JP7370886B2 - Injection molding machines and injection molding systems - Google Patents

Description

The present invention relates to an injection molding machine and an injection molding system that automatically supply resin.

An example of a conventional injection molding machine is disclosed in Patent Document 1. The injection molding machine of Patent Document 1 is connected to a suction type replenishment device that transfers resin, and replenishes resin to the hopper every time injection is performed, so that the remaining amount of resin in the hopper is the same for each injection. .

In the injection molding machine disclosed in Patent Document 1, a position detection device detects the retraction limit position of the screw in a metering process, and a suction type replenishment device is activated based on a control signal output from the position detection device. The timing for activating the suction type replenishment device is not limited to when it is detected that the screw has reached the retraction limit position, but may also be when the metering process is started and the screw has retracted to a certain position.

Japanese Patent Application Publication No. 3-268916

However, in the injection molding machine of Patent Document 1, resin may be supplied to the hopper in a state where the screw is not stopped, such as when the screw is rotating or moving back and forth. Therefore, the air flow generated when resin is supplied causes the resin to fly up in the hopper, and the load applied to the resin when it is supplied to the heating cylinder suddenly changes, resulting in changes in the plasticized state of the resin, such as density and degree of kneading. There was a risk that variations would occur.

Therefore, an object of the present invention is to provide an injection molding machine and an injection molding system that can suppress variations in the state of resin.

In order to achieve the above object, an injection molding machine according to one aspect of the present invention includes a heating cylinder, a hopper for storing resin to be supplied to the heating cylinder, and a screw housed in the heating cylinder. The machine is characterized in that the resin is supplied into the hopper only when the screw is stopped.

According to the present invention, resin is supplied into the hopper only when the screw housed in the heating cylinder is stopped. With this arrangement, although there is a risk that the resin will fly up in the hopper as the resin is supplied, since the screw is stopped, the resin will not be supplied to the heating cylinder. After the flying resin falls, the screw is operated to supply the resin to the heating cylinder. Therefore, when the resin is supplied to the heating cylinder, the load applied to the resin can be prevented from changing suddenly, and variations in the state of the resin can be suppressed.

According to the present invention, variations in the state of the resin can be suppressed.

1 is a diagram showing a schematic configuration of an injection molding system according to an embodiment of the present invention. 2 is a functional block diagram of the injection molding system of FIG. 1. FIG. FIG. 2 is an enlarged cross-sectional view of the hopper and its vicinity of the injection molding machine included in the injection molding system of FIG. 1 (with the shutter open). FIG. 2 is an enlarged sectional view of the hopper and its vicinity of the injection molding machine included in the injection molding system of FIG. 1 (with the shutter closed). FIG. 2 is an enlarged sectional view of the hopper and its vicinity of the injection molding machine included in the injection molding system of FIG. 1 (with the shutter reopened).

An injection molding system according to an embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

FIG. 1 is a diagram showing a schematic configuration of an injection molding system according to an embodiment of the present invention. FIG. 2 is a functional block diagram of the injection molding system of FIG. 1. 3 to 5 are enlarged sectional views of the hopper and its vicinity of the injection molding machine included in the injection molding system of FIG. 1, and show the shutter in an open state, a closed state, and a re-opened state.

As shown in FIG. 1, the injection molding system 1 according to the present embodiment includes a resin supply device 5 and an injection molding machine 8.

In this injection molding system 1, a drying container 6 of a resin supply device 5 contains granular or powdered resin P whose temperature and humidity are controlled. By suctioning with the suction device 7 of the resin supply device 5, the resin P is supplied from the drying container 6 to the injection molding machine 8 through the transfer pipe 5a. Then, the resin P plasticized by the injection molding machine 8 is injected and filled into the cavity 83 formed by the stationary mold 81 and the movable mold 82 .

The injection molding machine 8 includes a mold clamping device 10, an injection device 20, and a control device 30.

The mold clamping device 10 includes a fixed die plate 11, a movable die plate 12, and a mold clamping drive mechanism 13. A stationary mold 81 is attached to the stationary die plate 11 . A movable mold 82 is attached to the movable die plate 12 . The mold clamping drive mechanism 13 clamps the fixed mold 81 and the movable mold 82 in the left-right direction in FIG. 1 by the fixed die plate 11 and the movable die plate 12 to generate mold clamping force.

The injection device 20 includes a heating cylinder 21, a screw 22, and a screw drive mechanism 23. The heating cylinder 21 is arranged on the right side of the fixed die plate 11 in FIG. A nozzle 21 a that touches the stationary mold 81 is provided at the front end of the heating cylinder 21 . The screw 22 is housed in the heating cylinder 21 so as to be rotatable and movable back and forth. The screw drive mechanism 23 plasticizes the resin P and injects it into the cavity 83 by rotating and moving the screw 22 back and forth within the heating cylinder 21 .

The injection device 20 also includes a hopper 25, a shutter 26, a shutter drive mechanism 27, and a remaining amount sensor 28.

The hopper 25 stores resin P to be supplied to the heating cylinder 21. As shown in FIG. 3, the hopper 25 includes a tube portion 25a, an accumulation portion 25b, and a lid body 25c. The tube portion 25a is formed into a circular tube shape using transparent glass or synthetic resin so that the inside can be visually recognized. The tube portion 25a may have a shape other than a circular tube, such as a square tube or a hexagonal tube, for example. The tube portion 25a is arranged along the vertical direction, and its lower end is connected to the resin supply port 21b of the heating cylinder 21. The storage section 25b has a cylindrical shape with a larger diameter than the tube section 25a, and is connected to the upper end of the tube section 25a. The lower part of the storage portion 25b is formed into an inverted conical shape. The upper opening of the storage section 25b is closed with a lid 25c. A transfer pipe 5a and an exhaust pipe 5b of the resin supply device 5 are arranged to penetrate through the lid body 25c.

The shutter 26 is arranged near the upper end of the tube portion 25a of the hopper 25. That is, the shutter 26 is arranged to partition the inside of the hopper 25 into a space inside the pipe portion 25a (first supply section S1) and a space inside the accumulation section 25b (second supply section S2). The first supply section S1 is connected to the heating cylinder 21. The second supply section S2 is connected to the transfer pipe 5a. The shutter drive mechanism 27 moves the shutter 26 in the horizontal direction to connect or separate the first supply section S1 and the second supply section S2.

The remaining amount sensor 28 is composed of, for example, a photoelectric sensor. The remaining amount sensor 28 is installed on the outer peripheral surface of the tube portion 25a of the hopper 25, and outputs a signal corresponding to the remaining amount (height) of the resin P in the tube portion 25a.

The control device 30 controls the operation of the injection molding system 1 as a whole. The control device 30 includes a microcomputer. The control device 30 controls the operation of each drive mechanism such as the mold clamping drive mechanism 13, the screw drive mechanism 23, the shutter drive mechanism 27, and the suction device 7 of the resin supply device 5. Further, the control device 30 detects the remaining amount of resin P in the pipe portion 25a based on the signal output from the remaining amount sensor 28.

Next, an example of the operation of the injection molding system 1 of the present embodiment described above will be described with reference to FIGS. 3 to 5.

As shown in FIG. 3, the hopper 25 of the injection molding machine 8 of the injection molding system 1 stores resin P in an amount that can be injected multiple times. The control device 30 of the injection molding machine 8 controls each drive mechanism to perform a mold clamping operation for clamping a stationary mold 81 and a movable mold 82, and an injection for injecting and filling a cavity 83 with plasticized resin P. The plasticizing operation of plasticizing and measuring the resin P to be injected into the cavity 83 and the mold opening operation of opening the stationary mold 81 and the movable mold 82 to take out the molded product are repeated. In this embodiment, during the mold opening operation, the screw 22 does not rotate or move forward or backward, but is stopped. In addition to this, for example, a state may be provided in which the screw 22 stops between each operation.

The control device 30 controls the inside of the pipe portion 25a of the hopper 25 (first supply The remaining amount of resin P in section S1) is detected. Then, the control device 30 determines that the height of the resin P in the pipe section 25a is lower than the height at which the remaining amount sensor 28 is installed, that is, the remaining amount of the resin P in the first supply section S1 is less than the reference remaining amount R. When this is detected, a resin supply signal is output to the suction device 7. The resin supply signal is a signal requesting the supply of resin P. Thereby, a predetermined amount of resin P that can be injected multiple times is supplied from the drying container 6 to the storage section 25b (second supply section S2) of the hopper 25 through the transfer pipe 5a by the suction device 7.

When the remaining amount of resin P in the first supply section S1 is less than the reference remaining amount R and the screw 22 is rotating or moving forward and backward and has not stopped, the control device 30 operates the shutter drive mechanism as shown in FIG. 27 to close the shutter 26. This prevents the first supply section S1 and the second supply section S2 from being separated and supplying the resin P from the second supply section S2 to the first supply section S1.

When the remaining amount of resin P in the first supply section S1 is less than the reference remaining amount R and the screw 22 is not rotating or moving forward or backward but is stopped, the control device 30 controls the shutter drive as shown in FIG. The mechanism 27 is controlled to open the shutter 26. Thereby, the first supply section S1 and the second supply section S2 are connected, and the resin P is supplied from the second supply section S2 to the first supply section S1.

The control device 30 does not output a resin supply signal to the suction device 7 when the remaining amount of resin P in the first supply section S1 is equal to or greater than the reference remaining amount R. Therefore, the resin P in the hopper 25 does not fly up because the resin P is not supplied into the storage section 25b. Good too.

By doing so, in the injection molding machine 8, when the screw 22 is stopped, the resin P is supplied to the first supply section S1, and when the screw 22 is not stopped, the resin P is supplied to the first supply section S1. , prevents resin from being supplied to the first supply section S1.

As described above, according to the injection molding system 1 of the present embodiment, only when the screw 22 housed in the heating cylinder 21 is stopped, the space inside the pipe portion 25a connected to the heating cylinder 21 in the hopper 25 ( Resin P is supplied to the first supply section S1). With this arrangement, although there is a risk that the resin P will fly up in the hopper 25 as the resin P is supplied, the resin P will not be supplied to the heating cylinder 21 because the screw 22 is stopped. After the flying resin P falls, the screw 22 is operated to supply the resin P to the heating cylinder 21. Therefore, when the resin P is supplied to the heating cylinder 21, the load applied to the resin P can be prevented from changing suddenly, and variations in the state of the resin P can be suppressed.

The injection molding machine 8 also includes a space inside the tube part 25a (first supply part S1) inside the hopper 25, and an accumulation part 25b connected to the resin supply device 5 located above the first supply part S1. When the remaining amount of resin P in the first feeding section S1 is less than the reference remaining amount R, the suction machine of the resin feeding device 5 7 and a control device 30 that outputs a resin supply signal. Then, when the remaining amount of resin P in the first supply section S1 is less than the reference remaining amount R and the screw 22 is not stopped, the control device 30 closes the shutter 26 and controls the remaining amount of resin P in the first supply section S1. The shutter 26 is configured to open when the amount is less than the reference remaining amount R and the screw 22 is stopped. By doing this, the resin P is supplied from the second supply section S2 of the hopper 25 to the first supply section S1 only when the screw 22 is stopped, so when the resin P is supplied to the heating cylinder 21, It is possible to prevent the load applied to the resin P from suddenly changing, and to suppress variations in the state of the resin P.

In the embodiment described above, the interior of the hopper 25 is partitioned into the first supply section S1 and the second supply section S2 by the shutter 26, but the present invention is not limited to such a structure. For example, in the injection molding system of the embodiment described above, the shutter 26 may be omitted. In such a configuration in which the shutter 26 is omitted, the entire inside of the hopper 25 can be regarded as a first supply section S1 that is connected to the heating cylinder 21 and also connected to the resin supply device 5. Then, the control device 30 controls the suction machine 7 of the resin supply device 5 according to the timing when the remaining amount of resin P in the hopper 25 (first supply section S1) is less than the reference remaining amount R and the screw 22 stops. Outputs resin supply signal. That is, when the control device 30 detects that the remaining amount of resin P in the hopper 25 has become less than the reference remaining amount R, it outputs a resin supply signal at the appropriate timing. This timing coincides with the timing at which the screw 22 stops if there is no time difference between when the resin supply signal is output and when the resin P is actually supplied into the hopper 25 (including when there is almost no time difference). do. Alternatively, if there is a time difference between when the resin supply signal is output and when the resin P is actually supplied into the hopper 25, this timing may be set to an earlier timing than when the screw 22 stops, taking into account the time difference. do. By adopting such a configuration, the resin P can be supplied from the resin supply device 5 into the hopper 25 at the same time as the screw 22 is stopped. When the resin P is supplied into the hopper 25 and the resin P is supplied to the heating cylinder 21, sudden changes in the load applied to the resin P can be prevented, and variations in the state of the resin P can be suppressed.

Although the embodiments of the present invention have been described above, the present invention is not limited to these examples. Additions, deletions, and design changes to the above-described embodiments by those skilled in the art as appropriate, as well as combinations of features of the embodiments, may also be considered as the present invention, as long as they have the gist of the present invention. within the scope of the invention.

1... Injection molding system, 5... Resin supply device, 5a... Transfer pipe, 5b... Exhaust pipe, 6... Drying container, 7... Suction machine, 8... Injection molding machine, 10... Mold clamping device, 11... Fixed die plate, 12... Movable die plate, 13... Mold clamping drive mechanism, 20... Injection device, 21... Heating cylinder, 21a... Nozzle, 21b... Resin supply port, 22... Screw, 23... Screw drive mechanism, 25... Hopper, 25a... Pipe Part, 25b...accumulation part, 25c...lid body, 26...shutter, 27...shutter drive mechanism, 28...remaining amount sensor, 30...control device, 81...fixed side mold, 82...movable side mold, 83...cavity , S1...first supply section, S2...second supply section, P...resin, R...reference remaining amount

Claims (2)

An injection molding machine comprising a heating cylinder, a hopper for storing resin to be supplied to the heating cylinder, and a screw housed in the heating cylinder,
A shutter arranged to partition the inside of the hopper into a first supply section connected to the heating cylinder and a second supply section located above the first supply section and connected to a resin supply device. and,
a control device;
The control device,
when the remaining amount of resin in the first supply section is less than a reference remaining amount and the screw is not stopped, closing the shutter;
An injection molding machine characterized in that the shutter is configured to open when the remaining amount of resin in the first supply section is less than the reference remaining amount and the screw is stopped. An injection molding machine according to claim 1 ;
An injection molding system comprising: a resin supply device that supplies resin to a hopper of the injection molding machine in accordance with a resin supply signal output from the injection molding machine.

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