JPH0839194A - Molding machine for gas hardening mold - Google Patents

Abstract

PURPOSE:To detect the defective hardening and the deficient strength of a mold at early stage. CONSTITUTION:Gas pressure in a gas blowing chamber 10 at the time of blowing the hardening gas is detected with a gas pressure sensor 17 and monitored by a gas pressure monitoring circuit 18. In the gas pressure monitoring circuit 18, the actually measured gas pressure P1 is compared with the setting gas pressure, and when the actually measured gas pressure P1 exceeds the tolerance limit of the setting gas pressure the output of an interlock signal Q to a molding machine control circuit 16 is stopped. The molding machine control circuit 16 outputs an operation stopping signal and the operation of the molding machine main body 20 on and after the following cycle is stopped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas-curing mold in which a mold-shaped space in a mold is filled with kneading sand, and a hardening gas is passed through the kneading sand to cure the kneading sand. Regarding improvement of molding machine.

[0002]

2. Description of the Related Art FIGS. 3, 4 and 5 show a molding process of a mold by a conventional gas curing mold molding machine.

As shown in FIG. 3, first, the upper die 2 and the lower die 3 of the die 1 are clamped, and then a blow head 4 for blowing sand is brought into pressure contact with the upper surface of the upper die 2 by an air blow method. The kneading sand S in the blow head 4 is blown into the mold 1 through the blow nozzle 5 and the blowing port 6 to be filled.

The kneading sand S is obtained by previously kneading silica sand and a binder at a predetermined ratio. Also, kneading sand S
The air introduced into the mold 1 simultaneously with the blowing of the
It is discharged to the outside of the mold 1 through the vent hole 7 formed in advance.

When a predetermined amount of the kneading sand S has been filled in the mold 1, a molding plate 8 is placed on the upper surface of the upper mold 2 in place of the blow head 4, as shown in FIG. The kneading sand S remaining in the blowing port 6 is pushed into the inside of the mold 1 by the molding pin 9 protruding from the molding plate 8 so that the mold shape is made flush.

Further, the gas injection chamber 10 is pressed against the molding plate 8 and the lower mold 3
The exhaust chamber 11 is also brought into pressure contact with the lower surface side of the molding gas, and the hardening gas generated by the hardening gas generator 12 is passed through the gap between the blowing port 6 on the upper mold 2 side and the molding pin 9 to fill the kneading sand S in the mold 1. Vent inside. The hardening gas introduced into the mold 1 passes through the gap of the filling and kneading sand S and then the exhaust chamber 11
Is discharged to the atmosphere by the blower 13 via the. In addition, 1
Reference numerals 4 and 15 are valves.

The filling and kneading sand S that has come into contact with the hardening gas reacts with the binder in the kneading sand and the hardening gas to harden in a short time, and a mold M having a predetermined shape is formed. After this, as shown in FIG. 5, the mold 1 is opened to open the mold M.
Then, one cycle of the mold making process is completed.

Here, a sealing member (not shown) is provided at the peripheral edges of the openings of the gas blowing chamber 10 and the exhaust chamber 11 to be pressed against the mold 1 so that a predetermined sealing performance is exhibited. It is installed.

[0009]

In the conventional gas curing mold making machine as described above, the curing gas is blown at a preset gas pressure to cure the mold M. Poor curing often occurs. The curing failure here means that the reaction between the binder and the curing gas in the kneading sand is not sufficiently performed for some reason, and even if the curing is performed, the mold strength (hardness) is low, or the mold A state in which a part or the whole surface is not cured and collapses to maintain the shape of the mold.

Such a curing failure is a state in which the diameter of the blow-in port 6 and the diameter of the exhaust vent hole 7 are set to appropriate sizes, and the ventilation pressure and the ventilation time of the curing gas are controlled. Below, mold 1 and each chamber 1
0, 11, a sealing failure, a decrease in the concentration of the hardening gas, an increase in the ventilation resistance due to the clogging of the kneading sand S at the blowing port 6 and the vent hole 7, a fine kneading sand S and a kneading sand S due to overfilling It is caused by the increase of internal ventilation resistance.

Although the above-mentioned defective curing of the mold M can be found by a visual inspection in the subsequent mold assembly process in a general casting factory, it is consistent from the molding process to the casting process as recently. In an automated casting line,
It is not preferable because it cannot be found up to the final finish inspection step of the cast product, and a large number of product (cast) defects are caused due to the curing failure of the mold itself.

Further, in order to accurately and promptly detect the curing failure of the mold in the automated casting line, there is no method other than relying on the visual inspection of the process by patrol and the visual inspection of the mold in the next process. As described above, all the molds that are formed by the time the defective curing is found will be defective products.

In addition, since the lack of mold strength caused by insufficient ventilation of the hardening gas cannot be found by visual inspection of the mold M, there is no method other than performing a sampling strength sampling test. In that case, the insufficient strength of the mold is discovered only when the dimension defect of the product cast by using the mold occurs, and in this case also, many defective products of the mold occur, which is not preferable.

The present invention has been made by paying attention to the above problems. If the gas pressure in the gas blowing chamber at the time of venting the curing gas is within a specific range with respect to the original pressure on the gas generator side. By monitoring the gas pressure in the gas blowing chamber, paying attention to the fact that there is no curing failure of the mold and that the required strength of the mold can be satisfied, especially the cost of the defective mold material is reduced, and the product defect due to the mold defect is caused. It is an object of the present invention to provide a gas-curing mold making machine capable of eliminating the occurrence and improving the productivity of the molding line.

[0015]

According to a first aspect of the present invention, a mold is formed by filling a kneaded sand obtained by previously kneading silica sand and a binder with each other in a mold clamped from a blowing port of the mold. , After filling with kneading sand, cover the blow-in side of the mold with a gas blowing chamber, and let the hardening gas flow from the hardening gas generator through the gas blowing chamber and the blowing hole into the mold to cure the mold. In the gas curing mold making machine, the gas pressure sensor for detecting the gas pressure in the gas blowing chamber is compared with the actually measured gas pressure of the curing gas detected by the gas pressure sensor and the preset gas pressure. And a control unit that outputs a gas pressure abnormality signal when the measured gas pressure exceeds the allowable limit of the set gas pressure.

According to a second aspect of the invention, in addition to the requirements of the first aspect, the set gas pressure is set within a pressure range of 50 to 90% of the original pressure on the side of the curing gas generator. It is characterized by that.

According to a third aspect of the present invention, in addition to the requirements of the first or second aspect, the abnormal gas pressure signal output from the control means causes the molding machine body to operate in the next cycle and thereafter. It is characterized in that it is given as an operation stop signal for stopping.

According to a fourth aspect of the present invention, in addition to the requirements of the third aspect, the control means compares the measured gas pressure detected by the gas pressure sensor with a preset set gas pressure. A gas pressure monitoring circuit that outputs a gas pressure abnormality signal when the measured gas pressure exceeds the allowable limit of the set gas pressure,
It is composed of a molding machine control circuit that controls the operation control of the molding machine body, and the gas pressure monitoring circuit is for the molding machine control circuit after the next cycle as long as the measured gas pressure is within the allowable range of the set gas pressure. Outputs an interlock signal that is a condition for continuing operation, while the molding machine control circuit outputs an operation stop signal that causes the molding machine body to stop the operation in the next cycle and thereafter when the interlock signal is not obtained. It is characterized by being

Here, in the invention described in claim 2,
Set the preset gas pressure to 50% of the original pressure on the gas generator side.
The range of 90% to 90% is 50 to 90, which is a range in which the required strength of the mold is satisfied and the mold deformation or the casting surface defect does not occur at the time of casting, and the curing failure of the mold itself does not occur as described later. This is because the range is%.

[0020]

According to the first aspect of the present invention, when the actually measured gas pressure in the gas blowing chamber of the hardening gas is out of the allowable limit of the set gas pressure, a gas pressure abnormality signal is output. In response to this gas pressure abnormality signal, for example, by displaying an alarm of gas pressure abnormality and issuing an alarm such as a buzzer, it is possible to let the workers and others know that there is a high probability that mold curing failure due to gas pressure abnormality has occurred. , The subsequent molding process can be stopped.

According to the second aspect of the present invention, the set gas pressure is set in a range of 50 to 90% of the original pressure on the gas generator side, so that the curing failure including insufficient strength of the mold is overlooked. It will not be lost.

When the gas pressure in the gas blowing chamber is less than 50% of the original pressure, the gas may be defective due to poor sealing between the die and the gas blowing chamber, or poor sealing of the die matching surface of the die itself. When the internal pressure of the chamber does not rise due to leakage, and when the internal pressure of the chamber exceeds 90% of the original pressure, the blow-in port and the exhaust vent hole are blocked by clogging with kneading sand, etc. When the flow rate of ventilation gas is not sufficient,
In either case, defective curing of the mold including insufficient mold strength occurs.

According to the third aspect of the present invention, when the abnormal gas pressure occurs, the main body of the molding machine is provided with an operation stop signal for stopping the operation of the next cycle and thereafter.
The operation of the main body of the molding machine is automatically stopped when the molding work of the current cycle is completed. As a result, it is not necessary to continuously mold the mold while leaving the curing failure.

According to the invention of claim 4, claim 3
Similar to the invention described in (1), when the gas pressure abnormality occurs, the operation of the molding machine main body is automatically stopped, and since the gas pressure monitoring circuit is independent, it can be retrofitted to existing equipment. The function of can be exhibited.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view showing the structure of an embodiment of the present invention, in which parts common to those of the conventional structure shown in FIG.

As shown in FIG. 1, the molding machine main body 20 is controlled by a molding machine control circuit (molding machine control board) 16 so that automatic continuous operation can be performed. On the other hand, in the gas blowing chamber 10. Is equipped with a gas pressure sensor 17 for detecting the internal pressure of the chamber.
The output of 7 is taken into the gas pressure monitoring circuit 18. A predetermined set gas pressure is preset in the gas pressure monitoring circuit 18, and as long as the actually measured gas pressure P ₁ detected by the gas pressure sensor 17 is within the allowable range of the set gas pressure, the gas pressure monitoring circuit 18 18 is a molding machine control circuit 1
For 6, the interlock signal Q, which is a condition for continuing the operation in the next cycle and thereafter, is output. The molding machine control circuit 16 and the gas pressure monitoring circuit 18 constitute control means 19.

Here, the set gas pressure set in the gas pressure monitoring circuit 18 is 50 times the original pressure on the curing gas generator 12 side.
The pressure range is set to 90%. That is, as a result of detailed investigation and analysis by the inventor of the molding state at the time of occurrence of curing failure in gas curing mold molding, as shown in FIG. 2 between the pressure in the gas blowing chamber 10 and the occurrence of curing failure and mold strength. It turns out that there is a strong correlation. The mold strength was evaluated by the penetration strength with a needle pin, and the presence or absence of defective curing was evaluated by visual inspection. As is clear from FIG. 2, when the penetration strength was 1.7 kg or less, the mold strength was insufficient and casting deformation and casting surface defects occurred, and at the same time, when the penetration strength was around 1.6 kg, curing failure occurred. Therefore, the pressure range of the gas blowing chamber 10 capable of ensuring 1.7 kg or more as the intrusion strength of the mold is a pressure range of 50 to 90% of the gas original pressure.

According to the mold making machine constructed as described above, in order to allow the hardening gas to pass through the kneading sand S filled in the mold 1, the hardening gas is hardened in the gas blowing chamber 10 from the hardening gas generator 12 side. When the gas is introduced, the gas pressure in the gas blowing chamber 10 is detected by the gas pressure sensor 17 and taken into the gas pressure monitoring circuit 18.

In the gas pressure monitoring circuit 18, the measured gas pressure P ₁ detected by the gas pressure sensor 17 is compared with a preset set gas pressure, and the measured gas pressure P ₁ is within the allowable range of the set gas pressure. 2), the gas pressure monitoring circuit 18 outputs an interlock signal Q to the molding machine control circuit 16 which is a condition for continuing automatic operation in the next cycle and thereafter. As a result, on the molding machine control circuit 16 side, the condition for continuing the operation after the next cycle is satisfied, and the molding operation of the mold M is continuously performed after the next cycle.

On the other hand, when the measured gas pressure P ₁ detected by the gas pressure sensor 17 exceeds the allowable limit of the set gas pressure, the gas pressure monitoring circuit 18 sends an interlock signal to the molding machine control circuit 16. Q is no longer output. That is, the gas pressure monitoring circuit 18 determines that gas leakage or the like has occurred when the measured gas pressure P ₁ is below the lower limit of the set gas pressure, and similarly the measured gas pressure P ₁ is set to the set gas pressure. When the pressure exceeds the upper limit value, it is judged that the ventilation resistance has increased due to clogging of the gas passage, and in either case, the interlock signal Q is output to the molding machine control circuit 16 at that time. To cancel.

In response to this, on the molding machine control circuit 16 side, the condition for continuing the operation after the next cycle is not satisfied, and the molding machine control circuit 16 outputs an operation stop signal to the molding machine body 20.

As a result, the main body 20 of the molding machine waits for the completion of the molding cycle that is currently in progress, at which point the subsequent operation is stopped, and at the same time, an abnormal display of the pressure inside the gas blowing chamber and an alarm by a buzzer are issued. , Notify nearby workers, etc. of the occurrence of troubles due to abnormal gas pressure. As a result, continuous molding of a defective mold having defects such as poor curing or insufficient strength can be prevented.

Here, in the above embodiment, an example in which the molding machine control circuit 16 and the gas pressure monitoring circuit 18 are independent of each other has been shown. However, the function of the gas pressure monitoring circuit 18 is the molding machine control circuit. Alternatively, the output of the gas pressure sensor 17 may be directly taken into the molding machine control circuit 16 after being applied to the molding machine 16. However, when the present invention is applied to existing equipment, the latter, which can be equipped with the gas pressure monitoring circuit 18, is advantageous in that the equipment can be remodeled on a small scale.

[0034]

As is apparent from the above description, claim 1
According to the invention described in, the gas pressure sensor for detecting the gas pressure in the gas blowing chamber is provided, and the actual gas pressure detected by the gas pressure sensor and the preset gas are compared, When the measured gas pressure exceeds the allowable limit of the set gas pressure, the abnormal gas pressure signal is output.When the abnormal gas pressure signal is received, for example, an alarm of abnormal gas pressure or buzzer is issued. It is possible to stop the subsequent molding process by notifying the occurrence of insufficient curing or insufficient strength of the mold. Therefore, it is possible to prevent outflow of a defective mold due to poor curing or insufficient strength, and it is possible to improve the quality of the mold and reduce the material cost.

According to the second aspect of the present invention, the set gas pressure is set to a pressure range of 50 to 90% of the original pressure on the side of the curing gas generator, whereby the internal pressure of the gas blowing chamber and the mold are set. According to the correlation between the curing failure and the mold strength, in addition to the same effect as the invention according to claim 1, it is possible to determine the mold curing failure and the mold strength insufficient by comparing the measured gas pressure and the set gas pressure. There is an advantage that it can be surely eliminated.

According to the third aspect of the present invention, the abnormal gas pressure signal is given to the molding machine main body as an operation stop signal for stopping the operation of the next and subsequent cycles.
There is an effect that the outflow of the defective mold can be more reliably prevented.

According to the invention as set forth in claim 4, the control means comprises a gas pressure monitoring circuit and a molding machine control circuit for controlling the operation of the molding machine itself, and the gas pressure monitoring circuit actually measures the gas pressure. As long as the gas pressure is within the allowable range of the set gas pressure, it outputs an interlock signal to the molding machine control circuit, which is a condition for continuing operation after the next cycle, while the molding machine control circuit receives the interlock signal. If it is not possible to do so, an operation stop signal is output to the molding machine itself to stop the operation after the next cycle.Therefore, the gas pressure monitoring circuit can be retrofitted when applying it to existing equipment. Has the advantage of being small.

[Brief description of drawings]

FIG. 1 is a structural explanatory view showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a correlation between poor curing of a mold, penetration strength, and gas blowing chamber internal pressure.

FIG. 3 is an operation explanatory view of a conventional gas curing mold making machine when blowing kneading sand.

FIG. 4 is an operation explanatory view of the molding machine shown in FIG. 3 when a curing gas is blown therein.

5 is an operation explanatory view of the molding machine shown in FIG. 3 when the mold is opened.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Mold 6 ... Blowing port 10 ... Gas blowing chamber 12 ... Gas generator 16 ... Molding machine control circuit 17 ... Gas pressure sensor 18 ... Gas pressure monitoring circuit 19 ... Control means 20 ... Molding machine main body M ... Mold S ... Kneading sand

Claims (4)

[Claims] 1. A mold is formed by filling a kneading sand, in which silica sand and a binder have been kneaded in advance, into a mold that has been clamped from the blowing port, and after filling the kneading sand, the blowing port side of the mold. In a gas curing mold making machine, which is configured to cover a gas blowing chamber with the gas blowing chamber and to vent the curing gas from the curing gas generator into the mold through the gas blowing chamber and the blowing port to cure the mold, in the gas blowing chamber. The gas pressure sensor for detecting the gas pressure of the, and the measured gas pressure of the curing gas detected by the gas pressure sensor and the preset set gas pressure are compared, and the measured gas pressure indicates the allowable limit of the set gas pressure. A gas curing mold making machine, comprising: a control unit that outputs a gas pressure abnormal signal when the pressure exceeds the limit. 2. The gas hardening mold making machine according to claim 1, wherein the set gas pressure is set in a pressure range of 50 to 90% of the original pressure on the hardening gas generator side. 3. The gas pressure abnormality signal output from the control means is given to the molding machine main body as an operation stop signal for stopping the operation in the next cycle and thereafter. Alternatively, the gas curing mold making machine according to claim 2. 4. The control means compares a measured gas pressure detected by a gas pressure sensor with a preset set gas pressure, and when the measured gas pressure exceeds an allowable limit of the set gas pressure, It is composed of a gas pressure monitoring circuit that outputs a pressure abnormality signal and a molding machine control circuit that controls the operation of the molding machine body, and in the gas pressure monitoring circuit, the measured gas pressure is within the allowable range of the set gas pressure. As long as the interlock signal is output to the molding machine control circuit, which is a condition for continuing the operation after the next cycle, the molding machine control circuit outputs the interlock signal to the molding machine body when the interlock signal is not obtained. The gas hardening mold making machine according to claim 3, which outputs an operation stop signal for stopping the operation after the cycle.