JPH06179098A - Die and method for powder compression molding - Google Patents

Abstract

PURPOSE:To improve air-vent property in powders by constituting the powder contact part of a die of a porous body having pores communicating with the inside and the outside of the mold. CONSTITUTION:A powder compression molding die 10 is constituted of a mortar 11 and upper and lower rods 12, 13. After filling powders in the mortar 11 for which the lower rod 13 is inserted and arranged in a prescribed position, the upper rod 12 is inserted into the mortar 11 for the compression molding of the powders, and a molded article is pushed up by the lower rod 13 outside the mortar 11 to be discharged. Here, the mold 10 is constituted of a metallic porous body 15 for the whole body including the powder contact part 11A of the mortar 11. At the unfilled time of powders into the die 10, a pressurized fluid is applied through a pressure chamber 17 to the outside surface of the die that is constituted of the porous body 15, and the powders filling the pores of the porous body 15 are blown away inside the die. Consequently, the positional relation to constitute the die, e.g. between the mortar and the rods is set freely.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder compression molding die and method for compression molding powder such as bath salts, medicines and foods.

[0002]

2. Description of the Related Art Conventionally, as a powder compression molding die, JP-A-62-62
-230500 has been proposed.
In this prior art, as shown in FIG. 4, a die 1 and upper and lower punches 2 and 3 are used as a molding die. After the lower punch 3 is inserted in a predetermined position, the die 1 is filled with powder. , Upper punch 2
Is inserted into the die 1 to compression-mold the powder, and the compression-molded molded product is pushed up by the lower punch 3 to the outside of the die 1 and discharged.

At this time, the above-mentioned compression molding work is a work of pushing out the air contained in the powder to the outside of the molding die, but the air venting path is in the fine gap between the die 1 and the punches 2, 3. However, in the case of high-speed molding of powder having poor air bleeding or powder having a large air content, air is not extruded sufficiently and compression molding is performed. For this reason, the powder is forcibly compression-molded while containing a large amount of air to some extent, and the repulsive force of the air remaining in the molded product after molding causes surface peeling (capping phenomenon) of the molded product.

Therefore, in the prior art shown in FIG.
Air vent hole 4 that connects the inner surface facing the lower punch 3 to the external space
To improve air removal from the powder during molding.

[0005]

However, the prior art has the following problems.

The air vent hole 4 is not opened in the powder contact portion of the die 1, but is only provided facing the lower punch 3. Therefore, the air in the powder is still only extruded through the fine gap between the die 1 and the punches 2 and 3, and it is difficult to reliably remove the air, which causes the capping phenomenon. It cannot be prevented enough. Therefore, particularly with respect to powder having poor air bleeding and powder having a large air content, the formability at high speed and high compression ratio is poor.

Since the position of the air vent hole 4 with respect to the die 1 is limited to the position facing the lower punch 3, the positional relationship between the die 1 and the lower punch 3 at the time of molding is restricted.

It is an object of the present invention to improve the air bleeding property in the powder when the powder is compression-molded, and to freely set the positional relationship between, for example, a die and a punch that compose the molding die. To do.

[0009]

According to a first aspect of the present invention, in a powder compression molding die, at least the powder-contacting portion of the die is made of a porous body having holes communicating with the inside and outside of the die. It was done like this.

According to a second aspect of the present invention, in the powder compression molding method using the powder compression molding die according to the first aspect, the outer surface of the mold made of a porous body when the powder is not filled in the mold. A pressurized fluid is applied to the nozzle to blow out the clogging powder in the pores of the porous body into the mold.

According to a third aspect of the present invention, in the powder compression molding method according to the second aspect, the suction granules are formed on the outer surface of the mold, which is a porous body, at the time of filling and molding the powder in the mold. Is applied to forcibly exhaust the air in the mold through the pores of the porous body.

[0012]

According to the present invention described in claim 1,
Has the effect of.

Since the powder contact portion of the mold is made of a porous body having holes capable of functioning as air vent holes, the air in the powder can be directly discharged from around the powder to the outside of the mold. Further, since a large number of pores are formed by the porous body, it is possible to secure a high air bleeding property according to the porosity (ratio of the total pore area to the total surface area of the powder contact portion). Therefore, it is possible to secure the compression moldability without causing the capping phenomenon at a high speed and a high compression ratio even for the powder having poor air bleeding or the powder having a large air content.

As long as the powder-contacting part of the mold is made of a porous material and the powder is brought into direct contact with the porous material, the positional relationship between, for example, the die and the pestle which form the mold is set to a specific position. It can be set freely without the need for restraint.

According to the present invention described in claim 2, the following effects are obtained. When the powder is not filled, a pressurized fluid is applied to the outer surface of the mold, which is made of a porous material, and the clogging powder in the pores of the porous material is blown out into the mold, so that the above-mentioned air bleeding property is constantly maintained. it can.

According to the present invention described in claim 3, there is the following action. At the time of filling and molding the powder, a suction fluid is applied to the outer surface of the mold made of a porous body, and the air in the mold is forcedly exhausted through the pores of the porous body, whereby the above-mentioned air bleeding property can be further improved.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic diagram showing a first embodiment, and FIG.
A schematic diagram showing an embodiment, FIG. 3 is a schematic diagram showing a third embodiment,
FIG. 4 is a schematic diagram showing a conventional example.

(First Embodiment) (FIG. 1) A powder compression molding die 10 comprises a die 11, and upper and lower punches 12, 1.
3, the lower punch 13 is inserted into the die 11 at a predetermined position, and the upper die 12 is inserted into the die 11 to compress and mold the powder. The formed product is pushed up by the lower punch 13 to the outside of the die 1 and discharged. In addition, mortar 1
1 is fixed to a mortar holder 14.

Here, in the molding die 10, the whole of the die 11 including the powder-contacting portion 11A is made of the metal porous body 15. That is, the porous body 15 forms the inner surface of the powder contact portion 11A of the die 11 and is directly or indirectly exposed to the atmosphere. The porous body 15 has holes communicating with the inside and outside of the die 11, and the diameter of the holes is smaller than the particle diameter of the powder.

Specifically, the average particle diameter of the powder is 100 to 200 μm.
When m, the average pore diameter of the porous body 15 is 1 to 10 μm,
20-30% porosity (ratio of total pore area to total surface area)
Is preferred. As the powder having the above average particle diameter,
For example, the main ingredients are sodium hydrogen carbonate, sodium carbonate,
There are bath agents that are succinic acid and fumaric acid. As the metal porous body having the above average pore diameter and porosity, there is, for example, Porcelax II (trade name of Shinto Industry Co., Ltd.).

Further, in the molding die 10, the pressure chamber housing 1 is provided around the lower outer surfaces of the die 11 and the die fixing holder 14.
6 is sealed, and a pressure chamber 17 is defined around the lower end surface of the die 11.

A pressurized air supply pipe 18 for applying pressurized air to the pressure chamber 17 and a suction air supply pipe 19 for applying suction air to the pressure chamber 17 are connected.

The pressurized air supply pipe 18 is provided with a switching valve 22 for switching and connecting a pressurized air generator 21 such as an air compressor to the pressure chamber 17, and the suction air supply pipe 19 is for generating suction air such as a vacuum pump. A switching valve 24 for switching and connecting the device 23 to the pressure chamber 17 is provided.

The molding operation by the molding die 10 will be described below. (1) The lower punch 13 is inserted and arranged at a predetermined position in the mortar 11, and the mortar 1
1 is filled with a predetermined amount of powder.

(2) The upper punch 12 is inserted into the die 11 from the standby position and the powder is compression molded. After this compression molding, the upper punch 12 is pulled back to the standby position outside the die 11.

(3) The compression-molded molded product is pushed out of the die 11 by the lower punch 13 and discharged. After discharging the molded product, the lower punch 13 is reset to a predetermined position in the die 11.

In the molding die 10, the pressurized air generated by the pressurized air generator 21 is supplied from the pressurized air supply pipe 18 to the pressure chamber 17 when the powder is not filled in the die 11. By applying this pressurized air to the outer surface of the porous body 15,
The clogging powder in the pores of the porous body 15 is blown out into the die 11.

Further, in the molding die 10, the suction air generated by the suction air generator 23 is supplied from the suction air supply pipe 19 to the pressure chamber 17 at the time of filling and molding the powder in the die 11. The suctioned air is applied to the outer surface of the porous body 15 to forcibly exhaust the air inside the die 11 through the holes of the porous body 15.

The arrows in the figure show the flow of pressurized air and suction air. The air discharged from the mortar 11 during molding is the mortar 1
Not only is it discharged from the lower end surface of 1 to the pressure chamber 17 side, but is also discharged directly from the upper end surface of the die 11 into the atmosphere.

The operation of this embodiment will be described below. Porous body 15 having holes capable of functioning as air vent holes
Since the powder contact portion 11A of the mortar 11 is constituted by, the air in the powder can be directly discharged from around the powder to the outside of the mold 10. Since a large number of pores are formed by the porous body 15, it is possible to secure a high air bleeding property according to the porosity of the die 11 (the ratio of the total pore area to the total surface area of the powder contact portion 11A). Therefore, it is possible to secure the compression moldability without causing the capping phenomenon at a high speed and a high compression ratio even for the powder having poor air bleeding or the powder having a large air content.

As long as the powder-contacting portion 11A of the die 11 is composed of the porous body 15 and the powder is brought into direct contact with the porous body 15, the die 11 and the pestle 1 constituting the mold 10
There is no need to constrain the positional relationship between 2 and 13 to a specific position,
It can be set freely.

When the powder is not filled, pressurized air is applied to the outer surface of the die 11 made of the porous body 15 to blow out the clogging powder in the pores of the porous body 15 into the die 11. The air bleeding property of can be constantly maintained.

During the filling and molding of the powder, the porous body 15
Suction air is applied to the outer surface of the mold 11 made of
By forcibly exhausting the air in the mold 10 through the holes of No. 5, the above-mentioned air venting property can be further improved.

(Second Embodiment) (FIG. 2) The powder compression molding die 30 is different from the molding die 10 of FIG. 1 in that the pressure chamber 17 and the pressurized air supply pipe 18 around the lower outer surface of the die 11 are provided. The suction air supply pipe 19 has been removed.

According to this molding die 30, since the die 11 is composed of the porous body 15, it has the function of the molding die 10. The arrows in the figure indicate the flow of exhaust air.

(Third Embodiment) (FIG. 3) The powder compression molding die 40 differs from the molding die 10 in that
Pressure chamber 17 around the outer surface of the lower end of the mortar 11, the pressurized air supply pipe 1
8. The suction air supply pipe 19 is removed, and not only the die 11 but also the punches 12 and 13 are made of the porous metal body 15.

According to this molding die 40, at the time of molding, the air vent region for discharging the air in the powder directly to the outside from around the powder is expanded so as to extend over the entire circumference of the powder. By using the porous body 15, the air bleeding property can be further improved. The arrows in the figure indicate the flow of exhaust air.

However, in practicing the present invention, it is sufficient that at least the powder contact portion of the mold is formed of a porous material. For example, in each of the above embodiments, the die 11 and the punch 1 are used.
It is not indispensable to form the whole of 2 and 13 with a porous body, and only the part of the die 11 and the punches 12 and 13 may be formed with a porous body.

Further, in the practice of the present invention, not only a part of the outer surface of the mold but also a pressurized fluid or a suction fluid may be applied to the entire outer surface of the mold.

Further, in the practice of the present invention, the forming die is not limited to the die and the upper and lower punches, and may be constituted by a concave die and a convex die.

[0041]

As described above, according to the present invention, when the powder is compression-molded, the air-releasing property in the powder is improved, and the positional relationship between, for example, the die and the pestle constituting the molding die is freely set. It can be configurable.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a first embodiment.

FIG. 2 is a schematic diagram showing a second embodiment.

FIG. 3 is a schematic diagram showing a third embodiment.

FIG. 4 is a schematic view showing a conventional example.

[Explanation of symbols]

 10 Powder Compression Mold 11 Mill 11A Powder Contacting Part 12, 13 Kisuki 15 Porous Body 18 Pressurized Air Supply Pipe 19 Suction Air Supply Pipe

Claims (3)

[Claims] 1. A powder compression molding die and method, wherein at least the powder contact portion of the die is made of a porous body having pores communicating with the inside and outside of the die. 2. A powder compression molding method using the powder compression molding die according to claim 1, wherein a pressurized fluid is applied to an outer surface of the die made of a porous body when the powder is not filled in the die, A powder compression molding method characterized in that clogging powder in the pores of a porous body is blown into a mold. 3. The powder compression molding method according to claim 2, further comprising applying suction granules to the outer surface of the mold made of a porous body at the time of filling and molding the powder in the mold. A powder compression molding method characterized by forcibly exhausting air in a mold through a hole.