JPS5814843B2 - powder sintering equipment - Google Patents

Description

[Detailed description of the invention] The present invention applies pressure and electricity to the sintered powder that has been placed in a mold,
This invention relates to a sintering device that generates electrical discharge and Joule heat between powders to sinter and sinter them.

In discharge sintering, the powder in a predetermined mold filled with any powder to be sintered is lightly pressurized using at least one of the current-carrying electrodes as a pressurizer and energized to cause inter-powder discharge and sintering. Devices or methods have been proposed and already implemented.

Even with this discharge sintering, it is difficult to obtain a homogeneous sintered product depending on the shape of the mold, the properties of the powder, the way the electrodes are used, etc., and it is often difficult to reduce the power consumption.

In view of the above-mentioned drawbacks of the conventional technology, a method with low power consumption,
It is an object of the present invention to provide a sintering apparatus that can easily produce a sintered body having a desired density and a desired degree of homogeneity.

The characteristics of the present invention are that X, -X, Y, -Y, Z, -Z
A pressure punch that can be pressurized, molded, and energized from six sides or at least two directions is used by dividing it into an arbitrary number of pieces.

In addition, the pressurizing force can be arbitrarily changed for each divided punch, the energization can be changed for each divided electrode, and the sintering pressure and energization can be arbitrarily applied to each divided punch or each electrode separately or at the same time. .

Further, by controlling an arbitrary time delay by a program, each division section or all sections are energized and sintered at the same time.

Further, the sintered powder can be applied as a solid, kneaded together, or in the form of a film, and different types of powders can also be mixed or laminated in layers.

Next, the present invention will be explained based on examples.

FIG. 1 is a front view showing one embodiment of the present invention.

When the particle size of the sintered powder becomes large, uniformity cannot be obtained, resulting in uneven suppression and energization.

In particular, if non-uniformity is desired, the particle size of the sintered powder is preferably small.

It is also preferable that the particle size is uniform. Usually less than 1 mm is used.

In this way, the fine powders are mixed evenly and used, but if you expect to generate an interpowder discharge when energized, consider the uniformity of the particles, the filling method, the dimensions and shape of the sintered product, the size, and the pressurizing conditions. and select.

The pressure during sintering can be lightened, and electric current can be applied to generate inter-powder discharge, resulting in ionization, ion diffusion, and
The material is selected in such a way that it generates Joule heat in a very short time, and as a result, a uniform sintered product can be obtained with low electric power.

As shown in FIG. 1, the powder to be sintered 17 is filled into the formwork 14, and cylinders A1 to A4, B1 to B4 are filled from the top, bottom, left and right.
, C, and D for sintering.

The formwork 14 is heat resistant and flexible. In FIG. 1, a pressure punch 12 is used, which is divided into four upper and lower parts, each forming a pair of upper and lower parts.

Each punch is connected to a cylinder, and each stroke of the cylinder can be changed to change the pressing force.

Each cylinder AI, A2, A3, A4, Bl, B
2, B3, B4 The valves P1, P2, P3, P4, P5, P6, P7 are set by the rotary set changeover switch 8.
Working fluid is supplied from the pump 9 and controlled by the control of P8.

The rotary set changeover switch 8 includes a movable contact piece 7 that rotates around a central point 6, and fixed contacts A1, A2 arranged radially.
Consists of A3, A4, B1, B2, B3, B4,
Contacts A, , B1, A2, B are selected by rotating the movable contact piece 7.
2, A3, B3, A4, B4 are switched simultaneously, and the valves P1, P5, P2 t P6, P3, P7 respectively
It operates so that t P4 and P8 are switched.

18 is a valve control power source. By selecting the changeover switch 8 as described above, the cylinders are A1, B1, and A1.
2 and B2, A3 and B3, A4 and B4 are controlled simultaneously,
The opposing splitting punches 12 are actuated to partially pressurize the mixed powder 17 in the formwork 14 and sinter it with electricity, and this sintering process is performed sequentially until the entire powder 17 in the formwork 14 is sintered. will be carried out.

Although the sintering power source is not shown, each punch 12 is dividedly energized in parallel, and the pressurized portion is energized, and pulses, DC + A sintering power source such as an alternating current is applied, an induced current is applied by an induction coil, and a combination of these is applied.

The separate pressing molds 12 of the cylinder units A1 and B1 are placed in the formwork 1.
4, the mixed powder 17 is pressed, the pressing force is controlled, and electricity is applied.

Electricity is applied to generate a discharge between grains, decompose and remove intergranular oxides, gases, etc., activate the powder, ionize it, diffuse the ions, and generate Joule heat, resulting in sintering.

Now, powder with a particle size of 100 microns to 2 mm in diameter is initially mixed at 1 kg/cm2. Apply a pressing force of 2 to 4
Power on for seconds.

Next, each predetermined cylinder unit is energized for a predetermined time under pressure control with a delay of a predetermined time or at the same time.

Next 1. A pressing force of Okg/cr# is applied, and pressure is energized with a time delay for each cylinder unit.

During these energizations, a pressing force of 1 to 10 kg/i is similarly applied by the side cylinder units l-C, T).

In other embodiments, 5 kq/cr? 7. I went in one step.
For each opposing cylinder block with a predetermined delay time,
Furthermore, as a result of program-controlled pressing and energization of these cylinder units, a homogeneous sintered product was obtained with low power consumption.

Note that if the mold frame 14 obstructs the current flow when electricity is applied from each divided punch 12, the mold of the punch 12 portion is removed so that the tip of the punch directly contacts the powder 17 to allow electricity to flow.

The tip of the punch is provided with a heat-resistant material. A high-frequency current coil may be provided outside the mold to heat the sintered powder by causing an induced current between the grains in addition to the above-mentioned energization, and the effect is further improved by superimposing the above-mentioned direct energization and this induced current. did.

In the example in which the mold was divided into 10 parts, the required power was only 16 to 20% compared to the case where the same energization was carried out in the entire mold without dividing the powder.

Now, program control is as illustrated in Figure 5.
The hydraulic systems, pump unit P, and hydraulic piping 0 of cylinders A1, A2, and A3 are connected to a program unit NC, and the control valves P1, P2, and P3 shown in the figure are opened and closed according to the program, and the pressing force is changed, and the discharge In parallel.

Even better results can be obtained in programming when three axes, X, Y, and Z, or at least two axes, are incorporated.

Next, FIG. 2 will be explained.

A plan sectional view is shown. In the case of Figure 1, the center,
This corresponds to a cross section that crosses C, D, 12, and 17.

As shown in the figure, the mold 14 has a structure in which the center width is narrowed, and the punch is 1M or 2M depending on the sintered shape.
Divide into M, 3M, 4M, 5M, 1M and 5M, 2M and 4
M are each isomorphic.

The powder is transferred to cylinder units E1, E1 and E1 in the formwork 14.
IM, 2M, 3M, 4M are pressed with the punch 12 by E2, E3, and E4 in the same manner as explained in FIG.
, 5M and the punch 12 are molded under program control.

The splitting effect was significantly better.

Next, FIG. 3 will be explained.

Without using a hydraulic cylinder, each divided punch 12 is a screw-type pressurizing device Fl, F2, .
. . . groups 10B are provided, each of which is driven using a drive unit 10A to drive the rod 11 to move each divided type.

The drive unit 10A can perform precise pressure control by controlling it using a pulse motor.

It can be operated and program controlled in the same manner as in FIG.

Next, FIG. 4 corresponds, for example, to a plan view of a cross section taken along the line XX in FIG. 3.

For the mold 14 filled with powder, we used a split mold divided into 8 equal parts, and the horizontal mold was also divided into suitable areas of K3 and K4.
Sintering is performed under program control in the same manner as shown in FIGS.

In the case of Fig. 4, as shown in Fig. 3,
, -Y, Z, and -Z.

In the case of FIG. 1, although it is called 3-axis control, it is more like 2-axis control.

In the case of Fig. 4, the press and energization of the molds 12 of K1, K2, K3, and K4 are used to almost the same extent without distinguishing between the divided molds 15 and 12, and program control is performed with an appropriate time delay set. went.

When pressurization was controlled from multiple directions and by means of divided punches in this way, the power consumption was 8 to 10% compared to the case of using a full-form type, which was an extremely significant labor-saving effect.

Furthermore, the sintered products with better labor-saving effects were more homogeneous.

In addition, by partially sintering the divided parts, it is possible to uniformly sinter a large product with less power consumption, and by controlling the pressure applied alternately or sequentially from at least two directions using a dividing punch, the filling powder 17 in the formwork 14 can be sintered uniformly. A powder kneading effect can also be expected during the electric discharge and Joule heating treatment, and as a result, a homogeneous and high quality sintered body can be obtained.

Furthermore, instead of the sintering powder, use the powder to be sintered that is as small and uniform in particle size as possible, and mix well by kneading it with a glue or chemical substance that will not leave a residue after sintering. Then, the kneaded product was made into a film, the same kind of powder or different kinds of powder were laminated separately as films, and as explained in Figs. Similar to the above description, a highly homogeneous sintered product was obtained with very efficient power savings.

As already mentioned, a powder or a film-like mixture of powder and an adhesive, or a combination thereof, is pressed and energized from at least two sides using a dividing punch, and divided into individual pieces. The pressurizing operation is controlled simultaneously for all the divided parts or separately for each predetermined divided part at a delay time, and the pressing strength of the punch of each divided part is controlled, and the punch is pressurized and energized. A sintered product was obtained by controlling the program to generate an interpowder discharge, and in some cases, a high-frequency current coil was installed on the outer periphery to generate an induced current between the powders.

With this device, it was possible to obtain extremely uniform sintered products, as well as products with complex shapes, and the power consumption was able to be extremely reduced.

It requires 8-20% less power than conventional devices.

In addition, irregularly shaped products can be obtained as good homogeneous products.
What was thought to be impossible with conventional equipment,
It was easy to manufacture.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front sectional view of one embodiment of the present invention, and FIG. 2 is a partial plan sectional view. FIG. 3 is a front sectional view of one application example. FIG. 4 is a partial plan cross-sectional view. FIG. 5 is an explanatory diagram showing one example of program control. AI, A2, A3, A4, B1, B2, B3, 1B4
, C, D, E1, E2, E3, E4, K1, K2, K3
, K4: Cylinder unit, F1, F2, F3, F4,
G1, G2, G3, G4, H1, J: Screw unit, X, Y, Z: Each of the 3 axes, 1M, 2M, 3M, 4
M, 5M, 12, 15: division punch, 10: cylinder,
8: Rotary changeover switch, 9: Hydraulic pump, 18:
Power supply, 10A: Drive mechanism, 10B: Screw, 11:
Rod, P: Pump unit, P,, P2, P3, P4
, P5, P6, P7, P8: Valve unit, 01, 02,
03: Piping, NC: Program control unit.

Claims (1)

[Scope of Claims] 1. In a sintering device that simultaneously controls pressure and energization of powder in a predetermined mold filled with powder to be sintered, an arbitrary number of punches for pressurizing the powder are provided. The punch is divided into two parts and provided in at least two directions, and each divided part of the punch is provided with a pressurizing device that can control the change in pressure strength, and all the divided parts are applied simultaneously or for each predetermined divided part. 1. A powder sintering apparatus characterized in that a control device is provided to separately control the pressurizing operation with a time difference and to control the pressurizing strength of each divided punch. 2. The control device that controls the pressurizing operation of all the divided sections simultaneously or separately with a time difference for each predetermined divided section and controls the pressing strength of the punch of each divided section is characterized by using a program control device. A powder sintering apparatus according to claim 1. 3. The powder sintering apparatus according to claim 1 or 2, wherein the pressure punches are divided into numbers and sizes depending on the sintering shape and size. 4 For energization, use a pressure punch as an electrode to energize;
Alternatively, the powder sintering apparatus according to claim 1, 2, or 3, which is also capable of generating an induced current between the powders to conduct electricity. 5 The sintering pressure is controlled at 0.5 to 10 kg/cm2, and electricity is applied between the opposing split molds through a pressure punch under pressure control, and a high-frequency current coil is installed around the mold to control the powder. The powder sintering apparatus according to claim 1, 2, 3, or 4, in which a mechanism capable of generating an induced current is used in combination.