JPH06238Y2 - Dry isotropic pressure molding equipment - Google Patents

Description

[Detailed Description of the Invention] (Industrial field of application) The present invention overcomes the problems in injection molding or isotropic pressure molding of various metal and ceramic powders, and improves mass production of molded products with excellent quality. Regarding what you did.

(Prior Art) An injection molding machine and a cold isostatic pressurizing device are both commonly used means for obtaining molded products of various metals and ceramic powders. In a heating cylinder having a kneading screw shaft, the material is kneaded, and the binder in the material is melted, and this is injected into the molding die at a predetermined injection pressure and injection speed through an injection nozzle or plunger. Thus, a desired molded product is obtained, which is suitable for mass-producing relatively small parts having a complicated shape.

On the other hand, in the dry cold isotropic pressurizing device, a molding rubber mold is inserted through a pressure rubber mold into a pressure vessel capable of supplying a pressure medium, and the target material enclosed in the molding rubber mold is charged. It isotropically molded by pressurizing the pressure medium only in the circumferential direction, and is generally used for molding cemented carbide parts.

(Problems to be Solved by the Invention) Both of the above technologies have the following problems. That is, in the injection molding machine, since the molding die is a divided die, it is inevitable that a "burr" is produced in the molded product due to misalignment of the core, biting of foreign matter, or the like. If the molded product is thick and the injection pressure is low, "sinks" will occur on the surface of the molded product, and defects will easily occur in the internal structure.
In a mold having a more complicated shape, pressure loss occurs inside the mold, so that the composition density of the molded product becomes non-uniform, which causes "warpage" and "cracking" of the molded product.

On the other hand, in the dry cold isotropic pressure press, the above-mentioned problems do not occur, but when the shape of the molding rubber mold is complicated,
It is difficult to obtain a complete filling of the powder raw material into the rubber mold, and it is also difficult to completely fill the powder in all the parts to a uniform density, so that a molded product with a complicated shape cannot be obtained. However, the filling process itself was troublesome and took time.

The present invention solves the problems of both of these technologies, and utilizes the advantages of both technologies, and in a dry cold isotropic pressurizing device, the supplied raw material powder (material) is stored in a heated kneading cylinder. Mix and knead the binder in the material to a molten state, apply a predetermined injection pressure and injection speed to this to inject and fill the molding rubber mold in the pressure container from the injection nozzle, and press from the outside of the molding rubber mold. It is an object of the present invention to provide a technique capable of continuously performing a process of isostatically pressing and compression molding with a medium.

(Means for Solving the Problems) The present invention takes the following technical means in order to achieve the above-mentioned object.

That is, the present invention comprises an injection unit A for injecting the kneaded material 1 and a molding unit B for pressurizing and molding the material 1 supplied and filled from the injection unit A by isotropic pressure. A kneading screw shaft 5 is loaded in an injection cylinder 4 having an injection nozzle 9 in
The kneading screw shaft 5 is provided at its shaft end with an injection driving body 6 for applying an injection pressure and an injection speed, and at the tip of the kneading screw shaft 5, a nozzle hole 9A of the injection nozzle 9 is opened and closed. The molding unit B has a stop valve portion 5A, while the molding unit B has both ends in the axial direction closed by an upper lid 13 and a lower lid 17 and has a pressure medium supply port 19.
A pressure rubber mold 20 and a molding rubber mold 21 are housed therein, and the upper lid 13 side has a connection port 22 communicating with a molding chamber 21A in the molding rubber mold 21. It is a thing.

(Operation) According to the present invention, in the injection cylinder 4 of the injection unit A, the material 1 is kneaded by the rotation of the screw shaft 5, and the binder in the material 1 is melted by the heat action of the heating source 3. It

When the injection nozzle 9 is pressed against the connection port 22 of the molding unit B, the material 1 in the injection cylinder 4 is moved into the molding chamber 21A through the injection nozzle 9 at a predetermined injection pressure and injection speed by the operation of the injection driver 6. Feed and fill continuously.

The material 1 is supplied and filled into the molding chamber 21A by the action of injection pressure, and complete filling is performed even if the molding rubber die 21 has a complicated shape. After the material filling, the injection nozzle 9 is so-called at the connection port 22. While the nozzle is touching, the nozzle hole 9A is closed by the check valve portion 5A provided at the tip of the kneading screw shaft 5, and in this state, the pressure medium 10 is supplied from the pressure medium supply port 19 and the pressure is increased. The compressive force in the inward radial direction of the pressure rubber mold 20 is transmitted to the molding rubber mold 21, and the material in the molding chamber 21A is molded by the molding rubber mold 21 as shown in FIG.
During this molding, the injection nozzle 9 touches the connection port 22 and the check valve portion 5A closes the nozzle hole 9A. Leakage to the outside of the machine and backflow into the injection cylinder 4 are prevented.

When the predetermined molding is completed, the pressure on the molding unit B side is reduced, the side on the injection unit A side stands by at the old position, and the molded product 14 is taken out downward as shown in FIG.

Embodiment An embodiment of the present invention will be described in detail below with reference to the drawings.

1 to 4, A is an injection unit and B is a molding unit, and in the figures, the injection unit A is arranged on the upper side and the molding unit B is arranged on the lower side.
Both units A and B may be arranged left and right.

The injection unit A includes an injection cylinder 4 and a kneading screw shaft 5.
The screw shaft 5 is mounted in the injection cylinder 4 so as to be rotatable about its axis and movable in the axial direction, and the body of the cylinder 4 has the heating source 3 and the material 1 The accommodated supply hopper 2 is provided in communication. The material 1 is a powder of metal, ceramic or the like containing a binder, and the heating source 3 melts the binder.

The tip of the injection cylinder 4 has an injection nozzle 9 communicating with a nozzle hole 9A via a taper seat 9B, and the tip of the kneading screw shaft 5 is pressed by the taper seat 9B to open and close the nozzle hole 9A. Possible check valve section 5A.

At one end of the kneading screw shaft 5, a piston 5a that slides in the cylinder 4 is provided at its tail, and the piston 5a
A piston rod 6a of the injection driving body 6 is connected to the.
The injection driving body 6 is exemplified by a cylinder type, which gives an injection pressure and an injection speed, and a driving source 7 for kneading by a motor or the like is provided on the upper portion of the driving body 6, in which the screw shaft 5 is It is rotated by the drive source 7 around the axis, and
By applying a fluid pressure such as a hydraulic pressure to one of the upper and lower piston chambers in the injection driving body 6, the screw shaft 5 is moved in the injection cylinder 4 in the axial direction, and the speed and pressure at which the screw shaft 5 moves downward in the figure. Respectively become the injection speed and the injection pressure, and the injection speed can be adjusted.

The molding unit B includes a pressure vessel 11 having openings at both ends in the axial direction, and both openings are hermetically closed by a removable upper lid 13 and lower lid 17, and the pressure vessel 11 has an internal portion. It is equipped with a supply port 19 for the fluid pressure medium 10 to the inside, and is further equipped with a cylindrical pressure rubber mold 20 whose upper and lower parts are supported by upper and lower lids 13 and 17 and whose body part is elastically deformable. A cylindrical molding rubber mold 21 having a vertically-penetrating molding chamber 21A is loaded in the cylindrical pressing rubber mold 20.

A funnel-shaped connection port 22 is formed on the upper lid 13, and the connection port 22
Is formed with a gate 12 communicating with the molding chamber 21A on the axis of the pressure vessel 11, while the lower lid 17 has a punch insertion hole 17A formed on the axis of the pressure vessel 11 and this insertion hole 17A.
The lower punch 15 which is erected on the lower plate 15A is removably inserted therein.

Further, the molding unit B is provided with a pair of left and right press frames 18 which can be engaged with and disengaged from the outer peripheral end surfaces of the upper lid 13 and the lower plate 15A, and the press frames 18 can be repositioned between an engaging position and a non-engaging position. It is a rectangular frame, and at the engagement position in the figure,
It is possible to carry the axial force of the press in the axial direction due to the molding.

The lower punch 15 is inserted into and removed from the insertion / extraction hole 17A from below, so that the piston rod 16a of the fluid cylinder 16 is connected to the lower plate 15A via the bracket 15B.
The lower punch 15 is inserted / removed by expanding / contracting the fluid cylinder 16 after the position is set to the non-engagement position, and the lower punch 15, the fluid cylinder 16 and the like serve as molded product takeout means.

Furthermore, the injection nozzle 9 of the injection unit A is the molding unit B.
The injection cylinder 4 has a bracket 23 attached thereto, and the piston rod 8a of the fluid cylinder 8 is connected to the bracket 23. Here, the fluid cylinder 8 and the like are connected to the injection unit. It is a driving body for raising and lowering A.

To explain the operation of the above embodiment, FIG. 1 shows a state in which the material 1 in the hopper 2 is kneaded by the injection cylinder 4 on the injection unit A side, and the material 1 supplied from the hopper 2 is used for the motor or the like. The kneading and the binder in the material 1 are in a molten state while being heated by the screw shaft 5 rotated by the drive source 7 and the heating source 3 such as a heater. Next, in order to inject the kneaded material, the entire unit A is lowered by the unit driver 8 as shown in the second drawing, and the injection nozzle 9 of the injection cylinder 4 is joined to the connection port 22 of the upper lid 13 of the molding unit B. Let the gate
The molding chamber 21A of the molding rubber mold 21 is communicated via 12
As shown in the figure, the screw shaft 5 is operated by the injection driving body 6, and the kneaded material is injected and filled into the molding chamber 21A of the molding rubber mold 21 through the injection nozzle 9 and the gate 12.

At the time of this injection filling, the check valve portion 5A of the screw shaft 5 closes the nozzle hole 9A and the injection nozzle 9 is pressed against the connection port 22. In this state, the pressure medium 10 is supplied into the pressure rubber mold 20 to raise the pressure. Then, the filled material is subjected to isotropic pressure pressurization through pressurization of the molding rubber mold 21. During this pressurizing process, the material in the molding chamber 21A receives a compression action and tries to leak to the outside through the gate 12, but this is prevented by the nozzle touch of the injection nozzle 9, and the material is injected through the gate 12. The material that tries to flow back to the cylinder 4 is blocked by the check valve portion 5A,
Here, the compression action is performed without escaping from the molding chamber 21A.

After the isotropic pressurization is completed, the pressure medium 10 is depressurized, and the lower punch 15 on which the molded product 14 is placed is lowered by the driving body 16 shown by the lifting cylinder.
17, the molding 14 is taken out as shown in FIG. 4, and at the same time the injection unit A is raised to the old position by the unit driving body 8 and the kneading of the material is started again. It is possible to perform molding continuously as a cycle. It is also possible to heat or cool the pressure medium to heat or cool the molded product and simultaneously perform isotropic pressure molding.

(Effect of the Invention) According to the present invention, since the final product shape is determined by the molding rubber mold, there is no "burr" in the resulting molded product. Furthermore, since the molding is performed by isotropic pressure pressurization higher than the injection pressure, the occurrence of "sink" and internal defects on the surface of the molded product can be minimized, and a good product of uniform quality and excellent quality can be obtained. It is definitely obtained. On the other hand, in the molded rubber mold, the material to be molded is injected and filled under a predetermined pressure, so that even if the rubber mold has a complicated shape, the entire end can be completely and uniformly packed up to the end.

Further, during the pressurizing process, the injection nozzle can be pressed against the connection port and the nozzle hole can be closed by the check valve portion provided at the tip of the kneading screw shaft. It is possible to surely receive a compression action without escaping from the molding chamber to the outside, so that a good quality molded product can be obtained.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional front view of a kneading state according to an embodiment of the device of the present invention, FIG. 2 is a front view of the same material when it is supplied, and FIG. 3 is a same front view of the same material injecting and filling and isotropically pressurized. FIG. 4 is a front view of the same molded product taken out. DESCRIPTION OF SYMBOLS 1 ... Material, 4 ... Injection cylinder, 5 ... Screw shaft, 5A ... Check valve part, 6 ... Injection drive body, 7 ... Rotation drive source, 9 ... Injection nozzle, 9A ... Nozzle hole, 10 ... Pressure medium, 11 ... Pressure container, 12 ... Gate, 13 ... Upper lid, 14 ... Molded product, 17 ... Lower lid, 19 ... Pressure medium supply port, 20 ... Pressurized rubber mold, 21 ... Molded rubber mold, A ... Injection unit, B ... Molding unit .

Claims (1)

[Scope of utility model registration request] 1. An injection unit for injecting a kneaded material (1)
(A) and a molding unit (B) for press-molding the material 1 supplied and filled from the injection unit (A) with isotropic pressure, the injection unit (A) has an injection nozzle (9) at the tip. An injection cylinder (4) having a kneading screw shaft (5) is loaded, and an injection driver (6) for applying an injection pressure and an injection speed to the shaft end of the kneading screw shaft (5). ) Is provided at the tip of the kneading screw shaft (5), and a check valve portion (5A) that allows the nozzle hole (9A) of the injection nozzle (9) to be opened and closed freely is provided. Both ends of the unit (B) in the axial direction are closed by the upper lid (13) and the lower lid (17), and the pressure medium supply port (1
A pressure rubber mold (20) and a molding rubber mold (21) are housed in a pressure vessel (11) having 9), and the molding in the pressure rubber mold (21) is made on the side of the upper lid (13). Connection port (22) that communicates with the room (21A)
A dry-type isotropic pressure-pressing apparatus having: