JP3217121B2 - Manufacturing method of sintered body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a composite structure sintered body.

[0002]

2. Description of the Related Art Injection molding is known as one method of processing metal powder or ceramic powder into a predetermined shape. JP-A-59-229403 describes a conventional method for producing such metal powder and ceramic powder. In this method, a metal powder or a ceramic powder and an organic binder are kneaded, the mixture is injection-molded into a predetermined shape, and then degreased and sintered to obtain a product.

[0003]

However, in the conventional method, a single product is molded, and in order to produce a composite in which a plurality of products are combined, it is necessary to assemble the molded products. For this reason, an assembling process was required, and the number of processes increased, resulting in a decrease in production efficiency. In particular, in the case of a small product, it is difficult to assemble, which has been a major problem in manufacturing.

The present invention has been made in view of the above circumstances, and has as its object to provide a manufacturing method capable of manufacturing a sintered body having a composite structure without requiring assembly.

[0005]

In order to achieve the above object, a production method of the present invention comprises a step of injection molding a mixture of a metal powder or a ceramic powder and an organic binder to form a primary molded body, and forming the primary molded body. After oxidizing or nitriding the surface of the body, a mixture of a metal powder or a ceramic powder and an organic binder is injection-molded so as to be connected to the primary molded body, and then degreased and sintered. is there. Further, another manufacturing method of the present invention, after oxidizing or nitriding the surface of a component made of metal or ceramics, injection molding a mixture of a metal powder or ceramics powder and an organic binder to connect with the component, and then , Degreasing and sintering.

[0006]

By oxidizing or nitriding the surface of the primary compact or the component, the powder of the secondary compact injected later is not welded during sintering. This is because the surface wettability is reduced by oxidizing or nitriding, and the fusion of the powder at the surface during sintering and the fusion of the powder due to the surface tension due to the surface melting do not occur. Thus, a sintered body in which the compacts are movably connected to each other can be manufactured without assembling.

[0007]

Embodiment 1 FIGS. 1 and 2 show a product having a composite structure manufactured according to Embodiment 1 of the present invention, which is used for a curved tube serving as a skeleton for freely bending the end of a scope of an endoscope. . This product 1 is composed of a first tube 2 and a second tube 3. First, after the first tube 2 is formed, the first tube 2 is formed.
The second tubular body 3 is formed so as to be connected to the second tubular body 3. The first tubular body 2 has a pair of flat portions 4 on the outer peripheral surface, and a boss 5 stands on one end of the flat portion 4. Second tube 3
Has an ear 6 extending in the direction of the plane portion 4 of the first tube 2, and the boss 5 of the first tube 2 is inserted into the ear 6. Thus, the tubes 2 and 3 can be bent vertically. In the following description, the molding of two parts, the first tubular body 2 and the second tubular body 3, will be described. However, as shown by a chain line in FIG. 2, a more continuous structure can be formed. .

FIG. 3 shows the entire structure of a molding apparatus used for manufacturing the present embodiment. This molding apparatus is configured by arranging two rigid injection molding machines 20 and 30 on the left and right sides of an arm member 10 that can move up and down and rotate. These first and second injection molding machines 20 and 30 are
1, 31 and fixed dies 22, 32 are opposed to each other, and movable dies 21, 31 are attached to movable platens 23, 33, while fixed dies 22, 32 are attached to fixed platens 24, 34. Also, cylinders 26, 36 having hoppers 25, 35 on the fixed platens 24, 34, respectively.
Are disposed in the cylinders 26 and 36, and screws 28 and 38, which are rotationally driven by motors 27 and 37, respectively.
Is inserted. A metal powder or a ceramic powder as a forming raw material is put into hoppers 25 and 35 in a state of being kneaded with an organic binder, and is introduced into cylinders 26 and 36 into cavities formed by fixed dies 22 and 32 and movable dies 21 and 31. Be injected.

FIG. 4 shows an arm member 10 in which a first motor 12 is mounted on a vertically movable support shaft 11, and a support 14 is orthogonal to a first rod 13 of the first motor 12. Installed. A second motor 15 is attached to one end of the support 14, and a rotation shaft 15 a of the second motor 15 passes through the support 14, and a second rod 15 is attached to a penetrating end of the rotation shaft 15 a. 16 are attached. The first motor 12 and the second motor 15 are provided with encoders for controlling the rotation thereof, and the second rod 16 is connected to the first motor 12.
As shown in FIG. 5, the motor rotates in a horizontal plane and rotates by driving the second motor 15.

In FIG. 3, reference numeral 40 denotes a blower disposed on the back side of the arm member 10, and 41 denotes a nozzle disposed together with the blower 40. These are provided such that their tips are located above the primary compact, the blower 40 is connected to a compressor 42, and the nozzle 41 is connected to a pump 43.
Is connected to the tank 44 via the In this case, an alcohol solution of sodium stearate is stored in the tank 44.

The movable molds 21 and 31 and the fixed mold 2 in the first injection molding machine 20 and the second injection molding machine 30 are used.
Numerals 2 and 32 form a molded body in a state in which the second rod 16 of the arm member 10 is included, and a primary molded body (see FIG. 2) is formed by the movable mold 21 and the fixed mold 22 of the first injection molding machine 20. 1 and the first tube 2) in FIG.
A secondary molded body (the second tubular body 3 in FIGS. 1 and 2) is molded by the movable mold 31 and the fixed mold 32 of the second injection molding machine 30.

FIGS. 6 and 7 are plan views of the fixed mold 22 and the movable mold 21 of the first injection molding machine 20 as viewed from the parting surface, respectively. As shown in FIG. 6, the fixed die 22 forms a cavity of the primary molded body between the semi-cylindrical surface portion 22 a fitted to the second rod 16 of the arm member 10 and the outer peripheral surface of the second rod 16. Outer peripheral forming surface portion 22b
And a flat portion 22c formed at the center of the outer peripheral forming surface portion 22b, and a gate 22d opened in the flat portion 22c.
And a concave portion 22e similarly formed in the flat portion 22c. The recess 22 e forms the boss 5 of the primary molded body 2. On the other hand, as shown in FIG. 7, the movable mold 21 includes a semi-cylindrical surface portion 21a, an outer peripheral forming surface portion 21b, a flat portion 22c, a concave portion 22e, and a gate 22d.
It is the same as the fixed type 22 except that there is no.

FIGS. 8 and 9 show a fixed mold 32 of the second injection molding machine 30, and FIG. 10 shows a movable mold 31 thereof. The fixed mold 32 is used for the second rod 16 of the arm member 10.
And a molded body fitting portion 3 fitted with a primary molded body formed on the outer peripheral surface of the second rod 16.
2b, a semi-ring shaped semi-ring zone 32c fixed so as to form a gap between one end of the primary molding to be fitted and the secondary molding, and the semi-ring zone 32c and the second semi-ring zone 32c. The outer peripheral surface 32d that forms the cavity of the secondary molded body with the outer peripheral surface of the rod 16 communicates with the molded body fitting portion 32b and the outer peripheral formed surface 32d to form the lug of the secondary molded body. It has a pair of ear forming recesses 32e and a gate 32f opened in the outer peripheral forming surface 32d. On the other hand, the movable mold 31 has the same configuration as the fixed mold 32 except that it does not have the gate 32f. As shown in FIG. 10, a semi-cylindrical surface portion 31a, a molded body fitting portion 31b, and a semi-ring zone 31c are provided. And the outer peripheral surface 3
1d and an ear forming recess 31c.

Next, a method for producing the sintered body shown in FIGS. 1 and 2 by the above-mentioned molding apparatus will be described. First, in the hoppers 25 and 35, 91 wt% of stainless steel (SUS316L) powder having an average particle size of 10 μm, 3 wt% of polystyrene, 3 wt% of acrylic, and 2 w of wax
A mixture with an organic binder consisting of t% and 1% by weight of stearic acid is charged. On the other hand, the movable mold 21 and the fixed mold 22 of the injection molding machine 20 are clamped so as to enclose the second rod 16, and the mixture is injected in a molten state from the cylinder 26, and is cooled and solidified to form the primary molded body 2. (Figure 1
And the first tube body 2) in FIG. 2 is formed. After this molding, the movable mold 21 is retracted, the mold is opened, the second rod is lowered, and the movable rod 21 is held in the state held by the rod 16.
The next molded body 2 is taken out. Then, the second rod 16
Turns 90 ° in the horizontal plane to form the primary compact 2 into the nozzle 41
Conveyed below. From this nozzle 41, an alcohol solution of sodium stearate is applied to the outer peripheral surface of the primary molded body 2,
In particular, it is sprayed near the boss 5. Further, oxygen is injected from the blower 40 to oxidize the surface of the primary molded body 2.

Thereafter, the second rod 16 is further moved to 90
And the primary molded body 2 is moved between the movable mold 31 and the fixed mold 32 of the second injection molding machine 30, and after this movement, the second motor 15 of the arm member 10 is driven. , The second rod 16 rotates by 90 °, whereby the primary molded body 2 rotates by 90 °. Then, the second rod 16 moves upward, the primary molded body 2 is mounted on the molded body fitting portion 32b of the fixed mold 32, and the movable mold 31 is clamped by the upward movement.
Thereafter, the mixture is injected into the cavities of the fixed mold 32 and the movable mold 31. Thereby, the semi-ring zones 32c, 31
c, the secondary compact 3 adjacent to the primary compact 2 (FIG. 1)
And the second tube 3) in FIG. 2 is formed (FIG. 5).
reference). The secondary molded body 3 is connected to the primary molded body 2 by the boss 5 of the primary molded body 2. After this molding, the molded body is removed from the second rod 16,
Degreasing and sintering.

In this embodiment, since the primary molded body 2 and the secondary molded body 3 can be molded in an assembled state, the assembling after molding is not required, the production efficiency is increased, and the size is reduced. Even products can be manufactured easily and with high precision. In addition, since the surface of the primary molded body is oxidized,
The wettability with the next molded body is reduced, and mutual welding during sintering does not occur. For this reason, the primary molded body and the secondary molded body can be molded in a mutually movable state. In the above description, two parts are connected. However, when many parts are connected, a large number of dies are arranged around the arm member 10 and the formed body is moved every time the second rod moves horizontally. Is formed by spraying a sodium stearate solution onto the mold, and molding the molded bodies while connecting them in the order of the mold.

Further, in this embodiment, a pair of bosses is formed on the outer peripheral surface of the primary molded body and is surrounded by the ears of the secondary molded body. That is, as shown in FIG. 12, a pair of holes 7 are formed on the outer peripheral surface of the primary molded body 2,
The boss 9 of the secondary molded body may be formed simultaneously with the formation of the ear 8 of the secondary molded body 3. (See FIGS. 11 and 13). When connecting a plurality of these two parts, it is possible to form them while forming a hole and a boss in each formed body as shown by a chain line in FIG.

[0018]

Embodiment 2 A metal part formed by ordinary cutting is attached to the second rod 16 of the arm member 10,
The product is set in the fixed mold 32 of the second injection molding machine 30 and subjected to injection molding to produce an assembled product.
In this case, the surface of the component can be subjected to a nitriding treatment in a nitrogen atmosphere at 500 ° C., whereby a movable assembled product can be obtained. In such a method, the nozzle 4
Since spraying from 1 is unnecessary, processing in a clean environment becomes possible.

[0019]

As described above, according to the present invention, an assembled sintered body can be manufactured without requiring an assembling step.

[Brief description of the drawings]

FIG. 1 is a perspective view of a sintered body manufactured according to a first embodiment of the present invention.

FIG. 2 is a sectional view of FIG.

FIG. 3 is an overall sectional view of a molding apparatus applied to the first embodiment.

FIG. 4 is a side view of the arm member.

FIG. 5 is a side view of the operation of the arm member.

FIG. 6 is a plan view of a fixed mold of the first injection molding machine.

FIG. 7 is a plan view of a movable mold of the first injection molding machine.

FIG. 8 is a plan view of a fixed mold of the second injection molding machine.

FIG. 9 is a perspective view of a fixed mold of the second injection molding machine.

FIG. 10 is a plan view of a fixed mold of the second injection molding machine.

FIG. 11 is a perspective view of another sintered body formed according to the first embodiment.

FIG. 12 is a perspective view of a primary molded body of another sintered body molded according to the first embodiment.

FIG. 13 is a sectional view of FIG. 11;

[Explanation of symbols]

 2 Primary molded body 3 Secondary molded body

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Naohito Shiga 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside O-Limpus Optical Industry Co., Ltd. (72) Michio Shirai 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside the Olympus Optical Co., Ltd. (72) Ryusuke Nozawa, Inventor 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside the Olympus Optical Co., Ltd. Kenji Haga 2-43-2, Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd. (72) Inventor Jun Inahashi 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd. (58) Field surveyed (Int. Cl. ⁷ , DB name) B22F 3 / 02 B22F 3/24 B22F 7/06

Claims (2)

(57) [Claims] An injection molding of a mixture of a metal powder or a ceramic powder and an organic binder to form a primary molded body, and after oxidizing or nitriding the surface of the primary molded body,
Injection molding a mixture of a metal powder or a ceramic powder and an organic binder so as to be connected to the primary molded body,
Thereafter, degreasing and sintering are performed. 2. After oxidizing or nitriding the surface of a component made of metal or ceramics, a mixture of metal powder or ceramics powder and an organic binder is injection-molded so as to be connected to the component, and then degreased and sintered. A method for producing a sintered body, characterized in that: