EP0774311A1 - Apparatus and method for producing a core - Google Patents
Apparatus and method for producing a core Download PDFInfo
- Publication number
- EP0774311A1 EP0774311A1 EP96118272A EP96118272A EP0774311A1 EP 0774311 A1 EP0774311 A1 EP 0774311A1 EP 96118272 A EP96118272 A EP 96118272A EP 96118272 A EP96118272 A EP 96118272A EP 0774311 A1 EP0774311 A1 EP 0774311A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- air
- core space
- introducing
- gas
- molding sand
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C15/00—Moulding machines characterised by the compacting mechanism; Accessories therefor
- B22C15/23—Compacting by gas pressure or vacuum
- B22C15/24—Compacting by gas pressure or vacuum involving blowing devices in which the mould material is supplied in the form of loose particles
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C9/00—Moulds or cores; Moulding processes
- B22C9/12—Treating moulds or cores, e.g. drying, hardening
- B22C9/123—Gas-hardening
Definitions
- This invention relates to an apparatus and method for producing a core with gas-curable molding sand.
- a method and apparatus for producing a core is conventionally known wherein gas-curable molding sand is charged into a core space by the air-blowing method, and is then cured by curing gas introduced into the space.
- Japanese Patent Publication No. 48 - 13804 discloses such an apparatus. It has a core box having a cope and a drag to mate each other to define a core space therebetween. The cope is fixedly mounted on a frame, and the drag is supported by a cylinder for vertical movement to and away from the fixed cope. An assembly of a gassing means, a blow head, and a core-pushing mechanism is disposed above the core box. The assembly is horizontally slidable on the frame through wheels such that it mates the upper portion of the cope to supply an air blow and curing gas into the core space.
- the purpose of this invention is to provide an apparatus and method for producing a core having a high density wherein the number of vent plugs to be used and cost and time to produce a metal mold are reduced.
- be method of the present invention for producing a core includes the steps of charging gas-curable molding sand into the core space, reducing the pressure of the core space to 2 - 100 Torr, introducing from above an air flow into the core space at a rate that increases the pressure of the core space at 50 - 600 Kg/cm 2 /sec to apply pressure to the upper surface of the gas-curable molding sad to give it a high density, and introducing curing gas into the core space to harden the molding sand.
- the apparatus of the present invention is one of the type disclosed in Japanese Patent Publication No. 48 - 13804. However, in be apparatus of the present invention there is evacuating means to reduce the pressure of the core space.
- the apparatus includes a blow head, pressure chamber, core halves to define a core space therebetween, evacuating means to reduce the pressure of the core space, a valve for air-blowing, a valve for introducing air, means for introducing curing gas, and means for discharging the curing gas.
- an air flow is suddenly introduced into the evacuated core space.
- This introduced air flow applies an impulse pressure to be upper surface of the molding sand, and therefore it is consolidated to a higher density than an upper surface that is consolidated only by air-blowing.
- a plurality of columns 2 are mounted on the base 1, and a frame F is mounted on the top of the columns 2.
- a sand hopper 4 having a sand feeding gate 3, and an air-introducing means having a valve 5 for air-blowing, a valve 6 for introducing air, and an air tank 7.
- a blow head 10 is mounted on the frame below the sand hopper 4.
- the blow head 10 has a port 8 for receiving gas-curable molding sand S from the hopper 4 and introducing compressed air 10 into the blow head.
- the blow head 10 is moved horizontally along the frame F so that it communicates with the air-blowing valve 5.
- a pressure chamber 11 is horizontally spaced apart from and connected to the blow head 10 so that the assembled pressure chamber and the blow head are moved horizontally along the frame by a cylinder 12 connected to the pressure chamber 11.
- the pressure chamber 11 communicates with the air-introducing valve 6 at the top and sealingly meets the top of a metal cope 13a or metal mold half at the bottom.
- the metal cope 13a is mounted on the columns 2 such that it can move up from its position shown in Fig. 2.
- a lifter table T is disposed between the lower parts of the columns 2.
- the lifter table T supports a metal drag or metal mold half 13b on the top of the table T.
- the cope and drag or mold halves define a core space 14 between them.
- a plurality of apertures 13c for air-blowing are formed in the cope 13a. These apertures 13c communicate with blow nozzles 9 formed in the bottom of the blow head 10.
- vent plugs 16 fit in vent holes 15 formed in the cope 13a and drag 13b.
- the vent holes 15 communicate with a vacuum pump P or evacuating means 18, which evacuates the core space 14.
- One end of the evacuating means 18 communicates with the upper and lower parts of the core space 14 through the bottom of the pressure chamber 11, the wall of the lifter table 4, and vent holes 15, while the other end communicates with the vacuum pump P through an evacuating valve 17.
- the pump P reduces the pressure of the core space 14 to a pressure of 2 - 100 Torr.
- vent holes 15 of the pressure chamber 11 and cope 13a communicate with means 19 for introducing curing gas from a gas generator 19 into the core space 14 through a valve 22.
- the vent holes 15 of the drag 13b communicate with a curing-gas-discharging means 21 through the lifter table T and a valve 23.
- the gas-curable molding sand S which has been previously mixed at a location (not shown), is placed into the hopper 4.
- the amount of the molding sand in the hopper which is more than one shot for the core space, is then fed into the blow head 10 when the sand feeding gate 3 is opened.
- the assembly of the blow head 10 and pressure chamber 11 are moved laterally by the cylinder 12 until the blow head 10 is located just above the mold halves and lifter table T (Fig. 2).
- the port 8 is connected to a port 8a of the valve 6.
- the lifter table T is then moved up with the drag 13b until the drag 13b mates and pushes up the cope 13a so that the blow nozzles 9 engage and communicate with the apertures 13c of the cope 13a.
- the lifter table T is locked at that position. (This state is shown in Fig. 3 of the second embodiment of the present invention.)
- the air-blowing then starts.
- compressed air from the air tank 7 is introduced into the blow head 10.
- the air blown into the blow head 10 and the molding sand in it flow together through the nozzles 9 into the core space 14, so that the molding sand accumulates in the core space 14 and the air is discharged through the vent plugs 16.
- the location of these vent plugs can be determined by just considering their proper venting. Arranging them for a good consolidation of the molding sand need not be considered.
- the lifter table T is then lowered until the cope 13a returns to its original lower position shown in Fig. 2, where the cope 13a is separated from the blow head 10.
- the assembly 10, 11 is moved to its original position shown in Fig. 1.
- the lifter table T is then moved up until air supply holes 11a of the pressure chamber 11 engage and communicate with the apertures 13c of the cope 13a.
- the core space 14 is evacuated by opening the valve 23 so that the pressure of the core space becomes 2 - 100 Torr.
- the location of the vent plugs 16 can be determined by just considering their proper venting, and a good consolidation need not be considered.
- the valve 6 is then opened, so that an air flow is suddenly introduced into the core space 14.
- the flow applies an impulse pressure to the surface of the molding sand in the core space, so that the molding sand S is well consolidated.
- it has a charging density higher than that when it is subjected only to the air blow.
- Curing gas from the curing-gas-introducing means 20 is then introduced into the core space 14.
- the gas passes through the molding sand S, so that it is hardened.
- Purging is then carried out, if necessary.
- the lifter table T is lowered, while upper and lower pushers 25, 25 are operated to push and take out the core product.
- binders such as a water glass, phenol resin, polyurethane resin, furan resin, etc. are used for gas-curable molding sand.
- curing gases such as carbon dioxide, TEA gas, sulfur dioxide, methyl formate, etc. may be used.
- the air is introduced into the pressure chamber such that the pressure in the chamber is increased at a rate of 50 - 600 kg /cm 2 /sec. More preferably the rate is 200 - 400 kg /cm 2 /sec.
- the air to be introduced may be ambient air of the atmosphere or compressed air. When compressed air is used, its pressure is preferably 10 kg/cm 2 at maximum. The pressure may be optimized depending on the size and shape of the air-introducing valve.
- Figs. 1 and 2 The above embodiment shown in Figs. 1 and 2 is exemplary only. Clearly to one skilled in the art some modification may be made to the embodiment.
- the evacuating means 18 communicates with the core space at its upper and lower parts, it may be modified to communicate with the space at both sides of it.
- vertical mold halves may be used instead of using a cope and a drag. The mold halves may be opened and closed by one or more cylinders that extend horizontally.
- the blow head 10 and pressure chamber 11, which in the embodiment are connected, may, alternatively, be separated and moved separately.
- the molding sand S is charged into the core space by air-blowing.
- This charge can be done using the gravity of the sand or using a vacuum.
- the molding sand is charged into it due to the pressure difference between the blow head 10 and the vacuum.
- the blow head 10 acts as a pressure chamber like the pressure chamber 11.
- the pressure chamber 11 can be eliminated.
- either the air-blowing valve 5 or air-introducing valve 6 may be also eliminated.
- Fig. 3 shows a second embodiment of the apparatus of the invention. In it the same reference numbers are designated for the same elements as in Figs. 1 and 2.
- the apparatus includes a frame F secured to columns 2 mounted on a base 1, the same as in Figs. 1 and 2.
- a sand hopper 4 which has a sand-feeding gate 3, and an air-introducing mean, which has an air-introducing valve 6 and air tank 7, are mounted on the frame F.
- a hollow cylindrical connecting body H is disposed under the hopper 4.
- the connecting body H has a port 8 to receive molding sand from the hopper and a port 8b through which air is introduced into the connecting body H.
- Under the connecting body H a pressure chamber 31 having nozzles 9 is disposed.
- the pressure chamber 31 and the connecting body H are integrally fixed to each other and they move integrally.
- the port 8b is opened and closed by a valve 6.
- a gas chamber 32 is connected to the pressure chamber 31 so that the assembled gas chamber and pressure chamber are horizontally moved along the frame F by a cylinder 12.
- the gas chamber 32 communicates with a gas generator 19.
- a pusher 25 having pushing pins is disposed within the gas chamber.
- the gas chamber 32 sealingly meets a metal mold half or cope 13a when moved onto it.
- a sand-containing box B is disposed. Since this box B has a turner R, it can drop the molding sand contained in it into the pressure chamber 31 when turned over by the turner R.
- a sand-measuring means having a belt conveyor measures the molding sand of one shot by controlling the operation of the belt conveyor and the period that the sand-feeding gate 3 is opened.
- the gate 3 is then closed, and a core space 14 is evacuated by evacuating means 18 to a pressure of 2 - 100 Torr.
- evacuating means 18 to a pressure of 2 - 100 Torr.
- the air-introducing valve 6 is then opened to apply compressed air to the pressure chamber 31.
- the pressure of the compressed air is preferably 10 kg/cm 2 at maximum, and the rate of the air pressure that increases in the core space is preferably 50 - 600 kg /cm 2 /sec.
- the air flow and molding sand in the pressure chamber flow into the core space 14. The air flow goes out through the vent plugs 16, and the molding sand is consolidated in the core space 14. It is consolidated to a higher density than the initial density due to just the vacuum.
- the gas chamber 32 is then connected to the mold halves in a way similar to the embodiment of Figs. 1 and 2. Similarly, the molding sand is cured and taken out from the mold halves by upper and lower pushers.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Power Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Molds, Cores, And Manufacturing Methods Thereof (AREA)
- Casting Devices For Molds (AREA)
Abstract
A method is disclosed of producing a highly consolidated sand core. The method includes the steps of closing metal mold halves (13a, 13b) to define a core space (14), charging gas-curable molding sand into the mold space, evacuating the core space to a pressure of 2 - 100 Torr, introducing air into the evacuated core space at an air pressure that increases at a rate of 50 - 600 kg/cm2 /sec to apply a pressure to the surface of the gas-curable molding sand to obtain a high charging density; and introducing a curing gas into the core space to harden the molding sand.
Description
- This invention relates to an apparatus and method for producing a core with gas-curable molding sand.
- A method and apparatus for producing a core is conventionally known wherein gas-curable molding sand is charged into a core space by the air-blowing method, and is then cured by curing gas introduced into the space. For example, Japanese Patent Publication No. 48 - 13804 discloses such an apparatus. It has a core box having a cope and a drag to mate each other to define a core space therebetween. The cope is fixedly mounted on a frame, and the drag is supported by a cylinder for vertical movement to and away from the fixed cope. An assembly of a gassing means, a blow head, and a core-pushing mechanism is disposed above the core box. The assembly is horizontally slidable on the frame through wheels such that it mates the upper portion of the cope to supply an air blow and curing gas into the core space.
- However, since in the conventional apparatus molding sand is consolidated only by air-blowing, part of the molding sand in the core space cannot be well consolidated due to the differing capabilities among a plurality of blowing nozzles when a cope that has many nozzles is used.
- Accordingly, it is necessary to predict how air flows during air-blowing, and many air-discharge ports such as vent plugs must be adequately disposed in the metal mold for air-blowing.
- Further, to optimize the number and location of the vent plugs, some trial blowing must be repeated to evaluate the roughness of the surface and density of the molding sand of the core products, and the metal mold must be modified. Thus, to complete a metal mold takes a lot of time and costs.
- The purpose of this invention is to provide an apparatus and method for producing a core having a high density wherein the number of vent plugs to be used and cost and time to produce a metal mold are reduced.
- To the above end, in one aspect be method of the present invention for producing a core includes the steps of charging gas-curable molding sand into the core space, reducing the pressure of the core space to 2 - 100 Torr, introducing from above an air flow into the core space at a rate that increases the pressure of the core space at 50 - 600 Kg/cm2/sec to apply pressure to the upper surface of the gas-curable molding sad to give it a high density, and introducing curing gas into the core space to harden the molding sand.
- The apparatus of the present invention is one of the type disclosed in Japanese Patent Publication No. 48 - 13804. However, in be apparatus of the present invention there is evacuating means to reduce the pressure of the core space. In one aspect the apparatus includes a blow head, pressure chamber, core halves to define a core space therebetween, evacuating means to reduce the pressure of the core space, a valve for air-blowing, a valve for introducing air, means for introducing curing gas, and means for discharging the curing gas.
- The other aspects of the apparatus and the method of the invention will be understood from the below embodiments and attached claims.
- According to the present invention, an air flow is suddenly introduced into the evacuated core space. This introduced air flow applies an impulse pressure to be upper surface of the molding sand, and therefore it is consolidated to a higher density than an upper surface that is consolidated only by air-blowing.
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- Fig. 1 is a cross-sectional view of a first embodiment of the apparatus of the present invention.
- Fig. 2, which is like Fig. 1, is a cross-sectional view of the first embodiment.
- Fig. 3 is a cross-sectional view of a second embodiment of the apparatus of the present invention.
- Now the embodiments of the apparatus of the present invention will be explained by reference to the drawings. The first embodiment is shown in Figs. 1 and 2, and the second in Fig. 3.
- In Fig. 1 a plurality of
columns 2 are mounted on thebase 1, and a frame F is mounted on the top of thecolumns 2. On the frame F are mounted asand hopper 4 having asand feeding gate 3, and an air-introducing means having avalve 5 for air-blowing, avalve 6 for introducing air, and anair tank 7. - A
blow head 10 is mounted on the frame below thesand hopper 4. Theblow head 10 has aport 8 for receiving gas-curable molding sand S from thehopper 4 and introducingcompressed air 10 into the blow head. Theblow head 10 is moved horizontally along the frame F so that it communicates with the air-blowingvalve 5. - A
pressure chamber 11 is horizontally spaced apart from and connected to theblow head 10 so that the assembled pressure chamber and the blow head are moved horizontally along the frame by acylinder 12 connected to thepressure chamber 11. Thepressure chamber 11 communicates with the air-introducingvalve 6 at the top and sealingly meets the top of ametal cope 13a or metal mold half at the bottom. Themetal cope 13a is mounted on thecolumns 2 such that it can move up from its position shown in Fig. 2. - A lifter table T is disposed between the lower parts of the
columns 2. The lifter table T supports a metal drag ormetal mold half 13b on the top of the table T. The cope and drag or mold halves define acore space 14 between them. A plurality ofapertures 13c for air-blowing are formed in thecope 13a. Theseapertures 13c communicate withblow nozzles 9 formed in the bottom of theblow head 10. - A plurality of
vent plugs 16 fit invent holes 15 formed in thecope 13a and drag 13b. Thevent holes 15 communicate with a vacuum pump P or evacuating means 18, which evacuates thecore space 14. One end of the evacuating means 18 communicates with the upper and lower parts of thecore space 14 through the bottom of thepressure chamber 11, the wall of the lifter table 4, and ventholes 15, while the other end communicates with the vacuum pump P through an evacuatingvalve 17. The pump P reduces the pressure of thecore space 14 to a pressure of 2 - 100 Torr. - Further, the
vent holes 15 of thepressure chamber 11 and cope 13a communicate withmeans 19 for introducing curing gas from agas generator 19 into thecore space 14 through avalve 22. Thevent holes 15 of thedrag 13b communicate with a curing-gas-discharging means 21 through the lifter table T and avalve 23. - In the operation of the apparatus of Fig. 1, the gas-curable molding sand S, which has been previously mixed at a location (not shown), is placed into the
hopper 4. The amount of the molding sand in the hopper, which is more than one shot for the core space, is then fed into theblow head 10 when thesand feeding gate 3 is opened. - The assembly of the
blow head 10 andpressure chamber 11 are moved laterally by thecylinder 12 until theblow head 10 is located just above the mold halves and lifter table T (Fig. 2). Theport 8 is connected to a port 8a of thevalve 6. - The lifter table T is then moved up with the
drag 13b until thedrag 13b mates and pushes up thecope 13a so that theblow nozzles 9 engage and communicate with theapertures 13c of thecope 13a. The lifter table T is locked at that position. (This state is shown in Fig. 3 of the second embodiment of the present invention.) - The air-blowing then starts. When the
blow valve 5 is opened, compressed air from theair tank 7 is introduced into theblow head 10. The air blown into theblow head 10 and the molding sand in it flow together through thenozzles 9 into thecore space 14, so that the molding sand accumulates in thecore space 14 and the air is discharged through thevent plugs 16. The location of these vent plugs can be determined by just considering their proper venting. Arranging them for a good consolidation of the molding sand need not be considered. - The lifter table T is then lowered until the
cope 13a returns to its original lower position shown in Fig. 2, where thecope 13a is separated from theblow head 10. Theassembly pressure chamber 11 engage and communicate with theapertures 13c of thecope 13a. Thecore space 14 is evacuated by opening thevalve 23 so that the pressure of the core space becomes 2 - 100 Torr. As was explained above, the location of thevent plugs 16 can be determined by just considering their proper venting, and a good consolidation need not be considered. - The
valve 6 is then opened, so that an air flow is suddenly introduced into thecore space 14. The flow applies an impulse pressure to the surface of the molding sand in the core space, so that the molding sand S is well consolidated. Thus it has a charging density higher than that when it is subjected only to the air blow. - Curing gas from the curing-gas-introducing
means 20 is then introduced into thecore space 14. The gas passes through the molding sand S, so that it is hardened. Purging is then carried out, if necessary. The lifter table T is lowered, while upper andlower pushers - Preferably, for gas curing, binders such as a water glass, phenol resin, polyurethane resin, furan resin, etc. are used for gas-curable molding sand. For such gas-curable molding sand, curing gases such as carbon dioxide, TEA gas, sulfur dioxide, methyl formate, etc. may be used.
- Preferably the air is introduced into the pressure chamber such that the pressure in the chamber is increased at a rate of 50 - 600 kg /cm2 /sec. More preferably the rate is 200 - 400 kg /cm2 /sec. The air to be introduced may be ambient air of the atmosphere or compressed air. When compressed air is used, its pressure is preferably 10 kg/cm2 at maximum. The pressure may be optimized depending on the size and shape of the air-introducing valve.
- The above embodiment shown in Figs. 1 and 2 is exemplary only. Clearly to one skilled in the art some modification may be made to the embodiment. For example, although in the device of Figs. 1 and 2 the evacuating
means 18 communicates with the core space at its upper and lower parts, it may be modified to communicate with the space at both sides of it. Further, instead of using a cope and a drag, vertical mold halves may be used. The mold halves may be opened and closed by one or more cylinders that extend horizontally. Theblow head 10 andpressure chamber 11, which in the embodiment are connected, may, alternatively, be separated and moved separately. - Further, in the above embodiment the molding sand S is charged into the core space by air-blowing. This charge can be done using the gravity of the sand or using a vacuum. When a vacuum is used in the
core space 14, the molding sand is charged into it due to the pressure difference between theblow head 10 and the vacuum. Accordingly, for this case theblow head 10 acts as a pressure chamber like thepressure chamber 11. Thus thepressure chamber 11 can be eliminated. Further, either the air-blowingvalve 5 or air-introducingvalve 6 may be also eliminated. - Fig. 3 shows a second embodiment of the apparatus of the invention. In it the same reference numbers are designated for the same elements as in Figs. 1 and 2.
- In Fig. 3 the apparatus includes a frame F secured to
columns 2 mounted on abase 1, the same as in Figs. 1 and 2. Asand hopper 4, which has a sand-feedinggate 3, and an air-introducing mean, which has an air-introducingvalve 6 andair tank 7, are mounted on the frame F. - A hollow cylindrical connecting body H is disposed under the
hopper 4. The connecting body H has aport 8 to receive molding sand from the hopper and a port 8b through which air is introduced into the connecting body H. Under the connecting body H apressure chamber 31 havingnozzles 9 is disposed. Thepressure chamber 31 and the connecting body H are integrally fixed to each other and they move integrally. The port 8b is opened and closed by avalve 6. Agas chamber 32 is connected to thepressure chamber 31 so that the assembled gas chamber and pressure chamber are horizontally moved along the frame F by acylinder 12. Thegas chamber 32 communicates with agas generator 19. Apusher 25 having pushing pins is disposed within the gas chamber. Thegas chamber 32 sealingly meets a metal mold half or cope 13a when moved onto it. - Midway in the connecting body H a sand-containing box B is disposed. Since this box B has a turner R, it can drop the molding sand contained in it into the
pressure chamber 31 when turned over by the turner R. - A sand-measuring means having a belt conveyor measures the molding sand of one shot by controlling the operation of the belt conveyor and the period that the sand-feeding
gate 3 is opened. - Other components of the apparatus, such as a lifter table T, curing-gas-introducing
means 20, etc. are substantially the same as those in Figs. 1 and 2. - In operation, when the
gate 3 is opened, an amount (corresponding to one shot) of gas-curable molding sand S from thehopper 4 is dropped into the connecting body H. Part of the molding sand is caught by the sand-containing box B, and the remaining part accumulates on the bottom of thepressure chamber 32, while the lifter table T, which carries a metal drag ormold half 13b, starts to move up until thenozzles 9 fit inholes 13c of the cope 13a. - The
gate 3 is then closed, and acore space 14 is evacuated by evacuatingmeans 18 to a pressure of 2 - 100 Torr. By this evacuation, part of the molding sand in thepressure chamber 31 is charged into the core space, and this charged molding sand is to some degree consolidated (initial degree or initial density). - The air-introducing
valve 6 is then opened to apply compressed air to thepressure chamber 31. The pressure of the compressed air is preferably 10 kg/cm2 at maximum, and the rate of the air pressure that increases in the core space is preferably 50 - 600 kg /cm2 /sec. The air flow and molding sand in the pressure chamber flow into thecore space 14. The air flow goes out through the vent plugs 16, and the molding sand is consolidated in thecore space 14. It is consolidated to a higher density than the initial density due to just the vacuum. - These evacuations and air flows are repeated to further consolidate the molding sand. Immediately before the final air flow, the sand-containing box B is turned over to drop the sand in it onto the bottom of the
pressure chamber 31. - After the final air-blowing, the
gas chamber 32 is then connected to the mold halves in a way similar to the embodiment of Figs. 1 and 2. Similarly, the molding sand is cured and taken out from the mold halves by upper and lower pushers.
Claims (15)
- A method of producing a core, comprising the steps of:closing metal mold halves to define a core space therebetween;charging gas-curable molding sand into the mold space;evacuating the core space to a pressure of 2 - 100 Torr;introducing an air flow into the evacuated core space at an air-pressure rate that increases at 50 - 600 kg /cm2 /sec to apply a pressure to the surface of the gas-curable molding sand to obtain a high charging density; andintroducing a curing gas into the core space to harden the molding sand.
- The method of claim 1, wherein the gas-curable molding sand is charged into the mold space by air-blowing.
- The method of claim 1, wherein the gas-curable molding sand is charged into the mold space by using a vacuum.
- The method of claim 1, wherein the air introduced into the evacuated core space is at atmospheric pressure.
- The method of claim 1, wherein the air introduced into the evacuated core space is compressed air.
- The method of claim 1, further comprising a step of again evacuating the core space between the steps of introducing an air flow into the core space and introducing a curing gas into the core space.
- An apparatus for producing a core by introducing gas-curable molding sand into a core space defined by a closed metal cope and drag, comprising:a blow head (10) for receiving gas-curable molding sand, the blow head having an air-introducing port (8) at an upper part thereof and blow nozzles (9) at a lower part thereof;a movable pressure chamber (11) to sealingly engage an upper part of the cope (13a) which has holes in the upper part;evacuating means (18) for evacuating the core space (14);a blow valve (5) for introducing air into the blow head;an air-introducing valve (6) for introducing air into the pressure chamber (11);curing-gas-introducing means (20) for introducing curing gas into the core space;a curing-gas-discharging means (21) for discharging the curing gas from the core space; anda lifter table (T) to vertically move the cope and drag.
- An apparatus for producing a core by introducing gas-curable molding sand into a core space defined by a closed metal cope and drag which are closed by metal-mold-closing means that includes a lifter table disposed between columns, comprising:a blow head (10) provided with an air-introducing port (8) at an upper part thereof and blow nozzles (9) at a lower part thereof for receiving and feeding the gas-curable molding sand into the core space, the blow head being movable below a frame (F) mounted on upper parts of the columns and positioned below a sand hopper (4);a blow valve (5) mounted on the frame (F) for introducing air into the blow head through the air-introducing port (8);means (18) for evacuating the core space;means (20) for introducing curing gas into the core space; andmeans (21) for discharging the curing gas from the core space.
- The apparatus of claim 8, wherein the apparatus further comprises a pressure chamber 11 connected to the blow head (10) and sealingly engaged with the upper part of the metal cope (13a) and an air-introducing valve (6) mounted on the frame for introducing air into the pressure chamber (11).
- A method of producing a core, comprising the steps of:closing metal mold halves by means for closing and opening the mold halves so as to define a core space within the mold halves;dropping a measured amount of gas-curable molding sand into a pressure chamber that communicates with an upper part of the core space;evacuating the core space to a pressure of 2 - 100 Torr;introducing air into the evacuated core space one or more times at an air pressure that increases at a rate of 50 - 600 kg /cm2 /sec to apply a pressure to the surface of the gas-curable molding sand to obtain a high charging density; andintroducing a curing gas into the core space to harden the molding sand.
- The method of claim 10, wherein the introduced air is at atmospheric pressure.
- The method of claim 10, wherein the introduced air is compressed air.
- The method of claim 10, wherein the air is introduced through the pressure chamber.
- The method of claim 14, further comprising a step of again evacuating the core space before the step of introducing a curing gas into the core space to harden the molding sand.
- An apparatus for producing a core by charging gas-curable molding sand into a core space defined in closed metal mold halves (13a, 13b) which are closed by means for closing and opening the mold halves, comprising:measuring means for measuring an amount of one shot of the molding sand S;a pressure chamber (31) disposed below the measuring means, the pressure chamber having an air-introducing port (6) and a sand-receiving port (8) at an upper part thereof and having sand-introducing nozzles (9) at a lower part thereof so as to receive and feed the gas-curable molding sand (S);a gas chamber (32) movable to sealingly engage the upper part of one of the metal mold halves (13a) which has holes in the upper part;evacuating means (18) for evacuating the core space;an air-introducing valve (6) for introducing air into the core space;means (20) for introducing a curing gas into the core space;means (21) for discharging the curing gas from the core space; anda lifter table (T) for vertically moving the mold halves.
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP32366095A JP3322382B2 (en) | 1995-11-17 | 1995-11-17 | Core molding method and apparatus |
JP323660/95 | 1995-11-17 | ||
JP8061985A JPH09225583A (en) | 1996-02-23 | 1996-02-23 | Method for molding core and apparatus therefor |
JP61985/96 | 1996-02-23 |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0774311A1 true EP0774311A1 (en) | 1997-05-21 |
Family
ID=26403062
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP96118272A Withdrawn EP0774311A1 (en) | 1995-11-17 | 1996-11-14 | Apparatus and method for producing a core |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0774311A1 (en) |
KR (1) | KR970029928A (en) |
CN (1) | CN1159374A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
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CN102078933A (en) * | 2010-12-24 | 2011-06-01 | 山西华德冶铸有限公司 | Automatic mould assembling device |
CN102632203A (en) * | 2012-05-07 | 2012-08-15 | 苏州明志科技有限公司 | Core manufacturing method of cold core |
DE102016123050A1 (en) | 2016-11-29 | 2018-05-30 | HÜTTENES-ALBERTUS Chemische Werke Gesellschaft mit beschränkter Haftung | Method for producing cores or molds for metal casting |
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CN1075965C (en) * | 1998-05-19 | 2001-12-12 | 北京中租铸造模具技术开发公司 | Simple vacuum model producing line |
DE10144193C1 (en) * | 2001-09-08 | 2002-10-31 | Vaw Mandl & Berger Gmbh Linz | Production of molded parts involves pouring a molding material into a molding tool in an injection molding machine |
CN102310166B (en) * | 2011-10-19 | 2012-12-26 | 华东泰克西汽车铸造有限公司 | Production technology of sand core in oil duct of automobile engine block |
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CN103192032B (en) * | 2013-04-22 | 2016-04-06 | 山东建筑大学 | A kind of water-glass sand CO 2negative pressure air blowing hardening process |
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CN103551519A (en) * | 2013-11-14 | 2014-02-05 | 邵宏 | Manufacturing method of non-drop-sand mud core and spraying device |
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CN105108067B (en) * | 2015-08-31 | 2017-08-25 | 宁夏共享模具有限公司 | It is a kind of to lift the method that explosion core mould fills sand shaping |
CN106077523B (en) * | 2016-08-24 | 2018-11-16 | 苏州苏铸成套装备制造有限公司 | One kind, which vacuumizes, penetrates sand structure |
CN109396353B (en) * | 2018-12-24 | 2020-09-29 | 沈阳汇亚通铸造材料有限责任公司 | CO blowing of sodium silicate sand for casting2Hardening method |
CN113333687B (en) * | 2021-05-18 | 2022-08-09 | 苏州明志科技股份有限公司 | Core making method and device of large sand core |
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EP0123756A1 (en) * | 1983-04-27 | 1984-11-07 | Naniwa Products Co, Ltd | Entirely automatic, cold box type machine for molding an integral connecting core |
EP0443287A2 (en) * | 1990-02-23 | 1991-08-28 | Naniwa Products Co, Ltd | A horizontally parted molding machine of stationary drag core box type |
DE9315614U1 (en) * | 1993-10-08 | 1993-12-23 | Adolf Hottinger Maschinenbau Gmbh, 68219 Mannheim | Device for filling shot heads |
-
1996
- 1996-11-14 EP EP96118272A patent/EP0774311A1/en not_active Withdrawn
- 1996-11-15 CN CN96123401A patent/CN1159374A/en active Pending
- 1996-11-18 KR KR1019960054788A patent/KR970029928A/en not_active Application Discontinuation
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
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JPS4813804B1 (en) | 1968-04-27 | 1973-05-01 | ||
EP0123756A1 (en) * | 1983-04-27 | 1984-11-07 | Naniwa Products Co, Ltd | Entirely automatic, cold box type machine for molding an integral connecting core |
EP0443287A2 (en) * | 1990-02-23 | 1991-08-28 | Naniwa Products Co, Ltd | A horizontally parted molding machine of stationary drag core box type |
DE9315614U1 (en) * | 1993-10-08 | 1993-12-23 | Adolf Hottinger Maschinenbau Gmbh, 68219 Mannheim | Device for filling shot heads |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102078933A (en) * | 2010-12-24 | 2011-06-01 | 山西华德冶铸有限公司 | Automatic mould assembling device |
CN102632203A (en) * | 2012-05-07 | 2012-08-15 | 苏州明志科技有限公司 | Core manufacturing method of cold core |
DE102016123050A1 (en) | 2016-11-29 | 2018-05-30 | HÜTTENES-ALBERTUS Chemische Werke Gesellschaft mit beschränkter Haftung | Method for producing cores or molds for metal casting |
WO2018099894A1 (en) | 2016-11-29 | 2018-06-07 | HÜTTENES-ALBERTUS Chemische Werke Gesellschaft mit beschränkter Haftung | Method for producing cores or molds for metal casting |
Also Published As
Publication number | Publication date |
---|---|
CN1159374A (en) | 1997-09-17 |
KR970029928A (en) | 1997-06-26 |
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