JP2008213030A - Lost foam casting device, and flask - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lost foam casting device, wherein for a mold removal work in lost foam casting, a casting product can be easily taken out without laying a large-scale dust collector and also without inverting a flask, and simultaneously, the whole of casting sand can be swiftly cooled. <P>SOLUTION: In the lost foam casting device where a lost foam is installed in a flask, the lower part of the flask is provided with a pipe having a filter function, so as to form an air passage, a pressure reduction means is connected to the air passage, and the pressure in the flask is reduced upon pouring, so as to attain the suction of generated gas and the strengthening in the consolidation of casting sand in the flask, the lower part of the flask 1 is provided with an air feeding means 14 injecting compressed air, and the casting sand 2 in the flask 1 is stirred and fluidized. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is a vanishing model casting apparatus and a casting frame.

In the disappearance model casting method using the disappearance model, the operation is generally performed in the following steps.
Disappearance models corresponding to casting products are molded with expanded polystyrene, but this is completed by foaming raw material beads using a pre-foaming machine, molding with a molding machine, and then applying and drying. Is done.
This vanishing model is installed in a state where floor sand is put in a casting frame, and the casting sand is thrown in and the casting sand is hardened by a vibration table. Various types of apparatuses are widely used as the vibration table.

FIG. 7 is a vertical side view of the completed casting frame.
1 is a casting frame (flask), 2 is a casting sand of no binder, 3 is a disappearance model, and 4 is a mortar. Reference numeral 5 denotes a vinyl sheet placed on the casting sand 2 for exhibiting a decompression effect. Reference numeral 6 denotes a pipe-like filter provided at the bottom of the casting frame 1 in order to perform decompression. Reference numeral 7 denotes an expander for protecting the filter 6. The filter 6 forms an air flow path 13, which is connected to a decompression means 9 outside the casting frame 1, that is, for example, a vacuum pump via a vacuum hose 8.

  Thus, in the disappearance model casting method, the casting frame 1 is decompressed using the decompression means 9 at the time of pouring, because the foamed model burns with the pouring and generates a large amount of gas. This is because the state is exhausted, and the pouring sand 2 of the non-binder is maintained in the state of being compactly filled with the vibration table at the time of pouring, so as not to lose its shape.

As such a disappearance model casting method, various proposals have been made for a long time, and examples thereof include the following techniques.
JP-A-6-114496. JP-A-8-1685.

In the disappearance model casting method described above, when the molten metal is poured while decompressing the casting frame 1, the hot water enters while burning the disappearance model 3, and the generated gas is sucked by the decompression means 9.
In this way, pouring can be performed well, but unraveling is performed by reversing the casting frame 1 using a crane (or automatic reversing machine) when the hot water solidifies.
According to such a method, a large amount of dust and hot air is generated, and the casting sand in contact with the casting product is discharged at a high temperature of 400 ° C. to 500 ° C. Must be mixed with cold sand and cooled. Moreover, in order to cope with dust generation, there was a problem that a large hood and a dust collector had to be laid.

  In view of the present situation, the present invention is able to easily remove a cast product without laying a large dust removal device or inverting the cast frame while simultaneously performing the unloading work in the disappearance model casting. The purpose is to be able to cool the whole quickly.

In order to solve the above-mentioned problem, the vanishing model casting apparatus according to the present invention has the vanishing model installed in a casting frame and a pipe having a filter function provided at the lower part of the casting frame as described in claim 1. An air flow path is formed, and decompression means is connected to the air flow path, and the disappearance model casting is designed so as to reduce the pressure of the casting frame during pouring so as to suck the generated gas and strengthen the consolidation of the casting sand in the casting frame. In the device
An air supply means 14 for injecting compressed air into the lower part of the casting frame 1 is provided, and the casting sand 2 of the casting frame 1 is stirred and fluidized.
It is characterized by that.

  Further, in the casting frame according to the present invention, the vanishing model is installed on the casting frame, a pipe having a filter function is provided at the lower part of the casting frame to form an air flow path, and a decompression means is connected to the air flow path. At the time of pouring, the casting frame is decompressed to suck the generated gas and strengthen the consolidation of the casting sand in the casting frame. The casting sand discharge port 17 is provided at the lower part of the casting frame 1 so as to be openable and closable.

As the disappearance model used in the present invention, foamed polystyrene is mainly used. However, an disappearance model made of an optical coin type resin may be used, and other existing disappearance models can be applied.
The compressed air to be injected may be mixed with an inert gas such as nitrogen in addition to the normal atmosphere.

According to the apparatus of the present invention, the unpacking work in the disappearance model casting can be easily performed without laying a large dust removing device and without inverting the casting frame, while simultaneously injecting compressed air. The entire casting sand is mixed and stirred, the casting sand is liquefied, the pressure is released, the casting product can be easily removed, and at the same time, the casting sand can be quickly cooled and post-treated. I came to play.
In addition, according to the casting frame of the present invention, there is an advantage that the casting sand can be easily discharged from the casting frame at the time of releasing the frame.
Other specific effects of the present invention will be apparent from the following description.

In carrying out the present invention, the air supply means 14 is preferably connected to the air flow path 13.
In this way, the existing air flow path (suction) used for casting can be used, and the structure can be simplified.

Moreover, it is good to provide the casting sand discharge port 17 in the lower part of the said casting frame 1 so that opening and closing is possible.
In this way, the liquefied cast sand can be easily discharged while blowing compressed air.

Furthermore, it is preferable that the wind speed of the air to be pumped is 5 m / min to 20 m / min.
By setting such a wind speed, the casting sand can be sufficiently fluidized and stirred, so that the cooling can be performed quickly and the casting product can be easily taken out.

Furthermore, it is preferable that at least one switching valve (15, 16) is provided so that the air supply means 14 also serves as the pressure reducing means 10.
Thereby, the cost of the apparatus can be reduced.
In addition, you may make it ventilate by reversing pressure reduction means 10 (for example, roots type blower).

  In the embodiment of the present invention, the vacuum pump as the decompression means and the blower as the air supply means are used together, but it is of course possible to receive them separately.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal side view of a casting frame in a vanishing model casting apparatus. In the figure, 1 is a casting frame (flask), 2 is cast sand of no binder, 3 is a vanishing model, 4 is , Showing a boiled bowl. Reference numeral 5 denotes a vinyl sheet placed on the casting sand 2 for exhibiting a decompression effect.

As shown in FIGS. 5 and 6, 6 is a pipe-like filter provided at the bottom of the casting frame 1 for decompression, and 7 is an extended band for protecting the filter 6 (FIG. 6). And is disposed immediately above the filter 6.
A discharge port 17 for the casting sand 2 is provided on the opposite side of the bottom of the casting frame 1 from the air supply port 18 to the filter 6, and a plug (plug) is detachably fitted therein. Yes.

  The filter 6 forms an air flow path 13, which is connected to a decompression means 10 (also serving as an air supply means 14) outside the casting frame 1 via a vacuum hose 8, that is, here, a root type blower. Has been. Reference numeral 11 denotes a crane hook for taking out the cast product 12 when the frame is released.

  The piping by the vacuum hose 8 is provided with three-way valves 14 and 15 as switching valves. When suction is performed during casting, the three-way valve 14 opens the atmosphere, and when sending compressed air, the three-way valve 15 is provided. It is configured to be released to the atmosphere.

In this embodiment, an 11 KW roots type blower is used. This Roots type blower is used to achieve the purpose of decompression of the casting frame and air injection (gas exhaust, casting sand flow and cooling) in light of the conditions of the disappearance model and the cast product.
This 11 KW Roots-type blower can send a sufficient air volume to generate the wind speed. That is, when the wind speed is 10 m and the casting frame is a square of 1 m, it is 10 cubic meters / minute.

  The casting frame 1 is decompressed using the decompression means 10 at the time of pouring. The reason is that a large amount of gas is generated by burning the foamed model with pouring, so that it is exhausted. At this time, it is for maintaining the state in which the no-sand casting sand 2 is compactly filled with the vibration table so as not to lose its shape.

Then, the unpacking method of the present invention is carried out as follows.
First, the disappearance model 3 is installed in the casting frame 1 with the floor sand in the state. The cast frame 1 includes a filter 6 and an extract band 7 for protecting the filter 6 at the bottom. The casting frame 1 is filled with casting sand 2 with a vibration table (not shown) or the like, and is brought into a compacted state around the vanishing model 3 (see FIG. 1). Thereafter, the vinyl sheet 5 is put on the upper surface of the casting frame 1.

  In this state, pouring is performed. At that time, the decompression means 10 of the roots type blower is operated, and the three-way valve 14 as a switching valve is opened to the atmosphere (the three-way valve 15 is closed). The inside of the casting frame 1 is evacuated (the vinyl sheet 5 blocks outside air suction), and the molding sand is compacted so that it does not lose its shape during pouring, and the gas generated by burning the disappearing model to the outside The air is sucked and exhausted.

  After about 5 minutes, when the hot water solidifies, the three-way valve 14 is closed, the three-way valve 14 is closed, the three-way valve 15 is opened to the atmosphere, and the pressure reducing means 10 is driven to exert a blowing function. This is operated as the air supply means 14. Then, compressed air is supplied into the inside of the casting frame 1 from the lower part of the casting frame 1 upward through the filter 6.

  At this time, the vinyl sheet 5 is removed in advance. At this time, the flow velocity of air passing through the casting sand 2 is set to about 10 m / min. As a result, the non-binder casting sand 2 flows and is stirred, and the casting is mixed with the thick casting sand 2 in the vicinity of the product and the relatively cold casting sand 2 at a distant position to cause heat exchange to cool the whole. The temperature drops to about 100 ° C. Although this temperature depends on the air volume and the blowing time, it is sufficient that the temperature is 70 ° C. to 130 ° C. Of course, the object of the present invention can be achieved even in the vicinity of this temperature.

The graph of FIG.3 and FIG.4 shows the result of having experimented about making the sand 2 flow by blowing this compressed air into the sand 2 and aiming at temperature fall rapidly.
FIG. 3 shows an experiment in which this method was performed, in which the intermediate portion of the cast sand placed in a predetermined cylindrical container was heated to a higher temperature (180 ° C.) than the cast sand at the upper and lower positions, and then compressed. It is understood that air is sent from below at 10 m / min, and cooling is quick due to the flow and stirring of the casting sand.
FIG. 4 shows the temperature drop when the casting sand is heated under the same conditions and is naturally cooled.
From the comparison between the two, it can be seen that the flow of casting sand due to injection of compressed air and the temperature drop due to mixing are remarkable.

Thereafter, in a state where the casting sand 2 is fluidized and stirred by the compressed air, the cast product 12 is suspended by the crane using the hook 11 and is taken out from the casting frame 1.
Thus, the state in which the casting sand 2 is flowed by the compressed air is a liquefied state, which is equivalent to the absence of accumulated sand pressure, and can be easily pulled out. There is no need to invert the frame 1 and therefore less dust is generated.
Moreover, the cooled casting sand 2 is discharged | emitted outside from the discharge port 17 of the lower part of the casting frame 1 from which the plug 18 was extracted in the state in which compressed air is supplied.

  As described above, when air is injected, the flow path used for pressure reduction during pouring is used as it is, and air is press-fitted through this to prepare and create a flow path for air pressure feeding. There is no need and work is easy.

  The method and apparatus of the present invention can be applied to all casting methods using disappearance models, and its application range is wide.

It is a general | schematic side view of the whole 1 process state of the vanishing model casting apparatus concerning this invention. It is a general | schematic side view of the whole 1 process state of the vanishing model casting apparatus concerning this invention. It is a graph which shows the experimental example concerning the vanishing model casting apparatus concerning this invention. It is a graph which shows the experimental example concerning the vanishing model casting apparatus concerning a prior art. It is a perspective view of the state where the band of the cast frame of the disappearance model casting device concerning the present invention was removed. It is a perspective view in the state where the band of the disappearance model casting device concerning the present invention was loaded. It is a general | schematic longitudinal cross-sectional side view which shows the open frame method for the vanishing model casting concerning a prior art.

Explanation of symbols

1: Casting frame 2: Casting sand 3: Disappearance model 6: Filter 7: Extract band 10: Decompression means 14: Air supply means 17: Discharge port

Claims (6)

The vanishing model is installed in the casting frame, and a pipe having a filter function is provided at the lower part of the casting frame to form an air flow path. A decompression means is connected to the air flow path, and the casting frame is decompressed during pouring. In the disappearance model casting device designed to suction the generated gas and strengthen the consolidation of the casting sand in the casting frame,
An air supply means 14 for injecting compressed air into the lower part of the casting frame 1 is provided, and the casting sand 2 of the casting frame 1 is stirred and fluidized.
A vanishing model casting apparatus characterized by that. The air supply means 14 is connected to the air flow path 13;
The vanishing model casting apparatus according to claim 1. A casting sand discharge port 17 is provided at the bottom of the casting frame 1 so as to be freely opened and closed.
The vanishing model casting apparatus according to claim 1 or 2, characterized in that The wind speed of the air being pumped is 5 m / min to 20 m / min,
The vanishing model casting apparatus according to any one of claims 1 to 3. At least one switching valve (15, 16) is provided, and the air supply means 14 is configured to also serve as the pressure reducing means 10.
The vanishing model casting apparatus according to any one of claims 1 to 4, wherein:   The vanishing model is installed in the casting frame, and a pipe having a filter function is provided at the lower part of the casting frame to form an air flow path. A decompression means is connected to the air flow path, and the casting frame is decompressed during pouring. Then, the generated gas is sucked and the sand of the casting sand in the casting frame is strengthened, and when the frame is released, the casting frame is where compressed air is injected into the casting frame. A casting frame characterized in that the casting sand discharge port 17 is provided to be freely opened and closed.

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