JP2000296540A - Plasticizing and injection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasticizing and injection device which is compact and has high resin kneading capability, capable of manufacturing a molding stably. SOLUTION: This plasticizing and injection device of an injection molding machine comprises a plasticizing device having a parabolic head 1 with the outline, which is formed of a combination of a plurality of barabolas, of the cross section of a rotatable parabolic screw formed consisting of a single helical groove or a plurality of helical grooves from the tip center to the foot part, arranged in a barrel forming an inner space so as to make the parabolic head 1 coincide with the screw shape, and an injection device arranged in parallel with or at some angle with the plasticizing device, the resin being plasticized, kneaded and injected by these devices. The plasticizing device has a discharging aperture 8 at the tip of the barrel and at the same time, a charging aperture 9 leading to the parabolic recessed part 15 of the barrel 10 on the side face. Thus a molten resin is structurally packed into a pot 13 while the parabolic face-shape screw is rotated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for plasticizing and injecting a plastic material. It also relates to a kneading device of an extruder.

[0002]

2. Description of the Related Art There are many conventional plasticizing and kneading machines of an injection molding machine by various means. As a typical example, compression deformation of a pellet is performed as shown in FIG. It is divided into a transport unit 24 for transporting the mass (plug), a melting unit 23 for forming a molten circulation flow by frictional heat and transfer heat of the cylinder 25 and the plug, and a melt transport unit 22 for transporting the molten resin to the resin outlet. In-line type single screw 26 is commercially available. Further, the resin material filled into the mold by injection molding is a non-Newtonian fluid and a viscoelastic body in a pressurized and solidified state. Therefore, the amount of movement of the plunger is not proportional to the compressive stress applied to the resin material filled in the mold. Further, the resin material is not excellent in followability of the plunger operation. Thus, it is not easy to control the operation of the plunger by a motor or the like.

[0003]

At present, many injection molding machines have an in-line or screw prepeller type structure. Most of the screws used here are generally straight bar screws. Since the screw of the kneading machine used in the conventional injection molding machine is divided into a resin transporting section, a melting section, and a melt transporting section, a long screw and a cylinder are used, and a long member is required. And a long installation space was required. For this reason, it has been difficult to reduce the size of the device. On the other hand, in the cone type screw 27 of the extruder as shown in FIG. 5, the taper of the screw is constant, and the screw has a constant temperature distribution by the heater 32. It has a structure where the parts are integrated. Therefore, the resin is transported and melted at the vicinity of the hopper inlet behind the screw by the heat of the heater 32 at the same time as the transport, so that the resin inlet is clogged (bridge). Further, the structure is such that a back pressure by the resin is directly applied to the drive shaft 28. Further, in a tapered screw, it is ideal that the viscosity of the resin melted inside is linearly distributed, but the viscosity of the actual molten resin varies in a variety of ways, and the viscosity distribution is not linear. Therefore, a screw shape that approximates the viscosity distribution of the actual molten resin has been required.
If the tip angle of the tapered screw is too steep, the entire length of the screw becomes shorter, but there is a disadvantage that it is difficult to apply a temperature gradient from low to high in the process of applying a temperature for melting the resin. Next, at the rear end of the screw, the diameter is enlarged so much that the tip angle is sharpened. When the resin melts, a high back pressure is created here. As a result, a high thrust force is applied to the bearing portion. For this reason, the size of the bearing portion has been increased and the cost of the apparatus has been increased. The bearing portion has been required to have a structure for reducing the thrust force.

In a pre-plastic molding machine, a material is filled in a cavity of a mold, and in this filling step, there is a pressure holding step in which a plunger pressurizes at a predetermined pressure for a predetermined time.
This is a specific operation process for injection molding. But this behavior has a lot of control challenges. The resin material to be filled is pressurized and is a non-Newtonian fluid and a viscoelastic body in a solidified state. Therefore, the amount of movement of the plunger is not proportional to the compressive stress applied to the resin material filled in the mold. In addition, the resin material is not excellent in followability of operation. Thus, it is not easy to control the operation of the plunger by a motor or the like.

At present, in the pressure-holding step, a method of controlling a plunger and a screw by feeding back a change in resin pressure using a pressure sensor or the like has been adopted. However, accurate control is difficult due to the influence of a ball screw, a timing belt, and the like interposed in the middle. In order to improve the performance of the sensor, it is necessary to install a strong and highly sensitive sensor in a severe environment in order to directly take out the resin pressure. Further, the motor for driving this sensor is also a motor with high accuracy and high sensitivity, and both the sensor and the motor are expensive.

[0006] In order to solve this problem, a method generally referred to as classical control mainly using PID has been used for controlling the pressure-holding step. In addition, Japanese Unexamined Patent Publication No.
278176 proposes a structure using an electromagnetic clutch. Further, a pressure waveform tracking control incorporating a learning function for improving the control ability, a journal of the Japan Society of Precision Engineering, February 1999, page 293, and the like have been proposed. Among them, those using an electromagnetic clutch have problems that they cannot withstand a large torque and that the number of parts increases. In the pressure waveform tracking control using the learning function, the pressure waveform reproducibility is good, but it cannot be said that this directly reflects on the function and appearance of the molded product. The history from plasticization to injection of the resin varies, and it cannot be said that no matter how uniform the pressure waveform is, it will be immediately reflected in the finished product. Controlling the history or process in the plasticizing and injection states in this way is problematic. Therefore, another object of the present invention is to provide a plasticizing / injection device incorporating a new type of control system, separately from the conventional motor-driven injection device.

[0007]

SUMMARY OF THE INVENTION The present invention solves one of the problems described above by reducing the space. Instead of using a long screw or a conical screw in a conventional product, the more the tip is advanced to the surface. A parabolic head 1 having a parabolic surface 2 with a spiral groove 3 having a reduced groove depth is used, and a large taper at the tip enhances the melting efficiency. The present invention provides a kneading screw that is compact, has high kneading efficiency, and is easy to clean by combining the parabolic head 1 with the barrel 11 having a parabolic recess. Also, a non-linear viscosity distribution of the molten resin that cannot be obtained with a linear taper screw is realized. Further, in order to obtain a smooth molten state of the resin, the temperature distribution from the resin inlet to the screw tip is gradually raised.

That is, the present invention provides a rotatable parabolic head 1 having a spiral groove 3 formed from the center of the tip of the parabolic surface 2 to the skirt, and a parabolic surface 2 of the parabolic head 1 at the center of the barrel 11. And a discharge port 9 is provided at the tip of the parabolic recess, and an inlet 10 communicating with the parabolic recess 16 of the barrel 11 is formed on a side surface of the parabolic recess. The kneaded material is discharged from the discharge port 9 by charging the material to be kneaded from the charging port 10 while rotating the parabolic surface 2 of the head 1 and the parabolic concave portion of the barrel 11 while maintaining a small interval. I tried to make it. This is a kneading screw for a kneading machine, which realizes a non-linear viscosity distribution of the molten resin that cannot be obtained with a linear taper screw. In addition, a plasticizing / injection device with a structure in which the thrust load due to the back pressure of the resin does not apply a load to the drive source 6

Further, in addition to the structure of the plasticizing device, in the conventional motor driven injection device, the control target of the speed and the pressure is switched based on the torque detection current of the motor. At this time, a plasticizing / injection apparatus incorporating a structure that sets a time correspondence program for predicting a control target in controlling the switching timing and speed / pressure set values and uses a torque detection voltage of a ball screw as a starting reference.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
A description will be given based on FIG. FIG. 1 shows a parabolic head having a parabolic shape having an output shaft 5 driven by a drive source 6 via a coupling 4 on the back surface. As shown in FIG. 3 are formed.

As a material of the parabolic head 1, a structural steel (SCM440H) having excellent seizure resistance and scoring characteristics by surface quenching and quenching is used.
This parabolic head has a temperature control
A band heater is attached to the barrel 11, and the temperature can be adjusted according to the kneading conditions of the material to be kneaded.

The shape, cross-sectional shape and number of the spiral grooves 3 of the parabolic head 1 are not particularly limited, and are appropriately selected according to the properties of the material to be kneaded.
Desirably, the shape is not linear, and the cross-sectional shape is designed so that the parabolic shape gives an ideal viscosity distribution in kneading the resin material.

In the figure, reference numeral 11 denotes a cylindrical barrel (hereinafter referred to as a "barrel") having a parabolic concave portion 16 at the center of one side surface which matches the parabolic surface 2 of the parabolic head 1 and a discharge at its tip. An outlet 9 is provided, and an upper portion has an input port 10 leading to a parabolic recess 16.

The material of the barrel 11 is a metal steel material (SCM440) excellent in seizure resistance and galling characteristics by performing surface nitriding and quenching similarly to the above-mentioned parabolicer 1.
H) is used, and by making the barrel cylindrical, heat transfer from the band heater attached to the barrel 11 to the parabolic head is made uniform.

Further, a heat sink 18 is provided at the input port of the barrel 11 to cool the resin from reaching the parabolic recess 16 from the hopper 8 by its own weight so as not to cause bridging due to rapid heating. is there.

FIG. 2 is a diagram showing the overall configuration of the kneader according to the present invention.
And the housing 17 and the manifold block A12
To fix the parabolic surface 2 of the parabolic head 1 to the parabolic concave portion 16 of the barrel 11, and the cylindrical portion at the rear of the parabolic head is pressed into the bearing 19. The output shaft 5 is connected to the center of the cylindrical portion via a coupling.

Parabolic head 2 and barrel 1 of parabolic head 1
The distance from the first parabolic recess 16 is usually set to about 0.4 mm, but this gap can be adjusted to about 0.5 to 1.0 mm by changing the thickness of the bearing collar 20.

A gap of about 1 mm is provided between the coupling 4 connected to the parabolic head 1 in the drawing and the contact surface in the axial direction of the output shaft 5 directly connected to the drive source 6, and the back is made of kneaded and melted resin. The pressure does not apply a load to the speed reducer 6.

In the motor driven injection device, the drive of the motor is connected to the plunger via a timing belt or a ball screw. In the process of filling the mold with the resin, the plunger receives a reaction force from the resin.
The speed and pressure control targets are switched based on the torque detection current at this time. At this time, the switching timing and the control to the set value of the speed and pressure have been conventionally performed by a method generally referred to as classical control mainly using PID, but this time, a time response program for predicting a control target is used. Set. For this prediction, the dynamic characteristic of the controlled object is set internally as a transfer function. For this transfer function, a constant is determined in advance for each material forming condition. When a material or molding condition that does not match the constant appears, a region in which the reaction sensitivity and the like can be finely adjusted is set as a user parameter. The target value is always stored for some number of steps, and control is performed by considering the current target value as a future target value for some number of steps.

[0020]

In the kneading machine according to the present invention, the input port 10 on the upper part of the barrel 11 via the hopper 8 while rotating the parabolic head 1 (normally 50 rpm to 150 rpm).
When plastic pellets are charged as a material to be kneaded from above, the pellets are drawn into the spiral groove 3 of the parabolic head in a heated state, and are kneaded in a molten state along the spiral groove 3 in front of the parabolic head 1. The kneaded material is forcibly fed and can be discharged from the discharge port 9 of the barrel 11.

[0021]

EXAMPLE Using a kneader according to the present invention, an injection molding machine was manufactured as shown in FIG. In this injection molding machine, the resin kneaded and melted by the parabolic head is discharged from the discharge port 9 of the barrel 11 and passes through the flow path 21 of the manifold block A12 in which the temperature is maintained in accordance with the resin by the heater. This is a pre-plastic injection molding machine having a structure in which a space is filled between a pot 14 in a manifold block B13 whose temperature is maintained by a heater and a plunger 15 in standby for injection.

When injection molding was performed under the following conditions, six types of plastic materials were uniformly kneaded, and a molded product was obtained efficiently. Diameter of cone head: 80 mm Sectional shape of spiral groove: width 5 mm, depth (tip) 2 mm,
Depth (hem) 4 mm Number of spiral grooves: 1 Temperature of parabolic head: 200 to 400 ° C Temperature of barrel: 200 to 400 ° C Rotation speed of parabolic head: 50 rpm to 150 rpm Material of plastic pellet A: Acrylic nitrile butylene Styrene Plastic pellet material B: Polypropylene Plastic pellet material C: Polycarbonate Plastic pellet material D: Polyacetal Plastic pellet material E: Polybutylene terephthalate Plastic pellet material F: Polyphenylene sulfide

[0023]

According to the present invention, in an injection molding machine or the like, the kneading section realizes space saving, and since the kneading section is provided above the injection mechanism, the barrel and the screw can be easily removed. Yes, no time is required for maintenance. The molten resin can provide a viscosity distribution stepwise during kneading with a parabolic screw. This leads to not giving excessive stress to the resin itself during the melting process of the resin. Therefore, the internal stress of the molded product is reduced, and molding defects (warpage, sink, etc.) are reduced. In addition, since the thrust load due to the back pressure of the resin does not apply a load to the driving source, the structure of the plasticizing / injection device does not need to be complicated and high rigidity is required, so that the device cost is reduced. Further, since the shape of the bearing portion can be reduced in size, space saving can be realized.

Further, since the length of the parabolic head and the barrel is shorter than half the length of a commercially available single screw, no time is required for replacing the resin. Therefore, it can be used for molding processing of multi-product small-quantity production in which resin exchange and replacement are complicated. The resin material to be filled is pressurized and is a non-Newtonian fluid and a viscoelastic body in a solidified state. Therefore, the amount of movement of the plunger is not proportional to the compressive stress applied to the resin material filled in the mold. The control method devised this time can provide a resin material that is excellent in followability of operation. As a result, the internal stress of the product after molding is reduced, and molding defects (warpage, sink, etc.) are reduced.

Therefore, it can be said that the industrial applicability of the present invention is very high.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a kneading screw according to the present invention.

FIG. 2 is a sectional view of a main part of the injection molding machine according to the present invention.

FIG. 3 is a side view of a parabolic head.

FIG. 4 is a sectional side view of a main part of a kneading screw of a conventional injection molding machine.

FIG. 5 is a sectional side view of a main part of a kneading screw of a conventional extruder.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Parabolic head 2 Parabolic surface 3 Spiral groove 4 Coupling 5 Output shaft 6 Drive source 7 Motor 8 Hopper 9 Discharge port 10 Input port 11 Barrel 12 Manifold block A 13 Manifold block B 14 Pot 15 Plunger 16 Parabolic recess 17 Housing 18 Heat sink 19 Bearing 20 Bearing collar 21 Flow path 22 Melt transport section 23 Melting section 24 Transport section 25 Cylinder 26 Single screw 27 Cone screw 28 Drive shaft 29 Hopper 30 Input port 31 Support rod 32 Heater 33 Flange 34 Discharge port 35 Hollow motor 36 Bearing

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[Procedure amendment]

[Submission date] February 29, 2000 (200.2.2
9)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction contents]

[Document Name] Statement

[Title of the Invention] Plasticizing and injection equipment

[Claims]

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a plastic material
And a plasticizing / injection apparatus.

[0002]

2. Description of the Related Art There are many conventional kneading machines of an injection molding machine by various means. As a typical example, as shown in FIG. 4, a resin is compressed and deformed to transport the resin. The in-line type single-screw screw 25 divided into a melting section 22 for forming a molten circulation flow by frictional heat and transfer heat of the section 23 , the cylinder 24 and the resin, and a melt transporting section 21 for transporting the molten resin to a resin discharge port. Are commercially available.

[0003] In addition, a linear rod-shaped screw as described above
The plasticizer and injection unit are separated using a so-called
Ripler injection molding machine (JP-A-10-315282)
Is being planned. However, used in the pre-plastic injection molding machine
The straight rod shaped screw is a conical screw shown in FIG.
It requires a longer member than the
The pace was increasing.

Further, the linear rod-shaped screw is made of resin.
Has the property that viscosity changes with temperature,
The frictional force between the resin and cylinder in the
Slipped between the cylinder and screw
The molding stability is reduced as a result.
Was. Therefore, we have an injection cylinder inside the screw,
By changing the screw shape to a parabolic shape, the resin can be transported to the measuring section.
Transmission capacity (JP-A-8-294948),
Lipra injection molding machine with screw type conical
(Japanese Patent Laid-Open No. 9-109201) has been proposed.

[0005] The transfer capability of the resin material is defined as resin / cylinder.
The friction force between the surfaces and the friction force between the resin and screw groove surfaces
The frictional force between the resin material and the cylinder surface is
Acts as a force to pull the resin material in the transport direction, and
The frictional force on the clew surface acts as a force that hinders resin transport.
Good. In other words, the screw shape can be parabolic or conical
By doing so, the resin is pushed toward the tip of the screw shaft
A force component is generated in the cylinder, and the component force
Works on the surface to amplify the frictional force between the resin material and the cylinder surface.
Convey resin efficiently.

In addition, heat resistance of nylon or liquid crystal polymer, etc.
Resins with high heat resistance and flame retardancy have a wide range of molding temperature and decomposition temperature.
Always narrow and sensitive to changes in temperature
Screw does not move if adopting a Lipa type injection molding machine
It is plasticized and is not affected by external heat.
Therefore, a constant heat history is always given to the resin,
Tree with high stability of state and discharged from screw
It is known that the supply of grease to the measuring section is stable.
You.

[0007]

THE INVENTION Problems to be Solved] However, the
The plasticizing / injection mechanism of Japanese Patent Application Laid-Open No. 8-294948
Injection plan that moves forward and backward in the injection cylinder in the screw
The jar transfers the high-temperature heat of the molten resin to the rear of the screw
As a result, the temperature at the rear of the screw becomes
Near the resin inlet at the rear, melting starts when the resin is transported.
Is started, causing resin clogging (bridge).
The conical screw 26 shown in FIG.
Because of a certain temperature distribution due to the heat of 1,
A structure in which the transport section, the melting section, and the melt transport section are integrated
Has become. Therefore, in the hopper 28, the same resin as described above is used.
This will cause clogging.

Further, as described above, the resin melts simultaneously with the transportation.
When melting starts, the plastic material is metal, etc.
Has low thermal conductivity compared to other materials and heat penetrates into the resin.
It is difficult to mix with screw.
Heating the resin pellets without performing the process makes contact with the heated surface
Only melts. In this case, the thermal decomposition of the material is uneven.
Even if the whole melts, the resin material deteriorates and
The product with the mark may not be obtained.

Further, the conical screw 26 is
Too steep tip angle at the rear end of the clew that diameter
When resin melts, high back pressure is created here
I will. As a result, a high thrust force is applied to the bearing portion. This
Therefore, the size of the bearing section has been increased and the equipment cost has been increased.
Was.

[0010] The plasticizing / injecting apparatus according to the present invention has the above-mentioned problems.
The problem was solved, and the injection mechanism and kneading mechanism were separated.
Because it is a pre-plastic type, it is always constant in the kneading section
Since it is possible to give a thermal history to the resin,
In the process of applying the temperature for melting,
A stable temperature gradient up to
Such resin clogging is eliminated. In addition, in the conventional product
Use a screw instead of a straight rod or conical screw.
Parabolic head with parabolic cross-sectional shape that forms a spiral groove 2
By using the pad 1, the resin can be
It can be transported in the edge direction.

In addition, a cross section of the parabolic head 1
Is convex in the tip direction, and as shown in FIG.
Is represented as a vertex in a coordinate system, Y = nX ² (n = a ₁ ,
a ₂ , a ₃ ,...)
It is desirable to combine multiple parabolic
No. In particular, in FIG. 6, (a ₁ <a ₂ <a ₃ <...)
So that the outermost line is the outer circumference of the screw section
Set so that For example, the release of Y = a ₁ X ² in FIG.
The parabola in the region of FIG. 7 and the parabola of Y = a ₂ X ²
Area. If you take this method, near the screw tip
With stronger resin material and friction force on cylinder surface
The compression force is obtained and the diameter at the rear end of the screw increases.
No thrust force is applied to the bearing
Can be reduced.

[0012] Furthermore, a tree which is sensitive to a temperature change.
For fats, stir well before thermal decomposition and dissolve evenly.
In order to fuse, as shown in FIG.
Connects smoothly to the rear end of the parabolic head 1
It is desirable. If this is a conical screw,
When connecting the straight rod screw, the connecting point is the bending point
Which results in resin retention and seizure
Not appropriate.

[0013]

According to the present invention, there is provided an injection molding machine comprising:
One plasticizing / injection device is used from the center of the tip to the hem.
Is a rotatable parabolic screw formed with a plurality of spiral grooves 2.
In the view, the outline of the screw cross section is
Screw type parabolic head 1
Placed inside the barrel forming the inner space to match the shape
Plasticizer and parallel or angled plasticizer
Plasticization and mixing by the injection device
Plasticization and injection characterized by injection of kneaded resin
Discharge device, the plasticizing device has a discharge port at the tip of the barrel
8 and a parabolic recess of the barrel 10 on the side.
It has an inlet 9 communicating with the part 15 and has a parabolic cross-section
Between the parabolic head 1 and barrel 10
From the input port 9 while rotating at a minute interval
The molten resin is injected from the discharge port 8 by adding resin pellets.
It is characterized by discharging fat. Also
The injection device is a molten resin discharged by the plasticizing device.
Is waiting for injection with the pot 13 via the resin backflow prevention mechanism
Is filled between the plunger 14
You.

Further, the rear end of the parabolic head 1
Connect the straight rod screw smoothly as shown in Fig. 7.
And stir the resin sufficiently according to the desired resin material.
The material may be uniformly melted.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
A description will be given based on FIG. FIG. 1 shows a coupling 3 on the back.
A parabolic head having a parabolic shape having an output shaft 4 driven by a drive source 5 through a center of the parabolic head has a single spiral groove 2 formed from the center to the rear of the head as shown in FIG.

As a material of the parabolic head 1, a structural steel (SCM440H) having excellent seizure resistance and scoring characteristics by surface quenching and quenching is used.
In order to adjust the temperature of the parabolic head 1, a band heater is attached to the barrel 10, and the temperature can be adjusted according to the kneading conditions of the material to be kneaded.

The shape of the spiral groove 2 of the parabolic head 1
The shape, cross-sectional shape and number thereof are not particularly limited.
It is appropriately selected according to the properties of the material to be kneaded.
Also, the cross-sectional shape is desirably not linear but parabolic
Shape gives ideal viscosity distribution in kneading resin material
To be designed. In addition, the response to temperature changes is too sensitive
Resin such as nylon and liquid crystal polymer
In order to stir resin pellets sufficiently for thermal decomposition
It is necessary to provide an area, but the rear end of parabolic head 1
As shown in Fig. 7, smooth the straight rod screw
Can be combined.

In the figure, reference numeral 10 denotes a cylindrical barrel (hereinafter referred to as "barrel") having a parabolic concave portion 15 in the center of one side surface which coincides with the parabolic head 1 and a discharge port at its tip.
8 , and an input port 9 reaching the parabolic recess 15 at the upper part.

The material of the barrel 10 is a structural steel (SCM440) excellent in seizure resistance and galling characteristics by performing surface nitriding and quenching in the same manner as in the case of the parabolicer 1.
H) is used, and by making the barrel cylindrical, heat transfer from the band heater attached to the barrel 10 to the parabolic head 1 is made uniform.

Further, a heat sink 17 is provided at the inlet of the barrel 10 and the parabolic recess is formed by the hopper 7 under its own weight.
The resin reaching 15 does not cause bridging due to thermal melting.

FIG. 1 is an overall configuration diagram of a kneader according to the present invention.
The housing 16 and the manifold block A 11
The barrel 10 is fixed by, parabolic recess of the barrel 10
Para bola head 1 to 15 so as to coincide, and press-fitting the cylindrical portion of the para bola head back to bare <br/> ring 18. An output shaft 4 is connected to the center of the cylindrical portion via a coupling.

The spacing between the parabolic head 1 and the parabolic recess 15 of the barrel 10 is usually set to about 0.4 mm. This gap can be reduced to 0.5 mm by changing the thickness of the bearing collar 19. It can be adjusted to about 1.0 mm.

[0023]

In the kneading machine according to the present invention, when the parabolic head 1 is rotated (usually at 50 rpm to 150 rpm), resin pellets are charged as a material to be kneaded from the charging port 9 on the upper part of the barrel 10 via the hopper 7 . The pellets are drawn into the spiral groove 2 of the parabolic head 1 in a heated state, and are forcibly sent to the front of the parabolic head 1 along the spiral groove 2 while being kneaded in a molten state.
The kneaded material can be discharged from the 10 discharge ports 8 .

[0024]

EXAMPLE Using a kneader according to the present invention, an injection molding machine was manufactured as shown in FIG. The injection molding machine, resin is kneaded melted by para bola head 1, is discharged from the discharge port 8 of the barrel 10, passes through the flow channel 20 of the manifold block A 11 temperature depending on the resin is kept in a heater Similarly, the pot 13 in the manifold block B 12 whose temperature is maintained by the heater and the plunger in the injection standby state
14 is a pre-plastic structure.

When injection molding was performed under the following conditions, six types of plastic materials were uniformly kneaded, and a molded product was obtained efficiently. Diameter of cone head: 80 mm Sectional shape of spiral groove: width 5 mm, depth (tip) 2 mm,
Depth (hem) 4 mm Number of spiral grooves: 1 Temperature of parabolic head: 200 to 400 ° C Temperature of barrel: 200 to 400 ° C Rotation speed of parabolic head: 50 rpm to 150 rpm Material of plastic pellet A: Acrylonitrile
Material of lenstyrene plastic pellet B: Polypropylene Material of plastic pellet C: Polycarbonate Material of plastic pellet D: Polyacetal Material of plastic pellet E: Polybutylene terephthalate Material of plastic pellet F: Polyphenylene sulfide

[0026]

The kneading screw of the injection molding machine of the present invention
The cone has a direct taper from the rear end to the front end.
In contrast, the parabolic type has a screw cross-sectional shape
A combination of multiple parabolas that differ stepwise from the horizon
The change in curvature near the screw tip
Because of its large size, the resin is rapidly compressed near the tip and efficiently
Changes to a flowing state. In this way, the molten part of the resin
Because it is concentrated at the tip of the screw,
There is no need to set a high degree and resin clogging does not occur
Become. In addition, plasticization and measurement of resin due to pre-plasticization
And the repetition of molding is stable.

The use of the kneading screw
Makes the outline of that section a single parabolic shape
Screw length can be shortened compared to
At the rear end of parabolic head 1
Because it is possible to join, resin stagnation at the joint
No cling or seizure occurs. As a result, the molten resin
Stepwise viscosity distribution during kneading with parabolic screw
Can be given. This is the process of melting the resin.
Is to prevent excessive stress on the resin itself
You. Therefore, the internal stress of the product after molding is reduced.
Molding defects such as warpage and sink are reduced.

Further, since the kneading unit realizes space saving and the kneading unit is installed above the injection mechanism, the barrel and the screw can be easily removed, and no time is required for maintenance. In addition, since the length of the parabolic head or barrel is shorter than that of a commercially available single-screw screw, which is less than half, no time is required for replacing the resin. Therefore, this injection molding can be used for molding of various kinds and small-quantity production.

Therefore, it can be said that the industrial applicability of the present invention is very high.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a kneader according to the present invention.

FIG. 2 is a sectional view of a main part of the injection molding machine according to the present invention.

FIG. 3 is a side view of a parabolic head.

FIG. 4 is a sectional side view of a main part of a kneading screw of a conventional injection molding machine.

FIG. 5 is a sectional side view of a main part of a kneading screw of a conventional extruder.

FIG. 6 illustrates an outline of a cross section of a screw according to the present invention.
Figure

Fig. 7 Straight bar screw on parabolic head
Side when combined Figure

[Description of Signs] 1 Parabolic head 2 Spiral groove 3 Coupling 4 Output shaft 5 Drive source 6 Motor 7 Hopper 8 Discharge port 9 Input port 10 Barrel 11 Manifold block A 12 Manifold block B 13 Pot 14 Plunger 15 Parabolic recess 16 Housing 17 Heat sink 18 Bearing 19 Bearing collar 20 Flow path 21 Melt transport section 22 Melting section 23 Transport section 24 Cylinder 25 Single screw 26 Conical screw 27 Drive shaft 28 Hopper 29 Input port 30 Support rod 31 Heater 32 Flange 33 Straight line Rod screw

[Procedure amendment 2]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG.

FIG. 2

FIG. 3

FIG. 4

FIG. 5

FIG. 6

FIG. 7

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kensuke Shiraki 811-1 Kanda, Nogata-shi, Fukuoka F-term (reference) 4F206 JA07 JD04 JF13 JF21 JM01 JN03 JQ42 4F207 KA01 KA07 KF13 KK12 KK26 KL05 KL28

Claims (6)

[Claims] An output shaft (5) rotated by a drive source (6) and a parabolic surface (2) directly connected to a coupling (4) having one or more spiral grooves (3) formed from the center to the bottom of the parabola (2). On the parabolic or tapered tip,
A parabolic head 1 having a combination or any one of a taper, a paraboloid, and a spherical surface having different angles, and a parabolic concave portion 16 that matches the parabolic surface 2 of the parabolic head 1 is formed at the center of the barrel 11. And the parabolic recess 16
Is provided with a discharge port 9 at the tip thereof, and an input port 10 communicating with a parabolic concave portion 16 of a barrel on the side surface. 1. A plasticizing / injection device having a kneading screw of a kneader kneaded and melted by a paraboloid 2 near the tip of 1. 2. A kneading screw according to claim 1, wherein a thrust load caused by a back pressure of the resin melt-compressed at the tip of the parabolic head does not apply a load to the drive source. Plasticizing and injection equipment with a structure. 3. The plasticizing / injecting apparatus according to claim 1, further comprising a structure for performing measurement and injection at a part different from said part. 4. The plasticizing / injection apparatus according to claim 3, wherein the plasticizing / kneading apparatus and the injection apparatus are arranged in parallel or at an angle. 5. The plasticizing / injecting apparatus according to claim 3, wherein a plastic backflow preventing mechanism using a sphere is disposed in the middle of the flow path of the plasticizing / kneading apparatus and the injection apparatus. apparatus. 6. The plasticizing / injection apparatus according to claim 3, wherein the driving force of the motor is transmitted to the ball screw, and the control target of the speed and the pressure is controlled based on the torque detection current of the motor. Switch. At this time, a plasticizing / injection apparatus having a structure in which a time correspondence program for predicting a control object is set for controlling the switching timing and the control to the set values of speed and pressure, and the torque detection voltage of the ball screw is used as a reference for starting.