JPH01205002A - Sintering apparatus by conducting electricity - Google Patents

Abstract

PURPOSE:To rapidly sintered-compact powder for sintering into high density and to easily obtain a sintered body having good quality for short time by packing the powder for sintering into a die, sintering by conducting electricity the powder for sintering in the die while pressurize-pressing with punches and also heating the punch and/or the die by conducting the electricity. CONSTITUTION:The powder 2 for sintering is packed in the die 1 and by working the pressurizing cylinders 8, 9, it is pressurize-pressed with the punches 3, 4. Further, by conducting the electricity from a power source 5 for sintering to the powder 2 for sintering in the die through the punches 3, 4. In the above sintering apparatus by conducting the electricity, the punches 3, 4 are divided with insulating materials 3a, 4a, respectively and connected to the power sources 6, 7 for heating. This heating device may be arranged to the die 1. By these heating devices, the punches 3, 4 and if necessary, the die 1 are beforehand heated the prescribed temp. before pressurize-sintering. By this method, the starting characteristics of heating control for the powder 2 in the die and control for powder density at the time of pressurize-pressing is improved and the sintering is efficiently executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electric current sintering apparatus for sintering powder by electric current.

[Prior art and issues]

Conventional energizing sintering apparatuses are only equipped with an energizing power source for sintering, which energizes the powder. In this case, heat dissipates to the punch, etc., so the rise characteristics of powder heating during sintering are poor, it takes a long time to increase the powder density, and depending on the material of the sintered powder, there may be deterioration, resulting in good sintering. I couldn't do it.

In particular, when sintering ceramics or other high-resistance materials into powder, a large current does not flow at first, and the rise of the heating temperature is delayed, and uniform sintering is difficult when the sintered body has a complex shape.

In addition, high-density sintering required high-pressure punching of more than a ton/cm2, but
Even so, it was not easy to discharge the interpowder gas.

(Means for solving Problem J) The present invention was invented to improve the above-mentioned conventional drawbacks, and includes the provision of a heating power source that heats two parts of the die or punch by energizing them, and the vibration of the die or punch. The present invention is characterized in that it is provided with a photographing device that allows

[Example of fruit eggplant]

The present invention will be explained below with reference to an embodiment of the drawings.

In FIG. 1, numeral 1 denotes a mold having a desired shape, into which sintering powder 2 is filled and sintered. Pressure punches 3 and 4 are inserted from the top and bottom of the mold 1, and serve also as current-carrying electrodes to connect the sintering current-carrying power source 5. Each punch 3.4 is provided with a groove in the length direction or with insulators 3a, 4a interposed therebetween;
A heating power source 6 that straddles both insulated ends and heats by energizing it.
, 7 are connected. Further, the mold 1 can also be heated by connecting a heating power source that heats the mold 1 by applying electricity from the upper and lower ends thereof.

8 and 9 are cylinders that drive the pressure punch 3.4, and these power supplies 5, 6.7 and cylinders 8, 9 are program-controlled by the NC control device 10.

Pressure is applied to the pressure punches 3 and 4 by the pressure device of the pressure cylinder 8.9, and the powder 2 in the mold 1 is energized by the controlled pressure press and the sintering energizing power source 5, and the powder is The material is sintered by generating discharge heat, Joule heat, etc. For energization, it is preferable to apply a pulsed alternating current that is likely to cause a powder discharge, and when the energization becomes good due to heating, control is performed such that a direct current component is energized.

Therefore, each of the punches 3.4 is connected to a heating mold FA67, so that the punches themselves can be heated to an appropriate temperature before sintering, and the optimum temperature can be achieved by program control of the NC device 10. Perform heating. The master mold 1 is also provided with a heating power source so that it can be heated in advance. Each heating temperature can be programmed and controlled according to conditions such as the type of sintered powder and sintered density. For example, if the sintering temperature depending on the material is about 400°C, the punch etc. should be heated to about 200°C in advance. By pressurizing the powder 2 using the heated bumps 3.4, the rise characteristics of the heating control and powder density control of the powder 2 in the mold can be improved, and rapid sintering can be performed.

FIG. 2 is a characteristic diagram showing the temporal change in the sintered powder density ρ during predetermined heating and pressurization during powder sintering, which shows a rapid rise in the sintered powder density ρ when compared to the conventional one. It is possible to increase the density to a predetermined level in about 10 to 20 seconds from the start of sintering.

FIG. 3 shows an embodiment in which a vibrating device 11 is provided in addition to a pressurizing device (not shown) on both the upper and lower pressurizing punches 3, 4, or one of the pressurizing punches 3, 4, so that vibrations are applied in a superimposed manner during pressurization.

By applying vibration pressure, the sintered powder in the mold is heated while causing powder flow between them, so the powder filling effect is enhanced and high density can be controlled in a short time. It is possible to perform high-density packing and sintering with reduced press pressure. For example, when sintering 600 meshes of iron powder to a density of 98%, the imaging width is approximately 0.5 mm,
When vibrations with a frequency of 50) 1z are superimposed on the pressing punch, the pressure that would have required 2 tons/cm2 without vibration can be sintered at approximately 0.5 tons/C112. It was confirmed that the high density packing effect was high. The working vibration usually has a frequency of 10-100Hz and an amplitude of 0.25-
Use approximately 2 mm.

(Effects of the Invention) As described above, in powder sintering, the present invention is provided with a heating power source that heats the mold or punch by passing current between at least two places. Alternatively, the punch can be heated in advance, and the powder can be sintered by pressurizing and pressing with this heating die or heating punch, and the powder can be energized and heated rapidly during sintering, resulting in rapid sintering and forming with high density. This makes it possible to easily form a high-quality sintered body through powder sintering by energizing in a very short time. In particular, if the sintered powder is made of ceramics or a high-resistance material, the current cannot be increased even if pulses or shock waves are first applied.
The heating punch can lower the heating resistance from the contact area in a rolling manner, allowing a large current to flow in a short period of time, and sintering with rapid energization and heating start-up characteristics. Also, during this sintering, by applying pressure and vibration to the pressurizing punch, the fluidity of the filled powder is increased, and impurities such as gas and bubbles generated by energized heating are better discharged, resulting in a rapid increase in the energizing current. The powder filling rate can be easily increased, and a predetermined high-density sintering can be performed in a short time with a reduced press force.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention, FIG. 2 is an explanatory diagram of sintering characteristics, and FIG. 3 is a partial block diagram of another embodiment. 1...Mold 2...Powder 3.4...Punch 5... ...Sintering energizing power supply 6.7...
・・・・・・Heating power source 8.9・・・・・・Pressure cylinder 10・・・・・・
.......NC control device 11....
... Vibration device properties Applicant: Kiyoshi Inoue, Representative of Inoue Japax Laboratory Co., Ltd. Figure 2 10-20 hours sec Figure 3

Claims (2)

[Claims] (1) Electrical sintering that includes a mold filled with sintered powder, a punch that presses and presses the powder filled in the mold, and a sintering power source that sinters the powder filled in the mold with electricity through the punch. An electrical sintering apparatus characterized in that a heating power source is provided for heating the die or punch by passing current between at least two locations thereof. (2) An energizing sintering device equipped with a mold filled with sintered powder, a punch that presses and presses the powder filled in the mold, and a sintering power source that sinters the powder filled in the mold with electricity through the punch. An electric sintering apparatus characterized in that it is provided with a heating power source that heats the mold or punch by passing current between at least two locations thereof, and a vibration device that vibrates the mold or punch.