JPH0783954B2 - Powder molding method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a powder molding method for forming a stepped powder compact.

(Prior Art) Generally, in the molding of stepped powder compact,
The molding apparatus found in the 096 publication is used.

As shown in FIG. 8, this type of device includes a lower die 100 that is movable up and down, a fixed punch 104 that is fixed to a base plate 102, and a floating punch 108 that is fixed to a floating holder 106. The fixed punch 104 and the floating punch 108 are provided with the lower die.
It is arranged on the lower end side of the molding part in 100 to form a powder filling cavity.

That is, the powder filling cavity 110 formed by the lower die 100, the fixed punch 104, and the floating punch 108 is filled with the powder by the powder filling shoe 110 that covers the upper end of the lower die. The powder in the powder filling cavity 116 is pressed by the upper punch to form a stepped powder compact. In order to take out the stepped powder compact 112 formed in this manner, the lower die 100 is moved downward to move the fixed punch 10 as shown in FIG.
4, the upper die of the floating punch 108 is the lower die 100
The stepped powder compact 112 is ejected from the inside of the molding part of the lower die 100 to project from the upper end surface thereof. On the other hand, as shown in FIG. 8 (III), the powder filling shoe 110 is slid on the upper surface of the lower die 100 to cover the molding portion of the lower die 100 in the step of raising the lower die 100. It is supposed to be installed.

(Problems to be Solved by the Invention) By the way, the floating punch 108 is biased upward by the spring 114 arranged between the base plate 102 and the floating holder 106, and therefore the lower die 100 is lifted. At the beginning of the stroke, the floating punch 108 follows the upward movement of the lower die 100 (see FIG. 8 (II)).

Therefore, in the powder molding method using this kind of apparatus, the upper end surface of the floating punch 108 and the lower die 100
It was supposed that the powder filling shoe 110 should be operated for the first time after waiting for the state where the upper end surface of the powder filling surface is flush with the upper surface of the
See I)). Of course, at this stage, the powder filling cavity 11 is placed between the floating punch 108 and the fixed punch 106.
Therefore, according to the conventional method, the powder filling process is started from the state where the powder filling cavity 116 is formed to some extent.

However, when the powder is filled from the state where the powder filling cavity is formed to some extent, it is inevitable in terms of filling accuracy.

Therefore, it is an object of the present invention to provide a powder molding method in which the powder is filled from the initial stage of forming the powder filling cavity.

(Means and Actions for Solving Problems) In the present invention, when obtaining a stepped powder compact using the above-mentioned device, the lower die is set at the beginning of the ascending stroke of the lower die,
The upper ends of the fixed punch and the floating punch are flush with each other, and the flush state operates the powder filling shoe.

Specifically, a powder filling cavity is formed in the molding part by a fixed punch and a floating punch disposed on the lower end surface of the molding part of the lower die, and the powder is filled by a powder filling shoe that covers the upper end of the lower die. Assuming a powder molding apparatus configured to mold a stepped powder compact by pressing the powder filled in the filling cavity with the upper punch, the rough die, fixed punch, and floating punch Forming a flush state where the top surface is flush,
In the flush state, the powder filling shoe is operated to form the powder filling cavity, and the powder is filled in the powder filling cavity.

By doing so, the powder charged from the powder filling shoe is suction-filled by the suction force accompanying the formation of the powder-filling cavity.

(Example) Hereinafter, the Example of this invention is described based on a figure.

FIG. 1 shows a molding machine applied to the embodiment. The molding machine has respective elements symmetrically arranged. The cross-sectional position is changed and shown in figure.

In FIG. 1, the molding machine 1 includes a base plate 2 and a yoke plate 4 disposed below the base plate 2, while a lower die plate 6 is disposed above the base plate 2. The plate 6 is integrated with the connecting rod 8. Lower die plate 6
On the other hand, a lower die 9 is attached to the lower die, and a core rod 10 is erected on the yoke plate 4. The core rod 10 penetrates the base plate 2 and its upper end extends into the lower die 9. Has been done.

A fixed punch 12 and a floating punch 14 are arranged in this order from the core rod 10 in order to form a powder filling cavity A in the lower end die 9. The fixed punch 12 is erected on the base plate 2 while the floating punch 14 is It is erected on the floating holder 16. The floating holder 16 is disposed in a space sandwiched between the base plate 2 and the lower die 9, and the height adjustment of the floating holder 16, that is, the distance between the floating holder 16 and the base plate 2 is adjusted by an adjusting shaft penetrating the base plate 2.
It is designed to be carried out by a nut 20 screwed to 18. The floating holder 16 is floatingly supported by a spring 22 arranged between the floating holder 16 and the base plate 2. When pressure molding is performed by the upper punch 24, the floating holder 16 is received by a block 26 arranged on the base plate 2. It is supposed to be done. The block 26 is movable along the upper surface of the base plate 2, and the above-mentioned retreat operation is performed in the stepped powder compact removal process described below.

Further, the floating holder 16 has an ejection rod 28 fixedly mounted on the upper surface thereof, and the height of the ejection rod 28 is
The height dimension of the floating punch 14 is such that the upper end of the floating punch 14 slightly projects from the upper end surface of the lower die 9. Up to this point, the process is the same as the conventional one, so further description is omitted.

In the molding machine 1, in the present embodiment, the second spring 30 is arranged on the floating holder 16 coaxially with the ejection rod 28, while the third spring 32 is arranged on the base plate 2. It is arranged.

The second spring 30 has a larger spring force than the spring 22 that supports the floating holder 16 in a floating manner, while the third spring 32 is sufficient to regulate the lower limit stroke end of the floating holder 16. The third spring 32 is assumed to have a spring force, and functions as a stopper for the floating holder 16.

A method of forming a stepped pressure-formed body using such a molding machine 1 will be described below with reference to FIGS. 2 to 7.

First, as shown in FIG. 2, when the powder filling into the powder filling cavity A by the powder filling shoe 34 is completed, the powder filling shoe 34 is withdrawn and the upper punch 24 applies pressure (FIG. 3). . The takeout of the stepped green compact B molded in this way is moved to the block 26, and then, by the operation of the drive source (not shown) linked with the yoke plate 4,
This is performed by lowering the yoke plate 4, that is, lowering the lower die 9 (see FIG. 4). At the lower stroke end of the lower die 9, the floating holder
As a result of 16 being received by the third spring 32, as shown in FIG. 5, the upper end of the floating punch 14 protrudes from the upper end surface of the lower die 9 by a dimension H, whereby a stepped powder compact is formed. B is released from inside the lower die 9.

FIG. 6 shows an initial state in which the lower die 9 has started to move upward. At the initial stage of this ascending movement, the floating holder 16 is held in the state shown in FIG. 5 by the spring force of the second spring 30. That is, the floating punch 14 is maintained as it is without following the upward movement of the lower die 9, and as a result, the lower die 9 is held.
The upper die of the lower die 9, the fixed punch 12, and the floating punch 14 is flush with each other in accordance with the ascending movement of. Then, the powder filling shoe 34 is moved to a predetermined position in synchronism with the formation of the flush condition, and the step compacted powder compact B is removed by the push 36 attached to the powder filling shoe 34, while the powder is pressed. The operation of the filling shoe 34 is started.

Therefore, the powder is filled under the suction force that accompanies the increase in the volume of the powder filling cavity A from the initial formation of the powder filling cavity A formed by the subsequent upward movement of the lower die 9.

(Effects of the Invention) As is clear from the above description, according to the present invention, the powder filling into the powder filling cavity is performed from the initial stage of forming the cavity under suction filling, thus improving the powder filling accuracy. be able to.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a molding machine used for carrying out the present invention, FIGS. 2 to 7 are process explanatory diagrams showing each process in an embodiment, and FIG. 8 shows a conventional example, and FIG. (I) is an explanatory diagram showing a stepped powder compact discharged state, FIG. 8 (II) is an initial state of starting lower die die start, and FIG. 8 (III) is an explanatory diagram showing a movement starting state of the powder filling shoe. 1: Molding machine 2: Base plate 4: Yoke plate 9: Lower die 12: Fixed punch 14: Floating punch 16: Floating holder 22: Spring 24: Upper punch 28: Ejection rod 30: Second spring 32: Third Spring 34: Powder filling shoe 36: Pusher A: Powder molding cavity B: Stepped powder compact

Claims (1)

[Claims] 1. A powder-filling cavity is formed in the molding part by a fixed punch and a floating punch arranged on the lower end surface of the molding part of the lower die, and a powder-filling shoe covering the upper end of the lower die is used to form the powder-filling cavity. In a powder molding apparatus configured to mold a step-compacted powder compact by pressing the powder filled in the powder filling cavity with an upper punch, the lower die, the fixed punch, and the floating punch An end face is formed into a flush state, and in the flush state, the powder filling shoe is operated to form the powder filling cavity and fill the powder into the powder filling cavity. A powder molding method characterized by the above.