CA1183320A - Method of producing frozen casting moulds - Google Patents
Method of producing frozen casting mouldsInfo
- Publication number
- CA1183320A CA1183320A CA000380444A CA380444A CA1183320A CA 1183320 A CA1183320 A CA 1183320A CA 000380444 A CA000380444 A CA 000380444A CA 380444 A CA380444 A CA 380444A CA 1183320 A CA1183320 A CA 1183320A
- Authority
- CA
- Canada
- Prior art keywords
- binder material
- mould
- frozen
- cooled
- binder
- 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.)
- Expired
Links
Classifications
-
- 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
- B22C9/126—Hardening by freezing
Abstract
ABSTRACT OF THE DISCLOSURE
To produce frozen casting moulds or core boxes the binder is cooled till freezing at least partly before or during the moulding process. This allows the production rate to be increased to such a level that the working rate of automatic machines for the production of casting moulds and core boxes can be fully obtained.
To produce frozen casting moulds or core boxes the binder is cooled till freezing at least partly before or during the moulding process. This allows the production rate to be increased to such a level that the working rate of automatic machines for the production of casting moulds and core boxes can be fully obtained.
Description
27521-1 ~ ~ ~ ~ ~
The inven-tion relates to a method oE producing frozen casting moulcls or cores of a granular material and a binder in a mould chamber or a core box, comprising the use of a Ereezable binder which is in a gas or liquid state a-t posi-tive temperatures calculated in degrees cen-tigrade.
The specification of the IJni-ted States Patent 4,150,70 -teaches a method in which the mould sand is admixed with a controlled quantity of water which after moulding is frozen to iee in a certain depth from the surface tha-t is caused to eontaet molten metal e.g. by placing a layer of so-called dry ice or spraying liquid nitrogen on the surface. This gives a very strong mould surface which retains its strength and shape until the surface of the metal has solidified. As the metal gives off its heat, the water melts and evaporates so that the mould begins collapsing without the use of mechanical means, practically no srnoke is developed in the casting process, and the mould sand can be reused right away.
An article in the Russian Magazine Liteinoe Proizvodsto, 1975, No. 5, P.21-22, describes the freezing of a sand mould containing 3 to 7 percent water by means of a coolan-t that circulates through the evaporator in a cooling system and through mould.
Freezing of the added water is by nature a rather slow process r and consequently it takes a relatively long time from the moment when the moulding process is finished until the mould has frozen deep enough to be able to resist the effect of molten metal for a sufficien-tly long time, and this in -turn causes the overall mould procduction to become considerably more time-consuming " v'l~
~833~
than the convellti.ona:L moulcl manufact-lring processes.
The object Or the inven-tion is to overcome -this drawback of the known embod.iments of -the presen-t methocl, and -this objec-t is achieved by the present inven-tion. Thus -the presen-t inventior provides a method of producing frozen casting moulds or cores, which method comprises:
a) providi.ng a granular material;
b) providing a binder material that is in a fluid state, c) cooling the binder material to a tempera-ture below its freezing point to form fine particles;
d) mixing the granular material and the cooled, particulate binder material -to form a homogeneous, easy flowing mixture; and e) compressing the resulting mixture to bind together th.e granular mate:rial to form a mould or core.
In this embodiment par-t or the entire necessary cooling may have been effected in advance, i.e. before the moulding process, so that the molten metal may be poured into the mould immediately after the termination of the moulding process. This provides for such a great production rate that the method may be used in connection with fast working automa-tic machines for the production of casting moulds with or without cores, e.g. of the type disclosed in the applicants' Danish Patent Specification No.
87,~62 to obtain the high operation rate of these machines.
When the binder has been frozen before the moulding process, it may be expedient that additionally at least one of the tools and/or materials which the binder is caused to contact in .~, i 3~Z~
the moulding process or in the mould and which may con-tain a binder previously used, has been cooled below the freezing poin-t of the binder or to a temperature slightly above said freeæing point.
The mould binder may have been cooled before -the mould manufacturing process so that it is presen-t in the form of fine, dendritic particles, e.g. snow, in the mould material, and a compression during the moulding process may entail that the binder obtains part of or its entire binding capacity depending upon the temperature conditions at the -time of the mould manufacturing process.
The mould binder used may also have been cooled before the mould manufacturing process so that it is present in the form of a finely divided powdered material, e.g. ice in the mould material, and a compression during the moulding process may entail that the binder obtains part of or its entire binding capacity depending upon the temperature conditions at the time of the mould manufacturing process.
When a suitable mixture of granular material and snow or broken ice is compressed in a mould box, the snow or the ice may thus be caused to bind the grains of the material toyether to impart a cohesive force to the mould or the core sufficient for it to resist the effect from liquid metal which is poured down into the finished mould with or without cores. A corresponding effect can be achieved by injecting one of the mentioned mixture of mould material into a core box with a sufficiently great force and at a sufficiently great rate.
The precooled binder in the form of pulverized material may also be combined with liquid gas. This permits -the temperature 33~) of the mould mater,ial to be reduced to a very low value before and during the moulding process and during the immediately following casting process. The mixture must be homophenols and easy flowing.
Actually, there is nothing -to prevent -the use of conventional setting binders. Thus, -to form a binder there may be used water glass and liquid carbon dioxide or a mixture of polyisocyanate and phenol resin which is activated by precooled, liquid dimethylethyl amine or triethyl amine. This provides Eor a reduction in the use of an environmentally harmful binder.
To obtain a better resistance to the heat effect of -the molten metal and thereby a delay in the hea-ting of -the mould or the core in the casting process, the granular material used for the formation of the mould or the core may have been deep-frozen in advance.
Additionally, the process ingredients may have been deep-frozen in advance by means of an admixed freezing agent, and the freezing agent used may expediently be liquid gas. The use of an inert gas, obviates any risk of chemical attacks on the equipment used for the process or for chemical reactions with the casting metal.
The required cooling may also be effected or be supported by deep-freezing the parts of the appara-tus which the mould material contacts during the moulding process. In the production of casting moulds, particularly the pattern board which contacts the same mould surface as the molten metal does later, may have been deep-frozen in advance and a core box deep-frozen in advance may be used in the production of cores. Also, the core box with the co~e or cores may be cooled simultaneously and 33,~
additionally e.cJ. with ]iquid cJas.
A specific embodiment of -the method of the invention in the production of casting moulds comprises the use of deep-Erozen disposable patterns of a material which evaporates when heated and this material may expediently have been deep-frozen ancl formed. Such patterns may be produced currently in a particular bifurcate pattern mould box corresponding -to a conventional core box and be placed in a closed chamber, following which the space between the pattern and the walls of the chamber is filled with the moulding material which is cooled by the pattern and may additionally have been cooled in advance as mentioned above. After the moulding proeess is finished the pattern evaporates rapidly owing to the heat received. This obviates the inconvenient development of gas, which otherwise takes place in the moulding of disposable patterns. This embodiment of the method results in particularly accurate eas-tings beeause the inaccuracies which in the conventional mould manufacturing process result from wear on the pattern board caused by shootings of sand, are avoided.
Moreover, bifurcation of the mould box is not required when readily evaporable patterns are used.
The invention also relates -to a plant for carrying out the disclosed method, which plant comprises an apparatus for the produetion of casting moulds or an apparatus for the production of eores, wherein the apparatus or at least one part thereof is contained in a cooling chamber. Aceording to the invention, the neeessary temperature eonditions may be readily and eonstantly maintained so that valuable produetion time is no-t lost in waiting for eooling.
33~Z() When the plan-t is connected to a casting plan-t having melting apparatus, a considerable saving in energy may be achieved by an arrangement such that waste heat from the melting apparatus is used for the operation of the cooling sys-tem of -the cooling chamber.
The inven-tion relates to a method oE producing frozen casting moulcls or cores of a granular material and a binder in a mould chamber or a core box, comprising the use of a Ereezable binder which is in a gas or liquid state a-t posi-tive temperatures calculated in degrees cen-tigrade.
The specification of the IJni-ted States Patent 4,150,70 -teaches a method in which the mould sand is admixed with a controlled quantity of water which after moulding is frozen to iee in a certain depth from the surface tha-t is caused to eontaet molten metal e.g. by placing a layer of so-called dry ice or spraying liquid nitrogen on the surface. This gives a very strong mould surface which retains its strength and shape until the surface of the metal has solidified. As the metal gives off its heat, the water melts and evaporates so that the mould begins collapsing without the use of mechanical means, practically no srnoke is developed in the casting process, and the mould sand can be reused right away.
An article in the Russian Magazine Liteinoe Proizvodsto, 1975, No. 5, P.21-22, describes the freezing of a sand mould containing 3 to 7 percent water by means of a coolan-t that circulates through the evaporator in a cooling system and through mould.
Freezing of the added water is by nature a rather slow process r and consequently it takes a relatively long time from the moment when the moulding process is finished until the mould has frozen deep enough to be able to resist the effect of molten metal for a sufficien-tly long time, and this in -turn causes the overall mould procduction to become considerably more time-consuming " v'l~
~833~
than the convellti.ona:L moulcl manufact-lring processes.
The object Or the inven-tion is to overcome -this drawback of the known embod.iments of -the presen-t methocl, and -this objec-t is achieved by the present inven-tion. Thus -the presen-t inventior provides a method of producing frozen casting moulds or cores, which method comprises:
a) providi.ng a granular material;
b) providing a binder material that is in a fluid state, c) cooling the binder material to a tempera-ture below its freezing point to form fine particles;
d) mixing the granular material and the cooled, particulate binder material -to form a homogeneous, easy flowing mixture; and e) compressing the resulting mixture to bind together th.e granular mate:rial to form a mould or core.
In this embodiment par-t or the entire necessary cooling may have been effected in advance, i.e. before the moulding process, so that the molten metal may be poured into the mould immediately after the termination of the moulding process. This provides for such a great production rate that the method may be used in connection with fast working automa-tic machines for the production of casting moulds with or without cores, e.g. of the type disclosed in the applicants' Danish Patent Specification No.
87,~62 to obtain the high operation rate of these machines.
When the binder has been frozen before the moulding process, it may be expedient that additionally at least one of the tools and/or materials which the binder is caused to contact in .~, i 3~Z~
the moulding process or in the mould and which may con-tain a binder previously used, has been cooled below the freezing poin-t of the binder or to a temperature slightly above said freeæing point.
The mould binder may have been cooled before -the mould manufacturing process so that it is presen-t in the form of fine, dendritic particles, e.g. snow, in the mould material, and a compression during the moulding process may entail that the binder obtains part of or its entire binding capacity depending upon the temperature conditions at the -time of the mould manufacturing process.
The mould binder used may also have been cooled before the mould manufacturing process so that it is present in the form of a finely divided powdered material, e.g. ice in the mould material, and a compression during the moulding process may entail that the binder obtains part of or its entire binding capacity depending upon the temperature conditions at the time of the mould manufacturing process.
When a suitable mixture of granular material and snow or broken ice is compressed in a mould box, the snow or the ice may thus be caused to bind the grains of the material toyether to impart a cohesive force to the mould or the core sufficient for it to resist the effect from liquid metal which is poured down into the finished mould with or without cores. A corresponding effect can be achieved by injecting one of the mentioned mixture of mould material into a core box with a sufficiently great force and at a sufficiently great rate.
The precooled binder in the form of pulverized material may also be combined with liquid gas. This permits -the temperature 33~) of the mould mater,ial to be reduced to a very low value before and during the moulding process and during the immediately following casting process. The mixture must be homophenols and easy flowing.
Actually, there is nothing -to prevent -the use of conventional setting binders. Thus, -to form a binder there may be used water glass and liquid carbon dioxide or a mixture of polyisocyanate and phenol resin which is activated by precooled, liquid dimethylethyl amine or triethyl amine. This provides Eor a reduction in the use of an environmentally harmful binder.
To obtain a better resistance to the heat effect of -the molten metal and thereby a delay in the hea-ting of -the mould or the core in the casting process, the granular material used for the formation of the mould or the core may have been deep-frozen in advance.
Additionally, the process ingredients may have been deep-frozen in advance by means of an admixed freezing agent, and the freezing agent used may expediently be liquid gas. The use of an inert gas, obviates any risk of chemical attacks on the equipment used for the process or for chemical reactions with the casting metal.
The required cooling may also be effected or be supported by deep-freezing the parts of the appara-tus which the mould material contacts during the moulding process. In the production of casting moulds, particularly the pattern board which contacts the same mould surface as the molten metal does later, may have been deep-frozen in advance and a core box deep-frozen in advance may be used in the production of cores. Also, the core box with the co~e or cores may be cooled simultaneously and 33,~
additionally e.cJ. with ]iquid cJas.
A specific embodiment of -the method of the invention in the production of casting moulds comprises the use of deep-Erozen disposable patterns of a material which evaporates when heated and this material may expediently have been deep-frozen ancl formed. Such patterns may be produced currently in a particular bifurcate pattern mould box corresponding -to a conventional core box and be placed in a closed chamber, following which the space between the pattern and the walls of the chamber is filled with the moulding material which is cooled by the pattern and may additionally have been cooled in advance as mentioned above. After the moulding proeess is finished the pattern evaporates rapidly owing to the heat received. This obviates the inconvenient development of gas, which otherwise takes place in the moulding of disposable patterns. This embodiment of the method results in particularly accurate eas-tings beeause the inaccuracies which in the conventional mould manufacturing process result from wear on the pattern board caused by shootings of sand, are avoided.
Moreover, bifurcation of the mould box is not required when readily evaporable patterns are used.
The invention also relates -to a plant for carrying out the disclosed method, which plant comprises an apparatus for the produetion of casting moulds or an apparatus for the production of eores, wherein the apparatus or at least one part thereof is contained in a cooling chamber. Aceording to the invention, the neeessary temperature eonditions may be readily and eonstantly maintained so that valuable produetion time is no-t lost in waiting for eooling.
33~Z() When the plan-t is connected to a casting plan-t having melting apparatus, a considerable saving in energy may be achieved by an arrangement such that waste heat from the melting apparatus is used for the operation of the cooling sys-tem of -the cooling chamber.
Claims (11)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of producing frozen casting moulds or cores, which method comprises:
a) providing a granular material;
b) providing a binder material that is in a fluid state;
c) cooling the binder material to a temperature below its freezing point to form fine particles;
d) mixing the granular material and the cooled, particulate binder material to form a homogeneous, easy flowing mixture; and e) compressing the resulting mixture to bind together the granular material to form a mould or core.
a) providing a granular material;
b) providing a binder material that is in a fluid state;
c) cooling the binder material to a temperature below its freezing point to form fine particles;
d) mixing the granular material and the cooled, particulate binder material to form a homogeneous, easy flowing mixture; and e) compressing the resulting mixture to bind together the granular material to form a mould or core.
2. A method according to claim 1, wherein the cooled binder material is in the form of fine dendritic particles.
3. A method according to claim 1, wherein the cooled binder material is in the form of finely divided powdered material.
4. A method according to claim 1, which comprises a further step of combining the cooled binder material with liquid gas prior to mixing with the granular material.
5. A method according to claim 1, wherein the binder material comprises water glass and liquid carbon dioxide.
6. A method according to claim 1, wherein the binder material comprises a mixture of polyisocyanate and phenol resin which is activated by pre-frozen liquid dimethylethyl amine or triethyl amine.
7. A method according to claim 1, which comprises a further step of providing deep-frozen disposable patterns of a material which evaporates when heated.
8. A method according to claim 7, wherein the disposable patterns are made from a deep-frozen, foamed material.
9. A method according to claim 1, 4 or 7, wherein the mould producing method is performed in a cooling chamber maintained at a reduced temperature.
10. A plant for carrying out the method according to claim 1, which comprises an apparatus for the production of casting moulds or an apparatus for the production of cores, wherein the apparatus or at least a part thereof is contained in a cooling chamber.
11. A plant according to claim 10, which is connected to a casting plant with melting apparatus and is arranged such that waste heat from the melting apparatus is used for the operation of the evaporator in the cooling system of the cooling chamber.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DK2675/80 | 1980-06-23 | ||
| DK267580A DK151776C (en) | 1980-06-23 | 1980-06-23 | PROCEDURE FOR THE PREPARATION OF FROZEN CASTLE OR CORE |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1183320A true CA1183320A (en) | 1985-03-05 |
Family
ID=8114515
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000380444A Expired CA1183320A (en) | 1980-06-23 | 1981-06-23 | Method of producing frozen casting moulds |
Country Status (13)
| Country | Link |
|---|---|
| EP (1) | EP0054061B1 (en) |
| JP (1) | JPH0144424B2 (en) |
| BE (1) | BE889350A (en) |
| CA (1) | CA1183320A (en) |
| CS (1) | CS257755B2 (en) |
| DD (1) | DD159531A5 (en) |
| DK (1) | DK151776C (en) |
| ES (1) | ES8301130A1 (en) |
| IT (1) | IT1136695B (en) |
| PL (1) | PL130506B1 (en) |
| SU (1) | SU1366043A3 (en) |
| WO (1) | WO1982000015A1 (en) |
| ZA (1) | ZA814230B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2681811A1 (en) * | 1991-09-27 | 1993-04-02 | Air Liquide | PROCESS FOR MANUFACTURING WORKPIECES. |
| CN113579161B (en) * | 2021-07-28 | 2022-11-01 | 南京航空航天大学 | Large complex freezing sand mold low-temperature forming and over-cold-control cooperative manufacturing method |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU428843A1 (en) * | 1971-01-04 | 1974-05-25 | METHOD FOR MAKING CASTING FORMS BY FREEZING | |
| US3978906A (en) * | 1974-01-29 | 1976-09-07 | Borden, Inc. | Process for the rapid production of foundry molds and cores and to a composition for use therein |
| NO142944L (en) * | 1975-08-14 | 1900-01-01 | ||
| JPS592575B2 (en) * | 1978-06-17 | 1984-01-19 | 淳策 中島 | Freezing mold manufacturing method and its equipment |
| SU718215A1 (en) * | 1978-09-21 | 1980-02-29 | Предприятие П/Я А-3470 | Method of manufacturing frozen molds |
| JPS5548452A (en) * | 1978-09-29 | 1980-04-07 | Ishikawa Chuzosho:Kk | Manufacture of mold |
| PL124538B1 (en) * | 1979-02-16 | 1983-01-31 | Inst Odlewnictwa | Method of making foundry moulds and cores |
| DE2909839A1 (en) * | 1979-03-13 | 1980-09-25 | Linde Ag | Foundry moulds made by freezing moist sand - where sand cooled by liq. nitrogen is mixed with damp sand and driven into moulding box (OE 15.3.80) |
| DE2912201A1 (en) * | 1979-03-28 | 1980-10-09 | Linde Ag | Foundry moulds made by freezing moist sand - where sand is cooled by liq. nitrogen or carbon di:oxide, and then sprayed onto pattern together with cold water |
| PL124680B1 (en) * | 1979-09-27 | 1983-02-28 | Inst Odlewnictwa | Apparatus for making casting moulds and cores |
| PL124681B1 (en) * | 1980-05-12 | 1983-02-28 | Odlewniczych Fab Mas | Method of and apparatus for making casting moulds |
-
1980
- 1980-06-23 DK DK267580A patent/DK151776C/en active
-
1981
- 1981-06-19 IT IT22460/81A patent/IT1136695B/en active
- 1981-06-22 JP JP56502323A patent/JPH0144424B2/ja not_active Expired
- 1981-06-22 EP EP81901923A patent/EP0054061B1/en not_active Expired
- 1981-06-22 ES ES503284A patent/ES8301130A1/en not_active Expired
- 1981-06-22 CS CS814707A patent/CS257755B2/en unknown
- 1981-06-22 WO PCT/DK1981/000062 patent/WO1982000015A1/en active IP Right Grant
- 1981-06-23 DD DD81231059A patent/DD159531A5/en not_active IP Right Cessation
- 1981-06-23 CA CA000380444A patent/CA1183320A/en not_active Expired
- 1981-06-23 ZA ZA814230A patent/ZA814230B/en unknown
- 1981-06-23 BE BE0/205189A patent/BE889350A/en not_active IP Right Cessation
- 1981-09-23 PL PL1981231819A patent/PL130506B1/en unknown
-
1982
- 1982-02-22 SU SU823398237A patent/SU1366043A3/en active
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57500819A (en) | 1982-05-13 |
| EP0054061A1 (en) | 1982-06-23 |
| EP0054061B1 (en) | 1984-10-03 |
| ZA814230B (en) | 1982-04-28 |
| DD159531A5 (en) | 1983-03-16 |
| PL231819A1 (en) | 1982-02-15 |
| SU1366043A3 (en) | 1988-01-07 |
| DK151776B (en) | 1988-01-04 |
| BE889350A (en) | 1981-12-23 |
| DK267580A (en) | 1981-12-24 |
| DK151776C (en) | 1988-08-15 |
| JPH0144424B2 (en) | 1989-09-27 |
| CS257755B2 (en) | 1988-06-15 |
| IT8122460A0 (en) | 1981-06-19 |
| PL130506B1 (en) | 1984-08-31 |
| IT1136695B (en) | 1986-09-03 |
| WO1982000015A1 (en) | 1982-01-07 |
| ES503284A0 (en) | 1982-11-16 |
| ES8301130A1 (en) | 1982-11-16 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |