JP2001150092A - Ajusting method and device for kneading molding sand - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remarkably stabilize molding sand after kneading-adjusting when the molding sand is kneading-adjusted by means of a decompression kneading machine. SOLUTION: The molding sand before kneading and an additive agent are charged into a vacuum kneading machine 1, and water content and temperature of the molding sand before kneading containing the addition agent are measured. A first correction water content is calculated so as to bring the water content after kneading close to a target water content based on the measured water content, a second correction water content is calculated based on the measured temperature, and the water content of a total water quantity to be added based on these first and second correction water contents is charged into the vacuum kneading machine 1. Thus, the vacuum kneading machine 1 is held in a decompression condition and the molding sand, the addition agent and the water content are kneaded under the decompression condition. When the second correction water content is calculated, the calculated correlation of the second correction water content differs according to which temperature field the measured temperature belongs to.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for kneading molding sand using a vacuum kneader.

[0002]

2. Description of the Related Art Conventionally, in a green mold molding line for molding a green mold for casting, a process of kneading and adjusting a molding sand,
There is a step of molding the adjusted molding sand. Usually, after casting is performed using a molded mold, the mold used there is separated and collected. The recovered molding sand (recovered sand) is again supplied to the kneading adjustment step as the next and subsequent molding sand. Thus, the foundry sand is used many times through the series of circulation cycles. Of course, fresh sand may be added as needed.

When the above-mentioned recovered sand is used again in the kneading adjustment step, the recovered sand has a considerably high temperature at the time of recovery. For this reason, in recent years, a technique using a reduced-pressure kneader capable of performing kneading while maintaining the inside of the kneader at a predetermined degree of vacuum has been developed. When such a reduced-pressure kneader is used, high-temperature recovered sand is rapidly dispersed in the kneader.
It can be cooled down to about ° C. Thus, 40
If the temperature of the recovered sand is lowered to about ° C or lower, a desired moisture ratio can be maintained.

[0004] In addition, the use of a vacuum kneader has the following advantages. That is, bentonite as an additive adheres to the periphery of the sand particles, and the bentonite exhibits viscosity only when water is present, and the sand particles can be bonded to each other. In this bentonite, water vapor is more easily absorbed than water as a liquid, and therefore, water vapor is more likely to exhibit adhesive strength than water. In this regard, according to the above-described vacuum kneader, steam easily penetrates into the bentonite, and as a result, the holding strength of the mold can be further increased when the mold is formed even with a relatively small amount of water. Also, even during casting, the water content of the molten metal is easily absorbed by bentonite,
There is also an advantage that gas defects hardly occur.

[0005]

However, the above technique has the following problems. That is, at the end of kneading, the foundry sand needs to have suitable characteristics for molding, and one of the characteristics is moisture (moisture ratio). That is, it is desirable that the moisture after kneading is closer to the target moisture. Conventionally, the water content of the recovered sand is measured before kneading, and the amount of water is calculated in consideration of the difference from the target water content, and water is added by that amount during kneading.

However, in practice, it is necessary to consider the evaporation of water during kneading. For example, if the temperature of the recovered sand before kneading is much higher than 40 ° C., the temperature will drop significantly during kneading, and the amount of evaporation will increase accordingly. On the other hand, even if the temperature of the recovered sand before kneading is lower than 40 ° C., if the amount of evaporation during kneading is ignored, stable kneading sand characteristics cannot be obtained. Therefore, upon kneading, it is necessary to determine the amount of water to be added and give it in, taking into account the above-mentioned amount of evaporation.

[0007] The present invention has been made in view of the above-mentioned problems, and an object thereof is to remarkably stabilize molding sand after kneading adjustment in kneading adjustment using a vacuum kneader. It is an object of the present invention to provide a kneading adjustment method and a kneading adjustment device for molding sand that can be used.

[0008]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a step of charging a molding sand before kneading and an additive into a kneading machine, and a kneading process containing the additive. Measuring the moisture and temperature of the pre-molding sand or the pre-kneading molding sand, and calculating a first correction moisture to bring the moisture after kneading closer to the target moisture based on the measured moisture, and Calculating a second corrected moisture based on the measured temperature in consideration of the above, and introducing a total amount of water based on the first and second corrected moisture into the kneading machine; A method for adjusting the kneading of molding sand, which comprises maintaining the pressure in a reduced pressure state and kneading the molding sand, additives and water in the kneader under the reduced pressure. Here, the moisture and the target moisture may be a moisture percentage, a parameter corresponding thereto (for example, a CB value), or a moisture amount as an absolute amount in consideration of sand weight. (The same applies hereinafter). The CB value is also called a compactability index, and has a close relationship with the water content in sand. More specifically, the CB value refers to a casting sand having a predetermined size (height 100 mm
mm), and it is hardened or pressurized three times, and the sinking depth is divided by the height in the first container, and is the amount of compressive deformation expressed as a percentage.

According to the first aspect of the present invention, the molding sand before kneading and the additives are charged into the kneading machine. Further, the moisture and the temperature of the molding sand before kneading containing the additive or only the molding sand before kneading are measured. Then, based on the measured moisture, the first moisture is adjusted to bring the moisture after kneading closer to the target moisture.
Is calculated, and the second corrected water is calculated based on the measured temperature in consideration of the evaporation, and the water having the total water amount based on the first and second corrected water is calculated. , Into the kneader. Further, the inside of the kneader is maintained at a reduced pressure, and the molding sand, additives and water in the kneader are kneaded under the reduced pressure. Therefore, the molding sand before kneading containing the additive measured before kneading, or the temperature of the molding sand before kneading, the amount of water to be charged is finely adjusted in consideration of the amount of evaporation. . Therefore, the variation in the casting sand characteristics after kneading is reduced.

According to a second aspect of the present invention, in the method for adjusting the kneading of foundry sand according to the first aspect, the temperature range to which the measured temperature belongs when the second corrected moisture is calculated. The gist is that the correlation of the second corrected moisture calculated by the above is made different.

According to the second aspect of the present invention, in addition to the operation of the first aspect, when calculating the second corrected moisture, the temperature range to which the measured temperature belongs depends on the temperature range. The calculated second corrected moisture has a different correlation. For this reason, it is possible to obtain more accurate corrected moisture according to the temperature.

Further, according to a third aspect of the present invention, in the method for adjusting the kneading of the molding sand according to the second aspect, the second aspect of the invention is characterized in that:
The gist of the present invention is that the gradient of the calibration curve considered in the calculation is changed depending on the temperature range to which the measured temperature belongs when calculating the corrected moisture.

According to the third aspect of the invention, in addition to the operation of the second aspect of the invention, a calibration curve is taken into account when calculating the second corrected moisture. The slope of the calibration curve differs depending on the temperature range to which the measured temperature belongs. For this reason, it is possible to obtain more accurate corrected moisture according to the temperature.

According to a fourth aspect of the present invention, in the method for adjusting the kneading of the foundry sand according to the second or third aspect, the measured temperature is adjusted when the inside of the kneading machine is maintained at a reduced pressure. The gist is that the second corrected moisture is taken into consideration even when the temperature is lower than the temperature.

According to the fourth aspect of the present invention, in addition to the effects of the second and third aspects of the present invention, the measured temperature is the temperature when the inside of the kneader is maintained at a reduced pressure. Even so, the second corrected moisture is taken into account. For this reason, it is possible to appropriately deal with subtle moisture evaporation.

In addition, according to a fifth aspect of the present invention, in the method for adjusting the kneading of the foundry sand according to any one of the first to fourth aspects, the target is determined based on the moisture of the foundry sand after the kneading adjustment before the previous minute. The gist of the invention is that at least one of the correction of the moisture and the adjustment of the additive introduction amount based on the coercive pressure of the foundry sand before and after the kneading adjustment is performed. Here, "before the last minute" means that only the last minute may be considered, or several previous data (for example, an average value) may be considered.

According to the fifth aspect of the invention, in addition to the effects of the first to fourth aspects, the target moisture is corrected based on the moisture of the molding sand after the kneading adjustment before the previous minute. In this case, it is possible to reduce the variation in moisture in each kneading adjustment step. Further, when the additive amount is adjusted based on the coercive force of the foundry sand before and after the previous kneading adjustment, it is possible to reduce the variation in coercive force in each kneading adjustment step.

Further, according to the invention described in claim 6,
A kneading machine capable of kneading the inside under reduced pressure, molding sand before kneading into the kneading machine, respective charging means for measuring and introducing each of the additive and water, and molding sand before kneading containing the additive, or Measuring means for measuring the moisture and temperature of the molding sand before kneading, and calculating a first corrected moisture to bring the moisture after kneading closer to the target moisture based on the moisture measured by the measuring means, Calculating means for calculating a second corrected moisture based on the measured temperature in consideration of the consideration, and calculating an amount of water to be charged into the kneader based on the first and second corrected water, The calculating means,
The gist of the present invention is a molding sand kneading adjusting device for calculating the second corrected moisture based on a calibration curve having a different correlation depending on which temperature range the measured temperature belongs to.

According to the sixth aspect of the present invention, the casting sand, the additive and the water before kneading are measured and charged into the kneading machine by the respective charging means. Then, kneading is performed in a kneader under reduced pressure. Here, the moisture and the temperature of the molding sand before kneading containing the additive or only the molding sand before kneading containing the additive are measured by the measuring means. Then, based on the moisture measured by the measuring means, the first corrected moisture is calculated by the calculating means so as to bring the moisture after kneading closer to the target moisture, and the measured temperature is taken into account in consideration of the evaporation. The second corrected moisture is calculated based on
Then, the amount of water to be charged into the kneader is calculated based on the second corrected moisture. Then, the calculating means calculates a second corrected moisture based on a calibration curve having a different correlation depending on which temperature range the measured temperature belongs to. Therefore, the amount of water to be charged is finely adjusted according to the temperature of the pre-kneading molding sand containing the additive or the pre-kneading molding sand containing the additive measured before kneading. Therefore, the variation in the casting sand characteristics after kneading is reduced.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method and an apparatus for kneading and adjusting molding sand will be described below in detail with reference to the drawings.

FIG. 1 schematically shows a kneading adjusting device for kneading and adjusting molding sand. As shown in the figure, the kneading adjusting apparatus according to the present embodiment includes a vacuum kneader 1, and the vacuum kneader 1 is connected to a vacuum pump through a vacuum pipe 2 so as to communicate with the tank. 3 are connected.

Above the vacuum kneader 1, a sand meter 4, an additive meter 5 and a water meter 6 are provided, respectively. Bentonite as an additive is introduced into the additive measuring device 5, and the weight of the bentonite is measured by a load cell (not shown). The sand meter 4 is charged with the recovered foundry sand (and in some cases, fresh sand: hereinafter referred to as “recovered sand” for convenience) and the measured bentonite. The weight of the collected sand and bentonite is measured by a load cell.

Further, the vacuum kneader 1 is provided with a sand temperature / moisture measuring sensor (hereinafter referred to as an FK sensor) 7. The FK sensor 7 is disposed so as to be able to come and go in the tank of the vacuum kneader 1 by a cylinder or the like, and can measure the temperature and moisture of the collected sand and the like in the tank.

Further, in the lower part of the vacuum kneader 1,
A kneading sand hopper 8 and a cutting feeder 9 are provided. After kneading, the kneading sand is discharged from the vacuum kneader 1 to the kneading sand hopper 8 and guided from the hopper 8 to the cut-out feeder 9. A belt conveyor 11 is provided below the cut-out feeder 9.
1, the kneading sand is guided to a molding machine (not shown).

At the same time, in the middle of the belt conveyor 11,
A sand characteristic value measurement sensor 12 is provided. Then, the CB value and the coercive pressure are measured by the sand characteristic value measuring sensor 12, and these sand characteristic values are considered as data of the previous batch at the time of the present kneading. here,
As described above, the CB value is also referred to as a compactibility index, and is an index representing the amount of compressive deformation. There is a close correlation between the CB value and the moisture value (the higher the moisture value, the greater the CB value). In addition, the coercive pressure is an index indicating the strength and hardness of the mold when the kneading sand is formed. There is a close correlation between the coercive pressure and the amount of the additive (bentonite) added (the greater the amount of added bentonite, the greater the coercive pressure).

The kneading adjusting device includes the sensors 7, 12
A control device (not shown) is provided to control actuators such as various feeders and the vacuum pump 3 based on data and various signals input from the controller. Next, various processing contents executed by the control device at the time of kneading adjustment will be described with reference to the flowcharts of FIGS.

In the kneading adjustment step, the controller first performs feedback correction based on the data of the previous batch before the kneading. That is, in step S101, the current target moisture value is set based on the CB value of the previous batch. More specifically, for example, it is assumed that the management range of the CB value is 38% or more and 42% or less. If the CB value in the previous batch is within the above range, in the current process, the previous target moisture value is used without changing the target moisture value. Further, for example, when the CB value in the previous batch exceeds 42%, the target moisture value is set lower by that amount in the current process, and conversely, the CB value in the previous batch becomes 3%.
If it is less than 8%, the target moisture value is set higher by that amount in the current processing.

In the following step S102, the control device sets the current additive amount based on the coercive pressure of the previous batch. More specifically, for example, it is assumed that the management range of the coercive pressure is 0.9 or more and 1.1 or less. When the coercive pressure in the previous batch is within the above range, in the present process, the previous input amount is used without changing the additive input amount. Further, for example, when the coercive pressure in the previous batch exceeds 1.1, the additive input amount is set lower by that amount in this process, and conversely, when the coercive pressure in the previous batch is less than 0.9, In the present process, the additive amount is set higher by that amount.

Next, in step S103, the control device drives and controls the sand feeder, puts the recovered sand into the sand meter 4, and weighs the sand to a predetermined weight.

Subsequently, in step S104, the additive measured by the additive measuring device 5 is supplied to the sand measuring device 4 so as to have the amount set in step S102.

Thereafter, in step S105, the control device determines whether or not there is a kneading start signal. If a negative determination is made, the control unit repeats the process until a positive determination is made. On the other hand, when there is a kneading start signal, in step S106, the vacuum kneader 1
The mixture of the recovered sand and the additive already charged is charged into the sand meter 4.

Subsequently, in step S107, the cylinder is driven and controlled so that the FK sensor 7 is extended into the tank of the vacuum kneader 1, and the recovered sand put into the tank using the FK sensor 7 is controlled. And the temperature (sand temperature t) and moisture of the mixture of additives and additives (mostly recovered sand).

In the following step S108, a first corrected moisture, which is a main corrected moisture, is set based on the moisture detected this time and the target moisture value set in step S101. For example, if the target moisture value is 4% and the moisture detected this time is 1%, the difference is 3%
Is set as the first corrected moisture.

Further, in the next step S109,
A second corrected moisture is set based on the sand temperature t. here,
In calculating the second corrected moisture, a calibration curve shown in FIG. 4 is used. In the present embodiment, the calibration curve includes a first calibration curve L1, a second calibration curve L2, a third calibration curve L3, and a fourth calibration curve L4. Each calibration curve L1
L4 has different intercepts and gradients, and is empirically set based on actual data so that the gradient increases as the temperature increases.

The calibration curve L used (considered)
1 to L4 differ depending on the temperature range to which the sand temperature t belongs. That is, the sand temperature t is t1 (for example, t1 = 27
° C) to t2 (for example, t2 = 33 ° C), the second calibration moisture (a ≤ second compensation moisture ≤ b) is set in consideration of the first calibration curve L1. . Further, when the sand temperature t is in the temperature range from t2 to t3 (for example, t3 = 40 ° C .: the boiling point of water under reduced pressure in the present embodiment), the second calibration curve L2 is taken into consideration and the second calibration curve L2 is taken into consideration. Corrected moisture (b
.Ltoreq.second corrected moisture.ltoreq.c). Furthermore, the sand temperature t
Is in the temperature range from t3 to t4 (for example, t4 = 70 ° C.), the second correction moisture (c ≦ the second correction moisture ≦ d) is set in consideration of the third calibration curve L3. . together,
If the sand temperature t is in the temperature range equal to or higher than t4, the second calibration moisture (d ≦ the second calibration moisture) is set with reference to the fourth calibration curve L4.

In the next step S110, the total water content is set based on the first and second corrected water contents set in steps S108 and S109, and the current sand weight. The total amount of water is measured by the water meter 6 and the water is put into the tank of the vacuum kneader 1.

Next, in step S111, the control device drives and controls the vacuum pump 3 to reduce the pressure inside the vacuum kneader 1. At this time, the pressure in the vacuum kneader 1 is maintained at 74 hPa so that the temperature in the kneader 1 is set to approximately 40 ° C. as described above. Then, in step S112, the vacuum kneader 1 is maintained for a predetermined time while the reduced pressure state is maintained.
Knead the sand inside.

Further, after a predetermined time has elapsed, the depressurized state is released in step S113, and the kneaded sand is discharged to the kneaded sand hopper 8 in step S114. Subsequently, in step S115, the cutting feeder 9 is drive-controlled to cut the kneaded sand in the kneaded sand hopper 8 onto the belt conveyor 11. At the same time, the belt conveyor 11 is operated to convey the cut kneaded sand to the molding machine.

At the same time, with respect to the kneaded sand on the belt conveyor 11, the CB value and the coercive pressure are measured when the sand reaches the sand characteristic value measuring sensor 12 in step S116. Then, the CB value and the coercive pressure measured here are adopted as the data of the previous batch in the next kneading adjustment step.

As described above, according to the present embodiment, the first corrected moisture, which is the main corrected moisture, is calculated based on the moisture of the recovered sand detected this time and the target moisture value.
In addition, based on the sand temperature t, the second corrected moisture in consideration of the evaporation is calculated, and the water content is set based on these. For this reason, the amount of water to be introduced is finely adjusted appropriately in consideration of the evaporation, and as a result, the variation in the molding sand characteristics (particularly, moisture) after kneading is reduced, and the stability is remarkably stabilized. Can be achieved.

Particularly, in this embodiment, four calibration curves L1 to L4 having different correlations depending on the temperature range to which the sand temperature t belongs.
, The second corrected moisture was calculated. Therefore, it is possible to obtain more accurate corrected moisture in accordance with the sand temperature t, and it is possible to more reliably exert the above-described effects.

Furthermore, in the present embodiment, the second corrected moisture is considered even in a temperature range of 40 ° C. or less, so that even when the temperature of the recovered sand is relatively low, an appropriate amount of water is added. As a result, the casting sand characteristics can be remarkably stabilized.

Next, in order to confirm the above-mentioned effects, an experiment was performed in comparison with the conventional example, and the results are shown below. First, kneading adjustment was performed on recovered sand having various recovered sand temperatures (sand temperature t) by employing the above-described adjustment method of the present embodiment. On the other hand, as a conventional example, kneading adjustment was performed on recovered sand having various recovered sand temperatures using a conventional method (a method of determining the amount of water based on the difference between the recovered water and the target water). .

FIG. 5 shows the relationship between the recovered sand temperature (sand temperature t) and the CB value of the sand after kneading. As shown in the figure, it can be seen that the CB value has a very large variation in the conventional example, while there is not much variation in the present embodiment. Particularly, in the present embodiment, the recovered sand temperature is 40 ° C.
It can be seen that the CB value does not vary even in the following temperature range (around 40%), whereas in the conventional example, the CB value greatly varies particularly in such a low temperature range.
As is clear from the above, according to the present embodiment, it can be said that regardless of the temperature of the recovered sand, the molding sand after kneading can always obtain stable moisture characteristics.

FIG. 6 is a graph showing the water difference (difference between the target water value and the actually measured value) with respect to the recovered sand temperature (sand temperature t) and comparing the conventional example with the present embodiment. As shown in the figure, in the present embodiment, the moisture difference is within 0.8% in all temperature ranges, whereas in the conventional example, the moisture difference is 0.8% or more in most cases. It can be seen that variations have occurred. Therefore, according to the present embodiment, it can be said that, regardless of the temperature of the recovered sand, the moisture of the molding sand after the temperature kneading can be made closer to the target moisture.

FIG. 7 is a graph showing the relationship between the CB value derived from FIGS. 5 and 6 and the water difference. As shown in the figure, if there is no variation in the CB value, no variation occurs in the moisture difference.

As described above, according to the method and the apparatus for kneading molding sand of the present embodiment, when the kneading adjustment of the molding sand is performed using the vacuum kneader 1, the stability of the molding sand after the kneading adjustment is remarkably stabilized. It can be said that this can be achieved.

It should be noted that the present invention is not limited to the contents described in the above embodiment, and may be implemented as follows, for example.

(A) In the above embodiment, four calibration curves L1 to L4 were taken into consideration, but five, six,.
For example, more calibration curves may be used. In addition, a separate calibration curve may be considered so as to be able to cope with a low temperature range of t1 or less or a higher temperature range.

(B) The calibration curve may be a straight line as in the above embodiment, or may be a curved line.

(C) In the above embodiment, the first corrected moisture and the second corrected moisture are calculated as percentages, respectively. However, in calculating each of the moisture, the weight of the sand is taken into consideration. The amount of water as an absolute amount may be calculated.

(D) The feedback correction (steps S101 and S102) in the above embodiment may be omitted. Further, one of the feedback corrections may be omitted.

(E) In the above embodiment, the sand temperature t and the water content of the mixture were measured after charging the recovered sand and the additive. However, the sand temperature and the water content of only the recovered sand were measured in advance. You may do it.

(F) In the above embodiment, the sand temperature t and the water content are measured by one FK sensor 7.
The sensor for measuring the sand temperature and the sensor for measuring the moisture may be separately prepared and measured.

Further, creation of a further technical idea which can be understood from the above embodiment will be described.

(1) a step of introducing molding sand before kneading and an additive into a kneading machine; a step of measuring the moisture and temperature of molding sand before kneading containing the additive or the molding sand before kneading; Based on the measured moisture, a first corrected moisture is calculated to bring the kneaded moisture closer to the target moisture, and a second corrected moisture is calculated based on the measured temperature, and the first and second corrected moisture are calculated. A step of introducing the total amount of water based on the water into the kneader, and maintaining the inside of the kneader under reduced pressure, and kneading the molding sand, additives and water in the kneader under the reduced pressure. In the method for adjusting the kneading of foundry sand provided with the above, when calculating the second corrected moisture, a characteristic is given to the correlation of the second corrected moisture calculated for each temperature range to which the measured temperature belongs. Kneading tone of foundry sand Method.

(2) In any one of the above items (1) and (2), the additive is bentonite.

(3) Claims 1 to 6;
In any of (2), when calculating the second corrected moisture, the correlation characteristic of the calculated second corrected moisture is made different from the temperature when the inside of the kneader is maintained in a reduced pressure state. It is characterized by having.

[0059]

As described above in detail, according to the method and the apparatus for kneading molding sand of the present invention, when the kneading adjustment of the molding sand is carried out using a vacuum kneader, the molding sand after the kneading adjustment is remarkable. An excellent effect of stabilization can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a molding sand kneading adjusting device according to an embodiment.

FIG. 2 is a flowchart illustrating a kneading adjustment process performed by a control device.

FIG. 3 is a flowchart showing a continuation of FIG. 2;

FIG. 4 shows the relationship between the second corrected moisture and the sand temperature (calibration curve).
FIG.

FIG. 5 is a graph showing an effect of the present embodiment, and is a graph showing a relationship between a recovered sand temperature and a CB value of kneaded sand.

FIG. 6 is a graph showing a relationship between a recovered sand temperature and a water difference.

FIG. 7 is a graph showing a relationship between a CB value and a water difference.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Vacuum kneader, 3 ... Vacuum pump, 4 ... Sand meter, 5 ... Additive meter, 6 ... Water meter, 7 ... FK sensor, 8 ... Kneading sand hopper, 12 ... Sand characteristic measuring sensor.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toru Umezawa 1 Takano Shinmachi Tenno, Toyota City, Aichi Prefecture Aisin Takaoka Co., Ltd. (72) Inventor Shinichi Nagamatsuken 1 Takaoka Shinmachi Tenno, Toyota City, Aichi Prefecture Aisin Takaoka Stock In-company (72) Inventor Shigeru Kobayashi 1210 Nokodaidai, Yoshioka-shi, Osaka-cho, Katori-gun, Chiba Japan Erich Co., Ltd. (72) Inventor Yoshihiko Kondo 1210 Kimura-daiki, Yoshioka, Daiei-cho, Katori-gun, Chiba Japan Erich Co., Ltd. F term in the company (reference) 4E093 BA05 BA10

Claims (6)

[Claims] 1. A step of charging a molding sand before kneading and an additive into a kneading machine; a step of measuring the molding sand before kneading containing the additive or the moisture and temperature of the molding sand before kneading; Based on the determined moisture, a first corrected moisture is calculated to bring the water after kneading closer to the target moisture, and a second corrected moisture is calculated based on the measured temperature in consideration of the evaporation. A step of introducing the total amount of water based on the first and second corrected moisture into the kneading machine, and maintaining the kneading machine in a reduced pressure state, and molding sand, additives and the like in the kneading machine under the reduced pressure state. A method for kneading molding sand, comprising a step of kneading water. 2. The method for adjusting the kneading of molding sand according to claim 1, wherein the second corrected moisture is calculated based on which temperature range the measured temperature belongs to when calculating the second corrected moisture. A method for adjusting the kneading of foundry sand, characterized in that the correlations between them are different. 3. The method for adjusting the kneading of foundry sand according to claim 2, wherein, when calculating the second corrected moisture, the slope of the calibration curve considered in the calculation differs depending on the temperature range to which the measured temperature belongs. And a method for adjusting the kneading of the foundry sand. 4. The method for kneading molding sand according to claim 2, wherein the measured temperature is lower than a temperature when the kneader is maintained in a reduced pressure state. A method for adjusting the kneading of molding sand, wherein the second corrected moisture is taken into consideration. 5. The method according to claim 1, wherein the target moisture is corrected based on the moisture of the molding sand after the kneading adjustment before the last minute. A method for adjusting the kneading of the molding sand, wherein at least one of adjusting the amount of the additive based on the coercive force of the molding sand after the kneading adjustment is performed. 6. A kneading machine capable of kneading the inside under reduced pressure, respective charging means for measuring and charging each of the molding sand, additive and water before kneading into the kneading machine, and kneading containing the additive Measuring means for measuring the moisture and temperature of the pre-molding sand or the molding sand before kneading, and calculating the first corrected moisture to bring the moisture after kneading closer to the target moisture based on the moisture measured by the measuring means. And calculating a second corrected moisture based on the measured temperature in consideration of the evaporation, and calculating an amount of water to be charged into the kneader based on the first and second corrected moisture. Means, wherein the calculation means calculates the second corrected moisture based on a calibration curve having a different correlation depending on which temperature range the measured temperature belongs to. Kneading adjustment device.