JPH08300427A - Resin supply device and resin supply method - Google Patents

Abstract

(57) [Summary] [Purpose] The object is to obtain a molded article having stable and excellent quality by maintaining the molten state of the homogenized resin. A device for supplying resin to an injection device of an injection molding machine or a blow molding machine, comprising a plurality of resin supply ports 30 arranged at intervals of approximately one screw pitch in the screw axis direction, and the resin supply port An on-off valve 60 that shuts off 30
And a hopper 40 connected to this.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin supplying device and a resin supplying method in a screw in-line type injection device used in an injection molding machine or a blow molding machine, and more particularly,
It is intended to maintain the molten state of the resin during plasticizing and to improve the quality of the molded product.

[0002]

2. Description of the Related Art A screw-in-line type injection device in an injection molding machine or a blow molding machine has a nozzle 3 at its tip and a temperature control device (heater 1) at its outer periphery, as shown in FIG.
It comprises a barrel 1 with 1). This barrel 1
It is arranged so that the nozzle 3 can face the material injection port of the die 4. The resin fed from the hopper 10 into the barrel 1 is transferred from the material supply section to the compression section by the screw 2 which is rotationally driven by the hydraulic motor 5, and the groove depth of the screw groove is gradually reduced in the compression section. Receives compression. In this process, the resin between the flights 20 of the screw 2 transfers heat from the inner wall surface of the barrel 1 by the heater 11 and the resin itself due to the rotating action of the screw 2, and between the resin and the barrel 1 or the screw 2. The generated frictional heat (generated by shearing energy) forms a molten melt film on the inner wall surface of the barrel 1,
Furthermore, it is collected by the flight 20, and the flight 20
A melt pool is formed on the surface. Thus, the resin in the barrel 1 in the process of promoting plasticization is composed of three parts, a melt film, a melt pool, and a solid bed which has not yet reached the melting point, and as the screw 2 rotates, While being transferred further forward, the unmelted portion (solid bed) is continuously melted by the heating from the heater 11 and the rotating action of the screw 2.
In order to obtain a homogeneous molten plasticized resin by removing the unmelted portion in the measuring section of the screw 2.

[0003]

In the conventional injection apparatus as described above, since there is only one resin supply port, the screw is retracted in the plasticizing and measuring step of the resin, so that the screw located in front of the supply port. Since the length gradually becomes shorter, the effective screw length decreases. As a result, the preheating time of the supplied resin and the amount of heat generated by shearing between the screw and the inner peripheral surface of the barrel are reduced, and the resin temperature and resin physical property values change between the beginning of plasticization measurement and the end of plasticization measurement. As a result, it becomes difficult to uniformly supply the molten resin, and as a result, the molten state of the resin injected into the mold or die becomes non-uniform, and the physical properties of the molded product cannot be kept uniform throughout the product. However, there is a problem that a product of good quality cannot be obtained.

[0004]

In order to solve such problems and enable plasticizing and metering of a resin having a uniform molten state, the apparatus of the present invention (first invention) uses an injection molding machine or A resin supply device for a screw in-line type injection device of a blow molding machine, the supply device comprising a plurality of resin supply ports arranged at a distance of approximately a screw pitch in the screw axial direction, each of the resin supply ports being provided. An opening / closing valve capable of shutting off the communication between the resin supply ports is arranged at each of the ports, and a hopper for supplying the resin to each of the resin supply ports is connected. In the device of the present invention (second invention), the opening / closing means of the opening / closing valve is a hydraulic cylinder or a pneumatic cylinder, and the method of the present invention (third invention).
A method of supplying a resin in a screw-in-line type injection device of an injection molding machine or a blow molding machine having a plurality of resin supply ports of the supply device according to the first aspect of the present invention, wherein a plurality of resin supply ports are provided at the start of plasticization measurement. Open the on-off valve only at the resin supply port on the front row to supply the resin,
The amount of screw retreat is measured during plasticization metering, and each time the amount of screw retreat reaches the screw pitch, the on / off valve of the resin supply port, which has been communicating until then and is supplying resin, is closed, and the resin supply port is followed. It was decided to supply the resin by opening the on-off valve of the resin supply port.

[0005]

In the resin feeding apparatus and feeding method of the present invention, at the initial stage of plasticization measurement, all the resin feeding ports arranged in the axial direction of the screw are closed except the foremost resin feeding port. The resin is supplied only from the resin supply port, and plasticization is measured. Then, the amount of screw retreat is detected during plasticization measurement, and when the amount of screw retreat reaches one screw pitch, the foremost resin supply port is closed to stop the supply and the subsequent resin supply port is opened. Supply the resin. As described above, every time the screw retreat amount reaches one pitch of the screw, the supply from the resin supply port, which has been supplying resin until then, is stopped, and the resin supply is switched to the resin supply port from the next succeeding resin supply port. To go. By doing in this way, the length of the screw in front of the resin supply port that actually supplies the resin is maintained at approximately the same length, and the amount of heat applied to the resin is made constant, so that the molten state of the resin is It is kept almost constant and the resin temperature is made uniform.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 5 relate to the present invention, FIG. 1 is a vertical cross-sectional view of a resin supply device (in the initial state of plasticization measurement), and FIG. 2 is a vertical cross-sectional view of a resin supply device (at the end of plasticization measurement). FIG. 3 is a cross-sectional view taken along line AA of FIG. 1,
4 to 5 are graphs showing the correlation between the screw position and the resin temperature, FIG. 4 shows the case where there are two resin supply ports, and FIG. 5 shows the case where there are three resin supply ports.

1 to 3 show a resin supply device 100 in the case of two resin supply ports 30, wherein a plurality of resin supply ports 30 are arranged in the barrel 1 in the axial direction of the screw 2 at approximately one screw pitch. A hopper housing 50 is erected at each of the resin supply ports 30 via the injection housing 1A, and the hopper housing 50 is vertically moved by the operation of the hydraulic cylinder 62 inside the resin supply ports 30 so that the resin supply ports 30 can be opened. Open / close valve 60 to open / close
Is arranged. In addition, adjacent hopper housings 50,
A hopper 40 and a chute 42 as shown in FIG.
A shutter 70 that is fixed to the piston rod 62a and moves up and down in conjunction therewith is provided, and the resin path of the hopper 40 and the chute 42 is shut off at the same time when the opening / closing valve 60 is closed. In the case of FIGS. 1 to 3, an example in which the number of the resin supply ports 30 is two is shown. However, since the total screw retreat amount during measurement is about 6 times the screw pitch, the resin supply ports 30, When the distance between the 30 members is one screw pitch, it is most preferable that the number of resin supply ports 30 is 6, but it is preferable that at least 3 to 4 be provided. As in the embodiment of FIG. 1, the resin supply port 3
The spacing between 0 and 30 was set to be slightly larger than one screw pitch, and was 1.5 to 2.0 times the screw pitch.

The operation of the resin supply apparatus 100 of the present invention thus constructed will be described. 1 and 2 show a case where two resin supply ports 30 are provided, and when starting the plasticizing measurement, as shown in FIG.
The on-off valve 60 of 0 is closed, and only the front resin supply port 30 is opened to supply the resin. During the measurement, the resin supplied from the resin supply port 30 is melted by the frictional heat generated by the rotation of the screw 2 and the heat transfer of the heater 11 around the barrel 1, and is accumulated in the resin reservoir in the front.
The screw 2 retracts. Then, when the screw retreat amount measured during measurement reaches a preset value, the shutter 70 and the opening / closing valve 60 are closed by lowering the piston rod 62a of the hydraulic cylinder 62 from the front resin supply port 30 to close the rear resin supply port 30. The supply port 30 is opened and the resin supply position is moved backward by the screw retreat amount. In this case, the set value for switching the supply position is about the distance between the two resin supply ports 30 and 30, and in the case of FIGS. 1 and 2 having two supply ports, about 1.5 to 2.0 times the screw pitch. Since the two resin supply ports are separated, it is preferable to switch the resin supply from the front to the rear when the screw retreat amount reaches this value.
FIG. 2 shows the state at the end of measurement. Further, in the resin supply device 100 in which the resin supply ports 30 are arranged in the axial direction of a plurality of screws of three or more, the distance between the resin supply ports 30 and 30 adjacent to each other is shortened as the number of the resin supply devices 100 increases, and the resin supply ports 30 are almost one screw. The pitch is set to about the pitch, and the switching is sequentially switched to the supply of the resin supply port 30 on the rear side every time the screw retreat amount reaches one screw pitch.

The temperature of the resin supplied to the injection device is measured by the thermometer 80 in the resin supply device 100 having such a plurality of resin supply ports 30, and the distribution of the resin temperature is examined. 4, it can be seen that the change in the resin temperature reaching the peak temperature depending on the screw position is leveled as compared with the conventional one supplied by one resin supply port 30 in FIG. Further, in the graph shown in FIG. 5 in the case where the number of the resin supply ports 30 is three, it was verified that the temperature change due to the screw position is further reduced and the uniform resin melting is achieved. The resin temperatures in the graphs of FIGS. 4 to 6 represent the resin temperatures measured by the thermometer 80 when the screw head 2a is at the positions P1, P2, P3, and P4, respectively.

Inferring from such data, it is desired that the number of resin supply ports 30 is as large as possible in order to make the resin melt uniform, and considering that the effective screw pitch is usually about 6 pitches, the resin supply is It is desirable to arrange about 3 to 5 mouths 30.

[0011]

As described above, according to the present invention,
The molten state of the resin is almost uniform during the plasticization measurement, and a homogeneous and stable molded product quality is secured. In addition, in the case of injection molding, since the molten state of the resin is homogenized, it is easy to set the molding conditions and the operability is improved.In blow molding, the above-mentioned homogeneous molten resin passes through the storage tank of the die. Therefore, a uniform parison can be discharged, and the quality is improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a resin supply device (initial stage of plasticization measurement) showing an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view of a resin supply device (end of plasticization measurement) showing an embodiment of the present invention.

FIG. 3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is a graph showing a correlation between a screw position and a resin temperature showing an example of the present invention.

FIG. 5 is a graph showing a correlation between a screw position and a resin temperature showing an example of the present invention.

FIG. 6 is a graph showing a correlation between a screw position and a resin temperature in a conventional example.

FIG. 7 is an overall vertical sectional view of a conventional injection molding machine.

FIG. 8 is an overall vertical sectional view of a conventional injection molding machine.

[Explanation of symbols]

 1 barrel 1A injection housing 2 screw 2a screw head 3 nozzle 4 mold 5 hydraulic motor 10 hopper 11 heater 20 flight 30 resin supply port 40 hopper 42 chute 50 hopper housing 60 on-off valve 62 hydraulic cylinder (or pneumatic cylinder) 62a piston rod 70 Shutter 80 Thermometer 100 Resin supply device

Claims (3)

[Claims] 1. A resin supply device for a screw in-line type injection device of an injection molding machine or a blow molding machine, wherein the supply device is a plurality of resin supply devices arranged at a distance of approximately screw pitch in the screw axial direction. An apparatus for supplying resin, which is provided with an opening, an opening / closing valve for arranging each of the resin supply openings to cut off the resin supply opening, and a hopper for supplying the resin to each of the resin supply openings is connected. . 2. The resin supply device according to claim 1, wherein the opening / closing means of the opening / closing valve is a hydraulic cylinder or a pneumatic cylinder. 3. A method of supplying resin in a screw in-line type injection apparatus of an injection molding machine or a blow molding machine comprising a plurality of resin supply ports according to claim 1, wherein the plurality of resin supply ports are provided at the start of plasticizing and weighing. The resin is supplied by opening the open / close valve only at the resin supply port in the front row of the above, and the screw retreat amount is measured during plasticizing and the resin is communicated in sequence until the screw retreat amount reaches the screw pitch. A resin supply method characterized in that the on-off valve of the resin supply port that has been supplied is closed, and the on-off valve of the resin supply port subsequent to the resin supply port is opened to supply the resin.