JPH0112650B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is suitable for use in molding machines that inject molten material into molds, such as transfer molding machines and injection molding machines, and improves the quality of molded products. In particular, the present invention relates to a method of monitoring the molding state by detecting physical quantities that influence the temperature, pressure, speed, time, position or movement of an injection plunger or screw.

In recent years, the required quality of some molded products has become increasingly strict, and in order to streamline production, automatic discrimination and sorting of good and defective molded products, as well as early detection of machine failures or malfunctions, are becoming more and more stringent. Due to this demand, various monitoring methods have been invented and implemented.

There are many factors that influence molded product quality, such as molten material temperature, injection pressure, injection speed, mold temperature, molten material pressure in the mold, and quality of molding material. It is extremely important for these molding conditions to be stable in order to produce good products, and conversely, all products produced under the same molding conditions can be said to have the same quality, so monitoring the molding machine is important to ensure the quality of the molded products. It is an important item that is indispensable for management.

In conventional monitoring methods, predetermined physical quantities that directly or indirectly affect molded product quality, such as speed, pressure, time, injection plunger position or stroke, and temperature, are measured for each molding cycle. It was determined whether the value was within the preset upper and lower limits of tolerance, and if it deviated from the tolerance range, an abnormality signal was generated, and molded products produced under abnormal conditions were determined to be defective.

In addition, as an improvement on this, a reference value is set in advance as a monitoring value, the extent to which the actual measured value fluctuates relative to the reference value is monitored, and if it deviates from the allowable fluctuation range, an abnormality signal is issued and A method has also been implemented in which the difference between the reference value and the actual measurement value is recorded using a printer.

The conventional monitoring method described above only sets and monitors one allowable range of variation, so even if the actual measured value deviates from the allowable range of variation during unmanned automatic driving, it is not possible to determine the extent of the deviation. However, this method has the disadvantage that the detection of serious abnormalities is delayed.

On the other hand, the reasons why the physical quantities to be monitored vary from shot to shot include machine-specific factors, machine malfunctions, mold temperature control characteristics, changes in the oil temperature of the machine drive hydraulic power source, etc. There are various factors such as variations in the quality of materials, and these factors can vary singly or in combination in pressure, temperature, etc. and affect the quality of molded products, and it is extremely important for management to know the degree of variation in the physical quantities mentioned above. Become. In addition, quality control of molded products does not only involve simply determining whether the molded product is good or bad, but also monitors not only the machine itself, but also all conditions that directly or indirectly affect the quality of the molded product, and monitors the operating status. The ideal is to manage the

Considering the cost balance including economy and operability, few of the physical quantities mentioned above,
It goes without saying that it is better to effectively use and monitor those factors that have the greatest effect, but also to select a limited number of monitoring factors that have the greatest effect, and use those physical quantities more effectively for monitoring. This is desirable.

Furthermore, among the fluctuation values of each molding cycle such as pressure, speed, temperature, etc., the range of fluctuations caused by machine-specific characteristics is generally smaller than the allowable range of fluctuation required for molded product quality, and When a machine breaks down or malfunctions, the range of variation is larger than the range of variation caused by the unique characteristics of the machine, and often the range of variation is even larger than the allowable range of variation required for molded product quality. Additionally, if the measured value falls within the range of fluctuation caused by machine-specific characteristics (excluding machine operation fluctuations due to changes in oil temperature, etc.), the molded product produced at that time is generally considered to be a good product. I can say that.

In addition, molding machines require so-called thermal management such as material melting temperature control, hydraulic oil temperature control, mold temperature control, etc. Especially when running for a long time, various conditions become delicately complex and must be monitored. Physical quantities fluctuate cyclically between each molding cycle, even though this is not due to machine failure.

For these reasons, if the degree of variation in monitored physical quantities between each molding cycle could be detected inexpensively and with ease, it would not only be convenient for quality control of molded products, but also prevent machine failure or It is also easier to detect malfunctions.

The present invention has been made in view of the above circumstances, and its purpose is to improve the injection pressure, injection speed, metering time, primary injection pressure time, position and movement amount of the injection plunger or screw, and the metallurgy that affect the quality of the molded product. By measuring physical quantities such as mold temperature and molten material temperature for each molding cycle and classifying and detecting the degree of variation in the measured values according to the degree,
Our goal is to provide a new monitoring method for molding machines that is easy to operate, performs quality control that meets the quality required for molded products, and facilitates the early detection of machine failures and malfunctions. , physical quantities such as pressure, speed, temperature, and time that affect the quality of the molded product of the molding machine are measured for each molding cycle.
In order to monitor the molding state of each molding cycle, a reference value that is obtained when the molded product is a good product is automatically set by sampling and measuring the physical quantities, and is preset in multiple variation width setting devices. A plurality of reference values are obtained by adding and subtracting each set value and the reference value, and a plurality of classifications are performed using the plurality of reference values and the reference value obtained by the sampling measurement as division points. The actual value of the physical quantity measured for each molding cycle is compared with each of the reference values to determine the divisional region to which the actual measurement value belongs, and a signal is generated for each corresponding divisional region to determine the molding state. The physical quantities such as pressure, speed, temperature, and time that affect the quality of molded products of the molding machine are measured for each molding cycle.
In order to monitor the molding state of each molding cycle, a reference value that is obtained when the molded product is a good product is automatically set by sampling and measuring the physical quantities, and is preset in multiple variation width setting devices. A plurality of reference values are obtained by adding and subtracting each set value and the reference value, and a plurality of classifications are performed using the plurality of reference values and the reference value obtained by the sampling measurement as division points. A region is established, and the actual value of the physical quantity measured for each molding cycle is compared with each of the reference values to determine the divisional region to which the actual measurement value belongs, and a predetermined display symbol corresponding to each divisional region is determined. The actual measurement value is recorded and monitored according to a signal output for each segmented area depending on at least one display form among display position, display color, and display color.

Hereinafter, preferred embodiments of the present invention will be described in detail based on the accompanying drawings.

FIG. 1 shows a block diagram of a monitoring device implementing the monitoring method according to the present invention.

1 is a monitoring device, and 2 is a control unit that controls the molding machine.

3 is a measuring section, which measures the injection pressure of the molding machine, molten material pressure, mold temperature, molten material temperature, speed, position and movement amount of the injection plunger or screw, primary injection pressure time, and measurement, which affect the quality of the molded product. A physical quantity such as time is measured for each molding cycle according to a timing command from the control unit 2 using a sensor for detecting the physical quantity or a time counter, and actual measurement value data is detected.

4 is an arithmetic processing unit of the monitoring device having a microprocessor, and is in charge of controlling the monitoring device 1.

Memories 5, 6, 7, 8, 9, 10, and 11 store measured value data or calculated data according to instructions from the calculation processing section 4.

Reference numeral 12 denotes a monitoring mode switch, and the operation of this switch starts and stops the monitoring device.

Reference numerals 13 and 14 are allowable fluctuation width setting devices, each of which has a set value corresponding to a predetermined fluctuation range value, and is calculated by processing this set value and the measured value obtained by sampling measurement. The arithmetic processing unit 4 performs arithmetic processing on the reference value to set a classification reference value for determining whether the molded product is good or bad or whether there is a severe abnormality in the machine.

Note that the reference values obtained by sampling measurements are stored in the memories 6 and 7, and the classification reference values are stored in the memories 8, 9, 10, and 11.

Reference numeral 15 denotes an information output section, which processes and outputs the monitoring information signal from the arithmetic processing section 4, outputs an abnormal signal to the control section 2, and ranks the printer 16 or molded products into good products, defective products, etc. An electrical signal is output to the molded product separator 17, which is a shutter.

18 is an output operation switch, and the arithmetic processing section 4
Switch the monitoring information signal from the controller 2, printer 16, and molded product separator 17 to output ON/OFF.
etc.

The data stored in the memory 11 from the memory 5 can be displayed on the display 20 by operating the data call switch 19, and if necessary, by operating the data call switch 19 and the output operation switch 18. Arithmetic processing unit 4, information output unit 15,
can also be activated and output to the printer 16 for printing out.

A method of monitoring using a monitoring device configured as described above is shown in Figs. 2 and 3 will be explained.

The primary injection pressure time of the above injection molding machine is the primary injection pressure time required in the so-called injection speed control region from the start of injection to the switching to the injection pressure control stroke in the injection process, and the primary injection pressure time is monitored. This means that the stability of the injection speed, the condition of the resin, the condition of the mold, etc. are indirectly monitored, which is very effective in detecting defects such as sink marks and shot shots in molded products. has been made into

Note that FIG. 2 is a relationship diagram between actual measured values and set values, and illustrates the process from the start of molding by automatic operation to the occurrence of an abnormality.

Further, FIG. 3 is a record diagram of actual measurement value fluctuation state showing an example of the molding state printed on recording paper by the printer 17 based on the signal from the monitoring device 1.

First, the sampling section shown in section A-B in FIG. 2 will be explained.

The control section of the injection molding machine will be temporarily set and adjusted, and molding operation will begin automatically. By repeating settings and adjustments through trial and error under this automatic operation, molding conditions that enable molding of a desired molded product are determined. After that, allowable variation range setting device 1
3 and 14 are reset or confirmed, and the monitoring mode switch 12 is pressed to start the operation of the monitoring device 1.

During the first molding cycle, the measuring section 3 measures the injection primary pressure time by counting the clock pulses from the time clock generator in the measuring section 3 according to the signal from the control section 2. The actual measurement value data x is output, and the arithmetic processing unit 4 stores the data x in the memory 5.

When the second molding cycle is performed, the data of the primary injection pressure time is measured in the same manner as above, and this data and the data x in the memory 5 are processed in the arithmetic processing section 4.
A comparison operation is performed at , and the larger data of both data is stored in the memory 6, and the smaller data is stored in the memory 7.

When the third molding cycle is performed, the primary injection time data obtained in the same manner as above is updated and stored in the memory 5, and further this data, the data in the memory 6, and the data in the memory 7 are subjected to arithmetic processing. A comparison operation is performed in the unit 4, and the larger data among the three data is updated and stored in the memory 6 and the smaller data is respectively updated and stored in the memory 7.

From the 4th molding cycle to the 10th molding cycle, the same process as the 3rd molding cycle is performed, and the maximum data of the actual measurement data during the 10 molding cycles is stored in the memory 6 as data x1, and the minimum The value data is stored and fixed in the memory 7 as data x1'.

Therefore, if the first upper and lower limit reference values x1, x1' of the primary injection pressure time and the actually measured data are all the same for 10 times, the standard value x1 is set in memory 6 and memory 7, respectively. The sampling operation process ends.

Note that the number of sampling times is not limited to 10 times, and may be an appropriate number of times greater than or equal to 1 time. In the case of one time, the data may be treated as the standard value x1. Also,
If a molded defective product occurs during sampling, it is due to a setting failure, mechanical abnormality, etc., so investigate the cause and take countermeasures, as well as turn on the monitoring mode switch 1.
2 to turn off the monitoring mode, and then restart the sampling operation process from the beginning.

Furthermore, during operation, if the actual measured value data is within the first upper and lower reference limits, it can be said that the molded product is good, but even if it is outside of this reference value, the molded product is not necessarily determined to be defective. Therefore, the permissible fluctuation range, which will be described later, is set outside the upper and lower reference limits.

When the above-mentioned sampling operation process is completed, the first upper and lower limit reference values x1, x1' stored in the memory 6 and the memory 7 and the set values △x2, △x3 (in addition, △x2 ＜△x3)
The arithmetic processing unit 4 calculates x1+△x2=x2, x1′−△x2=
Addition and subtraction operations are performed on x2′, x1+△x3=x3, x1′−△x3=x3′, and the second upper and lower limit reference values
Obtain upper and lower reference limits x3 and x3'. Then, data x2 is stored in memory 8, and data x2' is stored in memory 9.
Then, data x3 and data x3' are stored in memory 10 and memory 11, respectively, and preparation for monitoring is completed.

Next, the final check section shown in section B-C in FIG. 2 will be explained.

This final check is to check the molding state by automatic operation, and during the final check operation, no matter what range the actual measurement data is with respect to the upper and lower reference limits, the information is sent from the information output section 15 to the molded product separator 17. The command signals shall be the same, and the molded products shall be sorted into positions where the operator can easily check the molded products.

Therefore, the injection primary pressure time data x measured by the measurement unit 3 during the operation is updated and stored in the memory 5, and the data x1, x1',
x2, x2', x3, x3' are compared and processed by the arithmetic processing unit 4, and the data x is x<x3',
x3′≦x<x2′, x2′≦x<x1′, x1′≦x≦x1, x1
It is determined which expression among <x≦x2, x2<x≦x3, and x3<x applies. The results are then output to the information output unit 15 as respective segment signals.

When the data x satisfies x1'≦x≦x1, the operation is normal and the molded product should be of good quality, but for confirmation, it is checked whether the molded product of this molding process is of good quality. Then, the data x is the first upper and lower limit reference value x1, x where x2'≦x<x1' or x1<x≦x2
1' and the second upper and lower reference limits x2 and x2', the molded product was checked at least 10 times during the molding process, and the degree of variation in the measured values was checked at least 10 times. Spread between cycles.

Once this molding condition has been confirmed, the data x
The setting value △
2. Change or confirm Δx3, and complete the final check operation of automatic operation molding before starting completely unmanned operation molding.

Next, the completely unmanned operation section shown in section CD in FIG. 2 will be explained.

In addition, during this operation, the allowable fluctuation range setting device 1
The set value Δx2 of 3 is changed from the value at the final check operation, and the reference values x2 and x2' are also changed accordingly. In addition, by switching the output operation switch 18, the information output section 15 outputs a signal for sorting good products and defective products to the molded product separator 17 based on the signal from the arithmetic processing section 4.
Molded products can be divided into good products and defective products.

Therefore, the actual value data x of the primary injection pressure time measured for each molding cycle is the reference value x
1, x1', x2, x2', x3, x3', and the signal of the segmented area to which the actual measurement data x belongs is output from the arithmetic processing unit 4, and the information output unit 15 compares the data x with x2'. When ≦x≦x2, a good product signal is output, and when x2<x or x2'>x, a defective product signal is output to the molded product separator 17, and the molded products are sorted. Also, if the data x is x>x3 or x
When <x3', the molded product is determined to be defective and is also considered to be seriously abnormal, and the information output unit 15 outputs a signal indicating the abnormality to the control unit 2 of the molding machine, which stops the operation of the molding machine. make it stop.

That is, when the measured value data x indicated by marks △ and ▲ in FIG. It is output from the output section 15. Further, when the actual measurement value data x indicated by an * mark is x>x3, the molding condition is determined to be seriously abnormal, and the operation of the molding machine is stopped.

On the other hand, in order to control the molding state and the quality of molded products, it is necessary to understand the molding state of each molding cycle, and it is desirable to be able to visually check it by recording or displaying it.

In order to meet this demand, as shown in Figure 3, the display symbols are changed and recorded on the recording paper 30 according to the divided areas of the actual measured values, and the positions of the symbols are divided so that the size relationship can be intuitively understood. It is now recorded at a position that corresponds to the area.

That is, a signal from the arithmetic processing unit 4 indicating to which divisional region among the divisional regions set by the allowable variation width value setters 13 and 14 the actual measurement value data x monitored for each molding cycle belongs. , the information output section 15 is activated, and the output signal causes the printer 16 to output the actual measurement value data x to x1'≦
If x≦x1, mark ◎; if x1<x≦x2, mark 〇;
When x2′≦x<x1′, mark ●; when x2<x≦x3, mark △; when x3′≦x<x2′, mark ▲; when x3<x, mark ※; x<x3′ When this is the case, record it with a symbol called an "x" that indicates each segmented area.

It should be noted that since identification is possible by symbols, they may be recorded in one row, or identification may be made by using the same symbol but changing the recording position of the symbol. Furthermore, the display may be displayed in different colors, so that the quality of the molded product, the abnormality of the machine, etc. can be determined at a glance.

In this manner, according to the present invention, the factors of molding conditions that affect molded product quality are measured as physical quantities for each molding cycle, and after automatically setting a plurality of reference values, the degree of variation in the physical quantities is determined. Since it is possible to classify and detect multiple types of information, it is possible to provide a monitoring device that is inexpensive and has excellent operability.

2. It is possible to not only distinguish between good and defective molded products, but also the stability of molding conditions, machine malfunctions, and failures.

3. If the required quality of the molded product is high, the set value Δx2 of the allowable variation width setter 13 may be set to zero and monitored, which further improves operability.

4 It takes time to determine the tolerance range for determining a molded product as good, and if the tolerance range value is set too small, even a good product may be judged as defective, and if the tolerance range value is set too high, it may result in a defective product. Defective products will be mixed in with good products. In order to prevent this from happening, molded products that are determined to be non-defective are subject to tolerances in which the measured value data x is within the first upper and lower reference limits, that is, x1'≦x≦x1, which is outside the first upper and lower limit reference values. Within the fluctuation range value △x2, that is
The molded product is sorted by the molded product separator 17 into x2′≦x<x1′ or x1<x≦x2, and one of the molded products is sorted into x1<x≦x2 or x2′≦x<x1′. If the set value of the allowable range of variation Δx2 is determined by monitoring , the allowable range of variation can be more reliably determined with good operability.

5. If the detection factors are not optimal for determining the quality of the molded product and it is difficult to set the classification of good and defective products, manage the molded products by classifying them according to the classification area of the monitoring device. This eliminates the need for 100% inspection of molded products.

6. Since this is a detection method using segmented areas that can display the degree of variation in data symbolically, graphically, or by color, an inexpensive recording device can be provided, and the recording can be done intuitively and easily to understand the molding state. Since it can be identified, it is extremely effective in terms of quality control.

It has a remarkable effect.

Although the present invention has been variously explained above with reference to preferred embodiments, the present invention is not limited to these embodiments, and it goes without saying that many modifications can be made without departing from the spirit of the invention. It is.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the monitoring device, and FIG. 2 is an explanatory diagram showing the relationship between actual measured values and set values.
FIG. 3 is a diagram showing actual measurement values recorded on recording paper by a printer. DESCRIPTION OF SYMBOLS 1... Monitoring device, 2... Control part, 3... Measuring part, 4...
Arithmetic processing unit, 5, 6, 7, 8, 9, 10, 11...
Memory, 12... Monitoring mode switch, 13, 14
...Allowable variation range setting device, 15...Information output section, 16...
Printer, 17... Molded product separator, 18... Output operation switch, 19... Data call switch, 20... Display, 30... Recording paper, x1, x1'... First upper and lower limit reference values, x2, x2'... Upper and lower reference limits of 2,
x3, x3'...Third upper and lower limit reference values, △x2, △
x3... Allowable width setting value.

Claims (1)

[Scope of Claims] 1 Physical quantities such as pressure, speed, temperature, time, etc. that affect the quality of molded products of a molding machine are measured for each molding cycle, and the physical quantities are measured in order to monitor the molding state of each molding cycle. A standard value that is obtained when the molded product is a good product is automatically set by sampling and measuring, and each preset value set in a plurality of variation range setting devices is adjusted to the standard value. A plurality of reference values are obtained through arithmetic processing, a plurality of segmented areas are created in which the plurality of reference values and the reference value obtained by the sampling measurement are used as division points, and the Monitoring of a molding machine, characterized in that the actual measured value of the physical quantity is compared with each of the reference values to determine the division area to which the actual measurement value belongs, and the molding state is monitored by generating a signal for each applicable division area. Method. 2 Physical quantities such as pressure, speed, temperature, and time that affect the quality of molded products of the molding machine are measured for each molding cycle, and the physical quantities are sampled and measured in order to monitor the molding state of each molding cycle. Therefore, a reference value obtained when the molded product is a good product is automatically set, and each set value predetermined in a plurality of variation range setters and the reference value are subjected to addition/subtraction calculations to obtain a plurality of values. A reference value is determined, a plurality of segmented areas are created using the plurality of reference values and the reference value obtained by the sampling measurement as segmentation points, and the actual value of the physical quantity measured for each molding cycle and the Compare with each standard value to determine the segmented area to which the actual measured value belongs, and select the display format for each segmented area according to at least one of the display symbols, display positions, and display colors predetermined corresponding to each segmented area. 1. A method for monitoring a molding machine, characterized by recording and monitoring actual measured values according to signals output from a molding machine.