JPS5836642B2 - Electrical sintering equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method of obtaining a molded product by sintering a powder raw material by applying current under pressure or applying current accompanied by minute discharge, etc. Public bulletin, 45
The present invention relates to an electric sintering apparatus as described in Japanese Patent No. 32328.

This electrification sintering (including discharge sintering) is widely used, but when trying to obtain dog-shaped products using this method, not only a large-capacity power source is required, but also raw materials are consumed due to energization heating. There was also the problem that the resistance value of the molding die changed in a direction undesirable for molding, making it difficult to uniformly heat and bake the entire raw material.

Further, it has been impossible to sinter the partial carbon so that the density, sintering state, etc. are different as desired.

The present invention has been made based on the above-mentioned viewpoint, and its object is to use a relatively small-capacity power source to perform firing uniformly or partially with six different degrees of difference as desired. An object of the present invention is to provide an electrical sintering device capable of producing large-sized molded products.

The gist thereof is that the mold has a mold for prescribing, and a plurality of processing punches and/or anvils that are divided into a plurality of parts and electrically insulated from each other,
When the powder raw material is filled and compressed into the closed space formed by the processing punch and anvil, the powder is compressed through the divided processing punch and anvil parts independently from the other divided parts. In the energizing sintering apparatus O, which energizes the raw material to process it and obtain a sintered or shaped product, the energizing power source for sintering, the power source, and the dividing punches and/or The present invention is to provide an energization circuit connected to each anvil via a control switch, and an energization control device for switching and controlling the plurality of control switches.

Hereinafter, details of the present invention will be explained with reference to the drawings.

Fig. 1 is a model diagram showing one embodiment of the current sintering device of the present invention C, Fig. 2 is a detailed diagram of a punch used in the device, and Fig. 3 is a model showing another embodiment. It is a diagram.

The explanation will be given sequentially starting from FIG.

In Fig. 1, 1 is a mold made of carbon, metal, alloy, etc. suitable for obtaining circular, rectangular, or irregular plate-shaped articles, 2 is an anvil, 3 is a support shaft that can be raised and lowered, and 4-1 4-3 are pressure punches, 5-1 to 5-3 are punches 4-1, respectively.
to 4-3, and is raised and lowered by a hydraulic device 6 (not shown); 6 is a powdered metal material; 7 is a sintering power source; 8 is a power switch; 9 is a girder element 9- ring counter with 1 to 9-3, 10
-1 to 10-3 are the ring counters 9, respectively.
A switching element 11 corresponding to the digit elements 9-1 to 9-3 and made conductive by its output is a timing pulse oscillator.

As illustrated in FIG. 2, the punches 4-1 to 4-3 each have a main body 4-1a made of metal or graphite coated with an insulating member 4-1b on the side surface. In the state shown in FIG. 1, they are insulated from each other (on this side).

The metal material 6 is held between the anvil 2 and the punches 4-1 to 4-3 inside the mold 1, and is applied to a desired pressure or a predetermined pressure by servo control by a force supplied from an independent hydraulic device (not shown). is pressurized.

On the other hand, the timing pulse oscillator 11 oscillates timing pulses at a desired cycle or according to a sequence or other control program to drive the ring counter 9.

The outputs of each digit element 9-1 to 9-3 of the ring counter 9 are supplied to switching elements 10-1 to 10-3, respectively, and therefore, these switching elements 10-1 to 10-3 are rotated. becomes electrically conductive.

When the switch 8 is turned on in this state, the metal material 6 is energized via the switching element in the conductive state and the corresponding punch.

As shown, digit element 9 of ring counter 9
When -1 is 1, the above-mentioned energization is performed via the switching element 10-1, the stem 5-1, and the punch 4-1, and about one-third of the left side of the metal material 6 is energized and heated. Ru.

Next, when the ring count 9 operates and the 1 display position moves to the girder elements 9-2 and 9-3, about one-third of the center and about one-third of the right side of the metal material 6 are energized and heated, respectively. As a result, energization is repeated in accordance with the same cycle or control program G until the switch 8 is turned off, and the metal material 6 is sintered.

In this case, the parts close to the mold 1, that is, the left and right (/
) When performing current sintering on either end, when sintering the central part (the leakage current flowing through the mold 1 tends to increase, take this into account) It is desirable to determine the effective cross-sectional area and pressing force of the punch and take precautions to ensure uniform sintering.

In addition, for homogeneous sintering or partially different heterogeneous sintering, we need a control circuit that can rationally control the energization time, number of energizations, etc. for each punch. It is natural to use .

At that time, pressurizing punch 4-1 for each part. 4-
2. Servo pressurization by 4-3, arbitrary pressurization, molding pressurization, etc. are also controlled in combination at the same time.

Next, FIG. 3 will be explained.

In the figure, 21 is a mold suitable for obtaining a disk-shaped molded product, 22
23 is a main anvil, 23 is a column that can be raised and lowered, 24 is a punch, 25 is a pressurizing stem, 26 is a powdered metal material, 27
-1 to 27-3 are disc-shaped or annular current-carrying anvils, 28 is an insulating member, 29 is a three-phase half-wave rectifier circuit, 30-1
30-3 are diodes forming part of the rectifier circuit 29.

The metal material 26 is placed inside the mold 21 by an energizing anvil 27-
1 to 27-3 and the punch 24 and are pressurized.

When Sanwa alternating current is supplied to the rectifier circuit 29 in this state, the diodes 30-1 to 30-3 are sequentially turned on one by one, and power is sequentially supplied to the anvils 27-1 to 27-3. .

Since the rectifier circuit 29 is a three-phase half-wave rectifier circuit, the above-mentioned energization is always performed through only one diode, and energization is performed simultaneously through two or more diodes. There is no.

That is, in this case, the Sanwa power supply circuit itself also serves as the energization control circuit.

Therefore, the current is applied to, for example, the central part of the metal material 6, the outer peripheral part,
The sintering is carried out in rotation in the order of the outermost periphery, and the energized area in each case is selected so as to achieve uniform sintering, so that uniform sintering is achieved.

The present invention is configured as described above, and according to the present invention, sintering can be performed partially and rationally, so a relatively small capacity power source is sufficient, and homogeneous or partial
This allows sintering to occur with desired non-uniformity.

It should be noted that the configuration of the present invention is not limited to the above-mentioned embodiments, and the method and number of divisions of the punch and anvil can be freely changed, and they may also be divided into two parts.
If you are trying to obtain a molded product with partially different wall thicknesses or a molded product with a shape that has a large leakage current through the mold and is difficult to sinter uniformly, use a more advanced energization method to improve the uniformity of sintering. Uses a control circuit to appropriately distribute current,
The present invention encompasses all of them.

That is, in the above-mentioned embodiments and explanations, not only the energization switching is carried out in single G rotation or sequential switching, but also the energization switching order, period, Switching control of energization by economically changing the duration of energization, etc., or
Although it is possible to control the voltage, current, ratio of AC/DC components of this power supply, frequency of AC components, and the pressurization state of each pressurizing punch, it is also possible to control the temperature and shrinkage of the metal material 6 of the part corresponding to each pressurizing punch. Detectors that detect each situation separately, and detectors that detect resistance, voltage, etc. between each punch and anvil are installed, and from this point the energization can be controlled or the firing process can be performed while modifying a pre-made program. It is also possible to continue the connection.

[Brief explanation of the drawing]

FIG. 1 is a model diagram showing an actual case of the current sintering apparatus according to the present invention, FIG. 2 is a detailed view of the punch, and FIG. 3 is a model diagram showing another embodiment. 1,21...type, 2,22.27-1,272
．． 27-3...Anvil, 4-1. 4-2
．． 4-3. 24... Punch, 6, 26.
...Powdered metal material.

Claims (1)

[Scope of Claims] 1. It has a mold for forming, and a plurality of processing punches and/or anvils that are divided into a plurality of parts and are electrically insulated from each other, The sealed space formed by the anvil (the powder raw material is filled and compressed, and the powder raw material is energized through the divided processing punch and anvil parts, independently of the other divided parts). In the energizing sintering device for processing and obtaining sintered shaped products, the energizing power source for sintering, the power source is controlled by each of the divided punches and/or anvil G which are electrically insulated from each other. The above-mentioned energization sintering apparatus is provided with an energization circuit connected via a switch, and an energization control device for switching and controlling the plurality of control switches.