JPH07186230A - Device and method for controlling injection molding - Google Patents

Abstract

PURPOSE:To provide a device and a method for controlling injection molding in which it is distinguished rapidly and surely whether molding is good or bad during an injection molding work. CONSTITUTION:An injection molding machine 100 and a mold 101 are operated by an operating means 102. The temperature of a molding in the mold 101 is measured by a measuring means 103 and outputted to a controlling means 105. A temperature-comparing period is set up by a setting means 106. The injection molding machine 100 and the mold 101 are operated by the controlling means 105 to preliminarily perform molding work in a plurality of times. An allowable temperature pattern is formed by the measured temperature sent from the measuring means 103 and housed in a storing means 104. The controlling means 105 compares the allowable temperature pattern with the measured temperature obtained by a molding working operation performed after the preliminary operation concerning the temperature-comparing period. When the measured temperature deviates from the allowable temperature pattern, it is judged that molding is abnormal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding control apparatus and control method, and more particularly to a control apparatus and control for controlling an injection molding apparatus for injecting molten resin from an injection molding machine into a mold for molding. Regarding the improvement of the method.

[0002]

2. Description of the Related Art Conventionally, in an injection molding apparatus for injecting a molten resin from an injection molding machine into a mold to process a molded product such as resin or glass, the molten resin filled in the mold is held for a certain period of time. It is cooled and solidified, and then the molding process is performed in the process of taking out the molded product from the mold, but it is common to take out the molded product from the mold after the temperature falls below a predetermined temperature so as not to deform after taking it out. Is. As a technique for determining the holding pressure cooling period of the molded product in the mold, for example, Japanese Patent Laid-Open No.
As shown in Japanese Patent Publication No. 25555519, a cooling end temperature is set in advance, the temperature of a molded product in a mold is detected and compared with the set temperature, and when they match, the molded product is considered to be cooled. There is a technology to take out.

Further, as a technique for discriminating whether or not a molded product in a mold is suitable for molding, a good product is molded and processed only once to obtain the relationship between temperature and pressure, and the measured temperature of the molded product in the actual molding process is used. There is a method in which the relationship between the pressure is compared with the relationship between the temperature and the pressure of the non-defective product under the molding process to determine the quality. As one example thereof, as disclosed in JP-A-1-136712, the pressure (P) and the temperature (T) are grasped, and a reference value obtained from the relationship between them is compared with the temperature and pressure of the molded product of the mold. However, there is a technique for determining the quality of molding. Further, although not shown, as another example, when the molten resin filled in the mold is solidified by the holding pressure cooling action, the existing pressure (P), volume (V) and temperature (T) are present. Some control the holding pressure from related data.

[0004]

However, the above-mentioned first conventional structure is used to take out the molded product from the mold when the resin temperature in the mold matches the preset temperature, which is used. The setting temperature must be individually and empirically finely changed depending on the resin, the shape of the cavity in the mold, etc., and the setting is complicated. If the set temperature is too high and it is not suitable for the material and shape of the molded product, deformation will occur even after taking out the molded product from the mold, while if the set temperature is too low, the molded product will be more than necessary. Since it is cooled and taken out, the molding (shot) for one piece takes too long, and so-called cycle loss cannot be ignored.

Further, when a part of the molded product is in the shape of a thin pipe, the resin shrinking into the pin-shaped mold penetrating the inside easily bites and is easily broken, and the resin left in the mold after being broken. There is a drawback that the reliability and the productivity are likely to be lowered, such as the time required for removing them. As described above, it is important to set the temperature at which the molded product is taken out from the mold, but on the other hand, there are many unstable factors, and it has been conventionally difficult to set the temperature to an appropriate value.

Further, in the above-mentioned second conventional structure, the relationship between the pressure (P), the volume (V) and the temperature (T) is effective in that the temperature of the molten resin is sufficiently lowered.
At the stage where resin shrinkage progresses to the occurrence of sink marks, the relationship between pressure (P), volume (V) and temperature (T) is likely to become unstable at a high temperature stage such as the initial holding pressure, so that good product molding can be performed. There is also a possibility that it may be erroneously determined as molding abnormality. And
Also in the comparison period, there is a demand for a configuration that enables determination as early as possible in order to prevent damage to the mold in the event of an abnormality and to reduce waste of the injection process.

Furthermore, in the above-mentioned third conventional structure, there is a drawback that the holding pressure is not effective for all stages. For example, in the molding process, there are a stage immediately after filling the mold with resin or the like and a stage in which the molded product shrinks. The relational data of pressure (P), volume (V) and temperature (T) is It is effective in the shrinking stage of the product, but when the solidified layer of the molded product is formed immediately after filling and sufficient pressure is applied to the inside of the molded product to improve the transferability to the cavity shape of the mold, the related data Is not effective. Rather, simply temperature (T)
Therefore, it is more effective to detect the injection pressure from the above relationship, and such a structure has been desired.

Therefore, the present inventor determines the upper limit of the coercive pressure by the thickness of the solidified layer of the molded product which is in contact with the mold from the viewpoint of preventing the deformation and burrs of the molded product. Is simply due to the temperature of the molded product and the mold, and the temperature of the mold is almost constant during continuous molding and is almost stable. We have found a structure that can determine the holding pressure pattern of a molded product. In many cases, the injection pressure is used until the mold is filled with the molten resin, and the injection pressure after the cavity of the mold is filled with the molten resin is called the holding pressure.
For the sake of convenience, the holding pressure is referred to as the injection pressure in this specification. same as below.

The present invention has been made in order to solve such a conventional drawback, and an object thereof is to provide an injection molding control device and a control method capable of promptly and reliably determining the quality of a molded product under injection molding. And Another object of the present invention is to provide an injection molding control device and control method that can obtain an appropriate injection pressure and cooling period.

[0010]

As shown in FIG. 1, the first construction of the present invention for solving the above-mentioned problems is, as shown in FIG. 1, the injection operation and mold of an injection molding machine 100 for injecting a molten resin. Operating means 102 for opening and closing 101, and measuring means 103 for measuring the temperature of the molded product in the mold 101.
A storage means 104 for storing a temperature pattern in the molding process of the molded product, a control means 105 for controlling the molding processing operation of the injection molding machine 100 and the mold 101 via the operation means 102, and the mold. There is a setting means 106 for setting a period during which at least a solidified layer is not formed after the molten resin is filled therein as a temperature comparison period.

In addition, the control means 105 controls the measuring means 10 by performing a plurality of preliminary molding processing operations.
The allowable temperature pattern based on the measured temperature obtained from No. 3 is stored in the storage means 104 as the temperature pattern, and the measuring means 1 is operated by the molding operation after the preliminary operation.
The measured temperature obtained from No. 03 and the allowable temperature pattern are compared within the temperature comparison period, and when the measured temperature is within the allowable temperature pattern, it is determined to be normal and the molding process of the injection molding machine and the mold is normal. Time control is performed, and when the measured temperature deviates from the allowable temperature pattern, it is determined that molding is abnormal.

In the first construction, the control means 105 may be formed so as to control the injection pressure into the mold to be lowered when it is judged that the molding is abnormal. Further, according to the second configuration of the present invention, with reference to FIG. 1, an operating unit 102 for performing the injection operation of the injection molding machine 100 for injecting the molten resin and the opening / closing operation of the mold 101, and the inside of the mold 101. Measuring means 103 for measuring the temperature of the molded product and the injection pressure of the injection molding machine, storage means 104 for storing the measured temperature and the measured injection pressure, and the temperature at which the molten resin partially solidifies in the mold 101. And a control means 105 for changing the injection pressure of the mold 101 via the operating means 102 when the temperature measured by the measuring means 103 reaches the temperature set by the setting means 106. is doing.

In the second structure, the setting means 1 is used.
The set temperature set in 06 is set as the solidified layer forming temperature of the molded product, and the control means 105 may be formed so as to increase the injection pressure. Further, in the second configuration, the set temperatures set by the setting means 106 are set as the solidified layer forming temperature and the gate portion solidifying temperature of the molded product, and the change in the measured temperature changes from the solidified layer forming temperature to the gate portion solidifying temperature. It is advisable to form the control means 105 so as to control the injection pressure to be reduced in accordance with the temperature change tendency during the period. Furthermore,
In the second configuration, the setting means 106 is formed so that the temperature decrease gradient at the time of complete solidification of the molded product can be set, and the mold is operated when the measured temperature change reaches the temperature decrease gradient at the time of complete solidification of the molded product. The control means 105 may be formed so as to control the cooling of the molded product by 101.

The injection molding control method according to the present invention is
Molten resin is injected from the injection molding machine into the mold to perform multiple preforming processes, and the temperature change of the molded product in the preforming process is measured and stored as an allowable temperature pattern. The temperature comparison period in which at least the solidified layer is not formed after the molten resin is filled inside and the partial solidification temperature of the molten resin in the mold are preset, and the molten resin is injected from the injection molding machine into the mold. The temperature change of the molded product is measured during the main molding process and compared with the above allowable temperature pattern within the temperature comparison period, and the measured temperature of the molded product whose measured temperature is within the allowable temperature pattern is solidified. When the layer forming temperature is reached, the injection pressure to the mold is changed and then the pressure is reduced to perform the forming.

In such an injection molding control method, when the temperature decrease gradient at the time of complete solidification of the molded product is set in advance and the measured temperature change becomes smaller than the temperature decrease gradient at the time of complete solidification of the molded product, It is advisable to finish cooling the molded product with the above-mentioned mold.

[0016]

In the first construction provided with such means, the control means 105 is operated by the operation means 102 and the injection molding machine 100 is operated.
When the mold 101 is preformed, the measuring unit 103 measures the temperature of the molded product in the mold 101, and the control unit 105 creates an allowable temperature pattern based on the measured temperature and stores it in the storage unit 104. The control unit 105 compares the measured temperature obtained by the molding process after the preforming process by the control unit 105 with the allowable temperature pattern for the temperature comparison period, and when the measured temperature is within the allowable temperature pattern, it is determined as normal. The control means 105 enables normal control of the molding operation, and when the measured temperature deviates from the allowable temperature pattern, it is determined that molding is abnormal.

In the first configuration, in the configuration in which the control means 105 is formed so as to control the injection pressure of the mold 101 to be lowered when the molding abnormality is determined, the mold 101 is automatically operated when the molding abnormality is determined. The injection pressure to the cylinder decreases. In the second configuration according to the present invention, the injection molding machine 100 and the mold 1 are controlled by the control means 105 via the operation means 102.
When 01 is subjected to molding processing operation, the measuring means 103 measures the temperature of the molded product in the mold 101 and the injection pressure of the injection molding machine, and is stored in the storage means 104 and brought to the partial solidification temperature set by the setting means 106. When the control unit 105 determines that the measured temperature has reached, the control unit 105 causes the operating unit 102 to operate.
The injection pressure of the mold 101 is controlled to change via the.

In the second configuration, the setting means 1
The partial solidifying temperature set in 06 is set as the solidified layer forming temperature of the molded product, and the control means 10 is controlled so as to increase the injection pressure.
In the structure of forming 5, the injection pressure rises after the solidified layer is formed on the molded product in the mold 101, and the injection pressure effectively acts. Further, in the second configuration, the partial solidification temperature set by the setting means 106 is set as the solidified layer forming temperature and the gate portion solidifying temperature of the molded product, and the change in the measured temperature changes from the solidified layer forming temperature to the gate portion solidifying temperature. If the control means 105 is formed so that the injection pressure is controlled to be reduced in accordance with the temperature change tendency during the period, the pressure inside the mold 101 is smoothly reduced.

Furthermore, in the second structure, when the measured temperature change of the molded product reaches the temperature decrease gradient at the time of complete solidification, the cooling completion by the mold 101 is controlled, and the temperature decrease gradient is used. Since the end of cooling can be detected regardless of the type and shape of the molded product, the molded product can be taken out from the mold 101 at an appropriate time while suppressing insufficient cooling or supercooling.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. Before describing the injection molding control device according to the present invention, an injection molding device including this molding control device will be described, and an injection control method will also be described in the process of describing the injection molding control device of the present invention.

FIG. 2 is a schematic view showing an injection molding apparatus including an injection molding control device according to the present invention, and the same parts as those in FIG. 1 are designated by the same reference numerals. In FIG. 2, the injection molding machine 100 is an in-line screw type having a heating cylinder 1 that is a main body portion and a screw 3 that is inserted into the heating cylinder 1.
The tip of the nozzle is the nozzle 5. It goes without saying that the injection molding machine 100 has various configurations other than the in-line screw type. The screw 3 extends from the injection cylinder 7 so as to be inserted into the heating cylinder 1 toward the nozzle 5, and is driven to rotate by a motor or the like (not shown) and heated by the drive unit 9 moving the injection cylinder 7 back and forth. It moves forward or backward in the cylinder 1.

The injection cylinder 7 is provided with an injection pressure sensor 13 which outputs a measurement signal for measuring the injection pressure to the injection molding control device 11. On the outer periphery of the heating cylinder 1, a hopper 15 is arranged at the center in the axial direction and communicates with the inside. The molding resin material supplied from the hopper 15 is heated and melted in the heating cylinder 1, and the screw 3 is advanced. As a result, the molten resin is injected under pressure from the nozzle 5 into the mold 101. Mold 1
01 is formed by combining the fixed mold 17 and the movable mold 19. The fixed mold 17 and the movable mold 19 form a cavity 21 corresponding to the outer shape of the molded product.
The molten resin is injected and injected from the nozzle 5 through the gate 17a provided in the nozzle 7.

The movable die 19 is connected to the die clamping cylinder 23, and is moved by the forward / backward movement of the drive unit 25.
Can be clamped and opened. The mold 101 is
Molded product temperature sensor 27 that measures the temperature of the molded product in the cavity 21 and outputs a measurement signal to the injection molding control device 11.
Alternatively, an in-mold pressure sensor 29 that measures the in-mold pressure of the mold 101 and outputs a measurement signal to the injection molding control device 11 is arranged with the measurement section facing the cavity 21. For convenience, the molded product temperature sensor 27 and the mold internal pressure sensor 29 are not shown in the mold 101.
It is shown in a state of being taken out from the outside.

Around the heating cylinder 1, there is a heating means such as a band heater for heating the heating cylinder 1 and a cooling device for cooling with a cooling medium. The heating cylinder 1 measures the temperature of the internal molten resin. A temperature sensor and the like are arranged, and a temperature measuring sensor and a pressure sensor that measure the temperature and pressure of the molten resin injected from the heating cylinder 1 are also arranged in the nozzle 5, but this is not an essential part of the present invention. Illustration is omitted. Further, a heating device such as a heater, a cooling device using a cooling medium, and a temperature sensor for temperature detection are also arranged in the mold 101, but they are also omitted in the drawing.

The injection molding control device 11 has a function of inputting each temperature of the heating cylinder 1, the nozzle 5, the mold 101 and the molded product in the mold 101 as a temperature measurement signal, the injection cylinder 7, the nozzle 5 and the mold 101. The function of inputting the internal pressure as a pressure measurement signal, the function of adjusting the temperature of the heating cylinder 1 and the mold 101 via the heating means and the cooling means, the injection cylinder 7 and the mold clamping cylinder 23 via the drive units 9 and 25. It has a function of controlling injection pressure and mold clamping or mold opening by operating, and has a main function according to the present invention as described later.

Next, the first structure of the injection molding control device 11 of the present invention will be described. FIG. 3 is a block diagram showing the injection molding control device 11 of the present invention. In FIG. 3, a control unit 31 is a main calculation unit and a main display and operation unit of the injection molding control device 11, and includes a CPU 31a and a C unit.
ROM 31b storing the operation program of PU 31a and I / O (input / output unit) 31 as an interface
1, which corresponds to the control means of FIG. 1 mainly including a microcomputer, includes a temperature measurement unit 33, a pressure measurement unit 35, a learning start setting unit 37, a learning data storage unit 39, a setting unit 41, a display unit 43, and a temperature operation. It is connected to the part 45, the injection operation part 47, and the alarm output part 49, and controls them.

The temperature measuring unit 33 is composed of, for example, a multiplexer, an amplifier and an A / D converter, and switches the inputs from a plurality of temperature sensors according to a switching signal from the control unit 31 and outputs it to the control unit 31. To do. For example, it has a function of taking in the molded product temperature from the molded product temperature sensor 27 of FIG. 2 every 100 ms and outputting it as a digital signal to the control unit 3. The same applies to other temperature measurement signals, but the description thereof is omitted because it is not an essential part of the present invention.

Like the temperature measuring unit 33, the pressure measuring unit 35 is composed of a multiplexer, an amplifier and an A / D converter, and switches the inputs from a plurality of pressure sensors in response to a switching signal from the control unit 31 to select the control unit. It outputs to 31 and corresponds to the measuring means 103 in FIG. For example, the measurement signals from the mold pressure sensor 29 and the injection pressure sensor 13 of FIG.
It has a function of alternately taking in every ms and outputting to the control unit 31 as a digital signal.

The learning start setting section 37 is a mechanical operation means such as operation keys or an electronic setting means online from the outside, and is used for preforming a non-defective product in order to determine an allowable temperature pattern which will be described later. The start or end of the process is externally instructed to the control unit 31, and the allowable temperature pattern is determined based on the temperature change obtained through the molded product temperature sensor 27 in this preforming. Details will be described later. The number of times of preforming may be stored in the ROM 31b in the control unit 31 described above as an operation program so that it can be executed in addition to inputting the number of times of preforming. For the reason that it is more certain that the preforming is performed while confirming, it is practically preferable to instruct the start or end each time by operating the learning start setting unit 37.

The learning data storage unit 39 stores the allowable temperature pattern and the injection pressure taken from the pressure measuring unit 35 under the control of the control unit 31, and corresponds to the storage means 104 in FIG. Similar to the learning start setting unit 37, the setting unit 41 is a mechanical operation unit such as an operation key or an electronic setting unit online from the outside, and sets the allowable temperature pattern and the temperature change in the mold 101. Temperature comparison period to be compared, correction value or correction function of allowable temperature pattern, solidified layer formation temperature (T1) of outer skin of molded product, gate solidification temperature (T2) which is solidified temperature near gate 17a of molded product, molded product In addition to the temperature decrease gradient (ΔT) at the time of complete solidification, the basic set values of the controller such as the set value SV are set and output to the control unit 31, and they are stored in the RAM or the like. It corresponds to the learning start setting unit 37 and the setting means 106 in FIG.

The temperature comparison period set by the setting unit 41 is between arbitrary points A and B as shown in FIG. 4, for example, and the allowable temperature pattern is compared with the actual measured temperature during the main forming process. It is a period. The point A in the temperature comparison period to be described later with reference to FIG. 4 is preferably an arbitrary time point or state after the injection molding is started and after the molten resin is fully filled in the mold 101, and the point B is after the point A. It is preferable that the measured temperature of the molded product does not reach the solidified layer forming temperature (T1).

The display unit 43 displays the allowable temperature pattern stored in the learning data storage unit 39, the temperature and pressure measured by the temperature measuring unit 33 and the pressure measuring unit 35, the cooling end temperature of the molded product, or the mold 101. It is an electronic display device for displaying a measured value or a calculated value related to a normal controller operation in the control section 31, in addition to the mold opening temperature, and is a display unit 1 in FIG.
It corresponds to 07. The temperature operation unit 45 is based on the operation amount MV from the control unit 31, and the heating cylinder 1 and the mold 1 in FIG.
No. 01 heating / cooling device is operated to control the temperature of them.

The injection operating section 47 is the injection molding machine 1 shown in FIG.
00 and the driving units 9 and 25 for driving the die 101 are operated, and the driving units 9 and 25 operate by opening and closing, for example, a hydraulic oil supply pump or a servo valve based on an instruction from the injection operation unit 47 to perform injection. The cylinder 7 and the mold clamping cylinder 23 are moved back and forth. Mainly those temperature operating unit 45 and injection operating unit 4
7 and the drive units 9 and 25 correspond to the operation means 102 in FIG. The alarm output unit 49 has a control unit 31 as described later.
Outputs an alarm signal when it determines that the molded product is abnormal, and an external buzzer or lamp (not shown) is sounded or turned on based on the alarm signal. This alarm signal is output when there is an abnormality in the injection molding machine 100 or the injection molding control device 11 itself in addition to the abnormality in the molded product.

The control unit 31 calculates, for example, PID from the deviation between the temperature measurement value PV from the temperature measurement unit 33 and the set value SV from the setting unit 41 and outputs the manipulated variable MV to the temperature operation unit 45 for heating. It has a function of adjusting the temperature of the cylinder 1 and the mold 101, and also has a measured value PV or a set value SV thereof.
And the like are displayed on the display unit 43, the injection cylinder 7 and the mold clamping cylinder 23 are operated from the injection operation unit 47 via the driving units 9 and 25, and the injection pressure and the mold clamping mold opening are controlled.
In addition to the basic control function of the molding operation by the injection operation device, it has the following functions. That is, the control unit 3
1 is an instruction from the learning start setting unit 37, and the injection molding machine 100 and the mold 1 in FIG.
01 is preliminarily operated a predetermined number of times, and has a function of forming an allowable temperature pattern based on the change in the measured temperature obtained from the temperature measuring unit 33 and storing it in the learning data storage unit 39.

This allowable temperature pattern stores the time-molded product temperature change, for example, from ten or more shots, regarding the temperature change of the molded product in relation to the time elapsed after the start of injection or during the injection, and at the time of molding a good product. The allowable temperature range is the allowable temperature pattern with respect to the passage of time. This temperature width is preferably a pattern of maximum and minimum values of individual measured temperatures that change with the passage of time during molding of a non-defective product. It is preferable that a negative correction value or a correction function is input and the allowable temperature pattern is formed from the corrected value and stored in the learning data storage unit 39.
In this configuration, for example, the allowable temperature pattern can be formed from the temperature corrected by + 2 ° C. for the maximum value and −1 ° C. for the minimum value.

Further, in addition to this, an average value may be obtained and a certain range, for example, ± 5 ° C. may be adjusted and set, and the allowable temperature range is statistically determined by using the 3 sigma value. There is also a method to do. The control unit 31 also controls the injection molding machine 100 and the mold 101 in FIG.
When the main operation is performed, the measured temperature obtained from the temperature measuring unit 33 is compared with the allowable temperature pattern stored in the learning data storage unit 39, and the measured temperature of the molded product in the mold 101 is compared with the temperature comparison period. When the temperature is within the allowable temperature pattern, normal control of the molding operation is performed, and when the temperature exceeds the allowable temperature pattern, the molded product is determined to be an abnormal product and an alarm signal is output from the alarm output unit 49. It has a function.

In addition, the control unit 31 operates the drive unit 9 shown in FIG. 2 through the injection operation unit 47 when the molding abnormality of the molded product is determined, and changes the injection pressure from the nozzle 5 into the safe range. have. As this safety region, a decompression width of about 1/2 to 1/3 of a normal injection pressure that does not cause an extremely short shot is preferable. Generally, if the injection pressure is set to zero at a temperature at which the gate portion of the molded product does not solidify, a short circuit of the molded product is too strong, and a part of the molded product is likely to remain in the cavity 21. is there. In order to prevent this, the injection pressure should be 1/2 to 1 of the normal pressure.
It is preferable to reduce the pressure to about / 3, and the injection pressure may be set to zero after the gate portion is solidified.

Next, the operation of such a first configuration will be described with reference to FIG.
Will be briefly explained. FIG. 4 is an operating characteristic diagram in the first configuration of the present invention, in which the vertical axis represents the molded product temperature and injection pressure, the horizontal axis represents time, the one-dot chain line represents the allowable temperature pattern, and the solid line represents the molded product. The temperature, and the broken line shows the transition of the injection pressure at the time of abnormal molding. When the control unit 31 operates the injection molding machine 100 and the mold 101 of FIG. 2 a predetermined number of times through the injection operation unit 47 by operating the learning start setting unit 37 of FIG. 3, the temperature measurement unit is operated according to the number of preforming processes. Since the measured temperature is obtained from 33, the control unit 31 creates an allowable temperature pattern such as the one-dot chain line in FIG. 4 based on the measured temperature and stores it in the learning data storage unit 39.

After that, when an instruction for the main forming process is issued from the setting unit 41 or the like, the control unit 31 operates the injection molding machine 100 and the mold 101 through the injection operating unit 47 to perform the main forming process, and the temperature measuring unit 33. The measured temperature obtained through the control unit 31 is taken into the control unit 31, and the measured temperature is the allowable temperature stored in the learning data storage unit 39 for the temperature comparison period (point A-point B) of FIG. Compared with the pattern, the control unit 31 performs normal control of the molding operation when the measured temperature during the main operation is within the allowable temperature pattern, and when the measured temperature during the main operation exceeds the allowable temperature pattern, the control unit Reference numeral 31 determines that the molded product is an abnormal product, and outputs an alarm signal from the alarm output unit 49. Further, when determining abnormal molding, the control unit 31 controls the driving unit 9 in FIG.
As indicated by the broken line, the injection pressure in the mold 101 is reduced to change to a safe range.

As described above, in the first configuration according to the injection molding control device of the present invention, the control unit 31 operates the injection molding machine 100 and the mold 101 via the injection operation unit 47 to perform a plurality of preliminary molding processes. The control unit 31 captures the temperature of the molded product in the die 101 in this preforming process, stores and stores the change as an allowable temperature pattern, and the die 101 taken in during the forming process after the preforming process. With respect to the temperature of the molded product in the inside, the control unit 31 during the temperature comparison period during which the solidified layer is not formed after the mold 101 is filled with the molten resin.
Is compared with the allowable temperature pattern, and if it is within the allowable temperature pattern, the normal molding operation is performed, and if the molded product temperature deviates from the allowable temperature pattern, it is judged as abnormal molding. The temperature change pattern for the non-defective product is set by simply performing multiple molding processes, and after the molten resin is filled during the main molding process, it is possible to quickly and reliably and stably determine the quality of the molded product. Can be suppressed.

In particular, this configuration is useful when the temperature of the molten resin flowing in immediately after the start of molding or after the interruption of molding or the temperature of the details of the mold 101 is significantly different from the normal state. Therefore, when using the molded product temperature as a factor of injection molding control, it is judged whether the molded product temperature is normal or abnormal during a certain period after the filling of the molten resin, and only the molded product with a normal shot is used. By using it for molding processing control, it is possible to prevent defective mixture and reduce waste of the injection process. Further, when the control unit 31 determines that the molding is abnormal, the control unit 31 operates the injection cylinder 7 via the injection operation unit 47 and the drive unit 9 to reduce the injection pressure of the mold 101 to a safe range, so that the mold 101 is damaged. In addition, the molded product remains in the mold 101 and the dead time for taking it out is eliminated, and the reliability and the molding efficiency are high.

By the way, the above-mentioned temperature comparison period in the present invention between points A and B is an arbitrary point within a period in which at least a solidified layer is not formed after the molten resin is fully filled in the mold 101. , For example, the elapsed time after the temperature or injection pressure of the molded product exceeds a certain value,
A certain elapsed time from point A may be set as point B. further,
The points A and B are not only the time elapsed from the reference point for setting the time, but also the temperature of the molded product, the mold internal pressure or the injection, as long as it does not reach the formation of the solidified layer after the molten resin is fully filled. It may be a point where the pressure is above a certain value, a point where the amount of change in the mold pressure or the injection pressure is below a certain value, or a combination thereof.

Next, the second configuration of the injection molding control device of the present invention will be described with reference to FIG. In FIG. 3, in addition to the functions described above, the setting unit 41 includes a partial solidification temperature of the molten resin in the mold 101, that is, a solidification layer forming temperature (T1) and a gate solidification temperature (T) of the molded product.
It has the function of setting 2). In addition to the functions described above, the control unit 31 has the following functions in addition to the function of calculating the temperature decrease gradient (ΔT) when the molded product is completely solidified. The data for calculating the temperature decrease gradient (ΔT) is set and stored, for example, from the setting unit 41 described above.

When the measured temperature of the molded product reaches the solidified layer forming temperature (T1), the control unit 31 controls the drive unit 9 via the injection operation unit 47 to preset the injection pressure of the injection cylinder 7. While increasing the pressure in the mold in the mold 101 by changing and controlling so that it becomes a different value, from the solidification layer formation temperature (T1) to the gate solidification temperature (T2) so-called gate seal,
Similarly, it has a function of controlling the drive unit 9 via the injection operation unit 47 and controlling the injection pressure of the injection cylinder 7 to be lowered in accordance with the temperature change tendency.

The degree of this reduction control is calculated by the control unit 31 using the following equation (1). P _Z = P × [(T _Z −T 2) / (T 1 −T 2)] × F (t) (1) In addition, in the equation (1), each symbol is as follows, and from the setting unit 41: Settings are stored. P _Z : Injection pressure at any desired time P: Injection pressure at solidified layer formation temperature (T1) of molded product T _Z : Measured temperature at any desired time T 1: Solidified layer formation temperature of molded product Set value (T1 is a sensor The temperature change amount due to the delay time of T .: T2: Set value of the solidification temperature of the gate of the molded product (T2 includes the margin temperature for completely completing the gate seal and the temperature change amount due to the delay time of the sensor.) F (t ): Pressure correction coefficient (takes a value of 0 to 1 as a function of time)

Further, when the change in the measured temperature is lower than the temperature decrease gradient (ΔT) at the mold opening temperature, the control unit 31 determines that the cooling of the molded product in the mold 101 is completed and outputs the cooling completion. It has a function of controlling the completion of cooling such as turning on, and operating the mold clamping cylinder 23 by the drive unit 25 via the injection operation unit 47 to move the movable mold 19 and control the mold opening of the mold 101.

Next, the operation according to the second structure will be briefly described with reference to FIG. FIG. 5 is a characteristic diagram for explaining the operation of the second configuration, in which the vertical axis represents molded product temperature, injection pressure, and mold internal pressure, the horizontal axis represents time, and the alternate long and short dash line represents mold internal pressure.
The solid line shows the temperature of the molded product and the dotted line shows the transition of the injection pressure. In FIG. 5, when a molding process instruction is issued from the setting unit 41, the control unit 31 performs a molding process operation of the injection molding machine 100 and the mold 101 via the injection operation unit 47, and the temperature measurement unit 33 and the pressure. The measurement temperature and the measurement pressure obtained through the measurement unit 35 are taken into the control unit 31, and when the control unit 3 determines that the measurement temperature has reached the solidified layer forming temperature (T1), the control unit 3 causes the injection operation unit 47. The drive unit 9 is controlled to drive the injection cylinder 7.
The injection pressure of is controlled to rise to a predetermined value.

When the control unit 31 changes the injection pressure, the change is controlled with reference to the measured pressure from the pressure measuring unit 35. In addition, the control unit 31 controls the drive unit 9 through the injection operation unit 47 from the solidified layer forming temperature (T1) of the molded product to the gate solidification temperature (T2) of the molded product to control the injection pressure of the injection cylinder 7. The decompression control is performed along with the decrease of the measurement temperature. Therefore, the in-mold pressure increases at the solidified layer forming temperature (T1) and then decreases. The change in injection pressure does not have to be directly proportional to the decrease in measurement temperature.

Further, when the measured temperature change of the molded product reaches the temperature decrease gradient (ΔT) at the time of complete solidification, the control unit 31 controls the completion of the cooling process of the molded product, and the drive unit 25 via the injection operation unit 47. It is possible to take out a molded product by controlling the mold clamping cylinder 23 and controlling the mold opening. As described above, in the second configuration, when the measured temperature of the molded product falls below the solidified layer forming temperature (T1), the control unit 31 causes the mold 101 to operate.
Since the internal injection pressure is controlled to rise to a predetermined pressure, burrs are less likely to occur in the molded product due to the solidified layer, and a molded product of good quality can be molded.

On the other hand, if the injection pressure is increased before the solidified layer forming temperature (T1) of the molded product is reached, pressure is applied without the solidified layer being formed, so that burrs are likely to occur. Further, the control unit 31 controls the solidified layer forming temperature (T
Since the injection pressure from 1) to the gate seal at the gate solidification temperature (T2) is decreased along with the temperature change, a molded product having a uniform wall thickness and good quality can be obtained. Generally, it is meaningless to have an injection pressure at the time of solidification of the gate part, so the injection pressure is lowered to zero or a very small value. By smoothly reducing the pressure until the gate portion is solidified, it is possible to suppress the occurrence of local uneven wall thickness, and from this point as well, a molded product of good quality can be formed.

Further, when the measured temperature change reaches the temperature decrease gradient (ΔT) at the time of complete solidification of the molded product and decreases, the control unit 31 determines the end of cooling and controls the mold closing cylinder 23 to open the mold. Therefore, the molded product can be taken out from the mold 101 at an appropriate time without insufficient cooling or supercooling. However, it is general to take out the molded product by opening the mold when the plasticizing of the resin in the heating cylinder 1 is completed and the cooling process of the molded product is completed.

Temperature drop gradient (Δ) when the molded product is completely solidified
Since T) is determined to some extent by the shape of the molded product and largely depends on the material of the molded product, the appropriate mold opening timing of the mold 101 can be set relatively easily and reliably. Regarding the determination of the mold opening based on the temperature decrease gradient (ΔT), a function of making a comparative judgment from the time when a certain time or more has elapsed after injection or the temperature of the molded product decreases to a certain temperature or less may be added. The time-up time may be added, assuming that the comparison operation with the temperature decrease gradient (ΔT) becomes uncertain.

Further, the determination of the temperature decrease gradient (ΔT) is determined as the completion of cooling of the molded product only when the measured temperature of the molded product is continuously lowered at a plurality of predetermined measurement points in order to prevent malfunction due to noise or the like. It may be configured to operate. In the second configuration, when the temperature of the molded product reaches the solidified layer forming temperature (T1), the injection pressure is increased. However, in a special case where warpage or deformation is important. In some cases, the injection pressure may be once reduced without increasing, and the control unit 31 may be formed to meet this.

By the way, in the present invention, the above-described first configuration or second configuration may be implemented independently, or the first and second configurations may be implemented together.
As in the case of the first configuration, the quality of the molded product is determined based on the comparison between the allowable temperature pattern by the pre-forming process and the measured temperature during the actual molding process, and the second configuration may be performed only for the molded product that is determined to be a good product. . This point will be explained by the control method as follows. In addition to the various effects described above, it becomes possible to take out a molded product determined to be normally molded from the mold 101 after an appropriate cooling period. The quality and productivity of can be improved.

That is, the molten resin is injected from the injection molding machine 100 into the mold 101 to perform a plurality of preforming processes,
While measuring the temperature change of the molded product in the mold 101 in this preforming process and creating and storing the allowable temperature pattern,
The temperature comparison period and the partial solidification temperature of the molten resin in the mold are set in advance, and the main molding process is performed by the injection molding machine 100 and the mold 101. The temperature change of the molded product is measured, and this measured temperature is compared with the allowable temperature pattern within the temperature comparison period.If the measured temperature is within the allowable temperature pattern, it is judged as normal molding, and this normal molded product is When the solidification temperature is reached, the injection pressure in the mold 101 is changed and then the pressure is reduced.

Moreover, also in this control method, the solidified layer forming temperature of the molded article or the mold 10 is used as the partial solidifying temperature.
It is possible to set the gate part solidification temperature of the molded product in 1 and further, when the temperature change of the molded product becomes small and the temperature gradient at the time of complete solidification of the molded product is reached, It is better to finish cooling.

[0057]

As described above, according to the first configuration of the present invention, a non-defective product is preformed for several to ten times and its temperature is
If the allowable temperature pattern is formed from the time pattern, it becomes possible to judge the quality of the molding from the time when an appropriate temperature has passed after the filling of the molten resin during the main molding process (shot). By using it, defective molded products can be eliminated easily and surely. In addition, in the first configuration, when the molding abnormality is determined and the injection pressure to the mold is controlled to be reduced, damage to the mold is avoided and the molded product is less likely to remain in the mold. It is possible to improve reliability and molding efficiency. In addition, the second configuration according to the present invention can appropriately control the injection pressure, which has been conventionally complicatedly determined by empirical factors and substitute-related factors, in accordance with the temperature change of the molded product in the mold and cooling control. As a result, the quality of the molded product is stable and improved. In the second configuration, if the partial solidification temperature of the molten resin is set as the solidified layer forming temperature of the molded product, and the injection pressure is controlled to increase when the measured temperature of the molded product reaches the solidified layer forming temperature, Molding with good quality without burrs can be performed. Further, in the second configuration, the partial solidification temperature is set as the solidification layer formation temperature and the gate portion solidification temperature of the molded product, and the injection pressure is set in accordance with the temperature change tendency between the solidification layer formation temperature and the gate portion solidification temperature. With the configuration in which the pressure is controlled under reduced pressure, a molded product having a uniform wall thickness and good quality can be obtained. Furthermore,
In the second configuration, when the measured temperature change of the molded product reaches the temperature decrease gradient at the time of complete solidification of the molded product, the cooling end of the molded product by the mold is controlled so that an appropriate cooling period can be obtained. After that, the molded product can be taken out, the cycle loss is reduced, and the production efficiency is improved. Further, according to the composite configuration of the first configuration and the second configuration, in addition to the individual effects described above, a molded product of good quality can be continuously and efficiently produced.

[Brief description of drawings]

FIG. 1 is a block diagram showing an outline of an injection molding control device according to the present invention.

FIG. 2 is a schematic view showing an injection molding control device of the present invention together with an injection molding device.

FIG. 3 is a block diagram showing an embodiment of an injection molding control device according to the present invention.

FIG. 4 is an operational characteristic diagram illustrating an operation in the first configuration of the injection molding control device of the present invention.

FIG. 5 is an operational characteristic diagram illustrating an operation in the second configuration according to the injection molding control device of the present invention.

[Explanation of symbols]

 1 Heating Cylinder 3 Screw 5 Nozzle 7 Injection Cylinder 9, 25 Drive Unit 11 Injection Molding Control Device 13 Injection Pressure Sensor 15 Hopper 17 Fixed Type 17a Gate 19 Movable Type 21 Cavity 23 Mold Clamping Cylinder 27 Molded Product Temperature Sensor 29 Mold Pressure Sensor 31 Control part (control means) 31a CPU 31b ROM 31c Interface (I / 0) 33 Temperature measurement part (measurement means) 35 Pressure measurement part (measurement means) 37 Learning start setting part (setting means) 39 Learning data storage part (storage means) ) 41 setting unit (setting unit) 43 display unit (display unit) 45 temperature operating unit (operating unit) 47 injection operating unit (operating unit) 49 alarm output unit 100 injection molding machine 101 mold 102 operating unit 103 measuring unit 104 storage Means 105 Control Means 106 Setting Means 107 Shows means

Claims (8)

[Claims] 1. An operating means for performing an injection operation of an injection molding machine for injecting a molten resin and an opening / closing operation of a mold for molding the injected molten resin, and a temperature of a molded product in the mold. An injection unit comprising a measuring unit for measuring, a storage unit for storing a temperature pattern in the molding process of the molded product, and a control unit for controlling the molding processing operation of the injection molding machine and the mold through the operation unit. A molding control device, which has setting means for setting a period during which at least a solidified layer is not formed after the molten resin is filled in the mold as a temperature comparison period, and the control means is a plurality of preliminary operations. The allowable temperature pattern based on the measured temperature obtained from the measuring means by the molding operation is stored in the storage means as the temperature pattern, and the molding operation after the preliminary operation is performed. The measured temperature and the allowable temperature pattern obtained from the measuring means by a working operation are compared within the temperature comparison period, and the injection molding machine and the injection molding machine are determined to be normal when the measured temperature is within the allowable temperature pattern. An injection molding control apparatus, wherein normal control of molding processing of a die is performed, and when the measured temperature deviates from the allowable temperature pattern, it is determined that molding is abnormal. 2. The injection molding control device according to claim 1, wherein the control means controls the injection pressure to the mold to be lowered when the molding abnormality is determined. 3. An operating means for performing an injection operation of an injection molding machine for injecting a molten resin and an opening / closing operation of a mold for molding the injected molten resin, and a temperature of a molded product in the mold and Measuring means for measuring the injection pressure of the injection molding machine, storage means for storing the measured temperature and the measured injection pressure, setting means for setting the temperature at which the molten resin is partially solidified in the mold, Control means for changing the injection pressure to the mold through the operating means when the temperature measured by the measuring means reaches the temperature set by the setting means. Control device. 4. The injection molding control device according to claim 3, wherein the set temperature set by the setting means is a solidified layer forming temperature of the molded product, and the control means controls the injection pressure to rise. 5. The set temperature set by the setting means is a solidified layer formation temperature and a gate solidification temperature of the molded product, and the control means changes a temperature between the solidified layer formation temperature and the gate solidification temperature. The injection molding control device according to claim 3, wherein the injection pressure is controlled to be reduced according to the tendency. 6. The setting means sets a temperature decrease gradient at the time of complete solidification of the molded product, and the control means uses the mold by the mold when the change in the measured temperature reaches the temperature decrease gradient. The injection molding control device according to claim 3, which controls the completion of cooling of the molded product. 7. A molten resin is injected into a mold from an injection molding machine to perform a plurality of preliminary molding processes, and a temperature change of a molded product in the mold during the preliminary molding process is measured to obtain an allowable temperature pattern. The temperature comparison period in which at least a solidified layer is not formed after the molten resin is filled in the mold and the partial solidification temperature of the molten resin of the molded product is preset, and the molten resin is melted from the injection molding machine. The temperature of the molded product is measured in the process of injection into the mold and the main molding process is performed, and this is compared with the allowable temperature pattern within the temperature comparison period, and the measured temperature is within the allowable temperature pattern. When the measured temperature reaches the solidified layer formation temperature, the injection pressure to the mold is changed and then the pressure is reduced. 8. A molded product formed by the mold when a temperature decrease gradient at the time of complete solidification of the molded product is set in advance and the measured temperature decrease slope becomes smaller than the temperature decrease slope at the time of complete solidification of the molded product. The injection molding control method according to claim 7, wherein the cooling of the above is finished.