JPH03248825A - Material feed device of injection molding machine - Google Patents

Abstract

PURPOSE:To constitute simply and inexpensively the title device and make maintenance of the device easy further, by a method wherein a main body of a material feed device obtained by connecting a synthetic resin material feed part with a heating cylinder is divided into a plurality of stages, the stages each are communicated with each other through a falling hole of the synthetic resin material and at least the one stage is connected with a feed source of inert gas. CONSTITUTION:A main body 2 of a material feed device 1 is constituted by connecting its feed part 3 with a heating cylinder 5 of an injection molding machine provided with a screw shaft 4 and the upper part of the feed part 3 is divide into three stages with partition plates 6a, 6b. An innert gas cylinder 15 is connected with inner gas inflow holes 13, 14. Plastic raw materials 10 are dropped within the second stage part 8 from within the first stage part 7 through a drop hole 11 of the partition plate 6a, dropped within the third stage part 9 from within the second stage part 8 through a drop hole 12 of the partition plate 6b and fed further within a heating cylinder 5 through the feed part 3. Oxygen contained within the plastic raw materials is raised to the upper part by the innert gas which flows into the drop holes 11, 12 from the second stage part 8 and third stage part 9 in a dropping process of the drop holes 11, 12 and discharged outside through an upper opening part of the main body 2.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a material supply device for an injection molding machine, and particularly to an injection molding device for injection molding thermoplastic plastics.
Related to a device that removes oxygen in a material supply device or heating cylinder and replaces it with inert gas before the plastic material to be molded is plasticized [Prior art] Conventionally, a desired molded product is manufactured using an injection molding device. In injection molding, the problem of air or gases such as volatile gas being mixed into the molten raw material can be eliminated by removing the raw material from the supply section before reaching the molten state (i.e., solid state).
In 1977, a technology was developed to achieve this by removing gases such as oxygen from a material supply device or heating cylinder.
-22866, Japanese Patent Publication No. 46-28661, or Japanese Utility Model Application Publication No. 1-141016.

Therefore, the invention described in Japanese Patent Publication No. 46-22866 provides an airtight chamber between the cylinder base and the screw drive device in a synthetic resin molding machine equipped with a hopper that requires maintenance of vacuum or internal pressure. A discharge hole that can be opened and closed is provided at the bottom of the airtight chamber, a gasket is provided in the gap between the airtight chamber and the drive device to make it airtight, and the center of the screw drive tube axis of the drive device is provided. This is an airtight device for a synthetic resin molding machine, characterized in that an airtight seal with a spring or the like is provided between the base of the screw shaft and the drive shaft, which are exposed at the rear through the screw shaft.

In addition, the invention described in Japanese Patent Publication No. 46-28661 is provided with a screw shaft that is capable of rotating and reciprocating within the heating cylinder, and has a popper and a material drop that are involved in supplying the molding raw material to the screw shaft. In an injection molding machine having a vacuum-tight structure between the mouth and the heating cylinder where the molding material exists at least in solid form, the injection molding machine is vacuum-tightly connected to the rear end of the heating cylinder and communicated with a vacuum source. A flange with an opening, a vacuum-tight bellows whose front part is connected to the flange and is expandable and retractable, and a rear end of the bellows is restrained from moving in the axial direction with respect to a rear end of the screw shaft. The invention is characterized in that it is provided with a disc rotatably and vacuum-tightly held, and a guide means that holds the disc in a fixed part of the injection molding machine so as to be movable forward and backward in the axial direction of the screw shaft. This is an injection molding machine.

Furthermore, the invention described in Japanese Utility Model Application Publication No. 1141016 provides a material supply device for supplying a synthetic resin material used for injection molding to a material supply port provided at a base end of a heating cylinder of an injection molding machine. An air supply hole is provided in the wall surface leading to the opening, and the air supply hole and the outlet of the delivery means for sending out the inert gas are connected through an air supply pipe, so that the inert gas can be blown into the heating cylinder. This is a material supply device.

[Problem to be solved by the invention]

However, in the air-tight device of the conventional synthetic resin molding machine or injection molding machine, the air-tight maintenance mechanism in the hopper and heating cylinder is complicated, and when the current molding machine is modified and applied, Furthermore, even when manufacturing a new molding machine, it requires a great deal of cost and effort, and it also has drawbacks such as requiring a great deal of effort to maintain the structure to maintain airtightness.

In addition, the material supply device requires a large motor and a screw for material supply due to its configuration, and like the above devices, the manufacturing cost increases, and it is difficult to modify the molding machine of -G. It has the disadvantage of being costly.

Therefore, the present invention was developed to eliminate the drawbacks of these conventional devices.In a screw reciprocating injection molding machine, the plastic material is in a solid state (before melting) by removing ambient oxygen, etc. It is an object of the present invention to provide an apparatus that can remove gas, can be constructed simply and inexpensively, and is easy to maintain.

[Means and effects for solving the problems] A material supply device for an injection molding machine according to the present invention is a material supply device for an injection molding machine that supplies a synthetic resin material to a heating cylinder of an injection molding machine. The main body of the material supply device, in which the supply part is connected to the heating cylinder, is divided into a plurality of stages, and each stage is communicated through the drop hole for the synthetic resin material, and at least one of the stages is connected to the heating cylinder. The device is characterized in that it is constructed by connecting the section to an inert gas supply source.

FIG. 1 shows a conceptual diagram of the material supply device of the injection molding machine of the present invention, where l indicates the material supply device, and the main body 2 of the material supply device 1 has a supply section 3 connected to the screw shaft. 4 is connected to a heating cylinder 5 of an injection molding machine (not shown), and the upper part of the supply section 3 is connected to partition plates 6a and 6b.
The structure is divided into three stages.

Further, the respective step portions 7, 8 and 9 of the main body 2 are communicated with each other through drop holes 11 and 12 for the plastic raw material 10 opened in the respective partition plates 6a and 6b, and the second step portion 8 and the third step portion An inert gas inflow hole 1 is provided in the side wall of the portion 9.
3 and 14 are opened, and each inlet hole 13 and 14 is connected to an inert gas cylinder 15 via a conduit 16 and a pressure reducing valve 17, which is an inert gas supply source.

Further, a lid 18 is detachably attached to the upper opening of the main body 2.

Therefore, in the material supply device W1, the lid 1 of the main body 2
8 and insert the plastic raw material 1 into the first step 7 of the main body 2.
At the same time, inert gas is introduced from the inert gas pump 15 into the second and third stage portions 8 and 9 through the inlet holes 13 and 14 via the pressure reducing valve 17 and the conduit 6.

In this state, the plastic raw material 10 falls from inside the first stage part 7 into the second stage part 8 through the drop hole 11 of the partition plate 6a, and from inside this second stage part 8 falls through the drop hole 12 of the partition plate 6b. It falls into the third stage section 9 through the supply section 3 and is further supplied into the heating cylinder 5 through the supply section 3 .

In addition, in connection with the supply of the plastic raw material 10 into the heating cylinder 5, the inert gas flowing into the inert gas cylinder 15 through the inlet holes 13 and 14 is supplied to the second and third inert gas cylinders.
The steps 8 and 9 are filled and the first and second
Oxygen that flows into the steps 7 and 8 through the drop holes 11 and 12, and is contained in the first step 7 and the plastic raw material 10, exits through the upper opening of the main body 2 (the gap in the lid 18). be discharged.

Moreover, at the same time, the oxygen contained in the plastic raw material 10 is transferred to the second stage 8 during the falling process of the drop holes 11 and 12.
The inert gas flowing into the openings 11 and 12 from the third step 9 rises to the top and is discharged to the outside from the upper opening of the main body 2, replacing the inside of the main body 2 with the inert gas and the inside of the heating cylinder 5. It is also possible to efficiently perform the replacement of

〔Example〕

Embodiments of the material supply device for an injection molding machine of the present invention will be described below with reference to the drawings.

(First Embodiment) Figures 2 to 5 show the first embodiment of the present invention, in which Figure 2 is a schematic explanatory diagram of the device, Figure 3 is a perspective view of the first step of the main body, and Figure 4 The figure is a perspective view of the second stage portion of the main body, and FIG. 5 is a perspective view of the lid.

Now, in the configuration of the material supplying device 1 in this embodiment, the configuration that is different from the configuration of the device 1 shown in the first diagram is that the first
In addition to the configuration of the second step portions 7 and 8, the configuration of the lid body 18 will be described below.

First, the partition wall plate 6a of the first stage part 7 of the main body 2 is inclined so that it becomes lower from the outer circumference to the center part, and the center part has a bearing part 21 having a through hole 20 for the rotating shaft 19. The first step portion 7 is placed upright and the outer circumference of the bearing portion 21 is
Two partition plates 22 and 23 are erected between the outer peripheral walls of the partition plate 6 and are positioned near the center between the partition plates 22 and 23.
A ventilation hole 24 is opened in A, and the hole 1 for dropping the plastic raw material 10 is placed on the side of one of the partition plates 22.
1, the first stage part 7 is provided with an input part 25 for the plastic raw material 10 and a ventilation part 26 (see FIG. 3).

In addition, the second step part 8 has a connecting part 27 which is rotatably provided at the center of the partition wall plate 6b and which connects to the cylindrical rotating shaft 19. Six partition plates 28 are arranged radially at predetermined intervals between them, and each partition plate 28 divides the inside of the second step 8 into six chambers.

Each of the partition plates 28 is fixed to the connecting part 27,
The connecting portion 27 is rotated by the rotation of the rotating shaft 19, and is rotatably supported on the upper side of the partition wall plate 6b.

Further, the rotating shaft 19 is fixedly connected to a connecting part 27 and also has a bearing part 29 provided in the through hole 20 of the bearing part 21 of the first stage part 7 and in the center of the lid body 18 shown in FIG. A bevel gear 30 and a bevel gear 32 of the rotary drive shaft 31 extend to the upper side of the main body 2 and are fixed to the upper end of the rotary shaft 19.
It is connected to a stepping motor 33 via.

Further, the partition wall plate 6b has a structure that is sloped downward toward the center, similar to the partition wall plate 6a of the first stage portion 7, and is positioned near the center as shown in FIG. A drop hole 12 is opened.

Furthermore, the ventilation holes 24 and the drop holes 11 and 12 are arranged in such a way that they do not open simultaneously into the same chambers among the rooms constituted by the partition plates 28, as shown in FIG. It is arranged.

The other configurations are the same as the configuration shown in the first figure, and the same components are given the same numbers and their explanations will be omitted.

In the material supply device 1 having the above configuration, first, the lid 18 is opened and the plastic raw material 10 is introduced into the input portion 25 of the first stage portion 7 of the main body 2 .

The plastic material 10 introduced into the input section 25 falls into the second stage section 8 through the drop hole 11 of the partition wall plate 6a.

At this time, the drop holes 11 and 12 and the ventilation hole 24 are arranged to open into separate chambers among the chambers divided by the partition plates 28 in the second step 8, respectively.
For example, assuming the state shown in the second figure, the inert gas inflow hole 13 is located in the chamber where the ventilation hole 24 is open, the drop hole 11 is located in the adjacent chamber, and the drop hole 12 is located in the adjacent chamber. In this state, the plastic raw material 10 in the input section 25 passes through the drop hole 11 into a chamber separated by the partition plate 28 of the second stage section 8 and into which the inert gas inlet hole 13 opens and the drop hole 12 opens. Dropped into the empty chamber.

Therefore, the plastic raw material 10 is in the drop hole 11 in the room.
Waiting until the room is filled with water, the stepping motor 33 is activated to rotate the rotary shaft 19 and rotate the partition plate 28 together with the connecting portion 27 by a set angle. Filled plastic raw material 10
is moved to the opening position of the inert gas inflow hole 13.

Therefore, the oxygen mixed into the Plus Deck raw material 10 filled in one chamber divided by the partition plate 28 is
At the opening position of the inert gas inflow hole 13, the inside of the room is replaced by an inert gas such as chino gas or argon gas that flows into the same room from the inert gas pump 15 through the pressure reducing valve 17 and the conduit 16. By this, vent hole 2
4 into the ventilation section 26 of the first stage section 7, and is also discharged to the outside through the gap in the lid body 18.

Further, due to the movement of the partition plate 28 due to the intermittent rotation of the rotating shaft 19 by the stepping motor 33, the inert gas in the room adjacent to the opening position of the inert gas inflow hole 13 is filled with the inert gas in the room filled with the plastic raw material 10. During the gas replacement, the plastic raw material 10 is filled from the input part 25 of the first stage part 7 through the drop hole 11, and furthermore, at the time of filling, the stepping motor 33 ('l
Due to the rotational movement of the partition plate 28, the inert gas inflow reaches the opening of the hole 13, and the same inert gas replacement as described above is performed.
Eventually, when reaching the opening of the drop hole 12, the plastic raw material 10 in the same chamber falls into the third stage section 9 through the drop hole 12, and the plastic raw material 10 in the same chamber falls into the third stage section 9, which is not shown in FIG. It is supplied into the heating cylinder 5 through.

In addition, regarding the control of the stepping motor 33, the number of each partition plate 28 of the second stage section 8, the falling speed of the plastic raw material 10 into each chamber via the drop hole 11, and the inertness of each chamber at the opening of the inflow hole 13 are controlled. Control is performed using a predetermined set angle and time depending on the gas replacement rate, etc., and is carried out by setting the partition plate 28 to move by 30 degrees every 10 seconds, for example.

Thereafter, by continuously performing the above operations, the plastic raw material 10 can be supplied to the injection molding machine.

Particularly in the case of this embodiment, the second stage part 8 itself of the main body 2 can be further divided into each chamber, and the inert gas can be replaced with the inert gas, and more effective replacement can be performed with a simple configuration. .

(Second Embodiment) FIGS. 6 and 7 show a second embodiment of the present invention.
The figure is a schematic explanatory diagram of the apparatus, and FIG. 7 is a perspective view of a rotating disk provided in the second step.

The material supply device 1 of this embodiment has the partition plate 22 of the first embodiment.
．． 23 and 28, a rotating disk 34.
35 is rotatably equipped, the first and second stage parts 7 and 8 are connected through a conduit 36, and the first stage part 7 is provided with an outflow pipe 37.Other configurations are as follows. It has the same configuration as the first embodiment, and the same components are given the same numbers and their explanations will be omitted.

Further, the rotating disks 34 and 35 are respectively connected to the partition wall plate 6.
Both discs 34 and 35 are rotatably mounted on the lower side of a and the upper side of the partition wall plate 6b, and both discs 34 and 35 are fixed to the rotating shaft 19 and rotated intermittently by the intermittent drive of the stepping motor 33. As shown in FIG. 7, the drop holes 38 and 39 are formed in symmetrical positions corresponding to the drop holes 11 in the partition plates 6a and 6b, respectively.

Thus, the inert gas is introduced into the second and third stage portions 8 and 9 through the inlet holes 13 and 14 from the inert gas cylinder 15 through the pressure reducing valve 17 and the conduit 16. The inert gas that has flowed into the second stage section 8 flows into the first stage section 7 through the conduit 36, and removes the oxygen in the first stage section 7 through the outflow pipe 37. By discharging, the inert gas in the group 7 is replaced at the same time.

Therefore, under such conditions, the plastic raw material 10 introduced into the first step 7 of the main body 2 is placed in the drop hole 38 of the disk 34 of the second step 8 which rotates with the rotation of the rotating shaft 19. At the point when it matches the drop hole 11 of 6a, the second step part 8
fall inside.

At this point of fall, the plastic raw material 10
The remaining oxygen contained therein is discharged into the first stage part 7 by the inert gas flowing into the second stage part 8, and the oxygen in the conduit 36 is also discharged to the outside through the outflow pipe 37. This makes it possible to prevent oxygen from flowing into the second stage portion 8.

Further, after waiting for a predetermined amount of plastic raw material 10 to be dropped into the second stage section 8, the rotating shaft 19 rotates again and the disk 3 is rotated again.
4.35 is rotated 180 degrees to stop the plastic raw material 10 from falling from the first stage part 7 into the second stage part 8, and the drop hole 39 of the rotating disk 35 is aligned with the drop hole 12 of the partition plate 6b. , and the plastic raw material 10 in the second stage 8
falls into the third stage section 9 and is further supplied to the heating cylinder 5 of the injection molding machine via the supply section 3.

By continuously performing similar operations thereafter, the required raw material can be supplied into the heating cylinder 5 of the injection molding machine while removing oxygen from the plastic raw material 10.

In addition, in the case of this embodiment, in addition to obtaining the same effects as in the first embodiment, by connecting the first stage section 7 and the second stage section 8 through the conduit 36, 5- More effective inert gas replacement can be achieved.

Although the description has been made for the case where each step of the main body 2 shown in the first and second embodiments has three steps, the number of steps is not limited to this, and may be implemented with the required number of steps. Other configurations can also be implemented with necessary design changes, and are not limited to the configurations of the devices of the first and second embodiments.

〔Effect of the invention〕

According to the present invention, by adding a simple structure to the material feeding device of an injection molding machine or by improving the existing device, the material feeding device and the inside of the cylinder can be adjusted while the feedstock is a pellet-like solid. Since it is filled with inert gas, thermal deterioration (oxidation) of the material and foreign substances (additives) within the material can be prevented.

In addition, since the material has a thermal decomposition temperature compared to air, it is possible to raise the molding temperature and lower the viscosity of the material, making it possible to mold with a lower injection pressure.16 As a result, the mold clamping of the injection molding machine Capacity can be saved, and with the same mold clamping force, it is possible to mold a molded product with a larger projected area.

Moreover, since there is almost no oxidation compared to molding in air, the generation of thermal decomposition gas due to oxygen in the material can be extremely reduced, and a dense molded product without bubbles can be obtained.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram of the material supply device of the injection molding machine of the present invention;
2 to 5 show a first embodiment of the present invention, FIG. 2 is a schematic explanatory diagram of the device, FIG. 3 is a perspective view of the first step of the main body, and FIG. 4 is a perspective view of the second step of the main body. FIG. 5 is a perspective view of the lid, FIGS. 6 and 7 show the second embodiment of the present invention, FIG. 6 is a schematic explanatory diagram of the device, and FIG. It is a perspective view of the rotating disk provided in the step part. 1... Material supply device 2 - Main body 3... Supply section 4... Screw shaft 5... Heating cylinders 6a, 6b... Partition plate 7.8.9 -... 1st to 3rd stage Part 10... Plastic raw material 11.12... Fall hole 13.14... Inflow hole 15... Inert gas cylinder 16... Conduit 17... Pressure reducing valve 1B... Lid body 19... -Rotating shaft 20...through hole 21...-bearing part 22.23...partition plate 24...ventilation hole 25...input part 26-ventilation part 27--connecting part 28--partition Plate 29... Bearing part 9 0.32... Bevel gear 1... Rotating drive shaft 3... Stamping motor 4.35... Rotating disk 6... Conduit 7... - Outflow pipe 8. 39...-fall hole

Claims (1)

[Claims] (1) In a material supply device for an injection molding machine that supplies synthetic resin material to a heating cylinder of an injection molding machine, the main body of the material supply device, which connects the synthetic resin material supply section to the heating cylinder, is divided into multiple stages, and Each step is connected through a drop hole of the synthetic resin material, and at least one of the steps is connected to an inert gas supply source. Material feeding device for injection molding machine.