JP3304544B2 - Waveform judgment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waveform judging apparatus suitable for judging the quality of a resin injection pressure waveform of an injection molding machine.

[0002]

2. Description of the Related Art In an injection molding machine or the like, if there is a variation in injection pressure of a molten resin injected into a cavity formed in a mold, a molded product may be uneven.
For this reason, the injection pressure is usually monitored so as to always fall within the standard. At this time, a waveform determination device for the injection pressure may be used to determine whether the injection pressure is good or not.

[0003] The waveform determination device determines a reference injection pressure waveform in advance, measures the actual waveform used in the molding process, and determines whether the measured waveform is within the standard determined from the reference waveform. Device. The injection pressure in the cavity can be measured by a pressure sensor attached to an eject pin for removing a molded product from a mold.

When a plurality of cavities are provided in a mold of an injection molding machine and a resin is injected into each of the cavities to simultaneously mold the same material, the pressure of the resin injected into each cavity varies. Not required. Therefore, when using such an injection molding machine, the balance of the injection pressure to each cavity is measured.

The balance of the injection pressure can be obtained by observing the injection pressure waveforms. The above-described waveform determination apparatus has a function of simultaneously observing such a plurality of measurement waveforms and comparing the two.

FIG. 6 shows an example of a waveform judging device 10 capable of simultaneously observing a plurality of measured waveforms. In this example, a two-input measurement example is shown.

An input signal (reference waveform or measurement waveform signal) supplied to a terminal 12 shown in FIG. 6 is supplied to an input section 14 and adjusted (amplified or attenuated) to a level suitable for conversion into digital data. You. The input signal whose level has been adjusted is converted into digital data of a predetermined number of bits by an A / D converter 16 and then supplied to a data memory 18 for storage.

The input signal whose level has been adjusted is further supplied to a comparator 20, and the rising level of the input signal is compared with a reference level (trigger set value). When the input level is equal to or higher than the trigger level, a comparison output is obtained. . When the comparison output is obtained, the memory controller 22 is controlled by the CPU 24 to control the mode of writing data to the data memory 18.

For example, in synchronization with the timing at which the comparison output is obtained, digital data is written for a predetermined period from this time, or a constant amount of data is constantly updated and stored while the data memory 18 is in the write mode. When the comparison output is obtained, the write mode is prohibited, so that the digital data is written from the timing at which the comparison output was obtained to a period that is a predetermined period earlier. The following description is an example of the former. These mode controls are performed by the CPU 24.

After the waveform data is once stored in the display memory 28, the measured waveform is displayed on a display device (monitor such as a CRT) under the control of the display controller 26.
30 is displayed.

A terminal 32 is an input terminal for another measured waveform, and is supplied to an A / D converter 36 via an input section 34 and converted into a digital signal after being stored in a data memory 38 as described above. You.

The input signal whose level has been adjusted by the input section 34 is also supplied to the above-described comparator 20, which is the same as that for the input signal supplied to the terminal 12. Therefore, a comparison output is obtained based on the earlier input signal which has reached the trigger level among the pair of input signals, and this is used as a trigger to fetch data into the data memories 18 and 38 at the same time.

When the measured waveform is compared with the reference waveform, the received measurement data and the reference data are compared with each other to determine the quality, and the reference waveform and the measurement waveform are graphed and displayed on the display device 30. Displayed at the same time.

In the comparison mode between the measured waveforms, the display device 3
Each waveform is displayed on 0 (see FIG. 9), and the difference between the two waveforms and the quality of the resin injection pressure are determined.

[0015]

The above-described injection molding machine may be constructed such that a plurality of same cavities are formed in one mold and a plurality of same objects are simultaneously molded. The branch length from the main runner of the runner for injecting resin into each cavity is not always the same.

Therefore, a plurality of cavities include a cavity into which the resin is simultaneously injected and a slightly different cavity. When the resin is injected simultaneously, the trigger points (= data fetch timing) for the measured waveforms (input signals) Sa and Sb match as shown in FIGS. 7A and 7B. Data can be captured.

When the resin is not injected at the same time, FIG.
As shown in A and C, the trigger points (trigger timing) slightly differ. This difference in trigger timing results in jitter of the measured waveform, and this causes the data memory 18
The waveform captured in the data memory 38 does not match the waveform captured in the data memory 38. That is, as shown in FIG. 7C, the capturing area differs by ΔT due to the jitter, and therefore, the two cannot be accurately compared.

In the case of FIG. 7, a plurality of measurement waveforms applied to the waveform judgment device 10 are synchronized waveforms. In some cases other than the synchronous input, there is also a case where the determination is made while comparing the two measured waveforms (see the measured waveforms Sc and Sd in FIG. 8).

In the measured waveforms Sd and Sc of FIG. 8, the data area actually required is an area (period) Tc accompanied by a change in the waveform.
(Or Td), the configuration shown in FIG. 6 has the same trigger point in both cases, so that the period Tb more than necessary
(Tb> Tc) must be set as the data acquisition period, and an unnecessary measurement period increases.

As described above, when referring to all the waveforms in the period Tb, it is necessary to prepare large-capacity memories as the data memories 18 and 38. In particular, if the sampling frequency for the measurement waveform is increased to increase the resolution and the number of conversion bits is increased, the memory capacity becomes enormous.

In the case of FIG. 8, since the waveform of an unnecessary area is also displayed on the display device 30 as shown in FIG. 9, the waveform to be observed cannot be enlarged and displayed, and the waveform cannot be accurately observed. Would.

Accordingly, the present invention has been made to solve such a conventional problem and proposes a waveform judging device which can set trigger timings for a plurality of measured waveforms independently and solves the above-mentioned problem. It is.

[0023]

In order to solve the above-mentioned problems, a waveform judging device according to the present invention is a device for inputting a plurality of measured waveforms and comparing and judging respective waveforms .
Input the measured waveform and set the rising level and reference
Level and compare the input signal level of the waveform with the reference level.
Outputs the time that is equal to or higher than the bell as the trigger timing
Comparator and the comparator output
Digital data corresponding to measured waveform in synchronization with rigger timing
Means having a data memory for writing file data
The reference level of each comparator is set to a predetermined value.
And set a predetermined period from each trigger timing.
Digital corresponding to multiple measurement waveforms for the period
Data is taken in each data memory .

[0024]

According to the waveform judgment apparatus of the present invention, a plurality of measurement
When a constant waveform is input and each waveform is compared and judged.
In this case, set the reference level of each comparator to a predetermined value.
And set a predetermined period from each trigger timing.
Is determined. Digital signals corresponding to multiple measurement waveforms only during the period
In order to load data into each data memory.
You. Based on this, each comparator measures
Enter the shape and the rising level and reference level of the waveform
Is compared with From this comparator to data memory
Means that the input signal level of the waveform is higher than the reference level
The time is output as a trigger timing. Each de
Data memory in synchronization with this trigger timing.
Write digital data corresponding to the measured waveform.
Is done. Therefore, the input signal level of the waveform
Measurement using the time that is greater than or equal to
Digital data corresponding to the waveform is stored for each means.
Can be written to memory. That is, when a plurality of measured waveforms are acquired at the same trigger timing and displayed on the display device 30, when it is determined that there is jitter as shown in FIGS. 2A and 2B, the trigger level of the comparator 20 or 40 shown in FIG. Adjust each one independently. This
In this example, the reference level is set to the same value in each comparator.
And set the same period in advance from the trigger timing.
Set it. After such adjustment, the time point ta is selected as the trigger timing for the measurement waveform of FIG. 2A, and the time point tb is selected as the trigger timing for the measurement waveform of FIG. 2B.

In the case of asynchronous input, time points tc and td are set as trigger timings as shown in FIGS. 3A and 3B. Then, only the necessary waveform can be stored in the memory, and only the waveform can be displayed on the display device 30 (see FIG. 4). Since the area of the waveform to be stored is shortened, the memory capacity does not increase as much even if the sampling frequency is increased for higher resolution.

[0026]

Next, a case where an example of a waveform judging device according to the present invention is applied to the above-described injection pressure judgment of an injection molding machine will be described in detail with reference to the drawings.

FIG. 1 is a system diagram showing an example of a waveform judging device according to the present invention. In this example, a two-input measurement example is shown.
The processing system for the input signal corresponding to the measurement waveform supplied to the terminal 12 is the same as that in FIG.

The signal processing system for the input signal at the terminal 32 also has an input section 34, where the level is adjusted and then supplied to an A / D converter 36 to be converted into a digital signal having the same number of bits as described above. And the data is stored in the data memory 38.

The data fetch timing (equivalent to the write timing in this example) is provided independently similarly to the input signal processing system of the terminal 12. Therefore, the level-adjusted input signal is supplied to the comparator 40 and is compared with a trigger level uniquely set. When an input signal of a trigger level or more is supplied, the memory controller 42 operates with the comparison output. Data memory 38
Is instructed to write data.

The trigger level can be set by a resistor 41, but instead of this, a CPU as a control unit
24 can also be set. In that case, the resistor 41 is unnecessary. The comparator 20 is also provided with a resistor 21 for setting a trigger level.
Similarly, the trigger level may be set by the CPU 24.

As described above, since the trigger level can be set independently for each of the processing systems for the two input waveforms, the actual waveform determination processing can be performed as follows.

When a plurality of measured waveforms (input signals) are fetched at the same trigger timing and displayed on the display device 30, when it is determined that there is jitter as shown in FIGS. 2A and 2B, the comparator 20 shown in FIG. Adjust each of the 40 trigger levels independently.

By adjusting the trigger level La, FIG.
Is selected as the trigger timing for the measured waveform Sa. For the measured waveform Sb in FIG. 2B,
The trigger level is adjusted so that it becomes the same trigger level La as in FIG. A, and as a result, the time point tb becomes the trigger timing for the measured waveform Sb.

After the trigger level adjustment, the respective waveform data is taken into the data memories 18 and 38 for the same period Te. By doing so, the waveform data from the same trigger level can be captured for the same period Te for both the measured waveform Sa and the measured waveform Sb, so that the comparison between the two waveforms becomes accurate, and the pass / fail judgment and the like can be performed with accuracy. Can do well.

In the case of asynchronous input, the respective trigger levels Lc are set such that the times tc and td are the respective trigger timings as shown in FIGS. 3A and 3B. Then, necessary waveforms can be stored for the same period Tf. As a result, the region of the waveform to be stored becomes shorter than before, so that even if the sampling frequency is increased in order to increase the resolution, the memory capacity does not increase so much.

Since only necessary waveforms are stored,
Even if the measurement waveform is asynchronous as shown in FIG.
Since only necessary waveforms can be enlarged and displayed, the measured waveform can be accurately observed.

The waveform judging device 10 not only compares and judges a plurality of waveforms described above, but also measures a measured waveform Sa with respect to a reference waveform.
And Sd can be compared and determined.

In order to perform the judgment processing for the reference waveform,
First, an input signal serving as a reference waveform supplied to the terminal 12 is fetched into the data memory 18, a standard range setting program is started for the fetched reference waveform according to an instruction from a keyboard, and a standard range is determined by the CPU 24. The data (upper limit data and lower limit data) is stored in the data memory 18 together with or instead of the reference waveform data.

The extent of the standard range is input from the keyboard, and the data generated at this time is a standard value in the voltage axis direction (vertical axis in FIGS. 2 and 3) or the time axis direction (FIG. The standard value in the voltage axis direction taking into account the horizontal axis in FIG. 3) is plotted in FIG. 5 when the reference waveform (part of the ideal resin injection pressure waveform) is graphed.

When graphed based on the allowable data for the reference waveform, curves Pb and Pc are obtained. The curve Pb is a waveform when (+1) is the upper limit allowable data with respect to the reference value, and the curve Pc is a waveform when (-1) is the lower limit allowable data.

When the measured waveform has no jitter with respect to the reference waveform, the quality of the waveform can be determined by measuring the deviation from the curve Pa (performed by software). However, as shown in FIG.
When a 'is input, even if it is the same as the reference waveform, it exceeds the allowable range of the upper limit. If this is left as it is, a measurement error will occur.

In the embodiment shown in FIG. 1, the reading of the measured waveform is started from the same trigger level, so that the reading of the measured waveform is started from the same trigger level even if the measured waveform has a jitter Δx. Therefore, this is equivalent to fetching data in a state where the jitter has been corrected, thereby making it possible to avoid measurement errors due to jitter.

In the above-described embodiment, the present invention is applied to the case where the resin injection pressure of the injection molding machine is determined. However, the present invention is applied to the case where it is necessary to measure a plurality of measured waveforms and determine the quality. it can.

[0044]

As described above , according to the waveform judging device according to the present invention, a plurality of measured waveforms are input and the reference waveform or the
/ And measurement when comparing and judging each waveform
Input the waveform and input the rising level and reference level of the waveform.
Trigger output from a comparator that compares
Digital data corresponding to the measured waveform
A plurality of means having a data memory for writing data,
Set the reference level of each comparator to a predetermined value,
And set a predetermined period from each trigger timing,
Digital data corresponding to multiple measurement waveforms for the period
In each data memory .

With this configuration, the input signal level of the waveform is
Trigger timing when bell rises above reference level
Digital data corresponding to the measured waveform as
Since data can be written to the data memory for each means , even when a measurement waveform with jitter is input , the same value
By setting the reference level, each trigger timing
The waveforms can be acquired from the same trigger level . This allows
Waveforms can be accurately compared, and the determination accuracy is improved.

[0046] In addition, even in the measured waveform which is input to the asynchronous, the pre
Set the same period from the trigger timing
In, the attained reduction in the memory capacity it is possible to capture only the waveform area required, as is the memory capacity is aimed high resolution by increasing the amount sampling frequency from the region of the waveform to be captured is reduced It has the feature that the observation accuracy can be improved without increasing. Therefore, the present invention is extremely suitable for application to the above-described waveform determination device such as an injection molding machine.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an example of a waveform determination device according to the present invention.

FIG. 2 is a diagram showing an example of a measured waveform input synchronously.

FIG. 3 is a diagram showing an example of a measurement waveform input asynchronously.

FIG. 4 is a diagram showing an example of a display waveform.

FIG. 5 is a diagram showing a relationship between a reference waveform and an allowable range.

FIG. 6 is a system diagram of a conventional waveform determination device.

FIG. 7 is a diagram showing an example of a measurement waveform input synchronously.

FIG. 8 is a diagram showing an example of a measurement waveform input asynchronously.

FIG. 9 is a diagram showing an example of a display waveform.

[Explanation of symbols]

 Reference Signs List 10 waveform determination device 16, 26 A / D converter 18, 38 data memory 20, 40 comparator 22, 42 memory controller 24 CPU 26 display controller 30 display device (monitor)

Claims (4)

(57) [Claims] 1. A enter the plurality of measurement waveforms, a comparison apparatus for determining each waveform between the rising level of the waveform to input the measured waveform
The input signal level of the waveform is compared with the reference level.
The time when the level becomes higher than the sub-level is output as the trigger timing.
And the trigger timing output from the comparator
Synchronously write digital data corresponding to the measurement waveform
And a plurality of means each having a data memory for setting the reference level of each of the comparators to a predetermined value.
And set a predetermined period from each trigger timing
And a digital signal corresponding to the plurality of measurement waveforms only during the period.
Data data into each of the data memories.
A waveform judging device characterized in that: Wherein said measurement waveform, indicates the pressure of the resin injected into the plurality of cavities formed in the injection mold
2. The waveform judging device according to claim 1, wherein said waveform judging device has a waveform. Wherein when there is jitter on each said measured waveform by injection deviation of the resin injected into the cavity before
To adjust the timing of taking to the serial data memory
Waveform determining apparatus according to claim 2, characterized in that the. 4. A reference level for each of said comparators.
Preset to the same value or / and the trigger timing
The feature is that the same period is set in advance from the
The waveform determination device according to claim 1.