JPH04135821A - Sprue ejecting device - Google Patents

Abstract

PURPOSE:To automatically remove the retention of a sprue runner by a method wherein a sensor to detect the retention of the sprue runner is provided so as to stop molding work and to insert the tip of a rod member from the rear surface of a fixed platen into the sprue bushing of a mold upon the receipt of a retention detection signal in order to push down the sprue runner outside the mold. CONSTITUTION:A camera 23 detects the retention of a sprue runner in comparison with a reference printed image and outputs a retention detection signal to the controlling device of an injection molder. A CPU outputs injection unit retreating command so as to retreat an injection unit 6 to the direction, by which an injection unit 6 is separated from a fixed platen 2. Next, a cylinder extension command is outputted to a cylinder driving circuit so as to drive an air cylinder 18 in order to clockwise rock a rocking arm 17, which consists of some part of a first driving means, resulting in positioning a rod member 19 on the injection axis. Further, a driving command is outputted to a vibrator driving circuit so as to drive a vibrator 20 in order to axially vibrate the rod member 19. Furthermore, a direct driving mechanism advancing command is outputted so as to drive a direct driving mechanism 21, which is composed of the first and a second driving means, in order to advance the rod member 19 along the injection axis to the direction approaching to the fixed platen 2.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a sprue ejection device that automatically removes runners remaining on a sprue bush of a mold.

Conventional technology Molds equipped with ejector turbines and stripper plates on the movable side mold are provided with reverse tapered undercuts drilled in the runner groove of the movable side mold, and in accordance with the sprue position of the stationary side mold. The runner formed in the injection molding process is held in the movable mold by the runner lock pin, etc., and the mold is opened, and the ejector turbine and stripper plate of the movable mold are operated during or after the mold opening is completed. For molds equipped with a stripper plate on the fixed side mold, the runner is released by moving the stripper plate in the mold opening direction in conjunction with the mold opening operation. .

Runners formed in the injection molding process include runner grooves carved in the parting line of the mold, and runners formed by resin paths inside the sprue bushing of the stationary mold. The resin path inside the sprue bush is composed of a tapered through hole whose diameter decreases from the parting line of the stationary mold toward the holding plate. ), but if the tapered surface is insufficiently polished or the nozzle diameter of the injection molding machine and the inner diameter of the sprue bushing do not match, the sprue runner may become attached to the inner periphery of the resin path. It firmly adheres to the surface, making it difficult to release the sprue runner from the mold.

Also, if the design of the undercut or runner lock pin of the movable side mold is inappropriate, or if these parts wear out due to long-term use, or if the molding conditions have been changed. , often the sprue runner remains in the sprue bush.

If a product or runner is caught between the molds, the injection molding machine detects the change in mold thickness and activates the mold protection mechanism to stop the molding operation, but the sprue runner is ripped off from the other runners and the sprue is damaged.・If it remains in the mold, it is difficult to detect it, and if you move on to the next injection molding process, the sprue runner will not only restrict the flow of resin, resulting in molding defects, but in some cases, overfilling may cause the resin to leak. This is extremely dangerous as the sprue runner may flow back or blow out, and it is desirable to detect any remaining sprue runner and stop the molding operation before proceeding to the next injection molding process.

If sprue runner remains, open the injection molding machine, heat a wire with a bent tip using the flame of a lighter or burner, and use the tip to melt the sprue runner and mold it. Insert into the resin path in the sprue bush from the parting line side of the mold,
Once the wire has cooled down, pull out the wire and take out the sprue runner along with the wire, or move the injection unit back, insert a copper rod into the resin path of the sprue bushing from the fixed platen side, and hit it with a resin hammer. I tried to push out the sprue runner, but it was inefficient and troublesome.

Problems to be Solved by the Invention The present invention has been made in view of these problems.
It is an object of the present invention to provide a sprue ejection device that detects residual sprue runners and automatically eliminates the residual sprue runners.

Means for Solving the Problem A sensor is provided to monitor a mold mounted on a fixed platen of an injection molding machine and detect residual sprue runner when the mold is opened, and a control means receives a residual detection signal from the sensor. An interlock is applied to the molding operation of an injection molding machine to stop the molding operation.

After stopping the molding operation with the mold open, the injection unit is moved back and the first injection unit is opened. The second driving means is actuated to move the tip of the rod member, which is in the original position spaced apart from the injection shaft in the radial direction of the injection shaft on the back side of the fixed platen, to the nozzle touch position of the injection molding machine, and then to the injection shaft. The tip of the rod member is inserted into the sprue bush of the mold from the back side of the fixed platen, and the sprue runner is pushed out of the mold.

Next, the second. The first driving means is operated to retract the rod member from the injection shaft to the original position, and an injection unit advance command is output to release the interlock of the injection molding machine, making it possible to restart the molding operation.

The control means receives the residual detection signal from the sensor that monitors the mold mounted on the fixed platen, interlocks the molding operation of the injection molding machine to stop the molding operation, and outputs an injection unit retreat command. After retracting the injection unit, the first drive means is actuated to move the tip of the rod member to the nozzle touch position of the injection molding machine, and the second drive means is actuated to move the rod member along the injection axis. By moving the rod member, the tip of the rod member is inserted into the sprue bush of the mold from the back side of the fixed platen, and the sprue runner remaining in the sprue bush is pushed out of the mold.

The control means then operated the second drive means to return the tip of the rod member to the nozzle touch position of the injection molding machine, and operated the first drive means to return the rod member to its original position. After that, the injection unit advance command is issued to release the interlock of the injection molding machine and restart the molding operation.

Example Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a side view showing the main parts of an electric injection molding machine according to an embodiment to which the sprue ejecting device of the present invention is applied, and FIG. 2 is a side view showing the electric injection molding machine according to the embodiment as viewed from the arrow in FIG. It is an elevational view taken along the line A-A, in which reference numeral 1 indicates a heath frame of an electric injection molding machine, reference numeral 2 indicates a fixed platen, and reference numeral 3 indicates a movable platen. The movable platen 3 is slidably fitted into a tie bar 4 installed horizontally on the fixed platen 2, and is driven by a mold clamping mechanism 5 of the injection molding machine. Reference numeral 6 designates an injection unit, which is integrally equipped with an injection cylinder 8 equipped with a nozzle 7 at its tip and a hopper 9 for supplying pellets or for temporary storage, and along the central axis of the injection cylinder 8, that is, the injection axis.
Move on base frame 1. The driving source of the injection unit 6 is a surf motor.

A fixed mold 10 and a movable mold 11 are attached to each of the fixed platen 2 and the movable platen 3, and the fixed mold 10 has a sprue bush 12 for filling the inside of the mold with resin from the nozzle 7. Or is provided.

A prismatic support rack 13 is erected on the back surface of the fixed platen 2 in parallel with the injection axis, and a movable member 14 is slidably but unrotatably fitted therein. The riet screw 16, which is the rotational output shaft of the surf motor 15 fixed to the end of the support rack 13, is screwed into a female plate carved in the approximate center of the moving member 14, and is slidably fitted into the support rack 13. The moving member 14 is moved along the injection axis.

One end of a swing arm 17 is pivotally attached to one side of the moving member 14, and an air cylinder 18 is pivotally attached to the other side of the moving member 14.
The platen 2 is oscillated in a plane parallel to the identification platen 2 using a driving source.

1 and 2 show the original position state in which the moving member 14 is separated from the platen 2, the air cylinder 18 is retracted, and the rod member 19 is separated from the injection axis in the radial direction of the injection axis. Therefore, a slight gap is formed between the tip of the rod member 7 member 19 and the fixed platen 2. When the air cylinder 18 extends in this state, the swing arm 17 moves to the second position.
The rod member 19, which is swung clockwise in the figure and held at the other end of the swing arm 17 in parallel to the injection axis via a vibrator 20, moves onto the injection axis.

The vibrator 20 is a vibrating device including a motor having an eccentric weight attached to the shaft, an excitation device, an intermittent drive air cylinder, or the like, and applies vibration to the rod member 19 in the axial direction.

A first driving means for moving the tip of the rod member 19 between the original position shown in FIGS. 1 and 2 and the end surface of the sprue bushing 12, which is the nozzle touch position,
3. Servo motor 15. It is composed of a linear motion mechanism 21 consisting of a lead screw 16, a moving member 14, etc., and a swing mechanism 22 consisting of a swing arm 17 and an air cylinder 18. The swinging mechanism 22 moves the rod member 19 in its original position away from the injection axis onto the injection axis, and the linear motion mechanism 21 moves the tip of the rod member 19 that has moved onto the injection axis further to the end face of the sprue bush 12. and move it.

The linear motion mechanism 21 also serves as a second driving means for moving the tip of the rod member 19 along the injection axis and fitting it into the sprue bush 12.

A camera 23 is mounted on the upper surface of the movable platen 3 to capture the sprue bush 12 of the stationary mold 10 in its field of view at the set mold open position of the movable platen 3, and constitutes a sensor for detecting the remaining sprue runner. The camera 23 receives a snap command from the control device of the injection molding machine, and the fixed side mold 1
Take an image of the parting line 0, perform grayscale gradation processing, compare it with a pre-taught reference image to detect residual sprue runner, and output a residual detection signal to the control device of the injection molding machine. . In addition, if it is difficult to distinguish the presence or absence of residual resin through gradation processing due to the color tone of the resin, the center temperature of the sprue bush 12 can be detected by an infrared sensor, and a comparison can be made by adding an allowable value to the reference temperature of the sprue bush 12. The configuration is configured to compare the value and the detected temperature and output a residual detection signal when the detected temperature is high.

In FIG. 3, reference numeral 100 is a control device for an injection molding machine that also serves as a control means for the sprue ejection device of this embodiment, and the control device 100 is a microprocessor for NC (hereinafter referred to as
It has a CPU (hereinafter referred to as CPU) 108 and a CPUll0 for a programmable machine controller (hereinafter referred to as PMC), and the PMC CPU 10 has a ROM 113 that stores sequence programs etc. that control sequence operations of the injection molding machine and temporary storage of data. RAM used for etc.
106 is connected. The NC CPUIO 3 has a ROMI 11 that stores a management program that controls the entire injection molding machine, and drives and controls the servo motors of each axis for injection, clamping, screw rotation, ejector, injection unit 6, etc. A servo circuit 101 is connected via a servo interface 107. In FIG. 3, only the servo motor 24 for the injection unit 6, the servo motor 15 for the linear motion mechanism 21, and the corresponding servo circuit 101 are shown.

The servo circuit 101 is connected to an NC CPU 10 via a servo interface 107 when the servo motor 15 is driven.
8, the position command pulses input at predetermined intervals are cumulatively stored, and the feedback pulses input from the pulse coder of the servo motor 15 are subtracted to calculate the position deviation with respect to the current command position. An error register that serves as a drive command and a servo motor 15
The current rotational position of the servo motor 15 is calculated by cumulatively storing the feedback pulses input from the pulse coder of
That is, a current position storage register for detecting the current position of the moving member 14 is provided.

Further, 105 is a non-volatile shared RAM composed of bubble memory or CMOS memory, and a memory section for storing NC programs etc. for controlling each operation of the injection molding machine, and various setting values regarding molding conditions, etc.

It has a setting memory section that stores parameters and macro variables. 109 is a bus arbiter controller (hereinafter referred to as BA
C), and the BAC 109 has an NC CPU 108.
and PMC CPU110° shared RAM105. Input circuit 104. Each bus of the output circuit 103 is connected, and the BA
The bus to be used is controlled by C109.

A cylinder drive circuit 25 that drives the air cylinder 18 and a vibrator drive circuit 26 that drives the vibrator 20 are connected to the output circuit 103, and the NC CPU 108
The air cylinder 18 and the vibrator 20 are controlled in a 0N10FF manner by a command from the controller. Furthermore, a camera 23 serves as a residual detection sensor for the sprue runner.
is connected to the output circuit 103, and the camera 23 detects the remaining sprue runner in response to a snap command from the NC CPU 108, and a residual detection signal from the camera 23 is manually input to the NC CPU 108 via the input circuit 104. It looks like this.

Further, 114 is a manual data input device with a CR7 display device (hereinafter referred to as CRT/MDI) connected to the BAC 109 via the operator panel controller 112, and displays various setting screens and work menus on the CRT display screen. By operating various operation keys (soft keys, numeric keys, etc.), it is possible to input various setting data and select setting screens. In addition, 102 is NC
The RAM is connected to the CPU 108 by bus and is used for temporary storage of data.

In the above configuration, the control bag a100 is
The CPL for PMC;
While performing sequence control, the NC CPU 108 distributes pulses to the servo circuits of each axis of the injection molding machine via the servo interface 107 to control the injection molding machine.

In this embodiment, the sprue ejecting device constituted by the linear motion mechanism 21 and the swing mechanism 22 is further driven based on the presence or absence of a residual detection signal from the camera 23 to automatically remove the runner remaining in the sprue bush 12. A program for "residual removal processing" for removing the residuals is stored in the shared RAM 105.

FIG. 4 is a flowchart showing an outline of the "residual removal process", and the "residual removal process" is performed by the NC CPU 108 at the stage when the movable platen 3 has retreated to the set mold opening position and the mold opening completion signal has been detected. This is executed as a process, and the sequence operation of the next step is not executed until this process is completed.

Therefore, while the "residual removal process" is being executed, it is the same as if the injection molding operation is interlocked.

The NC CPU 108, which has detected the mold opening completion signal and started the "residual removal process", first outputs a snap command to the camera 23, and performs photographing of the tZ-ting line of the stationary mold 10, grayscale gradation processing, and A remaining sprue runner determination process is executed and an input from the camera 23 is waited for (step Sl, step S2).

If the residual detection signal from the camera 23 is not detected, it is determined whether the sudden operation execution flag F is set (step S3), but if the previous molding operation has been performed normally, Alternatively, if the removal of the remaining sprue runner has already been completed and it is possible to restart the molding operation, the ejection operation execution flag F is not set, and the NC CPU 108 ends the "residual removal process". Then move on to the next sequence operation and continue the molding operation.

Steps S1 to S3 for each mold opening operation in one process
When residual sprue runner is detected while repeatedly executing the process, the NC CPUIO 3 executes the determination process in step S2, and then determines whether or not the ejecting operation execution flag F is set (step S4). ). If the ejecting operation execution flag F is not set, it means that the first removal operation for the detected residual will be executed, and the NC CPU 108 will set the ejecting operation execution flag F.
After setting and memorizing the start of the removal operation (step S
5) Output the injection unit retreat command and move the injection unit 6
Pulse distribution for the servo motor 24 is started, and the injection unit 6 is moved back in a direction away from the fixed platen 2 (step S6). Hereinafter, the value of the current position register for the servo motor 24 is sequentially detected and the injection unit 6 is
Determine whether the current position of has reached the set retreat position,
Wait until the injection unit 6 reaches the set retreat position (step 37).

Next, a cylinder extension command is output to the cylinder drive circuit 25 to drive the air cylinder 18, and the swing arm 17, which constitutes a part of the first drive means, swings clockwise in FIG. 19 is positioned on the injection axis (step S8). At this stage, the injection cylinder 8 and nozzle 7
Since the injection unit 6 is retracted together with the injection unit 6, there is no interference between the members (see FIG. 1).

Furthermore, a drive command is output to the vibrator drive circuit 26 to drive the vibrator 20 to vibrate the rod member 19 in the axial direction (step S9), and a linear motion mechanism advance command is output to distribute pulses to the servo motor 15. and start the first
．． Driving the linear motion mechanism 21 constituting the second driving means,
The rod member 19 is advanced along the injection axis in a direction approaching the fixed platen 2 (step 510). The final target position of the linear motion mechanism advance command is determined by passing the tip of the rod member 19 or the resin path in the sprue bush 12 to the stationary mold 1.
This is a value that protrudes to the 0 parting line. Thereafter, the value of the error register and the value of the current position register for the servo motor 15 are sequentially detected, and if the position deviation of the error register exceeds the range of the allowable set value ε, or the tip of the rod member 19 reaches the final target. Until the position is reached, pulse distribution is continued and the rod member 19 is advanced along the injection axis (Step S11. Step 512).

If the positional deviation of the error register exceeds the allowable set value ε before the tip of the rod member 19 reaches the final target position,
That is, if the determination result in step Sll is true, even if the servo motor 15 is driven with a predetermined torque corresponding to the value ε of the error register, the tip of the rod member 19 will not reach the sploop or the residual runner in the sosh 12. This means that it cannot be extruded. Therefore, the NC CPU 108 is a CRT/M
After displaying an alarm message on the display screen of D■ 114 (Stella 520), a linear motion mechanism retraction command is output and the rod member 19 is retreated to the linear motion drive start position (
Step S21. Step 522), a vibrator stop command is output to stop the vibration of the vibrator 20 (Step 523), and a cylinder retraction command is output to swing the swing arm 17 to completely return the rod member 19 to its original position. After returning (step 524), the ejecting operation execution flag F is initialized (step 525), and this "residual removal process" is ended. In this case, it is difficult to automatically remove the sprue runner, and the injection molding machine will stop with the mold open. Sprue runner removal is performed manually by an operator who detects an alarm message.

On the other hand, if the value of the current position register reaches the target value before the position deviation of the error register exceeds the allowable set value ε, that is, if the determination result of step S12 becomes true,
This means that the tip of the rod member 19 penetrates the resin path of the sprue bush 12 and protrudes to the parting line of the stationary mold 10. In this case, the NC CPU 108
After outputting a linear motion mechanism retraction command and retracting the rod member 19 to the linear motion drive start position (step S13° step 514), returns to step S1 and outputs a snap command to the camera 23, It is determined whether the remaining runners have been completely removed by the first removal operation (step S2).

If the removal of the remaining runner is incomplete, that is, if the determination result in step S2 is true, the process moves to step S10 via step S4, and then the processes of steps SIO to S14 are repeatedly executed to remove the injection axis. The rod member 19 located above and vibrating in the axial direction is advanced to perform the second and subsequent ejection operations, retrying to remove the remaining runner, and retracting the rod member 19 to the linear drive start position. let

In this way, if the remaining runners are reliably removed while executing the retry process, the determination result in step S2 becomes false, and the NC CPU 108 moves to step S3. Since the ejection operation execution flag F has already been set in the process of step S5 in the first removal operation, CP
U108 moves to step S15 and activates the vibrator 20.
stops driving, outputs a cylinder retraction command to swing the swing arm 17, completely returns the rod member 19 to its original position (step 516), and outputs an injection unit advance command to move the nozzle 7 through the sprue. After pressing the bush 12 against the end face (step S17, step 518) and initializing the ejection operation execution flag F (step 519), the sequence operation of the injection molding machine is permitted, the interlock is released, and the mold is opened. Continue to perform the following actions.

Note that when regulating the number of times the retry process is executed, the retry counter C is incremented by 1 in the process of moving from step S4 to step 310, and the retry counter C is
The value of is compared with the set number of retries N, and the processing from step S10 onward is executed until the value of counter C reaches N. Also, when the value of counter C reaches N,
Step S20 and step 323 to step S2
Execute the process in step 5. The initial value of the retry counter C is 0, and it is assumed that the retry counter C is initialized together with the processing in steps S19 and S25.

Furthermore, at the same time as flag F is set, measurement of the driving stop time of the injection molding machine, that is, the residence time t of the molten resin in the injection cylinder 8 is started, and after the process of step S16 is executed, the current value of the residence time is set to t. The current value t may be compared with the allowable time T, and if the current value t exceeds the set allowable time T, automatic purge processing and reweighing processing may be executed before proceeding to step S17. Instead of the measured value of the residence time, the value of the retry counter C can also be used as a criterion for determining whether or not automatic purging is necessary.

Note that a lead screw or the like driven by a servo motor may be used as the drive source for the swing arm 17 instead of the air cylinder 18. In this case, the rod member 19 in the current position is moved onto the injection axis and then the sprue is moved. It is not necessarily necessary to move the tip of the rod member 19 to the nozzle touch position, which is the end face of the rod member 12, and the tip of the rod member 19 can also be directly moved from the original position to the nozzle touch position using a proportional distribution control method. The movement of the rod member 19 is not limited to drive means such as air cylinders and servo motors, but various conventionally known drive sources can be used, and a direct-acting slide arm or the like can be used instead of the swing arm 17. You can also.

Effects of the Invention According to the sprue ejecting device of the present invention, it is possible to automatically remove the runner remaining on the sprue bush of the stationary mold during injection molding work, and moreover, the runner remaining on the sprue bush is removed. Since the molding operation of the injection molding machine is interlocked and the molding operation is stopped until it is removed, accidents such as molding defects and resin spouting due to backflow can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a side view showing the main parts of an electric injection molding machine according to an embodiment to which the sprue ejecting device of the present invention is applied, and FIG. 2 is a side view showing the electric injection molding machine according to the embodiment as viewed from the arrow in FIG. An elevational view taken along line A-A, FIG. 3 is a block diagram showing the main parts of the control device of the injection molding machine which also serves as a control means for the sprue ejecting device of the same embodiment, and FIG. 4 is an NC diagram of the same control device. 2 is a flowchart showing an outline of a "residual removal process" executed by the CPU. 1...Base frame, 2...Fixed platen, 3.
・Movable platen, 4... tie bar, 5... mold clamping mechanism, 6... injection unit, 7... nozzle, 8... injection cylinder, 9... hopper, 10... fixed side metal Mold, 11... Movable side mold, 12... Sprue bush,
13... Support rack, 14... Moving member, 15... Servo motor, 16... Lead screw, 17... Swinging arm, 18... Air cylinder, 19... Rod member,
20... vibrator, 21... linear motion mechanism, 22...
... Rocking mechanism, 23... Camera, 24... Servo motor, 25... Cylinder drive circuit, 26... Vibrator drive circuit, 100... Control device, 101...
Servo circuit, 102...RAM, 103...Output circuit, 104...Input circuit, 105...Shared RAM, 1
06・RAM, 107-・Servo interface, 1
08... CPU for NC, 109... Bus arbiter controller, 110... CPU for 1MC, 111.
...ROM, 112...operator panel controller, 113...ROM, 114...manual data input device with CRT display device. Figure 2

Claims (1)

[Claims] There is a sensor that monitors the mold mounted on the fixed platen of an injection molding machine and detects the residual sprue runner when the mold is opened, and a sensor that detects the position radially apart from the injection axis on the back side of the fixed platen. a rod member disposed parallel to the injection axis; a first driving means for moving the tip of the rod member between the original position and a nozzle touch position of the injection molding machine; a second driving means for moving the second driving means along the sensor; and upon receiving a residual detection signal from the sensor, an interlock is applied to the molding operation of the injection molding machine and an injection unit retreat command is output, and the first driving means is actuated. to move the tip of the rod member to a nozzle touch position of the injection molding machine, and then actuate the second driving means to move the rod member along the injection axis and fix the tip of the rod member. The platen is inserted into the sprue bush of the mold from the back side of the platen, the sprue runner remaining in the sprue bush is pushed out of the mold, and the second driving means is actuated to bring the tip of the rod member into contact with the nozzle of the injection molding machine. and control means for returning the rod member to the original position by operating the first driving means and outputting an injection unit advance command to release the interlock. ejection device.