JPS649176B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a feeder device for an in-line screw injection molding machine.

Generally, the above-mentioned inline screw type injection molding machine differs from an extruder in that the screw of the injection molding machine (hereinafter referred to as the main screw) rotates only during the plasticizing process (during the measuring process) and stops during other processes. During the injection process, the main screw stops its rotation and moves forward. Therefore, when the main screw moves forward while its rotation is stopped, no raw material is supplied. Therefore,
Only this part of the screw groove becomes hollow, and even if the feeder screw rotates to feed material during the next process, the filling density of the raw material in the hollow part is not sufficient, and the inside of the screw groove remains rough. There is a problem that plasticization by the main screw cannot be done uniformly because the parts and dense parts are arranged alternately.

Therefore, in order to solve the above problem, it has been proposed to rotate the feeder screw even during the injection process.

That is, as shown in FIG. 1A, during the measuring process, the main screw 1 rotates while plasticizing the material.
While the material is transferred to the front of the screw 1 and accumulated as shown in a, the main screw 1 itself is retreated by a distance l from the position shown by the chain line 2 to the retraction limit shown in the figure, during which time the feeder (not shown) is continuously moved. Material is supplied from a material supply port 3 communicating with.

On the other hand, during the injection process, as shown in FIG. The main screw 1 moves forward without rotating to the limit position, and the material is supplied from the material supply port 3 of the main screw 1 at the backward limit into the screw groove in the rear portion 4 which is not clogged with material as shown in b. Therefore, the amount of material supplied to the injection molding machine differs between the metering process and the injection process. Therefore, in order to vary the amount of material supplied to the injection molding machine in this way, a circuit as shown in FIG. A setting signal set in a speed setting device 17 is applied to the motor 16 that drives the feeder screw 15 via the contact 14 of the relay 13. The signal 12 during the injection process is applied to the relay 13 via a switch 19 that is opened and closed by a timer 18. When the signal 12 is generated, the switch 19 is closed by the timer 18, and the signal 12 is applied to the relay 13. 13, and a timer 18 causes a switch 19 to open when a predetermined period of time has elapsed. Therefore, the signal 12 during the injection process is transmitted to the relay 13.
When the feeder screw 15 is operated, the feeder screw 15 rotates at the speed set in the speed setting device 17 for the time set in the timer 18, and material is supplied to the main screw during the injection process. However, the speed setting value for the feeder screw 15 is the same value set in the speed setting device 17 that is common to the measurement and injection processes, and the only difference in the amount of material fed to the injection molding machine is due to the difference in time. It is.

By the way, the material that must be supplied to the main screw differs during the plasticizing process and during the injection process, as shown in FIG. 1A and 1B.

In other words, as shown in Figure 1A, the amount of material a when the main screw is retreated by l from the chain line position during the measuring process.
As shown in FIG. 1B, the amount b of the material supplied when the main screw moves forward by l during the injection process is different, and the plasticization of the material is not uniform.

Therefore, with timer control, during the injection process, that is, within the short time that the main screw moves from the retraction limit to the forward limit, the missing amount of material necessary for metering the next cycle is accurately supplied into the cavity of the main screw. The amount of material fed from the feeder to the molding machine is not constant, and the plasticization of the material is not uniform.

The present invention eliminates the above-mentioned drawbacks, and allows the feeder screw to feed material at a rate commensurate with the rotational speed of the main screw during the metering process and the injection process. To provide a feeder that can be filled with materials.

Next, one embodiment of the present invention will be described with reference to FIG. 3. Reference numeral 21 denotes a screw rotation speed detector, which detects the rotation speed of the main screw 22 which is rotationally driven by the motor 20. 23 is a motor that rotates the feeder screw 24, and a controller 2
5. 26 is a signal emitted from a signal transmitter (not shown) during the injection process, and when the signal 26 activates a relay 27, its A contact 2 is activated.
8 is connected and the feeder screw 2 is in the injection process.
The setting signal of the first feeder screw speed setting device 29 for setting the rotation speed of the controller 2
5.

Reference numeral 30 denotes a signal during the weighing process that is emitted from a signal transmitter (not shown). When the signal 30 activates a relay 31, its A contact 32 is connected, and the feeder screw 24 is activated in accordance with the rotational speed of the main screw 22. A setting signal from a second feeder screw speed setting device 33 for setting the rotation speed is applied to the controller 25. The second feeder screw speed setting device 33 receives a signal from the screw rotation speed detector 21 that detects the rotation speed of the main screw 22 during the metering process,
The main screw 22 and the feeder screw 2 are preset in the second feeder screw speed setting device 33.
4, so as to supply an amount of material commensurate with material transfer and plasticization corresponding to the rotational speed of the main screw 22, according to a setting value based on the ratio of the rotational speed to the rotational speed of the main screw 22.
The rotation speed of the feeder screw 24 is calculated and determined, and the feeder screw 24 is rotated.

Since the present invention has the configuration described above, the feeder is rotated at the optimal rotation speed for each process by different rotation speed setting values during the metering process and the injection process, and the feeder is rotated at the optimum rotation speed for each process. The amount of material supplied is commensurate with the material transfer and plasticization of the main screw, making it possible to ensure material supply especially during the injection process, and to prevent the formation of coarse and dense parts in the screw groove. Without,
Plasticization can be uniformly performed.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the operation of the screw of an injection molding machine, A is a diagram showing the measuring process, B is a diagram showing the injection process, Fig. 2 is a conventional feeder circuit diagram, and Fig. 3 is a feeder circuit diagram according to the present invention. . 22...Main screw, 24...Feeder screw, 26...Signal during injection, 29...First feeder screw speed setting device, 30...Signal during metering, 33...Second feeder screw speed setting device.

Claims (1)

[Claims] 1 In a feeder device that supplies material to an in-line screw type injection molding machine having a main screw rotating within a cylinder, there is provided a screw rotation speed detector 21 for detecting the rotation speed of the main screw, and a rotation of the feeder screw during the injection process. a first feeder screw speed setting device 29 with a speed set;
a second feeder screw speed setting device 33 for setting the rotation speed ratio of the main screw and feeder screw, and outputting a feeder screw rotation speed command signal in accordance with the rotation speed of the main screw detected by the screw rotation speed detector 21; During the injection process, the output signal from the first feeder screw speed setting device is applied to the controller 25, and during the metering process, the output signal from the second feeder screw speed setting device is applied to the controller 25 for feeder screw control. A feeder device for an injection molding machine, characterized in that it has switches 28 and 32.