JP2004351892A - Injection molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injection molding machine capable of always supplying a material with high precision without exerting an effect on the metering precision of a material supply means even if vibration and an impact occur at the time of advance and retreat operation of an injection device. <P>SOLUTION: This injection molding machine is equipped with an extruder 11 for heating and melting a synthetic resin material to extrude the plasticized resin, a feeder 3 as a material means for supplying the synthetic resin material to the extruder 1 and the injection device 2 for metering the plasticized resin extruded from the extruder 1 to inject the same. The feeder 3 is supported on an independent frame 7 different from the extruder 1 and the injection device 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an injection molding device in which an extruder for plasticizing and extruding a synthetic resin material and an injection device are connected.
[0002]
[Prior art]
In an injection molding apparatus for molding a molded product by injecting a molten resin into an injection molding die, an extruder for plasticizing and extruding a synthetic resin material, and measuring and injecting the plasticized resin into the injection molding die. An accumulator device is provided between the injection device and the plasticized resin supplied from the extruder is temporarily stored in the accumulator device, and the plasticized resin stored in the cylinder of the accumulator device according to the injection timing of the injection device. There is known an online injection molding apparatus for supplying the pressure to an injection apparatus by a piston (for example, Patent Document 1).
[0003]
In this injection molding apparatus, the extruder is operated continuously, and when the plasticized resin is extruded from the extruder into the accumulator device, the piston in the cylinder of the accumulator device is pushed up by the resin discharge pressure, so that the accumulator is extruded from the extruder. It is supplied to the cylinder of the device. When the piston in the cylinder is pushed down by the driving device and the opening / closing valve of the cylinder is opened, the plasticized resin stored in the cylinder is supplied to the injection cylinder of the injection device.
[0004]
The injection plunger of the injection cylinder retreats and weighs the amount of plasticized resin required for one injection. Next, after the injection cylinder advances and the injection nozzle touches the injection molding die with the nozzle, the injection plunger in the injection cylinder advances and the opening / closing valve of the injection cylinder is opened. The plasticizing resin is injected into the mold, and one molding cycle is completed.
[0005]
[Patent Document 1]
Japanese Utility Model Publication No. 36-19372
[Problems to be solved by the invention]
By the way, in the extruder of the above-mentioned online injection molding apparatus, a feeder as a material supply means supplies a fixed amount of a synthetic resin material while weighing it using a weight-type or capacity-type sensor. However, this feeder is vulnerable to vibrations and shocks, and if vibrations or shocks are applied during supply, the measurement accuracy will vary.
[0007]
On the other hand, the online injection molding apparatus is used when a vibration occurs when clamping the fixed mold and the movable mold of the injection mold and when the injection cylinder moves forward and the injection nozzle touches the injection mold. There is a problem that mechanical vibration is generated, and this vibration is transmitted to the above-described feeder and affects the weighing accuracy of the feeder.
[0008]
The present invention has been made in view of the above circumstances, and has as its object to measure the feeder weighing accuracy even when vibration or impact occurs during the mold clamping operation of the injection molding die and the forward / backward operation of the injection device. An object of the present invention is to provide an injection molding apparatus capable of always supplying a high-precision material without affecting the injection molding apparatus.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides an extruder for extruding a plasticized resin by heating and melting a synthetic resin material, and a material supply means for supplying the synthetic resin material to the extruder. And an injection device for measuring and injecting the plasticized resin extruded from the extruder, wherein the material supply means is supported on an independent frame different from the extruder and the injection device. In the injection molding equipment.
[0010]
A second aspect of the present invention is characterized in that the material supply means of the first aspect moves in synchronization with the forward and backward movement of the injection device.
[0011]
A third aspect of the present invention is characterized in that the material supply part of the material supply means of the first aspect and the material receiving part of the extruder are connected by a member that absorbs vibration.
[0012]
A fourth aspect of the present invention is characterized in that the material supply means according to any one of the first to third aspects is a weight-type or capacity-type feeder, which supplies the synthetic resin material while measuring it.
[0013]
According to the configuration, the frame of the material supply unit and the frame of the injection device are formed as separate members, and the material supply unit and the injection device are provided separately from each other. Therefore, even if vibration or impact occurs during the mold clamping operation or the nozzle touch operation of the injection device, the vibration or impact is not transmitted to the material supply means, so that highly accurate metering can be performed.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0015]
FIG. 1 shows a first embodiment, and FIG. 1 is a schematic configuration diagram of an online injection molding apparatus. First, a schematic configuration will be described. An injection molding apparatus comprises an extruder 1 for plasticizing a synthetic resin material, and an injection apparatus provided in communication with the extruder 1 for measuring and injecting the extruded plasticized resin. 2 and a control section 4 including a feeder 3 as a material supply means for supplying a synthetic resin material to the extruder 1 and a control panel.
[0016]
The extruder 1 will be described. A parallel biaxial plasticizing screw 15 for kneading a synthetic resin material is provided inside a horizontal plasticizing cylinder 14. A material receiving portion 16 is provided at an upper portion on the base end side of the plasticizing cylinder 14. An outflow passage 18 is provided on the tip side of the plasticizing cylinder 14. A heater 19 is wound around the plasticizing cylinder 14 so that the synthetic resin material inside the plasticizing cylinder 14 is heated and melted.
[0017]
The feeder 3 which is provided further above the hopper 16 and supplies the synthetic resin material is for metering and supplying the material while metering, for example, a weight type or a capacity type such as a strain gauge type load cell. The feeder 3 includes a feeder cylinder 21 and a screw 22, and the screw 22 is rotated by a servomotor 23. A material supply hopper 24 for supplying a powdery synthetic resin material is provided at an upper portion on the base end side of the feeder cylinder 21, and a material discharge port 25 is provided at a lower portion on the tip side. The material discharge port 25 and the material receiving portion 16 are connected to each other by a flexible tube 17 as a vibration absorbing member having flexibility such as rubber, which is expandable and contractible in the axial direction. It is not transmitted to. Further, when the synthetic resin material is discharged from the material discharge port 25 by the rotation of the screw 22, the synthetic resin material falls down inside the flexible tube 17 and can be supplied to the material receiving portion 16 of the plasticizing cylinder 15.
[0018]
The feeder 3 is supported by a feeder base 5. The feeder base 5 is provided with rollers 6 so as to be movable in the direction of arrow A with respect to the feeder frame 7. The feeder frame 7 is provided with a hydraulic cylinder 8 for driving the feeder base 5 in the direction of arrow A.
[0019]
Rotational force is transmitted from the rotating shaft 27 of the inverter motor 26 via the gear box 28 to the plasticizing screw 15 having two parallel axes so that the plasticizing screw 15 rotates in the same direction at the same speed.
[0020]
The plasticizing screw 15 uses, for example, a feed portion of a general element, a kneading portion using a kneading disk, or the like, or an element having a gradually shortened lead from the base end side in the axial direction to the tip end side. It is composed of a compression section and is shorter than a screw of a general extruder. In addition, the plasticizing screw 15 having two parallel axes is continuously rotated in the same direction while contacting inside the plasticizing cylinder 14, and the synthetic resin material is kneaded while being heated by the heater 19.
[0021]
Therefore, the extruder 1 can knead and plasticize the supplied synthetic resin material while heating it even if it is a powder or a pulverized material. The conventional general plasticizing device has a low kneading capacity because it is a single-shaft plasticizing screw. For this reason, the powder-like synthetic resin material is heated and kneaded to granulate into pellets, and the pellet-like synthetic resin is supplied to the plasticizing apparatus. According to the twin-screw extruder 1 of the present apparatus, Since the powdery synthetic resin material can be plasticized, the granulation step can be omitted, and labor and energy can be saved.
[0022]
The outflow passage 18 of the extruder 1 communicates with the injection device 12 via a resin passage 30 provided in a connection block 29. A first opening / closing valve 31 formed of, for example, a rotary valve is provided in the middle of the resin passage 30.
[0023]
The injection device 2 includes a horizontal injection cylinder 32, and an injection plunger 33 for measuring and injecting a plasticized resin is provided inside the injection cylinder 32 so as to be able to advance and retreat in the axial direction. Around the injection cylinder 32, a heater 34 for heating the plasticized resin inside to maintain a molten state is wound. Further, a measuring chamber 35 is formed in a bore on the distal end side of the injection cylinder 32, and the measuring chamber 35 communicates with the resin passage 30. The measuring chamber 35 is connected to the injection nozzle 37 via a second opening / closing valve 36 formed of, for example, a rotary valve.
[0024]
At the rear end of the injection cylinder 32, a hydraulic cylinder 38 as an injection drive unit is provided. Inside the hydraulic cylinder 38, a piston 39 connected integrally with the injection plunger 33 is provided.
[0025]
The rear chamber 38a of the hydraulic cylinder 38 is connected to a tank 42 via a relief valve 40 and a switching valve 41. When the pressure in the rear chamber 32a exceeds the set pressure of the relief valve 40, the pressure oil in the rear chamber 38a is released to the tank 42, and the switching valve 41 is switched. The controlled pressure oil is supplied via a switching valve 41 and a check valve 44. The front chamber 38 b of the hydraulic cylinder 38 is connected to the switching valve 41.
[0026]
The injection cylinder 32 and the hydraulic cylinder 38 are supported by the injection device frame 9. That is, the injection device frame 9 is movably supported in the direction of arrow B by a linear guide 11 composed of a rail 10a and a guide member 10b movable with respect to the rail 10a. Furthermore, a hydraulic cylinder 12 for nozzle touch is provided between the injection device frame 9 and the injection cylinder 32.
[0027]
The feeder frame 7 and the injection device frame 9 are separate members, and are separately provided in the respective frames 7 and 9 that are independent of the feeder 3 and the injection device 2 including the extruder 1. Then, even if vibration or impact occurs during the mold clamping operation or the nozzle touch operation of the injection device 2, the vibration or impact is not transmitted to the feeder 3 supported by the feeder frame 7.
[0028]
The control unit 4 controls the servo motor 23, the inverter motor 26 of the extruder 1, and the switching valve 41 of the injection device 2, and controls the opening and closing of the first and second opening and closing valves 31, 36. .
[0029]
The injection nozzle 37 of the injection cylinder 32 is joined to the nozzle touch surface 51 of the injection molding die 50 at the time of injection. The injection molding die 50 is provided with a cavity 53 that communicates with the nozzle touch surface 51 via the resin passage 52. A cooling water passage 54 for circulating cooling water to cool the plasticized resin filled in the cavity 53 is provided around the cavity 53.
[0030]
Next, the operation of the online injection molding apparatus configured as described above will be described. The material supply hopper 24 and the feeder cylinder 21 of the feeder 3 contain a synthetic resin material, for example, a material in which powder such as polypropylene and a reinforcing material such as mica or a filling material is mixed. When the servo motor 23 is driven and the screw 22 rotates, the synthetic resin material in the feeder cylinder 21 is supplied from the material receiving portion 16 of the extruder 1 to the plasticizing cylinder 14 from the discharge path 25 via the flexible pipe 17. . The powder such as polypropylene and the reinforcing or filling material such as mica may be supplied by separate feeders.
[0031]
When the inverter motor 26 of the extruder 1 is driven, the rotation of the rotation shaft 27 of the inverter motor 26 is transmitted to the two-shaft plasticizing screw 15 via the gear box 28. The plasticizing screw 15 has a screw that functions as a feed unit, a kneading unit, and a compressing unit in the axial direction, and continuously rotates in the same direction while contacting inside the plasticizing cylinder 14, and is heated by the heater 19. The powdery synthetic resin material is uniformly heated, melted and kneaded to become a plasticized resin.
[0032]
The plasticized resin is introduced into the injection cylinder 32 through the resin passage 30 in which the first opening / closing valve 31 is open, and when the required amount (the amount of resin required for one injection) is measured, the hydraulic cylinder 12 Is driven, the entire injection device 2 is guided by the linear guide 11 and moves forward, and the injection nozzle 37 comes into contact with the nozzle touch surface 51 of the injection mold 50. Even if the injection device 2 vibrates due to the nozzle touch operation at this time, the feeder 3 and the injection device 2 including the extruder 1 are provided separately on the respective frames 7 and 9 independently of the feeder 3. And the extruder 1 are connected by the flexible tube 17 having flexibility, so that the vibration of the injection device 2 is not transmitted to the feeder 3. Therefore, the feeder 3 is not influenced by the vibration, can be metered with high metering accuracy, and can be plasticized in a more ideal state.
[0033]
Further, when the hydraulic cylinder 12 is driven to advance the entire injection device 2 while being guided by the linear guide 11, the hydraulic cylinder 8 for the feeder is also driven at the same time, and the entire feeder 3 is transferred via the feeder base 5 to the injection device 2. Can be followed. Therefore, the material supply can be continued by the feeder 3, and the cycle time can be reduced.
[0034]
Further, when a stop signal is input from the control unit 4 to the servo motor 23 and the inverter motor 26 of the extruder 11, the supply of the synthetic resin material, kneading and extrusion are stopped.
[0035]
In this case, when the extruder 11 is stopped, the inverter motor 26 is controlled so that the rotation speed of the plasticizing screw 15 is gradually lowered and stopped, whereby the plasticizing screw 15 and the gears in the gear box 28 are added. The torque can be reduced.
[0036]
Next, the first opening / closing valve 31 is closed and the second opening / closing valve 36 is opened by a signal from the control section 4, and the switching valve 41 is moved from the illustrated position to the left to switch to the right switching position. Pressure oil is supplied from the hydraulic pressure source 43 to the rear chamber 38a of the hydraulic cylinder 38 via the check valve 44, the injection plunger 33 is advanced, and the plasticized resin in the measuring chamber 35 is injected from the injection nozzle 37 to the injection molding die 50. And injection molding into the cavity 53.
[0037]
When the injection device 2 completes one injection, the servo motor 23 and the inverter motor 26 of the extruder 1 are restarted by a signal from the control unit 4 to supply the synthetic resin material and to knead and extrude the plasticized resin. The first opening / closing valve 31 is guided into the injection cylinder 32 through the resin passage 30 in the open state, and the amount of resin required for the next injection is measured. In this case, when the inverter motor 26 of the extruder 1 is restarted, the rotational speed of the plasticizing screw 15 is controlled to gradually increase toward the set value, so that the gears in the plasticizing screw 15 and the gear box 28 are controlled. Torque applied to the vehicle can be reduced.
[0038]
As described above, after the injection device 2 measures the amount of resin necessary for one injection, the injection plunger 33 is advanced by the injection cylinder 32 to inject the plasticized resin from the injection nozzle 37 into the injection mold 50. The extruder 1 performs an intermittent operation in conjunction with the intermittent operation of the injection device 2 to supply, knead and extrude the synthetic resin material. Therefore, the plasticized resin extruded from the extruder 1 can be set to the amount of resin necessary for the injection device 2 to perform one injection.
[0039]
In the above-described embodiment, the hydraulic cylinder 38 as the injection driving unit is employed. However, the injection plunger 33 may be moved forward and backward by a servomotor and a ball screw driven by the servomotor.
[0040]
Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying constituent elements in an implementation stage without departing from the scope of the invention. In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiments. For example, some components may be deleted from all the components shown in the embodiment. Further, components of different embodiments may be appropriately combined.
[0041]
【The invention's effect】
As described above, according to the present invention, the material supply means for supplying the synthetic resin material to the extruder is supported on an independent frame different from the extruder and the injection device, so that the mold for the injection molding die is provided. Even if vibration or impact occurs during the tightening operation or the forward / backward movement of the injection device, there is an effect that the precision of material supply can always be supplied without affecting the measuring accuracy of the material supply means.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an injection molding apparatus showing a first embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Extruder, 2 ... Injection apparatus, 3 ... Feeder (material supply means), 4 ... Control part, 7, 9 ... Frame, 8, 12 ... Hydraulic cylinder

Claims (4)

An extruder that extrudes a plasticized resin by heating and melting a synthetic resin material,
Material supply means for supplying a synthetic resin material to the extruder,
An injection device for measuring and injecting the plasticized resin extruded from the extruder,
An injection molding apparatus, wherein the material supply means is supported on an independent frame different from the extruder and the injection apparatus. 2. The injection molding apparatus according to claim 1, wherein the material supply means moves in synchronization with the forward and backward movement of the injection apparatus. The injection molding apparatus according to claim 1, wherein the material supply section of the material supply means and the material receiving section of the extruder are connected by a member that absorbs vibration. The injection molding apparatus according to any one of claims 1 to 3, wherein the material supply unit supplies the synthetic resin material while metering it using a weight-type or capacity-type feeder.

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