JPH0631737A - Molding metal mold - Google Patents

Abstract

PURPOSE:To provide a metal mold capable of carrying out certainly quick gas extraction and burn prevention by enabling the metal mold to be simply constructed. CONSTITUTION:In a matched-metal mold 10 wherein a cavity 20 containing a material being a product is constructed by matching at least a pair of molds 11, 12 with a parting line 15, a storing recess part 13 is molded at a part extending over at least one side parting line 15 of the molds 11, 12 composing the matched-metal mold 10 and the cavity 20, and besides an auxiliary mold 14 consisting of porous material having an open pore of a three-dimensional reticulated structure is arranged by being stored in the storing-recess part 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding die including a male mold and a female mold, which is used for various molding such as injection molding, transfer molding or compression molding, and is suitable mainly for plastic molding. The present invention relates to a molding die.

[0002]

2. Description of the Related Art A mold for molding, which is composed of a male mold and a female mold according to a product, is used for injection molding or transfer molding. When injecting the plastic material into the cavity, the air inside the cavity must be allowed to be discharged. Also, depending on the material, there are some that generate water, volatile substances, etc. when cured, but if these volatile substances etc. remain, it is not possible to form a beautiful product, so these volatile substances, etc. are removed from the cavity. Must be ready for discharge.
The discharge of these air and volatile substances is called degassing.

In order to perform this degassing, in a conventional mold, a small hole that opens mainly in the parting line (dividing line of the molding mold) is formed. In addition, when the hole for degassing is not formed, the pressure between the molds may be relaxed for a certain period of time at the time of clamping the mold or injecting the material, and the gas may be discharged from the parting line. Has been done. When a hole for venting gas is formed, the material enters into this hole and so-called burrs are generated in the product, and it takes time to loosen the pressure between the molds. Therefore, the molding speed is reduced. The burrs are also generated when a part of the injection material oozes from the mating surface due to a defect in the mating surfaces of the male and female molds.

Particularly, in a mold for releasing gas by releasing pressure between the molds, as shown in FIG. 7B, after the mold clamping is completed and the material is filled in the cavity, The pressure between the molds is gradually reduced to remove gas and add the material by curing and shrinking. In (b) of FIG. 7, degassing is performed in the second speed or the third speed in the figure, but of course, during this time (3 to 25 seconds when the weight of the plastic product is 312 g). ) Is required, which occupies a large amount of time in one cycle of molding one product.

Therefore, the inventor of the present invention has variously studied how to form a mold which can surely perform degassing during molding within a short time and which does not cause extra burrs in a product. As a result of repeating the above, the present invention has been completed.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and the problems to be solved are to speed up molding and prevent burrs from occurring.
It is an object of the present invention to provide a mold which can be easily configured and can surely perform quick degassing and burr prevention.

[0007]

Means for Solving the Problems In order to solve the above problems, the means adopted by the present invention will be described with reference to the reference numerals used in the embodiments.
In the molding die 10 that forms the cavity 20 into which the material to be the product is injected by aligning the female dies 12 at the parting line 15, the die 1 that forms the molding die 10
Parting line 15 of at least one of 1 and 12
A storage recess 13 is formed in a portion that straddles the cavity 20 and the cavity 20, and an auxiliary mold 14 made of a porous body having open pores of a three-dimensional mesh structure is stored and arranged in the storage recess 13 to form a pair of molds When the cavity 20 is formed during the mold clamping of 11 and 12, the auxiliary mold 14 is configured to face a part of the cavity 20 and a part of the parting line 15 outside the cavity 20. It is the metal mold for molding 10 ″.

[0008]

The operation of the molding die 10 according to the present invention configured as described above will be described in the order of manufacturing steps of products. First, in this molding die 10, FIGS.
As shown in FIG.
2 has a storage recess 13 formed therein.
An auxiliary mold 14 made of a porous material having open pores having a three-dimensional mesh structure is housed and arranged therein. The recess 13 for storing and storing the auxiliary mold 14 has a male mold 11 and a female mold 12 regardless of whether the molding mold 10 is a flash mold, a press mold or a half press mold. It is formed in a portion that extends over both the cavity 20 formed by the above and the parting line 15 where the male mold 11 and the female mold 12 meet.

Therefore, the auxiliary mold 14 allows excess air in the cavity 20 to pass through the open pores of the male mold 11 relative to the female mold 12 until the male mold 11 moves downward to form the cavity 20, for example. Mold mold 10 from 15
It is discharged outside. That is, the open pores of the auxiliary mold 14 made of a porous material have a three-dimensional mesh structure, and the auxiliary mold 14 itself partially faces the cavity 20 and the parting line 15. From the cavity 20 sealed by the male mold 11 and the female mold 12.
Even if the above is formed, the extra air in the cavity 20 is discharged to the outside by the auxiliary mold 14. Also,
The fact that the open pores have a three-dimensional network structure means that
This means that the open pores are in communication with each other, whereby the hole exposed on the cavity 20 side is connected to the hole exposed on the parting line 15 side in the auxiliary mold 14. Is there.

When the cavity 20 corresponding to the product is completed as described above, the material is injected into the cavity 20, and the air in the cavity 20 corresponding to the volume of the injected material is In the same manner as described above, it is discharged from the parting line 15 to the outside of the molding die 10 through the open pores of the auxiliary die 14. Volatile substances and the like generated when the material is cured are also discharged from the molding die 10 through the open pores of the auxiliary mold 14. That is, degassing is performed.

At this time, since the open pores of the auxiliary mold 14 have pore diameters of about 5 to 25 μm, as will be described later in examples, the above-mentioned degassing is performed. Since the material injected into the cavity 20 does not pass through the open pores, the material is stopped by the auxiliary mold 14. In addition, the auxiliary mold 14 is housed in the housing recess 1 formed in the part extending over the parting line 15 and the cavity 20.
Since it is inside 3, the material inside the cavity 20 does not leak into the parting line 15 or the outside of the molding die 10. Therefore, no burr is generated on the surface of the finished product.

The important action of the molding die 10 of the present invention is to add a material for so-called degassing and hardening shrinkage, as shown as (2nd and 3rd speed) in FIG. This means that the time for one cycle of product manufacturing is shortened because the above can be performed in parallel. That is, in the molding die 10, it is not necessary to loosen the mold for degassing, and no waiting time for degassing is required. The time can be shortened. In particular,
If the weight of the plastic product is 312g,
5 cycles per cycle for a conventional mold without auxiliary mold 14.
Although it was 0.6 seconds, one cycle when the molding die 10 of the present invention was used was 33 seconds, which means a considerable time saving. Therefore, the time for manufacturing a product using the molding die 10 can be greatly shortened, and not only the manufacturing can be speeded up, but also the product cost can be reduced accordingly.

Further, since the auxiliary mold 14 is accommodated in the accommodating recess 13 formed in the male mold 11 or the female mold 12, it can be replaced, and in the following cases. It is very advantageous. That is, even if the auxiliary mold 14 itself is damaged, the auxiliary mold 14 itself may be replaced without repairing the male mold 11 or the female mold 12. On the other hand, various characters such as the so-called lot number required by the manufacturer for molded products are
It is necessary to put a mark, but these lot numbers, etc. must be changed from time to time due to the types of molded products or the replacement of materials. In such a case, if the auxiliary die 14 side is processed so that the lot number is attached, the auxiliary die 14
It is possible to easily change the required lot number and the like only by exchanging only one.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a molding die 10 according to the present invention will be described according to each embodiment shown in the drawings. FIG. 1 is a sectional view of a molding machine that employs the molding die 10 according to the present invention. The molding die 10 used in this molding machine is
The configuration is as schematically shown in FIGS.

The molding die 10 shown in FIG. 2 is of a type called a flash die, and a core formed on the lower surface side of the male die 11 in the drawing enters a recess of the female die 12 to have a predetermined shape. The cavity 20 is formed. Although not shown in FIG. 2, a sprue bush for injecting the material into the cavity 20 is formed in the male mold 11 or the female mold 12. Then, in this molding die 10, the upper surface of the female die 12 is a parting line 15.

An accommodating recess 13 is formed on the outer periphery of the upper part of the recess of the female mold 12 and surrounds all or part of the recess. The accommodating recess 13 includes a male mold 11 and a female mold 12. The cavity 20 formed by the auxiliary mold 1 on the female mold 12.
It spans both 4 and. An auxiliary mold 14 is housed in the housing recess 13 and a part of which faces the parting line 15 and a part of the cavity 20. The auxiliary mold 14 is attached to the housing recess 13 and It can be removed freely. In other words, the storage recess 13 has a part facing the inside of the cavity 20, and another part facing the parting line 15, and is replaceable. is there.

Auxiliary mold 1 housed in the housing recess 13
Reference numeral 4 denotes a porous body having open pores having a three-dimensional mesh structure. If the open body 4 has such open pores, the auxiliary mold 14 is formed of various materials such as sintered metal and ceramics. You can do it. The auxiliary mold 14 in this embodiment is formed by blending ceramic powder, metal powder, various fibers, etc., and pouring the mixture into a mold, followed by drying and firing, and the following physical characteristics. With.

Heat resistance Approx. 900 ° C. Porosity of open pores 15 to 40 vol.% Pore diameter of open pores 5 to 25 μm Air permeability 3 to 25 cm ³ / cm ² sec Surface roughness 6 to 10 μm RMaX

The auxiliary mold 14 may be provided in a part of the recess of the female mold 12 as described above. That is, it is not necessary to form the auxiliary mold 14 over the entire circumference of the recess of the female mold 12, and it may be a partial mold if a place or a size that allows sufficient degassing is selected. is there. In addition, this auxiliary type 14
At the time of forming, the surface exposed in the cavity 20 is preferably processed for the lot number, the manufacturer's name, etc. to be attached to a part of the molded product.

Since the auxiliary mold 14 has open pores of a three-dimensional network structure, that is, it is porous, it forms a so-called "plain surface" on the surface of the product. This "plain surface" is effective as a surface for attaching a label or the like. The reason for this is that the label attached to a perfectly flat surface will stick firmly, but the label attached to this "plain" surface will stick relatively loosely.
The peeling can be carried out without leaving a label or adhesive residue therefor.

In the molding die 10 shown in FIG. 2,
Since the parting line 15 coincides with the upper surface of the female mold 12, the storage recess 13 and the auxiliary mold 14 may have the most basic shapes. When it is in the recess, the molding die 10 shown in FIG. 3 may be used. Since the core on the male die 11 side is in sliding contact with the auxiliary mold 14 in the case shown in FIG. 3, it is preferable to form the auxiliary mold 14 with a width in the vertical direction as small as possible. Also in the half-pressing type molding die 10 shown in FIG. 4, the auxiliary die 14 and a part of the core on the male die 11 side are in sliding contact, but since the sliding contact amount is small, The shape as shown in FIG.

FIG. 5 shows a flash-type molding die 10 similar to that shown in FIG. 2, and the sectional shape of the auxiliary die 14 used in this case is shown in FIG. As shown, it is L-shaped. In this case, the area of the auxiliary mold 14 exposed to the parting line 15 and the cavity 20 can be increased while the material of the auxiliary mold 14 is reduced, and the positioning of the auxiliary mold 14 with respect to the storage recess 13 can be performed. It has the advantage that it can be made easier.

[0023]

As described above in detail, according to the molding die 10 of the present invention, the auxiliary mold 14 constitutes a part of the cavity 20, and the auxiliary mold 14 has open pores having a three-dimensional mesh structure. Since the cavity 20 and the parting line 15 side are communicated with each other, it is possible to provide a mold that can be easily configured and can surely perform quick degassing and burr prevention. is there.

Further, since the auxiliary mold 14 can be accommodated in the accommodation recess 13 formed in the male mold 11 or the female mold 12 in an exchangeable manner, the replacement is completely different from that of the male mold 11 or the female mold 12. Not only can it be performed independently, but when it is desired to attach different numbers or symbols to the products, the work can be easily performed by using the auxiliary mold 14.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a molding machine configured by adopting a molding die according to the present invention.

FIG. 2 is a cross-sectional view showing an outline of the molding die.

FIG. 3 is a cross-sectional view showing another embodiment of the molding die.

FIG. 4 is a sectional view showing still another embodiment of the molding die.

FIG. 5 is a cross-sectional view of a molding die that uses an auxiliary mold having a different cross-sectional shape.

FIG. 6 is a partially enlarged perspective view of the auxiliary mold used in FIG.

FIG. 7 is a graph showing one cycle in which a product is molded by a molding die of this type.

[Explanation of symbols]

 10 Molds for molding 11 Male mold 12 Female mold 13 Storage recess 14 Auxiliary mold 15 Parting line 20 Cavity

Claims (1)

[Claims] 1. A molding die for forming a cavity into which a material to be a product is injected by aligning at least a pair of molds on a parting line, wherein at least one of the molds for forming the molding die comprises: An accommodating recess is formed in a part that extends over the parting line and the cavity, and an auxiliary mold made of a porous body having open pores of a three-dimensional mesh structure is accommodated in the accommodating recess, and the pair of molds are arranged. When the cavity is formed during mold clamping, the auxiliary die is configured to face a part of the cavity and a part of the parting line outside the cavity. Type.