JP2884385B2 - Method and apparatus for monitoring molded articles of an injection molding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molded article monitoring method and apparatus for monitoring the quality of molded articles in an injection molding machine.

[0002]

2. Description of the Related Art Normally, in an injection molding machine, before starting mass production, molding is performed on a trial basis, molding conditions are determined, and then a transition is made to a continuous operation for mass production. The probability of occurrence of defects in the molded product is small. However, when the injection molding machine is operated for a long time, a change in the molding state may occur due to a temporal change of the injection molding machine itself, an environmental change such as an ambient temperature, or the like, and a sign of a defective product may appear.

On the other hand, conventionally, in order to grasp a change in a molding state, monitoring data and process data of all shots after a shift to a continuous operation are displayed or printed, or stored in an external storage device. It is common to do.

[0004] The monitoring data is, among the data used for controlling the injection molding machine, data obtained only at one point in one shot, for example, the start point and end point timing of one shot, the minimum cushion position, and the like. It indicates data such as the resin filling peak pressure, and the process data refers to data obtained continuously during one shot in addition to the above monitoring data, for example, data such as injection speed, injection pressure, screw position, etc. I do.

[0005]

However, such a method requires a huge amount of data and requires a large-capacity external storage device. In addition, the pass / fail judgment is also performed by reading data once stored in the external storage device, so there is a time lag from the collection of monitoring data and process data until the pass / fail judgment result is obtained. There is a problem that it cannot be effectively dealt with when a defect occurs.

In view of the above problems, an object of the present invention is to provide a method and an apparatus for monitoring a molded article capable of collecting process data for ensuring the quality of the molded article without using a large-capacity external storage device. Is to do.

[0007]

According to the present invention, a plurality of types of process data indicating the injection speed, injection pressure, screw position, etc. from various sensors provided in an injection molding machine are converted into digital data, The data is extracted, and one of each of these multiple types of digital data is extracted.
An analog waveform indicating a change in a shot is generated, and the plurality of types of result data and the analog waveform are stored in a temporary storage unit for several shots while updating the analog waveform in a first-in first-out manner. The result data of the type and the analog waveform are stored in the storage unit for several shots, and at least one of the plurality of types of result data is compared with a preset reference value for each shot to determine the quality of the molded product. ,
When it is determined that a defect has occurred, a method for monitoring a molded article of an injection molding machine is characterized in that the actual data and the analog waveform for several shots stored in the temporary storage unit are stored in the storage unit.

According to the present invention, a plurality of types of process data indicating an injection speed, an injection pressure, a screw position, and the like from various sensors provided in an injection molding machine are converted into digital data, and actual data is extracted. Signal processing means for generating an analog waveform indicating a change within one shot from each of the plurality of types of digital data, and temporarily storing the plurality of types of result data and the analog waveform for several shots while updating the first-in first-out method A temporary storage unit, a storage unit for storing the plurality of types of result data and the analog waveform for several shots at a predetermined time interval, and setting for setting a reference value for the plurality of types of result data Means,
At least one of the plurality of types of performance data is compared with a set value set by the setting unit for each shot to determine whether the molded product is good or bad. When it is determined that a defect has occurred, the contents of the temporary storage unit are determined. A molded article monitoring device for an injection molding machine, comprising: a quality judgment unit to be stored in the storage unit; and a display unit for displaying the performance data, the analog waveform, and the like.

[0009]

According to the present invention, the change of the molding state in the injection molding machine is mainly caused by the time variation of 24 hours a day such as morning, noon and night, and the necessary data is stored. Is performed for a few shots at regular time intervals. In addition, monitoring data and process data from the injection molding machine are collected and processed in real time, and pass / fail judgments using these data are also made in real time. When a defect occurs, necessary data for several shots before and after that is stored. I try to make it.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. Referring to FIG. 1, a molded article monitoring device 10 according to the present invention is connected to an injection molding machine main body 20 via a signal line in this case.
0 may be incorporated. Here, as signal lines, signal lines 31, 32, and 33 are shown as typical examples for supplying process data. Signal line 31
Speaking of these, there are a plurality of signal lines for supplying detection signals (analog signals) of various sensors (for example, sensors for injection speed, injection pressure, screw position, etc.) used for molding control to the molded article monitoring apparatus 10. The signal line 32 is used for monitoring data used in the injection molding machine main body 20, for example, 1
Signal lines for supplying signals indicating the start point timing and the end point timing of the shot from the control device 21 in the injection molding machine main body 20 to the molded article monitoring device 10. The signal line 33 is a signal line for supplying a signal indicating a set value set by the setting device 11 provided in the molded article monitoring device 10 to the control device 21. Although not shown, it goes without saying that the various sensors are actually connected to the control device 21 as well.

The molded article monitoring apparatus 10 has a setting unit 11, a signal processing unit 12, a temporary storage unit 13, a pass / fail judgment unit 14, a storage unit 15, and a display unit 16 such as a CRT or LCD. The setting unit 11 sets a value to be obtained at a certain time in one shot corresponding to each of a plurality of types of process data. For example, with respect to the injection speed, a set value (time data, time data, etc.) is set such that the start point of one shot is used as a reference point, the speed v1 at time t1, and the speed v2 at time t2.
Speed data) is input. These set values are supplied to the control device 21 and also input to the signal processing unit 12 and the pass / fail determination unit 14.

The signal processing unit 12 includes an A / D converter and a CPU.
After converting a plurality of types of analog signals from the signal line 31, that is, process data into digital signals, the setting unit 11 sets each of the plurality of types of digital signals for one shot. The level is calculated in synchronization with the time data, which is digitized as actual data and temporarily stored in the internal memory. The signal processing unit 12 also samples a plurality of types of digital signals at a fixed period (for example, 100 points in one shot), generates analog waveforms indicating time-series level changes in one shot, and generates an analog waveform. To be stored temporarily. When the analog waveform is generated, the start point and the end point of the analog waveform are defined by signals indicating the start point and the end point timing of one shot in the monitoring data output from the control device 21. The result data and the analog waveform stored in the internal memory are sequentially supplied to the temporary storage unit 13 and the pass / fail determination unit 14.

The temporary storage unit 13 is a so-called FIF
This is an O-type storage device, and has a capacity to store a plurality of shots (for example, 5 shots) of the actual data and the data indicating the analog waveform supplied from the signal processing unit 12 for each shot. , The oldest one shot of data is output to the storage unit 15.

The pass / fail judgment unit 14 receives a plurality of types of actual data from the signal processing unit 12 for each shot, and receives data indicating a set value corresponding to the type of the actual data from the setting unit 11. The pass / fail determination unit 14 also has a CPU and an internal memory, and compares the set value for each type of the performance data. If the difference between the performance data and the set value exceeds a certain range, it is determined that a defect has occurred. The data is discriminated and output to the temporary storage unit 13 and the storage unit 15 as a data transfer signal. The pass / fail determination unit 14 also receives data indicating an analog waveform for one shot from the signal processing unit 12, and outputs a maximum value,
Extract and extract features such as minimum value, rise time (time from rising from a certain level to a certain higher level), falling time (time from falling to a certain level lower than a certain level) The obtained feature amount is output to the storage unit 15.

Normally, the temporary storage unit 13 performs an operation of updating and storing one shot of actual data and data indicating an analog waveform supplied from the signal processing unit 12 as described above. Discrimination unit 14
When receiving the data transfer signal from the storage unit 15, all of the stored actual data and the data indicating the analog waveform for several shots are output to the storage unit 15.

On the other hand, the storage unit 15 normally receives the actual data and the data indicating the analog waveform for each shot from the temporary storage unit 13, but actually stores the data at regular intervals, for example, every hour. Only data for shots. However, when a data transfer signal is output from the pass / fail determination unit 14, that is, when a failure is detected, data for several shots output from the temporary storage unit 13 is stored. The storage unit 15 also stores digitized data indicating the feature amount from the pass / fail determination unit 14 according to the display mode set by the setting unit 11. That is, the setting device 11 can specify not only the input of the set value but also the display mode on the display unit 16. Examples of the display mode include an analog waveform display mode for displaying an analog waveform, an analysis list display mode for displaying an analog waveform and numerical result data or a feature amount,
There is a numerical display mode for displaying only numerical result data or feature values.

FIG. 2 shows a display example of the display unit 16 in the analysis list display mode among the above display modes. In FIG. 2, “left end value” and “right end value” respectively indicate the left end and right end positions of an area in which an analog waveform has been analyzed for feature extraction. This is because the pass / fail determination unit 14 can perform analysis on the analog waveform not in the entire area but in a specific range, and this range is set by the setting unit 11.

The data stored in the storage unit 15 may be displayed on the display unit 16 or may be printed out by operating the setting unit 11 as necessary, for example, by connecting a printer or the like. When a plurality of injection molding machines are centrally managed or group-managed by a host computer (not shown), data stored in the storage unit 15 may be transmitted to the host computer.

As an example of the pass / fail judgment in the pass / fail judgment unit 14, the following method can be adopted. That is, the pass / fail determination unit 14 sets an upper limit and a lower limit to the set value set by the setting unit 11 within a range narrower than the above-described predetermined range for pass / fail determination. When the value exceeds the value, it is determined that there is a possibility that a defect may occur, and a signal indicating that fact can be output. According to such a determination method, a measure for avoiding a defect can be taken before a defect actually occurs, which is effective in preventing the occurrence of a defect.

The operation flow will be described below. When the continuous operation for mass production starts, process data from various sensors is collected by the signal processing unit 12 for each shot. The signal processing unit 12 converts the received process data into digital data and, based on the data indicating the set value from the setting unit 11 and the signal indicating the start point and end point of one shot from the control device 21, the actual result for one shot. The data is calculated, an analog waveform is generated, and these data are temporarily stored in an internal memory. The data stored in the internal memory is sequentially supplied to and stored in the temporary storage unit 13, and the pass / fail judgment unit 14 compares the actual data with data indicating a set value from the setting unit 11 to perform a pass / fail judgment operation. At the same time, feature values such as maximum value and minimum value are extracted from the analog waveform. Data indicating this feature amount is temporarily stored in the internal memory.

The above operation is performed for each shot, and the temporary storage unit 13 stores the actual data for several shots and the data indicating the analog waveform while updating each shot. On the other hand, the storage unit 15 stores only a few shots of the actual data and the data indicating the analog waveform paid out by updating from the temporary storage unit 13 at regular intervals, and the analog waveform extracted by the pass / fail determination unit 14. Is stored.
Note that there is a gap of several shots between the data output from the temporary storage unit 13 and the data output from the pass / fail determination unit 14, so that the data of the same shot is stored or read in the storage unit 15. Needless to say, the operation is performed as follows.

Next, when a defect is detected in the pass / fail judgment unit 14 during the continuous operation, a data transfer signal indicating this is output to the temporary storage unit 13 and the storage unit 15. Upon receiving the data transfer signal, the temporary storage unit 13 stores all of the stored actual data for several shots and the data indicating the analog waveform in the storage unit 1.
5 is output. Upon receiving a signal indicating data transfer, storage unit 15 stores data for several shots from temporary storage unit 13. The data stored in the storage unit 15 is displayed on the display unit 16 in a display mode according to the designation of the setting device 11.

As is apparent from the above description, in the present invention, the actual data and the data indicating the analog waveform and the data indicating the characteristic amount of the analog waveform for several shots are stored at regular time intervals. Is much smaller than the conventional method of storing all the data. On the other hand, if data is saved for several shots at regular time intervals, data at the time of failure may be lost.However, in the present invention, data for several shots before and after the failure can be saved even at the time of failure, By analyzing this data, it is possible to know what caused the failure. In addition, changes in the molding state that cause defects are not sudden, and are often influenced by time factors such as morning, noon, and night, so by analyzing data stored at regular time intervals, It is possible to know in advance in what time period the state change is likely to occur, and it is possible to take measures to prevent the occurrence of defects in advance.

[0024]

As described above, according to the present invention, a large-capacity storage device is not required, and the quality can be determined in real time, and the storage timing of the data for monitoring can be designated by the time, so that the quality can be secured. It is ideal for creating daily reports and collecting data unattended.
In addition, if the data is stored at the same time during one day, when the environments are similar, the factor analysis at the time of occurrence of a defect becomes easy and reliable.

[Brief description of the drawings]

FIG. 1 is a diagram showing a connection example of a configuration example of a molded article monitoring device according to the present invention with an injection molding machine main body.

FIG. 2 is a diagram showing a display example displayed on a display unit according to the present invention.

[Explanation of symbols]

 Reference Signs List 10 Molded product monitoring device 20 Injection molding machine main body 31, 32, 33 Signal line

Claims (3)

(57) [Claims] 1. A plurality of types of process data indicating an injection speed, an injection pressure, a screw position, and the like from various sensors provided in an injection molding machine are converted into digital data, and actual data is extracted. An analog waveform indicating a change within one shot is generated from the digital data, and the plurality of types of result data and the analog waveform are stored in the temporary storage unit for several shots while being updated in a first-in first-out manner, while being predetermined. At a time interval, the plurality of types of result data and the analog waveform are stored in the storage unit for several shots, and at least one of the plurality of types of result data is compared with a reference value preset for each shot to form a molded product. Quality is determined, and when it is determined that a defect has occurred, it is stored in the temporary storage unit. A method of monitoring a molded article of an injection molding machine, wherein the actual data and the analog waveform for several shots are stored in the storage unit. 2. A plurality of types of process data indicating injection speed, injection pressure, screw position, etc. from various sensors provided in an injection molding machine are converted into digital data to extract actual data, and the plurality of types of process data are extracted. Signal processing means for generating an analog waveform indicating a change within one shot from digital data, a temporary storage unit for temporarily storing several shots while updating the plurality of types of result data and the analog waveform in a first-in first-out manner; A storage unit that stores the plurality of types of result data and the analog waveform for several shots at a predetermined time interval, setting means for setting a reference value for the plurality of types of result data, At least one of the types of actual data is set by the setting means for each shot. A pass / fail judgment unit for judging the quality of the molded product by comparing the result with the set value, and storing the contents of the temporary storage unit in the storage unit when the occurrence of a defect is judged; And a display unit for displaying the same or the like. 3. The molded article monitoring device according to claim 2, wherein the setting means sets an upper limit value and a lower limit value as the set value, and the pass / fail determination unit determines whether the performance data is the upper limit value or the lower limit value. A molded article monitoring device for an injection molding machine, which also has a function of generating an alarm when the value deviates from a value.