JPH0238916B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a monitoring device for an injection molding machine, and is particularly suitable for monitoring abnormalities around a mold of an injection molding machine.

Conventionally, as a monitoring device for this type of injection molding machine, the appearance of the object to be monitored, such as the mold or objects around it, is converted into a video signal by an imaging device, and this video signal is displayed on a cathode ray tube. A method has been proposed in which a brightness sensor is attached to the display surface of the cathode ray tube, and the presence or absence of an object is confirmed by utilizing the fact that the brightness on the cathode ray tube changes depending on the presence or absence of an object.

However, according to this method of detecting the brightness on the cathode ray tube, the brightness sensor for detecting the brightness on the display surface is attached to the display surface depending on the position of the object to be monitored. In addition, there is a problem that there is a certain limit to miniaturizing the overall configuration because a relatively large cathode ray tube must be prepared, and furthermore, it is difficult to attach a brightness sensor to the display surface. Depending on the state, external light may enter the sensor and noise may be included in the brightness detection results.

The present invention has been made in consideration of the above points, and by electrically processing a video signal obtained by an imaging device, it is possible to confirm the presence or absence of an object without requiring complicated labor and with high accuracy. This paper attempts to propose a monitoring device for an injection molding machine as described above.

An embodiment of the monitoring device for an injection molding machine according to the present invention will be described in detail below with reference to the drawings.

In FIG. 1, the injection molded product, which is the monitored object of the injection molding machine 1, is in a state where the movable side mold 2 is in pressure contact with the fixed side mold 3 (this work process is called the mold clamping process), and the molding material is passed through the conduit 4. After being molded by injection, the movable mold 2 is moved back and away from the fixed mold 3 along the guide 5 (this process is called the mold opening process), and then the movable mold 2 is By protruding a pin (not shown) that protrudes from the rear (this work process is called the protruding process),
It is designed to include the basic work process of dropping the injection molded product below the injection molding machine 1.

However, when the movable mold 2 retreats to open the mold, the product does not fall completely and sticks to the movable mold 2 or the fixed mold 3 even though it should fall. In the next injection molding cycle, the movable side mold 2 advances toward the stationary side mold 3 and presses against it, and the product is clamped between the molds 2 and 3, so that the mold 2 and 3 may be damaged. A monitoring device 6 is provided to prevent such a possibility.

The monitoring device 6 is composed of a video camera 7 and an object detection circuit 8. The video camera 7 is disposed near the movable mold 2 on the side of the injection molding machine 1, and captures images of the mold 2 and its surroundings at the timing when the movable mold 2 has finished opening from the fixed mold 3. The video signal VD is sent to the object detection circuit 8.

Here, the injection molding machine 1 opens the mold 2 after injecting the molding material, and by protruding an ejecting pin provided on the mold 2 side, the product attached to the mold 2 is caused to fall out. . The injection molding machine 1 is sequentially controlled by a sequencer (not shown), and therefore the sequencer sends a command signal S1 as necessary at timings such as when the mold starts to open, when it finishes opening, when the ejector pin ejects, etc. It is designed to send out.

In the case of this embodiment, the video signal VD captured when the mold 2 has finished opening and the product is still attached to the mold 2 (i.e., after the mold opening process and before the ejection process) is sent to the object detection circuit 8. The object detection circuit 8 is configured to be able to capture a video signal VD captured at the timing when the product is captured and then pushed down by the ejection pin (that is, in a state after the ejection process).

As shown in FIG. 2, the object detection circuit 8 receives a standard television video signal including horizontal and vertical synchronization signals sent from the video camera 7.
It has a hold device 11 for receiving VD, and
It has a synchronization signal generator 12 that receives the synchronization signal SY as a trigger signal. Synchronous signal generator 1
2 is a clock signal CL for synchronizing the operation in the object detection circuit 8 with the video camera 7, and a synchronization signal SY.
It is designed to occur in synchronization with the

The hold device 11 stores the luminance signal of a unit area at a plurality of predetermined points, for example, two points, as an analog integral value, out of the image information formed by the video signal VD. If A1 and A2 are expressed by taking the x coordinate in the H direction and the y coordinate in the V direction as shown in Figure 3, they are: point (x ₁ , y ₁ ), point (x ₁ +m, y ₁ ), point (x ₁ ,
y ₁ +n), point (x ₁ +m, y ₁ +n), and the monitoring area A2 is surrounded by the point (x ₂ , y ₂ ),
Point (x ₂ + m, y ₂ ), point (x ₂ , y ₂ + n), point (x ₂ +
It consists of an area surrounded by four points (m, y ₂ +n).

As shown in FIG. 4, the hold device 11 has first and second analog integration circuits 16A and 16B corresponding to first and second areas A1 and A2 which receive the video signal VD through the buffer circuit 15. The first analog integration circuit 16A converts the incoming video signal VD into a current through an analog switch 18A in a voltage-current conversion circuit 19A, and then applies the converted current to an integration capacitor 20A. The analog integrated value thus accumulated in the capacitor 20A is sent out as the first hold signal S2A through the buffer circuit 21A. Further, the hold voltage of the capacitor 20A is cleared through a clearing analog switch 22A connected in parallel.

On the other hand, the second analog integration circuit 16B also passes the incoming video signal VD to the voltage-current conversion circuit 1 through the hold analog switch 18B.
After converting into current at 9B, the integration is held in the integrating capacitor 20B, and the hold value is sent to the second hold signal S2 through the buffer circuit 21B.
Send as B. In this case as well, capacitor 20B
A clearing analog switch 22B is connected in parallel to the clearing analog switch 22B.

The hold analog switches 18A and 18B and the clear analog switches 22A and 22B of the analog integration circuits 16A and 16B are turned on by the acquisition signal S3I and clear signal S3C generated by the timing generator 25 (FIG. 2), respectively. be done.

That is, as shown in FIG. 5, the timing generator 25 generates the starting point of the vertical synchronization signal V (FIG. 5A)
The acquisition signal S3I is generated at timings corresponding to the monitoring areas A1 and A2 for the scanning lines that cross the monitoring areas A1 and A2 among the first, second, . . . th scanning lines starting from _t0 . Third
In the case of the embodiment shown in the figure, the monitoring area A1 is a horizontal synchronizing signal for the lines from the y _- th line (By ₁ in FIG. 5) to the (y ₁ +n)-th line (B(y ₁ +n) in FIG. 5). When the time corresponding to the coordinate x ₁ in the x-axis direction has elapsed from the start point of Hy ₁ to H (y ₁ + n), the capture timing signal TA1 is sent for a time corresponding to the distance m in the x-axis direction of the monitoring area A1. Also, for monitoring area A2, from the y _2nd line to the y ₂
Each horizontal synchronizing signal Hy _{2 to} H(y ₂
+n) When a timing corresponding to the coordinate x ₂ of the monitoring area A2 has elapsed from the rising edge of the signal TB, the capture timing signal TB is sent to the analog switch 18B.
1 for a time corresponding to the distance m in the x-axis direction of the monitoring area A2.

Thus, in FIG. 3, the analog switches 18A and 18B are turned on at the timing when the scanning line scans the monitoring areas A1 and A2 for one field worth of video signal, so that the video signal corresponding to the optical energy of the monitoring areas A1 and A2 is turned on. The integrated value of the signal is held in capacitors 20A and 20B for each corresponding line.

The analog integrated values held in the analog integration circuits 16A and 16B are cleared by a clear signal S3C sent from the timing generator 25 at the timing of the vertical synchronization signal V that arrives at the start of each field.
is cleared by turning on the clearing analog switches 22A and 22B, thereby obtaining an analog integrated amount representing the optical energy of the video signal corresponding to the monitoring areas A1 and A2 for each field.

In this way, the analog integrated output signal S4 consisting of the hold signals S2A and S2B of the hold device 11 is the sampling clock signal S sent out from the timing generator 25 using the field section following the field section in which the hold operation was performed.
5, the data is converted into digital data in an analog-to-digital converter 26, and this is provided as measurement result data to a reference value calculation device 27 and a comparison/judgment device 28.

The reference value calculation device 27 uses the measurement result data S currently obtained from the analog-to-digital conversion device 26.
6, the judgment reference value data is calculated so that it can be judged based on past measurement result data whether or not there is a product remaining between the movable side mold 2 and the fixed side mold 3 in the injection molding machine 1. , as shown in FIG. 6, has reference value calculation circuits 27A and 27B corresponding to monitoring areas A1 and A2.

That is, the reference value calculation circuit 27A performs arithmetic processing on the measurement result data S6 sent from the analog-to-digital converter 26 based on the timing control signal S8 given from the timing generator 25. That is, the measurement result data S6 is stored in a plurality of memories M1, for example, k stages, which are cascade-connected to each other.
M2...Memory M1, M2... is given to the first-stage memory M1 of Mk, and the measurement result data S6 that arrives in each injection molding cycle in which the injection molding machine 1 molds products one by one is sequentially shifted.
It is designed to be stored in Mk. As a result, the memories M1 to Mk contain k measurement result data S6 detected in the past k injection molding cycles.
is saved. The measurement result data stored in the memories M1 to Mk is provided to an adder AD1, and the addition result data S9 is provided to a divider 32 as an output of the observation data memory 31.

A constant signal S10 corresponding to the number k of addition data in the observation data memory 31 is given to the divider 32 from the constant setter 30, and the simple average value obtained by dividing the data S9 by the data S10 is given from the divider 32. Average value data S11 representing the average value is sent out. This average value data S11 is the upper limit value circuit 3 having a multiplier configuration.
3 and lower limit value circuit 34, and constant signal S1 given from constant setters 35 and 36, respectively.
Upper limit reference signal S1 obtained by multiplying 2 and S13
4 and a lower limit reference signal S15. Here, the content of the constant signal S12 given to the upper limit circuit 33 is set to r _H (r _H >1), and the content of the constant setting signal S13 given to the lower limit value circuit 34 is set to r _L
(r _L <1). In this way, the upper limit value circuit 33 sends out the upper limit reference signal S14, which is larger than the average value of the past k measurement result data, and the lower limit value circuit 34 sends out the lower limit value reference signal S15, which is smaller than the average value of the past k measurement data. be done.

These reference signals S14 and S15 are given as reference signals to the comparison/judgment device 28 (FIG. 2) and compared with the measurement result data S6 sent from the analog-to-digital converter 26, and the measurement result data S6 is used as the upper limit reference. When the signal is smaller than the signal S14 and larger than the lower limit reference signal S15, the product falls normally from the injection molding machine 1, and the movable side mold 2 and the fixed side mold 3
Object detection signal S2 indicating that there is no object between
It will send 0.

On the other hand, if the measurement result data S6 is larger than the upper limit reference signal S14, it means that the brightness between the movable mold 2 and the fixed mold 3 is brighter than when the product is dropped. Indicates the presence of a product (if its outer surface is fairly bright). On the other hand, if the measurement result data S6 is smaller than the lower limit reference signal S15,
The brightness between the movable side mold 2 and the fixed side mold 3 is darker than when there is no product, which means that there is a product (in this case, the outer surface of the product is quite dark). . In this way, when the injection molding machine 1 opens the mold, that is, after the mold opening process, and at the timing when the ejecting process in which the product is dropped by the ejecting pin starts, the product falls into the molds 2 and 3.
It is possible to obtain an object detection signal S20 indicating whether or not there is an object in between.

Further, the reference value calculation circuit 27B is the reference value calculation circuit 2.
It has the same configuration as 7A.

In this way, the presence or absence of an object is detected in each of the monitoring areas A1 and A2, and the reference signal S14A is generated.
, S14B, S15A and S15B are formed, and this is the reference signal S14 of the reference value calculation device 27.
and S15.

In the above configuration, after the injection molding machine 1 finishes molding one product and opens the movable mold 2 to the fixed mold 3 in the mold opening process, the product is pushed out by the ejecting pin in the emptying process. When the detection command signal S1 arrives at the timing generator 25 from the sequencer of the injection molding machine 1 at the timing of time t1 after the injection molding machine ₁ as shown in FIG. 7A (FIG. 2),
The timing generator 25 is the synchronizing signal generator 12
Based on the clock signal CL sent from
As shown in FIG. 7B, a data acquisition signal DT _IN (FIG. 7D) corresponding to the following one field section is formed at time _t2 when the first vertical synchronizing signal V arrives, and at the rising edge of the data acquisition signal DT IN (FIG. 7D). Using the thus formed clear signal S31, the clear switches 22A and 22B of the first and second analog integration circuits 16A and 16B (FIG. 4) of the hold device 11 are turned on to adjust the hold voltage of the capacitors 20A and 20B. and thus the hold signal S2
A and S2B (C1 and C2 in FIG. 7) are once cleared to black level.

Thereafter, the timing generator 25 generates a data acquisition signal TA corresponding to the monitoring areas A1 and A2 (FIG. 3) during the period of the data acquisition signal DT _IN (FIG. 7D).
1 and TB1 (E1 and E2 in FIG. 7) and in response to this, the analog integrating circuit 1
Analog switch 1 of 6A and 16B (Figure 4)
Capacitors 20A and 2 through 8A and 18B
0B is made to integrate and hold the sampling video signal. Thus, the hold signals S2A and S2 of the first and second analog integration circuits 16A and 16B
B is at time t ₂ as shown in FIG. 7 C1 and C2.
After being once cleared to the black level, it rises each time the acquisition signals TA1 and TB1 (E1 and E2 in FIG. 7 are applied).

If the injection molding machine 1 is operating normally and the product is correctly dropped by the ejector pin, the levels of the hold signals S2A and S2B are based on the upper limit values obtained in the reference value calculation circuits 27A and 27B (Fig. 6). Since the level is intermediate between the signal S14 and the lower limit reference signal S15, the comparison/judgment device 28 detects the object detection signal S20 (second
(Fig.) will be transmitted.

On the other hand, if the product does not fall from the movable mold 2 even though the injection molding machine 1 operates the ejector pin, the removal procedure is as shown in FIG. 8 corresponding to FIG. including signals TA1 and TB1 (8th
Video signal when given Figures E1 and E2)
Since the surface of the product is quite bright, the level of the video signal VD increases. Therefore, the levels of the hold signals S2A and S2B sent out from the first and second analog integration circuits 16A and 16B (FIG. 4) of the hold device 11 are equal to the upper limit reference signal obtained in the reference value calculation circuits 27A and 27B. It is larger than S14A and S14B.
(Figure 8 C1 and C2). Therefore, at this time, the comparison/judgment device 28 sends out an object detection signal S20 indicating that an object is present.

In addition, in the above case, the brightness of the surface of the product was described, but conversely, when the surface of the product is darker than when there is no product (for example, when the surface of the product is black), the brightness of the surface of the product is bright. 8 Figures C1 and C2
The levels of the hold signals S2A and S2B shown in FIG. Therefore, in this case as well, the comparison/judgment device 28 sends out the object detection signal S20 indicating that the product has not fallen from the injection molding machine 1.

By the way, such object detection operation is sent from the sequencer every time one product is manufactured in the subsequent injection molding cycle after the injection molding machine 1 closes the movable mold 2 in the mold clamping process and completes one injection molding cycle. The measurement result data S6 sent from the analog-to-digital converter 26 every cycle is sequentially given to the reference value calculation device 27 by the command signal S1 that comes from the analog-to-digital conversion device 26, and at this time, the reference value calculation device 27 is connected to the reference value calculation circuit 27A. The data that arrives sequentially in the memories M1, M2, M3, . Therefore, the magnitude of the video signal when the product falls during the past k injection molding cycles is stored in the reference value calculation device 27, and the upper limit value reference signal S14 and the lower limit value reference signal S15 are calculated based on this data. become.

As a result, if the imaging conditions for the injection molding machine 1 by the camera 7 change during the process, for example due to deterioration of the light source or temperature characteristics, the video signal VD
When the level of the reference value calculation device 27 drifts, the influence appears as a level change in the measurement result data S6 as a fluctuation in the signal level at the measurement input side of the comparison/judgment device 28. Since the levels of the value signals S14 and S15 also fluctuate with the same tendency, the fluctuation components are canceled in the determination operation of the comparison and determination device 28, so that the object detection signal S20
Therefore, the determination operation can be stabilized.

As described above, according to the configuration shown in FIG. 2, in the injection molding machine 1, at the timing when the ejection process is completed, the movable side It is possible to reliably detect whether or not the injection-molded product remains in the mold 2, and thus the determination result is not affected by the drift of the video signal VD due to fluctuations in the imaging conditions. Obtainable.

In the embodiment shown in FIG. 2, the timing generator 25
is a take-in signal generation circuit 41 configured as shown in FIG.
It is equipped with In FIG. 9, the acquisition signal generation circuit 41 has a monitoring position designation memory 42 having a RAM configuration, and data regarding the scanning positions of the monitoring areas A1 and A2 described above with reference to FIG. 3 is written in advance in this monitoring position designation memory 42. Data signals from the main controller (not shown) through circuit 40
It is written as DP. For example, as shown in FIGS. 10 and 11, the monitoring areas A1 and A2 described above in FIG.
Assuming that the length of the scanning line of a book is used to monitor an area having five positions in the H direction, the monitoring position designation memory 42 stores line numbers for the monitoring area A1 as shown in FIG. data y ₁
~y ₁ +3 stores data containing x-direction position data x ₁ and integral circuit designation data [16A], and stores x-direction position data corresponding to line number data y ₂ ~y ₂ +3 regarding monitoring area A2. x ₂ and integral circuit designation data [16B] are stored. Each line number data y ₁ ~ y ₁ +
3, y ₂ to _{y 2} +3 are allocated to a predetermined memory area of the memory 42, and by reading the address of the memory area, the x-direction position data and integral circuit designation data corresponding to the line number data allocated thereto can be obtained. Read out.

The monitoring position designation memory 42 receives y as a read signal.
The count contents of the counter 43 are the address converter 4
4 to the memory 42. The y counter 43 receives a clock pulse provided from the synchronization signal generator 12 (FIG. 2) in synchronization with the horizontal synchronization signal H.
CLH is counted, and thus the contents of the y counter 43 are sequentially designated as scanning line numbers of the video signal VD. The contents of the y counter 43 during operation are y ₁ to y ₁ +3 or y ₂ to _{y 2}
If it becomes +3, the x-direction position data and integral circuit designation data related to the corresponding line number data are stored in the memory 42, so these are
It is read out to the direction position register 45 and the integral circuit designation register 46. The contents of the x-direction position register 45 are given to a comparator 47 and monitored to see if they match the contents of the x counter 48. The x counter 48 is configured to sequentially designate the number of monitoring points in the x direction.
2 (FIG. 2) is divided by a predetermined number to count the clock signal CLx.

When the position is detected by the comparator 47 in this way, the position detection output PS is given as a trigger signal to the pulse generation circuit 49 having a mono-multivibrator configuration, for example, so that a pulse with a predetermined pulse width is sent to the acquisition signal generation circuit having a decoder configuration. 5
0 as a load signal. The acquisition signal generation circuit 50 converts the integration circuit designation data stored in the integration circuit designation register 46 into a line signal.
This signal is converted into SW1 or SW2 and sent as an ON control signal to analog switches 18A and 18B of analog integration circuits 16A and 16B (FIG. 4).

According to the configuration shown in FIG. 9, the monitoring position designation memory 4
2 is x at the left end of the monitoring areas A1 and A2, as is clear from FIGS. 10, 11, and 12.
The direction position data is stored together with the corresponding integration circuit designation data, and thus, when the video signal reaches a section corresponding to a scanning line that crosses the left end of the monitoring area A1 or A2, the contents of the y counter 43 at this time are stored. In accordance with
6, and at the same time, the contents of the x counter 48 for the relevant scanning line are counted so as to sequentially scan the relevant scanning line from the left to the right. When the contents of the x-counter 48 eventually match the contents read to the x-direction position register 45, this means that the video signal of the portion of the video signal VD corresponding to the left end of the monitoring areas A1 and A2 has arrived. means that At this time, the comparator 47 generates a coincidence output PS, so the acquisition signal generation circuit 5
A capture designation signal whose value 0 corresponds to the content of the integration circuit designation register 46 is sent to the analog integration circuits 16A and 16.
It will be sent to B. Here, since the pulse width of the pulse generation circuit 49 is selected to be a length corresponding to the length of the monitoring areas A1 and A2 in the x direction, the generation time of the acquisition signal output from the acquisition signal generation circuit 50 is This means that the time exactly coincides with the time when the monitoring areas A1 and A2 are being scanned.

Therefore, as described above with respect to FIGS. 7 and 8, the acquisition signals TA1 and TB1 (E1 and E2 in FIG. 7, E1 and E2 in FIG. 8) for the four scan lines crossing the monitoring areas A1 and A2 are As a result, the analog integration circuit 16A
and 16B, the integrated values of the video signals corresponding to the monitoring areas A1 and A2 are held as information representing the optical energies of the monitoring areas A1 and A2, and are compared with a reference value, thereby making it possible to easily obtain a determination result. can.

Therefore, if the configuration is as shown in FIG. 9, a relatively simple configuration is required for determining the arrival of the video signal VD corresponding to the monitoring area. Incidentally, it is only necessary to store data regarding the start position of the monitoring area as the data in the monitoring position designation memory 42, and therefore, even if the number of monitoring areas increases, the storage capacity of the memory 42 does not need to be increased that much. Also good. Further, when changing the designation of the monitoring position or the area of the monitoring area, it is only necessary to change the data stored in the monitoring position memory 42, thus realizing a highly versatile injection molding machine monitoring device.

In the embodiments shown in FIGS. 10 to 12, the case where the monitoring areas A1 and A2 do not overlap on the same scanning line has been described, but it is also possible to set multiple monitoring areas so that they overlap on the same scanning line. In this case, as indicated by the dotted line in FIG. Corresponding x-direction position data and integrating circuit designation data may also be specified. Furthermore, the comparator 47 may be provided with not only the contents of the x counter 48 but also the contents of the y counter 43 as a comparison input as necessary. Of course, the number of monitoring areas is not limited to two as in the above embodiment, but can be three or more, or conversely can be one.

Furthermore, in the above description, a case has been described in which a specific area is designated for monitoring the video screen, but instead of this, as shown in FIG. You can also do it. In this case, in FIG. 12, for example, 1
It is sufficient to store the x-direction position data and integral circuit stability data for only one line (in the case of FIG. 12, there are multiple lines). Even in this case, the determination result can be easily obtained using the detection output representing the optical energy of the monitoring area in the same manner as described above regarding the monitoring area.

In this specification, the monitoring area includes the monitoring target along the scanning line as shown in FIG. 13.

FIG. 14 shows another embodiment of the reference value calculation device 27, and as shown by assigning the same reference numerals to the corresponding parts as in FIG.
In the case of Fig. 6, the reference value is obtained at the timing after the movable mold 2 of the injection molding machine 1 moves in the mold opening process and after the manufactured product is dropped by the ejection pin in the ejection process. However, in the case of Fig. 14, in addition to this, the reference value is calculated at the timing before the product is dropped by the ejector pin. It is characterized by the fact that it is done.

That is, the reference value calculation device 27 in the case of FIG.
includes a pre-observation data memory 55 having the same configuration as the observation data memory 31, a divider 56 similar to the divider 32, and a constant setter 57 similar to the constant setter 30. Here, observation data memory 31
The measurement result data S6 is input to the pre-observation data memory 55 via the changeover switch circuit 58.

This changeover switch 58 is controlled by a changeover control signal S21 given from the sequencer of the injection molding machine 1, and the switch 58 is switched to the pre-observation data memory after the injection molding machine 1 has finished opening the movable mold 2. 55 side, the measurement result data S6 is inputted to the front observation data memory 55 side through the switch circuit 58, and the measurement result data S6 is input at the timing after the ejecting operation is performed and the product is dropped. It is designed to be input into an observation data memory 31.

Thus, in the ejecting process, the observation data before and after the ejecting operation of the ejector pin are stored in the memories 31 and 55, respectively, and the simple average value of the data is calculated by the dividers 32 and 56, and the calculation result is calculated by the adder 60 and the divider 61. After performing a simple average calculation, it is sent to the comparison/judgment device 28 as a reference signal S25. In addition, the outputs of the dividers 32 and 56 are given to a comparator 62, and the comparator 62 detects a change between the calculated data before the ejection operation of the injection molding machine 1 and the calculated data after the ejected operation, and makes a comparative judgment. It is sent out as a reference value signal S26 to the device 28.

In the configuration of FIG. 14, the reference value calculation device 27
can store observation data before and after the ejection operation of the injection molding machine 1 in observation data memories 31 and 55, respectively. However, the data before the ejection operation shows that the product manufactured by injection molding machine 1 is still in the movable mold 2.
This data represents the brightness of the outer surface of the product. On the other hand, the data stored in the observation data memory 31 after ejection is the injection molding machine 1.
This is data when the product was dropped from
Therefore, if the injection molding machine 1 is operating normally, the data in the observation data memory 31 will represent the brightness of the injection molding machine 1 when there is no product.

Therefore, the reference value signal S25 obtained by the simple average calculation in the divider 61 represents the intermediate value between when there is a product in the injection molding machine 1 and when there is no product in the injection molding machine 1. The given measurement result data S6 is definitely the reference value S25.
A clear judgment can be made as to whether the standard value S25 is exceeded or not, depending on whether the product is present or not. Therefore, the standard value S2
5, even if there are drifts of the light source, camera, etc., these drifts can be canceled during the judgment operation of the comparison judgment device 28 by forming a reference value that includes them, so that the object detection signal S2
0 can prevent the effect of drift from occurring.

In addition, since the comparator 62 compares the measured data when the product is present and the measured data when the product is not present, it can be determined whether the product is present or not regardless of whether the surface color of the product is black or white. can be done reliably.

Incidentally, if the product is black, the level of observation data when the product is present will be low, whereas if the product falls and disappears, there will be no black object, so the level of observation data when the product is absent will be lower. is higher than when it exists. Therefore, if there is a change in the level of the signal arriving at the comparator 62, the injection molding machine 1 outputs a reference signal S that reliably indicates that the product is no longer present due to the ejecting operation of the ejector pin.
26 can be sent. Conversely, when the product is white, the level of observation data when there is a product is higher than the level of observation data when there is no product. It can be reliably determined that there is no product in the injection molding machine 1. Also in this case, it is possible to prevent the influence of drift from occurring on the determination result in the comparison and determination device 28.

In the configuration shown in FIG. 14, the timing generator 25 (FIG. 2) generates a signal at a time t before the ejector pin performs the ejecting operation, as shown in FIG. 15A, based on a command from the sequencer of the injection molding machine 1. ₁₁ , the calculation command S81 is received, and at the time _t21 after the ejection operation, the calculation command S82 is received again. Upon receiving the calculation commands S81 and S82 in this way, the reference value calculation device 27 calculates the calculation command S81 and S82 as shown in FIG. 15 corresponding to FIG.
81, as shown in FIG. 15 C1 and C2, high-level hold signals S2A and S2B are obtained as a result of integration in the analog integration circuits 16A and 16B in a certain state of the product, and these are the pre-observation signals. The data is stored in the data memory 55.

On the other hand, when the calculation command S82 is obtained, the analog integration circuits 16A and 16B receive a low-level video signal representing a state in which there is no product, so as shown in FIG. 15 C1 and C2, Low level hold signals S2A and S2B are obtained and stored in observation data memory 31.
Therefore, the level of the operation result data obtained from the divider 56 is high, whereas the operation result data obtained from the divider 32 is at a low level.

This operation is a normal operation, but if an abnormality occurs and a product remains in the injection molding machine 1, the level of data stored in the observation data memory 31 becomes high, and the level of the data stored in the observation data memory 31 increases. The output level becomes approximately equal to that of the divider 56.

FIG. 16 shows yet another embodiment of the reference value calculation device 27. That is, in FIGS. 6 and 14, the configuration of observation data memories 31 and 55 is
It is replaced with the observation data memory 65 shown in FIG. The observation data memory 65 is a memory M, as shown by attaching the same reference numerals to the corresponding parts in FIGS. 6 and 14.
1, M2...The output of Mk is set by weight setters W1, W2
... Wk's weighted outputs w ₁ , w ₂ ...w _k are applied as coefficient inputs to the adder AD1 through multipliers PL1, PL2 ... PLk.

With the configuration shown in Fig. 16, when obtaining reference data based on k pieces of past data, it is possible to obtain optimal data as a reference value by weighting each data according to its importance. can. For example, if the background brightness of the injection molding machine 1 changes over time, newer observation data is considered to be more effective data, so the weighting set values w ₁ , w ₂ ... w _k is w ₁ > w ₂ ……
By setting the relationship > _wk , it is possible to prevent errors due to changes in background brightness from appearing in the determination results of the comparison and determination device 28.

In the case of the embodiment shown in FIG. 2, the hold device 11
holds the video signal as an analog value, and converts the hold signal into an analog-to-digital converter 2.
6, the comparison and determination device 28 digitally determines the presence or absence of the object.
As shown in FIG. 7, the analog hold signal obtained in the hold device 11 may be directly applied to the comparison and determination device 28, and the comparison and determination device 28 may determine the presence or absence of an object in an analog manner.
In this case, the output S4 of the hold device 11 is converted into a digital signal by the analog-to-digital converter 71 and given to the reference value calculation device 27 as measurement result data, and the reference value signal obtained as a result of calculation in the reference value calculation device 27 is The signal is converted into an analog signal by the digital-to-analog converter 72 and then provided to the comparison/judgment device 28 . Even in this case, the same effect as described above with respect to FIG. 2 can be obtained.

Further, instead of the configuration shown in FIG. 2, the configuration may be changed to one in which digital data is held as the hold device 11, as shown in FIG. i.e. in this case the video signal coming from camera 7
VD is detected in the monitoring areas A1 and A in the integrating circuit 73 according to the input signal S3 of the timing generator 25.
After integrating according to the area of 2 (FIG. 3), the integration result is converted into a digital signal in an analog-to-digital converter 74 and stored in the digital memory 7.
Store in 5. In this way, measurement result data S6 in digital signal format can be obtained from the hold device 11, and therefore, this measurement result data S6 can be directly provided to the reference value calculation device 27 and the comparison/judgment device 28. In this way, the same effect as in the case of FIG. 2 can be obtained.

Furthermore, instead of the configuration of the integrating circuit 73 in FIG. 18, a first
The structure may be changed as shown in FIG. 9. That is, in FIG. 19, the video signal coming from camera 7
VD samples instantaneous values corresponding to positions in the x direction on each line in a sampling circuit 76 and converts them into digital values in an analog-to-digital converter 77, which is then applied to an adder 78. The adder 78 sequentially adds the instantaneous value data arriving at each sample point in the monitoring area, and stores the addition result in the digital memory 79. In this way, the video data sampled over the entire area of the monitoring area is integrated at the output end of the adder 78, thereby making it possible to obtain data substantially similar to integrating an analog signal. In this way, the effect that can be obtained in FIG. 18 can also be obtained with the configuration shown in FIG. 19.

Furthermore, instead of the analog integrating circuits 16A and 16B shown in FIG. 4 as the hold device 11 for holding analog signals, those having the configuration shown in FIG. 20 may be applied. That is, the case of FIG. 20 differs in that a filter circuit 81 is provided in place of the voltage-current conversion circuits 19A and 19B of FIG. Here, the filter circuit 81 is composed of a high-pass filter, and therefore, the DC component contained in the video signal obtained from the camera cannot pass through the filter circuit 81, and as a result, only the video signal is held in the capacitors 20A and 20B. That will happen.
Therefore, it is possible to reduce errors in the determination results due to changes in the DC component. In addition, since the filter circuit 81 limits the frequency of the video signal held in the capacitors 20A and 20B to a specific region, it is possible to remove noise contained in the low frequency band portion.

In addition, in the hold device having the configuration shown in FIG. 4, in order to hold a plurality of sample signals, an analog memory consisting of capacitors 40A and 40B is connected in parallel via input analog switches 18A and 18B, but instead of this, , 21st
As shown in the figure, the video signals obtained through the buffer circuit 15 are transferred to analog switches 82 and 82 respectively.
Analog memories 83A, 83B... which are cascade-connected to each other through A, 82B...82(N-1).
83N, and each analog memory 83
Measurement output signals corresponding to each monitoring point S31A, S31B...S31 in parallel from A, 83B...83N
It is also possible to send out N.

Furthermore, as shown in FIG. 22, in the configuration shown in FIG. 21, if the measurement output signal is sent only from the final stage analog memory 83N, the output signal S32 obtained in this way will be the measurement signal corresponding to each monitoring point. This means that it can be transmitted in a time-series manner. Even in this case, the same effect as described above with respect to FIG. 4 can be obtained.

Furthermore, in the above-described embodiment, the synchronizing signal is given from the camera 7 to the synchronizing signal generating device 12, but instead of this, the synchronizing signal generating device 12
The camera 7 may be synchronized with the synchronization signal generated in the above.

As described above, according to the present invention, based on the timing command signal given from the injection molding machine, an image of the monitoring position where the injection molded product should be at the timing when the mold opening process ends and the ejection process starts, and the ejection By comparing the image of the monitoring position at the timing at which the process ends, it is possible to reliably determine whether or not the product has been pushed down in the ejection process. In making such a determination, the light energy in the monitoring area is detected by integrating the video signal corresponding to the monitoring area, and the detection result is compared with a reference value, thereby making it possible to further reduce noise. In addition, unlike the conventional case, it is not necessary to reproduce the screen on the cathode ray tube once, so the overall configuration can be made smaller and the measurement work does not become complicated, and it is possible to prevent operational errors and screen errors. It is possible to easily obtain a monitoring device for an injection molding machine in which there is no possibility of errors occurring due to light entering the sensor to be disposed on the surface.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view showing an overview of the injection molding machine monitoring device according to the present invention, FIG. 2 is a block diagram showing the detailed configuration of the object detection circuit, and FIG. 3 is a schematic diagram for explaining the monitoring area. 4 is a connection diagram showing the detailed configuration of the hold device 11 in FIG. 2, FIG. 6 is a block diagram showing the specific configuration of the reference value calculation device 27 in FIG. 2, FIGS. 7 and 8 are signal waveform diagrams showing signals of each part in FIG. 2, and FIG. 10 is a block diagram showing details of the acquisition signal generation circuit 41 included in the timing generation device 25.
12 are schematic diagrams and charts for explaining the configuration of FIG. 9, FIG. 13 is a schematic diagram showing another embodiment of the monitoring area, and FIG. 14 is the reference value calculation device of FIG. 2. 15 is a signal waveform diagram for explaining its operation. FIG. 16 is a block diagram showing still another embodiment of the reference value calculation device 27 of FIG. 2. 17 to 19 are block diagrams showing still other embodiments of the holding device 11 of FIG. 2, FIG. 20 is a connection diagram showing another embodiment of the holding device 11 of FIG. 2, and FIGS. 3 is a block diagram showing still another embodiment of the holding device 11 of FIG. 2. FIG. 1... Injection molding machine, 2, 3... Movable side, fixed side mold, 7... Video camera, 8... Object detection circuit,
DESCRIPTION OF SYMBOLS 11... Hold device, 12... Synchronization signal generator, 25... Timing generator, 26... Analog-to-digital converter, 27... Reference value calculation device, 28... Comparison/judgment device, 41... Capture signal generation circuit.

Claims (1)

[Claims] 1. A first step of injecting the molding material with the mold closed, a second step of opening the mold after injection molding, and ejecting the product molded by the mold. In a monitoring device for an injection molding machine that monitors an abnormality in an injection molding cycle that includes a third step of taking out the injection molding machine as a work step, (a) a working state around the mold of the injection molding machine during the injection molding cycle; (b) a video camera that receives a timing command signal from the injection molding machine indicating the progress of a work process included in the injection molding cycle, and sends out a video from the video camera based on the timing command signal; Of the signal, a video signal portion corresponding to a monitoring area having a predetermined size at a predetermined monitoring position in the image information represented by the video signal is captured, and a level corresponding to the integral value of the captured video signal is captured. (c) comparing the level of the detection result signal output from the detection means with a reference value set for each of the monitoring areas, and determining the injection rate in the work process; 1. A monitoring device for an injection molding machine, comprising: comparison and determination means for determining whether or not the operation of the molding machine is normal, and transmitting a determination signal representing the determination result. 2. The injection molding machine monitoring device according to claim 1, wherein the reference value is obtained by calculation in a reference value calculation means based on the detection result signal of the detection means. 3. The injection molding machine according to claim 2, wherein the reference value calculation means calculates the reference value based on the levels of the plurality of past detection result signals for each monitoring position. monitoring equipment.