JPH05228972A - Quality monitor for injection molding - Google Patents

Abstract

PURPOSE:To monitor the quality of a molded form stably by installing a converter converting the vibrations of a mold into an electric signal outside the mold, comparing vibrations at the time of injection molding operation with data at the time of the molding of a nondefective and giving an alarm when there is abnormality. CONSTITUTION:An acceleration sensor 1 is mounted outside a mold in an injection molding machine as a converter. The sensor 1 converts vibrations generated in the mold at the time of injection molding into an electric signal and outputs the signal, and the electric signal is transmitted over an analyzer 3 through an amplifier 2 and recorded. On the other hand, a trigger signal conformed to the start timing of one-time injection molding process is transmitted over the analyzer 3 from the injection molding machine, and the recording of a vibrational signal is synchronized with every injection molding operation. The magnitude of a shock generated in the mold and timing, the magnitude of vibrations at the time of the inflow of a resin, a frequency component and a duration are analyzed and compared with data at the time of the molding of a nondefective, and an alarm is given when there is abnormality.

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 quality control monitoring device for plastic molded products.

[0002]

2. Description of the Related Art In order to stabilize the quality of a molded product produced by an injection molding machine, it is necessary to always control the operating conditions of the molding machine optimally. In order to maintain the quality of the molded product even with fluctuations in itself, it is effective to detect and analyze the state inside the mold in which the molded product is completed. Conventionally, by detecting the temperature and pressure as the state inside the molding machine mold and analyzing the state of the plasticized resin inside the mold, the operating conditions of the molding machine can be set to obtain good molded products. , Methods of monitoring molding quality have been attempted.

[0003]

In this conventional method for monitoring the quality of molded products, it is necessary to perform fine processing on the mold and insert a temperature and pressure converter, so that the design and manufacture of the mold are not possible. It was difficult. In addition, there is a problem that the converter, which is constantly exposed to high temperature and high pressure resin, has a large stress and cannot maintain stable performance for a long period of time.

[0004]

SUMMARY OF THE INVENTION A quality monitoring device for an injection-molded article according to the present invention comprises a converter attached to the outside of a mold and converting the vibration of the mold into an electric signal, and a signal from the converter. And an analyzing device for analyzing the change on the time axis and the frequency component and comparing and analyzing with the previously stored data at the time of molding a good product, and a means for issuing an alarm when this analysis result is abnormal. There is.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, (a) is an overall configuration diagram, and (b) is a waveform diagram showing an example of a vibration signal of a mold in one injection molding operation.

In this embodiment, an acceleration sensor 1 as a converter which is attached to the outside of a mold in an injection molding machine and converts the vibration of the mold into an electric signal, and a signal from the acceleration sensor 1 is recorded and recorded. Analyze changes on the time axis and frequency components
The analysis device 3 for comparison and means for issuing an alarm when the analysis result is abnormal are provided.

In this embodiment having such a configuration, the signal of the acceleration sensor 1 attached to the outer peripheral portion of the mold provided in the injection molding machine captures the vibration generated in the mold during injection molding and outputs an electric signal. Output. This signal is amplified by an amplifier 2 into an appropriate signal and then given to an analysis device 3 mainly composed of a computer. In the analysis device 3, the vibration signal of the mold is recorded by the function of performing analog-digital conversion and storing it in the memory. On the other hand, the injection molding machine gives a trigger signal to the analysis device 3 in synchronization with the start timing of one injection molding process to synchronize the recording of the vibration signal with each injection molding operation.

In FIG. 1B, the data recorded as described above is recorded 1
An example of the waveform of the vibration signal of the mold in one injection molding operation is shown. When the mold is opened and closed and the molded product is pulled out, a shack is generated in the mold, and when the resin is injected, a slight vibration is generated due to the flow into the mold. These behaviors are analyzed in the analysis device 3 into quantitative elements such as the magnitude and timing of shock, the magnitude of vibration at the time of resin inflow, the frequency component, and its duration. For these data, a certain allowable width is set for the data when a good product is molded, and a comparative judgment is made.At the same time, it is checked whether abnormal vibration appears, and a good product is molded in the mold. When the behavior of vibration different from that during the operation occurs, an alarm is issued via the interface.

[0010]

As described above, according to the present invention, since the molding condition is monitored by the vibration converter attached to the outside of the mold, there is no obstacle in designing and manufacturing the mold and the performance of the converter is improved. It has an effect that it is hard to be damaged, and therefore the quality of the molded product can be stably monitored.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, (a) is an overall configuration diagram, and (b) is a waveform diagram showing an example of a vibration signal of a mold in one injection molding operation.

[Explanation of symbols]

 1 Accelerometer 2 Amplifier 3 Analyzer

Claims (2)

[Claims] 1. A converter attached to the outside of a mold for converting the vibration of the mold into an electric signal, and a signal from this converter is recorded to analyze the change on the time axis and the frequency component. An injection-molded product quality monitoring device, further comprising: an analysis device that compares and analyzes previously stored data during molding of a good product, and a unit that issues an alarm when the analysis result is abnormal. 2. The quality monitor for injection-molded articles according to claim 1, wherein the converter is an acceleration sensor.