JPH10180493A - Powder compacting device and compacting method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a powder compacting device and its powder compacting method where the dispersion of supplying a powder to a die is eliminated and an uniform green compact can be obtained. SOLUTION: A regulating opening tube 6 connected to a powder supplying tube 5 is installed inside a feeder 4 except one part or all of an upper lid, at every pressing, the feeder 4 is advanced or retreated and the powder 9 is supplied to a space formed with a die 3 and a lower punch 2. In this time, because there is no upper lid, the air of the space is easily discharged, and the powder supplying amount inside the feeder is regulated properly with the volume of the regulating opening tube 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a powder molding apparatus and a molding method using the same, and more particularly, to a structure of a feeder for supplying powder to a powder molding die and a powder molding method using the same.

[0002]

2. Description of the Related Art A conventional technique will be described below.

[0003] The powder compacting method is a technique of directly compacting a metal or ceramic powder as a raw material into a final product or a shape close to the final product. Compared with the law, it has excellent economic efficiency and mass productivity. As a method for imparting the shape of a product, a die press molding method is most widely used.

[0004] In recent years, the requirements for dimensional accuracy of sintered parts have become strict, and the variation in the green density of the green compact has been reduced.
It is important to equalize the density of each compact, and a high-precision powder molding method is required.

As shown in FIG. 2, the conventional powder molding apparatus includes an upper punch 1, a lower punch 2, a die 3, and a box-shaped powder feeder 4.

[0006] The feeder 4 for powder supply includes an upper lid 7.
And a lower end opening 8a for supplying powder 9 to a space 8 formed by the powder supply pipe 5 and the die 3 and the lower punch 2 at the lower end.

In the powder molding, the die 3 is raised while the lower punch 2 is fixed using these devices, the feeder 4 is advanced, and the powder 9 is filled in the space 8 formed by the die 3 and the lower punch 2. I do.

[0008] Thereafter, the feeder for powder supply retreats, the upper punch descends, and a powder compact is obtained by compression molding the powder.

[0009]

In the conventional powder compacting apparatus, the powder flowing from the powder supply pipe in the feeder fills the feeder, so that powder jamming and a bridging phenomenon are likely to occur.

Further, since the replacement of the powder and the air in the mold die is not easily performed, and there is no escape space for the air, the powder becomes difficult to flow and the supply of the powder varies. As a result, there has been a problem that the green density varies and the dimensional accuracy of the sintered body is reduced.

In particular, a molded article having an elongated shape,
For those with a deep bottom shape, the tendency is remarkable, and there is also a difference in green density within each green compact,
Deformation after sintering has also been a problem.

In a conventional powder molding machine, the amount of rise of a die is set so as to be several percent larger than a predetermined filling amount, and after the powder is filled from the feeder, when the feeder is retracted, the predetermined filling amount is reduced. return. By doing so, the powder filled by several percents is pushed back into the feeder. With this method, it is possible to prevent defective filling at the die filling end and the like. However, since the powder is partially compacted in the conventional powder supply feeder, powder jams and a bridging phenomenon occur, and the powder cannot be supplied stably.

The present invention solves the above problems by improving a box-shaped powder supply feeder and devising a powder molding method, thereby eliminating variations in powder supply to dies and achieving high accuracy. An object of the present invention is to provide a powder molding apparatus having a box-shaped powder supply feeder capable of obtaining a uniform green compact, and a powder molding method using the same.

[0014]

According to the present invention, in a powder molding apparatus having an upper punch, a lower punch, a die, and a feeder as a basic structure, part or all of an upper lid of a box-shaped powder supply feeder is removed. And a powder molding apparatus having an adjusting mechanism for adjusting the amount of powder supplied into the feeder, and a powder molding method using the powder molding apparatus.

In the powder molding apparatus of the present invention, as shown in FIG. 1, a box-shaped powder supply having an adjustment opening pipe 6 for adjusting the powder supply amount except for a part (not shown) or all of the upper lid. The feeder moves forward and backward each time the press operation is performed in the direction of the arrow, and supplies the powder 9 to the space 8 formed by the die 3 and the lower punch 2.

The amount of powder to be stocked in the feeder is adjusted and determined by the adjustment opening pipe 6 connected to the powder supply pipe 5 for adjusting the amount of powder supplied by supplying the amount of the adjustment opening pipe. It has become.

The powder stocked in the feeder is
When supplied to the space 8 filled with the powder formed by the die 3 and the lower punch 2, the powder falls naturally, but the air in the die 3 is discharged to the outside because there is no part or all of the upper lid in the feeder. You.

For this reason, the replacement of the air inside the die with the supply powder becomes easy. Therefore, dust is reduced,
A powder without bridging is provided. The powder 9 supplied to the space 8 formed by the die 3 and the lower punch 2 is supplied from the powder supply pipe 5 to the feeder 5 by a reduced amount through the adjustment opening pipe 6 when the feeder is retracted. .
For this reason, the amount of powder stock in the feeder can always be kept constant.

The amount of powder supplied to the die 3 is determined by the amount of rise of the die. The amount of powder supplied is about 10% larger than a predetermined filling amount, the feeder 4 is advanced, and the powder 9 is filled in the die 3. Next, just before the feeder retreats, the die 3 is lowered to a predetermined filling amount. At this time, the excessively filled powder is returned into the feeder. afterwards,
The feeder 4 cuts the powder 9 on the upper surface of the die while moving backward.

In the powder molding apparatus of the present invention, since the supply powder and air can be replaced in the feeder and the amount of powder supplied can be adjusted, it is possible to prevent poor filling occurring at the end of the space for supplying powder. Thus, variation in powder filling is suppressed, and a high-quality green compact can be obtained.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 3 is an operation diagram showing a powder molding method by the powder molding apparatus of the present invention.

In FIG. 3, a feeder 4 for supplying powder installed on a die 3 has a powder supply pipe 5 and an opening pipe 6 for adjusting the amount of powder stock, and has a structure excluding an upper lid.

At the time of powder molding, only the powder 9 is supplied into the feeder 4 by the adjusting opening pipe 6 for adjusting the amount of powder supplied from the powder supply pipe 5. When the powder is supplied, the feeder advances to the space 8 formed by the die 3 and the lower punch 2, and the powder 9 in the feeder is supplied to the space 8 in the die.

In the space formed by the die 3 and the lower punch 2, when the feeder 4 moves forward, the amount of powder filling is set to be 10% larger than the supply amount. When powder is supplied to this space, the powder and air are replaced. At that time, the air is easily discharged to the outside from the upper opening 10 of the feeder 4.

When the supply of the powder is completed, the feeder 4 starts to retreat. At the same time, the powder supplied into the die 3 is pushed back into the 10% feeder 4 by lowering the die 3. After the feeder 4 is further retracted, the adjustment opening pipe 6 is moved from the powder supply pipe 5 at the rear of the feeder.
Supplies the consumed amount of powder.

A compact was obtained by a molding method using the powder compacting apparatus according to the embodiment of the present invention, and was sintered.
As a result of examining the dimensional variation of the obtained sintered body, the results as shown in Table 1 were obtained. For comparison, compacts were obtained by a compacting method using a conventional powder compacting apparatus and were sintered. The results are shown in Table 1.

[0028]

According to Table 1, the dimensional variation of the conventional product is
The product of the present invention was able to reduce the variation by about 26%.

[0030]

According to the present invention, there is provided a powder molding apparatus having a basic structure including an upper punch, a lower punch, a die, a feeder, and the like, in which a part or all of an upper cover of a box-shaped powder supply feeder is removed. The powder molding apparatus having the powder supply adjusting mechanism in the feeder and the powder molding method using the same can provide a high-quality sintered body with less variation in powder supply.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a powder molding apparatus according to the present invention. FIG.
(A) is a front sectional view showing a configuration of a powder molding device of the present invention. FIG. 1B is a side sectional view showing a configuration of the powder molding apparatus of the present invention.

FIG. 2 is a side sectional view showing a configuration of a conventional powder molding apparatus.

FIG. 3 is an operation diagram showing a powder molding method by the powder molding device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper punch 2 Lower punch 3 Dice 4 Feeder 5 Powder supply pipe 6 Adjustment opening pipe 7 Top lid 8 Space 8a Lower end opening 9 Powder 10 Upper opening

Claims (4)

[Claims] 1. A powder molding apparatus having an upper punch, a lower punch, a die, and a feeder as a basic structure, wherein the powder molding apparatus has a structure in which part or all of an upper lid of the feeder is removed. 2. A powder molding apparatus having an upper punch, a lower punch, a die, and a feeder as a basic structure, wherein a powder stock amount adjusting mechanism is provided in the feeder. 3. A powder molding apparatus having an upper punch, a lower punch, a die, and a feeder as a basic structure, wherein a part or all of an upper lid of the feeder is removed, and a powder stock amount adjusting mechanism is provided in the feeder. A powder molding apparatus characterized by the above-mentioned. 4. A molding method using a powder molding apparatus provided with a powder adjusting opening pipe connected to a powder supply pipe in a feeder except for a part or the whole of an upper lid of a feeder, wherein a press operation is performed. Each time, when the feeder moves forward and backward to supply the powder into the space filled with the powder formed by the die and the lower punch, the air in the space in the die is easily discharged, and the powder supply amount is adjusted. A powder molding method using the powder molding apparatus according to any one of claims 1 to 3, wherein the amount of powder stock in the feeder is adjusted by adjusting the volume of the opening tube for use.