JPH07125035A - Vertical injection molding machine - Google Patents

Abstract

PURPOSE:To prevent the generation of unprepared response delay generated by the operation or release of a brake. CONSTITUTION:When the taking-out of a product is completed within a predetermined time t1 after the completion of the mold opening of a clamp and the mold clamping of a next molding cycle becomes possible, a brake means 31 is not operated and the mold clamping of the next molding cycle is immediately started. Therefore, so far as the taking-out of the product is normally performed, the ON/OFF control of the brake means 31 is unnecessary and a molding time is shortened as compared with a conventional product. When the taking-out of the product is not completed even if the predetermined time t1 is elapsed after the completion of the mold opening of the clamp, the excitation of a servo motor 30 is released to wait the taking-out of the product and, after the completion of the taking-out of the product, the servo motor 30 is excited to release the brake means 31 to begin next mold clamping operation. Therefore, even when the taking-out work of the product is prolonged, no excessive load is generated in the servo motor 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvement of a vertical injection molding machine.

[0002]

2. Description of the Related Art In an injection molding machine having a movable portion that moves vertically, that is, in a vertical injection molding machine, a movable platen that is a movable portion of a mold clamping mechanism, an ejector rod that is a movable portion of an ejector mechanism, and the like are used. It must be held against gravity. For this reason, in a vertical injection molding machine driven by an electric motor, a motor having a strong static torque sufficient to maintain the current position of the movable part or the current position of the movable part is canceled by canceling the action of gravity. A balancer or the like is required to hold the size, which causes problems such as an increase in size and an increase in manufacturing cost.

In order to solve such a problem, a vertical injection molding machine has been proposed in which the current position of the movable portion is held by applying a brake to the motor.
However, in the conventional vertical injection molding machine using such a mechanism, the brake is always operated to hold the current position of the movable part every time the movable part stops, so that the next position during automatic operation is Whether restarting the molding cycle or restarting the jog feed during manual operation, the brake must be released before moving the movable part before restarting, and delay in response hinders smooth operation. There was a problem that

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the drawbacks of the above-mentioned prior art, to make it compact and inexpensive, and to prevent the occurrence of an inadvertent response delay caused by the operation and release of the brake. To provide a molding machine.

[0005]

In the vertical injection molding machine of the present invention, a brake means for restraining the movement of the movable portion, a timer for starting the timing after the completion of the operation of one operation command for the movable portion, and a timer are set. Stop control means for activating the brake means to stop the supply of electric power to the electric motor unless a signal selected from the signals related to the movable part is input before timing the time, and operation to the movable part When a command is input, if the braking means is operating, the electric motor is excited and the braking means is deactivated to drive the electric motor. If the braking means is not activated, the electric motor is driven as it is. The above-mentioned object is achieved by a configuration characterized by including a drive control means for

[0006]

When the operation command is input, the drive control means determines whether or not the brake means is in operation. If the operation command is in operation, the brake means is deactivated after the electric motor is excited. To start driving. If it is not operating, the drive control means directly starts driving the electric motor. Then, when the operation of the one operation command to the movable part is completed, the timer starts time counting, and if the signal selected in relation to the movable part is not input before the timer measures the set time, the stop control means brakes. The means is actuated to restrain the movement of the movable part and stop the supply of electric power to the electric motor.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a main part of a control system of an electric vertical injection molding machine according to an embodiment. The control device for driving and controlling the vertical injection molding machine includes a CNC CPU 25 which is a numerical control microprocessor and a PMC CPU which is a programmable machine controller microprocessor.
18, to perform sampling processing of injection holding pressure and screw back pressure detected by a pressure detector (not shown) via a servo CPU 20 which is a microprocessor for servo control and an A / D converter 16. The CPU 17 for pressure monitoring is provided, and information can be transmitted between the microprocessors by selecting mutual input / output via the bus 22.

The PMC CPU 18 is connected to the ROM 13 which stores a sequence program for controlling the sequence operation of the vertical injection molding machine and the RAM 14 which is used for temporary storage of operation data. The CNC CPU 25 is connected to the vertical injection. A ROM 27 storing a program for controlling the molding machine as a whole and a RAM 28 used for temporary storage of operation data are connected.

Each of the servo CPU 20 and the pressure monitoring CPU 17 stores a ROM 21 storing a control program dedicated to servo control, a RAM 19 used for temporary storage of data, and a control program relating to a molding data sampling process. The ROM 11 and the RAM 12 used for temporary storage of data are connected. Further, the servo CPU 20 is connected to a servo amplifier 15 for driving a servo motor for each axis for ejector, mold clamping, injection, screw rotation, etc. based on a command from the CPU 20, and the servo motor for each axis is connected. Each of the outputs from the pulse coder provided in the above is fed back to the servo CPU 20, and the current position and moving speed of each axis calculated by the servo CPU 20 based on the feedback pulse from the pulse coder are stored in the current position storage register of the RAM 19 and the current speed. It is sequentially updated and stored in each of the storage registers. Among these servo motors, it is the mold clamping servo motor 30 that drives the clamp and the ejector servo motor that drives the ejector that must maintain the current position of the movable portion against gravity. Each of the motors is individually provided with braking means 31 for holding the current position of each servo motor.

The interface 23 is used to receive signals from limit switches and operation panels provided in various parts of the vertical injection molding machine and to transmit various commands to peripheral equipment of the vertical injection molding machine and braking means. I / O interface. A manual data input device 29 with a display is connected to the bus 22 via a CRT display circuit 26 so that a monitor display screen, a function menu can be selected and various data input operations can be performed. Also, various function keys and the like are provided.

The non-volatile memory 24 is a memory for storing molding data for storing molding conditions (injection pressure holding condition, measurement and kneading condition, etc.) and various set values, parameters, macro variables and the like related to injection molding work.

With the above configuration, the CNC CPU 25 distributes the pulses to the servo motors of the respective axes based on the control program of the ROM 27, and the servo CPU 20 distributes the pulse-distributed movement commands to the respective axes and the respective axes. Based on the position feedback signal and velocity feedback signal detected by a detector such as a pulse coder, servo control such as position loop control, velocity loop control and current loop control is performed in the same manner as in the past, and so-called digital servo processing is performed. Run.

2 to 3 are flowcharts showing the outline of the sequence control of one molding cycle during the automatic operation and the semi-automatic operation of the vertical injection molding machine of this embodiment, and FIG. 4 is related to the jog feed operation during the manual operation. It is a flow chart showing the outline of the processing by taking the mold clamping axis as an example, and the processing operation of the present embodiment will be described below with reference to these flow charts.

In the case of automatic operation and semi-automatic operation, the PMC CPU 18 which has detected the input of the molding start command first
A mold closing start command is output to the CNC CPU 25, and the CNC
The CPU 25 causes the servomotor 30 for mold clamping to be driven and controlled in the same manner as in the related art to perform the mold closing and mold clamping processes in the same manner as in the related art (step S1), and after the mold clamping is completed, outputs the nozzle advance command. The nozzle of the injection cylinder is touched on the die (step S2), and the CN
After the CPU 25 for C drives and controls the servo motors of the respective axes to perform the steps of injection, pressure holding, and weighing (step S3)
Up to step S5), a nozzle retreat command is output to sprue break the nozzle of the injection cylinder (step S5).
6). The processes of step S6 and step S2 related to the sprue break are performed as necessary for prevention of beating, and are not essential work requirements related to the molding work.

When the sprue break is completed (it may not be performed), the PMC CPU 18 is set to the CNC CPU 2
A mold opening start command is output to 5, and the CNC CPU 25 drives and controls the servomotor 30 for mold clamping in the same manner as in the conventional case to start the mold opening operation (step S7).
The current position of the clamp is sequentially read from M19, and the process waits until the clamp position reaches the mold opening completion position (steps S8 to S9).

When pulse distribution by the CNC CPU 25 is completed and it is confirmed that the clamp position has reached the mold opening completion position, the PMC CPU 18 outputs a product removal command to the product removal robot via the interface 23. (Step S10), the timer is set to t1.
Is set to start timing (step S11). The set value t1 is an excitation allowable time for waiting for product extraction in a state where the mold clamping servo motor 30 is excited, and is a range in which a problem such as burnout does not occur in the mold clamping servo motor 30,
It is a value arbitrarily set according to the work required time of the product take-out robot and the like (set and stored in the non-volatile memory 24).

Thereafter, the PMC CPU 18 repeatedly executes a determination process of whether or not a take-out completion signal from the product take-out robot is input (step S12) and whether or not the timer has finished counting (step S13). And wait for the product to be taken out. That is, the take-out completion signal from the product take-out robot is a signal selected from the signals related to the clamp which is the movable part, and in short, whether or not to permit the start of the mold closing operation of the clamp in the next molding cycle. It is a signal to decide whether.

If a take-out completion signal from the product take-out robot is detected (step S12 is true) before the timer finishes counting, and it is confirmed that the normal product take-out work is performed, the PMC CPU 18 Further determines whether or not the automatic operation should be ended (step S14). If it is not necessary to end the automatic operation, the process proceeds to step S1 again and the next step is performed in the same manner as described above. The sequence control of the molding cycle will be started.
In this case, the brake means 31 of the mold clamping shaft does not operate.

On the other hand, when it is necessary to end the automatic operation, for example, the semi-automatic operation is defined by operating the semi-automatic operation switch and closing the safety door, and then the aforementioned sequence is started, during which the automatic operation switch is operated. If it does not exist (in the case of semi-automatic operation), or if the semi-automatic operation switch is operated during execution of automatic operation to define the end of automatic operation (end of automatic operation by manual operation), or in the shot number counter When the production of the preset target shot number is completed, etc., step S1
The determination result of 4 is true. In such a case, there is no plan to start the next molding cycle immediately, so PM
The C CPU 18 operates the braking means 31 provided in the mold clamping servomotor 30 to prevent the clamp from dropping due to its own weight (step S21), and releases the excitation of the servomotor 30 to prevent accidents such as motor burnout. This is prevented (step S22).

When the time counting by the timer is completed without detecting the take-out completion signal from the product taking-out robot (step S13 is true), the taking-out of the product is difficult and the retry operation of the product taking-out robot is repeated. Since the next molding cycle cannot be immediately started, if the servomotor 30 of the mold clamping shaft is continuously excited as it is, an accident such as heating or burning of the motor may occur. Therefore, in such a case, the PMC CPU 1
8 is a brake means 31 of the servomotor 30 of the mold clamping shaft.
Is operated to prevent the clamp from falling due to its own weight (step S15), the excitation of the servomotor 30 is released (step S16), and the standby state is again waited for the product to be taken out (step S17).

When the take-out completion signal from the product take-out robot is detected and the completion of the product take-out operation is confirmed (step S17 is true), the PMC CPU 18
Further, similarly to the above, it is determined whether or not the automatic operation should be ended (step S18), and if it is not necessary to end the automatic operation, the servo motor 30 for mold clamping is excited again to operate the braking means. After returning to the previous state (step S19), the operation of the braking means 31 of the mold clamping servomotor 30 is released (step S20), the process proceeds to step S1 again, and the same sequence control as described above is performed. Will be started. If it is necessary to end the automatic operation (step S18 is true), the operation is ended in the mold open state while the brake means 31 of the mold clamping servomotor 30 is activated. The braking means 31 actuated at this point of time causes the mold clamping servomotor 30 to be operated before the next semi-automatic operation (automatic operation is started by operating the automatic operation key during the semi-automatic operation). Is excited and released in advance.

As described above, a short time (set value t
When the product is taken out in 1) and the mold closing operation in the next molding cycle becomes possible, the brake means 31 is not operated and the clamp is moved to the mold opening completion position by the torque of the mold clamping servomotor 30. As compared with the conventional product in which the braking means 31 is always operated every time the operation is completed, the molding time is equal to the required time required to operate and deactivate the braking means 31 in each molding cycle. Will be shortened. Further, when it is necessary to hold the clamp at the mold opening completion position for a long period of time that may adversely affect the servo motor 30, while the safety of the servo motor 30 is ensured, Since the brake means 31 is automatically operated to hold the clamp at the mold opening completion position and the excitation to the servo motor 30 is released, accidents such as burning or heating of the servo motor 30 are prevented in advance.

On the other hand, the jog feed relating to the mounting operation of the mold and the preparatory operation for setting the mold opening completion position is performed according to the process of the manual operation mode as shown in FIG. Note that FIG. 4 shows an outline of processing that is started when the clamp shaft is selected by the drive shaft selection key after the manual operation switch is operated. , Ejector shaft, injection unit moving shaft, etc.

The PMC CPU 18, which has detected the operation of the manual operation switch and the clamp axis selection key, first starts the semi-automatic operation switch (the automatic operation mode is started by operating the automatic operation switch during the semi-automatic operation. It is not possible to directly start the automatic operation) and whether or not the drive axis selection key of another moving axis is operated (step T1). If the key has not been operated, it is further determined whether or not the axis movement key has been operated (step T2). If the axis movement key has not been operated, the determination processing of steps T1 and T2 is repeatedly executed. And wait as it is.

The axis movement key itself is commonly used for the clamp axis, the screw axis, the ejector axis, the injection unit movement axis, etc., and which axis is moved by operating the axis movement key. It is restricted according to the operating state of the drive axis selection key. There are two types of axis movement keys, one for instructing clamp movement in the mold opening direction and the other for instructing clamp movement in the mold closing direction (when the screw shaft is selected. Then the injection direction −
Corresponding to the direction of reflection / ejection, when the ejector axis is selected, it corresponds to the projecting direction-retracting direction, and when the injection unit moving axis is selected, it corresponds to the nozzle touch direction-sprue break direction). Even when a key is operated, the processing content itself by the PMC CPU 18 is the same, and the directions of movement instructed by the movement command are simply different. Therefore, in the following description, the movement direction of the axis will be described. The description is omitted. Needless to say, the clamp moves in the mold opening direction when the axis moving key in the mold opening direction is operated, and the clamp moves in the mold closing direction when the axis moving key in the mold closing direction is operated. Of. The axis movement keys in this embodiment are normally open automatic return type push switches.

Therefore, the PMC CPU 18 executes the step T.
When the operator presses the axis movement key while repeatedly executing the determination processing of 1 and step T2, the PMC CPU 18 that detects this operation first excites the servomotor 30 of the mold clamping axis to determine the current position of the clamp. It is held (step T3), the brake means 31 of the clamp shaft is released (step T4), a clamp movement command is output to the CPU 25 for CNC to distribute a predetermined amount of pulse, and the servo motor 30 of the mold clamping shaft is driven. To move the clamp by the movement amount of one operation command (step T5).

Next, the PMC CPU 18 determines whether the axis movement key is OFF, that is, whether the operator has released the depression of the axis movement key (step T6), and the axis movement key is turned off. If it is not OFF, the processes of steps T5 and T6 are repeatedly executed in the same manner as described above, and the clamp is moved at a low speed by one movement command until the operator releases the axis movement key. . This movement is substantially continuous.

When the operator releases the axis movement key, the PMC CPU 18 detects this operation in the discrimination processing of step T6, sets the set value t2 in the timer, and starts time measurement (step T7). A standby state is awaited for the completion of time counting by the timer or the pressing operation of the axis movement key again (steps T8 and T9).

Here, if the axis movement key is pressed again before the timer is completed and the result of the determination in step T9 becomes true, the PMC CPU 18 shifts to the processing in step T5, and in the same manner as described above. The processes of steps T5 and T6 are repeatedly executed, and the clamp is continuously moved at low speed by the movement amount of one operation command until the operator releases the axis movement key. For example, after mounting the mold,
This is the operation of the axis move key to detect the appropriate mold opening completion position by moving the clamp in small steps in the preparatory operation for setting the mold opening completion position.
The operation of the axis movement key is not interrupted for a long time.

When the timer is completed without re-operating the axis movement key, the PMC CPU 18 operates the brake means 31 provided in the mold clamping servomotor 30 to prevent the clamp from dropping due to its own weight. After releasing the excitation of the servo motor 30 (step T10, step T11), the process proceeds to step T1 to operate the semi-automatic operation switch or the drive axis selection key of another moving axis, or the current selection. It will return to the initial standby state waiting for the operation of the axis movement key for the axis that is currently in operation. For example, the pressing release operation when the clamp is fully opened for inserting the mold corresponds to this, and in such a case, a relatively long time is required for inserting and mounting the mold. However, the operation is completed before the next operation of the next axis movement key.

As in the case of automatic operation and semi-automatic operation,
When it is necessary to move the clamp frequently within a short time, the brake means 31 is not operated and the clamp is held at the current position by the torque of the mold clamping servomotor 30, so that 1 Compared with the conventional product in which the brake means 31 is always operated every time the operation command is completed,
The manual feed of the clamp can be performed more smoothly, and in the case where the axis movement key is released for a long time, the braking means is automatically operated while the safety of the servo motor 30 is ensured. Since the actuator 31 is operated to hold the clamp at the current position and the excitation of the servo motor 31 is released, accidents such as burning or heating of the servo motor 30 can be prevented.

Then, the operator who has completed the required manual operation operation moves the clamp to the mold opening completion position and moves the screw to the measurement completion position by manual operation,
If you operate the semi-automatic operation switch and close the safety door,
This operation is detected in the determination processing of step T1, and the PMC
The CPU 18 starts the sequence control as shown in FIGS. 2 and 3. The process when the drive axis selection key of another moving axis is operated, for example, when the selection key of the ejector axis affected by gravity is operated, is substantially the same as that shown in FIG. Of course, the servo motor to be driven is different from the brake means), but for an axis that moves only in a direction irrelevant to the action of gravity, ON / OFF control of the brake means or excitation / de-excitation control of the servo motor is not always necessary. is not.

[0033]

According to the vertical injection molding machine of the present invention, when the same moving part is required to be moved within a predetermined time after completion of the operation of one operation command for the vertically moving moving part, the electric injection molding machine is electrically operated. While holding the current position of the moving part by the motor,
When it is not necessary to move the same movable portion even if a predetermined time has elapsed after the completion of the operation of one operation command, the movable portion is held at the current position by the brake means that restrains the movement of the movable portion, and the electric motor Since the supply of electric power is stopped, the ON / OFF control of the brake means becomes unnecessary when the movable part is moved frequently, and the drive control with excellent responsiveness can be performed. Even if it is necessary to maintain the current position of the movable portion for a long time, the electric motor will not be overloaded, and a large motor or balancer is unnecessary. Further, the motor can be downsized as compared with the case where the motor is not demagnetized, so that the cost can be cut. Since the clock timer is provided before the brake is operated, the cycle time can be shortened by performing the next cycle before the timer is completed.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main part of a control system of an electric vertical injection molding machine according to an embodiment of the present invention.

FIG. 2 is a flowchart showing an outline of sequence control of one molding cycle during automatic operation and semi-automatic operation of the vertical injection molding machine of the embodiment.

FIG. 3 is a continuation of a flowchart showing an outline of sequence control of one molding cycle during automatic operation and semi-automatic operation.

FIG. 4 is a flowchart showing an outline of processing regarding a jog feed operation during manual operation of the vertical injection molding machine of the embodiment.

[Explanation of symbols]

 15 Servo Amplifier 18 CPU for PMC 20 Servo CPU 22 Bus 23 Interface 24 Nonvolatile Memory 25 CPU for CNC 30 Servo Motor for Clamping 31 Braking Means

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B29C 45/66 7365-4F

Claims (3)

[Claims] 1. A vertical injection molding machine in which a vertically moving movable portion is driven by an electric motor, and a braking means for restraining the movement of the movable portion, and a timing start after the completion of one operation command for the movable portion. And a stop for activating the brake means to stop the supply of electric power to the electric motor unless a signal selected from the signals related to the movable portion is input before the timer measures a set time. When the control means and the operation command to the movable portion are input, if the brake means is in operation, the electric motor is excited and the brake means is deactivated to drive the electric motor. A vertical injection molding machine comprising: drive control means for driving the electric motor as it is if the brake means is inoperative. 2. The movable part is a mold clamping mechanism.
Vertical injection molding machine described. 3. The vertical injection molding machine according to claim 1, wherein the movable portion is an ejector mechanism.