JP3273433B2 - Injection molding method and injection molding machine for light alloy injection material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hopper containing a solid light alloy injection material, a cylinder barrel provided with an injection nozzle at the tip thereof, and a rotary and axial direction inside the cylinder barrel. Injection molding method for obtaining a molded product from a light alloy injection material by an injection molding machine having a screw provided so as to be driven in a direction, and a drive device for driving the screw in a rotational direction and an axial direction. And an injection molding machine used directly to carry out this method.

[0002]

2. Description of the Related Art An in-line screw type injection molding machine is well known without mentioning a document name, and is a cylinder barrel provided with a heater on an outer peripheral portion, and a screw which is rotated and driven in an axial direction in the cylinder barrel. And a hydraulic piston / cylinder mechanism for driving the screw in the axial direction, a hydraulic motor for driving in the rotational direction, and the like. Therefore, when the screw is driven to rotate by the hydraulic motor and the light alloy injection material is supplied to the cylinder barrel from the hopper, the solid light alloy injection material is kneaded by friction heat due to the rotation of the screw, shear heat insulation, heat applied from the heater, etc. -Melted and sent forward of the cylinder barrel and weighed. The measured light alloy injection material in the molten state is injected into a mold by supplying pressure oil to a hydraulic chamber of a hydraulic piston / cylinder mechanism and driving the screw in the axial direction. After cooling and solidification, the mold is opened to obtain a molded product.

[0003]

As described above, even with a conventional injection molding machine, a molded article can be obtained from a light alloy injection material by injection molding. However, while there are few problems during continuous injection molding, problems may occur particularly when molding is interrupted. That is,
Since light alloy injection materials are easily oxidized as seen in light alloys such as highly active magnesium alloys and aluminum alloys, the following problems arise when moldings are obtained by conventional injection molding machines. (1) In the screw supply section where the temperature is high and is easily oxidized, when the light alloy injection material is oxidized, the light alloy injection material solidifies in a lump, and in some cases, it becomes impossible to convey the light alloy injection material in the cylinder barrel. (2) The oxide formed on the surface of the solid light alloy injection material is mixed into the molded product, and deteriorates the quality of the molded product. (3) At the tip of the injection nozzle, the light alloy injection material is exposed to the atmosphere at a high temperature close to the melting point and is directly exposed to the atmosphere, so that a strong oxide is formed and the formed oxide becomes a plug, It may be impossible. (4) The molten light alloy injection material leaking from the tip of the injection nozzle may ignite and burn, damaging the heater, thermocouple, and the like wound around the outer periphery of the injection nozzle. SUMMARY OF THE INVENTION An object of the present invention is to provide an injection molding method of a light alloy injection material which solves the above-mentioned conventional disadvantages or problems, and an injection molding machine used for implementing the method.

[0004]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is directed to a hopper containing a solid light alloy injection material and an injection hopper at the tip of the hopper. Injection including a cylinder barrel provided with a nozzle, a screw provided so as to be rotated and driven in the cylinder barrel in the cylinder direction, and a drive device for driving the screw in the rotation direction and the axial direction. In an injection molding method for obtaining a molded article from a light alloy injection material by a molding machine, the interior of the hopper is kept under an inert gas atmosphere during a molding start preparation time, during a time when molding is interrupted for a predetermined time or more, and during a predetermined time after the molding is completed. The screw supply section below the hopper is made to have an inert gas atmosphere, and the tip of the injection nozzle is made to have an inert gas atmosphere. The present invention provides a hopper containing a solid light alloy injection material, a cylinder barrel provided with an injection nozzle at the tip thereof, and provided so as to be rotationally and axially driven within the cylinder barrel. When a molded product is obtained from a light alloy injection material by an injection molding machine including a screw that is being driven and a driving device that drives the screw in a rotational direction and an axial direction, the molding is interrupted for a predetermined time or more during a preparation start time of molding. During the time and for a predetermined time after the end of the molding, the inside of the hopper and the tip of the injection nozzle are made to have an inert gas atmosphere, and the inside of the hopper is also made to have an inert gas atmosphere during molding. The screw supply section of this embodiment is configured to be in an inert gas atmosphere even during molding. According to a third aspect of the present invention, there is provided a cylinder barrel provided with an external heating element, a screw provided in the cylinder barrel so as to be rotated and driven in the axial direction, A driving device that drives in the direction, a hopper for supplying a light alloy injection material to the cylinder barrel, and an injection nozzle provided inside the hopper and at a tip of the cylinder barrel are placed in an inert gas atmosphere. And an inert gas supply device for the injection molding machine, wherein the inert gas supply device,
A first gas supply line extending from the inert gas supply to the hopper; a second gas supply line also extending from the inert gas supply toward the injection nozzle;
And an inert gas replacement jig attached to the end of the gas supply pipe. The inert gas replacement jig has an opening through which an inert gas is released, and the opening is provided with the injection gas. A first position aligned with the nozzle and a second position retracted to a moldable position are provided so as to be movable, and the opening of the inert gas replacement jig is aligned with the injection nozzle and pressed. The part and the injection nozzle are configured to contact in an airtight state.

[0005]

For example, a heater is energized to heat a cylinder barrel, an injection nozzle and the like to a predetermined moldable temperature. During this heating time, the inside of the hopper is set to an inert gas atmosphere, so that the screw supply section below the hopper is also set to the inert gas atmosphere. Further, the tip of the injection nozzle is set to an inert gas atmosphere. When the temperature reaches a predetermined value, the solid light alloy injection material in the hopper is supplied to the cylinder barrel. Then, the screw is driven to rotate as conventionally known. Then, the light alloy injection material is kneaded and melted by frictional heat and shear heat generated when the screw rotates, and is measured in front of the cylinder barrel. The injection nozzle is opened from the inert gas atmosphere, and the measured light alloy injection material in the molten state is injected into the mold by driving the screw in the axial direction.
After cooling and solidification, remove the molded product. Hereinafter, the above weighing,
The injection operation is repeated to mold. Even when the molding is performed as described above, the inside of the hopper is continuously or intermittently brought into an inert gas atmosphere. By making the inside of the hopper an inert gas atmosphere, the screw supply section below the hopper is also made an inert gas atmosphere. Alternatively, when the molding operation is interrupted for a predetermined time or more, for example, for 10 minutes or more, the inside of the hopper is made to have an inert gas atmosphere, so that the screw supply section below the hopper is also made to have an inert gas atmosphere, and the tip of the injection nozzle is To an inert gas atmosphere. After the interruption for a predetermined time, the operation is resumed as described above. When the molding is completed, the light alloy injection material is discharged from the inside of the cylinder barrel so as not to remain, the heater is turned off, and the inside of the hopper and the tip of the injection nozzle are kept at a predetermined temperature, for example, 200 ° C. Inert gas atmosphere until below. Other inventions operate as described above, and also make the interior of the hopper an inert gas atmosphere during injection molding, and also make the screw supply section below the hopper an inert gas atmosphere.

[0006]

FIG. 1 shows an embodiment of an injection molding machine according to the present invention. The injection molding machine according to the present embodiment includes a cylinder barrel 1 having a conventionally known structure, a screw 15 provided in the cylinder barrel 1 so as to be able to be driven in the axial direction and the rotation direction, and a solid And a drive unit 30, 31 for driving the screw 15 in the axial direction and the rotational direction, and more specifically, an inert gas supply unit 40 described later.

The cylinder barrel 1 has a well-known structure, and an opening 2 is opened near the right rear end in the figure, and a supply port 24 of a hopper 20 is air-tightly connected to the opening 2. An injection nozzle 3 is provided at a front end of the cylinder barrel 1. As is well known, heaters 4, 4,... Which are individually and precisely temperature-controlled are provided on the outer peripheral portions of the cylinder barrel 1 and the injection nozzle 3.

A cylinder 5 ′ of a piston / cylinder device 5 is fixed to the cylinder barrel 1. A piston rod 7 extends from the piston 6 of the piston-cylinder device 5 to the left or forward in FIG. 1 and is fixed to a fixed platen 10 fixed to the injection table D. Therefore, when pressure oil is supplied to the hydraulic chamber 8 on the piston rod side of the piston / cylinder device 5, the cylinder barrel 1 and thus the injection nozzle 3 are driven in the direction of touching the fixed mold 11, and the oil is supplied to the oil chamber 9 on the piston head side. When you supply
It is driven in a direction away from the fixed mold 11.
As is well known, a fixed die 11 is mounted on the fixed platen 10, and a movable die 12 is mounted on a movable plate not shown in the drawing.

As is well known in the art, the screw 15 is divided into a solid transport section, that is, a screw supply section 16, a phase transition section, and a liquid transport section from the rear to the front end, and the rear end of the screw supply section 16 has a cylinder barrel. The screw shaft 17 extends outward from the first shaft 1. The screw shaft 17 is connected to an axial driving device 30 composed of a conventionally known piston / cylinder unit and the like, and a rotational driving device 31 composed of a hydraulic motor and the like. The hopper 20 includes a substantially funnel-shaped main body 21,
Lid 2 for hermetically sealing the upper opening of main body 21
And 2. And the slope 23 of the main body 21
Openings 25 and 26 for connecting a first gas supply pipe 43 to be described later are opened near the lower supply port 24.

The inert gas supply device 40 includes first and second cylinder-shaped pressure vessels 41 and 41 ′ containing argon gas, nitrogen gas and the like, and these pressure vessels 41 and 41 ′.
First and second gas supply pipes 43 and 46 extending toward the hopper 20 and the injection nozzle 3, respectively, and an inert gas replacement jig 5 for setting the tip of the injection nozzle 3 to an inert gas atmosphere.
0 and so on. From the first pressure vessel 41, a first gas supply line 43 extends toward the hopper 20, and two branch tubes 43 ', 43 "
26 are hermetically connected. The first gas supply pipe 43 has a pressure regulator 44 and a flow regulator 45.
Etc. are provided. From the second pressure vessel 41 ', the second
A gas supply line 46 extends toward the injection nozzle 3 and is connected to an inert gas replacement jig 50 via a flexible hose 47. The inert gas replacement jig 50 is provided to be vertically movable along the surface of the fixed platen 10 or to be detachable. A gas passage 51 is formed inside from the upper side toward the center, and the gas passage 51 has an opening 52 to the outside on the right surface in the drawing. The opening 52 has the same shape as the nozzle insertion hole of the locate ring normally provided in the solid board 10. Therefore, the injection nozzle 3 is connected to the opening 52 of the inert gas replacement jig 50.
When contacted, the inert gas does not leak to the outside.

Next, a method for injection-molding a light alloy injection material using the injection molding machine of the above embodiment will be described. Although a resin can be used as the injection material, a light alloy is used in this embodiment. The light alloy refers to a simple metal element having a melting point of 650 ° C. or less or an alloy based on these metals. Practical examples include, for example, aluminum, magnesium, zinc, tin, lead, bismuth, terbium, tellurium,
Cadmium, thallium, astatine, polonium, selenium, lithium, indium, sodium, potassium, rubidium, cesium, francium, gallium and the like, particularly aluminum, magnesium,
Preference is given to simple elements of lead, zinc, bismuth and tin and alloys based on these metals. All of these metal materials are metal elements or alloys that can be kneaded and melted by the injection molding machine of the above embodiment and injection molded.

During the preparation for molding start, the inert gas replacement jig 50 is slid by a driving device, for example, a hydraulic piston mechanism (not shown) so that the opening 52 is opened as shown in FIG. 3 to a first position axially aligned. Thus, pressure oil is supplied to the hydraulic chamber 8 on the piston rod side of the piston / cylinder device 5. Then, the injection nozzle 3 is connected to the opening 52 of the inert gas replacement jig 50.
Touch. Therefore, the main stopper 4 of the second pressure vessel 41 ′
Open 2 '. Then, the inert gas adjusted to a predetermined pressure by the pressure adjuster 48 is supplied from the gas passage 51 of the inert gas replacement jig 50 to the opening 5 through the second gas supply pipe 46.
2 is supplied. Thereby, the tip of the injection nozzle 3 is placed in an inert gas atmosphere. Also, the first pressure vessel 4
The first main plug 42 is also opened. Then, the inert gas, which is adjusted to the predetermined pressure by the pressure regulator 44 by the first gas supply pipe 43 and controlled to the predetermined flow rate by the flow regulator 45, flows from the branch pipes 43 'and 43 "through the hopper 20. Body 2
1 and the vicinity of the supply port 24. Thus, the inside of the main body 21 of the hopper 20, the vicinity of the supply port 24, and the screw supply unit 16 below the hopper 20 are placed in an inert gas atmosphere.

For example, a temperature sensor is attached to the cylinder barrel 1, and when the temperature sensor detects that the temperature has risen to a predetermined measurable temperature, the metering is started.
That is, the screw 15 is rotationally driven by the rotational direction driving device 31. Then, a solid light alloy injection material is supplied from the hopper 20 to the cylinder barrel 1. Then,
The light alloy injection material is supplied to the heaters 4, 4,
.., And frictional heat and shear heat generated when the screw 15 is driven to rotate, the melting gradually starts in the phase transition section, melts in the liquid transport section, and is measured in front of the cylinder barrel. As the measurement proceeds, the screw 15 is retracted by the pressure of the light alloy injection material in the molten state to be measured. In FIG. 1, the solid light alloy injection material is shown in multiple points, and the light alloy injection material in the molten state is shown in solid.

After measuring a predetermined amount, the second pressure vessel 41 '
Is closed. The pressurized oil is supplied to the oil chamber 9 on the piston head side of the piston / cylinder device 5 and the injection nozzle 3
Is separated from the inert gas replacement jig 50. Then, the inert gas replacement jig 50 is retracted to the second position which does not hinder the molding. Pressure oil is supplied to the hydraulic chamber 8 on the piston rod side of the piston / cylinder device 5 to fix the injection nozzle 3 to the fixed mold 11.
To touch. Thus, the screw 15 is driven at a high speed by the axial driving device 30. The measured light alloy injection material in the molten state is injected into the cavities of the molds 11 and 12 at high speed. After the injection is completed, the molded product is taken out after cooling and solidification. Meanwhile, weigh and inject as described above. Also when forming as described above, an inert gas is supplied to the main body 21 of the hopper 20 and the vicinity of the supply port 24.

Since the degree of oxidation increases when the operation is interrupted for a long period of time, for example, 10 minutes or more, the inert gas replacement jig 50 is moved to the first position shown in FIG. Is opened and the tip of the injection nozzle 3 is placed in an inert gas atmosphere. Also, the main body 2 of the hopper 20
The inert gas is also supplied to 1 and the vicinity of the supply port 24 as described above. The operation is restarted according to the above-described operation at the time of starting.
When the forming operation is completed, the screw 15 is driven to rotate so that the light alloy injection material in the cylinder barrel 1 is discharged so as to remain as little as possible. Then, the inert gas replacement jig 5
0 to the first position shown in the figure, and the tip of the injection nozzle 3 is placed in an inert gas atmosphere as described above.
The main body 21 of the hopper 20 and the vicinity of the supply port 24 are also placed in an inert gas atmosphere. The temperature sensor detects that the temperature of the cylinder barrel 1 is 1
When it is detected that the temperature has dropped to 00 to 200 ° C. or less, the main plugs 42 and 42 ′ are closed and the supply of the inert gas is stopped.

In the above embodiment, the inert gas replacement jig 50 is moved to the first position, and the injection nozzle 3 is driven by the piston / cylinder device 5 in the direction in which it comes into contact with the opening 52 of the inert gas replacement jig 50. However, after the inert gas replacement jig 50 is moved to the first position, the inert gas replacement jig 50 may be driven in a direction in which it comes into contact with the injection nozzle 3. In the description of the molding method using the above-described injection molding machine, there is no description about the control device itself, but it is described that molding is performed semi-automatically. However, molding is performed completely automatically or manually. Clearly what you can do.

[0017]

As described above, according to the present invention, a hopper containing a solid light alloy injection material, a cylinder barrel provided with an injection nozzle at the tip thereof, and In an injection molding method for obtaining a molded product from a light alloy injection material by an injection molding machine having a screw provided to be driven in rotation and an axial direction, and a driving device for driving the screw in the rotation direction and the axial direction. ,
During the molding start preparation time, during the time during which molding is interrupted for a predetermined time or more, and during the predetermined time after the end of molding, the interior of the hopper and the tip of the injection nozzle are set to an inert gas atmosphere, so that the light alloy injection material is In addition to not being oxidized, the light alloy injection material is not oxidized and solidified in the screw supply section below the hopper, making it impossible to transport during the molding cycle. Also, the quality of the molded product is not reduced. In addition, the injection nozzle is not clogged with an oxide plug, and the heater and thermocouple wound around the outer periphery of the injection nozzle are not damaged by ignition during oxidation, etc. In addition, the molding cycle can be started easily. Can be achieved. Further, according to another invention, the inside of the hopper is placed in an inert gas atmosphere during molding, so that the light alloy injection material is not oxidized in the hopper in addition to the above-mentioned effects, and, of course, Since the screw supply section is in an inert gas atmosphere, oxidation of light alloy injection materials such as highly active magnesium alloys and aluminum alloys is prevented, and the light alloy injection materials are smoothly transported in the cylinder barrel, and The effect is obtained that the deterioration of the quality of the molded article is suppressed.

[Brief description of the drawings]

FIG. 1 is a side view schematically showing a part of an injection molding machine according to an embodiment of the present invention in a cutaway manner.

[Explanation of symbols]

 Reference Signs List 1 cylinder barrel 3 injection nozzle 4 heater 15 screw 20 hopper 40 inert gas supply device 41 first pressure vessel 41 'second pressure vessel 43 first gas supply pipe 46 second gas supply pipe 50 inactive Gas replacement jig 52 opening

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B22D 17/20 B22D 17/00 B29C 45/18

Claims (3)

(57) [Claims] 1. A hopper (20) containing a solid light alloy injection material, a cylinder barrel (1) provided with an injection nozzle (3) at its tip, and the cylinder barrel (1). A screw (15) provided so as to be rotated and driven in an axial direction within the screw (1);
5) A driving device (30, 3) for driving the rotation direction and the axial direction.
1) obtaining a molded article from a light alloy injection material by an injection molding machine having the above-mentioned 1), wherein the hopper is used during a preparation start time, during a time when molding is interrupted for a predetermined time or more, and during a predetermined time after the completion of molding. (20)
Of the screw supply section (16) below the hopper (20) to an inert gas atmosphere, and the tip of the injection nozzle (3) to an inert gas atmosphere. An injection molding method of a light alloy injection material, characterized by comprising: 2. A hopper (20) containing a solid light alloy injection material, a cylinder barrel (1) provided with an injection nozzle (3) at the tip thereof, and the cylinder barrel (1). A screw (15) provided so as to be rotated and driven in an axial direction within the screw (1);
5) A driving device (30, 3) for driving the rotation direction and the axial direction.
1) obtaining a molded article from a light alloy injection material by using an injection molding machine provided with the above (1), during the preparation start time of the molding, during the time when the molding is interrupted for a predetermined time or more, and during the predetermined time after the completion of the molding,
The inside of the hopper (2) and the tip of the injection nozzle (3) are made to have an inert gas atmosphere, and the inside of the hopper (20) is also made to have an inert gas atmosphere during molding.
0) An injection molding method for a light alloy injection material, wherein the lower screw supply section (16) is kept in an inert gas atmosphere even during molding. 3. A cylinder barrel (1) provided with a heating body (4, 4,...) Outside thereof, and provided so as to be rotated and driven in the axial direction within the cylinder barrel (1). Screws (15) and driving devices (30, 31) for driving the screws (15) in the rotational direction and the axial direction
A hopper (20) for supplying a light alloy injection material to the cylinder barrel (1); and an injection nozzle (3) provided inside the hopper (20) and at a tip end of the cylinder barrel (1). ) In an inert gas atmosphere, the inert gas supply device (40) comprising: an inert gas supply source (41, 41). ) Extending from the inert gas supply source (41, 41 ') to the injection nozzle (3). A second gas supply pipe (46); and an inert gas replacement jig (50) attached to a tip of the second gas supply pipe (46). (50) has an opening (52) through which an inert gas is released. In both cases, the opening (5
2) is movably provided at a first position aligned with the injection nozzle (3) and a second position retracted to a moldable position, and the opening (52) of the inert gas replacement jig (50) is provided. )
The opening (52) and the injection nozzle (3) come into contact with each other in a gas-tight manner when they are pressed against the injection nozzle (3).