JPH10216919A - Die casting operation monitoring system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To alarm the occurrence of a defective product before occurring the defective product by detecting that defective causes are progressing before actually occurring the defective product in a die casting machine. SOLUTION: In this system, plural factors influenced to the die casting operation that the defective causes are progressing are selected and each factor at the time of operating is measured and calculated to judge the inclination of increasing, holding and decreasing of each factor. Then, the combination of the inclination is compared with a criterion being the combining pattern of the factors of the defective occurring causes, and in the case of matching with the corresponding pattern, the alarm is generated. Further, in this alarming, it can be further indicated where is abnormal in the die casting machine or what comes to the abnormality.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation monitoring system for the operation of die casting of aluminum alloy, zinc alloy or the like.

In die casting, since a molten metal is forcibly filled into a mold at a high speed, defective products due to casting defects are likely to appear.
Therefore, attempts have been made to find out the occurrence of defective products at an early stage (for example, Japanese Patent Application Laid-Open No. H3-189059). However, conventionally, since the determination is made based on one measurement value of a factor affecting the die casting, it is only possible to confirm that a defective product has actually occurred, and the occurrence of the defective product is predicted in advance. I couldn't do that. Also, there are many factors that affect die casting, but the combination of those factors is actually wide-ranging, and even if these factors are determined in combination, the die casting machine is determined by the combination. Because it was not clear where the problem was or what went wrong, it was mostly controlled by one factor. In most cases, the set value is set to a value at which a defective product is manufactured. Therefore, when a warning is issued, the defective product has already been manufactured.

[0003]

SUMMARY OF THE INVENTION The present invention has been devised in order to solve such a problem, and it has been found that the cause of the occurrence of a defect is occurring before a defective product is actually produced. An object of the present invention is to detect a defective product and notify the occurrence of the defective product before it occurs, and issue an alarm.

[0004]

According to the present invention, in order to achieve this object, at least two or more of the factors affecting the die casting are measured and calculated at the time of operation. The tendency of the factor is determined, and the combination of the tendency of each factor is compared with the combination pattern of the tendency of each factor, which indicates that the cause of the defect occurrence is stored in advance, and matches the corresponding pattern. In that case, an alarm was issued. Furthermore, in the alarm,
I was able to show where or what was wrong with the die casting machine. Factors that affect die casting include melt temperature, mold temperature, sleeve temperature, plunger tip temperature, sleeve pressure, coupling pressure (during the injection process and final pressure process), injection cylinder pressure, injection cylinder output, Injection cylinder return pressure, high speed blanking pressure, pouring amount and plunger speed are available.

More specifically, among many factors affecting die casting, in particular, each factor of injection cylinder pressure, sleeve pressure, coupling pressure during the injection process, and plunger speed is measured and calculated for each casting. And subtracting or dividing by the previous casting data or data up to several times before (when using a plurality of data, their arithmetic mean or geometric mean), or the measured data several times A linear regression equation is obtained from the data obtained before, and using the slope thereof, it is determined whether each factor is increasing, decreasing, or holding, and based on a combination of the respective determinations. It is determined whether the operation is in a good state or the cause of failure is occurring in accordance with predetermined criteria (Table 1). When it is determined that the cause of failure is occurring, the operator is notified that the cause of failure is occurring. We also let the operator know where or what went wrong with the die casting machine. Otherwise, the next casting is continued.

Further, by providing a system as shown in the flowchart of FIG. 2, a predicted gate cross-sectional area (A _x ) is calculated, and monitoring based on the calculated gate cross-sectional area (A _x ) enables more accurate detection of gate enlargement and blockage. .

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As a result of intensive research conducted by the present inventors,
From the many factors that affect die casting, select the most important factors to solve the problem, and look at the combination of the increasing, holding, and decreasing trends of these factors to make defective products. It has been found that it is possible to detect that the cause of the defect occurrence is not occurring yet. During die casting, melt temperature or mold temperature, sleeve temperature, plunger tip temperature, sleeve pressure, coupling pressure (at the time of injection process, final pressure process), injection cylinder pressure, injection cylinder output, injection cylinder return pressure, It was found that high speed blanking pressure, pouring amount, plunger speed and the like can be used as indices.

[0008] In order to obtain data for each casting for the melt temperature or mold temperature, sleeve pressure, injection cylinder output, injection cylinder pressure, plunger speed, element factors are measured at the positions shown in FIGS. Then, the measurement results are digitized by appropriate means, digitized, and calculated to obtain data of each factor.
In FIG. 3, reference numeral 1 denotes a pressure head for measuring a hydraulic pressure of a hydraulic circuit. With this pressure head, depending on the casting process,
The pressure in each step of die casting is measured. At the same time, check the time. Numeral 2 denotes a position sensor which measures the displacement of the position of the coupling at each step, and calculates the plunger speed from the displacement at this position and the time at each step measured by the hydraulic head 1. Reference numeral 3 denotes a pressure sensor, which is installed in the coupling portion. Since the pressure sensor is installed in this portion, the force (coupling pressure) truly applied to the molten metal from the plunger excluding the sliding pressure of the injection cylinder, etc. Can be measured and calculated.
The pressure sensor having an overload avoiding mechanism proposed by the inventor of the present invention in Japanese Patent Application No. 8-221726 is preferable because it can accurately measure. Based on the measured force and the plunger speed measured and calculated in 2, the sleeve pressure and injection cylinder output during high-speed injection are calculated by the following equations. Formula for sleeve pressure (P _s ) during high-speed injection process P _s = (P _j2 −P _j1 ) × A _j / A _s where P _s : sleeve pressure (kg / cm ² ) P _j1 : during injection process coupling pressure _{^{(kg / cm 2) P j2}} : Tsui圧coupling pressure during step _{^{(kg / cm 2) a j}} : cross-sectional area of the intermediate cylinder (cm ²⁾ a _s: cross-sectional area of the sleeve (cm ²⁾ · injection cylinder - formula E _c = V _p × output (E _c)
{A _j × (P _j2 −P _j1 ) + P _j1 × A _s } where E _c : injection cylinder output (kgfm / s) V _p : plunger speed (m / s) 4 in FIG. 3 and 5 in FIG. 4 are temperature measuring devices. Measure the temperature of the mold and the molten metal.

The data obtained by each measurement / calculation is subtracted or subtracted from the data at the time of the previous casting or the data up to several times before (when a plurality of data are used, their arithmetic average or geometric average). A linear regression equation is obtained by dividing or measuring the measured data and data up to several times before, and using the slope thereof, whether each factor is increasing, decreasing, or holding tendency. Is determined. When the operation is started or resumed after the interruption, a set value is input as an initial value.

[0010] The retention tendency means a state (range) in which there is no change or very little change in the data. When the increase tendency is larger than the upper limit of the retention tendency, and when the decrease tendency is smaller than the lower limit of the retention tendency, judge. Generally, the range differs depending on the type of the factor.

The combination of the tendency of each factor determined as described above is compared with a predetermined criterion, and it is determined whether or not the cause of the failure is occurring.
If it is determined that the cause of the failure is in accordance with the combination pattern of the probable causes, an alarm is issued to the operator. The alarm may be just an alarm sound,
What is displayed on the display may be used. Of course, you may use together. The content of the cause of the failure that is occurring at that time and the necessary countermeasure can also be notified. Otherwise, the next casting is continued.

When attention is paid to gate blockage (clogging), gate enlargement (erosion), and plunger chip galling, which are problems that often occur in die casting, among the above many factors, the injection cylinder pressure ( It has been found that it can basically be checked by a combination of trends of four factors: P _o ), sleeve pressure (P _s ), coupling pressure (P _j1 ), and plunger speed (V _p ). The four factors are measured and calculated, and the combination of the tendency of each factor determined as described above is compared with the criterion shown in Table 1.
If the cause of the failure matches the combination pattern of the factors that are occurring, an alarm is issued to the operator, and the details of the cause of the failure that is occurring at that time and the countermeasures are also notified. Otherwise, the casting is continued. For example, if the injection cylinder pressure and the sleeve pressure tend to increase and the coupling pressure tends to hold when performing die casting, it is determined that the gate is clogging and an alarm is sounded, and the operation panel The display shows "Gates are likely to be blocked, gates need to be checked". In this case, an alarm is issued regardless of the tendency of the plunger speed to increase, hold, or decrease. However, if the plunger speed is decreasing, it is determined that the closing of the gate is further advanced, and an alarm may be issued in consideration of the fact.

In particular, it has been found that the gate expansion / closure of the system can be more accurately detected using the melt temperature or mold temperature, the sleeve pressure, the coupling pressure during the injection process, and the plunger speed. Measure and calculate the melt temperature or mold temperature, coupling pressure, sleeve pressure and plunger speed for each casting, and determine the melt temperature or mold temperature and coupling pressure among the factors determined as above. A warning is issued if either of the results is not the tendency to hold, and if both the determination results are the tendency to hold, the data of the sleeve pressure and the plunger speed is sent to the arithmetic unit, and it is substituted into the following formula to predict the gate cross-sectional area. (A _x ) is obtained, and the predicted gate cross section is compared with the original gate cross section (A _g ). If the predicted gate cross section (A _x ) is larger than the original gate cross section (A _g ), the gate is determined. A warning was issued to warn of the enlargement, and conversely, if it was small, a warning was issued to close the gate, otherwise the casting was continued. A _x = {ρ × (V _p × A _s ) ² / (C × g × P _s )} ^1/2 where A _x : predicted gate cross section ρ: specific gravity of molten aluminum V _p : plunger speed A _s: Sri - Bed sectional area C: discharge coefficient g: gravitational acceleration P _s: adjusting the degree of difference between the predicted gate cross-sectional area that emits sleeve pressure alarm (a _x) as the original gate cross-sectional area (a _g) By
It is possible to know at an early stage that the gate expansion has started, or to know just before a defective product is manufactured. The operation of each of these steps is performed via a computer having a storage device, an arithmetic device, and an input / output device. For safety, it is desirable to provide a mechanism for detecting whether or not the molten metal leaks from the mold.

[0014]

【Example】

(Example 1) When performing die casting, four factors of injection cylinder pressure (P _o ), sleeve pressure (P _s ), coupling pressure (P _j1 ) and plunger speed (V _p ) were measured and calculated. The obtained data is divided by the arithmetic mean of the previous data to determine the tendency of those factors. The combination pattern of the determination is compared with a predetermined determination criterion, and if the pattern is a combination pattern of factors that match the determination criterion, an alarm sound and an alarm display are performed. The previous data was set as the arithmetic mean of three for each factor.

If the quotient of the division result of each factor is 0.86 to 1.14 in the case of the injection cylinder pressure, it tends to be maintained.
If it was 14 or more, it was determined to be an increasing tendency, and if it was 0.86 or less, it was determined to be a decreasing tendency. 0.852 to 1.148 for sleeve pressure
In the range of 0.9, 0.9 for coupling pressure
If the plunger speed is between 0.93 and 1.07, the tendency is determined to be the holding tendency. If the plunger speed is 0.93 to 1.07, the tendency is determined to be the holding tendency. Was determined. Based on a number of experiments performed in advance, the patterns of the tendency of change of each factor that can be a criterion are arranged as shown in Table 1.

[0016]

The combination of the tendency of each factor obtained above is compared with the criterion shown in Table 1, and if there is a combination pattern of the tendency that matches the criterion, an alarm is issued. . The alarm sounds as well as an indication on the display of the operation panel that informs the contents of the cause of the failure that is occurring at that time and the countermeasure, such as "Gates are likely to be blocked, gates need to be inspected". did. Aluminum alloy was cast by a horizontal cold chamber die-casting machine incorporating a computer set and adjusted to perform the above steps.

When casting was continuously performed, 230
At the time of the second casting, a warning of gate enlargement (E = injection cylinder pressure (P _o ) and plunger speed (V _p ) are increasing, sleeve pressure (P _s ) and coupling pressure (P _j1 ) Tended to be retained). Then, when the die casting machine was stopped and the mold and the product were inspected, traces of erosion were found at the gate of the mold, but the product had a slightly lower specific gravity value (some air bubbles were found due to air entrapment). Was within the regulation, and no abnormality was particularly observed. After repairing the gate portion of the mold, die casting could be performed in the same manner as a normal mold.

(Comparative Example 1) Measurement and calculation are performed in the same apparatus as in Example 1 in the same manner as in Example 1, but a criterion is provided for each factor, and a defective product is generated for each criterion. Aluminum alloy was cast using a horizontal cold chamber die-casting machine equipped with a conventional control / monitoring device that issues a warning when any one exceeds the judgment criteria.

At the time of the 228th casting,
In the system of the present invention, an alarm for gate expansion (K = injection cylinder pressure (P _o ) and coupling pressure (P _j1 ) tends to be maintained, sleeve pressure (P _s ) tends to decrease, and plunger speed (V _p ) tends to increase. ). However, if the casting was continued, the system of the present invention continued to issue an alarm during that time, while the conventional system issued an alert at the 240th time. When the die casting machine was stopped and the mold and the product were examined, the last product had a low specific gravity and was defective. The gate portion of the mold was greatly eroded (enlarged), indicating that significant repair was required. The product from the beginning was also inspected, and the product of the casting up to the 235th time had a specific gravity value within the standard, but the product of the casting after the 236th time had a specific gravity value lower than the standard.

(Embodiment 2) Melt temperature, coupling for each casting
Measures / calculates spring pressure, sleeve pressure and plunger speed
And the data obtained for the melt temperature and coupling pressure
The trend of those factors divided by the arithmetic mean of the three data
Is determined. Either of the judgment results tends to be held
If not, a warning is issued.
Pressure and plunger speed data to the
Predicted gate cross section (A _x )
Measure the gate cross-sectional area to the original gate cross-sectional area (A_g )
And the predicted gate cross section (A_x ) Is the original gate cross section
(A_g If the value is larger than), a gate expansion warning is issued,
If it is too small, it will alert the gate
In such a case, the casting was continued. A_x = ｛Ρ × (V_p × A_s )^Two / (C × g × P_s )｝^1/2  Where A_x : Predicted gate cross section ρ: Aluminum melt
Specific gravity V_p ： Plunger speed A_s : Sleeve cross section C: Outflow coefficient g: Gravity acceleration P_s : Sleeve pressure Here, C = outflow coefficient was set to “200”. Each of them
The step operation includes a storage device, an arithmetic device, and an input / output device.
You made it through a computer.

The temperature of the molten metal is 0.987 to 1.0
13 range from 0.92
1.08 was also regarded as the retention tendency. The predicted gate cross section is divided by the original gate cross section (A _g ). If the quotient is 1.3 or more, a gate expansion warning is issued. If the quotient is 0.7 or less, a gate closing warning is issued. Set to emit.
If it was between the two, the casting was continued.

When casting was continuously performed, 160
At the time of the second casting, a gate closure alarm was issued. Therefore, the die casting machine was stopped and the mold and the product were inspected. Marks of blockage were found at the gate of the mold. The product showed slight wrinkles, but it was light within the regulations and no abnormalities were found.

(Comparative Example 2) Comparative Example 1 was added to the apparatus of Example 2.
A conventional control / monitoring device similar to that described above was additionally provided, and operation was performed under the same conditions as in Example 2. At the time of the 158th casting, a warning of the gate enlargement was issued. However, if the casting is continued as it is, the alarm will continue to be issued.
The conventional system issued a warning. Therefore, the die casting machine was stopped and the mold and the product were inspected. The gate portion of the mold was greatly eroded (enlarged), indicating that significant repair was required. As for the product, the product of the casting up to the 160th time had a specific gravity value within the standard, but the product of the casting from the 161st time onward had a specific gravity lower than the standard.

[0025]

According to the system of the present invention, a defective product has not yet been manufactured, but the cause of the defect is being generated. It is possible to detect the type of cause and prevent the production of defective products. Also, with this method, measures can be taken while the cause of failure is small,
Countermeasures are easy.

[Brief description of the drawings]

FIG. 1 is a flowchart corresponding to the present invention (claim 2);

FIG. 2 is a flowchart corresponding to the present invention (claim 3);

FIG. 3 is a diagram illustrating a position of a sensor for obtaining data according to the present invention;

FIG. 4 is a diagram illustrating a position of a sensor for obtaining data according to the present invention;

[Explanation of symbols]

1: pressure head 2: position sensor 3: pressure sensor 4: thermometer 5: thermometer

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Toshiya Anami 1-34-1, Kambara, Kambara-cho, Anbara-gun, Shizuoka Prefecture Nippon Light Metal Corporation Group Technology Center

Claims (3)

[Claims] 1. Molten metal temperature, mold temperature, sleeve temperature, plunger tip temperature, sleeve pressure, coupling pressure (during injection step, final pressure step), injection cylinder pressure, injection cylinder output, injection cylinder return pressure, It has a mechanism to measure and calculate every two or more factors among the factors affecting die casting, such as high speed blanking pressure, pouring amount and plunger speed, and to make data of each factor, Subtracting or dividing the obtained data of each factor and the data at the time of the previous casting or the data up to several times before (when using a plurality of data, their arithmetic average or geometric average), or A linear regression equation is obtained from the measured data and data obtained several times before, and the slope is used to determine whether each factor is increasing, decreasing, or holding. You Has a mechanism to judge whether the operation is in good condition or the cause of the defect is occurring according to the predetermined criteria based on the combination of the judgments. If it is determined that die is occurring, the operator is notified of the cause of the defect and die casting is stopped if necessary. Casting operation monitoring system. 2. Injection cylinder pressure for each die casting
(P_o ), Sleeve pressure (P_s ), Coupling during the injection process
Pressure (P_j1), Plunger speed (V_p )
Has a mechanism to calculate the data of each factor.
Factor data and the previous casting data or several previous
Data (when using multiple data, their arithmetic
Average or geometric mean).
A linear regression equation is defined based on the specified data and data several times before.
Using the slope, you can see if each factor is increasing
Determine whether it is decreasing or holding.
A criterion consisting of A to N shown below
Has a mechanism to set the tendency of each factor determined.
The cause of the defect is found by comparing the
Has a mechanism to determine whether or not
If it is determined that this is happening,
Notify that a good cause is occurring, and if necessary
A mechanism that interrupts production and otherwise performs the next casting
Die casting operation monitoring system. A: Injection cylinder pressure (P_o ) And sleeve pressure (P_s )When
Coupling pressure (P _j1) Increasing trend, plunger speed
Degree (V_p ) If the tendency to increase, chipping or dieca
Judging that the stomach oil pressure abnormality has begun to occur,
Injection cylinder pressure (P_o ) And sleeve pressure (P_s )
Pulling pressure (P_j1) Increasing trend, plunger speed
(V_p ) Is a tendency to hold or decrease;
Alternatively, it is determined that the blockage of the gate has begun. B: Injection cylinder pressure (P_o ) And sleeve pressure (P_s )But
Increasing trend, coupling pressure (P_j1) Is retention trend, plan
Jar speed (V_p ) Is increasing, holding, or decreasing
If so, it is determined that gate blockage has begun to occur. C: Injection cylinder pressure (P_o ) And sleeve pressure (P_s )But
Increasing trend, coupling pressure (P_j1) And plunger speed
(V_p If) is decreasing, gate blockage is starting to occur
Judge that D: Injection cylinder pressure (P_o ) Increasing trend, sleeve pressure
(P_s ) Is the holding tendency and the coupling pressure (P_j1) Increasing inclination
Direction, plunger speed (V_p ) If the trend is decreasing
It is determined that galling has begun to occur. E: Injection cylinder pressure (P_o ) Increasing trend, sleeve pressure
(P_s ) And coupling pressure (P_j1) Is retention trend, plan
Jar speed (V_p ) Is increasing, gate expansion will occur
Judge that it is starting to grow. F: Injection cylinder pressure (P_o ) Increasing trend, sleeve pressure
(P_s ) Is decreasing and the coupling pressure (P_j1) Increasing inclination
Direction, plunger speed (V_p ) Is a tendency to hold or decrease
If so, it is determined that chip galling has begun to occur. G: Injection cylinder pressure (P_o ) Is holding tendency, sleeve pressure
(P_s ) Is increasing and the coupling pressure (P_j1) Cant hold
Direction, plunger speed (V_p ) Gate if decreasing trend
It is determined that blockage has begun to occur. H: Injection cylinder pressure (P_o ) And sleeve pressure (P_s )When
Coupling pressure (P_j1) Is holding tendency, plunger speed
(V_p ) Is increasing, gate expansion is starting to occur
Judge that J: Injection cylinder pressure (P_o ) Is holding tendency, sleeve pressure
(P_s ) Is decreasing and the coupling pressure (P_j1) Increasing inclination
Direction, plunger speed (V_p ) If the trend is decreasing
It is determined that galling has begun to occur. K: Injection cylinder pressure (P_o ) Is holding tendency, sleeve pressure
(P_s ) Is decreasing and the coupling pressure (P_j1) Cant hold
Direction, plunger speed (V_p ) Gate if increasing trend
It is determined that the expansion has started to occur. L: Injection cylinder pressure (P_o ) Is decreasing, sleeve pressure
(P_s ) Is the holding tendency and the coupling pressure (P_j1) Increasing inclination
Direction, plunger speed (V_p ) If the trend is decreasing
It is determined that galling has begun to occur. M: Injection cylinder pressure (P_o ) Is decreasing, sleeve pressure
(P_s ) And coupling pressure (P_j1) Is retention trend, plan
Jar speed (V_p ) Is increasing, gate expansion will occur
Judge that it is starting to grow. N: Injection cylinder pressure (P_o ) And sleeve pressure (P_s )But
Declining trend, coupling pressure (P_j1) Is increasing, plan
Jar speed (V_p If) is decreasing, chip galling
Is determined to have started to occur. 3. A plunger speed for each die casting.
It has a mechanism to measure and calculate the sleeve pressure, the coupling pressure during the injection process, the molten metal temperature or the mold temperature, and use it as data for each factor. The data obtained by subtracting or dividing by the data at the time of casting or the data up to several times before (or the arithmetic mean or geometric mean when using a plurality of data), or the data measured several times before A primary regression equation is obtained from the data, and a gradient is used to determine whether each factor is increasing, decreasing, or holding. First, the temperature of the molten metal or the mold is determined. The judgment result of the temperature and the coupling pressure is examined, and if either of the judgment results does not tend to hold, a warning is issued. If both the judgment results tend to hold, the sleeve pressure and the plunger are determined. Substituting the speed data into the following equation Gate - DOO sectional area sought (A _x), the prediction gain - originally is set bets sectional area previously gate -
Gate cross section (A _x ) compared with the predicted gate cross section (A _g )
Is larger than the original gate cross-sectional area (A _g ), it issues a warning of gate enlargement, interrupts casting if necessary, and conversely issues a warning of gate blockage if smaller, and casts if necessary. Die casting operation monitoring system with a mechanism to interrupt and otherwise perform the next casting. A _x = {ρ × (V _p × A _s ) ² / (C × g × P _s )} ^1/2 where A _x : predicted gate cross section ρ: specific gravity of molten aluminum V _p : plunger speed A _s : Cross section of sleeve C: Outflow coefficient g: Gravitational acceleration P _s : Sleeve pressure