JP7635968B2 - Metal forming apparatus and method - Google Patents

Description

This invention relates to a metal forming device and a metal forming method, and in particular to a technology that combines a die casting method, which is suitable for mass production of light, thin, short and small metal products consisting of thin-walled parts, with a high-temperature press processing method.

In addition to direct cutting, many aluminum products are produced by casting using sand molds, such as gravity casting, and die casting using metal molds.
In particular, die casting is used industrially as a method for producing small products such as heat sinks as well as large products such as engine blocks.

Structure of a die casting machine: Basic knowledge of die casting 3 Internet URL: https://www.ipros.jp/technote/basic-die-cast3/ Retrieved on: February 1, 2021 About Die Casting Internet URL: http://www.tokyodiecast.co.jp/diecast/ Search date: February 1, 2021

There are two main types of this process: cold runner and hot runner. However, the principle of pouring molten aluminum into a mold cavity, cooling it, and removing the product is the same for both.
Therefore, it is essential to have a large heating furnace to melt the aluminum ingot, transport the molten aluminum into the cavity via a relatively long flow path such as a runner, clamp the split mold under pressure, cast and retain the molten aluminum in the mold cavity, and then cool the mold.

Furthermore, in order to fully fill the mold and prevent shrinkage during cooling, it is necessary to cast parts other than the product, and the product yield drops significantly as the product becomes smaller and its shape becomes more complex.
In other words, the essential elements are (1) a heating furnace for melting, (2) a mechanism for applying clamping force, (3) an increase in excess area and a decrease in yield rate to ensure uniform pouring and prevent shrinkage during cooling, and (4) forced cooling using multiple flow paths in the mold.

In light, thin, short and small aluminum products consisting of thin-walled sections, such as aluminum heat sinks, aluminum terminals, and aluminum parts related to electronic information, the amount of material poured in one casting is minute. In addition, shortening the takt time, ensuring precision in thin walls, and improving the yield rate of aluminum material are all essential for cost competition. Therefore, the above-mentioned (1) to (4), which are necessary for conventional die casting, place a heavy burden on production facilities.
In the case of die casting, efforts are being made to shorten the tact time per product and improve yields by using a multi-cavity mold structure, but it is extremely difficult to ensure the thin-wall precision required for light, thin, short and small aluminum parts, and to achieve high-quality control of the molten aluminum flow.
Furthermore, there is a strong demand to use the as-cast material produced by die casting as a base and immediately thereafter perform press working or additional injection molding using a different metal material to easily and quickly produce products with more complex shapes.

This invention was devised to solve the above-mentioned problems of the conventional technology, and aims to provide a metal forming technology that satisfies the production requirements for light, thin, short and small products, is highly suitable for mass production, and can also handle the finishing of complex shapes.

In order to achieve the above object, the metal forming device described in claim 1 comprises a metal injection unit, a first lifting mechanism for vertically reciprocating the metal injection unit, a high-temperature press forming unit, a second lifting mechanism for vertically reciprocating the high-temperature press forming unit, and a turntable, the metal injection unit comprises a heat-resistant nozzle into which a material metal is filled, an induction heating coil surrounding the heat-resistant nozzle and heating and melting the material metal by passing electricity through it, an upper casting mold connected to the lower end opening of the nozzle via an inlet, and a material introduction path, the high-temperature press forming unit comprises a press mold and a heater for heating it, and a press mold is placed on the turntable. A lower casting mold is disposed on the upper die, and the lower casting mold is inverted and transported to a position below the upper casting mold and a position below the upper press mold by rotating the turntable. When the lower casting mold is transported to a position below the upper casting mold, the metal injection unit is lowered by the first lifting mechanism, and the molten metal in the nozzle is injected into the mold space between the upper and lower casting molds to form an as-cast material. When the lower casting mold is transported to a position below the upper press mold, the high-temperature press molding unit is lowered by the second lifting mechanism, and the as-cast material on the lower casting mold is subjected to high-temperature press processing by the press mold.

The metal molding device described in claim 2 is the device of claim 1, characterized in that two lower casting molds are arranged on the turntable, and when one lower casting mold is positioned below the metal injection unit, the other lower casting mold is positioned below the high-temperature press unit.

The metal forming device described in claim 3 is the device of claim 1 or 2, characterized in that the heat-resistant nozzle includes a heated portion surrounded by the induction heating coil, an insulating spacer portion connected to the heated portion, and a tubular heat absorber loaded into the insulating spacer portion, and the material metal granules are filled into the heated portion of the heat-resistant nozzle via the material introduction path and the heat absorber.

The metal forming device described in claim 4 is the device of claim 3, characterized in that the heat absorber has an upper end opening located on the material introduction path side and a lower end opening located on the upper end opening side of the heated part, and a narrowed portion having a smaller diameter than the lower end opening is formed between the two openings.

The metal forming device described in claim 5 is the device described in claims 1 to 4, characterized in that the heat-resistant nozzle, the induction heating coil, and the upper casting mold have multiple inlet ports, and the lower end opening of the heat-resistant nozzle is connected to each inlet port.

The metal forming device described in claim 6 is the device described in claims 3 to 5, characterized in that a needle pin that can reach at least the vicinity of the boundary between the heated part of the heat-resistant nozzle and the insulating spacer part is arranged above the insulating spacer part so that it can be raised and lowered freely.

The metal forming device described in claim 7 is the device described in claims 3 to 6, characterized in that an air inlet pipe is provided above the insulating spacer section, and the material metal molten in the heated section is injected into the mold space by compressed air discharged from the air inlet pipe.

The metal forming method described in claim 8 is a metal forming method using the metal forming device of claims 1 to 7, and is characterized by comprising the steps of: lowering the metal injection unit and overlapping the upper and lower casting dies to form a die space between them; introducing material metal granules into the heat-resistant nozzle through the material inlet; passing an electric current through the induction heating coil to heat and melt the material metal granules; filling the die space with the molten material metal from the inlet; lifting the metal injection unit after the material metal has cooled and solidified to expose the as-cast material in the lower casting die; rotating the turntable to transfer the as-cast material below the high-temperature press molding unit; and lowering the high-temperature press molding unit and performing high-temperature press processing on the as-cast material using a press die.

The metal forming method described in claim 9 is the metal forming method described in claim 8 using the metal forming device described in claim 2, and is characterized by comprising the steps of: rotating the turntable to transfer the press-molded body on the lower casting die to below the metal injection unit after the high-temperature press processing is completed, replacing the upper casting die of the metal injection unit with a new upper casting die having a different shape, lowering the metal injection unit to overlap the new upper casting die and the lower casting die on which the press-molded body is placed, thereby forming a die space between them, introducing material metal granules having different melting points into the heat-resistant nozzle through the material introduction path, passing an electric current through the induction heating coil to heat and melt the material metal granules, filling the die space with the molten material metal from the introduction port, and raising the metal injection unit after the material metal has cooled and solidified, and removing the composite molded body from the lower casting die.

The metal forming method described in claim 10 is the metal forming method described in claim 8 using the metal forming device described in claim 6, characterized in that the metal injection unit is raised and then the needle pin is lowered, and a shutter consisting of a mass of semi-molten metal granules formed near the boundary between the heated part of the heat-resistant nozzle and the insulating spacer part is crushed, thereby refilling the heated part of the heat-resistant nozzle with material metal granules, and proceeding to the forming of the next as-cast material.

Unlike conventional aluminum die casting, the present invention has the following characteristics:
(1) By directly heating the heat-resistant nozzle that holds the raw metal such as aluminum metal or aluminum alloy material with an induction heating coil, a melting furnace is not required. In addition, there is no need for a large-scale mechanism for injecting molten metal into a mold at high pressure.
(2) Instead of using a conventional split mold, which requires a clamping force loading mechanism to clamp the mold, direct casting into a mold integrated with a heat-resistant nozzle makes it possible to minimize or eliminate the clamping force.
(3) One or many products are cast by direct pouring from a heat-resistant nozzle into the mold cavity, so no excess material is produced other than at the gate.
(4) The mold heating and holding temperatures can be kept low, simplifying the mold cooling mechanism.
(5) A heat insulating spacer is provided between the heated part of the heat resistant nozzle and the material introduction passage, and the heat from the heated part is absorbed by the heat absorber, so that the material metal granules waiting outside the heated part can be effectively prevented from melting. As a result, after the product is removed from the mold space, it is possible to move on to the next molding.
(6) Even if a shutter consisting of a mass of semi-molten metal granules is formed near the boundary between the heated part and the insulating spacer part due to heat conduction from the heated part and the supply of the material metal granules is hindered, it is possible to refill the material metal granules into the processed part by lowering the needle pin to break the shutter.
(7) By increasing the number of heat-resistant nozzles and induction heating coils depending on the size and complexity of the product, more flexible and efficient molding is possible.
(8) After the as-cast material is formed by the metal injection unit, the turntable is rotated to transport the lower casting mold on which the as-cast material is placed to below the high-temperature press molding unit, where the required press molding can be performed immediately, making it possible to simply and quickly finish press-molded products with more complex shapes.
Furthermore, by rotating the turntable to move the lower casting mold on which the press-molded product is placed to below the metal injection unit, and then lowering the metal injection unit equipped with a different mold shape to pour in molten metal with a different melting point, it is possible to finish the molded product into a composite product with a more complex shape.

FIG. 1 is a schematic diagram illustrating the basic principle of the present invention. Photograph showing how raw metal granules are melted directly inside a heat-resistant nozzle by the action of an induction heating coil. 4 is a graph showing how the temperature inside a heat-resistant nozzle rises rapidly due to the action of an induction heating coil. This is a photograph taken with a high-speed camera showing molten aluminum freely spraying out from the nozzle opening of a heat-resistant nozzle. 1 is a cross-sectional view showing the structure and manufacturing process of a die-casting device. 1 is a cross-sectional view showing the structure and manufacturing process of a die-casting device. 1 is a cross-sectional view showing the structure and manufacturing process of a die-casting device. 1 is a cross-sectional view showing the structure and manufacturing process of a die-casting device. 1 is a cross-sectional view showing the structure and manufacturing process of a die-casting device. 1 is a perspective view illustrating an exterior case of a smartphone manufactured by a die casting device. 1 is a cross-sectional view showing the structure and manufacturing process of a die-casting device. 1 is a cross-sectional view showing the structure and manufacturing process of a die-casting device. FIG. 1 is a schematic side view showing the structure of a metal forming device to which a die-casting device is applied. FIG. 1 is a schematic plan view showing the structure of a metal forming device to which a die-casting device is applied. 1A and 1B are diagrams showing as-cast products and press compacts formed by a metal forming apparatus. Photographs showing examples of as-cast materials and press-formed bodies formed by a metal forming device. 1A-1C show as-cast products, press compacts, and composite compacts formed by a metal forming apparatus. 1 shows an example of defect evaluation of as-cast material by X-ray CT, and photographs of a test specimen decorated by anodizing. This is a photograph showing an example of transfer molding of many fine recesses in a houndstooth pattern onto an as-cast material.

FIG. 1 is a schematic diagram for explaining the basic principle of the present invention, and comprises a steel heat-resistant nozzle 10 and a high-frequency induction heating (IH) coil 12 surrounding the heat-resistant nozzle 10 at a predetermined distance.
The heat-resistant nozzle 10 is filled with pellet-shaped metal granules (aluminum metal, aluminum alloy material, etc.) 14 (see FIG. 2(a)).
Reference numeral 18 in the figure denotes a magnetic field generated by energizing the induction heating coil 12 .

This process technique does not have a furnace, but rather uses induction heating coils 12 to melt the raw metal granules 14 directly in situ within a heat resistant nozzle 10 which holds, melts and ejects the raw metal granules 14 .
That is, when a high frequency current (for example, 400 KHz) is applied to the induction heating coil 12, the material metal granules 14 immediately melt within the heat-resistant nozzle 10, as shown in Figs. 2(b) and 2(c).

The material metal 14 and the heat-resistant nozzle 10 are directly heated by Joule heat, which is the product of the magnetic flux generated by the induction heating coil 12 and the induced current generated in the material metal granules 14 and the heat-resistant nozzle 10, and can reach the melting temperature extremely quickly.
For example, as shown in FIG. 3, the temperature inside the heat-resistant nozzle 10 rises rapidly from 28.4° C. to 755.1° C. in about one minute after the start of heating.
This graph shows that it takes about 30 seconds to reach the aluminum melting temperature of 650°C.

The molten material metal 14 falls to the outside from a nozzle opening 16 formed at the lower end of the heat-resistant nozzle 10 .
FIG. 4 is a photograph taken with a high-speed camera of molten aluminum freely ejecting from the nozzle opening 16 of the heat-resistant nozzle 10, and shows the arrival time (numbers in the upper row) and velocity (numbers in the lower row) at 10 mm intervals (10 mm per division).
As shown in Figure 4(b), it can be confirmed that the ball is ejected at a high speed that far exceeds the target value of 100 mm/s from the very beginning of the drop.

Figure 5 shows a die-casting device 20 that applies the above-mentioned basic principle, and is equipped with a pair of heat-resistant nozzles 22, a pair of induction heating coils 24 that surround each heat-resistant nozzle 22 at a specified distance, an upper casting mold (cavity) 26, and a lower casting mold (core) 28.

Each heat-resistant nozzle 22 includes a cylindrical heated portion 30 made of steel and a cylindrical heat insulating spacer portion 31 connected to the upper end thereof.
The lower end of the heated portion 30 narrows in diameter in a funnel shape, and a nozzle opening (lower end opening) 32 is formed at the lowest end portion.
The induction heating coil 24 is disposed so as to surround the periphery of the part to be heated 30 .

The diameter of the heat insulating spacer portion 31 is larger than the diameter of the heated portion 30, and a step portion 33 formed between them has a tubular heat absorber 34 made of steel or the like fitted therein.
A lower end opening 35 of the heat absorber 34 communicates with an upper end opening 36 of the heated portion 30 .
The upper end opening 37 of the heat sink 34 has a diameter substantially equal to that of the lower end opening 35, but is provided with a narrowed portion 38 having a smaller diameter midway therebetween.
As a result, the cross-sectional shape of the heat absorber 34 becomes thick overall, and a funnel-shaped material guide portion 39 and a material standby portion 40 having a reverse tapered cross-section are formed.

A tubular introduction portion 41 is connected in communication with the upper end opening 37 of the heat insulating spacer portion 31 .
A material introduction pipe 42 is connected to one side of the introduction portion 41 at a predetermined inclination angle.
An air introduction pipe 43 is connected in communication with the other side surface of the introduction portion 41 .
A needle pin holding member 45 is joined to the upper end opening 44 of the introduction portion 41. A needle pin 46 is inserted into a through hole of the needle pin holding member 45 so as to be movable up and down.

The upper casting mold 26 has a relatively shallow recess 48 formed in its inner surface, and also has a pair of inlets (gates) 49 formed therein.
The heat-resistant nozzles 22 and the upper casting mold 26 are positioned and fixed by a jig (not shown) so that the introduction ports 49 of the upper casting mold 26 communicate with the nozzle ports 32 of the heat-resistant nozzles 22 .
The lower casting mold 28 is placed and fixed on a processing table (not shown), and has a relatively low protrusion 50 formed on its upper surface.

The upper casting mold 26, the pair of heat-resistant nozzles 22 and the induction heating coil 24 are movable up and down by a lifting mechanism consisting of a hydraulic cylinder or the like (not shown).
Then, when the upper casting mold 26 is lowered and its lower end surface is pressed against the upper end surface of the lower casting mold 28, a mold space 51 is formed between the recessed portion 48 and the protruding portion 50 as shown in FIG.
In this state, when the material metal granules 14 are supplied from the material introduction pipe 42 into the introduction portion 41 , the material metal granules 14 pass through the heat absorber 34 and fill the heated portion 30 of the heat-resistant nozzle 22 .
At this timing, the needle pin 46 descends into the heat absorber 34 and repeats up and down movements several times, thereby compacting the material metal granules 14 and increasing their density.

Next, a high-frequency current is passed through the induction heating coil 24 to heat the material metal granules 14 in the heated portion 30, and at the same time, high-pressure air is supplied from the air inlet pipe 43 into the inlet portion 41. As shown in Figures 7 and 8, the molten material metal 52 is injected from the nozzle opening 32 and spreads into the mold space 51 through the inlet port 49.

After that, when the material metal 52 has cooled and solidified, as shown in FIG. 9, the heat-resistant nozzle 22 and the upper casting mold 26 are raised and separated from the lower casting mold 28, and the product 54 is removed by ejecting the ejector pin 53 embedded in the lower casting mold 28.

In addition to their excellent electrical and thermal properties, aluminum metal and aluminum alloy parts also have a high specific strength, which is an important factor for them. In electrical components, they are used as a substitute for copper terminals, in heat transfer components as heat sinks, and in high specific strength components such as the exterior parts of mobile phones.
By significantly reducing the energy costs, takt time, and amount of excess material during production, the scope of use of aluminum metal and aluminum alloys will be expanded.
In particular, for light, thin, short and small parts, die casting of thin plate structures of 2 mm or less is possible without generating burrs that reduce the dimensional accuracy.

Figure 10 shows a metallic exterior case for a smartphone, which is an example of a product 54. There is only a slight cylindrical excess portion (gate portion) 55 protruding from the gate-compatible portion, and no burrs or other defects are present.

Because the material metal granules 14 are constantly being supplied to the introduction section 41 through the material introduction pipe 42, the upper casting mold 26, the pair of heat-resistant nozzles 22, and the induction heating coil 24 should be lowered as is and the next molding should begin. However, as shown in FIG. 11, a shutter section 56 is formed at the boundary between the heated section 30 and the insulating spacer section 31, where semi-molten metal granules form a mass through point contact with each other. This acts as a lid, and so the material metal granules 14 cannot be filled into the heated section 30.

As shown in FIG. 12, the needle pin 46 is lowered to crush the shutter portion 56. As a result, the material metal granules 14 are filled into the heated portion 30, so that the next molding process can be started.

That is, after the material metal granules 14 are compacted by the up and down movement of the needle pin 46, the material metal granules 14 are melted together with the fragments of the shutter portion 56 by passing current through the induction heating coil 24, and the molten material metal 52 is injected into the mold space 51 by supplying high-pressure air.
By repeating the above procedure, it becomes possible to continuously cast the metal material into the die space 51, and the productivity of the product 54 can be improved significantly.

Since the method adopted is to set the material metal granules 14 in the heat-resistant nozzle 22 connected to the mold space 51 and heat them with the induction heating coil 24, it is possible to inject the molten material metal 52 into the mold space 51 simply by applying high-pressure air, without the need for a large-scale injection plunger or injection sleeve as in the conventional method.
Although not shown, a shutoff valve is provided upstream of the material introduction pipe 42 as a measure to prevent leakage of high-pressure air.

The shutter portion 56 is formed when the material metal granules 14 waiting in the heat insulating spacer portion 31 are semi-melted by heat conduction from the heated portion 30 .
As described above, the thick heat absorber 34 is fitted in close contact with the inner surface of the heat insulating spacer portion 31 to absorb and diffuse heat from the heated portion 30. In addition, the cross section is formed in an inverse tapered shape to prevent the molten metal material from adhering to the inner wall surface of the heat absorber 34.
As a result, the melting of the waiting material metal granules 14 due to the heat from the heated portion 30 is largely suppressed (if the double-structure insulating spacer portion 31 is not provided, the material metal granules 14 in the introduction portion 41 may melt due to heat conduction from the heated portion 30), but since there is still a possibility that some shutter portions 56 may be formed, the material metal granules 14 are forcibly crushed using the needle pin 46 as described above.

The number of the heat-resistant nozzles 22 is not particularly limited, and can be increased or decreased as appropriate depending on the size of the workpiece and the complexity of its shape.
In addition, a large number of heat-resistant nozzles 22 may be provided, and during the initial processing, some of the heat-resistant nozzles 22 and the upper casting die 26 may be used to form an intermediate part of a predetermined shape and material. Then, the upper casting die 26 may be replaced with one of a different shape, and the remaining heat-resistant nozzles 22 containing metal granules of a different material may be used to perform additional processing on the intermediate part to produce a different shape and material.

Figure 13 shows a metal molding device 70 that uses this die-casting device 20, and includes a turntable 71, a first lower casting die 28a arranged on the upper surface of the turntable 71, a second lower casting die 28b, a metal injection unit 72, and a high-temperature press molding unit 73.

The metal injection unit 72 is a concept that represents the part of the die-casting device 20 excluding the lower casting mold 28, and is composed of a pair of heat-resistant nozzles 22, an induction heating coil 24, an upper casting mold 26, etc.

The high-temperature press molding unit 73 is equipped with a main body 74 with a built-in heater and a press die 75 that is detachably attached to the underside of the main body 74, and can be raised and lowered by a lifting mechanism such as a hydraulic cylinder (not shown).

The first lower casting mold 28a and the second lower casting mold 28b are disposed at positions spaced 180 degrees apart from each other with respect to the rotation axis 76 of the turntable 71 as the center, as shown in FIG.
In addition, although both basically have the same mold shape (convex and concave), they are arranged in inverted directions (up and down, left and right reversed).
Therefore, when the turntable 71 makes a half rotation, the positions and orientations of the first lower casting mold 28a and the second lower casting mold 28b are switched.

The metal injection unit 72 is positioned on the left side of the figure, and its upper casting mold 26 has a mold shape corresponding to the first lower casting mold 28a or the second lower casting mold 28b when positioned on the left side.
Moreover, the high-temperature press molding unit 73 is located on the right side of the figure, and its press die 75 has a mold shape corresponding to the first lower casting die 28a or the second lower casting die 28b when positioned on the right side.

In the case of this metal forming device 70, the metal injection unit 72 and the high-temperature press molding unit 73 can operate independently, making it possible to manufacture products with complex shapes that combine casting and press molding extremely efficiently.

FIG. 15 shows an example of this. First, a metal injection unit 72 is lowered to inject material metal into the mold space formed between the upper casting mold 26 and the first lower casting mold 28a, thereby forming an as-cast material 77 having the shape shown in FIG. 15(a).
The as-cast material 77 has a central flat plate portion 78 and protruding pieces 79 disposed on both sides thereof. Each protruding piece 79 has a slight excess portion 55 formed therein corresponding to the inlet 49 of the upper casting mold 26.
The dimensions of the as-cast material 77 are width: 70 mm × length: 22 mm × thickness: 2.5 mm.
FIG. 16(a) is a photograph showing an example of this as-cast material 77.

Next, when the turntable 71 is rotated 180 degrees in a predetermined direction, the first lower casting mold 28a and the as-cast material 77 formed thereon are moved in an inverted state below the high-temperature press molding unit 73.
Here, the main body 74 of the high-temperature press molding unit 73 is lowered, and a press die 75 that has been heated by a heater to the thixotropic temperature range where solid and liquid coexist or to a temperature range where there is low deformation resistance is pressed against the as-cast material 77 with a prescribed pressure, thereby obtaining a press-molded body 81 in which a jagged microtexture 80 corresponding to the shape of the press die 75 is transferred to the flat plate portion 78 of the as-cast material 77, as shown in Figure 15(b).
FIG. 16( b ) is a photograph showing an example of this press-formed body 81 .

While the pressing is being carried out by the high-temperature press molding unit 73, the next as-cast material 77 is being formed by the second lower casting die 28b located on the opposite side and the upper casting die 26 of the metal injection unit 72.
Then, when the press-molded body 81 is removed from the first lower casting die 28 a , the turntable 71 rotates 180 degrees in the opposite direction, and the press-molding is performed by the high-temperature press molding unit 73 .
In this way, the metal injection unit 72 and the hot press molding unit 73 perform processes simultaneously and continuously, thereby enabling extremely efficient production of metal parts.

FIG. 17 shows an example in which a metal injection unit 72 and a hot press molding unit 73 work together to realize a more complicated molding.
First, as in the above, the metal injection unit 72 is lowered and the material metal is injected into the mold space formed between the upper casting mold 26 and the first lower casting mold 28a, thereby forming the as-cast material 77 having the shape shown in FIG. 17(a) (first step).

Next, the turntable 71 is rotated 180 degrees, and the first lower casting mold 28 a and the as-cast material 77 formed thereon are transferred to below the high-temperature press molding unit 73 .
At this point, the press die 75 heated by the heater is lowered and pressed against the as-cast material 77 with a prescribed pressure, whereby a concave pattern 82 corresponding to the shape of the press die 75 is transferred onto the surface of the as-cast material, as shown in FIG. 17(b) (second step).
The excess portions 55 formed on both ends of the as-cast material 77 are removed during this press molding process.

During this time, the metal injection unit 72 is replaced with a metal injection unit 72 having an upper casting mold 26 with a different mold shape.
Next, the turntable 71 is rotated 180 degrees in the opposite direction, and the first lower casting die 28a and the press-molded body 83 are transferred in an inverted state to below the metal injection unit 72, after which a new upper casting die 26 is lowered.
Then, by additional processing such as injecting another aluminum alloy having a lower melting point into the die space formed between the upper casting die 26, the first lower casting die 28a, and the press-formed body 83, a composite molded body 85 having a protrusion 84 is formed, as shown in Figure 17 (c) (third process).

This composite molded body 85 has a complex shape with protruding parts 84 projecting in the thickness direction by filling the recessed pattern 82 formed by press molding in FIG. 17(b) with a metal material.
Each protruding piece 79 is newly formed with a surplus portion 55 corresponding to the inlet 49 of the upper casting mold 26 .

When carrying out the third step, there is also a method in which it is sufficient to replace only the upper casting mold 26, without replacing the metal injection unit 72 itself as described above.
In other words, the first step is carried out using only one of the pair of heat-resistant nozzles 22, and when carrying out the third step, additional processing is carried out using the other heat-resistant nozzle 22 filled with metal granules of a different material and a new upper casting mold 26.

The manufacturing patterns using the metal forming device 70 are not limited to those described above.
For example, a preformed as-cast material 77 can be set in the lower casting mold 28 arranged on the right side, and after pressing to form a recess by the high-temperature press molding unit 73, the turntable 71 is rotated half a turn, and a protrusion can be formed by the metal injection unit 72 arranged on the left side.
Thereafter, the turntable 71 is rotated a half turn in the opposite direction, and the high-temperature press molding unit 73 with the press die 75 replaced can be used to perform additional press working on the protruding portion.

The number of lower casting dies provided on the turntable 71 is not limited to two, but may be at least one, or may be three or more.
For example, three lower casting dies 28a, 28b, 28c are provided on a turntable 71, and two metal injection units 72 and one hot press molding unit 73 are provided.
In this manner, when the three lower casting dies 28a, 28b, 28c are provided on the turntable 71, the turntable 71 is designed to rotate in forward and reverse directions in increments of, for example, 90 degrees instead of rotating in increments of 180 degrees, and when the turntable stops, the metal injection unit 72 and the high-temperature press molding unit 73 are located above each lower casting die.

From the viewpoint of ensuring quality, it is desirable to remove each in-process item or finished product from the first lower casting die 28a or the second lower casting die 28b by a robot hand each time the as-cast material 77, the press-molded bodies 81, 83, or the composite molding 85 is formed, and to perform non-destructive testing using X-ray CT during the production line.
FIG. 18(a) shows an example of defect evaluation of an as-cast material 77 by X-ray CT.
Since no black defects (shrinkage cavities) were observed in the plate-shaped as-cast material 77, it was possible to confirm the defect-free soundness of the work-in-progress after injection molding.

Aluminum and aluminum alloy final products are often decorated and painted using an anodizing process.
In anodizing, a fine porous aluminum oxide film is formed on the final surface, and various colors are applied by injecting dye into the columnar pores. Therefore, if the surface properties of the final product are not uniform, the coloring is likely to be uneven.
Figure 18(b) shows a test piece decorated in blue (appears black in the drawing) by anodizing. No turbidity or shading was observed in the blue color, and it was a deep blue color, proving that the surface quality of the final product was also good.

In the high-temperature press molding unit 73, by changing the press die 75, various shapes can be imparted to as-cast material or commercially available aluminum or aluminum alloy plate material.
FIG. 19 shows a microtexture formed by transferring recesses of φ50 μm in a houndstooth pattern at a pitch of 100 μm.

10 Heat-resistant nozzle
12 Induction heating coil
14 Material Metal Granules
16 Nozzle mouth
18 Magnetic Field
20 Die casting equipment
22 Heat-resistant nozzle
24 Induction heating coil
26 Upper Casting Mold
28 Lower Casting Mold
28a Lower casting mold
28b Lower casting mold
30 Heated part
31 Insulation spacer part
32 Nozzle mouth
33 Step
34 Heat sink
38 Narrowed part
39 Material Guide Section
40 Material waiting area
41 Introduction
42 Material introduction pipe
43 Air intake pipe
45 Needle pin holding member
46 Needle Pin
48 Recess
49 Introduction
50 Convex
51 Mold space
52 Material Metal
53 Ejector pin
54 products
55 Surplus parts
56 Shutter section
70 Metal forming equipment
71 Turntable
72 Metal Injection Unit
73 High temperature press molding unit
74 Main body
75 Press mold
76 Rotational Axis
77 Cast material
80 Micro Texture
81 Press-molded body
82 Concave pattern
83 Press Molding
84 Convex
85 Composite molding

Claims (10)

A metal injection unit;
a first lifting mechanism for vertically reciprocating the metal injection unit;
A high-temperature press molding unit;
a second lifting mechanism for vertically reciprocating the high-temperature press molding unit;
Equipped with a turntable,
The metal injection unit includes a heat-resistant nozzle filled with material metal granules, an induction heating coil surrounding the heat-resistant nozzle and heating and melting the material metal granules by energizing the coil, an upper casting mold connected to a lower end opening of the heat-resistant nozzle via an inlet, and a material inlet passage;
The high-temperature press molding unit includes a press mold and a heater for heating the press mold,
A lower casting mold is disposed on the turntable;
By rotating the turntable, the lower casting mold is inverted and transferred to a position below the upper casting mold and a position below the press mold .
when the lower casting mold is transferred to a position below the upper casting mold, the metal injection unit is lowered by the first lifting mechanism, and the molten metal in the heat-resistant nozzle is injected into a mold space between the upper casting mold and the lower casting mold to form an as-cast material;
A metal forming device characterized in that, when the lower casting mold is moved to a position below the press mold , the high-temperature press forming unit is lowered by the second lifting mechanism, and the press mold performs high-temperature press processing on the as-cast material on the lower casting mold. Two of the lower casting molds are disposed on the turntable;
2. The metal forming apparatus of claim 1, wherein when one lower casting die is located below the metal injection unit, the other lower casting die is located below the hot press forming unit . The heat-resistant nozzle includes a heated portion surrounded by the induction heating coil;
A heat insulating spacer portion connected to the heated portion;
A tubular heat sink is provided in the insulating spacer portion,
3. The metal forming apparatus according to claim 1, wherein the material metal granules are filled into the heated portion of the heat-resistant nozzle via the material inlet passage and the heat absorber. The heat absorber has an upper end opening located on the material introduction passage side and a lower end opening located on the upper end opening side of the heated portion,
4. The metal forming apparatus according to claim 3, further comprising a narrowed portion between the openings, the narrowed portion having a smaller diameter than the lower end opening. A plurality of inlets for the heat-resistant nozzle, the induction heating coil, and the upper casting mold are provided;
5. The metal forming apparatus according to claim 1, wherein the lower end opening of the heat-resistant nozzle is connected to each of the inlets. 5. The metal forming apparatus according to claim 3, further comprising a needle pin capable of reaching at least a portion near the boundary between the heated portion of the heat-resistant nozzle and the insulating spacer portion, the needle pin being arranged above the insulating spacer portion so as to be able to rise and fall. A metal forming apparatus as described in any one of claims 3, 4 or 6, characterized in that an air inlet pipe is provided above the insulating spacer portion, and the material metal molten in the heated portion is injected into the mold space by compressed air released from the air inlet pipe . A metal forming method using the metal forming apparatus according to any one of claims 1, 3 to 5 or 7 ,
lowering the metal injection unit to overlap the upper and lower casting dies to form a die space therebetween;
introducing raw metal granules into the heat-resistant nozzle through the raw material inlet passage;
applying an electric current to the induction heating coil to heat and melt the material metal granules;
charging molten material metal into the die cavity through the inlet;
raising the metal injection unit after the starting metal has cooled and solidified to expose the as-cast material in the lower casting mold;
rotating the turntable and transporting the as-cast material to a position below a high-temperature press molding unit;
a step of lowering a high-temperature press molding unit and subjecting the as-cast material to high-temperature press processing using a press die;
A metal forming method comprising: A metal forming method using the metal forming apparatus according to claim 2,
lowering the metal injection unit to overlap the upper and lower casting dies to form a die space therebetween;
introducing raw metal granules into the heat-resistant nozzle through the raw material inlet passage;
applying an electric current to the induction heating coil to heat and melt the material metal granules;
charging molten material metal into the die cavity through the inlet;
raising the metal injection unit after the starting metal has cooled and solidified to expose the as-cast material in the lower casting mold;
rotating the turntable and transporting the as-cast material to a position below a high-temperature press molding unit;
a step of lowering a high-temperature press molding unit and subjecting the as-cast material to high-temperature press processing using a press die;
After the high-temperature pressing is completed, the turntable is rotated to transfer the press-molded body on the lower casting die to below the metal injection unit;
replacing the upper casting die of the metal injection unit with a new upper casting die having a different mold shape;
a step of lowering a metal injection unit to overlap a new upper casting die with the lower casting die on which the press-molded body is placed, thereby forming a die space between the two;
introducing material metal granules having different melting points into the heat-resistant nozzle through the material inlet passage;
applying an electric current to the induction heating coil to heat and melt the material metal granules;
charging molten material metal into the die cavity through the inlet;
After the raw metal is cooled and solidified, the metal injection unit is raised to remove the composite compact from the lower casting mold.
A metal forming method comprising: A metal forming method using the metal forming apparatus according to claim 6,
lowering the metal injection unit to overlap the upper and lower casting dies to form a die space therebetween;
introducing raw metal granules into the heat-resistant nozzle through the raw material inlet passage;
applying an electric current to the induction heating coil to heat and melt the material metal granules;
charging molten material metal into the die cavity through the inlet;
raising the metal injection unit after the starting metal has cooled and solidified to expose the as-cast material in the lower casting mold;
rotating the turntable and transporting the as-cast material to a position below a high-temperature press molding unit;
and a step of lowering a high-temperature press molding unit and subjecting the as-cast material to high-temperature press processing by a press die.
This metal forming method is characterized by the steps of: raising a metal injection unit and then lowering the needle pin; and crushing a shutter consisting of a mass of semi-molten metal granules formed near the boundary between the heated portion of the heat-resistant nozzle and the insulating spacer portion, thereby refilling the heated portion of the heat-resistant nozzle with material metal granules, and then proceeding to the forming of the next as-cast material.

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