JPH0994855A - Injection compression molding machine for molding thermoplastic resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize high cycle operation with low installation cost without increasing manufacturing cost of a machine. SOLUTION: When closing of a mold is completed, a direction switch valve of a mold clamping advancing hydraulic circuit is made neutral and an advancing side oil feeding port of a mold clamping cylinder 71 is connected to a drain circuit. A mold clamping mechanism C for switching a direction switching valve to the advancing side when filling of a set amt. of a molten resin is completed in a mold and a large vol. injection molding mechanism A utilizing an extrusion molding machine are combined and a nozzle provided at the central part of a mold on the fixed side of the mold clamping mechanism and opened in the mold is connected to an outlet 4b of the molten resin in a resin path 21. In addition, the movable side mold is opened by pushing by the pressure of the resin fed into the mold from the nozzle hole and when feeding of the set amt. of the resin is completed, the nozzle hole is closed and the direction switching valve is switched to the advanced side based on a signal for closing to generate a mold clamping force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin molding injection capable of high-cycle processing of large-sized thermoplastic resin products such as forklift pallets, concrete panels or automobile bumpers. The present invention relates to a compression molding machine. In addition, claim 2 is, especially in the field of plastic molding processing by an injection molding machine,
The present invention relates to an injection compression molding machine for molding a thermoplastic resin, which is capable of high-cycle processing of a large-sized molded product several times larger by an inexpensive molding machine with a slight modification.

[0002]

2. Description of the Related Art Conventionally, in molding a thermoplastic resin, an injection molding method has been known as a typical molding method for molding a three-dimensionally complicated shape. As is well known, this molding method melts the thermoplastic resin raw material in order to make the product as thin as possible, to stabilize the dimensional accuracy, and to make a beautiful molded product without sink marks or burrs on the appearance. The molded product is injected into a clamped mold at a high injection pressure and then cooled and solidified in the mold.

Therefore, a mold is required to be robust so as to withstand a high injection pressure, and a molding machine is also required to have a strong mold clamping force capable of withstanding the high injection pressure by clamping the mold. There is.

Generally, according to the catalog specifications of each injection molding machine manufacturer, the injection pressure of an injection molding machine is equipped with an injection mechanism having an output of 1200 to 2500 kg / cm ² regardless of the size of the machine. There is. And in the same machine, the injection pressure and the injection capacity are in inverse proportion to each other, and in order to obtain a beautiful molded product with stable dimensional accuracy as described above, a high injection pressure is required, so only a small molded product is molded. The result was that I couldn't.

As described above, the high injection pressure is required in the conventional injection molding method because the molten resin is completely filled in the mold cavity that has been clamped and cooled, and the sink mark is prevented. This is because the pressure of the resin tries to deal with it.

Further, when molding a large-sized molded product, when the molten resin is injected, the flow length is limited in proportion to the thickness, so that a multipoint pinpoint gate is required.
Therefore, when the thermoplastic molten resin is injected and supplied to the mold cavity space, the molten resin flows in a narrow space with a narrow gate at the same time as the injection is started, and is cooled by the mold. This molten resin has the property of increasing in viscosity as the temperature decreases, and the viscosity increases.

In addition, the high injection pressure in the injection molding machine causes the molten resin to be injected from the thin gate into the wide mold cavity space, and this pressure is dispersed. It takes a long time to fill the resin due to the decrease in pressure.

Therefore, when the mold cavity space is completely filled with the set amount of resin, the molten resin begins to cool and solidify on the surface of the molded product, and a skin layer starts to form on the surface of the molded product.

Further, as described above, since the molten resin becomes highly viscous as the temperature decreases, the flow velocity in the cavity of the mold becomes slow, the heat is rapidly absorbed by the mold, and the thickness of the skin layer is reduced. The molten resin portion of the pressure transmitting portion that increases in number and transmits pressure is reduced. As a result, the pressure-conducting part also becomes narrower, the viscosity of the molten resin increases in the pressure-conducting part, and the force that causes resin shrinkage toward the thickness center of the molded product during cooling is due to the large resistance of the resin flow. It becomes a force and opposes the injection pressure.

Therefore, since the mold acts as a heat exchanger for cooling the molten resin, the effect of preventing sink marks cannot be expected even if ultrahigh pressure is adopted as the injection pressure. Sometimes, it is molded by mixing a foaming agent. However, the foaming gas from the foaming agent appeared as a silver mark on the surface of the molded product, and a flow pattern appeared,
It may spoil the appearance of the surface.

Therefore, recently, a special device for supplying a high-pressure gas with a molten resin to a mold cavity is used to locally generate a void (cavity) inside the thick part of the molded product to prevent the occurrence of surface sink marks. It is the current situation that is struggling with.

As described above, the thermoplastic molten resin becomes highly viscous as the temperature lowers and has a limited fluidity. The thinner the molded product of this molten resin, the shorter the flow length. That is, the flow length is proportional to the thickness. Therefore, in a mold for molding a molded product having a large projected area and a thin wall, it is impossible to prevent the sink mark by filling the mold cavity with molten resin unless a large number of pinpoint gates are arranged. It was a thing.

In addition, in order to reinforce the strength, glass fiber (length 1-2 m
It is often desirable to use m) as a reinforcing composite. However, with a pin-point gate design mold that mixes glass fiber as a composite agent to mold molten resin, gate wear occurs when the glass fiber flows, the gate becomes thick, and the molded product is released from the mold. , I can't cut the gate well. In many cases, a good product cannot be molded due to peeling at the gate part of the molded product or cracks at the gate part of the molded product. For this reason, there is a disadvantage in that a reinforcing composite agent that promotes wear of glass fiber or the like cannot be used in a large-sized molded product having a multipoint pinpoint gate.

As described above, the molten resin of the thermoplastic resin needs to have a high injection pressure because the molten resin increases in viscosity when the temperature decreases even though the resin is supplied and filled in the mold cavity space in a liquid state. Since it is cooled and solidified on the way, a higher injection pressure is required.

Further, the thermoplastic resin has a resin shrinkage due to cooling and solidification, and in order to prevent sink marks due to the resin shrinkage force, the mold is made to have a high rigidity and the mold is tightened with a strong force. Mold clamping force was also needed.

As described above, the conventional injection molding method uses cooling →
This is a molding method that directly opposes the properties of a resin, that is, solidification → resin shrinkage. In addition to this injection molding method, an injection compression molding method is known as a molding method for molding a three-dimensionally shaped molded product.

However, this injection compression molding method is not used for the following reasons.

(1) In the injection compression molding method, for example, a molded product having a large number of small meshes, such as a household colander, has a structure in which the small meshes are burred by compression to form a mesh. I can't.

(2) The injection compression molding method is not suitable for molding a molded product, such as a bobbin, which cannot be molded unless the mold of the product is designed to have a split mold structure.

(3) In the case of forming a plurality of molded products by running a runner and supplying a molten resin to the molded product by a side gate, the molded product and the runner, gate, etc. Since the resin passage is processed, burrs are generated, which is not suitable for molding. However, with hot runners such as caps for bottle containers, it is possible to form molds that can take several times as many molds as pinpoint gates and other molds with an injection compression molding machine with the same clamping force as the injection molding machine. There are advantages.

As described in (1) and (2) above, there are molded articles that are completely unsuitable for the conventional injection compression molding method, and (3)
, Which has both advantages and disadvantages, and is unsuitable for the conventional injection compression molding method, the unsuitable products occupying in the plastic molding industry are about 40% at most even the operating rate of the molding machine. .

Since it is possible to mold about 40% of these by the injection molding method, the idea that a three-dimensional molded article can be molded only by the injection molding method becomes a common sense contrary to the reality. The injection molding machine manufacturer did not pay attention to the injection compression molding method, and neglected the development efforts of the injection compression molding machine.

For example, in the case of a molded product in which orientation distortion occurs and the molded product is deformed, it is necessary to calculate the projected area of the molded product, and when a mold clamping force of 110 t is required, the mold clamping force is about 100 t. Is set. Then, when the molten resin is injected, the mold opens with its flow pressure, and at the same time as the filling is completed, the mold clamping force applied to this mold automatically becomes the average compression force over the entire surface, and the resin cooling → shrinking process occurs. It acts on a resin as the process progresses. In this way, the compression force due to the mold clamping force acts on the resin in the process of resin cooling → contraction, so that the mold clamping force can be small. As a result, the molecular orientation generated during the filling process is relaxed during mold clamping, and a molded product with no orientation distortion is obtained. This is a remarkable effect using the conventional injection compression molding method. It was an effect.

That is, as described above, the molten resin, which is weighed in the same weight as the molded product, is injected at a high injection pressure into the mold cavity to which the high-pressure mold clamping force is applied, and the product of the projected area and the injection pressure is calculated. When it becomes larger than the mold clamping force (the number of mold clamping t), the mold closed slightly opens. While the molten resin is cooled and solidified in the mold, the initial mold clamping force remains pressed, so the process of filling the molten resin in the mold cavity, cooling shrinkage, and solidification is performed. Is pressurized. So,
As described above, the molecular orientation generated in the process of filling the mold cavity is relaxed during the mold clamping, which is a molding method characterized in that a molded product having no orientation distortion can be obtained. The molding method was used only for the intended molded product.

Therefore, it is common knowledge that the conventional injection compression molding method is a molding method which is less frequently used and has less merit. And for any large molding, an expensive injection molding machine and an expensive mold with high rigidity are required, and it is common knowledge that molding is impossible unless high injection pressure and high mold clamping force are applied. Has become.

Therefore, since the resin for large-sized molded articles does not progress and the injection molding is used, the recycled raw material of industrial waste cannot be used as it is, and the recycling of industrial waste progresses. It is also the biggest cause.

In order to promote the recycling of industrial waste, a pallet mold for a forklift mounted on a conventional vertical mold clamping mechanism is opened up and down, and a lower mold upper surface is disclosed in Japanese Patent Publication No. 7-63997. The nozzle of the publication is taken in and out, the molten resin is injected and supplied, and the resin is compression-molded by the mold clamping operation.

[0028]

The number of mold clamping of the mold clamping mechanism in the large-capacity injection mechanism disclosed in Japanese Patent Publication No. 7-63997 disclosed by the inventor of the present application is also the same as the projected area of a conventional injection molding machine. It is only a little less than 1/5 of the number of t required in. Besides, the machine price is also higher than the conventional injection molding machine.
It has the advantage that it can be provided at a significantly low price and that the molding cycle can be molded in the same cycle as the conventional injection molding machine, which is a satisfactory molding machine.

However, since a large mold is required for a large molded product, the mechanical structure also becomes large, and there is a drawback that a loss time is generated by the operation of moving the nozzle at the tip of the injection mechanism in and out.

Also, in the case of a large molded product, there is a problem that cold marks (patterns due to the temperature difference of the molten resin supplied to the upper surface of the lower mold) appear on the surface of the molded product, but in the case of a forklift pallet, There is another step and there is no support. However, in order to form a molded product with a beautiful appearance equivalent to that of an injection molding machine, this cold mark will not occur unless the molten resin is brought into contact with the cavity surfaces of the fixed-side mold and the movable-side mold and allowed to flow. There was a problem that it could not be stopped.

The present invention is an injection compression molding for thermoplastic resin molding capable of high cycle production at a low equipment cost for moldings other than moldings which are not suitable for injection compression molding of about 40% at the molding machine operating rate. The purpose is to provide a machine.

Further, the present invention is applicable to the large-capacity injection molding mechanism A of Japanese Patent Publication No. 7-63997 or a conventional injection molding machine which can obtain a stable plasticizing temperature and kneading degree with recycled raw materials which are all crushed. It is possible to provide an injection compression molding machine for molding a thermoplastic resin, which is capable of molding a larger molded product without a loss time without increasing a machine manufacturing cost by using a capacity increasing injection molding mechanism D provided with an injection measuring cylinder. To aim.

Further, according to the present invention, the nature of the resin such as cooling → solidification → resin shrinkage is naturally compressed so that the compression effect becomes remarkable, the pressure effectively acts, and the filling is performed even at a low filling pressure. It is an object of the present invention to provide an injection compression molding machine for molding a thermoplastic resin capable of molding.

In addition, since the molten resin flows in a thick state as compared with the conventional injection molding, the injection pressure molding machine for thermoplastic resin molding is less affected by the mold temperature and the injection pressure is low. The purpose is to provide.

Furthermore, since the influence of the mold temperature is small in preventing sink marks due to shrinkage when the molten resin is cooled and then solidified, the resin temperature does not decrease, and the thick wall portion of the molded product or the rising structure portion (for example, It is an object of the present invention to provide an injection compression molding machine for molding a thermoplastic resin, which is pressed evenly over the entire area of the back ribs, rod-shaped projections, etc. and can be molded even when the mold clamping pressure is low.

[0036]

In order to solve this problem, the present invention provides a mold clamping cylinder by switching the mold clamping forward hydraulic circuit directional switching valve to neutral when the mold closing of the mold is completed. The forward side oil supply port is connected to the drain circuit, the mold clamping forward hydraulic circuit is kept in a non-pressure state, and the molten resin is supplied into the mold closed.

As a result, the movable side mold is retracted, and only when the mold clamping mechanism is the horizontal mold, a throttle valve is provided between the direction switching valve and the drain circuit connected at the time of neutral, and the mold clamping forward hydraulic circuit at the time of supplying molten resin. Is a hydraulic circuit that can adjust the back pressure.

Then, when the set amount of the molten resin is filled in the cavity space of the mold, the direction switching valve is switched to the forward side to form a mold clamping mechanism for generating a high pressure.

This mold-clamping mechanism and an extrusion-molding machine of Japanese Patent Publication No. 7-63997 relating to the invention of the present inventor in which a measuring cylinder is slidable with respect to a fixed piston into which an extrusion-molding screw is inserted are used. Combine with a high-capacity injection molding mechanism.

At the center of the fixed mold of the mold clamping mechanism, there is provided a nozzle that opens into the mold cavity space where the mold is closed.

A resin passage is provided between this nozzle and the molten resin outlet of the large-capacity injection molding mechanism, and the thermoplastic molten resin is pressure-free or pressure-free when the mold is closed by the nozzle hole of this nozzle. Press-fit and supply into the close mold cavity space.

The pressure of the supplied resin causes the movable side mold to be pushed open from the fixed side mold, the molten resin is allowed to flow into the mold cavity space without resistance, and when the supply of the set amount of resin is completed, The nozzle hole is closed, the backflow of the molten resin in the mold cavity space is prevented by the mold clamping force, and the direction switching valve in the neutral state is switched to the forward side by the closing completion signal.

In this way, a mold clamping force is generated in the mold clamping mechanism, and the mold is clamped to a predetermined thickness.

Also in the case of modification of the conventional injection molding machine, when the mold clamping mechanism of the conventional injection molding machine is closed, the high pressure is maintained even if the mold clamping forward hydraulic circuit is switched to neutral. It was. When the mold closing of the mold is completed, the mold clamping forward hydraulic circuit directional control valve is switched to neutral so that the advance side oil supply port of the mold clamping cylinder is connected to the drain circuit. Then, the mold clamping forward hydraulic circuit is set to a non-pressure state, and the molten resin is supplied into the mold closed to retract the movable mold, and the direction switching is performed only when the mold clamping mechanism is the horizontal mold. A throttle valve is installed between the valve and the drain circuit that is connected when in neutral, and the mold clamping forward hydraulic circuit is a hydraulic circuit that can adjust the back pressure when supplying molten resin. The mold clamping mechanism is modified so that high pressure is generated by switching the directional switching valve to the forward side when the set amount of the molten resin is completely filled in the cavity space of the mold.

The injection cylinder of a conventional injection molding machine has a large inner diameter and is provided with a measuring cylinder that has the same stroke and enables the same stroke as that of the injection molding machine. Provide a screw head that fits in the cylinder.

The screw head is divided into a screw head distal end and a screw head proximal end so as to be freely connectable, and the distal end portion of the screw head proximal end has a small diameter, and a backflow preventing ring valve is provided in this small diameter portion.

The valve seat for the ring valve is formed at the base end of the small diameter portion, and the tip end of the screw head is formed as a tapered taper portion which is fitted into the tapered taper hole of the measuring cylinder head, and the ring valve for the backflow prevention is provided around it. It was combined with a volumetric injection molding mechanism that provided a screw head resin passage groove connected to the outlet.

[0048]

BEST MODE FOR CARRYING OUT THE INVENTION An injection compression molding machine for molding a thermoplastic resin according to an embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows that when the mold closing is completed, the mold clamping forward hydraulic circuit directional switching valve is set to neutral to connect the advance side oil supply port of the mold clamping cylinder to the drain circuit and when the set amount of molten resin is filled. An injection compression molding machine for thermoplastic resin molding, which is a combination of a mold clamping mechanism with the switching valve on the forward side and a large-capacity injection molding mechanism using an extrusion molding machine, is shown. FIG. 2 shows an outline of an example of a mold clamping forward hydraulic circuit of the mold clamping mechanism, and FIG. 3 shows an outline of a large capacity injection molding mechanism.

FIG. 4 is a vertical cross-sectional view of the upper and lower molds in a vertical arrangement in which the lower mold of the forklift pallet is the fixed mold, and FIG. 5 is a sectional view taken along line V-V of FIG. It is shown.

FIG. 6 is a central longitudinal section of only the fixed side mold in the case of a molding machine in which the resin passage of the injection mechanism and the nozzle are provided on the fixed side in the horizontal mold clamping mechanism in which the mold clamping mechanism and the injection mechanism operate in-line. It is a front view.

FIG. 7 shows an increased capacity injection molding mechanism in which an injection measuring cylinder having a diameter larger than this cylinder is attached to the tip of the injection cylinder of a conventional injection molding machine. FIG.
Shows a nozzle structure of a horizontal mold clamping mechanism in which the mold clamping mechanism and the injection mechanism of FIG. 7 operate in-line.

Reference numeral A shown in FIG. 1 is a large-capacity injection molding mechanism using the extruder of Japanese Patent Publication No. 7-63997 according to the invention of the present inventor. Recycled raw materials from the hopper B are shown in FIG. It is supplied to a heating cylinder 1 with a built-in extrusion screw 2. The screw 2 is rotatably inserted into the tip of the heating cylinder 1, and a fixed piston 3 fixed to the tip of the extruder cylinder (heating cylinder 1) is provided. A measuring cylinder 4 into which the fixed piston 3 is inserted is provided, and the fixed cylinder 3 is slidable by a hydraulic cylinder, and molten resin from the heating cylinder 1 is charged into the measuring cylinder 4 from the tip of the fixed piston 3. Then, the measuring cylinder 4 is slid forward together with the charge of the molten resin, and when the charging is completed, the measuring cylinder 4 is slid backward along the fixed piston 3 by the hydraulic cylinder to remove the molten resin in the measuring cylinder 4. It is pressed by the fixed piston 3 and supplied to the nozzle arm (resin passage) 5 from the molten resin outlet 4b.

Reference numeral C is a vertical mold clamping mechanism, which is a lower fixing table 6.
The upper movable table 7 is moved down by the five mold clamping cylinders 71, and the upper movable table 7 is moved up by the two lifting cylinders 8. Then, the upper mold 9 mounted on the upper movable table 7 is pressed against the lower mold 10 mounted on the lower fixed table 6 to clamp the mold.

This vertical mold clamping device C has a mold clamping forward hydraulic circuit direction switching valve for the mold clamping cylinder 71, as shown in FIG. 2, at the time when the upper and lower molds 9 and 10 are completely closed. 72 is switched to neutral, and the advance side oil supply port of the mold clamping cylinder 71 is connected to the drain circuit. And
When the cavity spaces of these molds have been filled with the set amount of the molten resin, the direction switching valve 72 is switched to the forward side, the nozzle 20 described later is closed, and the supply of the molten resin is stopped.

The upper and lower molds 9 and 10 are molds for a pallet for a forklift, and the mold mounting plate 11 of the lower mold 10 on the fixed side is fixed to the lower fixing base 6 of the vertical mold clamping mechanism C to be movable. The mold mounting plate 12 of the upper mold 9 on the side is fixed to the upper movable table 7 of the mold clamping mechanism C.

In this lower mold 10, an outer frame 16 is arranged on a pressure receiving plate 14 attached to a lower mold mounting plate 11 via a plurality of support pillars 13 to provide a female mold cavity 15. And constitutes the mold cavity space 151.

A plurality of ejector pins 17 are inserted into the pressure receiving plate 14, the base end of each ejector pin 17 is fixed to the ejector plate 171, and the ejector plate 171 is pushed up to project the molded product. .

The upper mold 9 is provided with a male mold cavity 18 on the lower surface of the mold mounting plate 12, and the upper mold 9 is clamped on the lower mold 10. At the time of this mold clamping, the stopper pin 19, on the outer frame 16 of the lower mold 10,
19 is provided, the fitting degree of the male and female cavities 15 and 18 is adjusted, and the thickness of the molded product is determined.

A nozzle 20 opening to the mold cavity space 151 is provided in the lower center of the lower mold 10, and a heater 211 is provided around the nozzle 20 and the nozzle arm (resin passage) 5 of the large-capacity injection molding mechanism A. It connects with the resin passage 21. Then, the molten resin is supplied from the nozzle arm 5 to the mold cavity space 151 between the cavities 15 and 18.

Here, the ejector plate 171 for pushing up the ejector pin 17 is provided with a cutout 172 for passage of the resin passage 21 connected to the nozzle 20 provided at the lower center of the lower mold 10 and a circular support pillar 13 at the center. A through hole 173 for insertion is provided.

The nozzle 20 is opened / closed by inserting / removing the valve rod 203 into / from the nozzle hole 201 by a nozzle valve actuating actuator 202 provided in the lower portion of the nozzle 20.

The structure of the nozzle 20 may be any structure as long as it is a valve nozzle used in a general injection molding machine. However, in this large capacity injection molding mechanism A, the injection pressure is small, so that the molten resin is used. It is preferable that the structure has a small flow resistance and a large nozzle diameter. The nozzle structure in which the spring is mounted inside the nozzle is inadequate because the operation becomes inaccurate due to the flow resistance of the molten resin.

The nozzle 20 is preferably a valve nozzle (shut-off nozzle) having the above-mentioned structure that can be externally operated by air pressure or hydraulic pressure and is not affected by heat.

In using this, the molten resin is press-fitted into the mold cavity space 151 of the upper and lower molds 9 and 10 in which the vertical mold clamping mechanism C has completed the mold closing from the nozzle hole 201 of the large capacity injection molding mechanism A. Supply. At this time, the mold clamping mechanism C is in neutral, and the mold clamping cylinder 7
Since the forward drive side oil supply port of No. 1 is connected to the drain circuit, the mold clamping force is in a state of no pressure or almost no pressure, and the movable side mold 9 is attached to the mold mounting plate 1 by the resin pressure that is press-fitted and supplied.
Push it open against the weight of 2nd class. Then, when the set amount of the molten resin measured by the measuring cylinder 4 is supplied to the mold cavity space 151, the mold clamping force is in the state of no pressure or close to it, so that the molten resin has a low resistance to the mold. It flows into the cavity space 151. Then, the movable mold 9 is supplied with a set amount of molten resin and opens to a predetermined position, and the movable mold 9 automatically stops.

In the vertical mold clamping mechanism C, the lower mold 1
If 0 is the fixed side, or if it is a large molded product such as a pallet for a forklift, the total weight of the upper mold 9 and the movable side mechanism such as the mold mounting plate 12 of the mold clamping machine is about 5. ~ 6t
It will be about the weight. However, if the pressure of the molten resin supplied from the central portion of the lower mold 10 is about 50 to 60 kg / cm ^2, when it is supplied to the mold cavity space 151 in an area of about 20 cm in diameter, the upper mold 9 Begins to rise, so
The intended purpose is achieved.

Even in the case of a super-large molded product such as a resin pallet, the molten resin is injected into the mold cavity spaces 151 of the upper and lower molds 9 and 10 by injecting the molten resin from one place in the center of the molded product. Supply is possible.

Next, the molten resin is allowed to flow into the mold cavity space 151 without resistance, and the set amount of molten resin is completely supplied between the movable side mold 9 and the fixed side mold 9, 10 which are opened at a fixed position, and at the same time, the nozzle valve. Actuator for operation 202
Activate Then, the actuator 202 inserts the valve rod 203 into the nozzle hole 201 to close the passage of the molten resin.

The closing of the nozzle hole 201 prevents the backflow of the molten resin from the mold cavity space 151 by the mold clamping force.

At the same time when the nozzle hole 201 is completely closed,
In response to the closing completion signal, the mold clamping forward hydraulic circuit direction switching valve 72 in the neutral state is switched to the forward side to cause the mold clamping mechanism C to generate a mold clamping force, and the mold is clamped to a predetermined thickness.

FIG. 6 shows a mold structure when the upper mold of the vertical mold clamping mechanism is a fixed mold or when a molding machine of a horizontal mold clamping mechanism in which the mold clamping mechanism and the injection mechanism are operated inline is used. It shows a fixed side mold. In the case of the horizontal mold clamping mechanism, the upper mold 9 arranged vertically and the lower mold 10 shown in FIG. 4 are arranged laterally with the lower mold 10 being the movable side. Becomes the vertical direction,
It opens to the left and right. In this case, even if it is injected from a single nozzle hole 201 of the same nozzle 20 provided in the central portion of the fixed-side mold 10, the molten resin not only in the horizontal direction but also in the vertical direction maintains a circular shape with a radially averaged radius. While flowing,
A good molded product can be obtained. Further, in this case, a throttle valve 73 is provided between the direction switching valve 72 and the drain circuit connected at the time of neutral, and back pressure is applied to the mold clamping cylinder 71 to eliminate the vertical flow difference.

Further, FIG. 7 shows a conventional injection molding machine with an increased volume injection molding equipped with an injection measuring cylinder 23 having an inner diameter larger than that of the injection cylinder 22 and enabling the same stroke as the injection molding machine. The mechanism D is shown. Further, a mold clamping mechanism obtained by modifying the mold clamping mechanism of the conventional injection molding machine in the same manner as the vertical mold clamping mechanism C of claim 1 is provided behind the nozzle 20.

The conventional injection molding machine is provided with a screw 24 which is inserted into the cylinder 22 and rotates. When the tip of the screw 24 is charged with molten resin, the screw 24 is moved to the cylinder 22 by the volume. Go back inside.

The injection measuring cylinder 23 having a large inner diameter is
The inner diameter of the injection cylinder 22 is continuously fixed to the tip of the injection cylinder 22, and the inner diameter is, for example, twice the inner diameter of the injection cylinder 22. By doing this, for example, 70
The injection amount of cc is the calculated value, which is four times as large as the injection amount of 280 cc. Of course, the injection stroke of the increased-capacity injection molding mechanism D is the stroke of the conventional injection molding machine, and the injection pressure is 1/4. With the injection pressure and the mold clamping force equipped in the conventional injection molding machine, it becomes possible to mold a molded product having a projected area several times as large as the conventional size.

The injection pressure of the conventional injection molding machine is 1 /
Even if the value becomes 4, the injection pressure has a sufficient reserve capacity for the injection compression molding of the present invention. Further, the rotational torque of the screw 24 for the resin plasticizing charge does not require much rotational torque because only the torque required for the screw head 25 described later to rotate in the molten resin is added.

Further, in the case of the conventional injection molding machine, even if the mold cavity space 151 is completely filled with the molten resin, injection pressure is applied until the gate is cooled and solidified in order to prevent sinking of the molded product. I had to. Therefore, during that time, it was not possible to measure the plasticization of the resin by rotating the screw, so it took a long time for each cycle. However, similar to the large-capacity injection molding mechanism A, the increased-capacity injection molding mechanism D also uses the molten resin for the molds 9 and 1.
The resin can be plasticized and measured upon completion of the supply to the mold cavity space 0 of 0, and a long cycle can be realized without requiring a long time for each cycle.

A screw head 25, which has a diameter slightly smaller than that of the injection measuring cylinder 23 and can be inserted into the cylinder 23, is provided, and a male screw 251 formed at the base of the screw head 25 is formed at the tip of the screw 24 to form a female screw 241. Screw into.

This screw head 25 is divided into a front end 252 and a base end 253 in the middle, and the screw head front end 2
A male screw 254 formed at the base end of 52 is screwed into a female screw 255 formed at the tip of the screw head base end 253 to allow connection. And the screw head base end 2
The tip portion of 53 has a small diameter, and the backflow prevention ring valve 26 that is inserted into the cylinder 23 and slides is provided in the small diameter portion 256. The valve seat 257 is formed.

The tip of the screw head tip 252 is made to be a tapered taper portion 258 which is fitted into the tapered taper hole 232 of the injection weighing cylinder head 231 fixed to the tip of the injection weighing cylinder 23. Then, an annular outlet 26 constituted by the small-diameter tip portion of the screw head base end 253 and the inner surface of the tip portion of the backflow prevention ring valve 26.
A screw head resin passage groove 259 connected to the No. 1 is provided around the tapered portion 258.

A nozzle 2 similar to the above, which is fixed to the tip of the injection measuring cylinder head 231 with a nozzle fixing flange 204.
0 is provided in the L-shaped arrangement of the injection cylinder 22 of the injection molding machine and the modified mold clamping mechanism. Then, similarly to the above, the valve rod 203 is inserted into and removed from the nozzle hole 201 by the nozzle valve actuating actuator 202 provided in the rear portion of the nozzle 20 to open and close.

FIG. 8 shows a nozzle structure of a horizontal mold clamping mechanism in which the injection mechanism of FIG. 7 and a modified mold clamping mechanism are operated inline. The nozzle 20 is linear (inline) with the injection cylinder 22 of the injection molding machine. ) -Shaped. In this case, since it is impossible to provide the nozzle valve actuating actuator 202 and the valve rod 203 which are opened and closed by being inserted into and removed from the nozzle hole 201, instead,
A rotary valve 27 for opening and closing the nozzle is attached. Also in FIG. 6, if it is desired to use the nozzle structure shown in FIG. 7, the injection mechanism may be arranged in an L-shape with respect to the mold clamping mechanism.

In using the combination of the modified mold clamping mechanism and the increased volume injection molding mechanism D, the screw 24 in the injection cylinder 22 of the injection molding machine is rotated, and the plasticized molten resin is removed. 7 is transferred in the direction of the arrow. At this time, the backflow prevention ring valve 26 is pressed against the base end of the screw head tip 252 by the charge pressure of the molten resin.
Is separated from the valve seat 257 for the ring valve, and the ring valve 26
Is open. Then, the molten resin is accumulated from the annular outlet 261 through the screw head resin passage groove 259 and between the tapered taper portion 258 of the screw head tip 252 and the tapered taper hole 232 of the measuring cylinder head 231.

Tapered taper portion 258 and tapered taper hole 232
The screw head tip 25 due to the molten resin stored between
2 retracts with screw 24. Then, when the molten resin is charged by a set stroke out of all strokes L of the conventional injection molding machine, the screw 2
When the rotation of No. 4 is stopped and the injection is started, the backflow prevention ring valve 26 comes into contact with the ring valve valve seat 257 of the screw head base end 253 by the injection pressure.

The molten resin charged in the injection measuring cylinder 23 is prevented from flowing backward by the backflow preventing ring valve 26 until the screw 24 advances and the injection is completed.

The injected molten resin is press-fitted and supplied from the nozzle hole 201 of the nozzle 20 into the mold cavity space 151 of the mold clamping mechanism modified in the same manner as described above, and this resin pressure causes the movable mold 9 to move in the same manner as described above. Push and open against the weight of the mold mounting plate 12, etc.

Then, the molten resin comes into contact with the inner surfaces of the slightly opened mold cavity spaces 151 of the upper and lower molds 9 and 10 closed by the mold clamping mechanism, and the molds 9 and 1 having a low resistance.
Flows radially from the nozzle hole 201 to the inner surface of 0, maintaining a circular shape with an average radius length, and widening the area.
The injection pressure of the injection compression molding machine according to the present invention is about 10% of the injection pressure of the conventional injection molding method, even if the melt-measured resin amount is several kg to several tens kg. It can be ejected in a short time.

Further, by the operation of the direction switching valve 72 for switching the non-pressurized state of the mold clamping forward hydraulic circuit to the forward direction, a mold clamping force is generated and high pressure mold clamping is performed up to a predetermined thickness of the molded product. As for the required mold clamping pressure, compared to the conventional injection molding method, if the same molded product has a mold clamping pressure of about 20%, a satisfactory molded product can be obtained.

Furthermore, in the injection compression molding machine of the present invention, even if the diameter of the nozzle 20 is large and the molded product has a large projected area,
Since the nozzle hole 201 is injected at the same time as the injection of the molten resin from the center of the mold and the supply of the molten resin is completed, even if the supply port of the mold is worn, regardless of the mold release, the glass is used as a composite agent. Even if fibers are mixed, the nozzle 20 is less worn,
The use of reinforcing composites is also free.

[0089]

The large-capacity injection molding mechanism A using an extruder and the mold clamping forward hydraulic circuit directional control valve is switched to neutral when the mold closing is completed, and the advance side oil supply port of the mold clamping cylinder is changed to the drain circuit. By combining with a mold clamping mechanism C that connects the valves and switches this valve to the forward side when the set amount of molten resin is completely filled, a large molded product of several 10 kg can be molded with an inexpensive molding machine and a mold. .

In the injection compression molding machine in which the large-capacity injection molding mechanism A and the mold clamping mechanism C are combined, the plastic which has been regarded as industrial waste is recycled and the composite agent such as glass fiber is used. A molded product having higher mechanical strength can be molded. In addition, in the conventional injection molding method,
It has been difficult to manufacture a molded product in which a hinge (a portion in which a linear ultra-thin recessed portion is formed and can be bent like a hinge) is formed. However, in the injection compression molding machine of the present invention, regardless of whether the hinge portion is long or short, and the number of hinges is any, since the compression is performed after the molten resin is flowed into the mold, molding is not performed. It will be easy. Also, three-dimensional three-dimensional products, such as home apparel boxes, can be assembled by bending the hinge, and the mold can be a simple mold such as a flat development view.
The molded product also becomes flat, and transportation and storage costs can be significantly reduced.

The present invention, the transportation cost, which has been soaring in recent years,
In order to reduce storage costs, it is expected that the number of product designs that make extensive use of this type of hinge will increase dramatically, but it is possible to sufficiently cope with such social trends.

Furthermore, the injection compression molding machine which is a combination of the increased-capacity injection molding mechanism D using the injection mechanism of the conventional injection molding machine and the modified mold clamping mechanism has an output of the original injection molding machine, that is, a motor horsepower. As it is, it is possible to mold a large molded product having several times the weight and projected area.

In this injection compression molding machine using the conventional injection molding machine, the plastic waste material requires pelletization by an extruder as a pre-process, and there are few places that contribute to plastic recycling, but it is small. A large-capacity molded product can be molded with a high-capacity injection molding machine, and an injection compression molding machine can be manufactured at low cost.

Further, the injection compression molding machine with this increased capacity requires a low injection pressure, the modified mold clamping mechanism requires a mold clamping force as low as about 20% of that of the conventional injection molding method, and the mold has a high mold. Rigid ones are not needed and the cost is low.

In recent years, the trend of the world has changed from mass production to mass consumption, and various kinds of products have been manufactured. Various products have been developed. In order to make them into resin, gold as an initial cost is required. Although it is required to reduce the price of the mold, the injection compression molding machine of the present invention can meet the demand.

Since the injection compression molding machine of the present invention has a low injection pressure and a low mold clamping force and low-pressure molding, an aluminum mold can be used to mold a sufficiently large molded product.

The use of the injection compression molding machine of the present invention makes it possible to support high-value-added products in high-mix low-volume production, and to give activity to the plastic molding industry and its related industries, which are undergoing hollowing out of industry. It is a great motivation to develop and contribute to this kind of industry.

[Brief description of drawings]

FIG. 1 is a combination of a mold clamping mechanism in which a mold clamping forward hydraulic circuit valve is set to neutral when mold closing is completed, and is set to advance side when molten resin filling is completed, and a large-capacity injection molding mechanism using an extruder. It is a side view of an injection compression molding machine for thermoplastics molding.

FIG. 2 is a schematic piping diagram showing an example of a mold clamping forward hydraulic circuit of the mold clamping mechanism of FIG.

FIG. 3 is a lateral cross-sectional view of the center of a main part showing an outline of a large-capacity injection molding mechanism.

FIG. 4 is a central vertical cross-sectional view of upper and lower molds in a vertical layout in which a lower mold of a forklift pallet is a fixed mold.

FIG. 5 is a sectional view taken along line VV of FIG. 4;

FIG. 6 is a fixed side in the mold structure when the upper mold of the vertical mold clamping mechanism is a fixed mold, or when a molding machine of a horizontal mold clamping mechanism in which the mold clamping mechanism and the injection mechanism operate is used. It is a central longitudinal cross-sectional view of a mold.

FIG. 7 is a schematic view of a high-capacity injection molding mechanism in which an injection measuring cylinder is attached to the tip of the injection cylinder of a conventional injection molding machine, and a main part in which the injection mechanism is arranged in an L shape with respect to the mold clamping mechanism. It is a central longitudinal cross-sectional view.

FIG. 8 is a central longitudinal cross-sectional view showing the outline of a nozzle structure of a horizontal mold clamping mechanism in which the mold clamping mechanism and the injection mechanism of FIG. 7 operate in-line.

[Explanation of symbols]

 1 Heating Cylinder 2 Extrusion Molding Screw 3 Fixed Piston 4 Measuring Cylinder 4b Molten Resin Outlet 5 Nozzle Arm (Resin Passage) 6 Lower Fixed Platform 7 Upper Movable Platform 71 Mold Clamping Cylinder 72 Mold Clamping Forward Hydraulic Circuit Valve 73 Throttle Valve 8 Ascending Cylinder 9 Upper mold 10 Lower mold 11 Lower mold mounting plate 12 Upper mold mounting plate 13 Support pillar 14 Pressure receiving plate 15 Female cavity 151 Mold cavity space 16 Outer frame 17 Ejector pin 171 Ejector plate 172 Notch 173 Through hole 18 Male Mold cavity 19 Stopper pin 20 Nozzle 201 Nozzle hole 202 Nozzle valve actuating actuator 203 Valve rod 204 Nozzle fixing flange 21 Resin passage 211 Heater 22 Injection cylinder 23 Injection weighing cylinder 231 Injection weighing series Under head 232 Tapered taper hole 24 Screw 241 Female screw 25 Screw head 251 Male screw 252 Screw head tip 253 Screw head base end 254 Male screw 255 Female screw 256 Small diameter part 257 Ring valve valve seat 258 Tapered tapered part 259 Screw head resin passage groove 26 Reverse flow Ring valve for prevention 261 Annular outlet 27 Rotary valve for opening / closing nozzle A Large-capacity injection molding mechanism B Hopper C Vertical mold clamping mechanism D Increased volume injection molding mechanism

[Procedure amendment]

[Submission date] April 8, 1996

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0027

[Correction method] Change

[Correction contents]

In order to promote the recycling of industrial waste, a pallet mold for a forklift mounted on a conventional vertical mold clamping mechanism is opened up and down, and the lower mold upper surface has a patent No. 1931933 relating to the invention of the present inventor ( Japanese Patent Examination 6-51331
The nozzle of Japanese Patent Laid-Open Publication No. JP-A-2004-135240 is taken in and out, the molten resin is injected and supplied, and the resin is compression-molded by the mold clamping operation.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0028

[Correction method] Change

[Correction contents]

[0028]

The number of mold clamping t of the mold clamping mechanism in the large-capacity injection mechanism of Japanese Patent No. 1931933 (Japanese Patent Publication No. 6-513331) according to the invention of the present inventor is also as follows.
It is a little less than ⅕ of the t number required in the same projected area molded by the conventional injection molding machine. In addition, the machine price can be offered at a significantly lower price compared to conventional injection molding machines,
Further, the molding cycle has the advantage that molding can be performed in the same cycle as a conventional injection molding machine, which is a satisfactory molding machine.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0032

[Correction method] Change

[Correction contents]

Further, according to the present invention, patent No. 1931933 (Japanese Patent Publication No. 6-51331) is capable of obtaining stable plasticizing temperature and kneading degree by using recycled raw materials which are all crushed.
By using the large-capacity injection mechanism A or the increased-capacity injection molding mechanism D in which a conventional injection molding machine is provided with an injection measuring cylinder, a larger molded product can be molded without increasing the machine manufacturing cost without loss time. An object is to provide an injection compression molding machine for molding a thermoplastic resin.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0039

[Correction method] Change

[Correction contents]

The measuring cylinder is slidable with respect to this mold clamping mechanism and a fixed piston into which the extrusion molding screw of Japanese Patent No. 1931933 (Japanese Patent Publication No. 6-513331) relating to the invention of the present inventor is inserted. It is combined with a high-capacity injection molding mechanism that uses an extruder.

[Procedure correction 6]

[Document name to be amended] Statement

[Name of item to be corrected] 0045

[Correction method] Change

[Correction contents]

An injection measuring cylinder having a large inner diameter and having the same stroke as the injection molding machine of the conventional injection molding machine is connected and provided, and is connected to the screw tip of the injection molding machine to perform injection weighing. Provide a screw head that fits in the cylinder.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0047

[Correction method] Change

[Correction contents]

The valve seat for the ring valve is formed at the base end of the small diameter portion, and the tip end of the screw head is formed as a tapered taper portion which is fitted into the tapered taper hole of the injection measuring cylinder head, and the backflow prevention ring valve is provided around the tapered taper portion. The increased volume injection molding mechanism is provided with a screw head resin passage groove connected to the outlet of, and the modified mold clamping mechanism and the increased volume injection molding mechanism are combined.

[Procedure amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0048

[Correction method] Change

[Correction contents]

[0048]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of an injection compression molding machine for molding a thermoplastic resin according to the present invention will be described below in detail with reference to the accompanying drawings.

[Procedure amendment 9]

[Document name to be amended] Statement

[Correction item name] 0053

[Correction method] Change

[Correction contents]

Reference numeral A shown in FIG. 1 is a large-capacity injection molding mechanism using the extruder of Japanese Patent No. 1931933 (Japanese Patent Publication No. 6-513331) according to the invention of the present inventor.
Recycled raw materials and the like from the hopper B are supplied to the heating cylinder 1 with the built-in extrusion screw 2 shown in FIG. The screw 2 is rotatably inserted into the tip of the heating cylinder 1, and a fixed piston 3 fixed to the tip of the extruder cylinder (heating cylinder 1) is provided. A measuring cylinder 4 into which this fixed piston 3 is inserted is provided, and the fixed piston 3
It is made slidable by a hydraulic cylinder along with, and the molten resin from the heating cylinder 1 is charged into the measuring cylinder 4 from the tip of the fixed piston 3. Then, the measuring cylinder 4 is slid forward together with the charge of the molten resin, and when the charging is completed, the measuring cylinder 4 is slid backward along the fixed piston 3 by the hydraulic cylinder to remove the molten resin in the measuring cylinder 4. It is pressed by the fixed piston 3 and supplied to the nozzle arm (resin passage) 5 from the molten resin outlet 4b.

[Procedure amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0093

[Correction method] Change

[Correction contents]

In the injection compression molding machine using this conventional injection molding machine, the plastic waste material needs to be pelletized by the extruder as a pre-process, and there is a problem that it does not contribute much to the recycling of plastic. there were. On the other hand, the injection compression molding machine using the combination of the increased-capacity injection molding mechanism D according to the present invention and the modified mold clamping mechanism is capable of molding a large molded product with an injection molding machine having a small capacity. Machine can be manufactured at low cost.

Claims (2)

[Claims] 1. When the mold closing of the mold is completed, the mold clamping forward hydraulic circuit directional switching valve is switched to neutral to connect the advance side oil supply port of the mold clamping cylinder to the drain circuit. The circuit is kept free of pressure, and the molten resin is fed into the closed mold to retract the movable mold, and only when the mold clamping mechanism is horizontal, it is connected to the directional control valve at neutral. A throttle valve is installed between the drain circuits, and the mold clamping forward hydraulic circuit is used as a hydraulic circuit capable of adjusting the back pressure when the molten resin is supplied, and the direction switching valve is used when the set amount of the molten resin is completely filled in the cavity space of the mold. Is a mold clamping mechanism that generates high pressure by switching to the advancing side, and this mold clamping mechanism and the fixed pierce with the extrusion molding screw of Japanese Patent Publication No. 7-63997 according to the invention of the present inventor are inserted. Combined with a large-capacity injection molding mechanism that uses an extrusion molding machine with a measuring cylinder slidable with respect to a ton, opening in the mold cavity space closed in the mold central part of the fixed side of the mold clamping mechanism. A nozzle to
A resin passage is provided between the nozzle and the molten resin outlet of the large-capacity injection molding mechanism, and a thermoplastic molten resin is injected through the nozzle hole of the nozzle into a mold closed by the mold clamping mechanism or a mold close to no pressure. It is pressed into the cavity space and the resin pressure is supplied to push the movable side mold open from the fixed side mold so that the molten resin flows in the mold cavity space without resistance, and the set amount of resin is supplied. When this is completed, this nozzle hole is closed, the backflow of the molten resin in the mold cavity space is prevented by the mold clamping force, and at the same time the direction switching valve in the neutral state is switched to the forward side by the closing completion signal. An injection compression molding machine for thermoplastic resin molding, wherein a mold clamping force is generated in a mold clamping mechanism to perform mold clamping to a predetermined thickness of a molded product. 2. In a conventional injection molding machine, when the mold clamping mechanism is closed, the high pressure is maintained even when the mold clamping forward hydraulic circuit is switched to neutral. When the mold closing is completed, by switching the mold clamping forward hydraulic circuit directional control valve to neutral, the forward side oil supply port of the mold clamping cylinder is connected to the drain circuit, and the mold clamping forward hydraulic circuit is set to a no-pressure state. By supplying molten resin into the closed mold, the movable mold is retracted, and only when the mold clamping mechanism is the horizontal mold, a throttle valve is provided between the direction switching valve and the drain circuit connected during neutral, The mold clamping forward hydraulic circuit is configured as a hydraulic circuit capable of adjusting back pressure when the molten resin is supplied, and the directional switching valve is switched to the forward side when the set amount of the molten resin is filled in the cavity space of the mold. Without a modified mold clamping mechanism to generate higher pressure, the injection cylinder of a conventional injection molding machine has a large inner diameter, and a measuring cylinder that enables the same stroke as this injection molding machine is connected and provided. A screw head that is connected to the tip of the screw of the injection molding machine and inserted into the measuring cylinder is provided.The screw head is divided into the screw head tip and the screw head base end so that the screw head can be freely connected. Has a small diameter, a backflow prevention ring valve is provided in this small diameter part, and a valve seat for this ring valve is formed at the base end of the small diameter part, and the tip of the screw head is fitted into the tapered taper hole of the measuring cylinder head. The taper section is tapered, and a screw head resin passage groove connected to the outlet of the backflow prevention ring valve is provided around it. The amount injection mechanism and without the modified mold clamping mechanism and increasing capacity injection mechanism and the thermoplastic resin molding injection compression molding machine according to claim 1, characterized in that a combination of.