JP3621668B2 - Nozzle device for metal injection molding machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a metal injection molding machine that heats magnesium alloy or zinc alloy in a cylinder and injects a molten or semi-molten raw material, and a nozzle that connects a nozzle provided in front of the cylinder and a mold. It relates to the device.
[0002]
[Prior art]
Conventionally, as a general mold nozzle device, for example, one having a structure shown in FIG. 3 has been adopted.
[0003]
As shown in FIG. 3, a screw 3 for conveying and injecting a raw material is built in a cylinder 2 for melting (or semi-melting) and storing the raw material. A heater 1 is disposed outside the cylinder 2, and a nozzle 4 a is attached to the tip of the cylinder 2.
[0004]
The mold 5 includes a fixed mold 24 and a movable mold 25, both of which have a structure in which the insert 9 is incorporated in the mother mold 8, and the cavity 14 is formed by combining both inserts 9.
[0005]
A sprue bush 6 a that forms a sprue 12 that is an inlet for molten metal is incorporated in the fixed mold 24, and a runner 13 is formed between the sprue 12 and the cavity 14. A plug catcher bush 7a is incorporated in the movable die 25, and a recess 20a for receiving a solidified metal called a plug formed at the tip of the nozzle 4a is formed at the tip thereof. The movable mold 25 is provided with an ejector plate 10, and the ejector pin 11 is connected to the ejector plate 10.
[0006]
A support plate 22 having a heat insulating plate 23 on the surface is attached to the outside of the master die 8 of the fixed die 24 and the movable die 25, and concentrically with the nozzle 4a on the opposite side of the support plate 22 of the fixed die 24. A locate ring 26 is attached.
[0007]
As a nozzle device using a hot runner, one having a structure shown in FIG. 4 is usually employed.
[0008]
As shown in FIG. 4, a screw 3 for conveying and injecting a raw material is built in a cylinder 2 for melting (or semi-melting) and storing the raw material. A heater 1 is disposed outside the cylinder 2, and a nozzle 4 a is attached to the tip of the cylinder 2.
[0009]
The mold 5 includes a fixed mold 24 and a movable mold 25, both of which have a structure in which the insert 9 is incorporated in the mother mold 8, and the cavity 14 is formed by combining both inserts 9.
[0010]
A hot nozzle 15 is inserted into the fixed mold 24, and an induction coil 16 as an external heating device is attached to the outer periphery of the hot nozzle 15. A runner 13 is formed between the hot nozzle 15 and the cavity 14. The mother die 8 of the movable die 25 is provided with a recess 20b that receives a solidified metal called a plug formed at the tip of the hot nozzle 15. The movable mold 25 is provided with an ejector plate 10, and an ejector pin 11 is connected to the ejector plate 10.
[0011]
A support plate 22 having a heat insulating plate 23 on the surface is attached to the outside of the mother die 8 of the fixed die 24 and the movable die 25, and a locating ring 26 is attached to the side opposite to the mother die of the support plate 22 of the fixed die 24. It has been. The support plate 22 is provided with a heat insulating ring 17 a for preventing the heat of the hot nozzle 15 from escaping to the fixed mold 24.
[0012]
Next, the operation of a general mold nozzle device will be described.
[0013]
As shown in FIG. 3, the cylinder 1 and the nozzle 4a are heated by the heater 1, and the raw material is put into the cylinder 2 from the right side in the figure. The raw material thrown in by retreating the screw 3 while being rotated is conveyed to the front of the cylinder 2, and at that time, receives heat from the cylinder 2, enters a molten state, and is stored in front of the screw 3. On the other hand, the mold 5 including the fixed mold 24 and the movable mold 25 is heated by a heat medium (not shown).
[0014]
The movable mold 25 is advanced, the cylinder 2 is advanced with the mold 5 closed together with the fixed mold 24, the nozzle 4a is brought into contact with the mold 5, and the molten material is not leaked from this contact portion at a high pressure. Press. Next, the screw 3 is advanced at a high speed, and the raw material in a molten state passes through the runner 13 from the sprue 12 serving as a gate through the nozzle 4a and is filled into the cavity 14.
[0015]
After the molten raw material filled in the cavity 14 is cooled and solidified in the mold 5, the movable mold 25 is moved to open the mold 5. Thereafter, when the ejector plate 10 is pushed, the ejector pins 11 connected to the ejector plate 10 project the sprue 12, the runner 13 and the product, thereby releasing the mold.
[0016]
Next, the operation of the nozzle device using the hot runner will be described. In addition, about the operation | movement which abbreviate | omitted description, the operation | movement of the said general nozzle apparatus of a metal mold | die is used.
[0017]
As shown in FIG. 4, the nozzle 4 a is heated to the same temperature as the cylinder 2, is brought into contact with the hot nozzle 15 in advance, and waits in a state where it is pressed at a high pressure so that the molten material does not leak from the contact portion.
[0018]
By starting to move the movable die 25 to the fixed die 24 side, an electric signal is transmitted from the molding machine to a hot runner control device (not shown), and heating of the hot nozzle 15 is started. When the mold 5 is closed and the hot nozzle 15 reaches a predetermined temperature, an electric signal is transmitted from the control device of the hot runner to the molding machine. By performing the injection at a high speed, the raw material in a molten state passes through the runner 13 from the hot nozzle 15 and is filled into the cavity 14. After the filling is completed and an electric signal is transmitted from the molding machine to the control device of the hot runner, the heating of the hot nozzle 15 is stopped.
[0019]
After the molten raw material filled in the cavity 14 is cooled and solidified in the mold 5, the movable mold 25 is moved to open the mold 5. At that time, by pushing the ejector plate 10, the ejector pins 11 connected to the ejector plate 10 project the runner 13 and the product, thereby releasing the mold.
[0020]
[Problems to be solved by the invention]
The conventional general nozzle device is constructed as described above, so a large volume of unnecessary parts such as sprue, which is not related to the product, is generated every shot, so the production yield is low. It was one of the factors that increased costs. In addition, a nozzle device using a hot runner for the purpose of improving the material yield also needs to prepare an expensive hot nozzle and induction coil for each mold. It was limited to many products.
[0021]
The present invention has been made to solve the above-described problems, and reduces the unnecessary portion other than the molded product as much as possible, and prevents the cost of manufacturing the mold from becoming high. It aims at providing the nozzle apparatus for metal injection molding machines which can respond to all the products shape | molded by combining the nozzle apparatus of a metal mold | die with the advantage of the nozzle apparatus using a hot runner.
[0022]
[Means for Solving the Problems]
The present invention has solved the above problems as follows. That is, an extension nozzle that can be inserted into the mold is attached to the tip of a cylinder of the molding machine, and the temperature of this nozzle is controlled using an external heating device such as induction heating.
[0023]
A position-adjustable positioning plate is inserted into the movable mold side of the fixed mold, and the tip of the extension nozzle is inserted into a hole formed in the center of the positioning plate.
[0024]
The gap between them is sealed by the difference in thermal expansion between the tip of the extension nozzle and the positioning plate, and leakage of molten metal is prevented.
[0025]
A taper shape is provided on the outer periphery of the intermediate portion of the extension nozzle, and this is fitted with a taper shape provided on the mold side to form a taper contact portion, thereby receiving the touch force of the molding machine.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described based on examples with reference to the drawings.
[0027]
FIG. 1 is a configuration diagram illustrating a nozzle device using an extension nozzle according to an embodiment of the present invention.
[0028]
As shown in the figure, a screw 3 for conveying and injecting a raw material is built in a cylinder 2 for melting (or semi-melting) and storing the raw material. A heater 1 is disposed outside the cylinder 2, and an extension nozzle 4 is attached to the tip of the cylinder 2.
[0029]
The mold 5 includes a fixed mold 24 and a movable mold 25, both of which have a structure in which the insert 9 is incorporated in the mother mold 8, and the cavity 14 is formed by combining both inserts 9. A bush 6 into which the distal end side of the extension nozzle 4 is inserted is provided on the mother die 8 on the fixed die 24 side. An external heating device such as an induction coil 16 is provided on the outer periphery on the distal end side of the extension nozzle 4.
[0030]
The movable die 25 is provided with a plug catcher bush 7 having a recess 20 for receiving a solidified metal called a small plug formed at the tip of the extension nozzle 4. A runner 13 is formed between the recess 20 and the cavity 14. The movable mold 25 is provided with an ejector plate 10, and the ejector pin 11 is connected to the ejector plate 10.
[0031]
A support plate 22 having a heat insulating plate 23 on the surface is attached to the outside of the mother die 8 of the fixed die 24 and the movable die 25, and a locating ring 26 is attached to the side opposite to the mother die of the support plate 22 of the fixed die 24. A heat insulating ring 17 is attached to the support plate 22 so as not to let the heat of the extension nozzle 4 escape to the fixed mold 24.
[0032]
FIG. 2 is an enlarged view of the nozzle device of FIG.
[0033]
As shown in the figure, a positioning plate 18 is inserted on the movable mold side of the bush 6 and the outside thereof is fixed with screws or the like. A hole into which the distal end portion 27 of the extension nozzle 4 is inserted is formed in the center portion of the positioning plate 18. The positioning plate 18 is removed when the extension nozzle 4 is inserted into the mold, and is mounted after the extension nozzle 4 is inserted. This is to protect the tip 27 of the extension nozzle 4.
[0034]
A taper shape is provided in the intermediate portion of the extension nozzle 4 to receive the touch force of the molding machine, and a similar taper shape is also provided in the heat insulating ring 17. Form. The taper contact portion 19 also serves as a guide for the extension nozzle 4 for easily mounting the positioning plate 18.
[0035]
Next, the operation of the nozzle device using the extension nozzle according to the present invention will be described.
[0036]
First, the positioning plate 18 disposed on the fixed mold 24 is removed in advance, the cylinder 2 is advanced, and the extension nozzle 4 is inserted into the mold. At that time, the position adjustment function (not shown) installed in the cylinder 2 is adjusted so that the tip of the extension nozzle 4 is positioned at the center of the insertion port of the fixed die 24. Next, the positioning plate 18 is attached to the bush 6 and the mold 5 starts to be heated. In the meantime, the cylinder 1 is heated by the heater 1 arranged outside the cylinder 2, and the raw material is put into the cylinder 2 from the right side in the figure. The raw material thrown in as the screw 3 moves backward while rotating is conveyed to the front of the cylinder 1, and at that time, receives heat from the cylinder 2, enters a molten state, and is stored in front of the screw 3.
[0037]
The extension nozzle 4 stands by in a state where a touch force is generated between the extension nozzle 4 and the heat insulating ring 17. When the tip side of the extension nozzle 4 is heated to the base temperature that is the injection standby temperature, the outer peripheral gap of the tip portion 27 of the extension nozzle 4 is sealed due to the difference in thermal expansion with the positioning plate 18, and leaks from the tip of the extension nozzle 4. The molten raw material that exits is prevented from entering the bush 6.
[0038]
When molding is started from the state where the mold 5 is opened, a molding cycle start signal is transmitted from the molding machine to the temperature controller on the tip side of the extension nozzle 4, and the temperature on the tip side of the extension nozzle 4 is the base temperature which is the injection standby temperature. To a peak temperature which is an injection start temperature. When the mold 5 is closed and it is confirmed that the tip side of the extension nozzle 4 has reached the peak temperature, an injection start signal is transmitted from the temperature controller on the tip side of the extension nozzle 4 and the molding machine starts injection. When the injection is completed, for example, when the injection holding time expires, a signal is transmitted again from the molding machine to the temperature controller on the tip side of the extension nozzle 4 or is built in the temperature controller on the tip side of the extension nozzle 4. When the timer expires, the temperature on the tip side of the extension nozzle 4 shifts from the peak temperature to the base temperature. After the molten raw material filled in the cavity 14 is cooled and solidified in the mold, the movable mold 25 is moved to open the mold 5. Thereafter, when the ejector plate 10 is pushed, the ejector pin 11 connected to the ejector plate 10 is released by projecting the runner 13 and the product, and one molding cycle is completed.
[0039]
【The invention's effect】
According to the present invention, by extending the nozzle of the metal injection molding machine, it is possible to insert the nozzle into the mold, and it is no longer necessary to discharge the sprue portion that has been discarded so far. The cost can be reduced.
[0040]
In addition, the conventional nozzle device of a mold can be easily made into a nozzle device according to the present invention by improving the bushes of the sprue and the plug catcher, so that it corresponds to all products to be molded. Can do.
[0041]
In addition, in a conventional nozzle device using a hot runner, there is a connecting portion between the nozzle of the injection molding machine and the hot nozzle. However, the extension nozzle of the present invention is integrated so that there is no leakage of molten metal and safety. Is also greatly improved.
[Brief description of the drawings]
FIG. 1 is a configuration diagram illustrating a nozzle device using an extension nozzle according to an embodiment of the present invention.
FIG. 2 is an enlarged view of the nozzle device of FIG.
FIG. 3 is a configuration diagram showing a conventional general nozzle device of a mold.
FIG. 4 is a configuration diagram showing a nozzle device using a conventional hot runner.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Heater 2 Cylinder 3 Screw 4 Extension nozzle 4a Nozzle 5 Mold 6 Bush 6a Sprue bush 7, 7a Plug catcher bush 8 Mother die 9 Nest 10 Ejector plate 11 Ejector pin 12 Sprue 13 Runner 14 Cavity 15 Hot nozzle 16 Induction coil (external) Heating device)
17, 17a Heat insulation ring 18 Positioning plate 19 Tapered contact portion 20, 20a, 20b Recess 22 Support plate 23 Heat insulation plate 24 Fixed die 25 Movable die 26 Locate ring 27 Tip

Claims (3)

An extension nozzle (4) that is attached to the tip of the cylinder (2) of the molding machine and can be inserted into the mold, and a positioning plate (concentrically inserted with the extension nozzle (4) on the movable mold side of the fixed mold (24)) 18), and the tip (27) of the extension nozzle (4) is inserted into a hole formed in the positioning plate (18), and the tip of the extension nozzle (4) is caused by the difference in thermal expansion from the positioning plate (18). The outer peripheral gap of the portion (27) is sealed to prevent molten metal from entering, and the tapered portion provided on the outer periphery of the intermediate portion of the extension nozzle (4) is fitted to the tapered portion provided on the mold (5). A nozzle device for a metal injection molding machine characterized by receiving the touch force of the molding machine. The nozzle device for a metal injection molding machine according to claim 1, wherein the tip end side of the extension nozzle (4) is controlled to an injection standby temperature and an injection start temperature by an external heating device (16). The nozzle device for a metal injection molding machine according to claim 1 or 2, wherein the positioning plate (18) is detachable and can be adjusted in position.

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