JPH0475125B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to improvements in methods for controlling temperature and pressure in resin processing equipment, particularly in injection and extrusion equipment.

[Conventional technology]

In general, there are various methods for molding plastics depending on the properties of the resin and auxiliary materials, but most of them utilize the heat-resistant properties of the resin, that is, thermoplasticity or thermosetting. is occupying.

Such molding methods include compression molding, transfer molding, injection molding, extrusion molding, blow molding, calendering, etc. Among these,
A thermoplastic molding material is supplied into the cylinder from a supply device, sent to a heating section by a screw or a plunger, and the molding material, which is heated and pressurized in the heating section and becomes plastic, is provided at the tip of the cylinder. Apparatus for shaping by extrusion through a nozzle or die, or even for shaping the extrudate in a press mold, are known and widely used for shaping thermoplastic or thermosetting materials. .

In the above-mentioned molding equipment, it is necessary to heat and compress the molding material to a predetermined temperature and pressure determined mainly by the type of synthetic resin that is the raw material of the molding material, and to fluidize it. If this is not maintained, the filling of the mold may be incomplete, or the product may have pores, cracks, distortion, etc., resulting in incomplete processing.

However, the desired temperature of the resin extruded into the nozzle or die varies depending on the shape of the product, the temperature of the mold, the pressure inside the cylinder, the extrusion cycle, the amount of extrusion per product, etc. is generally intermittent, whereas heating is continuous. In addition, the molding material is heated not only by the heaters installed in each part, but also by the shear heat generated as the screw rotates, so the temperature of the molding material fluctuates due to changes in the driving energy applied to the screw. However, this driving energy depends on the pressure and temperature of the resin inside the cylinder.

In addition, in the conventional device, a heating wire is provided inside the cylinder or along the outer peripheral surface, and the cylinder is heated by heat conduction from the heating wire, thereby heating the molding material. The heat capacity of the heating wire is large, and the heat capacity of the heating wire itself and the coating material of the heating wire are related to temperature control, so it is difficult to accurately raise or lower the temperature of the cylinder to the desired value, and furthermore, the temperature inside the cylinder Since the resin moves intermittently, there is a problem in that it is difficult to keep the molding material extruded from the cylinder at a constant temperature suitable for processing.

[Problems to be solved by the present invention]

The present invention has been made based on the above-mentioned viewpoints, and its purpose is to configure a molding material to be heated more rationally, and thereby appropriately adjust the temperature and pressure of the molding material. The objective is to always maintain the resin extruded from the equipment at the optimum temperature and pressure for processing, reduce pores, cracks, distortion, etc. of the product, improve molding accuracy, and shorten molding time.

[Means for solving problems]

The above object is to provide a resin processing apparatus for molding a thermoplastic or thermosetting molding material by providing a large number of temperature detectors and pressure detectors in a cylinder and a mold for molding. In addition to detecting the temperature and pressure of the molding material in each part of the mold, the temperature and pressure of each part of the device is determined based on the detected values of the multiple temperature detectors and pressure detectors and the amount of movement of the material. Predicting changes over time, comparing the predicted values with predetermined reference temperature distribution and pressure distribution, and heating the driving speed of the screw or plunger and the molding material in the cylinder so that the two match. This is achieved by controlling the amount of heat generated by the vessel.

The temperature and pressure distribution inside the cylinder are mainly compared with predetermined ideal temperature and pressure distributions, and the amount of energy input is determined in whole or in part based on the deviation and the amount of resin movement. , and is controlled most rationally in response to deviations that are expected to occur over time.

[Effect]

With the above configuration, the energy given to the resin in each part of the cylinder is optimally controlled over time and space depending on the speed of movement of the resin, and the temperature and pressure of the resin extruded from the cylinder are always optimal for processing. maintained in good condition.

〔Example〕

Hereinafter, the details of the present invention will be specifically explained with reference to the drawings.

FIG. 1 is an explanatory diagram showing an embodiment of the apparatus for carrying out the method of controlling temperature and pressure in a resin processing apparatus according to the present invention, and FIG. 2 is an enlarged sectional view of the cylinder portion thereof. FIG. 3 is an explanatory diagram showing another embodiment.

In Figure 1, 1 is a cylinder, 2 is a screw, 3 is a cylinder.
is a flange for mounting the cylinder, 4 is a column in which a reduction gear is housed, 5 is a motor, 6 is a material replenisher, 7 is a replenisher intermediary member, 8 is a column that supports the tip of the cylinder 1, 9, 10 is a mold for molding, 1
1 is a mold mounting member, 12 is a breaker plate, 1
3 is a wire mesh, 14-1 to 14-5 are inductors (excitation coils for high-frequency induction heating), 15-1 to 15-
14 is a temperature detector, 16-1 to 16-14 are pressure detectors, and 17 is the temperature detector 15-1 to 1.
5-14 is an AD converter that converts the output into a digital signal, 18 is an AD converter that converts the output of the pressure detectors 16-1 to 16-14 into a digital signal, and 19 is a power source for the inductors 14-1 to 14-5. 20 is a hydraulic cylinder that applies pressure to the molds 9 and 10 for molding; 21 is a hydraulic switching valve that switches the flow of oil to the hydraulic cylinder 20; 22 is a hydraulic pump; 23
24 is an oil tank, 24 is a power supply device for the motor 5, and 25 is a control device.

In Figure 2, the same numbers as those in Figure 1 indicate the same components, and 26
29 to 29 are lock nuts, and 30 is a heat insulating material.

A part of the cylinder 1 is supported via a flange 3 by a column 4 in which a reduction gear is housed, and its tip is supported by a column 8, and a mold attachment member 11 is attached to the tip. attached.

The screw 2 is rotatably provided coaxially within the cylinder 1 and is connected to the output shaft of a speed reducer housed in a column 4 that decelerates the rotation of the motor 5 and increases the torque. The molding material supplied from the replenisher 6 into the cylinder 1 is sent to the heating section, and at the same time the molding material is pressurized and heated by the cutting heat accompanying the rotation, and is further heated in the heating section to become plastic. The molding material is extruded into molds 9 and 10 for molding.

The output of the power supply device 24 that supplies electric power to the motor 5 is controlled by a control device 25, which controls starting and stopping of the motor 5 and its rotation speed.

A breaker plate 12 having a large number of holes and a wire mesh 13 held by the breaker plate 12 are provided between the tip of the cylinder 1 and the mold attachment member 11. This makes the flow of the molding material uniform and improves the quality of the material. The mixture is kneaded to uniformize heating, and at the same time, pressure is applied inside the cylinder 1.

Further, a hydraulic cylinder 20 is connected to the molds 9 and 10 for molding, which are connected to the cylinder 1 via the mold mounting member 11, and oil from a hydraulic pump 22 is switched by a hydraulic switching valve 21. As a result, a desired pressure is applied to the molds 9 and 10 for molding. Further, the replenisher 6 is attached to a replenisher mounting member 7 fixed to the flange 3 for attaching the cylinder 1, and supplies molding material into the cylinder 1.

A plurality of inductors 14-1 to 14-5 are provided at appropriate intervals along the outer periphery of the cylinder 1, and AC power is supplied from the power supply device 19 to heat the cylinder 1 by induction heating.

In addition, a plurality of temperature detectors 15-1 to 15-11 and pressure detectors 16-1 to 16-11 are attached to the cylinder 1 at appropriate intervals, and at each position in the cylinder 1. The temperature and pressure of the molding material are constantly detected.

Although the outer peripheral wall surface of the cylinder 1 is omitted in FIG. 1, it is usually covered with a heat insulating material 30 as shown in FIG. It is configured to be heated.

Further, the temperature detectors 15-1 to 15-11 and the pressure detectors 16-1 to 16-11 are screwed into the cylinder 1 via the heat insulating material 30 and fixed by lock nuts 26, 27, 28 and 29, respectively. has been done.

Therefore, the temperature detectors 15-1 to 15-1
1 and pressure detectors 16-1 to 16-11, the temperature and pressure of the molding material can be accurately detected.

In general, the above-mentioned dielectric heating involves winding a coil called an inductor around a cylindrical conductor, and when alternating current is passed through the inductor, eddy current is generated in the conductor due to electromagnetic induction, and the conductor is heated by the eddy current generated at this time. Generates heat due to current loss. In this case, since the alternating current has a skin effect, the eddy current concentrates on the surface of the conductor and decreases exponentially toward the center. The depth of penetration of this eddy current is inversely proportional to the square of the frequency of the alternating current supplied to the inductor, so by setting this frequency appropriately, the depth of penetration can be freely changed. can be heated efficiently.

Therefore, the inductors 14-1 to 14 of cylinder 1
The portion provided at -5 constitutes a heating section, and the molding material is heated in this heating section by heat conduction from the inner circumferential surface of the cylinder 1. In this case, the dielectric 14-
Increase the power supplied to 1, and then sequentially 14-2,
The power is reduced in the order of 14-3, 14-4, and 14-5 so that the temperature rise in the cylinder 1 becomes gradually gradual from the material supply port to the outlet side, and The desired temperature is maintained at the first resin extrusion port.

The mold attachment member 11 is attached to the tip of the cylinder 1 and has a funnel-shaped flow path that guides the material extruded from the cylinder 1 to the molds 9 and 10 for molding. It is attached to member 11, from which fluidized molding material is extruded and molded into a desired shape.

When molding is performed by the molding apparatus according to the present invention, when granular or powder molding material is supplied into the cylinder 1 from the replenisher 6, the motor 5 drives the molding material. The screw 2 rotates, and the molding material is delivered to the heating section of the cylinder 1. At the same time, alternating current is supplied from the power supply 19 to the inductors 14-1 to 14-5 provided in the heating section of the cylinder 1. 1 generates an eddy current, which generates heat by induction heating.

The heat generated by induction heating has two to three times better power efficiency than heating using electric heating wires, etc., is inexpensive and has excellent durability, and is not heated by applying heat to the cylinder 1 from the outside. Since the heating means directly generates heat to heat itself, the heat capacity of the heating means is less likely to be involved in temperature control, so the temperature can be adjusted in immediate response to commands from the control device 25.

A plurality of temperature detectors 14-1 to 14-14 provided in the cylinder 1 and the molds 9 and 10 for molding, respectively.
and the temperature at the position of each detector of the molding material supplied from the cylinder 1 into the molds 9, 10 and moved within the cylinder 1 by the pressure gauge detectors 15-1 to 15-14. and pressure are detected, and these detected values are converted into digital signals by A/D converters 17 and 18, respectively, and sent to the control device 25.

This will be explained more specifically.

First, regarding temperature, the control device 25
First, the total calorific value of all the heaters is controlled according to the amount of resin extruded, and the total calorific value of the resin in the cylinder 1 is calculated, and this is calculated as a predetermined ideal temperature distribution. When comparing the total amount of heat that the resin should hold, if a deviation is found between the two, each inductor 14-1 to 14- 5
Adjust the amount of power supplied to. For example, if the temperature detected by the temperature detector 15-2 is lower than a predetermined temperature, first, the amount of power supplied to the inductor 14-2 is increased, and the resin in the cylinder 1 is After the time required to move from the inductor 2 to the inductor 14-3 has elapsed, the heating power for the inductor 14-3 is increased. Therefore, the molding material passes through the inductor 14-3 of the cylinder 1 and is heated to near a predetermined temperature, and the subsequent molding material passes through the inductors 14-2 and 14-3. This results in heating to a predetermined temperature.

Therefore, further downstream temperature detectors 15-3 to 15-1
When excess or insufficient heating is detected in step 5-14, the amount of heating is changed over time as described above.

Therefore, the power supply amount of all the inductors 14-1 to 14-5 is not uniformly increased, but the power supply amount of only one specific inductor, for example, 14-1 is increased. Instead, as the molding material whose temperature is lower than a predetermined temperature moves inside the cylinder 1,
Since the amount of energy supplied to the heater corresponding to that part and the heater in the preceding stage is adjusted, the material is sequentially transferred to the inductors 14-1 to 14-5 according to its movement.
properly heated. Therefore, the molds 9, 1 for molding
While moving toward the zero direction, the temperature of the molding material is controlled to a predetermined temperature state without rising too much.

Next, regarding pressure, since the temperature is controlled as described above, the melting degree and viscosity of the resin can be ideally controlled, and the driving speed of the screw 2 can be appropriately controlled according to the extrusion speed of the resin. For example, the pressure distribution immediately becomes an ideal distribution.

Therefore, the molding material is heated and pressurized by the heat conduction from the inner wall surface of the cylinder 1, the rotation of the screw 2, and the accompanying shear heat, and is maintained at a temperature and pressure suitable for injection, and becomes a fluid. , mold mounting member 11
As the product is extruded at a constant speed into the molds 9 and 10 through the molds 9 and 10 and molded into the desired shape, it is possible to reduce pores, cracks, distortion, etc. of the product, and improve molding accuracy. You get a significant reduction in molding time.

FIG. 3 shows an injection molding apparatus, and in FIG. 3, the same numbers as those in FIGS. 1 and 2 indicate the same components, and 31 32 is a motor housing, 33 is a motor, 34 is a piston, 35 is a rod, and 36 is a hydraulic cylinder.

The screw 2 is rotatably provided within the cylinder 1 and slidably in the axial direction, and is rotated by the drive of the motor 33 to feed out the molding material supplied from the replenisher 6. At the same time, the molding material is heated by the shear heat generated at that time, moves as the piston 34 moves, is heated and pressurized in the heating section, and is molded into a plastic form from the nozzle part of the mold attachment member 11. This is for injection into molds 9 and 10 for use.

A check valve 3 is provided at the tip of the screw 2 to prevent the material from flowing back when injecting the molding material from the nozzle part of the mold attachment member 11 into the molds 9 and 10.
1 is provided.

The motor 33 is housed in the motor housing 32 and is attached to one end of a rod 35 connected to the piston 34, and moves in the axial direction in conjunction with the piston 34. Its drive shaft is connected to the screw 2 and rotates the screw. 2, the piston 34 slides within a hydraulic cylinder 36 connected to the motor housing 32 and moves the motor 33 in the axial direction via the rod 35.

At the beginning of each cycle, the screw 2 is in the retracted position within the cylinder 1 (the position shown in the figure), and when granular or powdered molding material is supplied from the supply device 6 into the cylinder 1, the motor 33 The screw 2 is rotated by the drive of the cylinder 1, and the molding material is sent out toward the heating part of the cylinder 1, and the inductor 14 provided in the heating part of the cylinder 1
-1 to 14-5 are supplied with alternating current from a power supply 19 to generate an eddy current in the cylinder 1, which generates heat by induction heating.

The molding material is heated and pressurized by the heat conduction from the inner wall surface of the cylinder 1, the rotation of the screw 2, and the accompanying shear heat, and is given a temperature and pressure suitable for injection, and becomes a fluid. The screw 2 is then sent to the space formed by the tip of the cylinder 1 and the inner wall of the mold attachment member 11, and then the screw 2 is inserted into the piston 34.
The molding material sent to the cavity is injected into the molds 9 and 10 from the nozzle part of the mold mounting member 11 to form the desired shape. molded into a shape.

In addition, during processing, temperature detectors 15-1 to 15-
14 and converted into a digital signal by the AD converter 17, the control device 25 calculates the total amount of heat held by the resin in the cylinder 1,
This is compared with the total amount of heat that the resin should hold in a predetermined ideal temperature distribution, and if a deviation is found between the two, each inductor 14-1 to Control similar to that of the apparatus shown in FIG. 1 is performed by adjusting the amount of power supplied to 14-5.

Similarly, the pressure is also measured by the temperature detectors 16-1 to 16-1.
Based on the detection value detected by 6-14, the control device 25 controls the driving speed of the screw 2 and the moving speed of the piston 34, so that the melting degree and viscosity of the resin are ideally controlled. The distribution is always kept in an ideal state, and when it deviates from this state, control is immediately performed to make the pressure distribution ideal.

〔Effect of the invention〕

Since the present invention is constructed as described above, the energy given to the resin in each part of the cylinder is optimally controlled over time and space, so the temperature and pressure of the resin extruded from the cylinder are controlled. It is always maintained in the optimum condition for processing, and therefore it is possible to reduce pores, cracks, distortion, etc. of the product, improve molding accuracy, and significantly shorten molding time.

Note that the configuration of the present invention is not limited to the above-mentioned embodiments. That is, for example, in the embodiment, an inductor with a non-ferrous core is provided around the cylinder, but an inductor with a non-ferrous core in which a coil is wound around an iron core may also be used. In this case, a plurality of iron core inductors are provided around the cylinder to form a set, and a plurality of sets are provided at appropriate intervals. In addition, each inductor 14-
It is also recommended that a pipe through which the coolant flows through cylinder 1 be wound around the cylinder 1 between sections 1 to 14-5, and a device that can control the temperature while stopping or adjusting the flow rate of the coolant in each pipe is also recommended. Ru. In addition, the mounting position of the temperature sensor and pressure sensor, the method of controlling each part, etc. can be freely changed within the scope of the purpose of the present invention, and the present invention encompasses all of them. .

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an embodiment of the apparatus for carrying out the method of controlling temperature and pressure in a resin processing apparatus according to the present invention, and FIG. 2 is an enlarged sectional view of the cylinder portion thereof. FIG. 3 is an explanatory diagram showing another embodiment. 1...Cylinder, 2...Screw, 3...Flange, 4...Reduction gear, 5, 33...Motor,
6... Supply device, 7... Supply device mounting member, 9, 10
... mold for molding, 12 ... breaker plate,
13... wire mesh, 14-1 to 14-5... inductor,
15-1 to 15-14...Temperature detector, 16-1
~16-14...Pressure detector, 17,18...
AD converter, 19, 24...Power supply device, 20, 3
6...Hydraulic cylinder, 21...Hydraulic switching valve, 22
... Hydraulic pump, 23 ... Oil tank, 25 ... Control device, 26, 27, 28, 29 ... Lock nut, 30 ... Insulating material, 31 ... Backflow prevention valve, 32
...Motor housing, 34...Piston.

[Claims]

1 A rotary drive roll having a cylindrical body circumferential surface is separated from a valley-shaped recess that narrows at the end between a pair of side walls in contact with the body circumferential surface at intervals in the axial direction of the roll. combined with a housing having a rubber reservoir compartment formed by a stationary concave arc-shaped surface facing the rotary drive roll and open to the atmosphere between the concave arc-shaped surface and the rotary drive roll; A rotary roll type extruder is used in which a removable and replaceable mouthpiece is fixed to a housing to form a predetermined extrusion molding gap with a rotary drive roll at the end of the compartment and on the exit side. A kneaded mixture of rubber or rubber-like material corresponding to the amount of rubber or rubber-like material to be extruded through the mouthpiece is placed in the compartment under the action of atmospheric pressure on the inlet side opposite to the mouthpiece of the rotating drive roll. The height (H) of the above-mentioned kneaded material, which occupies the rubber reservoir compartment while being supplied in the form of a band along the circumference of the cylindrical body, measured from the level of the mouthpiece is adjusted to the common logarithm of the molding gap gauge (mm) of the mouthpiece. On the rectangular coordinates of X and the common logarithm y of the mouthpiece pressure gradient (Kgf/cm ² ) corresponding to the gauge, the following formula (1),
(2)