TWI566061B - The management system of the mold clamping device - Google Patents

Description

Molding device management system

The present invention relates to the management of a mold clamping device for press molding, injection molding, die casting molding, and the like, and more particularly to the management of a mold.

Since it is difficult to accurately detect the state of the mold of the mold clamping device, the number of shots (the number of mold clamping times) is limited, and if the predetermined number of shots is reached, the mold is maintained. If it is maintained too late, the fatigue or deformation of the mold will become obvious, which will not only make the maintenance large-scale, but also affect the quality of the product. Therefore, a sufficient safety rate is reserved for the above-mentioned number of shots, and maintenance is performed early. Excessive maintenance of this system can result in waste.

Patent Document 1 (JP2007-155335) proposes that an acceleration sensor is attached to a mold to measure the dynamic deformation of the mold. However, Patent Document 1 judges that it is necessary to correct one of the upper and lower molds after the molded article has a defective condition, and it is not necessary to determine whether maintenance is required before the defective product is produced.

Patent Document 2 (JP 2010-137542) proposes to use the output energy of the servo motor for deformation of the mold, and calculate the mold clamping force based on the integrated value of the output energy of the servo motor. However, it is not clear whether it is possible to judge whether maintenance is required based on the calculated clamping force before the defective product is produced.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] JP2007-155335

[Patent Document 2] JP2010-137542

An object of the present invention is to eliminate the waste of maintenance for a mold that requires maintenance and a mold that requires no maintenance, according to the number of shots.

The present invention relates to a management system for a mold clamping device that performs mold clamping by pressing a movable mold against a fixed mold, and is provided with a sensor that measures a fixed mold and a movable mold in a mold to be inspected. The interval and the judging means determine whether the mold of the inspection object needs to be maintained by comparing the signal of the sensor with the signal of the sensor on the normal mold.

Fig. 7 is a view showing the data when the interval between the fixed mold and the moving mold is measured with respect to time using a line sensor. Even if the position of the motor end is fixed, the interval changes during the period of about 100 msec, and the high-frequency component is included in the sensor signal in addition to the exponential component that moves to the stable position. The change in the interval between the dies represents a process of deforming the mold due to the mold clamping, and the high frequency component indicates that the mold vibrates during the mold clamping process. Moreover, the vibration of the mold is related to the stress acting on the mold. By measuring the interval between the fixed mold and the moving mold in this way, a signal indicating the state of the mold can be obtained. If the signal is compared with the sensor signal from the normal mold, it can be judged whether maintenance is required.

Preferably, the signal of the sensor mounted on the mold in the stable period is used as the signal of the sensor of the normal mold. After the mold is manufactured or just after maintenance During the transition period (initial), it moves to the stable period, and then moves to the unstable period, and fatigue or deformation becomes apparent. Therefore, the signal from the mold in the stable period before the transition to the unstable period from the initial period can be set as the signal from the normal mold. Furthermore, the length of the initial duration and the duration of the stabilization period can be known from experience, as long as the signal from the mold which can be expected to be safe in the stable period is used as the signal from the normal mold. Furthermore, the signal from the mold just after manufacture or just after maintenance can be added to the signal from the normal mold.

Moreover, preferably, the judging means is to use the time series data of the signal of the sensor for the judgment of whether maintenance is required. The use of time series data refers to the use of the trajectory of the sensor signal, the use of the difference from the previous signal, etc., and indicates that not only the current sensor signal but also the past sensor signal is used to determine whether it needs to be performed. maintain. In this way, it is possible to more accurately determine whether maintenance is required.

Preferably, the sensor is mounted to a stationary mold or a moving mold. By attaching the sensor to a fixed mold or moving mold that is actually clamped, when the mold is moved while clamping, a sensor signal that more clearly indicates how the state of the mold changes or the like is obtained.

Preferably, the wireless communication terminal is provided with a signal for transmitting a sensor. The conventional mold clamping device is not formed to mount the sensor to the mold and to transmit data to the analysis device. Therefore, it is preferable to provide a wireless communication terminal to transmit data to the determination means via a controller having a memory clamping device or via a wireless LAN (Local Area Network).

More preferably, it is constructed in such a way that the position of the sensor signal on the mold of the inspection object is proportional to the distribution of the sensor signal on the normal mold. Potential, to determine whether maintenance is needed. In this way, for example, the signal from the mold in the stable period can be used as the sensor signal from the normal mold, and the mold is abnormally extracted from the position of the signal relative to the distributed mold, that is, the tendency to change from the position. Information such as the movement, bending of the mold, etc., to determine whether maintenance is required.

Preferably, there is provided means for mounting the sensor in a plurality of fixed molds or a plurality of moving molds, and determining the tendency of the difference between the signals of the plurality of sensors. The bending of the mold, the decrease in the parallelism between the fixed mold and the moving mold, and the decrease in the accuracy of the driving system can be detected based on the difference between the signals of the plurality of sensors, in particular, the difference between the signal waveforms. Moreover, by analyzing the trend, it is possible to judge whether the state of the mold or the like is stable or worse; and it is possible to detect that the difference of the waveform exceeds the allowable range.

As a sensor for measuring the interval between the fixed mold and the moving mold, for example, a wired sensor, an electrostatic capacitance sensor, an eddy current sensor, or the like can also be used. If the sensors are mounted on a plurality of fixed molds or moving molds, they can be judged more accurately. Further, it is preferable to provide a sensor for measuring the temperature of the mold (whether the cooling is appropriate and the temperature distribution in the mold, etc.) in addition to the sensor for measuring the interval between the fixed mold and the moving mold, and the inside of the measuring mold. The sensor of the stress, the sensor that measures the acceleration acting on the mold (the impact at the time of the impact of the mold, and the vibration generated by the propagation of the stress).

2‧‧‧Molding device

4‧‧‧ Lower frame

6‧‧‧ upper frame

8‧‧‧Mold

10‧‧‧Fixed mould

12‧‧‧Mobile mold

14‧‧‧ Guide column

16‧‧‧Guide bushing

18‧‧‧ Guide pin

20‧‧‧Guide bushing

22‧‧‧Pipe

24‧‧‧Line sensor

26‧‧‧ reference board

28‧‧‧ strain sensor

30‧‧‧Sound Sensor

32‧‧‧Temperature Sensor

34‧‧‧Communication unit

35‧‧‧Shell

36‧‧‧Sensor head

38‧‧‧Magnetic rod

40‧‧‧ reference board

42‧‧‧Magnetic mark

44‧‧‧Sliding members

45‧‧‧Connecting components

46‧‧‧ Spring

47‧‧‧ditch

48‧‧‧stops

50‧‧‧Servo motor

52‧‧‧Crank mechanism

54‧‧‧Analytical device

56‧‧‧Low-pass filter

58‧‧‧High-pass filter

60‧‧‧Interval division

62‧‧‧ Frequency Decomposition Department

64‧‧‧Time series memory

66‧‧‧ Cluster Analysis Department

70‧‧‧Processing circuit

Figure 1 is a front elevational view of the main part of the mold clamping device.

Fig. 2 is a cross-sectional view showing the main part of the line sensor.

Figure 3 is a block diagram of a clamping device and its management system.

Figure 4 is a diagram showing the processing before the sensor signal.

Figure 5 is a diagram showing cluster analysis.

Figure 6 is a graph showing the results of cluster analysis.

Fig. 7 is a view showing temporal changes of the signal of the line sensor during mold clamping.

Fig. 8 is a plan view showing an example in which four line sensors are attached to a fixed mold.

Fig. 9 is a view schematically showing temporal changes of signals of four line sensors at the time of mold clamping.

Figure 10 is a block diagram showing the processing circuit for the material of Figure 9.

Hereinafter, preferred embodiments for carrying out the invention are shown. The scope of the present invention should be determined based on the scope of the claims, the description of the specification, and the well-known technology in the field, and the understanding of the ordinary skill in the art to which the invention belongs.

[Examples]

1 to 7 show an embodiment. In the drawings, the reference numeral 2 is a mold clamping device, and although it is shown as a pressing device, it may be an injection molding device or a die casting molding device. The component symbol 4 is a lower frame, 6 is a movable upper frame, and a mold 8 is attached between the lower frame 4 and the upper frame 6. The component symbol 10 is a fixed mold, 12 is a moving mold, 14 is a guide post or a die bar, 16 is a guide bushing, 18 is a guide pin or a locating pin, and 20 is a guide bush. Further, a pipe 22 for cooling water is provided in the molds 10 and 12. Furthermore, the structure of the mold clamping device 2 and its components are arbitrary.

The component symbol 24 is a line sensor, and 26 is a reference plate, and the height of the movable mold 12 based on the fixed mold 10 is measured by these measurements. Furthermore, it can also be determined The height of the fixed mold 10 based on the moving mold 12 or the height of the molds 10 and 12 based on the lower frame 4 may be measured. The component symbol 28 is a strain sensor, and is composed of, for example, a load cell, and measures the stress acting on the molds 10 and 12. The component symbol 30 is a sound sensor for detecting sound waves occurring when the molds 10, 12 are in contact to perform mold clamping. The component symbol 32 is a temperature sensor, and the temperatures of the molds 10, 12 are measured to detect the heat generated by the mold clamping process, and it is checked whether or not the cooling water is sufficiently utilized for cooling.

The sensors 24, 28-32 are attached to the mold 8, preferably to the molds 10, 12, and more preferably to the vicinity of the chamber for the mold clamping process. The sensors may also be provided one by one, or may be provided in plurality, or other sensors such as an acceleration sensor for detecting the vibration of the molds 10 and 12 may be provided. Although it is not necessary to provide all of the sensors 28 to 32, since the line sensor 24 provides important information such as the distance between the molds 10 and 12, it must be set, and the number of the sets may be one, but preferably Set a plurality of.

FIG. 2 shows the construction of the line sensor 24. The component symbol 35 is a housing, 36 is a sensor head, and a plurality of coils and signal processing circuits are disposed therein. The reference numeral 38 is a magnetic rod, and both ends thereof are attached to the reference plate 40 and the connecting member 45, and magnetic marks 42 in which magnetic bodies and non-magnetic bodies are alternately arranged are provided along the longitudinal direction of the magnetic rod 38. Instead of the magnetic body and the non-magnetic body, the surface of the magnetic rod 38 may be magnetized so that the polarity alternates. The slide member 44 extends in parallel with the magnetic rod 38 from the reference plate 40, and the magnetic rod 38 and the slide member 44 are coupled by the joint member 45. The magnetic rod 38 and the slide member 44 are coupled to the movable mold 12 by the spring 46. can. The sliding member 44 slides along the groove 47 and restricts the movement toward the moving mold 12 side by the stopper 48. Furthermore, the construction of the line sensor 24 itself can be arbitrary. A suitable elastomer can also be used instead of the spring 46.

The operation of the line sensor of Fig. 2 will be described below. If the moving mold 12 of FIG. 1 is lowered and the reference plate 26 strikes the reference plate 40 of the line sensor 24, the magnetic rod 38 moves downward. Moreover, the sensor head 36 reads the phase of the magnetic marker 42 relative to the sensor head 36 and translates to the vertical position of the reference panel 40. Since the reference plate 40 is energized to the movable mold 12 side by the spring 46, it is lowered integrally with the reference plate 26, and does not vibrate without leaving the reference plate 26. Thereby, the height of the moving mold 12 with the fixed mold 10 as a reference can be read.

Figure 3 shows the main part of the mold clamping device 2 and its management system. The mold clamping device 2 raises and lowers the upper frame 6 and the upper mold (moving mold) 12 by the servo motor 50 via the crank mechanism 52 or a toggle mechanism (not shown). The distance between the molds 10, 12 is measured by the line sensor 24, and the stress acting on the molds 10, 12 at the time of mold clamping is measured by the strain sensor 28, and the sound sensors are used to detect the molds 10, 12 at the time of mold clamping. The sound waves that occur. Moreover, the temperature of the molds 10, 12 is detected by the temperature sensor 32. Further, in FIG. 1, although the sensors 28 to 32 are provided on both the upper and lower molds 10 and 12, the sensors 28 to 32 may be provided only in one of the upper and lower molds 10 and 12. .

The servo motor 50 inputs the encoder signal or the signal of the encoder signal to the position of the moving mold 12, and inputs it to the communication unit 34, and transmits the signal to the sensors 24, 28~32 via the wireless LAN or the like. It is sent from the communication unit 34 to the analysis device 54. Alternatively, the signals from the sensors 24, 28-32 are sent from the communication unit 34 to the controller of the mold clamping device 2, stored in the memory of the controller, and sent from the controller of the mold clamping device 2 to the analysis device 54. There are a plurality of mold clamping devices 2 of the same type in the factory, and the above data is sent from the mold clamping device 2 to the analysis device 54. Analytical load The 54 can be set in the workshop to analyze the data from the clamping device in the workshop, or can be set away from the workshop to analyze the data from the clamping devices of the plurality of workshops.

Figure 4 shows the previous processing in the analysis device. The signal of the line sensor is smoothed by the low-pass filter 56, and the high-frequency component is extracted by the high-pass filter 58, and is divided into, for example, three intervals in the initial stage, the middle stage, and the end of the mold clamping, and is utilized. The frequency decomposition unit 62 is decomposed into respective frequency components. From the signal of the line sensor, the signal of the servo motor encoder, the temperature signal of the mold, and the signals of other sensors, a signal for clamping can be obtained. The temperature signal of the mold and the signals of other sensors can be decomposed into frequency components or directly processed by the original waveform data. The time-series data for the signals is stored in the time-series memory 64 as time-series data arranged in chronological order. The time series indicates the order of the multiple clamping timeliness. The time series data is the data of each mold, even if the clamping device 2 is the same, but the different materials are different as long as the molds are different. Moreover, time series memory 64 memorizes signals from a plurality of clamping devices.

The low frequency component of the low pass filter 56 in the signal of the line sensor indicates how the mold follows the action of the servo motor. The target value of the encoder on the servo motor side can be changed by using the difference between the signal of the line sensor and the target value at the end of the mold clamping. Further, the difference between the signal of the servo motor encoder and the low-frequency component of the signal of the line sensor indicates the delay caused by the deformation of the mold due to the intermediate mechanism such as the crank mechanism and the contact with the upper and lower molds. If the high-frequency component that has passed through the high-pass filter 58 is frequency-decomposed, the vibration of the mold due to the contact of the upper and lower molds can be observed. This vibration system indicates the force applied to the mold and the deformation of the mold at the time of mold clamping.

If the strain sensor is used to measure the stress applied to the mold, it can be inferred. The vibration and deformation of the mold caused by the stress applied to the mold during mold clamping. Furthermore, the signal of the strain sensor is the same type of signal as the high frequency component of the signal of the line sensor. According to the signal of the sound sensor, the waveform of the sound wave generated when the upper and lower molds are in contact can be observed, which is a signal indicating the condition of the mold contact. According to the signal of the temperature sensor, the signal of whether the cooling of the mold is appropriate can be obtained, and the degree of thermal expansion of the mold can also be calculated. Further, the change of the signals, for example, the difference from the past average value, or the difference from the previous signal, can also be used as a signal indicating the stability of the mold.

The signal stored in the time-series memory 64 includes a signal having a normal mold clamping device, that is, a mold clamping device of a normal mold and a normal drive mechanism, and a signal from a mold clamping device to be inspected. Moreover, the main purpose of the inspection of the mold clamping device is to specify a mold that requires maintenance before the product is in a bad condition. Therefore, the inspection of the drive mechanism of the mold clamping device is omitted below, and only the inspection of the mold is described.

Shortly after the mold is manufactured, there is a period of initial instability (initial period). If it passes through this period, it will move to a stable period, and finally it will reach a period of unstable performance (unstable period), and maintenance is necessary. Moreover, the more times the mold clamping is performed during the unstable period, the large-scale maintenance is required. Therefore, the goal is to detect as early as possible that it has entered an unstable period. After the manufacture and maintenance of the mold after the mold is similar, there is also an unstable period immediately after maintenance, a stable period thereafter, and a final unstable period. Therefore, regarding which mold is in a stable period, it can be known from the history of the mold, and the signal from the mold in the stable period can be set as a normal signal, which will come from a long time after the manufacture, or a long time after the maintenance. The signal of the mold is set as the inspection object.

As shown in FIG. 5, the signals from the time series memory 64 are classified into normal signals and inspection target signals. Using the cluster analysis unit 66 to create a normal signal The cluster sets the inspection target signal away from the cluster as an abnormal signal to perform maintenance on the mold, and at least makes it a candidate for maintenance.

Fig. 6 schematically shows a cluster analysis, where the signal is represented as a three-dimensional signal. If a normal signal is collected, a cluster is generated, and the signal signal that is far from the cluster is expressed as a mold that requires maintenance. Therefore, using cluster analysis, it is possible to specify a mold that requires maintenance. Time series analysis is performed in order to be detected before the cluster is largely deviated. For example, even if the signal of the same a is advanced to the boundary of b, c, a and the cluster as indicated by the solid line in Fig. 6, maintenance is necessary. When the d, e, a and the inside of the boundary of the cluster are stopped as shown by the broken line in Fig. 6, maintenance is not required immediately. Therefore, if the cluster analysis unit 66 is used to determine whether to leave the cluster or stay in the cluster based on the trajectory of the signal, it is possible to specify the mold that has started to be out of the stable period.

Fig. 7 shows the signal waveform of the line sensor at the end of the mold clamping when the servo motor is feedback-controlled by the encoder. Even if the position of the motor end (the rotation angle of the motor output shaft) is fixed, the interval between the dies will be gradually reduced until 80 msec, and there will be a large period of vibration at the end. These vibration systems indicate the process in which the upper and lower molds are pressed against one side to complete the mold clamping. Moreover, since it is difficult to directly judge whether it is normal or necessary to perform maintenance according to the waveform of Fig. 7, it is decomposed into frequency components, and it is judged whether maintenance is required according to whether or not the signal of the mold leaving the stable period is required.

In the embodiment, although the signal from the line sensor or the like is decomposed into frequency components, the signal waveform may be directly analyzed, or the characteristic amount such as the amplitude of the signal may be extracted for analysis. Regarding the signal from the line sensor, the most important is the final stage of the mold clamping, and the importance is lower before the mold starts to contact. Therefore, it is also possible to perform clustering after the signal from the line sensor or the like is subjected to wavelet transform. analysis. Although cluster analysis is used in the analysis of whether maintenance is required, a neural network using signals from normal molds as an instruction signal can also be used. Alternatively, the parameters for judging the signal of the normal mold and the signal of the mold to be maintained may be obtained by judging and analyzing, and the judgment may be made. Moreover, it is not necessary to obtain a signal for each closed mode, for example, the frequency can be obtained once every other day, or once every hour. Further, the mold clamping device is not limited to the servo drive, and may be a hydraulic drive or the like. When there is no other type of mold and there is no signal from other molds used as a normal signal, the signal from the same mold that has passed the stable period after the initial period of manufacture can be used as a normal signal. Further, the line sensor 24 may be additionally provided for the ball screw, the toggle mechanism, and the like of the driving mechanism of the mold.

If the four line sensors 24 are mounted on the fixed mold 10 as shown in FIG. 8, the signal waveforms x1(t) to x4 as shown in FIG. 9 can be obtained from the four line sensors 24 when the mold is closed. t). If the clamping is performed ideally, the signal waveforms x1(t)~x4(t) will be identical, and the difference between the signal waveforms x1(t)~x4(t) will increase corresponding to the deviation from the ideal clamping. . The signal waveform x1(t)~x4(t) is processed by the processing circuit 70 of FIG. 10, and the average waveform X(t) and the signal waveform x1(t) of the signal waveform x1(t)~x4(t) are output. The dispersed waveform Y(t) of x4(t). Furthermore, the dispersed waveform Y(t) represents the difference between the signal waveforms x1(t)~x4(t). Further, it is preferable to output a time average X1 to Xm of the average waveform X(t) and a time average Y1 to Ym of the dispersed waveform Y(t) when the primary clamping is divided into, for example, m sections. In addition to this, the average waveform X(t) and the spectrum of the dispersed waveform Y(t), the average waveform X(t), and the peak value of the dispersed waveform Y(t) may be output.

If the signals are processed as shown in Figures 4 to 6, they can be checked. The bending of the molds 10, 12, the decrease in the parallelism of the molds 10, 12, and the decrease in the accuracy of the drive system are measured. In particular, it is possible to manage the trend of the dispersed waveform Y(t) or its time average Y1~Ym, and determine whether maintenance is required according to the following contents: whether the trend is stable, whether the dispersion is gradually increasing, and whether the dispersion is within the allowable range. .

The embodiment has the following features: 1) monitoring the spacing of the upper and lower molds 10, 12 by using the signal of the line sensor 24; 2) using the signal of the line sensor 24, and the signals of other sensors such as a temperature sensor The state of the molds 10 and 12 is comprehensively detected; 3) the signal from the normal mold is used as the command signal, and the signal of the departure command signal is extracted from the signal from the mold to be inspected. Thereby, it is possible to specify the mold that has moved to the unstable period in advance; 4) by using the time series of signals from the mold, it is possible to specify the mold to be repaired earlier, or more precisely, only the mold to be maintained. ;5) Unlike the case of maintenance according to the number of shots, unnecessary maintenance is not performed.

6‧‧‧ upper frame

10‧‧‧Fixed mould

12‧‧‧Mobile mold

22‧‧‧Pipe

24‧‧‧Line sensor

28‧‧‧ strain sensor

30‧‧‧Sound Sensor

32‧‧‧Temperature Sensor

34‧‧‧Communication unit

50‧‧‧Servo motor

52‧‧‧Crank mechanism

54‧‧‧Analytical device

Claims (7)

A management system for a mold clamping device that performs mold clamping by pressing a movable mold against a fixed mold; and a sensor that measures an interval between a fixed mold and a movable mold in a mold to be inspected; The means for judging, if the mold is subjected to a long period of time after manufacture or maintenance, as a mold that moves from the stable period to the unstable period, the sensor that is mounted on the mold in a stable period and measures the interval between the fixed mold and the moving mold The signal is set to the signal of the sensor on the normal mold, and the position of the signal of the sensor on the mold of the inspection object relative to the distribution of the signal of the sensor on the normal mold is used to determine whether the inspection is required. The mold of the object is maintained. For example, the management system of the mold clamping device of the first application of the patent scope, wherein the signal of the sensor mounted on the mold in the stable period is used as the signal of the sensor of the normal mold. For example, in the management system of the clamping device of claim 1, wherein the determining means is to use the time series data of the sensor signal for determining whether maintenance is required. The management system of the mold clamping device of claim 1, wherein the sensor is mounted on a fixed mold or a movable mold. A management system for a mold clamping device according to claim 1, wherein a wireless communication terminal having a signal for transmitting the sensor is provided. The management system of the mold clamping device of claim 1 is configured to: according to the trend of the position of the sensor signal on the mold of the inspection object relative to the distribution of the sensor signal on the normal mold, Determine if maintenance is required. The management system of the mold clamping device of claim 1, wherein the sensor is mounted in a plurality of fixed molds or a plurality of moving molds, and the difference between the signals of the plurality of sensors is determined. The means of the trend.