JP2000301391A - Method for quantifying feed of powder in rotary powder compaction molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably feed powder of specified quantity by feeding the powder of at least the specified quantity to a mortar so as to rise above an upper surface of the mortar, projecting the tip of an upper pestle to press in the rising powder, returning the tip of the upper pestle to the original position again and leveling the remaining powder on the upper surface of the mortar. SOLUTION: A powder feed process comprises a feed process I, an adjustment process II, and a leveling process III. The powder P of a volume larger than the volume in a mortar 9 is fed into the mortar 9 to raise the powder higher than the upper surface of the mortar 9. An air cylinder 32 built in an upper pestle 11 is extended to project a pestle tip 11a and press the powder P. Cavities and bridges in the powder P in the mortar 9 are squeezed and the powder P of the quantity equal to the inner volume of the mortar 9 is filled. Then, the air cylinder 32 is contracted to return the pestle tip to the original position, the upper surface of the mortar 9 is leveled by a scraper S to remove the excessive powder P, and the powder P of the correct quantity is left behind in the mortar 9. The powder P in the mortar 9 is compacted by the upper pestle 11 and a lower pestle 12 to obtain a molded article whose weight density is within an allowable tolerance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for quantifying the amount of powder supplied to a rotary powder compression molding machine. More specifically, the present invention relates to a method for quantifying the amount of powder to be supplied to a die in a rotary powder compression molding machine that compresses powder to form a tablet or a material for electronic parts.

[0002]

2. Description of the Related Art One of typical rotary powder compression molding machines for molding tablets, materials for electronic parts and the like is constituted as follows. That is, in the frame, the rotating disk is supported by a vertical shaft so as to be freely rotatable horizontally, and a plurality of dies are provided at intervals on a peripheral portion of the rotating disk, and the upper punch and the lower punch are vertically moved corresponding to each die. It is configured to slidably hold, supply powder to the die with the rotation of the turntable, and then press the punch tips of the upper and lower punches into the die to compress and mold the powder filled in the die. I have.

However, in the above-mentioned powder compression molding machine, powder is supplied to the dies as shown in FIG. That is, first, as shown in the figure, the tip of the lower punch 12 is slightly inserted into the bottom of the mill 9, and the powder is filled into the mill 9 by free fall with an appropriate powder supply device. Then, as shown in the figure, the upper surface of the mill 9 is scraped off with a scraper S to quantify the supply amount, and then, as shown in the figure, the powder is pressed by an upper punch 11 and a lower punch 12 to remove the powder. I try to mold it into a tablet.

[0004]

By the way, as a powder of a tablet or an electronic component material molded by the above-mentioned powder compression molding machine, for example, the composition is about 70% of silica and about 30% of a resin such as an epoxy resin, and a very small amount. There is a substance in which carbon black is mixed in a small amount as a substance, and since these methods are thermosetting, they are formed by melting and solidifying and then pulverizing. In consideration of the economics of the pulverizing process, the powder particle size distribution of these powders varies widely from 50 μm to 2 mm. In this case, when there are many fine powders in the powder, as shown in FIG. Bridge d to powder in mortar
When a large amount of coarse particles is easily formed, as shown in FIG. 3B, a cavity h is easily formed in the mortar, and in any case, air is mixed between the powders (particles), There is a problem that it is difficult to supply a predetermined amount of powder to the apparatus.

[0005] Usually, in the case of tablet molding, the diameter is 9.8.
１８18 mm, height 7.7-31 mm, weight 4 g, but tolerances for product quality are within ± 3% by weight and 96% or more by constant tapping density. When h occurs, the above-mentioned tolerance is easily exceeded. Therefore, it is necessary to eliminate the bridge d and the cavity h in order to improve the yield and increase the production efficiency.

The present invention has been made in view of the above circumstances, and provides a method for quantifying the amount of powder supplied so as not to form bridges or cavities in the powder supplied into the die and to stably supply the powder in a constant amount. The purpose is to:

[0007]

According to a first aspect of the present invention, there is provided a method for quantifying a powder supply amount in a rotary powder compression molding machine, wherein a rotating disk is rotatably supported in a horizontal plane by an upright shaft, and the rotating disk is mounted on a peripheral portion of the rotating disk. While providing a plurality of mills at intervals,
A supply step of holding a plurality of upper punches and lower punches so as to be slidable up and down in association with each die, and supplying powder to the die with rotation of the turntable; In the rotary powder compression molding machine, which is configured to sequentially execute a molding step of compressing and molding the powder filled in the mortar, in the supply step, first, a certain amount or more of powder is swelled on the upper surface of the mortar in the mortar. And then push the punch tip of the upper punch to push in the protruding powder, return the punch tip of the upper punch to the original position again, and then slide the remaining powder on the upper surface of the mill. It is characterized by cutting.

According to a second aspect of the present invention, there is provided a method for quantifying a powder supply amount in a rotary powder compression molding machine, wherein a rotating disk is rotatably supported in a horizontal plane by an upright shaft, and a plurality of dies are provided at intervals on a peripheral portion of the rotating disk. A supply step of holding a plurality of upper punches and lower punches slidably up and down in association with the respective dies, and supplying powder to the dies with rotation of the turntable; and an upper punch and a lower punch. In the rotary powder compression molding machine that was pressed into the mortar and pressed the molding process of compressing the powder filled in the mortar in order, in the supplying step, first, a fixed amount or more powder in the mortar The lower punch is inserted so that it rises up to the upper surface of the mortar, and then the lower punch into which the tip of the punch is inserted is quickly lowered to a predetermined position or rapidly lowered, and then returned to the original position again. It is characterized in that the remaining powder on the upper surface is slid off.

According to a third aspect of the present invention, there is provided a method for quantifying a powder supply amount in a rotary powder compression molding machine, wherein a rotating disk is rotatably supported in a horizontal plane by an upright shaft, and a plurality of dies are provided at intervals on a peripheral portion of the rotating disk. A supply step of holding a plurality of upper punches and lower punches slidably up and down in association with the respective dies, and supplying powder to the dies with rotation of the turntable; and an upper punch and a lower punch. In the rotary powder compression molding machine that was pressed into the mortar and pressed the molding process of compressing the powder filled in the mortar in order, in the supplying step, first, a fixed amount or more powder in the mortar Then, the lower punch with the tip of the punch inserted into the mill is vibrated up and down, then stopped again at the original position, and then the remaining powder on the upper surface of the mill was slid. It is characterized by cutting.

[0010]

Next, embodiments of the present invention will be described with reference to the drawings. First, a schematic configuration of a rotary powder compression molding machine to which the supply amount quantification method of the present invention is applied will be described. FIG. 4 is a vertical sectional view of a main part of the powder compression molding machine, and FIG. 5 is a developed view for explaining the compression molding operation.

In FIG. 4, reference numeral 1 denotes an upright shaft, which is rotatably supported by a frame 4 via bearings 2 and 3, and a lower end of the upright shaft 1 is connected to a motor 6 with a reducer by a joint 5. A rotating disk 7 is fixed to the upper end of the upright shaft 1, and is rotatably supported by a bearing 8 with respect to the frame 4. Therefore, the rotating disk 7 is rotated at a predetermined rotational speed in a horizontal plane by the driving of the motor 6.

The rotary disk 7 is a substantially disk-shaped member in a plan view, and its peripheral edge is provided with holes at regular intervals in the circumferential direction, and a die 9 is attached thereto. Number of mortar 9 is usually several tens
The powder is supplied by a predetermined amount by a powder supply mechanism (not shown). A plurality of upper punches 11 and lower punches 12 are provided in association with the respective dies 9, and these are supported slidably in the vertical direction by an upper holding portion 13 and a lower holding portion 14 formed on the rotating disk 7. Have been.

On the other hand, the upper punch 11, the lower punch 12, and the mill 9 rotate in a horizontal plane with the rotation of the turntable 7. During one rotation, the powder is supplied, compressed, and formed. It is configured to take out. That is, as shown in FIG. 5, in the powder supply step A, the upper punch 11 is held above the die 9 by the guide rail 21 via the roller 11A, and the powder is supplied to the die 9 by a powder supply mechanism (not shown). During this time, the lower punch 12 is supported by a guide rail 22 via a roller 12A, and the guide rail 22 is set at a predetermined position by a worm jack (not shown). To receive the supplied powder. Then, at this stage, the supply amount quantification method of the present invention is performed, and the details will be described later.

Next, the upper punch 11 is gradually lowered, and the upper punch 11 and the lower punch 12 are slightly pushed into the die 9 by the upper pressure roll 17 and the lower pressure roll 18 for preloading. An upper punch 11 and a lower punch 12 are formed by a pressure roll 15 and a lower pressure roll 16.
Is pressed into the mortar 9 (see also the left side of FIG. 1), and the powder in the mortar 9 is compressed with a compressive force of several tons to form a column.

After that, the upper punch 11 is pulled up by the guide rail 21 and the lower punch 12 is inserted to the upper end of the die 9 by the push-up roll 19 to take out the formed product G upward.
It is discharged to the outside by a discharge device not shown. After that, a process such as release agent spraying is executed, and one cycle is completed.

Next, each embodiment of the supply amount quantification method will be described. FIG. 1 shows the first method of the present invention.
It is a process drawing showing an embodiment. As also shown in FIG. 5, the powder supply step A includes a supply step I, an adjustment step II, and a sliding step III.

In the supply step I, a larger amount of powder is supplied into the die 9 than the volume in the die 9 so that the powder is raised above the upper surface of the die 9. Subsequently, in the adjustment step II, the air cylinder 32 incorporated in the upper punch 11 is extended to make the punch tip 11a protrude to lower the raised powder.
Even if a cavity or a bridge is formed in the powder in the mortar 9 by this rolling operation, the powder is crushed and filled with the same amount of powder as the inner volume of the mortar 9.

Thereafter, the air cylinder 32 is contracted to return the tip of the punch to its original position, and the process proceeds to the cutting process III. When the upper surface of the dies 9 is slid with the scraper S, excess powder is removed. The exact amount of powder will be left within. Thereafter, the molding process is started, and as described above, the upper punch 11 and the lower punch 1
When the powder in the mortar 9 is compressed at 2, the amount of the powder is accurately quantified, so that the weight density is formed into a product within the allowable error range.

In the adjusting step II, if the pressing pressure of the upper punch 11 is too high, the filling amount of the powder will not be accurate, so it is necessary to control the pressing pressure not to become higher than necessary. Therefore, for example, it is preferable to adjust the pressure of the air supplied to the air cylinder 32 to the upper punch 11 or incorporate a spring to reduce the pushing force. The means for adjusting the pushing force is not limited to the air pressure adjustment and the spring, but any means may be used as long as the object can be achieved.

FIG. 2 is a process chart showing a second embodiment of the supply amount quantification method of the present invention. In FIG.
Since the sliding step III is the same as that of the first embodiment, only the adjusting step II will be described.

In the adjusting step II of the present embodiment, the lower punch 12 is lowered rapidly after the powder is supplied in the supplying step I (II-
1) Perform an operation of holding the position (II-2). Alternatively, it may be quickly lowered and then returned to the original position.
The sudden drop of the lower punch 12 shocks the powder in the mortar 9, thereby crushing the bridges and cavities in the mortar 9.

In the present embodiment, any means may be used for rapidly lowering the lower punch 12 without particular limitation. For example, a means for rapidly lowering the lower punch 12 with a cylinder attached to the lower punch 12 or the lower holding portion 14 can be exemplified. .

FIG. 3 is a process diagram showing a third embodiment of the supply amount quantification method of the present invention. Since the supply step I and the sliding step III in the same drawing are the same as those in the first embodiment,
Here, only the adjustment step II will be described.

In the adjusting step II of this embodiment, the lower punch 12 is vibrated up and down (II-2) after the powder is supplied in the supplying step I (II-1). Next, an operation of returning the lower punch 12 to its original fixed position, that is, a position where the tip of the punch is slightly inserted into the bottom of the mill 9 is performed (II-2). Since the vertical vibration of the lower punch 12 gives a shock to the powder in the mortar 9, the bridge or cavity in the mortar 9 is crushed by this movement.

In the present embodiment, any means may be used for oscillating the lower punch 12 without any particular limitation.
Guide rail 2 supporting lower punch 12 in adjustment process II
The exciter 22B may be provided on the 2A, or a worm jack (not shown) for raising and lowering the guide rail 22A may be supported on the exciter (not shown).

[0026]

According to the first aspect of the present invention, the raised powder is pressed down with the upper punch to eliminate cavities and bridges. According to the second aspect of the present invention, the lower punch is rapidly lowered. According to the third aspect of the present invention, the cavity and the bridge generated in the powder in the mill can be eliminated by vibrating the lower punch. According to the invention, a precise amount of powder can be filled in the die. Therefore, the weight and density of the compression-molded article become uniform, and molding defects can be eliminated to increase the yield.

[Brief description of the drawings]

FIG. 1 is a process chart showing a first embodiment of a supply amount quantification method of the present invention.

FIG. 2 is a process chart showing a second embodiment of the supply amount quantification method of the present invention.

FIG. 3 is a process chart showing a third embodiment of the supply amount quantification method of the present invention.

FIG. 4 is a longitudinal sectional view of a main part of a powder compression molding machine in which the method for quantifying the amount of supplied powder according to the present invention is performed.

FIG. 5 is a development view illustrating a compression molding operation in the powder compression molding machine of FIG.

FIG. 6 is a view showing a conventional powder supply method.

FIG. 7 is an explanatory view showing a problem of a conventional powder supply method, wherein FIG. 7A shows a bridge d formed in a die, and FIG.
The figure is a diagram showing a cavity h formed in the die.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vertical shaft 7 Rotating disk 9 Die 11 Upper punch 12 Lower punch 15 Upper press roll 16 Lower press roll A Powder supply process I Supply process II Adjustment process III Sliding cutting process

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ojiji Hirata 2-5-8 Higashishinagawa, Shinagawa-ku, Tokyo Sumitomo Bakelite Co., Ltd. F-term (reference) 4G068 AA02 AA04 AA05 AB22 AD23 AD32

Claims (3)

[Claims] 1. A rotating disk is rotatably supported in a horizontal plane by an upright shaft, a plurality of dies are provided at intervals on a peripheral portion of the rotating disk, and a plurality of upper punches and lower punches are associated with the respective dies. Holding the punch so that it can slide up and down, supplying the powder to the die with the rotation of the turntable, and pushing the punch tips of the upper and lower punches into the die to compress the powder filled in the die. In a rotary powder compression molding machine that is configured to sequentially perform a molding step of molding, in the supplying step, first, a predetermined amount or more of powder is supplied to the die so as to swell on the upper surface of the die, and then the tip of the upper punch is To push out the protruding powder and return the tip of the upper punch to its original position again.
Thereafter, a powder supply amount quantification method in a rotary powder compression molding machine, characterized in that the remaining powder on the upper surface of the mortar is slid off. 2. A rotating disk is rotatably supported in a horizontal plane by an upright shaft. A plurality of dies are provided at intervals on a peripheral portion of the rotating disk, and a plurality of upper punches and lower punches are associated with the respective dies. Holding the punch so that it can slide up and down, supplying the powder to the die with the rotation of the turntable, and pushing the punch tips of the upper and lower punches into the die to compress the powder filled in the die. In the rotary powder compression molding machine so as to sequentially perform the molding step of molding, in the supply step, first supply a certain amount or more of powder to the mortar so as to rise to the upper surface of the mortar, and then into the mortar Rotary powder compression characterized by rapidly lowering or lowering the lower punch into which the punch tip has been inserted to a predetermined position, and then returning it to its original position, and then sliding the remaining powder on the upper surface of the die. Method for quantifying powder supply in molding machine. 3. A rotating disk is rotatably supported in a horizontal plane by a vertical shaft, a plurality of dies are provided at intervals on a peripheral portion of the rotating disk, and a plurality of upper punches and lower punches are associated with the respective dies. Holding the punch so that it can slide up and down, supplying the powder to the die with the rotation of the turntable, and pushing the punch tips of the upper and lower punches into the die to compress the powder filled in the die. In the rotary powder compression molding machine so as to sequentially execute the molding step of molding, in the supply step, first supply a certain amount or more of powder to the mortar up to the upper surface of the mortar,
Next, after vibrating the lower punch in which the tip of the punch is inserted into the mortar up and down, stop again at the original position, and then slide the remaining powder on the upper surface of the mortar, and the rotary powder A method for quantifying the amount of powder supplied in a compression molding machine.