JP2004291348A - Injection molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injection molding machine capable of miniaturizing an extruder because the kneading of a resin can be shared by the extruder and an in-line injection device and the total length of a screw can be reduced. <P>SOLUTION: The injection molding machine is equipped with a twin-screw extruder 11 equipped with two parallel plasticizing screws 16 for primarily kneading a synthetic resin material while heating the same and extruding the plasticized resin and the in-line injection device 13 equipped with a screw 55 for secondarily kneading the plasticized resin extruded from the twin-screw extruder 11 and metering/injecting the plasticized resin. <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 mold, a continuous plasticizing apparatus for plasticizing a synthetic resin material, and measuring and injecting the plasticized resin into the injection molding mold. The accumulator device is provided between the injection device and the accumulator device, and the plasticized resin supplied from the continuous plasticizing device is temporarily stored in the accumulator device, and the plasticized resin stored in the cylinder of the accumulator device is synchronized with the injection timing of the injection device. 2. Description of the Related Art A continuous plasticizing injection molding apparatus that supplies a plasticized resin to an injection apparatus by a piston is known (for example, see Patent Documents 1 to 7).
[0003]
[Patent Document 1]
Japanese Patent No. 3,007,920
[Patent Document 2]
Japanese Patent No. 3,062,629
[Patent Document 3]
Japanese Patent No. 3,077,048
[Patent Document 4]
Japanese Patent No. 3,146,368
[Patent Document 5]
Japanese Patent No. 3,256,914
[Patent Document 6]
Japanese Patent No. 3,281,995
[Patent Document 7]
Japanese Patent No. 3,303,213.
[0010]
In the continuous plasticizing injection molding device, when the continuous plasticizing device is continuously operated and the plasticized resin is extruded from the continuous plasticizing device to the accumulator device, the piston in the cylinder of the accumulator device is pushed up by the resin discharge pressure. Thereby, it is supplied to the cylinder of the accumulator device from the continuous plasticizing 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.
[0011]
When the injection plunger of the injection cylinder retreats and the amount of plasticized resin required for one injection is measured, the opening and closing valve of the cylinder closes, the injection plunger advances, and when the opening and closing valve of the injection cylinder opens, the injection cylinder opens. , The plasticized resin is injected into the injection molding die, and one molding cycle is completed.
[0012]
[Problems to be solved by the invention]
By the way, the continuous plasticizing apparatus of the continuous plasticizing type injection molding apparatus described above operates continuously, whereas the injection apparatus operates intermittently. Therefore, the plasticized resin is supplied from the continuous plasticizing device to the accumulator device and accumulated therein during the injection operation of the injection device. That is, when the open / close valve provided in the cylinder of the accumulator device is closed and the piston is pushed up by the plasticizing resin, the plasticizing resin is again supplied from the continuous plasticizing device into the cylinder of the accumulator device and accumulated.
[0013]
The continuous plasticizing device functions as an extruder for extruding the plasticized resin by heating and melting the synthetic resin material by heating and melting, but the overall length of the screw is long and the entire extruder is large. . In addition, during the injection operation of injecting the plasticized resin by the injection device, since the pressure on the injection side is directly transmitted to the plasticization side, that is, the extruder side, a backflow prevention mechanism between the plasticization device and the injection device, for example, It is necessary to provide a check valve, a rotary valve and the like, and there is a problem that the structure becomes complicated.
[0014]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an injection molding apparatus capable of simplifying the configuration of the entire apparatus.
[0015]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides an extruder for primary kneading a synthetic resin material while heating and extruding a plasticized resin, and a plasticized resin extruded from the extruder. And an in-line injection device for measuring and injecting the plasticized resin.
[0016]
A second aspect of the present invention is characterized in that the screw of the extruder according to the first aspect is axially divided into screw elements having different shapes that function at least as a feed section, a kneading section, and a compression section.
[0017]
A third aspect of the present invention is characterized in that the screw of the in-line type injection device according to the first aspect has a screw shape having a function of rectifying the plasticized resin.
[0018]
A fourth aspect of the present invention provides a twin-screw extruder provided with a parallel twin-screw for extruding plasticized resin by primary kneading while heating a synthetic resin material, and a plasticized resin extruded from the twin-screw extruder. An injection molding device, comprising: a screw for secondary kneading; and an in-line injection device for measuring and injecting the plasticized resin.
[0019]
Claim 5 comprises a continuous plasticizing device for plasticizing the synthetic resin material, a cylinder communicating with an outflow passage of the continuous plasticizing device, and a piston provided in the cylinder, and supplied from the continuous plasticizing device. An accumulator device for temporarily storing the obtained plasticized resin, and an inline injection device for measuring and injecting the plasticized resin supplied from the accumulator device, wherein the inline injection device includes an injection cylinder, and the injection cylinder. A continuous plasticizing type injection molding apparatus characterized by comprising a screw provided therein for kneading a plasticized resin, and a drive source for rotationally driving the screw.
[0020]
According to the above configuration, a screw for secondary kneading the plasticized resin extruded from the extruder is provided, and an in-line injection device for measuring and injecting the plasticized resin is provided, thereby reducing the kneading capacity on the extruder side. In other words, a single axis may be used, and the configuration of the entire apparatus can be simplified.
[0021]
In addition, the extruder is first kneaded while heating the synthetic resin material by a twin-screw extruder equipped with a parallel twin-screw, and the plasticized resin is extruded into an in-line injection device, and plasticized by the screw of the in-line injection device. By secondary kneading the resin, the kneading of the resin can be shared between the twin-screw extruder and the in-line injection device, and the overall length of the screw can be shortened, so that the twin-screw extruder can be downsized.
[0022]
By using an in-line injection device, during the injection operation of injecting the plasticized resin, since the pressure on the injection side is not transmitted to the plasticization side, that is, the extruder side, a backflow prevention mechanism is provided between the plasticization device and the injection device. This eliminates the necessity and simplifies the structure.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0024]
1 and 2 show a first embodiment, and FIG. 1 is a schematic configuration diagram of a continuous plasticizing type injection molding apparatus. First, a schematic configuration will be described. A continuous plasticizing type injection molding apparatus is provided with a twin-screw extruder 11 as a continuous plasticizing apparatus for plasticizing a synthetic resin material and communicating with the twin-screw extruder 11. An accumulator device 12 for temporarily storing the supplied plasticized resin, and an in-line injection device 13 for measuring and injecting the plasticized resin supplied from the accumulator device 12, and a control unit 14 including a control panel. ing.
[0025]
Next, the twin screw extruder 11 will be described. A parallel twin screw plasticizing screw 16 for primary kneading is provided inside a horizontal plasticizing cylinder 15. A supply port 18 having a hopper 17 is provided at an upper portion on the base end side of the plasticizing cylinder 15. An outflow passage 19 is provided on the tip side of the plasticizing cylinder 15. Further, a heater 15a is wound around the plasticizing cylinder 15, so that the synthetic resin material inside the plasticizing cylinder 15 is heated and melted.
[0026]
Further above the hopper 17, a feeder 20 for supplying a synthetic resin material is provided. The feeder 20 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 rotation of the screw 22 allows the synthetic resin material to be supplied from the material discharge port 25 to the hopper 17 of the plasticizing cylinder 15.
[0027]
Rotational force is transmitted from the rotating shaft 27 of the inverter motor 26 via the gear box 28 to the plasticizing screw 16 having two parallel axes so that the plasticizing screw 16 rotates in the same direction at the same speed.
[0028]
As shown in FIG. 2, the plasticizing screw 16 includes, for example, a feed portion 16a of a general element, a kneading portion 16b using a kneading disc, and a lead, from the base end side in the axial direction to the tip end side. The compression section 16c uses an element that is gradually shortened, and is shorter than a screw of a general extruder. In addition, the plasticizing screw 16 having two parallel axes is continuously rotated in the same direction while contacting inside the plasticizing cylinder 15, and the synthetic resin material is kneaded while being heated by the heater 15a.
[0029]
Therefore, the twin-screw extruder 11 can knead and plasticize the supplied synthetic resin material while heating it even if it is a powder or 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-shaped synthetic resin material is heated and kneaded to granulate into pellets, and the pellet-shaped synthetic resin is supplied to the plasticizer. According to the twin-screw extruder 11 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.
[0030]
Next, the accumulator device 11 will be described. A vertical cylinder 30 is provided, and a piston 31 is provided in an accumulator chamber 29 inside the cylinder 30 so as to be vertically movable. A heater 30a is wound around the cylinder 30 to heat the plasticized resin inside to keep the plasticized state.
[0031]
An opening is provided in the side wall of the cylinder 30, and the opening communicates with the outflow passage 19 of the plasticizing cylinder 15. Further, a resin outflow passage 32 is provided at a lower end portion of the cylinder 30, and a first opening / closing valve 33 formed of a rotary valve is provided in the resin outflow passage 32.
[0032]
The main body 34 of the piston 31 is formed to have an outer diameter that is in close contact with the inner peripheral surface of the cylinder 30, and the lower end of the main body 34 is formed with an inclined surface 34a so that the outflow path 19 side is high and the opposite side is low. ing. Further, a protruding small-diameter portion 35 protruding downward from the inclined surface 34a and having a diameter smaller than the inner diameter of the cylinder 30 is provided. Therefore, when the piston 31 is at the lower limit position, the highest position of the inclined surface 34 a is located above the outflow passage 19, and an annular flow passage 36 is formed between the small projecting portion 35 and the inner peripheral surface of the cylinder 30. It has become so.
[0033]
The piston rod 31a of the piston 31 projects upward through a through hole 30b provided at the upper end of the cylinder 30, and the piston rod 31a is connected to a plunger 37 of a hydraulic cylinder 38 as a driving device. The upper chamber 38a of the hydraulic cylinder 38 is connected to a tank 41 via a first relief valve 39 and a first switching valve 40. When the pressure in the upper chamber 38a exceeds the set pressure P1 of the first relief valve 39, the pressure oil in the upper chamber 38a is released to the tank 41, and the first switching valve 40 is switched, so that the first switching valve 40 is switched. Pressure oil controlled to a predetermined pressure and flow rate is supplied from a hydraulic pressure source 42 via a first switching valve 40 and a check valve 43. The lower chamber 38 b of the hydraulic cylinder 38 is connected to the first switching valve 40.
[0034]
Next, the in-line injection device 13 will be described. A screw 55 that has a function of rectifying the plasticized resin and performs secondary kneading is provided inside the horizontal injection cylinder 54 so as to be able to advance and retreat in the axial direction.
[0035]
Around the injection cylinder 54, a heater 53 that heats the internal plasticized resin to maintain a molten state is wound. Further, a measuring chamber 56 is formed in the inner cavity on the distal end side of the injection cylinder 54, and the base end side of the injection cylinder 54 communicates with the resin outflow passage 32 provided in the cylinder 30 of the accumulator device 11. The measuring chamber 56 is connected to the injection nozzle 58 via a second opening / closing valve 57 composed of a rotary valve.
[0036]
A through hole 59 is provided at the rear end of the injection cylinder 54, and the screw 55 is connected to a plunger 62 of a hydraulic cylinder 61 as an injection drive unit via a rod 60 that penetrates the through hole 59.
[0037]
The rear chamber 61a of the hydraulic cylinder 61 is connected to a tank 65 via a second relief valve 63 and a second switching valve 64. When the pressure in the rear chamber 61a exceeds the set pressure P2 of the second relief valve 63, the pressure oil in the rear chamber 61a is released to the tank 65, and the second switching valve 64 is switched, so that the second switching valve 64 is switched. Pressure oil controlled to a predetermined pressure and flow rate is supplied from a hydraulic source 66 via a second switching valve 64 and a check valve 67. The front chamber 61 b of the hydraulic cylinder 61 is connected to a first switching valve 64.
[0038]
The set pressures P1, P2 of the first and second relief valves 39, 63 plasticize the pressure of the plasticized resin extruded from the outlet 19 of the twin-screw extruder 11, that is, the back pressure of the twin-screw extruder 11. The piston 31 is set by the discharge pressure of the plasticized resin with the extrusion of the plasticized resin into the accumulator chamber 29 of the accumulator device 12 while maintaining the back pressure at a desired value while maintaining the back pressure at a desired value. It can be pushed up.
[0039]
The screw 55 of the in-line injection device 13 is driven to rotate by a rotation driving unit 61a. That is, as shown in FIG. 3, the rod 60 of the screw 55 is divided into a screw side rod 75a and a plunger side rod 75b. The proximal end of the screw-side rod 75a is rotatably supported by a bearing 76a provided on a guide member 76. A spline 77 is provided on the piston rod 75a. A driven pulley 78 rotatably supported by a bearing 78b supported by a bearing support member 78a is spline-engaged with the spline 77.
[0040]
The guide member 76 is provided with a guide hole 76b, and a guide bar 79 attached to the hydraulic cylinder 78 is relatively movably inserted into the guide hole 76b. That is, the guide member 76 can move forward and backward using the guide bar 79 as a guide.
[0041]
Further, a servo motor 80 with an encoder as a drive source is fixed to a frame or the like. A drive pulley 81 is fitted on the rotation shaft of the servo motor 80. A timing belt 82 is stretched between the driving pulley 81 and the driven pulley 78 to transmit the rotation of the servomotor 80 to the piston rod 75.
[0042]
The servo motor 23 of the feeder 20, the inverter motor 26 of the twin-screw extruder 11, the first and second opening / closing valves 33 and 57, and the servo motor 80 are controlled by the control unit 14.
[0043]
The injection nozzle 58 of the injection cylinder 54 is joined to the nozzle touch surface 71 of the injection mold 70 at the time of injection. The injection molding die 70 is provided with a cavity 73 communicating with the nozzle touch surface 71 via the resin passage 72. Further, a cooling water passage 74 for circulating cooling water to cool the plasticized resin filled in the cavity 73 is provided around the cavity 73.
[0044]
Next, the operation of the continuous plasticizing injection molding apparatus configured as described above will be described. The material supply hopper 24 and the feeder cylinder 21 of the feeder 20 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 falls from the discharge path 25 to the hopper 17 of the twin-screw extruder 11 and is supplied to the plasticizing cylinder 15 through the supply port 18. Is done. The powder such as polypropylene and the reinforcing or filling material such as mica may be supplied by separate feeders.
[0045]
The inverter motor 26 of the twin-screw extruder 11 is continuously driven, and the rotation of the rotary shaft 27 of the inverter motor 26 is transmitted to the biaxial plasticizing screw 16 via the gear box 28. The plasticizing screw 16 has a screw that functions as a feed section 16a, a kneading section 16b, and a compression section 16c in the axial direction, and continuously rotates in the same direction while contacting inside the plasticizing cylinder 15, and is further heated by the heater 15a. Therefore, the powdery synthetic resin material is uniformly heated, melted, and primary kneaded to become a plasticized resin.
[0046]
The first opening / closing valve 33 of the cylinder 30 is closed, and the plasticized resin is accumulated in the accumulator device 12 with the first switching valve 40 in the illustrated state. Therefore, when the plasticized resin is extruded from the outflow passage 19 of the plasticizing cylinder 15 and flows out to the cylinder 30 of the accumulator device 12, the plasticized resin pushes up the piston 31.
[0047]
At this time, the rise of the piston 31 enlarges the accumulator chamber 29 while being controlled by the set pressure of the first relief valve 39, and the plasticized resin is accumulated therein.
[0048]
Next, after the first opening / closing valve 33 is opened, the first switching valve 40 is moved to the left from the position shown in the figure to switch to the right switching position. A flow rate of pressure oil is supplied to the upper chamber 38a of the hydraulic cylinder 38 via the check valve 43. Thereby, the piston 31 descends at a predetermined speed. At this time, the rear chamber 61a of the hydraulic cylinder 61 is connected to the tank 65 via the second relief valve 63 and the second switching valve 64, and the second relief valve 63 is connected to the first relief valve 39 as described above. Since the set pressure P2 is set so as to maintain the back pressure of the outflow passage 19 at a predetermined value, the plasticized resin in the accumulator chamber 29 prevents the supply of the plasticized resin from the outflow passage 19. Instead, it flows into the injection cylinder 54 from the lower outflow passage 32 through the first opening / closing valve 33.
[0049]
The piston 31 of the accumulator device 12 descends to the extrusion limit position and is held at this position. At this time, they are joined from the accumulator chamber 29 and the twin-screw extruder 11 and sent to the injection cylinder 54.
[0050]
When the piston 31 is located at the extrusion limit position, an annular flow path 36 is formed in the accumulator chamber 29, so that the plasticized resin continuously extruded from the outflow path 19 can be injected into the injection cylinder 54 through the annular flow path 36. Sent without stagnation.
[0051]
At this time, since the screw 55 of the in-line injection device 13 is rotated in the injection cylinder 54 by the rotation transmitted from the servo motor 80 via the screw-side rod 75a, the plasticized resin supplied from the accumulator device 12 is removed. Secondary kneading. Since the screw-side rod 75a and the plunger-side rod 75b are divided into two parts, no rotational force is transmitted to the plunger-side rod 75b.
[0052]
In this way, when a predetermined amount of the plasticized resin necessary for one injection is completely kneaded and supplied to the measuring chamber 56 of the injection cylinder 54 and measured, the first opening / closing valve 33 is closed and the first opening / closing valve 33 is closed. The second open / close valve 57 is opened, the second switching valve 64 is moved to the left from the position shown in the figure to switch to the right switching position, and the hydraulic cylinder 61 is switched from the second hydraulic source 66 via the check valve 67. Pressure oil is supplied to the rear chamber 61a, the screw 55 is advanced, and the plasticized resin in the measuring chamber 56 is injected from the injection nozzle 58 into the cavity 73 of the injection mold 70 to perform molding.
[0053]
At the same time as closing the first opening / closing valve 33, the first switching valve 40 is switched to the neutral position shown in the figure, and the plasticized resin continuously fed from the outflow passage 19 is again accumulated in the accumulator chamber 29.
[0054]
As described above, while the twin-screw extruder 11 operates continuously, the in-line injection device 13 operates intermittently to inject the plasticized resin into the injection mold 70 to perform molding. The plasticized resin continuously fed from the extruder 11 is temporarily stored in the accumulator device 12, and the plasticized resin flows from the accumulator device 12 into the inline injection device 13 in accordance with the measurement timing of the inline injection device 13. it can.
[0055]
In the above embodiment, the twin-screw extruder 11 is connected to the in-line injection device 13 via the accumulator device 12, but the timing of extruding the plasticized resin from the twin-screw extruder 11 and the in-line injection device 13 By adjusting the timing of receiving the resin, the resin can be directly supplied from the twin-screw extruder 11 to the in-line injection device 13, and can be measured and injected by the in-line injection device 13, and the accumulator device 13 can be omitted. That is, the present invention is not limited to a continuous plasticizing injection molding apparatus.
[0056]
Although the twin-screw extruder 11 is used as the extruder, the kneading capacity on the extruder side can be reduced by employing the in-line injection device 13, and a single-screw extruder may be used.
[0057]
Further, although the rotation of the servomotor 80 is transmitted to the rod 60 by a pulley and a belt as the rotation drive unit 61a, the power may be transmitted by a sprocket and a chain or a gear mechanism instead of the pulley and the belt.
[0058]
In addition, the hydraulic cylinders 38 and 61 are used for the accumulator device 12 and the in-line injection device 13 and are driven by hydraulic pressure. However, as the driving device, the rotary motion is converted into linear motion by a servomotor and a ball screw / nut, and the drive is performed. You may make it.
[0059]
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.
[0060]
【The invention's effect】
As described above, according to the present invention, the primary kneading is performed while the synthetic resin material is heated by the extruder, and the plasticized resin is extruded to the in-line injection device, thereby reducing the kneading capacity on the extruder side. It is also possible to simplify the configuration as a single-screw extruder.
[0061]
In addition, the primary kneading is performed while heating the synthetic resin material with a twin-screw extruder, the plasticized resin is extruded into an in-line type injection device, and the plasticized resin is secondarily kneaded with a screw of the in-line type injection device. The kneading can be shared by the twin-screw extruder and the in-line injection device, and the overall length of the screw can be shortened, so that the twin-screw extruder can be downsized.
[0062]
By using an in-line injection device, during the injection operation of injecting the plasticized resin, since the pressure on the injection side is not transmitted to the plasticization side, that is, the extruder side, a backflow prevention mechanism is provided between the plasticization device and the injection device. This eliminates the necessity and has the effect of simplifying the structure.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a continuous plasticization type injection molding apparatus showing a first embodiment of the present invention.
FIG. 2 shows the same embodiment, and is a side view of a plasticizing screw.
FIG. 3 is a longitudinal sectional side view of the rotation drive unit, showing the embodiment.
[Explanation of symbols]
11 ... twin screw extruder, 12 ... accumulator device, 13 ... in-line injection device, 14 ... control unit, 29 ... accumulator chamber, 30 ... cylinder, 31 ... piston, 54 ... injection cylinder, 55 ... screw, 80 ... servo motor ( Drive source)

Claims (5)

An extruder that extrudes plasticized resin by primary kneading while heating the synthetic resin material,
An injection molding apparatus comprising: a screw for secondary kneading the plasticized resin extruded from the extruder; and an in-line type injection device for measuring and injecting the plasticized resin. An injection molding apparatus wherein the screw of the extruder is axially divided into screw elements having different shapes that function as at least a feed section, a kneading section, and a compression section. 2. The injection molding apparatus according to claim 1, wherein the screw of the in-line type injection apparatus has a screw shape having a function of rectifying plasticized resin. A twin-screw extruder equipped with a parallel twin-screw that extrudes plasticized resin by primary kneading while heating a synthetic resin material;
An injection molding apparatus comprising: a screw for secondary kneading the plasticized resin extruded from the twin-screw extruder; and an in-line injection device for measuring and injecting the plasticized resin. A continuous plasticizer for plasticizing the synthetic resin material,
An accumulator device comprising a cylinder communicating with the outflow passage of the continuous plasticizing device and a piston provided in the cylinder, and temporarily storing the plasticized resin supplied from the continuous plasticizing device,
An in-line injection device for measuring and injecting the plasticized resin supplied from the accumulator device,
The in-line injection device is a continuous plasticization type injection molding device, comprising: an injection cylinder; a screw provided in the injection cylinder for kneading a plasticized resin; and a drive source for driving the screw to rotate. .

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