JPH03119000A - Compacting method for powder and die assembly for compacting powder - Google Patents

Abstract

PURPOSE:To uniformize compacting density and to prevent a crack from being generated by adjusting the relative height of partitioned parts of a lower die to reduce the ruggedness on the upper surface of the lower die when powder is supplied between dies. CONSTITUTION:First of all, the powder WO is supplied into a container 23 as a 1st lower die 21-1 is positioned downward. The upper surface of the powder WO supplied is nearly a plane and sine the 1st lower die 21-1 is located at a lower position, the rate of ruggedness on the upper surface of the lower die is small. Thereafter, the 1st lower die 21-1 is moved upward by a vertical cylinder 41 for the lower die and wedges 42 are inserted by a wedge push/pull cylinder 43 under the 1st lower die 21-1. In this way, the 1st lower die 21-1 is fixed to the proper high position. At the same time, the 2nd lower dies 21-2, too, are fixed. Consequently, the powder WO in the container 23 is accumulated uniformly along the rugged shape of the upper surface of the proper lower die 21 and the rugged shape of the lower surface of the upper die 22 and the powder is pressurized uniformly at a compacting time.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a powder molding method in which powder supplied between a lower mold and an upper mold is pressurized to mold an undulating shaped molded product. , and a mold apparatus for powder molding for carrying out the method.

[Prior Art] As a mold device for powder molding, mold devices for powder molding as shown in FIGS. 7 to 10 have been proposed.

This mold device is set on the bed 1 of the powder molding device 10, as indicated by the reference numeral 20. The mold device 20 has a powder pre-pressing function, and after pre-pressing the powder, it is pressurized by the pressure cylinder 2 of the powder molding device ft1o.

In the powder forming apparatus 10, the pressure cylinder 2 is provided on a crown 3, and the crown 3 is supported above the bed 1 by a column 4. A spherical seat 6 is tiltably attached to the lower end of the pressure ram 5 built into the pressure cylinder 2, and this spherical seat 6 presses the mold device 20 downward via the spacer block 7. It looks like this. 8 to 10 are enlarged views of the mold device 20. FIG.

The mold apparatus 20 is equipped with a lower mold 21 and an upper mold 22, which are vertically opposed to each other with a rectangular container 23 in which the powder WO to be pressure molded is placed. The lower mold 21 and the upper mold 22 have predetermined curvatures R1 and R2 (
Curved surfaces 21a and 22a (see FIG. 8) are formed, and flat surfaces 21b and 22b are formed on the left and right sides of the curved surfaces 21a and 22a.
is formed, and by pressurizing the powder WO between these, the undulating shape shown with vertical lines in FIGS. 8 and 9, that is, the center swells. With this, it is possible to mold a molded product w1 having a cross-sectional shape that is flat on both sides.

The lower mold 21 is fixed on a base plate 24, and is connected to a flat surface 21c provided around the entire upper surface of the lower mold 21 and a container 23.
The lower end surfaces of the two are brought into contact and sealed.

On the other hand, the upper mold 22 is attached to the lower end of a slider 26 via a pressure block 25, and the slider 26 is supported by a column 27 erected on the base plate 24 so as to be slidable in the vertical direction. In FIG. 8, 28 is a sliding guide liner of the slider 26. Further, the container 23 is also supported by a column 27 so as to be slidable in the vertical direction, and 29 is a sliding guide liner of the container 23. Further, on the base plate 24, as shown in FIG. 10, a pre-pressure cylinder 30 that moves the slider 26 up and down together with the upper mold 22, and a container shift cylinder 31 that moves the container 23 up and down are provided.

Further, a supply hopper 32 is connected to the container 23, and the powder WQ is supplied into the container 23.

The mold device 20 configured in this manner supplies the powder WQ into the container 23 and then presses the upper mold 22 downward by the prepressing cylinder 30 to prepress the powder WO.

After that, by the pressure cylinder 2 of the powder molding device IO,
The mold device 20 is pressurized to pressurize the powder WQ to form the final molded product W1.

To take out the molded product Wl, first, the container 23 is slightly shifted upward by the container shift cylinder 31 to separate the container 23 upward from the molded product W1. after that,
The pressure cylinder 2 of the powder molding device 10 is contracted, and the pre-pressure cylinder 30 of the mold device 10 is extended, thereby separating the upper mold 22 upward from the molded product W1.

By the way, before pressurizing the powder WQ, the container 23
The powder WQ supplied into the mold 22 is in a state as shown by the dotted line in FIG.
It is impossible to feed powder into a shape similar to the curved surface 22a of the curved surface 22a. Therefore, when pressurizing the powder WO, first, by gradually lowering the upper mold 22, the volumes of the A1 part and the A2 part at the two left and right locations are reduced at the intermediate position as shown by the two-dot chain line in FIG. When we consider the position where are equal, we expect that the powder in part A1 will move to part A2.

[Problems to be Solved by the Invention] However, the movement of the powder as described above cannot be expected in practice, and most of the powder in the A1 section is in the upper and lower molds 21, 22.
It had been absorbed in the compression direction between. Therefore, the movement to the A2 portion was small, and the final pressure-formed molded product W1 had a non-uniform density, which sometimes caused cracks.

The purpose of this invention is to solve these problems and provide a powder molding method that makes the density of the molded product uniform and eliminates the occurrence of cracks, and a mold device for powder molding. shall be.

[Means for Solving the Problems] (1) The method for molding powder of the present invention includes pressurizing powder supplied between a lower mold and an upper mold to mold a molded product with an undulating shape. In the method for molding a powder, the lower mold is divided into a part facing a high position part of the lower surface of the upper mold and a part facing a low position part of the lower surface of the upper mold, and When feeding, the relative height of the divided parts of the lower mold is adjusted to reduce the undulations on the upper surface of the lower mold, and then the divided parts of the lower mold are restored to their normal height. Then, the powder is pressure-molded between a lower mold and an upper mold.

(2) The mold device for powder molding of the present invention is a mold device for powder molding that presses powder between an upper mold and an upper mold to form an undulating shaped molded product. The lower mold is divided into a portion facing a high position portion of the lower surface of the upper mold and a portion facing a low position portion of the lower surface of the upper mold, and It is characterized by comprising a driving means for moving at least one of the divided parts downward.

[Function] In this invention, the lower mold is divided into a part facing the high position part of the lower surface of the upper mold and a part facing the low position part of the lower surface of the upper mold, and there is no space between the molds. When supplying powder, adjust the relative height of the divided parts of the lower mold to reduce the undulations of the upper surface of the lower mold (by doing so, after supplying the powder, the divided parts of the lower mold When the mold is returned to its original height, the powder is deposited uniformly on both sides of the lower mold.

During pressure molding of powder, the powder uniformly deposited on the upper surface of the lower mold is filled between the upper and lower molds at a uniform density, and the powder is evenly pressurized to achieve a compacting density. Molding high-quality molded products with uniformity and no cracks.

[Example] Hereinafter, an example of the present invention will be described based on FIGS. 1 to 6. The illustrated embodiment is different from the conventional one described above.
This is an example of application as a mold device for pressure-molding a molded product Wl similar to the above. Therefore, the same reference numerals are given to the same parts as in the conventional example described above, and the description thereof will be omitted.

1 to 3 are diagrams for explaining a first embodiment of the present invention.

In this embodiment, the lower mold 21 is divided into two parts: a part of the lower mold 22 opposite to a high position part of the lower surface of the upper mold 22, that is, a part of the relatively high central curved surface 21a that swells upward, and a lower part of the lower surface of the upper mold 22 It is divided into three parts, ie, relatively low flat surfaces 21b located on the left and right sides of the curved surface 21a, and the relatively high central curved surface 21a is movable up and down. Therefore, in the lower mold 21, the curved surface 21a
The parts corresponding to the first lower mold 21-1, the left and right planes 2
A portion corresponding to 1b is defined as a second lower mold 21-2. In addition, in FIG. 3, the reference numeral 21-3 indicates the first lower mold 21.
- a third lower mold located before and after the third lower mold;
The lower mold 21-3 and the second lower mold 21-2 are fixed on the base plate 24 to form a rectangular shape, and the first lower mold 21-1 is located in the center surrounded by these. It is combined so that it can be moved up and down.

The first lower mold 21-1 is provided with a lower mold elevating cylinder (driving means) 41 that moves it up and down.

Further, on the base plate 24, the first lower mold 21-
A locking mechanism is provided to lock 1 in the upwardly moved position. In the case of this example, this fixing mechanism is the first lower mold 21
By inserting a wedge 42 under the mold 21-1, the lower mold 21-1 is fixed. Corresponding tapered surfaces 42a and 2l-1a are formed on the upper surface of the wedge 42 and the lower surface of the first lower mold 21-1, and as shown in FIG. By inserting the lower mold 2l-1H under the first lower mold 2l-1H, the lower mold 2l-1a is fixed. Further, a tapered surface 2l-2a is also formed on the lower surface of the second lower mold 21-2, and when the wedge 42 is inserted as shown in FIG. It can be fixed.

Next, a method of molding powder using such a mold device will be described.

First, powder WO is supplied into the container 23 with the first lower mold 21-1 positioned downward as shown in FIG.

The upper surface of the supplied powder WO becomes substantially flat as shown in the figure. Note that at this time, since the first lower mold 21-1, which should originally be at a high position, is at a low position, the degree of undulation of the upper surface of the lower mold is small.

Thereafter, as shown in FIG. 2, the first lower mold 21-1 is moved upward by the lower mold lifting cylinder 41, and the wedge 42 is moved upward by the wedge push/pull cylinder 43. Insert it under the. This allows the first
The lower mold 21-1 is fixed at its original high position.

At the same time, the second lower mold 21-2 is also fixed. By moving the first lower mold 21-1 to its original high position, the powder WO in the container 23 is changed to the original undulating shape of the upper surface of the lower mold 21 and the upper This results in uniform deposition along the undulating shape of the lower surface of the mold 22.

Thereafter, as in the case of the conventional example described above, the upper mold 22 is pressurized downward by the pre-pressure printer 30 (see FIG. 10) to pre-press the powder WO.

Thereafter, the mold device 20 is pressurized by the pressure cylinder 2 of the powder molding device (see FIG. 7), and the powder WO is pressurized to form the final molded product W1. In addition, during such pressure molding, since the powder WQ deposited to a substantially uniform thickness between the lower molds 21 and 22 is pressurized, the final pressure molding The product W1 has a uniform density and no cracks occur.

The removal of the molded product W1 is the same as in the conventional example described above.

FIGS. 4 to 6 are diagrams for explaining a second embodiment of the present invention.

In this embodiment, contrary to the first embodiment described above,
The first lower mold 21-1 is fixed on the base plate 24, and the second and third lower molds 21-2.21- have a rectangular shape.
3 can be moved up and down.

That is, the first lower mold 21-1, which is originally at a high position facing the high position part of the upper mold 22, is fixed, and the first lower mold 21-1, which is originally at a high position facing the high position part of the upper mold 22, is fixed, and Someone's second. The third lower mold 21-2 and 21-3 are movable up and down. In the figure, 44 is a lower mold lifting cylinder (driving means); Third lower mold 21-2.21-3
are arranged on the base plate 24 so as to move up and down integrally.

In addition, the container shift cylinder (9th
(see figure) 31 is controlled in relation to the lower mold lifting cylinder 44. That is, the second. When the third lower mold 21-2, 21-3 moves between the upper position shown in FIGS. 4 and 6 and the lower position shown in FIG. The container 23 is designed to move up and down. Moreover, when they are moved to the lower position, as shown in FIG. Third lower mold 21
-2.21-3 is placed on the base plate 24 and fixed.

Next, a method of molding powder using such a mold device will be described.

First, as shown in FIGS. 4 and 6, the second. Powder WO is supplied into the container 23 with the third lower mold 21-2, 21-3 positioned above. The upper surface of the supplied powder WQ becomes substantially flat as shown in the figure. In addition, at this time, the second. Third lower mold 21-
2. Since 21-3 is located at a high position, the degree of undulation of the upper surface of the lower mold is small.

Thereafter, as shown in FIG. The third lower mold 21-2, 21-3 is moved downward, and the container 23 is also moved downward. As a result, the second. The third lower mold 21-2, 21-3 and the container 23 are fixed at their original, normal low positions. Second. By moving the third lower mold 21-2, 21-3 to its original low position, the powder WO in the container 23 is removed.
is deposited uniformly along the original undulating shape of the upper surface of the lower mold 21 and the undulating shape of the lower surface of the upper mold 22, as shown in FIG.

Thereafter, as in the case of the first embodiment described above, the powder WQ is pre-pressed and pressurized to form the final molded product wl. Therefore, during pressure molding, the powder WQ deposited to a substantially uniform thickness between the upper and lower molds 21 and 22 is pressurized and finally pressure molded. The molded product W1 has a uniform density and no cracks occur.

The removal of the molded product W1 is the same as in the conventional example described above.

In addition, in the embodiment described above, the lower mold 21 is placed in the first mold.
Second. Third lower mold 21-1.21-2゜21-3-3
It is divided into two parts, but the number of divisions is not specified and is arbitrary. The key is to divide the lower mold into a part that faces the high part of the lower surface of the upper mold and a part that faces the lower part of the lower surface of the upper mold, and supply powder between the molds. When doing so, it is sufficient to reduce the overall undulations of the upper surface of the lower mold by lowering the originally high portion of the upper surface or raising the portion where the upper surface is originally low.

In addition, in the first embodiment, when using a lower mold in which the lower mold 21-1 is divided into a plurality of parts according to the height of the lower surface of the upper mold, the lower mold is By raising the part closest to the mold 21-2 to the original height, the powder on the lower mold is pushed into the recessed part of the lower surface of the upper mold, and the powder of the upper and lower molds is moved. It is also possible to fill the space more uniformly with powder.

Further, the shapes of the upper and lower molds may be any shape as long as they can mold an undulating molded product, and are not limited to the shapes of the above-described embodiments.

Further, as the driving means for vertically moving the divided lower mold parts, various mechanisms other than a hydraulic cylinder can be employed, and the present invention is not limited to the same structure as in the above-described embodiment.

Further, as a modification of this invention, there are the following examples.

In other words, in the case of a mold device that molds an undulating shaped product with partially different thicknesses by using an upper mold with a flat bottom surface and a lower mold with an undulating upper surface, the lower mold is It is divided into a part where the top surface is at a low position and a part where the top surface is at a high position, and when feeding the powder between the molds, the former part is raised or the latter part is lowered. As a result, the shape of the powder deposit during pressure molding is made into a shape that approximately corresponds to the molding space between the upper and lower molds, and then, by restoring the divided portion of the lower mold to its original regular position,
It is also possible to achieve uniform pressurization of powder.

[Effects] As explained above, the present invention divides the lower mold into a portion that faces a high-position portion on the lower surface of the upper mold and a portion that opposes a low-position portion of the lower surface of the upper mold. , when feeding powder between the molds, the relative height of the divided parts of the lower mold is adjusted to reduce the undulations of the upper surface of the lower mold (so that after supplying the powder, the lower When the divided parts of the mold are restored to their original normal heights, the powder can be deposited uniformly on the upper surface of the lower mold.

Therefore, during pressure molding of powder, it is possible to fill the space between the upper and lower molds with powder of uniform density and press the powder uniformly.As a result, the molding density is uniform and cracks are avoided. It is possible to mold high-quality molded products that do not cause such problems.

[Brief explanation of drawings]

1 to 3 are diagrams for explaining the first embodiment of the present invention, in which FIG. 1 is a longitudinal cross-sectional view of the main part during supply of powder, and FIG. FIG. 3 is a longitudinal cross-sectional view of the main part during pressurization, and is a cross-sectional view taken along the line ■-■ in FIG. 1. 4 to 6 are diagrams for explaining a second embodiment of the present invention, in which FIG. 4 is a vertical cross-sectional view of the main part during supply of powder, and FIG. FIG. 6 is a longitudinal cross-sectional view of the main part during pressurization, and is a cross-sectional view taken along the line ■-VI in FIG. 4. Figures 7 to 10 are diagrams for explaining conventional examples of mold equipment, in which Figure 7 is a side view of the powder molding equipment with the mold equipment set, and Figure 8 is the mold FIG. 9 is an enlarged longitudinal sectional view of the mold device, and FIG. 10 is an enlarged side view of the mold device. 10...Powder molding device, 20...Mold device, 2I...Lower mold, 21a...
Curved surface, 21b...Flat surface, 21-1...First lower mold (portion facing the high position part of the upper mold), 21-2...First 2 lower mold (the part facing the lower part of the upper mold), 21-3...Third lower mold, 22...Upper mold, 22a...・Curved surface, 22b...
・Plane, 23...Container, 24...
... Base plate, 41.44 ... Lower mold lifting cylinder (drive means), WO ... Powder, w
t... Molded product.

Claims (2)

[Claims] (1) Pressurize the powder supplied between the lower mold and the upper mold,
In the powder molding method for molding a molded article having an undulating shape, the lower mold is arranged such that a portion of the lower mold faces a high position portion of the lower surface of the upper mold and a lower portion of the lower surface of the upper mold faces the low position portion. When feeding the powder, the relative height of the divided parts of the lower mold is adjusted to reduce the undulations on the upper surface of the lower mold, and then the divided parts of the lower mold are divided into two parts. A powder molding method characterized by restoring the powder to its normal height and then pressure molding the powder between a lower mold and an upper mold. (2) In a powder molding mold device that presses powder between a lower mold and an upper mold to form an undulating shaped molded product, the lower mold is connected to the upper mold. A driving means that is divided into a portion facing the high-position portion of the lower surface and a portion facing the low-position portion of the lower surface of the upper mold, and for vertically moving at least one of the divided portions of the lower mold. A mold device for powder molding, characterized by comprising: