JP2002248665A - Method and device for controlling injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for controlling an injection molding machine in which the maintenance of a mold is done at an appropriate point of time and a device for the method. SOLUTION: Standard torque and limit torque are set based on driving torque necessary for a mold closing operation (S501 and S502). After that, the driving torque is measured every time of the mold closing operation and compared with the standard torque and the limit torque (S503 and S504). When the measured driving torque is deviated from the range between the standard torque and the limit torque, it is judged that mold clamping is done abnormally, and the number of times of the abnormality is counted (S505). When the number of the counted values reaches N, an alarm is raised to promote the maintenance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding machine and, more particularly, to a control method and a control device therefor.

[0002]

2. Description of the Related Art In an injection molding machine, when the injection molding operation is repeated, galling occurs on a positioning guide pin or a slide mold formed on a mold, resulting in poor movement (astringency). There is.

Therefore, conventionally, an operator observes the movement of the mold, and when the operator feels abnormal, inspects, repairs, or replaces the mold.

[0004]

Conventionally, since the operator observes the movement of the mold and detects the abnormality, the mold is frequently inspected more than necessary. On the contrary, there is a problem that maintenance may not be performed at all.

[0005] In order to solve such a problem, a method of performing a periodic inspection such as a pre-operation inspection is conceivable. However, it still depends on the judgment of the operator. There is a possibility that maintenance will not be performed.

Accordingly, an object of the present invention is to provide a control method and a control apparatus for an injection molding machine that enable maintenance of a mold at an appropriate time or cycle.

[0007]

According to the present invention, in a method for controlling an injection molding machine, a first step of judging whether or not a mold closing operation has been normally performed, and a step of determining whether or not the mold closing operation has been performed in the first step. A second step of counting the number of times that the closing operation is determined to have been performed abnormally, and a third step of issuing an alarm prompting maintenance when the value counted in the second step matches a preset value. Steps and
And a control method for an injection molding machine characterized by including the following.

More specifically, in the control method of the present invention,
In the first step, a reference torque larger than a driving torque of a mold closing operation in a state where the injection molding machine is operating normally and a limit torque larger than the reference torque are determined in advance, and the injection molding is performed. The driving torque during the mold closing operation is measured while repeating the operation, and when the measured driving torque is equal to or more than the reference torque and equal to or less than the limit torque, it is determined that the mold closing operation is abnormally performed.

Alternatively, in the first step,
A reference time longer than the time of the mold closing operation in a state where the injection molding machine is operating normally, and a limit time longer than the reference time are determined in advance, and the injection closing operation is repeated to perform the mold closing operation. The required time is measured, and when the measured time is equal to or longer than the reference time and equal to or shorter than the limit time, it is determined that the mold closing operation is abnormally performed.

Further, according to the present invention, in the control device of the injection molding machine, a judging unit for judging whether or not the mold closing operation has been normally performed, and a judgment that the mold closing operation has been abnormally performed in the judging unit. A control of an injection molding machine, comprising: a counter for counting the number of times determined; and an alarm unit for issuing an alarm for urging maintenance when a value counted by the counter matches a preset value. A device is obtained.

More specifically, in the control device according to the present invention, the determining unit determines a reference torque larger than a driving torque of a mold closing operation in a state where the injection molding machine is operating normally and a reference torque based on the reference torque. A setting unit that presets a large limit torque, a measuring unit that measures the driving torque during the mold closing operation while repeating the injection molding operation, and the driving torque measured by the measuring unit, the reference torque, and the limit torque. And a comparison unit for comparing, based on a comparison result of the comparison unit, when the measured drive torque is equal to or more than the reference torque and equal to or less than the limit torque, the mold closing operation is abnormally performed. to decide.

Alternatively, the determining unit may include a setting unit that presets a reference time longer than a time of a mold closing operation in a state where the injection molding machine is operating normally and a limit time longer than the reference time. A measuring unit for measuring the time required for the mold closing operation while repeating the injection molding operation, and a comparing unit for comparing the time measured by the measuring unit with the reference time and the limit torque, the comparing unit If the measured time is equal to or longer than the reference time and equal to or shorter than the limit time, it is determined that the mold closing operation has been abnormally performed.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings.

First, an injection molding machine to which the present invention is applied will be described with reference to FIG. The injection molding machine in FIG. 1 plasticizes the raw material and uses the plasticized raw material in a pair of molds 11 and 1.
A plasticizing device (or injection device) 13 for injecting into a cavity formed by the mold 2 and a pair of molds 1
A mold clamping mechanism 14 for fixing one of the members 1 and 12 and moving the other to perform a mold clamping operation (mold closing / mold opening operation).

One mold (cavity mold) 12 is
It is fixed to the fixed platen 15 of the mold clamping mechanism. The other mold (core-side mold) 11 is fixed to the movable platen 16. A toggle link 17 is connected to the movable platen 16, and the toggle link 17 is driven by a drive motor (not shown). The principle of movement of the core-side mold 11 using the toggle link 17 is as shown in FIGS. That is, FIG. 2A shows a mold open state, in which the toggle link 17 is in a bent state. By gradually extending the toggle link 17 straight from this state, the movable platen 16 moves toward the fixed platen 15 as shown in FIG. When pressed against the mold 12, the mold is closed as shown in FIG.

FIG. 3 shows an example of the core-side mold 11. FIG.
As shown in (1), a plurality of guide pins 31 and a plurality of thrust receivers 32 are formed on a surface of the core-side mold 11 facing the cavity-side mold 12. In order to correspond to the guide pins 31 and the thrust receiver 32, the cavity mold 12 is formed with a concave portion for receiving them on a surface facing the core mold 11. The core-side mold 11 is provided with an eject pin 33 whose tip is directed toward a surface facing the cavity mold 12 so as to be able to be taken in and out.

Next, a control device of the injection molding machine according to the present invention will be described with reference to FIGS.

As shown in FIG. 4, the control device according to the present embodiment comprises an input / output unit 41, an operation control unit 42, a measuring unit 4
3, a setting unit 44, a comparison unit 45, and a counter 46.

The input / output unit 41 is for the operator to input data and the like necessary for the operation of the control device.
The input / output unit 41 also operates as an alarm unit that issues an alarm for urging maintenance.

The operation control unit 42 controls the operation of the injection molding machine based on data such as parameters given from the input / output unit 41.

The measuring section 43 measures a driving torque of a driving motor for driving the toggle link 17 to perform a mold closing operation of the injection molding machine. (Before the operation, the driving torque of the normal mold closing operation is measured, and then the driving torque during the operation is measured.) The setting unit 44 uses the driving torque measured by the measuring unit 43 to set the reference torque and the driving torque. Calculate and store the limit torque.

After the setting unit 44 obtains and stores the reference torque and the limit torque, the comparison unit 45 compares the result measured by the measuring unit 43 with the reference torque and the limit torque stored by the setting unit 44, and determines whether the type is normal. It is determined whether or not the closing operation has been performed (whether the mold clamping operation has been performed abnormally).

The counter 46 counts the number of times that the comparing section 45 determines that the mold closing operation has been performed abnormally.

The actual control device can be realized by a computer such as a personal computer or an information processing device and a computer program.

Next, the operation of the control device of FIG. 4 will be described with reference to FIG.

First, the operator gives necessary information to the input / output unit 41. The necessary information includes information for determining whether to continue the injection molding operation or to temporarily stop the operation when an alarm for urging mold maintenance is generated after the start of the injection molding operation. When necessary information is not input, the input / output unit 41 requests the operator to input necessary information.

The operation control section 42 controls the injection molding machine to execute the injection molding operation based on the information supplied from the input / output section 41.

The measuring section 43 measures a driving torque of a driving motor for driving the toggle link 17 when the injection molding machine performs a mold closing operation. Then, the measurement unit 43 performs step S5
At 01, it is determined whether or not the reference torque is stored in an internal memory (not shown). If the reference torque is not stored in the internal memory, the measuring unit 43 proceeds to Step S502
In, a reference torque is determined based on the measured drive torque (necessary drive torque) and stored in an internal memory. At the same time, the measuring unit 43 determines a limit torque that is larger than the reference torque by a predetermined value and stores the limit torque in the internal memory. The reference torque is a value smaller than the abnormal drive torque, and is set so that the drive torque measured during the subsequent mold closing operation does not exceed the value as long as the injection molding is performed normally. . This means that the reference torque is larger than the drive torque during normal operation. The limit torque is for detecting a state that is particularly problematic among states called abnormalities, such as when a molded product is sandwiched between molds.

The measuring section 43 notifies the comparing section 45 of the measured driving torque. The comparison unit 45 determines in step S
In 503, the driving torque measured by the measuring unit 43 is compared with the reference torque stored in the setting unit 44. As a result of the comparison, if the measured drive torque is lower than the reference torque, it is determined that a normal mold closing operation is being performed, and nothing is performed. On the other hand, if the measured drive torque is equal to or greater than the reference torque, the comparing unit 45 proceeds to step S504.
, The measured drive torque is compared with the limit torque stored in the setting unit 44. As a result of the comparison, if the measured drive torque is equal to or less than the limit torque,
The comparing unit 45 notifies the counter 46 of the fact.
That is, the comparing unit 45 notifies the counter 46 that an abnormal mold closing operation has been performed. On the other hand, when the measured drive torque exceeds the limit torque, the comparison unit 45 notifies the operation control unit 42 of the fact. That is, the comparison unit 45
Notifies the operation control unit 42 that an abnormality such as a molded product is sandwiched between the molds has occurred.

When the counter 46 receives the notification from the comparing section 45 that the mold closing operation has been performed abnormally, the counter 46 proceeds to step S.
At 505, the count value is incremented by one. Then, in step S506, the counter 46 compares the count value with a preset set value N. If the count value is smaller than N, the counter 46 does nothing. On the other hand, when the count value becomes N or more, the counter 46 notifies the input / output unit 41 of the fact.

When the input / output unit 41 receives a notification from the counter 46 that the count value has become N or more, it issues an alarm for urging the maintenance of the mold in step S507. In addition, if it is set in advance that the injection molding operation should be stopped when an alarm occurs, the input / output unit 41 requests the operation control unit 42 to stop the operation.
If it is not set in advance to stop the injection molding operation when an alarm is generated, the input / output unit 41 continues to issue an alarm until an operator performs an operation, and does nothing to the operation control unit 42.

In step S508, the operation control unit 42 notified from the comparison unit 45 that the measured drive torque exceeds the limit torque stops the injection molding operation immediately in order to prevent the mold from being damaged. Then, a mold protection operation is performed.

As described above, according to the control device according to the present embodiment, if the abnormal mold closing operation is performed N times a preset number of times, an alarm prompting maintenance is issued. Mold maintenance can be performed at an appropriate period.

In the above-described embodiment, the drive torque of the drive motor for driving the toggle link 17 is measured, and is used to determine whether or not the normal mold closing operation is performed. The time required to perform a normal mold closing operation is measured, and the reference time and the limit time at which the reference torque and the limit torque are changed to the reference torque and the limit torque are obtained. And the limit torque may be compared to determine whether a normal mold closing operation is being performed. In this case, the reference time is set to be longer than the time of the normal mold closing operation, and the limit time is set to be longer than the reference time by a predetermined time.

In the above-described embodiment, the reference torque and the limit torque are obtained from the drive torque necessary for the mold closing operation immediately after the start of the injection molding operation. The reference torque and the limit torque may be obtained using the average value of the driving torque.

Further, in the above embodiment, the reference torque and the limit torque are obtained only when the reference torque is not set. However, the reference torque and the limit torque are updated periodically (for example, every hour). You may make it.

[0037]

According to the present invention, an alarm for urging maintenance is issued after the abnormal mold closing operation is repeated a set number of times, so that an appropriate time can be obtained without depending on the judgment of the operator. The mold can be maintained (periodically).

Further, by determining whether or not the mold closing operation has been performed normally, the positioning guide pins and the slide mold are entangled, and the molded product is sandwiched between the molds. When an abnormality occurs, the injection molding operation can be stopped.

[Brief description of the drawings]

FIG. 1 is a schematic view of an injection molding machine to which the present invention is applied.

FIGS. 2A and 2B are schematic diagrams for explaining the principle of driving a movable platen by a toggle link in the injection molding machine of FIG. 1, wherein FIG. 2A is a mold open state, FIG. 2B is an intermediate state, and FIG.
FIG. 4 is a view showing a mold closed state.

FIG. 3 is a perspective view showing an example of a core-side mold.

FIG. 4 is a block diagram of a control device according to one embodiment of the present invention.

FIG. 5 is a flowchart for explaining the operation of the control device in FIG. 4;

[Explanation of symbols]

 Reference Signs List 11 core-side mold 12 cavity-side mold 13 plasticizing device 14 mold clamping device 15 fixed platen 16 movable platen 17 toggle link 31 guide pin 32 thrust receiver 33 eject pin 41 input / output unit 42 operation control unit 43 measuring unit 44 setting unit 45 Comparison section 46 Counter

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F202 AM09 AP04 AP10 AP18 AR04 AR11 AR19 CA11 CL01 CS07 4F206 AM09 AP04 AP10 AP18 AR04 AR11 AR19 JA07 JM02 JN31 JP05 JP15 JQ83

Claims (10)

[Claims] 1. A method for controlling an injection molding machine, comprising: a first step of determining whether or not a mold closing operation has been normally performed; and determining that the mold closing operation has been abnormally performed in the first step. A second step of counting the number of times the vehicle has been operated, and a third step of issuing an alarm prompting maintenance when the value counted in the second step matches a preset value. Control method of injection molding machine. 2. In the first step, a reference torque larger than a driving torque of a mold closing operation in a state where the injection molding machine is operating normally and a limit torque larger than the reference torque are determined in advance. In addition, the drive torque during the mold closing operation is measured while repeating the injection molding operation, and if the measured drive torque is equal to or more than the reference torque and equal to or less than the limit torque, the mold closing operation is abnormally performed. 2. The control method for an injection molding machine according to claim 1, wherein it is determined that the injection molding machine has failed. 3. In the first step, a reference time longer than a time of a mold closing operation in a state where the injection molding machine is operating normally and a limit time longer than the reference time are determined in advance. Each time, the time required for the mold closing operation is measured while repeating the injection molding operation, and if the measured time is equal to or longer than the reference time and equal to or shorter than the limit time, it is determined that the mold closing operation is abnormally performed. 2. The control method for an injection molding machine according to claim 1, wherein: 4. A fourth step of receiving an input for selecting whether to continue or stop the injection molding operation of the injection molding machine if the value counted in the second step matches the set value. 4. The control method for an injection molding machine according to claim 1, wherein the control method includes: 5. The operation of the injection molding machine is stopped when the measured driving torque exceeds the limit torque or when the measured time exceeds the limit time in the first step. 4. The control method for an injection molding machine according to claim 2, further comprising a fifth step. 6. A control unit for an injection molding machine, wherein a determining unit for determining whether or not the mold closing operation has been performed normally, and counting the number of times the determining unit determines that the mold closing operation has been performed abnormally. A control device for an injection molding machine, comprising: a counter for performing a maintenance operation when a value counted by the counter matches a preset value. 7. The setting unit determines in advance a reference torque larger than a driving torque of a mold closing operation in a state where the injection molding machine is operating normally and a limit torque larger than the reference driving torque. A measuring unit that measures a driving torque during a mold closing operation while repeating an injection molding operation; and a comparing unit that compares the driving torque measured by the measuring unit with the reference torque and the limit torque. Based on a comparison result of the comparison unit, when the measured drive torque is equal to or more than the reference torque and equal to or less than the limit torque, it is determined that the mold closing operation is abnormally performed. The control device for an injection molding machine according to claim 6. 8. A setting unit for setting a reference time longer than a time of a mold closing operation in a state where the injection molding machine is operating normally and a limit time longer than the reference time. A measuring unit that measures the time required for the mold closing operation while repeating the injection molding operation; and a comparing unit that compares the time measured by the measuring unit with the reference time and the limit torque. 7. When the measured time is equal to or longer than the reference time and equal to or shorter than the limit time, based on the comparison result, it is determined that the mold closing operation has been abnormally performed. Control device for injection molding machine. 9. An input for receiving a selection input for continuing or stopping the injection molding operation of the injection molding machine when the value counted by the counter matches the set value. 6. The device according to claim 6, wherein
Or the control device of the injection molding machine of 8. 10. An operation stopping unit for stopping the operation of the injection molding machine when the torque measured by the determination unit exceeds the limit torque or when the measured time exceeds the limit time. The control device for an injection molding machine according to claim 7 or 8, wherein: