JP2006198816A - Mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold having a simple structure, uniform in temperature distribution and capable of being rapidly regulated to a set mold temperature. <P>SOLUTION: In the mold 1 equipped with a mold temperature regulating mechanism for regulating a mold temperature by heat transfer using a heating or cooling medium, a heat transfer part 4 having a plurality of heat insulating parts comprising gaps are provided to at least a part of a mold region to which heat is transferred in the direction becoming almost right-angled to a heat transfer direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a mold for molding plastics and the like, and more particularly, to a mold that has a simple structure, a uniform temperature distribution, and can be quickly adjusted to a set mold temperature.

Conventionally, as a method of adjusting the mold temperature, the mold temperature is controlled by forcibly circulating a heat medium adjusted to a predetermined temperature by a temperature controller in a heat medium passage provided in each of the fixed mold and the movable mold. There are those that adjust, and as shown in JP-A-05-169453, water is injected into each space of the fixed mold and the movable mold, and the temperature is controlled using the heat capacity and phase transformation of the water. (For example, refer to Patent Document 1).
According to Patent Document 1, the temperature inside the mold can be directly set to the mold set temperature, and the temperature distribution of the mold is also uniform.

However, the above conventional technique has the following problems.
(1) The mold temperature is adjusted by forcibly circulating a heat medium adjusted to a predetermined temperature by a temperature controller and conducting heat. Therefore, the temperature of the heat medium at the inlet and outlet of the heat medium passage of the mold is controlled. Temperature difference occurs. As a result, the temperature distribution of the mold becomes non-uniform and local shrinkage or the like occurs in the molded product, which tends to cause molding defects.
(2) Since a temperature controller having a large-capacity pump is required to forcibly circulate the heat medium, the apparatus becomes large and expensive.
(3) When using heat capacity and phase transformation of water, the boiling point of water is limited to 100 ° C, and when molding at higher temperatures is required, oil must be used at high temperatures and is dangerous. . In addition, since the heat capacity varies depending on the shape of the mold, the molding time becomes longer to achieve a uniform temperature.

JP-A-5-169453

  The present invention has been made in view of the above-described problems of the prior art, and has a simple structure, a uniform temperature distribution, and can be quickly adjusted to a set mold temperature. The purpose is to provide a mold.

  In order to achieve the above object, the present inventors have made extensive studies. As a result, surprisingly, by providing a plurality of gaps that are heat insulation parts in the middle part of the heat transfer mechanism, the temperature distribution is uniform with a simple structure, and the temperature adjustment to the set mold temperature can be performed quickly. The inventors have found that a mold that can be performed is obtained, and have completed the present invention based on this finding.

Conventionally, in a mold provided with a mold temperature control mechanism by heat transfer, it has been considered that it is disadvantageous in considering heat transfer to provide a gap as a heat insulating part in the middle part of the heat transfer mechanism. As a result of intensive studies, they found that the heat transfer rate was improved by controlling the diffusion of heat conduction by providing a heat transfer part with a heat insulation part in the middle part of the mold. Based on this finding, the present invention has been completed.
However, it is necessary to provide a heat transfer part having a plurality of heat insulation parts composed of voids, and diffusion of heat conduction is performed via a layer composed of a plurality of heat insulation parts composed of voids and the heat transfer part. And the heat transfer rate in one direction is improved. Therefore, even if a simple large space (vacant space) is provided in the mold, the object cannot be achieved.

That is, the present invention according to claim 1 is a mold having a mold temperature adjusting mechanism for adjusting a mold temperature by heat transfer using a heating or cooling medium, and at least one of mold parts to be transferred. The present invention provides a mold characterized in that a heat transfer portion having a plurality of heat insulating portions made of voids is provided in a direction substantially perpendicular to the heat transfer direction.
The present invention according to claim 2 provides the mold according to claim 1, wherein the void ratio in the heat transfer section is 30% or more and 97% or less by volume.

According to the present invention, it is possible to obtain a mold having a uniform temperature distribution and capable of quickly adjusting the temperature to the set mold temperature.
Further, according to the present invention, a mold having a simple structure and a uniform temperature distribution can be obtained without making the apparatus large or expensive.
Furthermore, according to the present invention, when the mold temperature is increased by heat transfer using a heating medium, or when the mold temperature is decreased by heat transfer using a heating medium, an appropriate shape is selected according to the mold shape. By providing a plurality of heat insulating portions made of voids at locations where heat transfer is slow and changing the heat transfer rate, temperature unevenness due to different shapes of the mold portions is eliminated, and the mold temperature is reduced. Unevenness is eliminated and uniform mold temperature can be realized. Thereby, the temperature of each part of the obtained molded product becomes uniform, and a highly accurate molded product can be created.
That is, for example, in the case of a mold having a mold temperature adjustment mechanism that adjusts the mold temperature by heat transfer using a heating medium, a plurality of heat supplied from the heat medium is transferred to a portion where heat transfer is conventionally delayed. By providing the gap, the temperature can be raised quickly, and the entire mold can be heated uniformly and quickly. The opposite is true when a cooling medium is used.
Further, since the temperature of the mold can be raised uniformly, the temperature unevenness of each part of the molded product is eliminated, the shrinkage becomes uniform, and a highly accurate molded product can be created.

Embodiments of the present invention will be described below.
The present invention according to claim 1 relates to a mold, and in a mold having a mold temperature adjusting mechanism for adjusting a mold temperature by heat transfer using a heating or cooling medium, A heat transfer part having a plurality of heat insulating parts made of voids is provided at least in a direction substantially perpendicular to the heat transfer direction.
The heat medium will be described as an example. In the present invention, the heat transfer rate is increased by providing a mechanism for preventing heat diffusion due to heat transfer when adjusting the mold temperature by exchanging heat between the mold and the heat medium. The temperature of the mold is increased quickly and the temperature of the mold is increased by providing a mechanism to prevent such heat diffusion at a place where the temperature distribution is different (for example, a place where heat transfer is slow). Is uniform.

Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing an embodiment of the mold 1 of the present invention according to claim 1 and is a mold for manufacturing a cup case, but is not limited thereto.
In the figure, reference numeral 1A is an upper mold (movable mold), and reference numeral 1B is a lower mold (fixed mold).
A heating or cooling medium flow path 2 is formed inside the upper mold 1A, and the mold temperature is set by heat transfer using the heating or cooling medium supplied into the flow path 2. It is designed to adjust.
Similarly, a flow path 3 for a heating or cooling medium is formed inside the lower mold 1B, and heat transfer is performed using the heating or cooling medium supplied in the flow path 3. By adjusting the mold temperature.
In addition, the shape, structure, etc. of the flow path 3 are not limited to what was shown in drawing.

  The present invention according to claim 1 is directed to a mold 1 (1A and 1B) having a mold temperature adjusting mechanism for adjusting a mold temperature by heat transfer using such a heating or cooling medium. The heat transfer part 4 having a plurality of heat insulating parts made of voids is provided in at least a part of the mold part in a direction substantially perpendicular to the heat transfer direction.

Here, the heat transfer direction indicates the vertical direction in FIG.
That is, in the case of using the upper mold 1A, when a heating medium is used, the upper direction in FIG. 1, that is, the direction from the medium flow path 2 in the upper mold 1A to the lower end of the upper mold 1A (downward direction). ) Is the direction of heat transfer. Further, when a cooling medium is used, the heat transfer is reversed, so the direction (upward direction) from the lower end of the upper mold 1A toward the medium flow path 2 is the heat transfer direction.
On the other hand, in the lower mold 1B, when a heating medium is used, the direction (upward direction) from the medium flow path 3 in the lower mold 1B toward the upper end of the lower mold 1B is the heat transfer direction. is there. Further, when a cooling medium is used, the heat transfer is reversed, so the direction (downward) from the upper end of the lower mold 1B toward the medium flow path 3 is the heat transfer direction.

At least a part of the mold part to which heat is transferred has a heat transfer part 4 having a plurality of heat insulating parts made of gaps in a direction substantially perpendicular to the heat transfer direction, that is, in the left-right direction in FIG. Is provided.
2 is a cross-sectional view taken along line AA ′ of FIG. 3 is a cross-sectional view taken along line BB ′ of FIG.
The heat transfer part 4 having a plurality of heat insulating parts composed of voids may have a structure in which the gaps and the heat transfer parts are alternately arranged when viewed in cross section. Good. In short, it is only necessary to have a structure in which the air gap and the heat transfer portion are mixed so as to accelerate heat conduction.

The heat transfer part 4 having a plurality of heat insulating parts made of voids may be formed by sandwiching and joining a spherical object between two mold materials, for example, as shown in FIG. Alternatively, it may be formed by sandwiching and joining a trapezoidal object instead of a spherical object. In short, the shape of what is sandwiched between two mold materials is not limited as long as the heat transfer part 4 having a plurality of heat insulating parts made of voids can be formed.
As shown in FIG. 5, the heat transfer section 4 having a plurality of heat insulating sections composed of voids is formed by sandwiching and bonding a punching metal (punched metal net) between two mold materials. It may be. The shape of the hole opened in the punching metal (punched metal net) is not particularly limited, and various types such as a round hole and a square hole can be used.
2 and FIG. 3 are formed by sandwiching and bonding a punching metal (punched metal net) between two mold materials. When punching metal (punch metal mesh) is sandwiched and joined in this way, a dent corresponding to the size of the punching metal (punch metal mesh) is added to the mold material at the location where the punch metal (punch metal mesh) is sandwiched and joined. Is provided.
From the viewpoint of production, it is preferable to use such a punching metal (punched metal net). However, from the viewpoint of making the mold temperature uniform, spherical or trapezoidal objects made of the same material as the mold material are used. Those formed by sandwiching and bonding between two mold materials are preferable.
The joining can be performed by a known joining means including pulse current joining and diffusion joining. In addition, what is necessary is just to perform the joining process by pulse energization, etc. by a conventional method.

The ratio of the voids in the heat transfer section thus provided is not particularly limited, but as described in claim 2, it is preferably 30% or more and 97% or less by volume.
Here, when the ratio of voids in the heat transfer section is less than 30%, a heat transfer acceleration effect (or a heat transfer deceleration effect when a cooling medium is used) is sufficiently obtained when a heating medium is used. Since it is not possible, it is not preferable.
On the other hand, when the ratio of the voids in the heat transfer part exceeds 97%, the heat insulation effect becomes too large, which is not preferable.

  In addition, the size of the spherical object is not particularly limited when the heat transfer part 4 having a plurality of heat insulating parts composed of voids is formed by sandwiching and bonding the spherical object between the two mold materials, The diameter is about 0.5 to 1.5 mm. In addition, when the heat transfer section 4 having a plurality of heat insulating sections formed of voids is formed by sandwiching and bonding a punching metal (punched metal mesh), the hole diameter is not particularly limited. It is about 2 to 1.5 mm.

  What is necessary is just to use what is used normally about the mold temperature adjustment mechanism which adjusts mold temperature by heat transfer using the medium for heating or cooling.

  According to the present invention as described above, for example, when the mold temperature is increased by heat transfer using a heat medium, the temperature caused by the difference in the shape of the mold part by changing the heat transfer speed according to the mold shape. Unevenness is eliminated, non-uniformity of the mold temperature is eliminated, and a uniform mold temperature can be realized. Thereby, the temperature of each part of the molded product becomes uniform, and a highly accurate molded product can be created.

  EXAMPLES Hereinafter, although an Example etc. demonstrate this invention, this invention is not limited by these.

Test example 1
A ball of 1.0 mm diameter made of the same material is spread between two cylinders (diameter 20 mm) of SUS420J2, and pulsed under the conditions of a joining temperature of 1030 ° C. (± 5 ° C.), a joining current density of 540 A / cm ² , and a pressure of 10 MPa. Conductive joining was performed to obtain a sample (1) as shown in FIG.
About the obtained sample (1), the heating test which heats the lower part was done, and temperature was measured every 3 minutes. In particular, in consideration of the molding time, it is preferable that the temperature rises quickly in an early time, for example, between 3 minutes and 6 minutes.
The heat transfer direction is a direction from the lower part to the upper part in FIG. In addition, the shielding board was provided so that the influence of the surrounding wind might be excluded. The temperature was measured by opening a hole with a depth of 10 mm and a diameter of 1.8 mm at a position 5 mm upward from the center of the sample (1) and measuring with a thermocouple.
The result is shown in FIG. 6 together with the result of the base material that does not sandwich the ball. In FIG. 6, the result of the obtained sample (1) is displayed as “ball”, and the result of the base material that does not sandwich the ball is displayed as “base material”.

According to FIG. 6, from the comparison of the temperature rise graph of the sample (1) pulse-welded with the ball in between and the base material, the temperature rise is clearly faster in the sample (1) with the ball in between. . That is, it can be seen that the speed of heat transfer is increased by providing a gap so as to prevent heat diffusion in heat transfer.
The void volume formed by spreading the ball is theoretically 52%, but the ball is deformed by the pressure at the time of joining and the void volume is reduced, so heat transfer acceleration is achieved if the void volume is 30% or more. It turns out that an effect is acquired. It has also been found that when the void volume exceeds 97%, the temperature rise is the same as the heat transfer mechanism of the base material.
From this, it is considered that in order to adopt the heat transfer acceleration structure, it is necessary to set the volume ratio of the voids within 30% to 97%.

Test example 2
In Test Example 1, a sample as shown in FIG. 5 was obtained in the same manner as Test Example 1 except that the material sandwiched between the balls was changed to a SUS mesh plate (punching metal; hole diameter: 0.2 mm diameter). 2) was obtained.
About the obtained sample (2), the heating test which heats the lower part was done, and temperature was measured every 3 minutes. In addition, the shielding board was provided so that the influence of the surrounding wind might be excluded. The temperature measurement was performed by drilling holes with a depth of 10 mm and a diameter of 1.8 mm at the three measurement points shown in FIG. 5 (total of 3 positions each 5 mm from the center of each cylinder and the end face). This was done by measuring.

The results are shown in FIG. In FIG. 7, each measurement point number is shown.
As can be seen from FIG. 7, the temperature rises uniformly.

Test example 3
Sample (3) 3 obtained by sandwiching a ball in the same manner as in Test Example 1, sample (4) obtained by sandwiching a SUS mesh plate in the same manner as in Test Example 2, and a base material [Sample] (5)], a heating test for heating the lower part was performed in the same manner as in Test Example 1, and the temperature was measured every 3 minutes.
The results are shown in FIG. In FIG. 8, the result of the obtained sample (3) is displayed as “ball”, the result of the obtained sample (4) is displayed as “mesh”, and a base material [sample (5) that holds nothing] ] Was displayed as “base material”.

  According to FIG. 8, sample (3) obtained by sandwiching the balls in the same manner as in Test Example 1 and SUS in the same manner as in Test Example 2 as compared with the base material [Sample (5)] that does not sandwich anything. It can be seen that the sample (4) obtained by sandwiching the mesh plate has a rapid rise in the early time, such as between 3 and 6 minutes, which is closely related to the molding time.

Example 1
A cup case (cup outer diameter: 30 mm diameter) was molded by injecting 40% glass fiber-containing PPS resin at 320 ° C. using the mold shown in FIGS. .
This mold is composed of an upper mold 1 and a lower mold 1B, and each mold is sandwiched with a SUS mesh plate (punching metal; hole diameter: 0.2 mm diameter) by pulse energization joining. The formed heat transfer part 4 having a plurality of heat insulating parts made of voids is formed. In addition, the joining process by pulse energization was performed by a conventional method.
A heating or cooling medium flow path 2 is formed in the upper mold 1, and a heating or cooling medium flow path 3 is formed in the lower mold 1 B. Thus, the mold temperature is adjusted by heat transfer using a heating or cooling medium supplied into the flow path 3.

About the obtained cup case, the curvature of the bottom face was measured with a laser displacement meter. The shape accuracy (Pv value) was 3.51 μm. A contour map of the obtained cup bottom is shown in FIG.
For comparison, a cup case is similarly used using a conventional mold (a mold similar to that shown in FIG. 1 except that the heat transfer section 4 having a plurality of heat insulating sections formed of voids is not formed). The bottom warp was measured with a laser displacement meter. The shape accuracy (Pv value) was 6.35 μm. A contour map of the obtained cup bottom is shown in FIG.

  As a result, it was found that a product excellent in shape accuracy (Pv value) can be obtained when using the mold (the mold of the present invention) as shown in FIGS.

According to the present invention, the temperature rise of the mold can be accelerated, the entire mold can be uniformly heated quickly, and the mold can be uniformly heated, so there is no temperature unevenness in each part of the molded product, Shrinkage becomes uniform and a highly accurate molded product can be produced.
Therefore, the present invention can be applied to various molds including resin molds such as injection molding, and further to cooling a CPU of a computer.

It is sectional drawing which shows the one aspect | mode of the metal mold | die 1 of this invention which concerns on Claim 1. FIG. 2 is a cross-sectional view taken along line A-A ′ of FIG. 1. FIG. 2 is a sectional view taken along line B-B ′ of FIG. 1. 6 is an explanatory diagram of a sample (1) obtained in Test Example 1. FIG. It is explanatory drawing of the sample (2) obtained by Test Example 2. 6 is a graph showing the results of a heating test performed in Test Example 1. 6 is a graph showing the results of a heating test performed in Test Example 2. 6 is a graph showing the results of a heating test performed in Test Example 3. In Example 1, it is a contour map of the cup bottom face obtained using the metal mold | die of this invention. In Example 1, it is a contour map of the cup bottom obtained using the conventional metal mold | die.

Explanation of symbols

1 Mold 1A Upper mold (movable mold)
1B Lower mold (fixed mold)
2 Heating or cooling medium flow path (upper mold)
3 Heating or cooling medium flow path (lower mold)
4 Heat transfer part having a plurality of heat insulation parts consisting of gaps

Claims (2)

  In a mold having a mold temperature adjusting mechanism for adjusting a mold temperature by heat transfer using a heating or cooling medium, at least a part of the mold portion to be transferred is substantially perpendicular to the heat transfer direction. A mold having a heat transfer portion having a plurality of heat insulating portions made of voids in a direction. The mold according to claim 1, wherein a ratio of voids in the heat transfer section is 30% or more and 97% or less by volume.

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