JPH0486240A - Resin molding apparatus - Google Patents

Abstract

PURPOSE:To grasp and control always correctly the state of resin under molding and conducting the high quality molding of constant quality resin by performing the control of resin pressure, resin temperature, and atmospheric temperature so as to be made constant at all times. CONSTITUTION:A resin pressure sensor 49 detects the pressure of molten resin 26 at any time and, in the case of being different from the previously limited standard pressure, serves to change the speed of a motor 36 in order that it becomes equal to the standard pressure. A resin temperature sensor 50 detects the temperature of the molten resin 26 at any time and, in the case of being different from the previously set standard temperature, acts to conduct the on-off control of a heater 31 in order that it becomes equal to the standard temperature. Next, an atmospheric sensor 54 detects the atmospheric temperature of a space at any time wherein resin 26 discharged from a discharging port 40 exists and, in the case of being different from the previously set standard temperature, performs to change the speed of a blower 45. Besides, a calculating device inputs the detected signals from each sensor, and carries out the control of pressure, temperature, and the like.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a resin molding device, and particularly to a device for forming a film or the like in a predetermined shape by discharging molten resin supplied by an extruder from a discharge port of a die. The present invention relates to a resin molding machine that can be automatically controlled to maintain constant molding conditions.

[Conventional technology]

Generally, thermoplastic resin, etc. introduced from a hopper by an extruder is melted in a sealed cylinder while being transported by a screw conveyor, and then the molten resin is extruded toward a die having a predetermined shape. The molten resin is discharged from the discharge port of the die to create a desired film or the like.

FIG. 2 shows such a conventional resin forming apparatus, in which a hopper 2 is attached to the top surface of an extruder 1 for supplying a predetermined resin into a cylinder within the extruder 1. Inside the extruder 1, there is a screw conveyor 4 that transports the resin supplied from the hopper 2 toward the extrusion port of the head 3, and a screw conveyor 4 that transports the resin supplied from the hopper 2 toward the extrusion port of the head 3. A heater (not shown) is built in to melt the resin.

Further, a feeding pipe 5 curved upward is connected to the extrusion port of the head 3 of the extruder 1, and the tip of the feeding pipe 5 has a pipe for forming a tubular film, for example. The inlet portion 7 of the die 6 is detachably connected. An annular discharge port 9 for discharging the molten resin 8 in a thin cylindrical shape is formed on the upper surface of the die 6, and approximately at the center inside the discharge port 9 of the die 6. An air ejection port 11 is formed which blows air sent from an air supply port 10 formed below to blow and expand the resin 8 ejected from the ejection port 9. Further, an annular cooling air supply device 12 located outside the discharge port 9 of the die 6 is disposed near the top of the die 6, and supplies cooling air sent from a blower (not shown). The resin 8 discharged from the discharge port 9 in a cylindrical shape is sprayed to cool the resin 8.

Further, above the cooling air supply device @12, there are a plurality of kites [l-shira 1313,
... are disposed above the guide rollers 13, and a pinch roller 14 for conveying the planar resin 8 in a bowed manner is disposed above the guide roller 13.

A winding roller 15 for winding up the resin 8 is disposed downstream of the pinch roller.

In such a resin molding device, the resin 8 discharged from the discharge port 9 of the die 6 is supplied to the cooling air supply device 1.
2, a line 16 is formed to the floss 1 at the position where the resin 8 reaches its maximum diameter. and,
With this floss 1 to line 16 as the boundary, the resin temperature on the lower side is 100 to 120 degrees Celsius, while the thirst of the resin 8 on the lower side is 5 to 15 degrees Celsius lower than the temperature on the lower side. The maximum diameter and film thickness of the resin 8 change depending on the position of this floss [~ line. Therefore, the quality of the molded resin also changes according to this change.

However, in order to mold resin of constant quality, it is necessary to keep the molding conditions constant at all times, and especially in the case of equipment that automatically molds resin, it is necessary to keep the molding conditions constant. It is necessary to automatically detect this and control it to keep it constant. Therefore, several conventional control devices have been proposed for performing such control, such as those shown below.

First, the control device shown in FIG. 3 is based on the fact that the position of the line 16 to the floss 1 changes in the vertical direction when the molding conditions change. Detected using a photodetector, floss 1 to line 1
If the position of Floss 1 to Line 1G is different from the predetermined position, by controlling the air jet amount of the cooling air supply device 12 and moving Floss 1 to Line 16 in the vertical direction, Floss 1 to Line 1G is always kept at a constant position. The molding conditions are kept constant in this way.

In this control device, an infrared emitter 18 as a frost line detection device is arranged at a position corresponding to the formation position of the line 16 to the 70th line.
The infrared light emitter 1 is disposed on the opposite side of the resin 8 in the diametrical direction.
An infrared receiver 19 is provided which transmits the LC infrared light emitted from the resin 8 and receives the LC infrared light. This infrared receiver 1
9 is connected to an arithmetic device 20 that integrates the amount of infrared light received by the infrared receiver 19 and calculates the amount of light transmitted near the formation position A' of the frost line 16 of the resin 8. 20, the position of the frost line 16 of the resin 8 is determined based on the amount of light transmission from the calculation device 20, and cooling air is supplied to the cooling air supply device 12 according to the position of the frost line 16. Supply blower 1
A control device 21 that controls the rotation speed of the engine 7 is connected.

Then, by changing the number of rotations of the blower 17 according to the detected position of the line 16 to the floss 1, the amount of cooling air ejected from the cooling air supply device 12 is changed to adjust the position of the floss 1 to line 16. It holds it in place and covers it.

Next, the control device shown in FIG. 4 uses a frost line detection device or the like to arrange both the light emitter 22 and the light receiver 23 on one side of the resin 8 and detect changes in the amount of light reflected from the resin 8. It is the same as that shown in Fig. 2 except that the position of the norost line 16 is detected, and the position of the floss 1 to line 16 is detected and controlled by using the reflected light from the resin 8 instead of the transmitted light. It is something to do.

Next, the control device shown in FIG. 5 detects the positions of the floss 1 to line 16 by detecting the surface temperature at each position of the resin 8 using a plurality of hot water temperature detectors, and keeps the positions constant. The region between the resin discharge port of the die 6 and the 70-stripe line 16 is horizontally divided into a plurality of regions, for example, four regions T1. T2. T3. T'4 minutes ()
, a temperature sensor 2 is installed at a position corresponding to each of these areas.
41.21-2.2/4-3.2/14 are arranged and the surface temperature of the resin in each area is measured. If the molding conditions do not change, the resin temperature in each region will always be constant, so set the temperature value in each region to a predetermined value in advance, and if there is a change in the measured temperature, the frost line will be detected. 16 has changed, and supplies air to the cooling air supply device 12 to keep the position constant.
Show me? 1''), etc.

Next, the control device shown in FIG.
The resin 8 discharged from the discharge port of the die 6 is not located at the position of
The shape itself is observed and control is performed to maintain the shape in a predetermined shape. In other words, the shape of the resin when molding is carried out under normal conditions (shown by the broken line)
is stored as image data in a computer (not shown) in advance, and on the other hand, the shape 8 of the resin is actually photographed by the TV camera 25 during molding, and this stored image data is combined with the resin actually photographed. By comparing the shape with the shape of No. 8, a deviation in the shape is detected, and a blower (not shown) or the like is controlled to eliminate this deviation.

[Problem to be solved by the invention]

However, each of the above-mentioned control devices has drawbacks as described below, and is therefore insufficient as a control device.

First, in the case of a control device that detects the position of the frost line using a photodetector as shown in FIGS. 3 and 4, light is used as the detection means, so depending on the type of resin used, There are some resins in which the light transmittance or reflectance hardly changes between the upper side and the lower side of the line, and when such resins are used, there is a problem that the position of the frost line itself cannot be detected. Moreover, since the resin 8 being molded is constantly blown with cooling air from the cooling air supply device 12, the resin 8 itself constantly vibrates and moves during molding. Therefore, floss 1 to line 16 are not actually flat, but have an undulating sawtooth shape, so if you try to improve measurement accuracy,
The photodetector outputs a detection signal as if the frost fin 16 were always moving in the vertical direction. As a result, control signals are generated extremely frequently, and devices such as blowers that are actually driven for control cannot follow them, and as a result, highly accurate control cannot be performed.

Next, even if the position of the frost line is detected by measuring the surface temperature of the resin as shown in Fig. 5,
After all, the temperature distribution state in each region during molding differs depending on the type of resin used, so the temperature distribution varies depending on the resin. In addition to complicating the work as it is necessary to redo the settings, it is also necessary to increase the number of divided regions and the number of temperature detectors in order to improve measurement accuracy, which makes the device itself difficult. In addition to being expensive, its control is also complicated. Furthermore, since the vibration of the resin described above causes the cooling air to slightly differ depending on the location, there is a problem that the temperature detector is likely to make false detections, resulting in a lack of reliability as a control device.

Next, in the case of a device that performs control by capturing the shape of the resin during molding, as shown in Figure 6, the data used is the image itself, so the amount of data becomes enormous, and as a result, this data must be processed. This requires expensive equipment.

Furthermore, as described above, it is difficult to obtain a positive m shape due to vibrations of the resin, making it difficult to control molding conditions with high precision.

In this way, each of the above-mentioned control devices controls the
Observe the floss 1 to line of resin 8 or the shape of resin 8 itself, which has many unstable factors such as constant vibration and unpredictable local movements, and based on this. Since the molding conditions are controlled, there is a limit to the accuracy of the control, and there is a problem that it is difficult to control high viscosity and mold high quality resin with a good yield. Ta.

The present invention was made in view of the above-mentioned problems, and provides a resin molding device that can always maintain constant molding conditions and automatically mold resin of constant quality with a high yield. The purpose is to provide

[Means to solve or overcome the problem]

In order to achieve the above object, the resin molding apparatus according to the present invention includes a heater for melting the resin and a resin conveying means for conveying the molten resin at a predetermined pressure. A resin formed by connecting a die with a discharge port for molding and discharging the resin into a predetermined shape, and disposing a cooling air supply device near the discharge port of the die to cool the resin discharged from the discharge port. The molding apparatus includes a pressure detection means for detecting the pressure of the molten resin, a resin temperature detection means for detecting the temperature of the molten resin, and an atmospheric temperature of a space into which the molten resin is discharged. A detection means is provided for detecting the ambient temperature, and a control means for generating a control signal based on the value detected by each of these detection means, and the heater is controlled based on the control signal from the control means. and one of the resin conveying means and the air supply device is controlled.

[For production]

J: According to the present invention, the resin melted in the extruder is sent from the extrusion port to the die, the molten resin is molded into a desired shape by the die and discharged from the discharge port, and then the resin is cooled by the cooling air supply device. It is something to avoid. Then, the pressure, temperature, and ambient temperature of the molten resin are detected by the resin pressure horn detection means, the resin temperature detection means, and the atmosphere temperature detection means in the space where the resin is discharged, and the resin is controlled based on the detected values. Molding conditions can be kept constant by controlling the driving of a heater for melting, a resin conveying means for conveying the resin at a predetermined pressure, and a cooling air supply device for cooling the resin discharged from the discharge port of the die. It is possible.

That is, the present invention does not observe the position of the floss l-line or the shape of the resin, but rather monitors the pressure a5 and temperature of the molten resin, which are the causes of the changes, as well as the atmospheric temperature of the space where the resin is discharged. By focusing on parameters, detecting them, and using them for control, highly accurate control is possible.

The above-mentioned phenomenon of rising or falling of the line from Floss 1 occurs due to the rise or fall of the temperature and pressure horn of the molten resin discharged from the discharge port of the die, and also due to the shrinkage or fall of the resin shape. The change of expansion is
This is caused by the temperature of the discharged resin and the ambient temperature of the space in which it is discharged.

〔Example〕

Embodiments of the present invention will be described below with reference to FIG.

Fig. 1 shows an embodiment of the resin molding apparatus according to the present invention, and shows an extruder 28 in which the 1st hopper 27, which supplies resin 26 to the second side, has been removed. A cylinder 29 is provided inside to accommodate the resin 26,
Furthermore, a screw conveyor 30 for conveying the resin 26 at a predetermined pressure is built inside. Further, heaters 31 for melting the resin 26 are attached to the outer peripheries of the two cylinders at a plurality of locations in the axial direction, and below the extruder 28, the cylinders 26
A cooling blower control device 57 is connected to the cooling blower 32 for controlling the drive of the cooling blower 32.

The screw conveyor 30 is configured to be rotated by a motor 36. In other words, extrusion m2
Between the pulley 33 attached to the input shaft of the motor 36 and the pulley 35 attached to the drive shaft of the motor 36, the bells 1 to 34
The winding is connected with a spoon. screw conveyor 30
is rotationally driven by the driving force of this motor 36, and conveys the resin 26 at a predetermined pressure toward a die 39. ) 1. Between the screw conveyor 30 and the head 37 installed on the resin 26 outlet [1 side is the resin 26.
A screen 38 is provided to prevent impurities, dust, etc. from flowing into the die 39. A feed pipe 58 is provided at the extrusion port of the head 37 of the extruder 28.
for example, a die 39 for forming a Chicobra film.
The inlet portion 40 of the die 39 is removably connected (1-3).The upper surface of the die 39 has an annular discharge port 39a for discharging the molten resin 26 into a thin cylindrical shape and an annular discharge port 39a of the die 39. An air jet port lI2 for blowing the resin 26 is formed to jet air sent from an air supply port I411 formed below. An annular cooling air supply device 43 is disposed outside the outlet 39a, and this cooling air supply device 43 supplies cooling air for cooling the resin 26 discharged from the discharge port 39a. A blower 45 having an air conditioner 8 is connected via a branch pipe 44.

Further, above the cooling air supply device 43, a guide plate 46 and a pinch roller 47 are arranged to gradually overlap the resin 26 cooled by the cooling air supply device 43 in a planar shape. A winding roller 48 is provided on the downstream side of the roller 47 for winding up the resin 26 superimposed in a planar shape.

At the inlet portion 39a of the die 39, there is a resin pressure sensor/4 for detecting the pressure horn and temperature of the molten resin 26.
9 and a resin temperature sensor 50 are attached, and each of these sensors is connected to an arithmetic device 51 that performs a calculation based on the detected value.
The screw conveyor 3 includes a heater control device 52 for controlling the drive of the heater 31 based on the calculated value.
The heater 31 and the motor 3 are connected to a Tanabata control device 53 for controlling the drive of the heater 36 that drives the heater 31 and the motor 3.
6 is controlled.

On the other hand, in the space where the resin 26 discharged from the discharge port 39a of the die 39 exists, a temperature sensor 54 for detecting the ambient temperature of this space is disposed. is connected to a calculation device 55 that performs calculations based on the detected values, and further connected to this calculation device 55 is a blower control device 56 that controls the drive of the blower/45 based on the calculated values. has been done. The drive of the blower 45 is controlled by a control signal from the blower control device 56.

Next, the operation of this embodiment will be explained.

The resin 26 inputted from the hopper 27 of the extruder 28 is melted by the amount of heat from the heater 31 while being conveyed through the two cylinders by the screw conveyor 30, passes through the screen 38, and is then extruded from the extrusion port of the head 37. , and then the inlet portion 39a of the die 39 via the delivery pipe 38.
sent to. Then, the molten resin 26 is formed into a cylindrical shape by the die 39 and is discharged upward from the discharge port n 39 a, and the die 3 is discharged from the air supply port 41.
Air is supplied into the cylindrical film made of the molten resin 26 from the air outlet 42 at a predetermined pressure, thereby blowing the resin 26. Further, cooling air is supplied to the air supply device 43 by driving the blower 45 at a predetermined rotation speed, and this cooling air is jetted from the cooling air supply device 43 toward the resin 26. This cools the resin 26 discharged from the discharge port 30a of the die 39.

On the other hand, the resin pressure sensor 49 detects the pressure of the molten resin 26 sent from the extruder 28 at any time, and sends the detected value as a signal to the arithmetic unit 51. This calculation device 51 calculates the sent signal, and if the calculated pressure value is different from a preset reference pressure, it sends a signal to the motor control device @53, and the molten resin 26 The rotational speed of the motor 36 is changed so that the pressure becomes equal to the reference pressure. That is, if, for example, the screen 38 becomes slightly clogged, the pressure of the molten resin 26 decreases and the pressure detected by the resin pressure sensor 49 becomes low. If the pressure detected in this way is ~b lower than the reference pressure, a control signal is sent to the motor control device 53 to increase the rotational speed of the screener conveyor 30, and the motor control device 53 controls this control. The rotational speed of the motor 36 is increased based on the signal. On the other hand, if the detected pressure is higher than the reference pressure, the control is reversed to the above and the rotational speed of the motor 36 is reduced.

Next, the resin temperature sensor 50 detects the temperature of the molten resin 26 sent from the extruder 28 at any time, and sends the detected value to the arithmetic unit 51 as a signal. This computing device 5
1 calculates the sent signal in the same way as above, and if the calculated temperature value is different from the preset reference temperature, sends a signal to the heater control device 52 to adjust the resin temperature. The heater 31 is adjusted so that the temperature is equal to the reference temperature.
on/off or control the amount of electricity supplied to the heater.

Here, if the molten resin humidity becomes too high and the temperature must be lowered immediately, the cooling blower control device 57 is also sent a control signal as necessary. Control may be performed so that the blowers 32 are driven together.

Next, the ambient temperature sensor 54 detects the ambient temperature of the space in which the resin 26 discharged from the discharge port 40 of the die 39 is present, and sends the detected value as a signal to the arithmetic unit 55. This computing device @55 computes the sent signal, and if the computed temperature value is different from the preset reference temperature, it sends a signal to the blower control device 56. The rotation speed of the blower 45 is changed based on the signal. That is, the calculation device 55 calculates the amount of cooling air corresponding to the change in ambient temperature, and based on this, a signal is sent to the blower control device 56 to increase or decrease the rotation speed of the blower 45.

As described above, according to this embodiment, changes in the pressure and temperature of the melted resin and the ambient temperature of the space into which the resin is discharged are relatively gradual, and it is possible to easily perform accurate measurements. Since resin molding conditions are controlled using parameters, it is possible to grasp changes in molding conditions at any time without using complicated parameter measuring devices or calculation devices, and based on this grasped information, Molding conditions can always be controlled with high precision.

In addition, in this example, a calculation device connected to a resin pressure sensor and a resin temperature sensor, and a device connected to an ambient temperature sensor are provided separately, but these are summarized. It goes without saying that the detection signals from all the sensors may be input into one computing device to perform control. Further, in this embodiment, a die for forming a tubular film is used as the die, but any die such as a die for forming a flat film may be used.

The present invention is not limited to the embodiments described above, and various changes can be made as necessary.

〔Effect of the invention〕

As described above, in the resin molding apparatus according to the present invention, the pressure and temperature of the molten resin and the ambient temperature of the space where the resin is discharged change slowly and can be easily and accurately measured. By using parameters to control the resin pressure, resin temperature, and ambient temperature so that they are always constant, it is possible to accurately grasp and control the state of the resin during molding, which improves quality.
It becomes possible to automatically mold a certain resin with high quality. Furthermore, since the detection device and calculation device are relatively simple, the molding device itself can be made inexpensive.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an embodiment of a resin molding apparatus according to the present invention, and FIGS. 2 to 6 are schematic diagrams showing conventional resin molding apparatuses. 26...Resin, 28...Extruder, 30...Screw conveyor, 31...Heater, 36...7-Ta, 3
9...Die, 39a...Discharge port, 41...Air supply [1, 42...Air jet port, 7'13...Air supply device, 45...Pro 1), /I9...・Resin pressure range
50...Resin temperature sensor, 51.55...Arithmetic unit, 52...Heater control device, 53...Motor control device, 54...Atmosphere thirst sensor, 5G...B[
1wa control headpiece. Applicant's agent Shunsuke Nakao Figure 2 Figure 4 Figure 3 Figure 6

Claims (1)

[Claims] A die having a discharge port for forming and discharging the molten resin into a predetermined shape is connected to an extruder having a heater for melting the resin and a resin transport means for transporting the molten resin at a predetermined pressure. , in a resin molding apparatus comprising a cooling air supply device disposed near the discharge port of the die for cooling the resin discharged from the discharge port, pressure detection means for detecting the pressure of the molten resin; and resin temperature detection means for detecting the temperature of the molten resin;
An atmospheric temperature detection means for detecting the atmospheric temperature of the space into which the molten resin is discharged, and a control means for generating a control signal based on the values detected by each of these detection means, A resin molding apparatus characterized in that driving of at least one of the heater, the resin conveying means, and the air supply device is controlled based on a control signal from the means.