JPH1058506A - Method for controlling power supply to nozzle heater and power supply controlling apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correspond easily and quickly to a mold, a molding resin material, etc., without replacing nozzle heaters when the mold, the molding resin material, etc., are changed, by employing a voltage regulator of a phase control system to regulate a voltage to be supplied to the nozzle heaters and performing the feedback control of power to be supplied to the nozzle heaters so that a temperature of a nozzle shows a desired level. SOLUTION: A plurality of nozzle heaters 10 provided in the longitudinal direction of a nozzle and connected in parallel to one another are connected to a power source 14 through a feeder line 12, and the nozzle is heated by closing an electromagnetic contactor 16 provided on the feeder line 12. Further, a voltage regulator 20 is provided on the feeder line 12 to set a voltage to be supplied to the nozzle heaters 10 according to the output set rate of the voltage regulator 20, and a temperature of heating the nozzle is regulated. Furthermore, a thermocouple 22 is provided to the nozzle, and, on the basis of the actually measured level of a temperature by the thermocouple 22, the closing time of the electromagnetic contactor 16 is regulated by the main body 24 of a controlling apparatus to adjust the nozzle heaters 10 and to perform the feedback control of power to be supplied thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply control method and a power supply control device for a nozzle heater that controls the power supply to a nozzle heater attached to a nozzle at the tip of a heating cylinder in an injection device to adjust the heating temperature of the nozzle.

[0002]

2. Description of the Related Art In general, a nozzle mounted at the tip of a heating cylinder of an injection device heats a molten resin to be injected to a predetermined temperature.
In order to hold the nozzle, a nozzle heater such as a band heater that generates heat when energized is attached in a state wound around the outer peripheral surface of the nozzle.

The heat capacity of a nozzle differs depending not only on the shape of the nozzle itself, but also on the size of a mold that conducts heat by touching the nozzle, and the required amount of heat also differs depending on the type of molding resin material used. . In this case, when the heat capacity or the required heat amount of the nozzle is small, heating with a nozzle heater having a large heater capacity turns ON / OFF the energization.
It becomes difficult to obtain sufficient temperature control accuracy due to large temperature fluctuations caused by turning OFF. So, conventionally,
In accordance with various molding conditions, the nozzle heater attached to the nozzle is replaced with a nozzle heater having an appropriate capacity.

[0004] However, such replacement of the nozzle heater requires a large labor burden, especially in recent years in which various types of products are manufactured in small quantities, which leads to a decrease in productivity. In addition, it is necessary to prepare a plurality of nozzle heaters for replacement. In addition, there is a problem that the nozzle heater is easily damaged at the time of replacement.

[0005]

Here, the present invention, that is, the inventions described in claims 1 to 7 are all made on the background of the above-mentioned circumstances, and particularly, the inventions described in claims 1 to 6 are provided. Can easily and quickly respond to changing the mold and the molding resin material without replacing the nozzle heater one by one, and can heat and hold the nozzle to the target temperature in an advantageous manner. An object of the present invention is to provide a method for controlling power supply to a nozzle heater.

Another object of the present invention is to provide a power supply control method for a nozzle heater which can advantageously detect a disconnection state of a nozzle heater attached to a nozzle.

According to a third aspect of the present invention, as the actual supply voltage supplied to the nozzle heater, a supply voltage having a magnitude corresponding to an output setting rate based on a voltage value externally input to the voltage regulator. It is also an object of the present invention to provide a method for controlling power supply to a nozzle heater that can obtain the following.

According to a fourth aspect of the present invention, there is provided a nozzle heater capable of obtaining, as an actual heat generation amount of a nozzle heater, a heat generation amount corresponding to an output setting rate externally input to a voltage regulator. Another object of the present invention is to provide a power supply control method.

Further, according to the present invention, even when the supply voltage to the nozzle heater is changed, the detection of the disconnection state of the nozzle heater is performed continuously and with high accuracy by a simple processing. It is another object of the present invention to provide a method for detecting a disconnection state of a nozzle heater.

Further, according to the present invention, even when a mold, a molding resin material, or the like is changed, the nozzle can be easily heated and held at the target temperature with high accuracy without replacing the nozzle heater one by one. It is an object of the present invention to provide a power supply control device for a nozzle heater capable of detecting a disconnection state of a nozzle heater attached to the nozzle in an advantageous manner.

[0011]

In order to solve the above-mentioned problem, a feature of the present invention described in claim 1 is that power is supplied to a nozzle heater attached to a nozzle attached to a tip of a heating cylinder of an injection device. In doing so, the supply voltage to the nozzle heater is adjusted using a phase control voltage regulator, the temperature of the nozzle heated by the nozzle heater is detected, and the temperature of the nozzle is determined based on the detected temperature. Is a power supply control method for a nozzle heater that performs feedback control of power supply to the nozzle heater so that the target value becomes a target value.

According to the first aspect of the present invention, the heater set is substantially changed by changing the output setting rate of the voltage regulator and adjusting the supply voltage to the nozzle heater. The same effect can be obtained. Therefore, for example, when the heat capacity of the nozzle is small, a stable temperature control can be performed by lowering the supply voltage to the nozzle heater. Therefore, it is possible to easily cope with a change in molding conditions such as a change of a mold or a molding resin material while ensuring the accuracy of controlling the temperature of the nozzle, without the need for troublesome replacement of the nozzle heater. This can advantageously reduce labor and improve productivity. The power supplied to the nozzle heater is controlled, for example, by providing a switching unit on a power supply line to the nozzle heater, and adjusting the energization time by the switching unit according to the deviation between the detected temperature of the nozzle and a target value. Can be performed advantageously.

According to a second aspect of the present invention, in the power supply control method for a nozzle heater according to the first aspect, when power is supplied to one or a plurality of the nozzle heaters, a supply current to the nozzle heater is detected. The detection current value is compared with a preset monitoring current value, and disconnection of the nozzle heater is detected when the detection current value becomes smaller than the monitoring current value.

According to the second aspect of the invention, abnormalities such as disconnection of the nozzle heater can be easily and surely prevented.
In addition, detection can be performed quickly, and occurrence of troubles due to heater disconnection or the like can be minimized. In particular, the method according to the second aspect of the present invention is advantageously applied to a case where nozzle heaters connected in parallel to each other are attached to the nozzle, and the nozzle is attached to the nozzle in such a manner. Even when a plurality of nozzle heaters are electrically connected in parallel with each other, by appropriately setting the monitoring current value, disconnection of at least one nozzle heater can be accurately detected. In this case, as the supply current to the nozzle heaters, the total value of the supply currents to the respective nozzle heaters is detected, and the monitoring current value is the supply voltage value to the nozzle heaters and one under the voltage supply state. In consideration of the amount of decrease in the current value when the nozzle heater is disconnected, the current value is set to a value that can detect that one nozzle heater is disconnected. Further, the detection of the current supplied to the nozzle heater can be performed by a current transformer (CT) or the like since a phase control type voltage regulator is employed.

According to a third aspect of the present invention, in the power supply control method for a nozzle heater according to the first or second aspect, an output setting rate based on a voltage value to the voltage regulator and an actual supply voltage to the nozzle heater are provided. Is corrected based on the output characteristics of the voltage regulator so that the output setting ratio of the voltage regulator is directly proportional, and the output of the voltage regulator is set based on the corrected output setting ratio. That is the feature.

According to the third aspect of the present invention, the actual supply voltage value to the nozzle heater is directly proportional to the output setting rate based on the voltage value of the voltage regulator set and input by the operator or the like. Will correspond.
Therefore, it is easy to recognize the relationship between the supply voltage value to the nozzle heater and the output setting rate based on the voltage value of the voltage regulator, and it is possible to grasp the supply voltage value to the nozzle heater based on the value of the output setting rate of the voltage regulator. It will be easier. This also makes it possible to easily grasp, set, change, etc. the supply voltage to the nozzle heater based on the output setting rate of the voltage regulator without using a voltmeter or the like.

According to a fourth aspect of the present invention, in the power supply control method for a nozzle heater according to the third aspect, an output setting ratio for the voltage regulator is set as a ratio of a power value. I do.

According to the method of the present invention, the amount of power supplied to the nozzle heater substantially corresponds to the amount of heat generated by the nozzle heater. If you set it as a percentage,
That value can be grasped as it is as a percentage of the calorific value of the nozzle heater. Further, since the heating value of the nozzle heater is substantially directly proportional to the heating temperature of the nozzle, the change in the output setting rate set by the voltage regulator at the ratio of the power value may be regarded as the change in the temperature of the nozzle heater. It becomes possible. Therefore, compared to the case where the output setting rate in the voltage regulator is set by the ratio of the voltage value,
This makes it easy to grasp the amount of change in the output setting rate in the voltage regulator for changing the heating temperature of the nozzle by the target value, and facilitates setting of an appropriate output setting rate in the voltage regulator.

When the output setting ratio for the voltage regulator is set as the ratio of the power value, for example, the output setting ratio: S (w) input as the ratio of the power value is calculated according to the following equation. By converting into the output setting ratio S (v) as the ratio of the voltage regulator, the voltage regulator whose output is set at the ratio of the voltage value can be used as it is. S (v) = (√S (w) / 10) × 100

The invention described in claim 5 is the same as the invention described in claim 3.
Or the power supply control method for a nozzle heater according to item 4,
When power is supplied to one or a plurality of the nozzle heaters, a supply current to the nozzle heaters (a total value of supply currents to the respective nozzle heaters when a plurality of nozzle heaters are connected in parallel with each other) is detected. The detected current value is compared with a preset monitor current value, and when the detected current value is smaller than the monitor current value, the output setting rate for the voltage regulator is detected when the disconnection of the nozzle heater is detected. When changing, the monitoring current value is changed according to the change amount of the correction output setting rate.

According to the fifth aspect of the invention, even when the output set value in the voltage regulator is changed, the supply voltage value to the nozzle heater changes in direct proportion to the output set value. Similarly, the energizing current value of the nozzle heater also changes in direct proportion to the output set value. Therefore, even when the output set value of the voltage regulator is changed, the current flowing through the nozzle heater and the monitored current value can be easily calculated by the proportional calculation without sampling the heater current each time. The monitoring current value for detecting the disconnection can be easily changed to an appropriate value.

The invention described in claim 6 is the same as the invention in claim 5
In the method of controlling the power supply of the nozzle heater according to the above, when changing the output setting rate for the voltage regulator to a small value, the monitoring current value is previously changed to a small value in accordance with the change amount of the output setting rate. That is the feature.

According to the method of the present invention, an alarm such as a buzzer or a lamp is issued when disconnection of the nozzle heater is detected due to the current supplied to the nozzle heater falling below the monitored current value. Even in such a case, there is no possibility that an alarm is erroneously issued due to a decrease in the value of the current supplied to the nozzle heater due to a change in the output setting ratio. When the output setting rate for the voltage regulator is changed to a large value, the monitoring current value may be changed after the output setting rate for the voltage regulator is changed because there is no risk of an erroneous alarm. .

Further, the invention according to claim 7 is characterized in that it is attached to a nozzle attached to the tip of the heating cylinder of the injection device.
A power supply control device for a nozzle heater for controlling power supply to one or a plurality of nozzle heaters, wherein (a) a supply voltage from a power supply to the nozzle heater can be adjusted by changing an output setting rate inputted from outside. (B) the output characteristics of the voltage regulator so that the output setting rate based on the voltage value to the voltage regulator and the actual supply voltage to the nozzle heater are in direct proportion. Output setting rate correction means for correcting the output setting rate for the voltage regulator based on the corrected output setting rate based on the obtained output setting rate, and (c) measuring the temperature of the nozzle. Temperature means, and adjusting the supply power to the nozzle heater based on the nozzle temperature measured by the temperature measurement means, thereby controlling the nozzle (D) a supply current to the nozzle heaters (when a plurality of nozzle heaters are connected in parallel with each other, a feedback means for adjusting the heating temperature to a target temperature; (E) comparing a current value detected by the current detecting means with a preset monitoring current value, and determining that the detected current value is smaller than the monitoring current value. Warning means for outputting a warning signal to
(F) When changing the output setting rate for the voltage regulator, a power supply control device for a nozzle heater comprising: monitoring current value correction means for changing the monitoring current value in accordance with the change amount of the correction output setting rate. , Features.

In the power supply control device for a nozzle heater having the structure according to the seventh aspect of the present invention, any of the invention methods according to the first, second, third and fifth aspects is advantageously implemented. The nozzle can be easily heated and maintained at the target temperature with high accuracy without changing the nozzle heater, even when changing the mold and the molding resin material, and the disconnection of the nozzle heater can be performed. An abnormal state can be advantageously detected.

In the power supply control device for a nozzle heater having the structure according to the seventh aspect of the present invention, for example, an output setting rate: S input as a ratio of the power value
Advantageously, the invention method described in claim 4 is also achieved by employing a power voltage conversion means for converting (w) into an output setting ratio: S (v) as a voltage value ratio according to the following equation. It can be implemented. S (v) = (√S (w) / 10) × 100

Further, in the power supply control device for a nozzle heater having a structure according to the invention described in claim 7, for example, when the output setting rate for the voltage regulator is changed to at least a small value, the monitoring current value is set in advance. The invention method according to claim 6 can also be advantageously implemented by adopting priority correction means of the monitoring current value that changes to a small value in accordance with the amount of change in the output setting rate. Becomes

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, in order to clarify the present invention more specifically, specific embodiments of the present invention will be described.
This will be described in detail with reference to the drawings.

First, FIG. 1 is a block diagram showing a configuration of a power supply control device of a nozzle heater for implementing the method of the present invention, which is configured according to the present invention. In this figure, reference numeral 10 denotes a nozzle heater, which is composed of a current-carrying heating element such as a band heater, and is attached to a nozzle attached to the tip of a heating cylinder of an injection device (not shown). In this specific example, at least two nozzle heaters 10 are provided. For example, the nozzle heaters 10 are attached in a state where the nozzle heaters are wound at positions separated from each other by a predetermined distance in the longitudinal direction of the nozzle (the flow direction of the resin material). I have. Further, the plurality of nozzle heaters 10 are electrically connected in parallel to each other by a power supply line 12 and are connected to a power supply 14. Then, by closing the electromagnetic contactor 16 provided on the power supply line 12, the nozzle heaters 10 are energized, and the nozzle (not shown) is heated by Joule heat. The power supply 14 may be an AC power supply or a DC power supply, but in this embodiment, an AC power supply is employed. An earth leakage breaker 18 for protecting the circuit is provided on the power supply line 12.

A voltage regulator 20 is provided on the power supply line 12.
Is installed. The supply voltage to the nozzle heater 10 is set in accordance with the output setting rate of the voltage regulator 20, so that the amount of heat generated by the nozzle heater 10 and thus the heating temperature of the nozzle are adjusted. Has become. Further, a thermocouple 22 is mounted on the nozzle at an appropriate position so that the temperature of the nozzle is measured. And thermocouple 22
Of the control device 2 based on the measured temperature value of the nozzle
4, the closing time of the electromagnetic contactor 16 is adjusted, and the amount of heat generated by the nozzle heater 10 is adjusted, so that feedback control is performed so that the temperature of the nozzle becomes the target temperature.

Further, a current measuring device (CT) 26 is provided on the power supply line 12, and a plurality of nozzle heaters 1 are provided.
The total amount of current supplied to zero is measured. Then, the disconnection of each nozzle heater 10 is monitored by the control device main body 24 based on the current value detected by the current measuring device 26.

Here, the control device main body 24 includes:
A display 38 such as an LCD, which is constituted by a computer including a CPU 28, a RAM 30, a ROM 32, and a bus 34, is connected via a display controller 36.
And various input signals such as set values and command signals are input by a keyboard 44 connected via a keyboard I / F 42. Further, a temperature detection signal of the heater by the thermocouple 22 and a current detection signal by the current measuring device 26 are inputted through the A / D converter 46, while an output setting signal in the voltage regulator 20 is converted by the D / A conversion. The switching signal of the electromagnetic contactor 16 is output through the I / O port 50 while being output through the device 48.

In the control device main body 24, the CPU 28 processes an input signal using information and the like stored in the RAM 30 according to a program stored in the ROM 32, and performs output setting and voltage control in the voltage regulator 20. In addition to opening and closing the heater 16, the disconnection of the nozzle heater 10 is determined based on the current value detected by the current measuring device 26, and the operating state and the like are displayed on the display 38.

More specifically, when controlling the current supplied to the nozzle heater 10, first, the target heating temperature T ₀ of the nozzle is determined in consideration of the type of the injection resin material, the heat capacity of the nozzle, and the like. The value is input from the keyboard 44 to the control device main body 24 and stored in the RAM 30. Also,
The output setting ratio S of the voltage regulator 20 is determined based on calculation, experience, and the like so as to obtain the desired heat generation amount of the nozzle heater 10 and the nozzle temperature, and the output setting ratio S is controlled from the keyboard 44. It is input to the device body 24. Subsequently, a heating start signal is input from the keyboard 44 to the control device main body 24, and the electromagnetic contactor 16 is closed to energize and heat the nozzle heater 10. At the same time, the thermocouple 22 causes the nozzle heating temperature:
By detecting T and inputting the detected temperature to the control device main body 24, the target heating temperature of the nozzle stored in advance:
Compared with T ₀ , the difference from the target heating temperature: δT = T ₀ −
If the value of T is δT <0, the closing time of the electromagnetic contactor 16 is shortened, and if δT> 0, the closing time of the electromagnetic contactor 16 is changed to be longer.
Feedback control is performed so that it becomes _zero . This feedback control is advantageously performed by, for example, PID control. Further, as is apparent from this, in this specific example, the feedback means is configured by a feedback control system by the control device main body 24 including the thermocouple 22 as the temperature measuring means.

Here, as the voltage regulator 20,
The phase control type is adopted for the reason of the output accuracy and the operation of the current measuring device 26. The output setting ratio S of the voltage regulator 20 is expressed as a percentage or the like as a setting ratio with respect to the maximum output voltage of the voltage regulator 20, and can be set as a voltage value or as a power value. It is possible to use the keyboard 4 in any case.
4 and the actual output voltage in the voltage regulator 20: E, that is, the supply voltage to the nozzle heater 10 is directly proportional to the output set ratio: S. The correction is applied in the control device main body 24, and the output voltage: E of the voltage regulator 20 is determined by the obtained corrected output set rate: S '. As a result, also in the phase control type voltage regulator 20, the actual output voltage E is linearly proportional to the output set ratio S.

That is, the output setting in the voltage regulator 20 generally includes a voltage signal: S corresponding to the output setting ratio: S.
v is input to the voltage regulator 20, and a voltage E corresponding to the magnitude of the voltage signal: Sv is actually supplied to the nozzle heater 10 by the voltage regulator 20, but the phase In the control type voltage regulator 20, the magnitude of this voltage signal: Sv and the actual output voltage: E
Since there is no direct proportional relationship, it is difficult to grasp the actual output voltage: E depending on the magnitude of the output setting ratio: S, and the determination of the output setting ratio: S is cumbersome and error-prone. Therefore, the voltage regulator 2
At 0, the relationship between the voltage signal: Sv and the actual output voltage: E, that is, the operation characteristics of the voltage regulator 20 is actually measured, and based on the result, the output setting ratio by voltage value: S and the voltage signal:
By correcting the relationship of Sv, the actual output voltage:
E is set to be linearly proportional to the output setting ratio S based on the voltage value.

More specifically, the output setting ratio based on the voltage value, which is obtained from the actually measured value of the operation characteristics of the voltage regulator 20, is S:
(%) And the actual output voltage: E (V) in order to make it linearly proportional, the correction amount to be added to the output set ratio: S: C
A specific example of the relationship between (%) and the voltage signal: Sv (V) input to the voltage regulator 20 based on the correction output set rate: S ′ obtained by adding the correction amount: C is as follows: This is shown in the graph of FIG. From this graph, for example,
When the output setting ratio is set to S = 50% (voltage value) so that the target output voltage is set to E = 50%, the correction value: C =
40.0%, and the voltage signal: Sv can be obtained by the following equation. Sv = 1 + (5-1) × (40/100) = 2.6 (V) The value of the output setting ratio: the correction value for S: C can also be obtained directly from the graph of FIG. Although it is possible, the output setting ratio: S = 10, 20, 30, 40, 50,
Each correction value corresponding to 60, 70, 80, 90, 100:
The value of C is stored in advance in the ROM 32 as a table, and by using the value,
Can be obtained by In this case, in order to obtain a correction value C corresponding to each numerical value of the output set ratio S stored as a table, for example, a calculation according to a linear interpolation method is advantageously employed. In this specific example, an output setting rate correction unit is configured by an operation of obtaining the correction value: C using such a graph or table and setting the voltage signal: Sv.

Then, this voltage signal: Sv = 2.6V
Is input to the voltage regulator 20, the output voltage: E of the voltage regulator 20 is determined according to the voltage signal: Sv. As a result, the output setting ratio: S = 50%
And the maximum output voltage of the voltage regulator 20 is 50
% Of the output voltage: E will be generated.
As a result, an output voltage: E having a magnitude corresponding to the magnitude of the output set rate: S is directly output from the voltage regulator 20 and supplied to the nozzle heater 10.

It is also possible to set the output setting ratio: S by a power value. In this case, for example, a given power value is converted into a voltage value, and the graph of FIG. 2 is used as it is. be able to. Specifically, for example,
When the output setting rate is S (power value) = 50%, first,
An output setting ratio as a voltage value: S, that is, a target output voltage: E is obtained by the following equation. S (voltage value) = (√50 / 10) × 100 = 70%

Thereafter, as in the case of the output setting based on the voltage value, the ROM or the graph of FIG.
, A correction value: C = 49.5% can be obtained from the data stored in the above equation, so that the voltage signal: Sv can be obtained by the following equation. Sv = 1 + (5-1) .times. (49.5 / 100) = 2.98 (V)

Then, this voltage signal: Sv = 2.98V
Is input to the voltage regulator 20, the output voltage: E of the voltage regulator 20 is determined according to the voltage signal: Sv. As a result, the output setting ratio based on the voltage value: S = 70 %, The output voltage: E having a ratio of 70% to the maximum output voltage of the voltage regulator 20 is output from the voltage regulator 20 and supplied to the nozzle heater 10.

When the output setting rate based on the power value is S, the output voltage E of the voltage regulator 20 can be expressed by the following equation. When the rate is S (%), the voltage regulator 2
0 so that the output voltage of 0 becomes E (V).
By adjusting the voltage signal Sv input to
The output voltage E by the voltage regulator 20 may be adjusted. E = Em × (√S / 10) where Em is the output voltage of the voltage regulator 20 when S is 100%: E (generally, the maximum output voltage).

As described above, when the output setting rate based on the power value is adopted, the output setting rate can be regarded as the ratio of the heating value since the power amount and the heating value agree according to Joule's law. Since the amount and the temperature are directly proportional, the change in the output set rate due to the power value can be regarded as the change in the heating temperature of the nozzle heater 10 as it is. Therefore, temperature adjustment can be performed easily, quickly, and accurately without performing complicated calculations and the like.

On the other hand, the monitoring and determination of the disconnection of the nozzle heater 10 by the control device main body 24 are performed according to, for example, the flowcharts shown in FIGS.

More specifically, first, by the operation according to the flowchart of FIG. 3, a monitoring current value: I capable of detecting that any one of the plurality of nozzle heaters 10 is disconnected.
Find ms. That is, after the start, in step Q1, an output voltage E for sampling corresponding to the output set rate S is supplied by the voltage regulator 20, and the nozzle heater 10 is energized. Note that, in this step: Q1, the operation of determining the output voltage: E corresponding to the output set rate: S is based on the operating characteristics of the voltage regulator 20, and the actual output voltage: E depends on the voltage value, as described above. Output setting rate: S
The relationship between the output setting ratio: S and the voltage signal: Sv given to the voltage regulator 20 is corrected by the correction amount: C so as to be linearly proportional to

Then, in the next step: Q2, the current measurement value Is of the power supply line 12 under the state where the output voltage: E is supplied is detected by the current measuring device 26. The contactor 16 is opened to stop energization.

Further, in step: Q4, the step for the output set rate: S in the voltage regulator 20: Q
The value of the current value: Im corresponding to the output setting ratio: S = 100% is calculated based on the relationship of the current value: Is detected in Step 2.

Thereafter, in step Q5, at least one of the nozzle heaters 10 is turned on in consideration of the current change rate when one of the nozzle heaters 10 is disconnected under the energized state of the current value: Is corresponding to the output set rate: S. A monitoring current value: Ims capable of detecting the disconnection from the amount of change in the supplied current value is obtained. The monitor current value: Ims is a current value corresponding to the output setting ratio: S = 100%: a current value corresponding to the output setting ratio: S expressed by using the value of Im: Is:
Is a preset constant: K (for example, K = 0.
7).

Such steps: By the operations of Q1 to 5,
The monitoring current value: Ims corresponding to the output setting ratio: S is obtained, and the process ends. Then, this monitoring current value: Ims is set,
By being stored, the current supplied to the nozzle heater 10 (in other words, at the time of energizing and heating the nozzle heater 10, in other words,
The current flowing through the power supply line 12): I is continuously or intermittently detected by the current measuring device 26, and is compared with the monitored current value: Ims. A warning is issued, whereby the disconnection of at least one nozzle heater 10 is detected and reported.

The initial setting of the monitoring current value: Ims may be performed when the injection device is shipped or when the nozzle heater 10 is replaced, and may be changed by changing the output setting ratio: S in the voltage regulator 20. The operation of changing the monitoring current value: Ims can be easily performed according to the flowchart of FIG.

In this operation, after the start, first, in step R1, a change value of the output set rate in the voltage regulator 20: S1 is input. Then, step: R2
The output setting ratio before change: S and the output setting ratio after change: S
If S1 <S, the operation of step: R3 is performed, and if S1> S, the operation of step: R6 is performed.

That is, if S1 <S, the steps are:
In R3, S1 is set as the output setting ratio: S, and step: R
4, the monitored current value according to the flowchart of FIG.
On the basis of the relationship between the output setting rate and the energizing current value obtained in advance in the initial setting of Ims, using a preset constant: K, under the energized state of the current value corresponding to the changed output setting rate: S Monitor current value: Ims is obtained, and the monitor current value is changed and set. Then, in step R5, the output setting ratio of the voltage regulator 20 is actually changed, and the voltage is reduced to the supply voltage corresponding to the changed output setting ratio: S, thereby completing the operation of changing the monitoring current value.

On the other hand, if S1> S, the steps are:
In R6, S1 is set as the output setting ratio: S, and the step: R
In step 7, the output set rate of the voltage regulator 20 is actually changed, and the supply voltage corresponding to the changed output set rate: S is increased. Thereafter, in step R8, a change is made using a preset constant: K based on the relationship between the output setting rate and the energizing current value obtained in advance in the initial setting of the monitoring current value: Ims according to the flowchart of FIG. Then, the monitor current value: Ims under the energized state of the current value corresponding to the output set ratio: S is obtained, and the monitor current value is changed and set, thereby completing the monitor current value change operation.

In short, when S1> S, the supply voltage may be boosted by immediately changing the output setting rate of the voltage regulator 20 immediately. However, when S1 <S, monitoring is first performed. If the current value is not changed, if the supply voltage is immediately lowered, the supply current may be smaller than the monitoring current value before the change setting, and an alarm or the like may be issued.

In the power supply control device for the nozzle heater having the above-described structure, for example, when the capacity of the nozzle heater 10 is excessive with respect to the heat capacity of the nozzle or the required heat amount of the molding resin, the output setting rate of the voltage regulator 20 is adjusted. By changing the supply voltage to the nozzle heaters, the heater capacity can be substantially reduced and stable heating temperature control of the nozzles can be performed without requiring troublesome replacement of the nozzle heaters. .

In addition, the heating temperature of the nozzle can be easily feedback-controlled by adjusting the closing time of the electromagnetic contactor 16 based on the actually measured value of the thermocouple 22. Can be easily realized.

When changing the output setting rate of the voltage regulator 20, the output setting rate based on the voltage value and the actual supply voltage value for the nozzle heater correspond to a direct proportional relationship. The operation of changing the output setting rate of the voltage regulator for obtaining the voltage value can be easily performed.

In addition, the output setting rate of the voltage regulator 20 can be set by the power value. If the output setting by the power value is adopted, the change in the setting rate is caused by the nozzle heater 10.
Since the amount of change in the heating value substantially coincides with the amount of change in the heating temperature, the amount of change in the output setting rate of the voltage regulator 20 when changing the heating temperature can be easily obtained.

When energizing the nozzle heater 10,
By comparing the energizing current value detected by the current measuring device 26 with a preset monitoring current value, the nozzle heater 1
Since the disconnection of 0 is monitored and detected, it is possible to quickly cope with the abnormality.

Further, even when the output set rate of the voltage regulator 20 is changed, the value of the output set rate based on the voltage value and the actual output voltage change in proportion to each other. Therefore, if the monitoring current value for detecting the disconnection by sampling the current value once is obtained, even if the output setting rate is changed, the appropriate monitoring current is calculated by the proportional calculation. The value can be obtained, and the change setting of the monitoring current value can be performed easily and quickly.

In addition, as described above, when the output setting rate of the voltage regulator 20 is changed, an appropriate monitoring current value can be obtained by a proportional calculation based on the energized current value sampled in advance. Compared with the conventional method of detecting the energizing current value and calculating the monitoring current value each time the output setting rate of the nozzle changes, the monitoring current value is not affected even if an abnormality occurs in the nozzle heater 10 during the operation of changing the monitoring current value. It is not affected and normal disconnection can be detected.

Although the embodiments of the present invention have been specifically described above, such specific examples are merely examples, and the present invention is not to be construed as being limited by the above specific description. Instead, the present invention can be implemented in an embodiment in which various changes, modifications, improvements, and the like are made based on the knowledge of those skilled in the art.
It goes without saying that all of them are included in the scope of the present invention unless departing from the spirit of the present invention.

[0063]

As is apparent from the above description, according to the invention method described in any one of the first to sixth aspects, even when the nozzle heat capacity changes, the output setting rate of the voltage regulator can be reduced. By changing and adjusting the supply voltage to the nozzle heater, the heater capacity can be substantially adjusted and stable nozzle heating temperature control can be performed without the need for troublesome replacement of the nozzle heater, etc. By the feedback control of the electric power supplied to the nozzle heater, the nozzle can be heated to the target temperature with high accuracy.

In the apparatus having the structure according to the seventh aspect of the present invention, even when the heat capacity of the nozzle changes, the power supply adjusts the supply voltage to the nozzle heater to thereby control the nozzle heater. The nozzle can be heated and maintained at the target temperature easily and with high accuracy without changing the heater capacity substantially without replacing each of the nozzles, and the current supplied to the nozzle heater is compared with the monitored current value. Therefore, the disconnection state of the nozzle heater can be advantageously detected.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a specific configuration example of a power supply control device for a nozzle heater according to the present invention.

FIG. 2 is a graph showing a characteristic of an output setting rate according to a voltage value and an actual output voltage in a voltage regulator, and showing a correction amount to be added to the output setting rate in order to make the output setting rate linearly proportional.

FIG. 3 is a flowchart illustrating a specific example of an operation for obtaining a monitoring current value: Ims for detecting disconnection of a nozzle heater.

FIG. 4 is a flowchart illustrating a specific example of an operation of changing a monitoring current value: Ims by changing an output setting rate in a voltage regulator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Nozzle heater 14 Power supply 16 Magnetic contactor 20 Voltage regulator 22 Thermocouple 24 Controller main body 26 Current measuring instrument

Claims (7)

[Claims] When supplying power to a nozzle heater attached to a nozzle attached to the tip of a heating cylinder of an injection device, a voltage control unit for the nozzle heater is used to adjust a supply voltage to the nozzle heater by using a phase control type voltage regulator. Detecting the temperature of the nozzle heated in the step (a), and performing feedback control of the power supplied to the nozzle heater based on the detected temperature so that the temperature of the nozzle becomes a target value. Method. 2. When power is supplied to one or more nozzle heaters, a supply current to the nozzle heaters is detected,
2. The power supply control of the nozzle heater according to claim 1, wherein the detection current value is compared with a preset monitoring current value, and the disconnection of the nozzle heater is detected when the detection current value becomes smaller than the monitoring current value. Method. 3. The voltage regulator according to the output characteristic of the voltage regulator so that an output setting ratio based on a voltage value to the voltage regulator and an actual supply voltage to the nozzle heater have a direct proportional relationship. 3. The power supply control method for a nozzle heater according to claim 1, wherein the output setting ratio for the nozzle heater is corrected, and the output setting of the voltage regulator is performed based on the obtained corrected output setting ratio. 4. An output setting ratio for the voltage regulator,
4. The power supply control method for a nozzle heater according to claim 3, wherein the method is set as a ratio of a power value. 5. When power is supplied to one or a plurality of nozzle heaters, a supply current to the nozzle heaters is detected,
The detected current value is compared with a preset monitoring current value, and when the detected current value becomes smaller than the monitored current value, the disconnection of the nozzle heater is detected. 5. The method according to claim 3, wherein when monitoring is changed, the monitoring current value is changed according to a change amount of the correction output setting rate. 6. 6. When the output setting rate for the voltage regulator is changed to a small value to lower the supply voltage to the nozzle heater, the monitor current value is set in advance according to the change amount of the output setting rate. The method according to claim 5, wherein the value is changed to a small value. 7. A power supply control device for a nozzle heater for controlling power supply to one or a plurality of nozzle heaters attached to a nozzle attached to a tip of a heating cylinder of an injection device, wherein the power supply control device controls an output setting rate inputted from outside. A voltage regulator of a phase control system capable of adjusting a supply voltage from a power supply to the nozzle heater by a change; an output setting rate based on a voltage value to the voltage regulator, and an actual supply voltage to the nozzle heater are directly proportional to Output setting ratio correction for correcting the output setting ratio for the voltage regulator based on the output characteristics of the voltage regulator so that the output setting ratio of the voltage regulator is set, based on the output characteristics of the voltage regulator. Means, a temperature measuring means for measuring the temperature of the nozzle, the nozzle based on the nozzle temperature measured by the temperature measuring means A feedback unit that adjusts a heating temperature of the nozzle to a target temperature by adjusting a power supply to the heater; a current detection unit that detects a current supplied to the nozzle heater; and the current detection unit. The detected current value is compared with a preset monitoring current value, a warning unit that outputs a warning signal when the detected current value is smaller than the monitoring current value, and an output setting ratio for the voltage regulator. A power supply control device for a nozzle heater, comprising: a monitoring current value correction unit that changes the monitoring current value in accordance with a change amount of the correction output setting rate when changing.