JP3280909B2 - Mold equipment for injection molding of metal raw materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding of a metal raw material for obtaining a metal molded product from a single metal raw material such as magnesium, aluminum, lead, zinc, bismuth, tin or the like or an alloy raw material thereof by a thixomolding method. The present invention relates to a mold apparatus.

[0002]

2. Description of the Related Art As a metal forming method, there are known a pressure casting method in which pressure is applied mechanically, a gravity casting method in which pressure is not particularly applied, and the like. As is well known in the art, a die casting machine used in a die casting method, which is one of the pressure casting methods, includes a press-fitting ram for press-fitting a molten metal, a fixed platen and a movable platen on which a mold is mounted, and mold-clamping these plates. It is composed of a clamping ram and the like. A cavity is formed in the mold in order to obtain a product, and a gate for injecting the molten metal into the cavity is constituted by a so-called side gate formed along a division surface of the mold. Therefore, the movable platen is clamped to the fixed platen by the mold clamping ram, and the molten metal is filled into the cavity from the side gate by the press-in ram, and after cooling and solidification, the mold is opened to obtain a metal molded product. it can. Products such as aluminum alloys, magnesium alloys, and zinc alloys are manufactured by the die casting method.

On the other hand, recently, a thixomolding method has been proposed. In this method, when the alloy raw material is stirred in a solid-liquid coexistence state, the formation of dendritic crystals, that is, dendrites, is suppressed, and a slurry-like substance in which broken fine granular solid and liquid coexist is obtained. ,
This is a method of solidifying such a slurry-like substance in a solid-liquid coexistence state in a short time to obtain a metal molded product having an alloy structure in which solids are distributed almost uniformly. Since this metal molded product has a small shrinkage rate due to solidification and a small number of microshrinkage, ie, shrinkage holes and voids due to gas entrainment, it exhibits good properties in both dimensional accuracy and mechanical properties. An injection molding machine or an extruder is used in a method for producing an alloy molded product utilizing such properties of the slurry-like substance. An injection molding machine used for performing the thixomolding method includes a heating cylinder whose temperature can be controlled. Therefore, when the screw provided in the heating cylinder is driven to rotate, the solid metal material or alloy material is sequentially moved to the tip of the heating cylinder by the screw. At this time, the metal raw material is heated to a temperature higher than the solidus temperature and lower than the liquidus temperature by the heat generated by the action of friction and shearing due to the rotation of the screw and the heat applied from the heating cylinder, and is melted. Thereafter, the temperature of the heating cylinder is controlled, maintained at the solid-liquid coexistence temperature, and measured at the tip of the heating cylinder.

[0004] A mold apparatus for injecting the measured metal material in a solid-liquid coexistence state generally includes a fixed plate and a movable plate to which a mold is attached, a mold clamping device for clamping these plates, and the like. The mold is provided with cavities or cavities in the mold to obtain a metal molding. The gate for injecting the molten metal into the cavity is constituted by a side gate provided along the dividing surface of the mold.
Therefore, when the movable platen is clamped to the fixed platen by the mold clamping device and the screw is driven in the axial direction, the measured metal material in the solid-liquid coexistence state is injected into the cavity from the side gate. After cooling and solidification, the movable platen is opened to obtain a metal molded product.

[0005]

According to the die casting method, cavities can be removed to some extent from the casting, and the quality can be improved to some extent. In addition, since it is pressurized, metal molded products of various shapes can be obtained relatively accurately. However, the mold used in the die casting method has a lot of space in the flow path of the molten metal, and this air often enters the molded part of the mold during casting, and air bubbles often remain in the casting. Molded products may not be obtained. In addition, it is difficult to control an appropriate amount of hot water, for example, within plus or minus 5%, and it is not possible to inject a pouring amount suitable for a metal molded product into a mold. In the current situation. For the above reasons, there is a limit in obtaining precision molded automobile parts, OA equipment parts, FA equipment parts, office equipment parts, electric tool parts, communication equipment essential parts, etc. by the die casting method. .

On the other hand, according to the thixomolding method, it is recognized that a solid metal material can be kept in a solid-liquid coexistence state in a cylinder using an injection molding machine, and a melting furnace is not required. In addition, since a metal molded product is obtained by injecting it into a mold by an injection molding machine, since there are few shrinkage holes and voids due to gas entrainment, a high quality metal molded product having good dimensional accuracy and mechanical properties can be obtained. It can be said that the thixomolding method is excellent. However, there is a problem because the gate for injecting the metal material in the solid-liquid coexistence state into the cavity is constituted by the side gate similarly to the gate of the mold. That is, the sprue tends to be relatively long, and the material yield of the metal molded article tends to be low. In addition, the distance from the gate to the end of the metal molded product, that is, the flow length becomes long, and hot lines, sink marks, cracks, and the like appear on the metal molded product, and the quality may not be constant. Furthermore, the solidification time of the metal material is short, so the flow stops quickly,
The filling property of a portion far from the gate is poor, and a pressure is applied to prevent sink marks, but the effect is very small. Furthermore, the mold clamping force is proportional to the area obtained by adding the projected area of the metal molded product in the mold clamping direction to the projected area of the runner and the gate in the mold clamping direction. Also, there is a disadvantage that the gate area is large and a large mold clamping force is required, and as a result, the mold clamping apparatus and the mold apparatus become large.

The present invention aims to provide a mold apparatus which has solved the problems or drawbacks of the conventional mold apparatus for molding a metal raw material as described above. Specifically, the present invention provides a high-quality mold apparatus by the thixomolding method. It is also an object of the present invention to provide a metal raw material forming apparatus capable of forming a metal molded product of the above, and which can be formed with a relatively small clamping force.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention provides a metal molded product formed from a single metal material such as magnesium, aluminum, lead, zinc, bismuth, tin or an alloy material thereof by a thixomolding method. The injection molding die apparatus for obtaining a fixed mold to which an injection machine is connected, an intermediate mold in which a part of the cavity is formed, and a movable mold in which the remainder of the cavity is formed, The fixed type includes a mounting plate to which an injection machine is connected via a sprue bush, and a runner plate formed with a runner recess communicating with a primary sprue of the sprue bush. A stop pin that regulates a stroke at which the mold is opened from the fixed mold is provided, and the intermediate mold has the intermediate mold at a stroke end of the stop pin. One of a parting lock set for holding the intermediate mold and the movable mold in a locked state until they contact each other is provided, and the movable mold is provided with a projecting device for projecting a metal molded product, and the parting lock set is provided. The fixed mold is provided with a runner lock pin for peeling off a secondary sprue and a runner formed on the intermediate mold from the intermediate mold when the mold is opened, and is formed on the runner plate. The pin gate communicating with the runner recess through the secondary sprue is configured to open to the cavity from substantially the same direction as the mold opening and closing direction. According to a second aspect of the present invention, the runner plate according to the first aspect is separated from the mounting plate by a predetermined distance, and a recess for forming a cold plug catcher is provided at a position corresponding to the sprue bush of the intermediate type. Is formed, and the invention described in claim 3 is based on claim 1
Or the shape of the tip of the runner lock pin described in 2 which is located in the runner is such that the runner does not separate when the gate is cut, and the shape or size that the runner plate separates when the runner plate separates from the mounting plate. The invention described in claim 4 is the first invention.
A plurality of cavities according to any one of the first to third aspects is formed, and a plurality of the pin gates are provided in one cavity according to the first aspect of the invention. It is configured to open.

[0009]

Embodiments of the present invention will be described below.
1 (a) and 1 (b) are schematic cross-sectional views showing a mold device according to the present embodiment in an opened state, and FIG. 2 is an enlarged view of a main part of the mold device in a state where metal material is filled. FIG. 2 is a cross-sectional view illustrating an example of forming a magnesium-based alloy threaded cap having a threaded portion N on the outer periphery as indicated by reference numeral S in FIG. As shown in FIG. 1, the mold apparatus according to the present embodiment generally includes a fixed mold 1 located on the right side, a movable mold 40 located on the left side, and a fixed mold 1 and a movable mold 40. And an intermediate mold 20 located between the two.

The fixed die 1 includes a mounting plate 2 and a runner plate 7 which is guided by guide pins 12 with respect to the mounting plate 2 and is regulated by stop pins 13 and opens at a predetermined interval. A locating ring 3 is attached to the mounting plate 2, and the sprue bush 4 is positioned by the locating ring 3. A runner recess 8 communicating with the primary sprue hole 55 of the sprue bush 4 is formed on the left surface of the runner plate 7 located to the left in FIG. The runner recess 8 forms a part of a runner 29 described later. The runner lock pin 10 is mounted on the mounting plate 2, and the bulging portion 11 at the tip thereof faces the runner 29 formed between the runner plate 7 and the intermediate mold 20.
The shape or size of the bulging portion 11 holds the runner with the gate cutting force, but the runner plate 7 is
The shape or size is selected so as to be separated when separated.

A secondary sprue 21 is formed on the intermediate mold 20 so as to be vertically aligned with the runner lock pin 10 as shown in FIG. And
The secondary sprue 21 extends vertically to the left inside the intermediate mold 20, and a tip end thereof forms a pin gate 22 as described later. The guide pin 12 has a right end fixed to the mounting plate 2 to guide the intermediate mold 20 in the mold opening and closing direction. A through-hole 9 is formed in the mounting plate 2 as shown in FIG. 1B, and a step is provided inside the through-hole 9 so that a head of the stop pin 13 is formed. When the portion 14 comes into contact with the step portion, the movement of the stop pin 13 to the left is restricted. As a result, the intermediate mold 2 is opened when the mold is opened.
0 is separated from the mounting plate 2 by an interval h, and the primary sprue 5 and the like
Release from mold. An enlarged portion 16 is also formed at the left end of the stop pin 13, and when the intermediate mold 20 contacts the enlarged portion 16, the subsequent mold opening is restricted. The stop pin 13 is provided with a spring 15 for assisting in opening the mold.

As shown in FIG. 2 in an enlarged manner, an insert 23 is attached to the intermediate mold 20, and a core 25 is provided on the insert 23. The aforementioned secondary sprue 21
Penetrates the intermediate mold 20 and the core 25, and the pin gate 22 at the tip thereof reaches the left end 26 of the core 25.
The diameter d of the pin gate 22 is 2.8 m in the present embodiment.
m. It is assumed that the gate cutting force for cutting the pin gate 22 requires a maximum of 210 kg from the mechanical property value of the magnesium alloy, that is, the tensile strength. Therefore, parting lock sets 30, 30 'provided in relation to the intermediate mold 20 and the movable mold 40 are provided.
Is selected so that it can be opened at 250 kg with a margin. A recess 27 is provided on the right side of the intermediate mold 20 at a position aligned with the sprue bush 4. The concave portion 27 forms a disk-shaped catcher 27 'during molding. Further, a second runner recess 28 that forms a runner 29 in cooperation with the runner recess 8 provided on the runner plate 7 is provided on the right surface of the intermediate mold 20.

As shown in FIG. 2, the nest 23 is formed with a concave portion 24 having an open left side. The recess 24 is for forming the head T of the metal molded product S, and forms a part of the cavity 32. The left end 26 of the core 25 described above faces the inside of the recess 24.
Therefore, the pin gate 22 is inserted into the metal molded product S from the right. That is, the pin gate 22 at the distal end of the secondary sprue 21 is inserted into a substantially central portion of the cavity 32 from substantially the same direction as the mold opening and closing direction of the movable mold 40. The left end 26 is a hexagonal core 25.
Is applied, a hexagonal hole into which a hexagonal spanner can be inserted is formed in the head T of the metal molded product S.

As shown in FIG. 1A, the intermediate mold 20 is provided with a pair of inclined pins 31, 31 extending a predetermined length to the left at a predetermined interval. I have. When the movable die 40 is closed, the inclined pins 31, 31 guide the guide holes 43, 4 of a pair of slide cores 41, 41 described later.
3, the slide cores 41, 41 are closed, and the movable mold 40 is opened when opened. Thereby, the metal molded product S having the formed screw portion N can be taken out.

The movable die 40 includes a pair of slide cores 41, 41 that slide in the left and right direction,
A support die 42 slidably supporting the first and the first 41;
A mounting frame 45 and the like are provided. A pair of slide cores 41,
Screw portions 44, 44 are formed on inner surfaces of the facing 41. The inside of the pair of screw portions 44, 44 and the insert 23
A cavity 32 is formed by the concave portion 24.
Note that the left end of the cavity 32 is closed by the distal ends of a protruding sleeve pin 46 and a protruding sleeve 48 described later. Further, a pair of guide holes 43, which spread toward each other toward the left, are formed in the pair of slide cores 41, 41.
43 are formed.

As shown in FIG. 1B, a projecting sleeve pin 46 is attached to a mounting frame 45 of the movable mold 40 by a positioning bolt 47. The left end of the protruding sleeve 48 fitted to the protruding sleeve pin 46 is fixed to a protruding plate 50 driven rightward. Accordingly, when the protruding plate 50 is driven rightward, the protruding sleeve 48 protrudes into the cavity 32. The return plate 5 is provided on the protruding plate 50.
A return pin 52 with 1 is provided. The return spring 51 is compressed when the molded product protrudes, and when the projecting plate 50 is retracted by the restoring force of the return spring 51, the projecting sleeve 48 is returned to the molding position. In addition, the intermediate mold 2
Reference numerals 53, 53,... In the movable mold 40 denote flow paths for heat medium oil or the like for controlling the temperature of the mold.

Next, an example of forming a metal molded product S which is a cap with a screw by the above-mentioned mold apparatus will be described. Although a specific example of the injection machine is not shown in the drawing, for example, an in-line screw type injection machine is used. The cylinder barrel is supplied with a magnesium alloy chip, and the screw is rotated and weighed. At this time, the heating device provided on the outer peripheral portion of the cylinder barrel is precisely controlled, and the heating is performed within + 50 ° C, preferably + 30 ° C, which is higher than the melting point. Thereby, the metal raw material in the solid-liquid coexistence state is measured.

Although not shown in the drawing, the movable mold 40 is clamped to the fixed mold 1 by a mold clamping device. Then, as shown in FIG. 2, the core 25, the insert 23,
The cavity 32 is formed by the pair of slide cores 41, 41, the protruding sleeve pin 46 and the protruding sleeve 48. The screw of the injection machine is driven in the axial direction to inject and fill the measured metal raw material. FIG. 3 shows the state after the filling is completed.

After cooling and solidification, the movable mold 40 is opened. Then, since the opening force of the parting lock sets 30, 30 'is set to be larger than the gate cutting force, before the parting lock sets 30, 30' are opened, the pin gate 22 is connected to the movable mold 40 and the intermediate mold. 20 in the mold. The cut state is shown in FIG. Further, when the movable mold 40 is opened,
The runner plate 7 is driven to the left until the head 14 of the stop pin 13 contacts the step of the through hole 9 of the mounting plate 2.
Due to this drive, a space h is generated between the mounting plate 2 and the runner plate 7, as shown in FIG. When this interval h occurs, the disk-shaped cold catcher 27 ′ formed by the concave portion 27 of the intermediate mold 20 is driven leftward at the left edge of the runner plate 7. As a result, the primary sprue 5 formed by the sprue bush 4 is released from the sprue bush 4, and the runner 29 'is released from the bulging portion 11 of the runner lock pin 10.

Further, the movable mold 40 is opened. The drive of the intermediate mold 20 to the left is restricted by the stop pin 13, and the parting lock sets 30, 30 'are opened. As a result, the movable mold 40 is separated from the intermediate mold 20 by a predetermined distance. When separated, the pair of slide cores 41, 41
Opened by the inclined pins 31, 31, the slide core 41,
The screw portions 44 of the 41 are separated from the screws of the metal molded product S. Next, the projecting plate 50 is formed by a hydraulic cylinder (not shown) or the like.
To the right. Then, the protruding sleeve 48 attached to the protruding plate 50 is also driven rightward, and the metal molded product S protrudes and falls downward. When the metal molded product S is fixed to the protruding sleeve 48, the metal molded product S is manually removed or removed by a removal robot or the like, and is removed from the mold apparatus. FIG. 5 shows a state in which the pair of slide cores 41, 41 are opened, the return spring 51 is compressed, and the metal molded product S is projected. When the driving of the protruding plate 50 to the right is stopped, the protruding plate 50 is
It returns to the original position by the restoring force of 1. Next, the movable mold 40 is clamped to the fixed mold 1. When the mold is clamped, the inclined pins 31, 31 enter the guide holes 43, 43 of the pair of slide cores 41, 41, and the slide cores 41, 41 are closed.
Thereby, the cavities 32 are formed as described above. Thereafter, injection and molding are performed in the same manner.

It is clear that the metal raw material of the present invention is not limited to a magnesium alloy. For example, a metal raw material having a melting point of 700 ° C. or less or a metal element alone or an alloy based on these metals, such as aluminum, zinc, tin, lead, bismuth, terbium, tellurium, cadmium, thallium, astatine, polonium, selenium, Obviously, lithium, indium, sodium, potassium, rubidium, cesium, francium, gallium and the like can be applied. In particular, aluminum, lead, zinc,
A simple substance of bismuth and tin and an alloy based on these metals are desirable. All of these metal raw materials are kneaded and melted by an injection molding machine such as an in-line screw type injection molding machine,
It is a metal element or alloy that can be formed. Also, the melting point of copper is 1085 ° C, which is much higher than 700 ° C,
As for the copper alloy, for example, the melting point of the copper alloy for brazing is 700 ° C. or less, and the present invention also targets the copper alloy as a metal raw material.

It is also clear that the number of pin gates is not limited to one. By providing a plurality of pin gates for one cavity, it is possible to cope with molding of a metal molded product having a high cooling rate and a large projected area, for example. Furthermore, a plurality of cavities may be provided in one mold, and each of the cavities may be provided with a pin gate that opens in these cavities from substantially the same direction as the mold opening / closing direction. This embodiment is shown in FIG.
That is, FIG. 6 is a perspective view showing only the slide cores 41 ′ and 41 ′.
Cavities 3 similar to the cavities 32 formed in the slide cores 41, 41 described above are provided in 1 ', 41'.
Three 2 ', 32', and 32 'are provided in parallel.
Although not shown in the figure, these cavities 3
Pin gates are opened at 2 ', 32', and 32 'from a direction substantially the same as the mold opening and closing direction. Therefore, according to the present embodiment, a plurality of metal molded products can be molded at once.

[0023]

As described above, according to the present invention, an injection molding die apparatus for obtaining a metal molded product from a metal raw material such as a magnesium alloy by a thixomolding method is different from a fixed die to which an injection machine is connected. An intermediate mold in which a part of the cavity is formed, and a movable mold in which the remainder of the cavity is formed, and a runner formed on a runner plate constituting a fixed mold through a secondary sprue. Since the communicating pin gate is opened to the cavity from substantially the same direction as the mold opening / closing direction, the distance from the pin gate to the cavity, that is, the flow length is shortened. And a high quality metal molded product can be obtained. In addition, the solidification time of the metal material is short, and the flow stops quickly, but since the pin gate is opened in the cavity from substantially the same direction as the mold opening / closing direction, the filling property is good and the pressure holding effect for preventing sink marks is large. . Further, according to the present invention, since the gate is constituted by the pin gate, the projected area of the runner and the gate in the mold clamping direction is small, and the mold clamping force is small. Therefore,
The mold device and the mold clamping device for clamping the mold device can be small. Further, since the pin gate is opened in the cavity substantially in the same direction as the mold opening and closing direction, the gate can be cut in the mold. Therefore, post-processing is simplified. As described above, according to the present invention, a high-quality metal molded product can be obtained with a small mold clamping force. Therefore, an injection molding die for a metal raw material for forming a large and thin metal molded product accurately and accurately. When applied as a device, further effects can be obtained. According to the second aspect of the present invention, the runner plate is separated from the mounting plate by a predetermined distance, and a recess for forming a cold plug catcher is formed at a position corresponding to the sprue bush of the intermediate mold. Therefore, an effect that the sprue and the runner can be released is added.
According to the third aspect of the present invention, the shape of the tip of the runner lock pin located in the runner is such that the runner does not separate when the gate is cut, and separates when the runner plate separates from the mounting plate. Since the shape or size is selected, the gate cut and the release of a sprue or the like can be reliably performed. According to the invention described in claim 4, since a plurality of cavities are formed,
According to the fifth aspect of the present invention, a high yield rate can be obtained, and since a plurality of pin gates are opened in one cavity, a thin, wide-area metal molded product can be obtained with high precision. The effect is further obtained.

[Brief description of the drawings]

FIG. 1 is a view schematically showing a mold device according to an embodiment of the present invention in an open state, and FIG.
(B) is a side view thereof.

FIG. 2 is an enlarged cross-sectional view showing a main part of the mold apparatus in a state where a metal raw material is filled.

FIG. 3 is a schematic cross-sectional view showing a state in which a metal raw material is filled in a mold apparatus according to an embodiment of the present invention, in which (a) is a front view thereof, and (b) is a side view thereof. It is.

FIG. 4 is a diagram schematically showing a state in the middle of mold opening as a cross section, in which (a) is a front view showing a state in which a gate is cut, and (b) is a state in which a runner plate is separated from a mounting plate. FIG.

FIG. 5 is a diagram schematically showing a state in which a mold is finished and a metal molded product is protruded in a cross section, in which (a) is a front view and (b) is a side view.

FIG. 6 is a perspective view schematically showing another embodiment of the slide core.

[Explanation of symbols]

Reference Signs List 1 fixed type 2 mounting plate 4 sprue bush 5 primary sprue 7 runner plate 8 runner recess 10 runner lock pin 11 bulge (tip) 13 stop pin 20 intermediate mold 21 secondary sprue 22 pin gate 27 recess 28 runner recess 29 runner Reference Signs List 30 Parting lock set 32 Cavity 32 'Cavity 40 Movable mold 48 Projection sleeve 50 Projection plate S Metal molded product

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B22D 17/22 B22D 17/20

Claims (5)

(57) [Claims] An injection mold apparatus for obtaining a metal molded product (S) from a single metal material such as magnesium, aluminum, lead, zinc, bismuth, tin or the like or an alloy material thereof by a thixomolding method is provided. The fixed type (1) to which the machine is connected, the intermediate type (20) in which a part of the cavity (32) is formed, and the cavity (32).
The stationary die (1) comprises a mounting plate (2) to which an injection machine is connected via a sprue bush (4), and a movable die (40) having the remaining part of the sprue bush (4). ) Comprises a runner plate (7) formed with a runner recess (8) communicating with the primary sprue (5), and the mounting plate (1) is provided with the intermediate mold (20) in the fixed mold ( A stop pin (13) for regulating a stroke opened from 1) is provided, and the intermediate mold (20) is provided on the intermediate mold (20) until the intermediate mold (20) comes into contact with a stroke end of the stop pin (13). (20) and one of a parting lock set (30) for holding the movable mold (40) in a locked state is provided. The movable mold (40) has a projection device (48, 50) for ejecting a metal molded product. Is provided On the other is provided with parting lockset (30 '), wherein the fixed die (1), the intermediate mold during mold opening (20)
From the secondary sprue (2) formed in the intermediate mold (20).
1) and a runner lock pin (10) for peeling off the runner (29 '), and a runner recess (8) formed in the runner plate (7) via a secondary sprue (21). Communicated pin gate (22)
The cavity (3) is substantially the same as the mold opening / closing direction.
2. An injection molding apparatus for injection molding a metal raw material, wherein the apparatus is open to 2). 2. The runner plate (7) according to claim 1, which is separated from the mounting plate (2) by a predetermined distance (h) and is located at a position corresponding to the sprue bush (4) of the intermediate mold (20). Is a mold device for injection molding of a metal raw material, in which a concave portion (27) for forming a cold plug catcher (27 ') is formed. 3. The tip (1) of the runner lock pin (10) according to claim 1 or 2, which is located inside the runner.
The shape of 1) is a runner (29 ') when the gate is cut.
A metal material injection molding apparatus selected to have a shape or size that does not separate, and a shape or size that separates when the runner plate (7) separates from the mounting plate (2). 4. A mold apparatus for injection molding a metal raw material, wherein a plurality of cavities (32 ′, 32 ′,...) According to claim 1 are formed. 5. The method according to claim 1, wherein
A mold apparatus for injection molding of a metal raw material, wherein a plurality of pin gates are opened in a plurality of cavities (32).