JPH0542543A - Breathable mold and formation of cooling water passage in the mold - Google Patents

Abstract

PURPOSE:To provide a breathable mold which can be cooled directly with cooling water. CONSTITUTION:In the processing of water cooling in a breathable mold, vents 14, 26, 28 for a cooling water passage 30 are bored, and a plating layer 18 is formed on the inner surfaces of the vents 14, 26, 28 so that the permeation of cooling water into the mold 12 from the inner surfaces of the vents 14, 26, 28 can be prevented.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a breathable mold that can be cooled by cooling water and a method for forming a cooling water flow passage in the breathable mold.

[0002]

2. Description of the Related Art Conventionally, a so-called breathable mold has been used as a kind of mold for injection molding of a resin in order to facilitate air bleeding from a molding cavity when a molding material is filled. .. Such a breathable mold is formed with a porous structure, for example, by providing minute through holes, or by a sintered metal or the like.

Generally, in a mold for injection molding or the like, in order to improve a molding cycle, a cooling water flow passage is provided in the mold to cool the mold after filling the molding cavity with the molding material. However, in the breathable mold as described above, even if the cooling water flow passage is bored, the cooling water penetrates into the molding cavity side through the mold. However, defects such as abnormalities in the molded product are caused.

Therefore, in the air-permeable mold, a method of inserting a pipe into the bored hole to form a cooling water flow passage, or a method of inserting a rod made of a material having good heat conductivity into the air-permeable mold. By cooling the base of the rod with cooling water,
An indirect water cooling method has been adopted.

However, in any of these methods, if there is a gap between the pipe or rod and the air-permeable mold, the cooling effect is significantly reduced by the air layer interposed there, so that high machining is required. There is a problem that precision is required and die manufacturing is difficult.

Further, in such a method, it was difficult to arrange the pipes and rods three-dimensionally, and therefore, a sufficient cooling effect could not be obtained yet.

[0007]

The present invention has been made in view of the above circumstances, and the problem to be solved is to provide an air-permeable mold that can be directly cooled by cooling water. And to provide a method of forming a cooling water flow passage in an air-permeable mold capable of being directly cooled by cooling water.

In order to solve such a problem, according to the present invention, a mold having air permeability is formed, and a through hole for a cooling water flow passage is formed inside the mold. The gas permeable mold is characterized in that the inner surface of the through hole is plated.

Further, according to the present invention, (a) a step of forming a through hole for circulating cooling water in a gas-permeable mold, and (b) a through hole in the gas-permeable mold. A step of forming a plating layer on the inner surface, (c) a step of forming a through hole for circulating cooling water in a mold base assembled to the breathable mold, and (d) a mold base,
A method of forming a cooling water flow passage in a gas permeable mold, which comprises assembling the gas permeable mold so that the through holes for circulating the cooling water are communicated with each other, is also a feature thereof.

[0010]

The embodiments of the present invention will now be described in detail with reference to the drawings in order to clarify the present invention more specifically. In this embodiment, the structure of the breathable mold having the structure according to the present invention will be described according to its manufacturing process.

First, as shown in FIG. 1, a breathable mold 12 having a recess 10 forming a predetermined molding cavity is prepared. The mold 12 is called a receiving piece, and cooperates with a mold base described later to form a fixed-side molding die or a movable-side molding die. Further, the mold 12 has a porous chamber structure having air permeability, which is provided with a large number of continuous holes having a minute diameter, which are open to the inner surface of the recess 10 inside thereof. It is formed of a sintered metal obtained by sintering etc.

In the die 12, a proper number of through holes 14 for circulating cooling water are bored by a drilling machine or the like around the portion where cooling is required, for example, around the recess 10. .. The through-hole 14 is formed in a two-dimensional shape or a three-dimensional shape as needed. For example, as shown in the drawing, both ends of the through-hole are sealed with sealing materials 16 and 16. By sealing, the bent through hole 14 is formed. Further, both ends of the through hole 14 are the outer peripheral surface of the mold 12, and on the joint surface with a mold base described later, in the present embodiment, the back surface of the mold 12 (opening side of the recess 10). The surface on the opposite side) is opened.

Next, by plating the inner surface of the through hole 14 formed in the die 12, the inner surface of the through hole 14 is covered with the plating layer 18 as shown in FIG. Excuse me. The formation of the plating layer 18 is
Although it is performed according to a conventionally known plating method, since it is necessary to form a plating layer on the inner surface of the hole, the hot dipping method or the electroplating method is preferably used depending on the material of the plating layer and the like. Can be adopted.

Simultaneously with the formation of the plating layer 18 on the inner surface of the through hole 14, the connection portion plating layer 20 is formed in the opening of the through hole 14 in an annular shape having a predetermined width.

For example, when the plating layers 18 and 20 are formed by solder plating by the hot dipping method, first, the through hole 14 is formed, and the mold 12 that has been subjected to a pretreatment such as degreasing is first prepared. After heating to about 150 ℃, plating layer 1
Flux is applied to the places where 8 and 20 are to be formed. Then, the mold 12 is dipped in a molten solder bath to sufficiently wet the solder, and then the mold 12 is pulled up, so that a desired plated layer 18, 2 is applied to a portion where the flux is applied.
0 can be formed respectively. According to the hot dipping method as described above, it is possible to form a relatively thick plating layer having a thickness of about 100 μm or more.

Alternatively, the plating layers 18 and 20 are
In the case of forming by chrome plating by electroplating, first, through holes 14 are formed, and in a mold 12 that has been subjected to pretreatment such as degreasing, a portion where a plating layer need not be formed, Masking is done using paint, tape, sheets, etc. Next, the mold 12 is immersed in a molten chromium bath, electroplating is performed using the mold 12 as a cathode, and then the mold 12 is pulled up to form target plating layers 18 and 20 on the unmasked portions. can do. The chrome plated layer formed by the electroplating method as described above is usually formed with a layer thickness of about 20 μm.

That is, by such plating treatment,
The inner surface of the through hole 14 provided in the die 12 is the plating layer 18
And the minute air vents opening there are covered. Thereby, the through hole 14
However, as a conduit that prevents the penetration of fluid into the wall surface,
It is formed.

On the other hand, in a step different from the above-described manufacturing of the mold 12, a mold base 22 to which the mold 12 is assembled as shown in FIG. 3 is prepared. The mold base 22 is also called a mother die, is made of a material (for example, steel) having a higher strength than the die 12, and is provided with a die accommodating recess 24. The mold 12 is housed therein and fixed by bolts or the like to form a fixed-side mold or a movable-side mold. In the figure, 29 is an annular groove for disposing a seal member 32 described later.

The mold base 22 is provided with a through hole 26 for supplying cooling water and a through hole 2 for discharging cooling water.
8 and 8 are perforated so as to be opened in the mold accommodating recess 24, respectively. The opening positions of the through holes 26 and 28 in the mold accommodating recess 24 are determined according to the opening positions of the through holes 14 formed in the mold 12.

Thereafter, as shown in FIG. 4, the mold 12 is inserted into the mold accommodating recess 24 of the mold base 22 and fixed by bolts or the like to be integrally assembled. That is, by this assembly, both side openings of the through hole 14 provided in the mold 12 are connected to the through holes 26 and 28 provided in the mold base 22, respectively. Thereby, those through holes 1
4, 26 and 28 cooperate to form the cooling water flow passage 30.

When the mold 12 is assembled to the mold base 22 as described above, a sealing member 3 such as an O-ring is used.
2 are arranged in annular grooves 29 provided around the openings of the through holes 26 and 28 in the mold base 22, respectively. Then, the sealing member 32 is pressed between the connection portion plating layer 20 of the mold 12 and the mold base 22, so that the connection portion between the through hole 14 and the through holes 26, 28 is fluid-tightly connected. Will be punished.

Therefore, in the molding die manufactured in this manner, the cooling water supply through hole 26 and the cooling water discharge through hole 2 of the mold base 22 are attached to the molding apparatus.
By connecting cooling water circulation pipes to 8 and circulating cooling water respectively, the cooling water is caused to flow through the through holes 14 formed inside the die 12,
Thus, the mold 12 is water-cooled.

Further, in the through hole 14 formed inside the mold 12, the inner surface of the through hole 14 is covered with the plating layer 18, and water penetrates into the mold 12 from the inner surface. Therefore, problems such as defective molding due to the permeation of the cooling water flowing through the through holes 14 into the molding cavity are not caused.

Moreover, since the through hole 14 of the die 12 is formed by directly punching the die 12,
The thermal conductivity between the cooling water circulated in the through hole 14 and the die 12 is extremely good, and excellent cooling efficiency can be stably exhibited.

Further, the through hole 14 of the mold 12 can be formed two-dimensionally or three-dimensionally, and the cooling water passage can be efficiently arranged around the molding cavity. Therefore, even more excellent cooling efficiency can be obtained.

Further, in the molding die having the above-described structure, it is not necessary to insert and arrange another member such as a pipe or a rod into the mold 12, and therefore, compared with the cooling structure of the conventional breathable mold. Then, it has the advantage that the structure is extremely simple and the manufacturing is easy.

Furthermore, in this embodiment, the through hole 14
Plating layer 20 and mold base 2 formed in the opening of
By the seal member 32 interposed between the through hole 1 and
Since the fluid tightness at the connection between the No. 4 and the through holes 26 and 28 can be ensured to a high degree, problems such as defective molding due to seepage of cooling water from the connection of the through holes can be achieved. The occurrence of can be prevented almost completely.

The embodiments of the present invention have been described in detail above, but these are literal examples and the present invention should not be construed as being limited to such specific examples.

For example, the number and shape of the through holes for the cooling water flow passages formed in the air-permeable mold are not limited to those in the above embodiment, and the shape and size of the molding cavity, Alternatively, it should be appropriately determined in consideration of the molding material and the like.

The material and thickness of the plating layer formed on the inner surface of the through hole for the cooling water flow passage is not limited to the specific description in the above embodiment. ..

Furthermore, in the above-described embodiment, the mold 12 is made of a sintered metal to give air permeability to the whole, but a part of the mold is made of a sintered metal. It is also possible to partially impart air permeability by doing so, or by providing a die with a vent having a small diameter. The present invention is also advantageously applied to such a die. Can be done.

Further, in the above-described embodiment, the seal member 32 is provided at the connecting portion between the through hole 14 of the mold 12 and the through holes 26 and 28 of the mold base 22 to secure the liquid tightness of the cooling water flow passage. However, the seal structure at such a connection site is not limited to the example. For example, using adhesive to join the connection sites,
Alternatively, as shown in FIG. 5, a connection tube 34 may be used to connect the through hole 14 and the through hole 28 (26).

Although not listed one by one, the present invention is
Based on the knowledge of those skilled in the art, it can be implemented in various modified, modified, and improved modes, and
It goes without saying that all such embodiments are included in the scope of the present invention without departing from the spirit of the present invention.

[0034]

As is apparent from the above description, in the air-permeable mold having the structure according to the present invention, the cooling water flow passage is formed by the through hole formed directly inside the mold. Therefore, it is possible to cool the breathable mold with water with a simple structure, and because the thermal conductivity between the cooling water and the mold can be obtained advantageously and stably, excellent cooling efficiency is exhibited. To get.

Further, according to the method of the present invention, the cooling water flow passage in the breathable mold is provided in the through hole formed in the breathable mold and the mold base to which the breathable mold is assembled. By means of the through holes, it can be advantageously formed in the mold in cooperation.

[Brief description of drawings]

FIG. 1 is a process chart for explaining an embodiment of the method of the present invention, which is an explanatory view showing a breathable mold having through holes.

FIG. 2 is a process drawing for explaining the embodiment of the method of the present invention, and is an explanatory view showing a breathable mold that has been subjected to a plating treatment.

FIG. 3 is a process drawing for explaining the embodiment of the method of the present invention, which is an explanatory view showing a mold base having through holes formed therein.

FIG. 4 is a process chart for explaining the embodiment of the method of the present invention, and is an explanatory view showing a molding die obtained by assembling a breathable mold to a mold base.

FIG. 5 is a cross-sectional explanatory view showing a specific example of another connection structure of the through hole formed in the breathable mold and the through hole formed in the mold base.

[Explanation of symbols]

 12 mold 14 through hole 18 plating layer 22 mold base 26, 28 through hole 30 cooling water flow passage

Claims (2)

[Claims] 1. A mold having air permeability, wherein a through hole for a cooling water flow passage is formed inside the mold, and
A breathable mold characterized in that an inner surface of the through hole is plated. 2. A step of forming a through hole for circulating cooling water in a mold having air permeability, a step of forming a plating layer on an inner surface of the hole in the gas permeable mold, A step of forming a through hole for circulating cooling water in a mold base assembled to the mold; and a step of connecting the above-mentioned breathable mold to the through hole for circulating cooling water in the mold base. And a step of assembling so that the cooling water flow passage in the breathable mold is formed.