JPH06246783A - Injection molding method and multi-material quality molded product - Google Patents

Abstract

PURPOSE:To obtain a molded product wherein a metal and a synthetic resin are strongly bonded without using an insert molding method by a method wherein a metal whose m.p. is specific temp. or lower is injected into a cavity of which the volume is smaller than the final volume in a molten state and the cavity is subsequently set to the final volume to inject a molten resin into the cavity. CONSTITUTION:First and second lower molds 14, 16 are fixed on the mold rotary plate 12 arranged on a fixed plate 10 and primary and secondary upper molds 22, 24 are fixed to the movable plate 20 opposed to the fixed plate 10 at the positions opposed to the lower molds 14, 16. Mold clamping is performed in such a state that the first lower mold 14 and the primary upper mold 12 are opposed to each other and a material with an m.p. of 450 deg.C or less selected from a metal such as zinc, tin or lead, a nonmetal and their compds. is injected in a molten state from a primary injection cylinder 30. Next, the molds are opened and a mold rotating plate is rotated by 180 deg. to close the molds and a molten resin is injected from a secondary injection cylinder 32 while the molten metal is injected from the primary injection cylinder 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding method and a multi-material molded product.

[0002]

2. Description of the Related Art As a conventional method for producing a multi-material molded product in which a synthetic resin portion and a metal portion are integrally joined, as shown in FIG. 7, a metal part which is produced in a predetermined shape in advance is injected. Insert into the opened mold of the molding machine (a in the same figure), and then inject the synthetic resin into the closed mold (b in the same figure) to integrate them, and open the mold to form multi-material molding There is a product which is designed to be taken out (c in the same figure). As a result, it is possible to manufacture a multi-material molded product in which the synthetic resin portion and the metal portion are firmly bonded to each other by the contracting force caused by the solidification of the molten resin.

[0003]

However, in the conventional injection molding method of a multi-material molded product in which the synthetic resin portion and the metal portion are integrally joined as described above, the equipment becomes complicated, so that the equipment cost is reduced. However, there is a problem that the multi-material molded product becomes expensive because it is bulky. That is, a device for manufacturing metal parts in advance, a robot machine for inserting the metal parts into the mold, and a drop prevention device for inserts depending on the type of injection molding machine (in the case of horizontal type) are required. Equipment costs will increase. The present invention aims to solve such problems.

[0004]

SUMMARY OF THE INVENTION The present invention involves injecting a first molten material, such as a metal, into a cavity with the cavity volume being less than the final volume, and then finalizing the cavity volume. The above problem is solved by injecting the molten resin into the cavity space portion other than the first material portion in a state in which the volume is set to a large value. That is, the injection molding method of the present invention,
The first injection step of injecting the first molten material into the cavity in a state where the cavity volume is smaller than the final volume, and the first injection process except for the first material portion in the state where the cavity volume is the final volume. A second injection step of injecting a second molten material into the cavity space portion, wherein the first molten material has a melting point of 450 ° C. or less, a metallic material, a nonmetallic material, and a compound thereof. And the second molten material is a synthetic resin. In addition, the multi-material molded product of the present invention has a final cavity volume with a metallic / non-metallic material portion having a melting point of 450 ° C. or less, which is injected into the cavity with the cavity volume being smaller than the final volume. It is composed of a synthetic resin portion which is integrated with the metal / non-metal material portion by being injected into the cavity space portion other than the metal / non-metal material portion in a state of having a large volume. Metal / non-metal materials include zinc, tin, lead, bismuth, terbium, tellurium, cadolinium, thallium, astatine, polonium, selenium, lithium, indium, iodine, sulfur, sodium, potassium, phosphorus, rubidium, cesium, francium, gallium,
And any of these compounds.

[0005]

The first molten material such as metal is injected into the cavity with the cavity volume smaller than the final volume, and then the first material with the cavity volume finalized. Molten resin is injected into the cavity space other than the above. As a result, a multi-material molded product in which the synthetic resin is firmly bonded to the first material can be molded without using an insert molding method or the like. Since the first material has a melting point of 450 ° C. or lower, it is not necessary to use a special heat-resistant material such as the injection cylinder at the portion where the molten material comes into contact. Can be used.

[0006]

【Example】

(First Embodiment) FIGS. 1 and 2 show a first embodiment in which the present invention is applied to a vertical injection molding machine. The fixed platen 10 is fixed to a fixed portion of the injection molding machine. A mold rotating plate 12 is rotatably arranged on the stationary platen 10. Mold rotating plate 1
A first lower mold 14 and a second lower mold 16 are fixed on the upper surface of the second mold 2, respectively. The movable platen 20 is arranged at a position facing the fixed platen 10. Movement of the movable platen 20 is guided by a plurality of tie bars 18 arranged with their axes parallel to each other, and a mold opening position shown in FIG. It is adapted to be driven between the mold closing position shown in FIG. A primary upper mold 22 and a secondary upper mold 24 are fixed to the movable plate 20 at positions facing the lower molds 14 and 16, respectively. A gear mechanism 26 is connected to the shaft of the mold rotating table 12. One end of the gear mechanism 26 is connected to the rotary motor 28. The rotation motor 28 is 18
It is said that the operation of rotating 0 degree and stopping at that position is repeated. As a result, in the mold open state, the first lower mold 14 faces the primary upper mold 22 and the second lower mold 1
6 is a position facing the secondary upper mold 24, and the mold rotating plate 12 is rotated 180 degrees from this position so that the first lower mold 14 faces the secondary upper mold 24. 2 The position where the lower mold 16 faces the primary-side upper mold 22 is alternately repeated. A primary injection cylinder 30 and a secondary injection cylinder 32 are arranged on the movable plate 20 side. From the primary injection cylinder 30, melting point 450 °
Zinc 34 (first material), which is the following metal, can be injected to the primary-side upper die 22 side, and the secondary-side injection cylinder 32 can also be injected.
From, it is possible to inject the molten resin to the secondary side upper mold 24 side.

Next, the operation of the first embodiment will be described.
At the start of the molding operation, as shown in FIG. 1A, the first lower mold 14 faces the primary upper mold 22, and the second lower mold 16 faces the secondary upper mold 24. Therefore, molten zinc 34 is injected into the cavities of the primary upper mold 22 and the first lower mold 14 from the primary injection cylinder 30 in the mold closed / clamped state. That is, the metal part of the molded product is molded. At this time, the molten resin is not injected from the secondary injection cylinder 32 (only when the molding operation is started). Next, the mold is opened, the rotary motor 28 is driven, and the mold rotating plate 12 is rotated 180 degrees via the gear mechanism 26, so that the first lower mold 14 is rotated as shown in FIG.
Faces the secondary upper mold 24, and the second lower mold 16 faces the primary upper mold 22. Then mold closing again
The mold is clamped, and the molten resin 36 is injected from the secondary injection cylinder 32 into the cavities of the secondary upper mold 24 and the first lower mold 14 as shown in FIG. The molten zinc 34 from the injection cylinder 30 is transferred to the primary side upper mold 2
2 and is injected into the cavity of the second lower mold 16. That is, the multi-material molded product 38 is molded in the secondary upper mold 24 and the first lower mold 14, and the metal part of the molded product is molded in the primary upper mold 22 and the second lower mold 16. Has been molded. Next, the mold is opened again, and the multi-material molded product 38 is taken out from the secondary upper mold 24 and the first lower mold 14 as shown in FIG. Next, the mold turntable 12 is 18
By rotating it by 0 degrees, the first lower mold 14 moves the primary upper mold 22 and the secondary upper mold 2 as shown in FIG.
4, and the second lower mold 16 faces the secondary upper mold 24. After that, although the combination of the upper mold and the lower mold is different, the multi-material molded product 38 can be obtained by repeating the steps of FIG. 2 (c) to FIG. It will be repeatedly molded. Generally, the material of the injection cylinder of a general-purpose injection molding apparatus is selected on the assumption that the melting point of the molten material is 500 ° C. or lower.
Above 0 ° C. (for example, in the case of aluminum having a melting point temperature of 660 ° C.), heat resistance becomes a problem, and it is necessary to use a heat resistant material. In the present invention, since the melting point temperature of the molten material is selected to be 450 ° C. or lower (the melting point temperature of zinc is 419 ° C.), it is not necessary to use a special heat resistant material for the injection molding device, and a general-purpose device It can be used as it is.

(Second Embodiment) Next, FIG. 3 shows a second embodiment of the present invention. This is a case of a horizontal injection molding machine, and a primary injection cylinder 42 and a secondary injection cylinder 44 are arranged on the fixed platen 40 side. A primary upper mold 52 and a secondary upper mold 54 are fixed to the stationary platen 40, respectively. A tie bar 60 is attached to the fixed platen 40. The tie bars 60 penetrate the four corners of the movable plate 46, so that the movement of the movable plate 46 is guided. The movable plate 46 has a mold clamping ram 5
0s are connected. A mold rotating plate 48 is arranged on the surface of the movable plate 46 facing the fixed plate. The mold clamping ram 50 is provided with a rotating device 60 so as to penetrate the movable plate 46. The rotating shaft of the rotating device 60 is attached to the mold rotating disk 48. A first lower mold 56 and a second lower mold 58 are fixed to the mold rotating disk 48. By driving the rotating device 60, the mold rotating disk 48 can be rotated.

Also in the second embodiment, a multi-material molded product is molded by operating in substantially the same manner as in the first embodiment.

(Third Embodiment) FIG. 4 shows a third embodiment of the present invention. In the third embodiment, only one set of dies 64 is provided, and a core 66 and a piston 68 are provided in the dies 64 so as to be axially movable. The rod 68 a of the piston 68 is connected to the core 66. The mold 64 has a first passage 64a and a second passage 64b formed therein. The first passage 64a of the mold 64 communicates with a primary injection cylinder (for zinc injection) not shown, and the second passage 64a.
b communicates with a secondary injection cylinder (for molten resin injection) not shown.

Next, the operation of the third embodiment will be described.
As shown in FIG. 4A, the hydraulic oil is supplied to the piston head side oil chamber of the piston 68, so that the piston 6
8 is moved in the rod extension direction, and the mold 6 is closed.
In FIG. 4, the core 66 is located at the cavity volume reduction position shown in the figure. Next, zinc in a molten state is injected into the cavity c1 of the mold 64 from the primary injection cylinder (not shown) through the first passage 64a. When the zinc solidifies, hydraulic oil is supplied to the piston rod side oil chamber of the piston 68, whereby the piston 68 is moved in the rod shortening direction, and the core 66 is moved to the cavity volume increasing position shown in FIG. Will be located in. Next, the molten resin is injected into the cavity c2 of the mold 64 from the secondary injection cylinder (not shown) through the second passage 64b. As a result, the multi-material molded product 70 is molded as shown in FIG. After a pressure-holding / cooling step, the mold is opened as shown in FIG. By repeating the above operation, the multi-material molded product 70 can be repeatedly molded. In this embodiment, the core 66 and the piston 68 can also serve as a product ejecting device.

(Fourth Embodiment) FIG. 5 shows a fourth embodiment of the present invention. In the fourth embodiment, a rotary shaft 72 orthogonal to the mold opening / closing direction of the horizontal injection molding machine is provided, and a mold rotary disk 74 is attached thereto.

The operation of the fourth embodiment is the same as that of the mold rotating plate 74.
It is almost the same as that of the second embodiment, except that the rotation axis of is different from that of the second embodiment.

(Fifth Embodiment) FIG. 6 shows a fifth embodiment of the present invention. In the fifth embodiment, two primary side injection cylinders 76 and 78 are provided, and different types of molten metal are respectively injected from these. Other configurations and operations are similar to those of the fourth embodiment.

In the description of the first embodiment described above,
Zinc was used as the low melting point material, but the melting point was 4
Any material of 50 ° or less may be used, such as tin, lead, bismuth, terbium, tellurium, cadolinium, thallium,
Astatine, polonium, selenium, lithium, indium, iodine, sulfur, sodium, potassium, phosphorus, rubidium, cesium, francium, gallium metal
Non-metals and compounds of these (including zinc) can be used. These materials defined as low melting point metal materials in the present invention have a maximum melting point of 450 ° C.
(Terbium and Tellurium), whose melting point is selected so that the heat resistance of the injection device does not matter.

[0016]

As described above, according to the present invention,
It is possible to mold a multi-material molded product using an inexpensive device without using a complicated molding method such as insert molding.

[Brief description of drawings]

FIG. 1 is a diagram illustrating an injection molding method of the present invention.

FIG. 2 is a diagram illustrating a molding process by a vertical injection molding machine.

FIG. 3 is a diagram illustrating a molding process by a horizontal injection molding machine.

FIG. 4 is a diagram illustrating a molding process of a multi-material molded product using a core retracting mold.

FIG. 5 is a diagram illustrating a molding process using a rotary disc type horizontal injection molding machine.

FIG. 6 is a diagram illustrating a molding process of a multi-material molded product using three kinds of materials.

FIG. 7 is a diagram illustrating a conventional molding process of a multi-material molded product made of metal and synthetic resin.

[Explanation of symbols]

 34 Zinc (low melting point metal material) 36 Synthetic resin 38 Multi-material molded product

Claims (3)

[Claims] 1. A first injection step of injecting a first molten material into a cavity with the cavity volume being smaller than the final volume, and a first injection step with the cavity volume being the final volume. A second injection step of injecting a second molten material into a cavity space portion other than the first material portion, wherein the first molten material has a melting point of 450 ° C. or less, a metallic material, a non-metallic material, and a compound thereof. , And the second molten material is a synthetic resin. 2. A metallic / non-metallic material portion having a melting point of 450 ° C. or less, which is injected into the cavity in a state where the cavity volume is smaller than the final volume, and the cavity volume is the final volume. A multi-material molded product made up of a synthetic resin part that is integrally formed with the metal / non-metal material part by being injected into the cavity space part other than the metal / non-metal material part in this state. 3. The metal / nonmetal material portion is zinc, tin,
Lead, bismuth, terbium, tellurium, cadolinium, thallium, astatine, polonium, selenium, lithium,
Indium, iodine, sulfur, sodium, potassium,
The multi-material molded product according to claim 2, which is selected from phosphorus, rubidium, cesium, francium, gallium, and compounds thereof.