forming the cavity to a mold surface and a volume of resin in the cavity. Features.

Further, the heat radiation adjusting means has a space through which a gas as a cooling medium circulates, and a plurality of ventilation holes formed in a surface portion covering the space, so that the gas flow rate and the gas flow can be controlled. The heat radiation amount from the resin is adjusted by selectively sealing the pores. Further, the heat radiation adjusting means has a circulation path for circulating a liquid as a cooling medium, and is configured to adjust a heat radiation amount from the resin according to a temperature and a flow rate of the liquid. .

Further, on the surface of the heat radiation adjusting means,
It is characterized by having thermal emissivity adjusting means including a synthetic resin film surface, a paint surface, and a finished surface.

[0014]

An embodiment of the present invention will be described below with reference to the drawings. First Embodiment In FIG. 1, a cavity forming member, that is, a fixed input piece 3 and a movable input piece 4 are provided inside a fixed mold (molding mold) 1 and a movable mold (molding mold) 2. The cavity 19 has a constant volume on the inner peripheral surface of the cavity forming portion, and the thickness distribution of the resin 19 in the cavity is unbalanced and unevenly distributed to the fixed input piece 3 side, to the surface of the movable mold 2. Is formed, and a mirror surface is formed on an inner peripheral surface forming the cavity 5. Further, a sprue is formed in the fixed die 1, and the resin melted from the molding nozzle 18 of the injection molding machine is injected and filled into the cavity 5 through the sprue. A pair of temperature sensors 15 (= detection means for detecting temperature) and pressure sensors 16 are provided near the cavities of the fixed input piece 3 and the movable input piece 4, respectively.
(= Detection means for detecting pressure) are provided, which are configured to detect the temperature and pressure of the resin 19 in the cavity 5.

The movable transfer piece 4 has a heat transfer means 14 therein.
Is provided. The heat transfer means 14 is composed of, for example, a heat pipe having excellent heat conductivity, the heat pipe penetrating the molding die 2, one end of which is located near the cavity 5, and the other end thereof. A heat radiation block 6 (= radiation adjusting means) provided in contact with the surface of the movable mold 2
Is inserted inside. This is because the resin 1 in the cavity 5
Since the distance from the surface of the movable mold 2 to the surface of the movable mold 2 is long, the cavity 5
This is because the heat radiation from the resin 19 inside is efficiently transmitted to the heat radiation block 6 so that uniform cooling is performed in a shorter time. That is, when the temperature in the vicinity of the cavity is higher than that of the heat radiation block 6, the heat radiation in the vicinity of the cavity continues to be radiated into the heat radiation block 6 through the heat pipe, so that the distance to the surface of the movable mold 2 is long. Regardless, uniform cooling is performed on the surfaces of the fixed mold 1 and the movable mold 2. Further, a plurality of heat radiation fins 14a are attached to the other end of the heat pipe, thereby promoting a heat radiation effect in the heat radiation block 6.

The heat radiation block 6 is provided with a movable mold 2.
And is connected to the heat transfer means 14 and uses air as a cooling medium as shown in FIGS. A space 6a is provided in the heat radiation block 6 so that air can easily circulate, and minute air holes 6 are formed on all surface portions (four surfaces) other than in contact with the movable mold 2 and the temperature control plate 8.
b is drilled multiple times. This ventilation hole 6b is provided with a sealing material 6c.
Thus, it is possible to finely adjust the amount of heat radiation from the heat transfer means 14 by combining with the air volume adjustment by the air volume adjusting device 20. In addition, a control unit (not shown) of the air volume adjusting device 20
Controls to change the rotation speed of the blower fan based on the detection information of the temperature sensor 15 and the pressure sensor 16 arranged near the cavity 5. For example, when cooling the resin 19 filled in the cavity 5, the cavity 5
The amount of air blown from the heat radiation block 6 is increased so that the heat radiation on the movable mold 2 side is promoted more than on the fixed mold 1 side. Alternatively, the amount of air to be blown is changed according to the change in the resin material constituting the resin 19 in the cavity.

Temperature control plates 7 and 8 are provided on the outer periphery of the fixed mold 1 and the heat radiation block 6, respectively. Inside the temperature control plates 7 and 8, heaters and cooling pipes are provided, respectively. (Not shown). The heater is a rod-shaped heater, the cooling pipe is a pipe for flowing water or air or water and air at a predetermined mixing ratio, and the fixed mold 1 is heated and cooled by the heater and the cold air pipe. You. In addition, movable mold 2
Is heated and cooled by the heater and the cool air pipe through the heat radiation block 6.

Die plates 11 and 12 are attached to the temperature plates 7 and 8 via heat insulating plates 9 and 10, and a mold clamping mechanism 13 is attached to the die plate 12 side. The mold clamping mechanism 13 moves the die plate 12, the heat insulating plate 10, the heat radiation block 6, and the movable mold 2 relative to the die plate 11, the heat insulating plate 9, and the fixed mold 1 in the horizontal direction in the drawing. 5 is opened and closed, and the movable mold 2 is pressed against the fixed mold 1 to generate a predetermined mold clamping force.

Further, a synthetic resin film 17a as a heat radiation rate adjusting means 17 is adhered to the surface of the heat radiation block 6, and this film 17a determines the heat emissivity of the surface of the heat radiation block 6 to form the cavity 5. It is changed according to the distance from the entrance pieces 3 and 4 to the surface of the molding die 2 and the volume of the resin 19 in the cavity 5. Here, the reason for attaching the film 17a will be described. For example, FIG. 4 shows the cooling rate when comparing a case where a black film is attached to iron or aluminum with a length and width of 60 mm × 60 mm and a height of 180 mm and a case where no film is attached.
From FIG. 4, it can be seen that the cooling rate is higher when the black film is attached than when it is not attached. FIG. 5 shows the thermal emissivity of each color film when the thermal emissivity of the black film is set to 1. It can be seen from FIG. 5 that the thermal emissivity differs depending on the color of the film. In this embodiment,
Such a synthetic resin film 17a is provided to the heat radiation block 6.
Is attached to the surface of the heat radiation block 6 so that the heat emissivity of the surface of the heat radiation block 6 becomes larger. Specifically, a black film is adhered to the surface (four surfaces) of the heat radiation block 6 with a predetermined thickness. If the resin material is different even if the cavities 5 have the same shape, the color and thickness of the film may be changed and the film may be adhered.

Further, as other thermal emissivity adjusting means,
By forming a fine uneven shape on the surface of the heat radiating block 6 and adjusting the surface roughness with the uneven shape, the thermal emissivity of the heat radiating block surface can be reduced by the input pieces 3 forming the cavity 5.
The distance may be changed according to the distance from the mold 4 to the surface of the molding die 2 and the volume of the resin in the cavity 5. In the present embodiment, the surface roughness is set so that the heat emissivity of the surface of the heat radiation block 6 becomes larger. Specifically, the surface (four surfaces) of the heat radiation block 6 is formed roughly. If the resin material is different even in the cavity 5 having the same shape, the surface roughness may be changed. The reason for this is that a mirror with a smooth surface, such as a mirror surface, has a high reflectance and a low thermal emissivity.

Next, a method for molding a plastic molded article according to the present embodiment will be described. First, after the mold is clamped by the mold clamping mechanism 13, the temperature of the molds 1 and 2 is raised to a temperature equal to or higher than the glass transition point of the resin by a heater (not shown) to increase the resin flow. The cavity 5 is filled with molten resin from the nozzle 18 through a sprue.

Next, the cooling pipes (not shown) of the temperature control plate 7, the cooling pipes (not shown) of the temperature control plate 8, and the air circulating in the heat radiating block 6 cause the mold 1, 1.
By cooling 2, the resin 19 is cooled to a temperature equal to or lower than the heat deformation temperature. At this time, since the temperature in the vicinity of the cavity is higher than that on the heat radiation block 6 side, the heat radiation from the resin 19 continues to be transmitted to the heat radiation block 6 through the heat transfer means (heat pipe) 14. On the other hand, in the heat radiating block 6, the amount of heat radiated from the resin 19 is adjusted by controlling the number of rotations of the fan by the air volume adjusting device 20 based on the detection information of the temperature sensor 15 and the pressure sensor 16 near the cavity. Fine-tune. Further, the heat radiation effect in the heat radiation block 6 is promoted by the plural heat radiation fins 14a attached to the heat pipe end. Thus, the heat radiation in the vicinity of the cavity continues to be dissipated in the heat radiation block 6 through the heat pipe, and uniform cooling is performed on the surfaces of the fixed mold 1 and the movable mold 2. The optimum thermal emissivity of the film 17a is set according to the distance from the input pieces 3 and 4 forming the cavity 5 to the surface of the molding die 2 and the volume of the resin 19 in the cavity 5. In addition, efficient cooling is performed not only in the heat dissipation block 6 but also from the surface of the heat dissipation block 6. Therefore, even if the thickness distribution is an unbalanced plastic molded product and the distance from the input pieces 3 and 4 forming the cavity 5 to the surface of the molding die 2 is long, the cooling rate in each part is uniform. become,
An efficient cooling process shortens the molding cycle.

Next, the mirror surface is transferred to the resin 19, and after the cooling and solidification of the resin 19, the mold is opened by the mold clamping mechanism 13 to take out the molded product from the cavity 5. According to the present embodiment, from the vicinity of the cavity where the distance from the input pieces 3 and 4 forming the cavity 5 to the surfaces of the molding dies 1 and 2 extends to the outside of the mold on the longer side,
A heat transfer means 14 including a heat pipe is provided, and in a cooling step, heat release from the resin 19 conducted into the heat dissipation block 6 through the heat transfer means 14 is performed based on detection information of the temperature sensor 15 and the pressure sensor 16. Since the air is diverged by finely controlling the amount of air blown in the heat radiating block 6, for example, the thickness distribution is unbalanced and is unevenly distributed to the fixed input piece 3 side, and is movable from the input pieces 3 and 4 forming the cavity 5. Even when the distance to the surface of the mold 2 is longer, uniform and efficient cooling in each part can be realized. Therefore, it is possible to suppress the deterioration of the shape accuracy and the occurrence of optical distortion, to obtain a high-precision plastic molded product, and to shorten the molding cycle. Further, also with the film 17a, efficient cooling from the surface of the heat radiating block 6 is easily performed by the preset optimum heat emissivity,
Shrinkage of each part can be made uniform.

In the present embodiment, the heat radiation block 6 is disposed between the movable mold 2 and the temperature control plate 8, but depending on the arrangement of the cavities 5 in the molding dies 1 and 2,
It may be configured to be mounted between the molding die 1 and the temperature control plate 7 or on another die surface. This makes it possible to realize uniform and rapid cooling as a whole even for a molded product having a complicated shape and an unbalanced thickness distribution.

[Second Embodiment] In FIG.
Inside the fixed mold (molding mold) 1 and the movable mold (molding mold) 2, a cavity forming member, that is, a fixed input piece 3 and a movable input piece 4, are provided. It has a constant volume and the plastic matrix (=
The thickness distribution of the resin base material 21 is unbalanced, the center of the cavity 5 is thin and the cross section is thick at both ends, and the distance from the ends to the surface of the movable mold 2 is The cavity 5 is formed so as to be longer than the distance from the center to the surface of the movable mold 2. A mirror surface is formed on the inner peripheral surface forming the cavity 5. Into the cavity 5, a resin base material 21 previously formed into a substantially final shape by an injection molding machine (not shown) is inserted. In the vicinity of the cavity on the fixed entry piece 3 side, detection elements of three pairs of temperature sensors 15 (= detection means for detecting temperature) and pressure sensors 16 (= detection means for detecting pressure) are provided. These are configured to detect the temperature and pressure at the center and both ends of the resin base material 21 in the cavity 5.

Further, a heat transfer means 14 is provided in the vicinity of the cavity on the movable input piece 4 side. This heat transfer means 14
For example, the heat pipes 14a (= first heat transfer means) and heat pipes 14b (= second heat transfer means) having excellent thermal conductivity and different diameters are provided. One end of each of 14a and 14b is located near both ends and the center of the cavity 5, and the other end is
Radiation block 6 (= radiation adjusting means) provided in contact with
Is inserted inside. This is because the volume of the resin base material 21 in the cavity 5 is small at the center of the cavity 5 and large at both ends, so that the heat pipes 14a and 14
This is because uniform cooling can be performed in a shorter time by partially changing the heat radiation amount to the heat radiation block 6 in b.
That is, the heat pipes 14a having a large diameter are provided at both ends of the thick wall where the volume of the resin base material 21 in the cavity is large so as to promote the heat radiation near the both ends of the cavity from the center.
And a small-diameter heat pipe 14b is arranged in the center of the thin wall having a small volume so as to suppress the heat radiation near the center of the cavity. With this configuration, when the temperature in the vicinity of the cavity is higher than the inside of the heat radiation block 6, the heat radiation from the resin base material 21 in the cavity is larger at both ends than the heat radiation at the center. As a result, since the heat is continuously radiated through the heat pipes 14a and 14b into the heat radiation block 6, uniform cooling is performed in each part.

The heat radiation block 6 is provided with a movable mold 2.
And is connected to the heat transfer means 14 and uses a liquid such as water as a cooling medium as shown in FIG.
In the heat radiation block 6, a circulation path 6d for circulating the cooling water is provided. The control unit (not shown) of the temperature control device 6e controls the temperature and the flow rate of the cooling water based on the detection information of the temperature sensor 15 and the pressure sensor 16 arranged near the cavity 5. For example,
When cooling the resin base material 21 inserted into the cavity 5, the temperature and flow rate of the cooling water in the heat radiation block 6 are set so that heat radiation at both ends proceeds more than the center of the cavity 5. Alternatively, the resin base material 2 in the cavity
The setting of the temperature and the flow rate of the cooling water is changed in accordance with the change of the resin material constituting 1. By circulating the cooling water in this way, it is possible to cope with a case where a larger heat radiation amount adjustment is required.

Temperature control plates 7, 8 are provided on the outer periphery of the fixed mold 1 and the heat radiation block 6, respectively, and inside the temperature control plates 7, 8, heaters 7a, 8a and Cooling pipes 7b and 8b are provided. The heaters 7a and 8b are rod-shaped heaters, and the cooling pipes 7b and 8b are pipes for flowing water or air or water and air at a predetermined mixing ratio. Fixed mold 1
Is heated and cooled by the heater 7a and the cooling pipe 7b, and the movable mold 2 is heated and cooled by the heater 8a and the cooling pipe 8b through the heat radiation block 6.

Further, die plates 11 and 12 are attached to the temperature control plates 7 and 8 via heat insulating plates 9 and 10, and a mold clamping mechanism 13 is attached to the die plate 12 side. The mold clamping mechanism 13 moves the die plate 12, the heat insulating plate 10, the heat radiating block 6, and the movable mold 2 with respect to the die plate 11, the heat insulating plate 9, and the fixed mold 1 in the vertical direction in the drawing to form a cavity. 5 is opened and closed, and the movable mold 2 is pressed against the fixed mold 1 to generate a predetermined mold clamping force.

Further, on the surface of the heat radiation block 6, a paint surface 17b, which is a heat radiation rate adjusting means 17, is formed. FIG. 8 shows the thermal emissivity of each color when the thermal emissivity of the black paint is set to 1. As can be seen from FIG. 8, since the thermal emissivity differs depending on the color of the paint, the radiation block 6
A paint is applied to the surface of the heat radiation block 6 so that the heat emissivity of the surface of the heat radiation block 6 changes entirely or partially according to the volume of the resin base material 21 at the center and both ends in the cavity 5. In the present embodiment, the black paint is applied to the surface (four surfaces) of the heat radiation block 6 with a predetermined thickness to form the paint surface 17b. Further, the thermal emissivity of two surfaces (both left and right sides in FIG. 6) of the heat radiation block 6 facing the large-diameter heat pipe 14a is different from that of the two surfaces of the heat radiation block 6 facing the small-diameter heat pipe 14b (in FIG. 6). The color and thickness of the paint may be changed so as to be larger than the thermal emissivity of both front and rear sides. When the resin material of the resin base material 21 is changed even in the cavity 5 having the same shape, the color of the paint may be changed and applied.

Next, a method of molding a plastic molded article according to the present embodiment will be described. First, the molds 1 and 2 are opened by the mold clamping mechanism 13, the resin base material 21 having a substantially final shape is inserted into the cavity 5, and the mold is clamped. Then, the temperature is regulated by a pressing mechanism (not shown). A block (not shown) is brought into contact with the molding dies 1 and 2, and the heaters 7a,
By 8a, the temperature of the molding dies 1 and 2 is raised above the glass transition point of the resin to generate the resin internal pressure.

Next, the molding dies 1 and 2 are cooled by cooling water circulating in the cooling pipes 7 b and 8 b of the temperature control plates 7 and 8 and the heat radiating block 6, whereby the resin base material 2 is cooled.
1 is cooled below the heat distortion temperature. At this time, since the temperature in the vicinity of the cavity is higher than that on the heat radiation block 6 side, the heat radiation from the resin base material 21 is conducted by the heat transfer means (heat pipe) 14.
a and 14b continue to be transmitted to the heat radiation block 6.
That is, the amount of heat radiated from both ends of the resin base material 21 having a large volume in the cavity 5 due to the large-diameter heat pipe 14a is reduced by the heat pipe 14b having the small diameter. The heat radiation from the resin base material 21 in the cavity is conducted so as to be larger than the heat radiation amount from the thin central part having a small volume. on the other hand,
In the heat radiation block 6, the temperature sensor 15 near the cavity is used.
And the temperature control device 6 based on the detection information of the pressure sensor 16.
e to control the temperature and flow rate of the cooling water,
Adjust the amount of heat radiation from 1. In this way, according to the volume of the resin base material 21 in the cavity, each part is uniformly and quickly cooled. Since the optimum heat emissivity of the paint surface 17b of the heat radiation block 6 is set according to the volume of the resin base material 21 in the cavity 5, not only inside the heat radiation block 6 but also on the surface of the heat radiation block 6. Therefore, efficient cooling is performed. Therefore, even if the thickness distribution is an unbalanced plastic molded product, and the volume of the resin base material 21 in the cavity 5 is large at both ends of the cavity 5 and small at the center, the cooling rate in each part is uniform. The molding cycle is shortened by the efficient cooling process.

Next, the mirror surface is transferred to the resin base material 21,
After cooling and solidification of the resin base material 21, the mold clamping mechanism 13
The mold is opened to take out the molded product from the cavity 5. According to the present embodiment, when the volume of the resin base material 21 in the cavity 5 is unevenly distributed and both ends of the cavity 5 have a larger volume than the central portion, the vicinity of both ends of the cavity 5 is outside the molding die 2. A large-diameter heat pipe 14a is provided, and a small-diameter heat pipe 14b is provided from near the center of the cavity 5 to the outside of the molding die 2.
a heat radiation block 6 through the heat transfer means 14 including
Since the heat radiation from the resin base material 21 conducted into the inside is diverged by controlling the temperature and flow rate of the cooling water in the heat radiation block 6 based on the detection information of the temperature sensor 15 and the pressure sensor 16, By promoting heat radiation at both ends and suppressing heat radiation at the center, efficient cooling can be achieved by making the cooling speed of each part uniform. Further, by using cooling water as the cooling medium, the cooling rate can be increased when a large heat radiation amount adjustment is required. Therefore, it is possible to suppress the deterioration of the shape accuracy and the occurrence of optical distortion, to obtain a high-precision plastic molded product, and to shorten the molding cycle. Further, also with the paint surface 17b, efficient cooling from the surface of the heat radiating block 6 can be easily performed with a preset optimal heat emissivity, and uniform shrinkage of each part can be achieved.

As described above, according to the present embodiment, the amount of heat radiation by the heat radiation block 6 is adjusted based on the detection information of the temperature sensor 15 and the pressure sensor 16 provided in the vicinity of the cavity. According to the volume, control is performed so as to accelerate the thick part with a large volume and suppress the thin part with a small volume, so that uniform cooling of the entire molded product can be efficiently realized.

In this embodiment, the heat radiation block 6 is arranged between the movable mold 2 and the temperature control plate 8, but depending on the arrangement of the cavities 5 in the molds 1 and 2,
It may be configured to be mounted between the molding die 1 and the temperature control plate 7 or on another die surface. By doing so, it is possible to flexibly cope with an unbalanced molded product having a complicated shape and a thickness distribution, and uniform cooling can be realized as a whole.

[0036]

As described above, according to the present invention,
Heat transfer means (including first and second heat transfer means) penetrating the mold from the input part of the molding die forming the cavity is provided, and heat is radiated from the resin in the cavity to form the cavity. It diverges to the outside of the mold according to the distance from the entrance of the molding die to the surface of the mold and the volume of the resin in the cavity, so that the thickness distribution is unbalanced, the shape is complicated, and the cavity is formed. Even when the distance from the entering piece to the surface of the mold is long, uniform cooling can be efficiently realized and the molding cycle can be shortened. More specifically, the temperature and pressure of the resin in the cavity are detected by a temperature sensor and a pressure sensor near the cavity, and the heat transfer means radiates heat from the resin in the cavity to the outside of the mold from the input piece. When conducting heat, the amount of heat radiation is adjusted based on the detection information of each sensor by the heat radiation adjustment means (= heat radiation block), so uniform cooling is efficiently performed to suppress molding distortion, and high precision plastic molded products can be produced. Obtainable.

Further, since a heat pipe having excellent thermal conductivity is used as the heat transfer means, heat radiation from the resin in the cavity can be efficiently conducted from the vicinity of the cavity to the inside of the heat radiation block. Further, by changing the diameter of the heat pipe, the amount of heat conducted from the resin in the cavity to the heat radiating block depends on the distance from the input piece of the molding die forming the cavity to the surface of the mold and the amount of heat in the cavity. Since it is configured differently according to the volume of the resin, it can flexibly cope with a plastic molded product having an unbalanced thickness distribution and a complicated shape, and can efficiently realize uniform cooling.

Further, since a gas or liquid cooling medium is passed through the heat radiating block and controlled based on the detection information of the temperature sensor and the pressure sensor, it is possible to cope with fine temperature adjustment or large temperature adjustment, and to improve efficiency. It is possible to adjust the amount of heat radiation. In addition, since the heat radiation block surface has a thermal emissivity adjusting means including a synthetic resin film surface, a paint surface, and a finished surface, the thermal emissivity according to the volume of the resin in the cavity is set. Thus, heat radiation from the resin in the cavity can be more efficiently dissipated.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a plastic molding die showing a first embodiment of the present invention.

FIG. 2 is a diagram showing an I part including a heat radiation block 6 of FIG.

FIG. 3 is a view showing the inside of a heat radiation block 6 of FIG. 2;

FIG. 4 is a diagram showing a change in a cooling rate due to sticking of a black film.

FIG. 5 is a diagram showing the thermal emissivity for each color of a synthetic resin film.

FIG. 6 is a cross-sectional view of a plastic molding die according to a second embodiment of the present invention.

FIG. 7 is a view showing an I section including the heat radiation block 6 of FIG. 7;

FIG. 8 is a diagram showing thermal emissivity for each color of paint.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 fixed mold 2 movable mold 3 fixed input piece 4 movable input piece 5 cavity 6 heat dissipation block 14, 14a, 14b heat pipe 15 temperature sensor 16 pressure sensor 17 thermal emissivity adjusting means 17a synthetic resin film 17b paint surface 19 resin 21 Resin base material

Claims (9)

[Claims] 1. A molding die for a plastic molded product which is integrally joined to inject and fill a molten resin, and then forms a cavity for solidification by cooling. A molding die for a plastic molded product, comprising: a heat transfer means for conducting and radiating from an insertion piece of the molding die to the outside of the die. 2. A resin base material having a substantially final shape is inserted into the cavity to form a cavity. The mold is then clamped, and the resin base material is heated to generate a resin internal pressure. Then, in a molding die of a plastic molded product which is cooled and solidified, heat is radiated from a portion where the volume of the resin in the cavity is large, and is conducted from an input piece of the molding die forming the cavity to outside of the die. The first heat transfer means that radiates and radiates heat from a portion where the volume of the resin in the cavity is small from the portion of the molding die forming the cavity to the outside of the die. A molding die for a plastic molded product, comprising a second heat transfer means. 3. A molding die for a plastic molded article which is integrally joined to inject and fill a molten resin, and then forms a cavity for solidification by cooling. The molding die is provided in the vicinity of the cavity. Detecting means for detecting temperature and pressure, and provided from the entrance of the molding die forming the cavity to the outside of the die, penetrating the molding die, and radiating heat from the resin in the cavity. A heat transfer means for conducting to the outside of the mold; and a heat transfer means connected to the heat transfer means and provided in contact with the surface of the mold, and adjusts a heat release amount from the resin in the cavity based on detection information of the detection means. A molding die for a plastic molded product, comprising: a heat radiation adjusting means. 4. A resin base material having a substantially final shape is inserted into the cavity so as to be integrally joined to form a cavity, and after clamping the mold, the resin base material is heated to generate a resin internal pressure. A molding die of a plastic molded product which is cooled and solidified thereafter, provided in the vicinity of the cavity, detecting means for detecting the temperature and pressure of the resin in the cavity, and a molding die for forming the cavity. From the input piece to the outside of the mold, provided through the molding die,
First heat transfer means for conducting heat radiation from a portion of the cavity having a large volume of resin to the outside of the mold and radiating the heat; and conducting heat radiation from a portion of the cavity having a small volume of resin to the outside of the mold. And a heat transfer means comprising a second heat transfer means which diverges, and is provided in contact with the heat transfer means and in contact with the surface of the mold, and from the resin in the cavity based on detection information of the detection means. And a heat radiation adjusting means for adjusting a heat radiation amount of the plastic molded article. 5. The heat transfer means has a heat pipe.
5. The plastic molding die according to claim 3, wherein one end of the heat pipe is located near the cavity, and the other end is inserted into the heat radiation adjusting means. 6. The heat pipe according to claim 1, wherein a diameter of the heat pipe is different depending on a distance from an insertion portion of the molding die forming the cavity to a surface of the molding die and a volume of the resin in the cavity. The plastic molding die according to claim 5, wherein: 7. The heat radiation adjusting means has a space through which a gas as a cooling medium circulates, and a plurality of ventilation holes formed in a surface portion covering the space, and controls a gas flow rate and the gas flow. 7. The molding die for a plastic molded product according to claim 3, wherein the amount of heat radiation from the resin is adjusted by selectively sealing pores. 8. The heat radiation adjusting means has a circulation path for circulating a liquid as a cooling medium, and adjusts a heat radiation amount from the resin according to a temperature and a flow rate of the liquid. A molding die for a plastic molded product according to any one of claims 3 to 6, characterized in that: 9. A plastic molded product according to claim 3, wherein said heat radiation adjusting means has a thermal emissivity adjusting means including a synthetic resin film surface, a paint surface and a processed surface on a surface portion thereof. Molding mold.