JPH0550480A - Method for monitoring injection molding machine - Google Patents

Abstract

PURPOSE:To provide a general-purpose monitoring method capable of being easily adapted even to various injection molding machines. CONSTITUTION:The vibrations and operation sounds of the respective operation parts of an injection molding machine 1 are monitored at every molding processes by acceleration sensors G1-G4 and microphones M1-M3, and the stable states of the cycle times of the molding processes are monitored from the cycles of monitor signals and the generation of abnormality in the respective operation parts is monitored from the abnormality values of the respective monitor signals.

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 monitoring method for monitoring the stable state of the cycle time of the injection molding machine and the occurrence of an abnormality in each operating part.

[0002]

2. Description of the Related Art As a method for monitoring the stable state of the cycle time of the molding process and the occurrence of an abnormality in each operating part of an injection molding machine, for example, a method described in Japanese Patent Publication No. 12650 has been known. .. This is because the injection pressure of the injection molding machine, the position of the screw, the speed, the number of revolutions, the temperature of each part, etc. are measured for each molding process using pressure sensors, potentiometers, encoders, temperature sensors, etc. Compared with the standard value obtained when is a good product,
This is a method of monitoring the occurrence of an abnormality depending on whether or not it exceeds the range of the reference value.

[0003]

In the prior art described in the above publication, a large number of sensors such as a pressure sensor, a potentiometer, an encoder and a temperature sensor are required, but these sensors are injection molding machines. The types that can be installed and the installation method differ for each model of
In addition, a dedicated amplifier and dedicated input circuit to the microcomputer are required to match these sensors.
There is a problem that it cannot be easily applied to a wide variety of injection molding machines and lacks versatility.

Therefore, an object of the present invention is to provide a versatile injection molding machine monitoring method that can be easily applied to a wide variety of injection molding machines.

[0005]

In order to achieve the above-mentioned object, a method of monitoring an injection molding machine according to the present invention provides a vibration and an operation sound of each operating part of the injection molding machine by an acceleration sensor and a microphone for each molding process. The means is to monitor and monitor the stable state of the cycle time of the molding process from the cycle of the monitor signal, and also to monitor the abnormal occurrence of each operating portion from the abnormal value of each monitor signal.

Here, it is preferable that the acceleration sensor can be fixed to an arbitrary position of the injection molding machine by a magnet, a double-sided tape or the like. Further, it is preferable that the microphone be a type that can be easily attached to an arbitrary position of the injection molding machine and is of a proximity type that has a strong directivity and is hardly influenced by background noise.

[0007]

By adopting such means, the method of monitoring an injection molding machine according to the present invention requires only an acceleration sensor and a microphone that are easy to install as sensors, and an input circuit to an amplifier or a microcomputer. Since it can also be used for various purposes, it can be easily applied to a wide variety of injection molding machines and has versatility.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the accompanying drawings. FIG. 1 shows a schematic configuration of an injection molding machine to which one embodiment is applied.
A fixed platen 4 fixed to the column 3 with the upper mold 2 fixed to the lower surface, and a movable platen arranged below the fixed platen 4 and moved up and down along the column 3 with the lower mold 5 fixed to the upper face. 6 and 6. A nozzle 8 containing a screw 7 is arranged above the stationary platen 4, and the nozzle 8 can be moved up and down along the support column 3 via a cylinder 9 continuous to the upper end of the nozzle 8. The ejector 1 is provided below the movable platen 6.
0 is arranged so that the injection molded product is removed from the lower mold 5 when the movable platen 6 is lowered. Furthermore, the upper part of the screw 7 is a screw support cylinder 11 that can be raised and lowered along the support column 3.
A screw rotation pump 12 is fixed to the upper end of the screw 7 above the screw support cylinder 11 so as to be freely rotatable. Also, the two hydraulic pumps 13,
The injection molding machine 1 is additionally provided with a motor 14 and a motor 15 that drives them to rotate.

Here, as a sensor for monitoring the stable state of the cycle time of the molding process of the injection molding machine 1 and the occurrence of an abnormality in each operating part, for example, four acceleration sensors G1 to G1 are used.
G4 and three microphones M1-M3 are provided.

The acceleration sensors G1 to G4 can be easily fixed by a magnet or a double-sided tape. The acceleration sensor G1 is used for the ejector 10, the acceleration sensor G2 is used for the movable plate 6, and the acceleration sensor G3 is used for the cylinder 9.
Further, the acceleration sensor G4 is fixed to each of the screw support cylinders 11 and detects the vibration thereof. Further, the microphones M1 to M3 are of a proximity type and have a strong directivity and little influence of background noise, and are easily attached. The microphone M1 is located near the upper die 2 and the microphone M2 is a screw rotary pump. Microphones M3 are arranged in the vicinity of 12 and in the vicinity of the motor 15, respectively, and detect the operation sound thereof.

FIG. 2 shows a block configuration of a monitor signal processing circuit 16 which processes monitor signals detected by the acceleration sensors G1 to G4 and the microphones M1 to M3. The monitor signal processing circuit 16 includes a charge amplifier 17 that amplifies a monitor signal of an operation sound detected by the microphones M1 to M3, and a charge amplifier 18 that amplifies a monitor signal of acceleration vibration detected by the acceleration sensors G1 to G4. The monitor signal of the operating sound amplified by the charge amplifier 17 is input to the A / D converter 20 through the bandpass filter 19 that cuts the background noise, and an effective value circuit for obtaining the DC converted sound pressure level. It is input to the A / D converter 22 via 21, and further input to the A / D converter 22 with the same signal waveform.

On the other hand, the monitor signal of the vibration amplified by the charge amplifier 18 is input to the A / D converter 24 and the pulse generating circuit 25 via the effective value circuit 23 for obtaining the DC effective acceleration value, Further, the signal waveform as it is is input to the A / D converter 24. The output signals from the A / D converters 20, 22, 24 and the pulse generation circuit 25 are input to the microcomputer 27 via the CPU bus 26 to stabilize the cycle time of the molding process of injection molding and the respective operating parts. The occurrence of abnormalities is monitored.

Next, the operation of one embodiment will be described according to the progress of the molding process of the injection molding machine 1. Here, in the molding process of the injection molding machine 1, (1) mold clamping is started by raising the movable platen 6,
(2) Completion of mold clamping by stopping the movable plate 6, (3) Advancement of the nozzle 8 by lowering the cylinder 9, (4) Completion of nozzle touch by stopping the cylinder 9, (5) Screw by lowering the screw support cylinder 11. 7 forward (start injection),
(6) Screw 7 by stopping the screw support cylinder 11
(7) Start rotation of the screw 7 by the screw rotary pump 12 (reverse start), (8) Stop rotation of the screw 7 by the screw rotary pump 12 (reverse stop), (9) Nozzle 8 by raising the cylinder 9. (10) Recession stop of the nozzle 8 by stopping the cylinder 9, (11) Start of mold opening by lowering the movable plate 6, (12)
The mold opening stop by the movable platen 6 is stopped, (13) the ejector 10 starts to move forward, (14) the ejector 10 stops moving forward, (15) the ejector 10 starts to move backward, and (16) the ejector 10 moves backward to stop. It progresses by being performed sequentially. During the molding process, the acceleration sensors G1 to G4 and the microphones M1 to M3 detect the acceleration vibration and the operation sound of the corresponding operating parts, and the monitor signals are supplied to the charge amplifiers 17 and 18 of the monitor signal processing circuit 16. Is output to.

Therefore, for example, at the time of starting the mold clamping by raising the movable plate 6 in (1), the monitor signal of the acceleration vibration of the movable plate 6 detected by the acceleration sensor G2 is amplified by the charge amplifier 18, and this is the effective value circuit. By inputting to 23, the effective acceleration value of the movable platen 6 is obtained as a waveform signal converted into a direct current, as shown in FIG. By inputting this waveform signal to the pulse generation circuit 25,
A pulse signal of one pulse as shown in FIG. 3B is generated. Then, such signal processing is performed by another acceleration sensor G.
With respect to 2, G3, and G4, the pulse signal train as shown in (C) of FIG. 3 is obtained by sequentially performing the operations of (1) to (16).

In FIG. 3C, (1) shows a pulse signal corresponding to the start of mold clamping, (2) shows a pulse signal corresponding to the completion of mold clamping, and (1) and (2).
Indicates the time of the mold clamping process. Similarly (3)
Reference numerals (16) to (16) indicate pulse signals corresponding to the respective operations (3) to (16) described above. From these intervals, the time delay of each operation during the molding process of the injection molding machine 1, that is, the cycle time Steady state can be monitored.

FIG. 4 shows signal processing when the insert molding between the upper mold 2 and the lower mold 5 is clamped in an abnormal state during the mold clamping operation. In this case, the movable plate 6
The acceleration sensor G2 fixed to detects the abnormal acceleration vibration, and the microphone M1 arranged near the upper mold 2 detects abnormal noise. Therefore, the charge amplifier 18 detects a waveform of an abnormally large acceleration amplitude, and the effective value circuit 21 detects an abnormally large sound pressure level, so that the occurrence of an abnormality in the mold clamping process can be monitored.

Similarly, based on the monitor signal detected by the microphone M2, it is possible to monitor the rotation unevenness of the screw 7 during measurement. Also, the microphone M3
Thus, it is possible to monitor the abnormality of the actuator for each process from the abnormality of the operating noise of the motor 15. For example, when the rubber material is scorched (cured) in the injection step of the rubber material, the flow resistance is increased to increase the cylinder resistance.
Since the driving sound of the hydraulic pumps 13 and 14 that press the button is unalum, such a situation can be monitored from the abnormal sound.

Here, in the method of monitoring the injection molding machine 1 according to the embodiment, only the acceleration sensors G1 to G4 and the microphones M1 to M3, which are easy to install, need to be prepared as sensors, and the monitor signal processing circuit 16 and the microcomputer. Since it can also be used as an input circuit to the 27, it can be easily applied to a wide variety of injection molding machines, and versatility can be obtained.

[0019]

As described above, according to the present invention,
Since it is sufficient to prepare only an acceleration sensor and a microphone that are easy to install as sensors, and can also be used as an input circuit to an amplifier or a microcomputer, it can be easily applied to a wide variety of injection molding machines, and versatility can be obtained.

Further, the vibration of each operating part of the injection molding machine is monitored by an acceleration sensor and the operating sound is monitored by a microphone, so that abnormal insertion of the insert molded product, cracking of the molded product at the time of release, etc. Also, it is possible to monitor the occurrence of abnormalities that cannot be inspected or detected in the normal molding process, and the monitoring function for process automation can be improved.

[Brief description of drawings]

FIG. 1 is a front view showing, as a partial cross section, a schematic configuration of an injection molding machine to which an embodiment of the present invention is applied.

FIG. 2 is a block configuration diagram of a monitor signal processing circuit used in one embodiment.

3 (a), (b), and (c) are waveform diagrams of acceleration effective value, voltage, and pulse voltage processed by a monitor signal processing circuit, respectively.

4A and 4B are waveform diagrams of acceleration amplitude and sound pressure level processed by a monitor signal processing circuit, respectively.

[Explanation of symbols]

 1 …… Injection molding machine 2 …… Upper mold 3 …… Posts 4 …… Fixed plate 5 …… Lower mold 6 …… Movable plate 7 …… Screw 8 …… Nozzle 9 …… Cylinder 10 …… Ejector 11 …… Screw Support cylinder 12 ... Screw rotary pump 13, 14 ... Hydraulic pump 15 ... Motor 16 ... Monitor signal processing circuit 17, 18 ... Charge amplifier 19 ... Bandpass filter 20, 22, 24 ... A / D converter 21, 23 ... Effective value circuit 25 ... Pulse generation circuit 26 ... CPU bus 27 ... Microcomputer G1, G2, G3, G4 ... Acceleration sensor M1, M2, M3 ... Microphone

Claims (1)

[Claims] 1. A vibration and an operating sound of each operating part of an injection molding machine (1) are monitored for each molding process by an acceleration sensor (G1 to G4) and a microphone (M1 to M3), and the period of the monitor signal is monitored. A method for monitoring an injection molding machine (1), which comprises monitoring a stable state of cycle time of a molding process and monitoring occurrence of an abnormality in each operating portion from an abnormal value of each monitor signal.