CA1039925A - Sandwich structure monolithic mold - Google Patents
Sandwich structure monolithic moldInfo
- Publication number
- CA1039925A CA1039925A CA215,015A CA215015A CA1039925A CA 1039925 A CA1039925 A CA 1039925A CA 215015 A CA215015 A CA 215015A CA 1039925 A CA1039925 A CA 1039925A
- Authority
- CA
- Canada
- Prior art keywords
- mold
- binder
- layer
- pattern
- organic
- 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
- B22C9/02—Sand moulds or like moulds for shaped castings
- B22C9/04—Use of lost patterns
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
- B22C1/16—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents
- B22C1/165—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents in the manufacture of multilayered shell moulds
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Molds, Cores, And Manufacturing Methods Thereof (AREA)
- Mold Materials And Core Materials (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A monolithic mold and fabricatior method is disclosed for use in molding precision cast parts. In cross-section the mold has inner and outer layers, the essential ingredients of which include a ceramic refractory material and an inorganic binder. Intermediate layers are disposed between the inner and outer layers and employ an organic fugitive binder. When the mold is heated prior to receiving molten metal, the fugi-tive binder is volatilized, leaving the intermediate layer un-bound. After the parts have been cast the mold is easily col-lapsed for removal of the casting without damage.
A monolithic mold and fabricatior method is disclosed for use in molding precision cast parts. In cross-section the mold has inner and outer layers, the essential ingredients of which include a ceramic refractory material and an inorganic binder. Intermediate layers are disposed between the inner and outer layers and employ an organic fugitive binder. When the mold is heated prior to receiving molten metal, the fugi-tive binder is volatilized, leaving the intermediate layer un-bound. After the parts have been cast the mold is easily col-lapsed for removal of the casting without damage.
Description
10399~5 ^`: `
S P E C I F I C A T I 0 ~
This invention relates to the art of precision cast-ing and to materials employed in the practice thereo~. More particularly, the invention relates to a casting process and to compositions and methods used in the preparation of molds. ~;
A basic process employed in casting precision parts is known as the lost wax process. mis process is particular-ly adapted to producing precision castings for the production of turbine blades, vanes, as well as other complex parts. me conventional lost wax process consists o~ producing disposable ~;
patterns form~d of wax, plastic or other suitable material hav- ; :
ing the desired shape. If necessary, these patterns are assem- ``
bled into clusters to form a complete assembly. The patterns are then dipped into a ceramic slurry dipcoat containing a col-loidal silica or other inorganic binder. While the pattern is wet from the dipcoat, it is stuccoed with granular refractory ~;
.:. .: , particles and then dried. This forms a coating on the patterns ~
and by repeating the dipping, stuccoing and drying steps~ a mold ;
o a desired thickness can be formed about the pattern.
The pattern is then removed from the mold and the -20 mold is heated to a temperature whereby the silica binder cures '~
and strongly bonds the ceramic dipcoating and granular stucco into a monolithic mass. A~ter inspection, the mold is preheated ~;
to a high temperature suitable for receiving molten metal.
After pouring the metal, the casting is allowed to cool to a solidified state. At this stage~ the mold strength can be higher than the metal strength, often resulting in "hot tears" on the casting. After cooling, the mold is broken away from the casting by mechanical or pneumatic vibration, salt bathing, sand blasting or other techniques.
3 The above described techniques for separation of the ~1, '.. ~
1039g25 casting from the mold have several disadvantages. The high amplitude mechani-cal vibration necessary to break the mold can cause cracking of the casting.
Salt bathing techniques and sand blasting are excessively time consuming and `~
also detrimental to the casting surface in that intergranular attack and surface erosion occurs. -It is accordingly an object of the present invention to produce and provide a method for producing new and improved molds for use in precision casting.
More specifically, it is an object of the present invention to produce a mold which is of sufficiently high strength and stability to enable casting materials to be poured directly therein for molding, and yet which can be easily broken away rom the casting without damage thereto.
It is another object of the present invention to provide a mold in which at least some of the materials used therein can be reclaimed and re-used.
It is still a urther object of the present inventlon to provide a sandwich structured mold which eliminates casting "hot tears" and knockout cracks.
According to one aspect of the invention, there is provided a method of producing a recyclable sandwich structure monolithic mold about a dispos-able pattern which is removed to define a mold cavity comprising the steps of: `
(a) wetting the surface of the pattern with a first dipcoat com-position, the essential solids o which consist of finely divided refractory , . ' r~ .
material, including an inorganic binder; ;
~ b) covering the surface of the pattern, while wet with the firstdipcoat, with a granular refractory stucco;
~ c) repeating, at least once, steps (a) and ~b) with intervening drying to form a first layer of said mold; i ~ d) wetting said first layer with a second dipcoat composition, the essential ingredients including finely divided reractory material and an or-ganic fugitive binder;
~e) covering the surface of the first layer while wet with the .. ~.
~ -2-.
second dipcoat with a granular refractory stucco;
~f) repeating, at least once, steps (d) and (e) with intervening ~ ~ -drying to form an intermediate layer of said mold; and (g) forming an outer layer over said intermediate layer in the -`
manner recited in steps (a), (b) and (c), to thereby produce a three layer ~;-sandwich structure mold.
Another aspect of the invention provides a sandwich structure recyclable monolithic mold for precision casting having a wall structure in ~ -cross-section comprising: ~-(a) an inner layer consisting essentially of finely divided re-fractory material, including an inorganic binder and granular refractory stucco;
tb) an intermediate layer consisting essentially of finely divided refractory material, refractory stucco and an organic fugitive binder;
(c) an outer layer identical in composition in said inner layer.
A further aspect of the invention provides a method of precision casting materials, such as metal alloys, comprising the steps of:
ta) producing a sandwich structure monolithic mold about a dis-posable pattern, said mold having inner and outer layers consisting essentially of finely divided refractory material, including an inorganic binder and gran- ;
ular refractory stucco J and an intermediate layer consistin~ essentially of finely divided refractory material, refractory stucco, and an organic fugitive binder;
~b) removing said disposable pattern from said mold to provide a mold cavity;
(c) firing said mold to a temperature sufficient to volatilize ~ ~
said organic fugitive binder to thereby leave said intermediate layer unbound `- `
and sandwiched between the bound inner and outer layers; ~
(d) pouring a molten metal alloy into said mold cavity; ~;
~e) cooling the mold;
~f) removing the mold from the cast metal alloy. -Thus, a mold for casting precision parts is formed by dipping a ;
wax or plastic pattern into a dipcoat of a first composition including finely ,. : - .
-2a-10399;25 ~
divided refractory materials and an inorganic binder, such as a silica binder.
While the pattern is still wet, it is stuccoed with granular refractory parti-cles, and then dried. This sequence is repeated as desired to build up an inner layer of a desired thickness. The pattern and inner -a~ -.. ..... ... .. . . . . ~ . ..
.
~0399Z5 layer are then dipped into a second dipcoat, the principal constituents of which are finely divided refractory material and an organic fugitive binder. After stuccoing, this coating is dried. This intermediate layer may be built up as desired by repeating the sequence.
Finally, an outer layer is formed over the intermedi~
ate layer and is composed somewhat of the same inorganic con-stituents as the inner layer, thereby forming a mold which is sandwich structured. When the mold is preheated prior to metal pouring (after the pattern has been removed), the organic fugi-tive binder of the intermediate layer is substantially elimina-ted by burning and/or volatilization. This leaves the materials of the intermediate layer without binder sandwiched between the inner and outer layers.
After molding, the sandwich mold is easily removed ~rom the casting by collapsing the outer layer onto the inter-mediate layer and removing the thin inner layer. This mold avoids "hot tears" as well as cracking in the casting due to the force heretofore required for mold removal. - ~`
Brief Description of the Drawinqs ~`
Fig. 1 is a schematic sectional view through a pat- ~
tern having a mold formed thereon in accordance with the prac- `
tice o~ this invention; and Fig. 2 is a flow diagram of the process embodying the practice of this invention.
Detailed Description The concepts of this invention are embodied in two phases, a "mold phase" which includes the compositions employed -~
in the manufacture of the mold and the method for the produc-tion thereof, and the "use phase" wherein the ~ormed mold is employed in the process of molding compositions and materials.
,"
-3- ;
1~3~25 `-me mold phase will be described with reference to compositions employed and the methods of manufacture in a rep-resentative process illustrating the practice of this phase :
of the invention.
In the following description, the term "pattern" will be used interchangeably with "cluster" to refer to a wax or plastic pattern 10 or a cluster formed of a multiplicity of such individual patterns.
The pattern 10 is formed of conventional materials disposable by heat or chemicals. If the mold is to be formed about more than one pattern~ the plurality of patterns are con- ~ "
nected by runners for communication with a pouring spout to form a completed cluster. Where the cluster is to be repeated- -ly dipped into slurry, identified as a dipcoat, it is desirable to provide a hanger rod for carrying the cluster and for sus- -pending the cluster for drying and t'he like.
First Dipcoatinq Composition ;
8000 cc. colloidal silica (30% grade) (specific gravity 1.198) 165 pounds zircon (99% through 325 mesh) 6150 cc. water 110 grams sodium fluoride Application of First Dipcoat Composition me pattern or cluster is first inspected to remove dirt, flakes and other objects which may have adhered to the surfaces of the pattern and which, if allowed to remain, would impair the preparation of a good mold and lead to an unaccepta- -ble casting. The cleaned cluster is immersed into the stirred dipcoat composition to cover all of the surfaces of the cluster.
3 To promote the elimination of air pockets, it is desirable to :`
`:
lQ399ZS ~`
rotate the cluster while immersing in the dipcoat composition. -~ -Alternately, the dipcoat composition can be applied by spraying -the dipcoat composition onto the surfaces of the pattern. -~ hen fully wet, the pattern or cluster is suspended to drain excess dipcoat composition. During drainage, the clus-ter can be inspected to detect air pockets which can be elimin-ated by àddressing a stream of air onto the uncoated portions and thereafter allowing the slurry of the dipcoat composition to flow onto the uncovered areaO While the cluster is being -~
drained, it should be held in different spatial planes design-ed to achieve uniform coating on all surfaces. In general, drainage should be completed within a few minutes but, in any event, in less time than would allow the dipcoat composition to dry whereby the surface would not retain stucco, as will be , .. . .
described.
First Stucco Coat Stucco combination--Alundum* ~100% through 50 mesh with less than 3% through 100 mesh--better than 90% between 60 and 80 mesh). `~
Application of Stucco Coat After the uniformity of coating has been achieved in the first dipcoat and dripping from the patterns has become mini-~ . - -: .
mized, the stucco is sprinkled onto the wet cluster substantial-ly uniformly to cover thè wet surfaces with a layer of the stucco ~ -while, at the same time, minimizing flow of the dipcoat whereby non-uni~ormities might otherwise develop. In practice, the stucco particles will be rained down from above through a screening member constantly being fed by a vibratory feeder to ~ ~ ;
remove foreign matter from the alundum particles~ while the particles are sprinkled over an area to give more uniform and `
,. :,:' ~
*trademark for fused alumina refractory and abrasive products ~ ~
- 5 - :
lQ39925 complete coverage. m e stucco will adhere to the wet coating of the slurry and will become partially embedded in the slurry to become integrated with the coating formed on the cluster of wax patterns.
By repeating the above steps, after intermediate dry-ing, the first dipcoat composition and stucco are built up onto the pattern to form an inner layer 12 of a desired thickness. ; -For the purposes of casting molten metal products of normal weight, it is desirable to pro~ide for more than one dipcoat-stuccoing cycle. After sufficient drying, the pattern is then emersed into a second dipcoat to ~orm an intermediate layer 14.
Second Dipcoatinq Composition Example A.
-325 Mesh Alumina Flour --~ ------------ 3500 Gr Polyvinyl Alcohol (7.26% Aqu~ous Solution) __ 1033 Gr Potato Starch (3% Water 5O1ution) -----------938 Gr Anionic Wetting Agent ----------------------- 42 cc Example B.
-325 Mesh Alumina Flour --------------------- 3500 Gr Polyvinyl Alcohol (7.26% Aqueous Solution) -- 2000 Gr Anionic Wetting Agent ----------------------- 42 cc Example C. --400 Mesh Zircon Flour ---------------------- 4040 Gr Polyvinyl Alcohol (7.26% Aqueous Solution) -- 1033 Gr Potato Starch (3% Water Solution) -----------938 Gr Anionic Wetting Agent ----------------------- 42 cc Anti-foam Colloid --------------------------- 21 cc - Example D.
-400 Mesh Zircon Flour ---------------~ -- 4040 Gr 3 Polyvinyl Alcohol (7.26% A~ueous Solution) -- 1975 Gr '' ' ' 1~399~5 ;
Anionic Wetting Agent ~ --------------- 42 cc Anti-foam Colloid -------------------------- 21 cc ;:
Example E.
-325 Mesh Alumina Flour --------------------- 122.7 Lbs 5(Aquadag) Colloidal Graphite (22% Solids) --- 10.7 Lbs .
Water (Distilled) --------------------------- 26.3 Lbs -Anionic Wetting Agent --~ ----------------- 418.0 cc Gum Tragacanth Solution --------------------- 456.0 cc - -Example F.
~R 10-325 Zircon Flour --------------------------- 33.0 ~bs (Aquadag) Colloidal Graphite (22% Solids in ', Water) -------------------------------- 8.8 hbs :~
Water (Distilled) --------------------------- 11.0 Lbs Anionic Wetting Agent ----------------------- 200.0 cc i 15Gum Tragacanth Solution --------------------- 300.0 cc Example G. .
-325 Mesh Zircon Flour ---------------------- 160.0 1bs -hatex --------------------------------------- 280.0 cc Wa~er --------------------------------------- 14000 cc 20Gum Tragacanth Solution --------------------- 300Øcc Anionic Wetting Agent ----------------------- 400.0 cc ~
Octyl AlcohoI ------------------------------- 49.0 cc :
In examples E, F, and G the gum tragacanth solution ', , has tha following composition:
Gum Tragacanth Powder ----------------------- L~445 Gr Sodium Benzoate ----------------------------- 5 Gr .
Water --------------------------------------- 20,000 Gr ,. -:~ - .. . ~ . .
As the anionic wetting agent, use can be made of sodium `~
heptadecyl sulphate, such as Tergitol Anionic No. 7 of Union Carbide Corporation.
','' '. '~ ' ~ -t~ ~Je~ a r.~ _7_ ,', .! . ` i ; 1~ . . ' Representative of the antifoam colloids which may be -`-used in the above formulations is Antifoam Colloid No. 581B
produced by Colloids, Inc., ~ewark, ~ew Jersey.
Application of Second Dipcoat Composition The second dipcoat composition is applied to the coat-ed pattern in a manner similar to that of the first dipcoat com-position. A significant difference between the dipcoat compo-sitions is in the selection of the binder. The first dipcoat composition employs a colloidal silica binder. The second dip- -coat composition preferably utilizes an organic fugitive binder as, or examp:Le, polyvinyl alcohol. By organic fugitive binder it is possible to form a second intermediate layer about the pattern, and at a subsequent time drive off the binder to leave the intermediate layer closely packed but unbound.
In the preferred practice of this invention~ it is de-sired, although not essential, to precede the emersion of the coated pattern into the first and second dipcoat compositions with a pre-wetting step in which the pre-wetting composition employs substantially the same formulation as the dipcoat com-position, with the exception that a lower viscosity is employed.
me pre-wetting composition includes additional amounts of water sufficient to reduce the total solids to about 25% to 75% of the total solids in the dipcoat composition. Thus, the coated pattern, having the inner layer 12 dried thereon, is submerged into a pre-wetting composition more completely to penetrate and wet out the coated surface prior to being immersed in the second dipcoat composition. Immersion into the second dipcoat compo-sition follows immediately after the pre-wet immersion.
After the immersion in the second dipcoat composition, 3 the pattern is again allowed to drain and is stuccoed and dried.
.- . , .. ;:. . . : ~ :
:IV39925 "`
The steps of pre-wetting, dipcoating, stuccoing and drying are repeated one or more times, as necessary, to build up the inter-mediate layer 14 to a desired thickness. me stucco employed for the intermediate layer may be the same as that employed for the inner layer.
For special applications and particularly where large molds are utilized, it is desirable to add a very small percent-age, on the order of 0.125% by weight, of colloidal silica binder to the second dipcoat composition which also contains the organic fugitive binder as previously discussed. m e pres-ence of the colloidal silica binder prevents the intermediate layer from becoming completely powdery after the fugitive bind-er is driven off as will be described. The small amount of silica binder added to the second dipcoat does not increase the strength or increase the task oE removal buk permits patching and repair of the mold should such operations be necessary. The following example illustrates the use of a small amount of sili-ca binder in the second dipcoat:
Example H. ;
Zircon Flour ----------------------------------- 154 Lbs Antifoam Colloid ------------------------------- 500 cc Anionic Wetting Agent -------------------------- 720 cc Colloidal Silica (30% Sol.) -------------------- 242 cc .: .' . .. .
Polyvinyl Alcohol (7.26% Sol.) ----------------- 30.0 Lbs Water ------------------------------------------ 18.7 Lbs ;-Third Dipcoat Composition and Application `
~ . . . .
The composition of the third dipcoat, which forms the outer layer 16 of the mold can, but need not be, the same ~;
as the composition of the first dipcoat. It is applied and r ; `
3 stuccoed in a manner similar to that of the first dipcoat.
. . .
'-:
_g_ ' ~0399~5 However, usually a coarser stucco is applied. When the outer layer 16 has been built up to a desired thickness the mold is subjected to a final arying cycle.
As an example of the number of dipcoats required to form each of the three layers of the sandwich structure for an average weight casting, two dipcoatings have been employed to form the inner layer 12, three dipcoatings have been employed to form the intermediate layer 14, followed by two dipcoats in the first dipcoat composition to form the outer layer 16. For heavier castings or for large molds, the thickness of the lay-ers may be increased as necessary.
After final drying, the completed mold is heated toremove the pattern contained therein, and laave a mold cavity in which the material to be cast is poured. Pattern removal, hereinafter referred to as dewaxing, can be achieved in a num-ber of ways. Usually dewaxing the mold is accomplished by firing it to a high temperature. During such heating, the col-loidal silica binder in the inner and outer layers 12 and 16 strongly bonds the ceramic dipcoat and granular stucco into a monolithic mass. Simultaneously, the organic fugitive binder in the intermediate layer 14 is volatilized and/or burned out leaving the materials making up the intermediate layer unbond-ed and sandwiched between the inner and outer bonded layers.
Alternately, the sandwich structure mold of the pres-ent invention can be dewaxed at a lower temperature on theorder of 200 to 400 F. This dewaxing method is possible due to the high green strength achieved in the present sandwich structure mold.
If the sandwich mold is dewaxed at a low temperature, then it will be preheated to a high temperature prior to use~
,. . .
-10- '-~039925 ` `
as indicated in Fig. 2, for burning out the mold, i.e., remov- -ing any small traces of remaining wax, for burning out or vola- -~' ' ' !, . . .
tilizing the organic binder used for the intermediate layer and for curing the silica binder. Preheating is usually car- --ried out at temperatures in the range of 1000 to 2850 F.
me sandwich structure mold, after being preheated, is ready for pouring the molten metal in the mold cavity. Dur-ing the preheating and pouring of the metal, the sandwich struc-ture mold does not gain sufficient additional strength to cause excessive hardening of the mold. Another advantage of a sand-wich structure mold is that, during the cooling process, the `
relatively thin inner layer 12 is able to collapse, thereby ^ `~
eliminating the possibility of casting hot tears.
After the casting has cooled completely, the mold is ~`
removed. Its construction permits the use of low amplitude me-chanical vibration to crack the thin outer layer 16, which breaks off easily. The intermediate layer, being unbound, falls away from the mold and, if desired, may be reclaimed for re-use.
me portions of the inner layer are similarly easily broken away.
The castings resulting from this process are rela-tively free of mold materials, hot tears, and knock-out cracks. -Also, sand blasting for final cleaning is minimized.
While I have shown and described an embodiment of this invention in some detail, it will be understood that this de- `
scription and illustration are offered merely by way of example, and that the invention is to be limited in scope only by the appended claims.
'',., '`
-11- .
S P E C I F I C A T I 0 ~
This invention relates to the art of precision cast-ing and to materials employed in the practice thereo~. More particularly, the invention relates to a casting process and to compositions and methods used in the preparation of molds. ~;
A basic process employed in casting precision parts is known as the lost wax process. mis process is particular-ly adapted to producing precision castings for the production of turbine blades, vanes, as well as other complex parts. me conventional lost wax process consists o~ producing disposable ~;
patterns form~d of wax, plastic or other suitable material hav- ; :
ing the desired shape. If necessary, these patterns are assem- ``
bled into clusters to form a complete assembly. The patterns are then dipped into a ceramic slurry dipcoat containing a col-loidal silica or other inorganic binder. While the pattern is wet from the dipcoat, it is stuccoed with granular refractory ~;
.:. .: , particles and then dried. This forms a coating on the patterns ~
and by repeating the dipping, stuccoing and drying steps~ a mold ;
o a desired thickness can be formed about the pattern.
The pattern is then removed from the mold and the -20 mold is heated to a temperature whereby the silica binder cures '~
and strongly bonds the ceramic dipcoating and granular stucco into a monolithic mass. A~ter inspection, the mold is preheated ~;
to a high temperature suitable for receiving molten metal.
After pouring the metal, the casting is allowed to cool to a solidified state. At this stage~ the mold strength can be higher than the metal strength, often resulting in "hot tears" on the casting. After cooling, the mold is broken away from the casting by mechanical or pneumatic vibration, salt bathing, sand blasting or other techniques.
3 The above described techniques for separation of the ~1, '.. ~
1039g25 casting from the mold have several disadvantages. The high amplitude mechani-cal vibration necessary to break the mold can cause cracking of the casting.
Salt bathing techniques and sand blasting are excessively time consuming and `~
also detrimental to the casting surface in that intergranular attack and surface erosion occurs. -It is accordingly an object of the present invention to produce and provide a method for producing new and improved molds for use in precision casting.
More specifically, it is an object of the present invention to produce a mold which is of sufficiently high strength and stability to enable casting materials to be poured directly therein for molding, and yet which can be easily broken away rom the casting without damage thereto.
It is another object of the present invention to provide a mold in which at least some of the materials used therein can be reclaimed and re-used.
It is still a urther object of the present inventlon to provide a sandwich structured mold which eliminates casting "hot tears" and knockout cracks.
According to one aspect of the invention, there is provided a method of producing a recyclable sandwich structure monolithic mold about a dispos-able pattern which is removed to define a mold cavity comprising the steps of: `
(a) wetting the surface of the pattern with a first dipcoat com-position, the essential solids o which consist of finely divided refractory , . ' r~ .
material, including an inorganic binder; ;
~ b) covering the surface of the pattern, while wet with the firstdipcoat, with a granular refractory stucco;
~ c) repeating, at least once, steps (a) and ~b) with intervening drying to form a first layer of said mold; i ~ d) wetting said first layer with a second dipcoat composition, the essential ingredients including finely divided reractory material and an or-ganic fugitive binder;
~e) covering the surface of the first layer while wet with the .. ~.
~ -2-.
second dipcoat with a granular refractory stucco;
~f) repeating, at least once, steps (d) and (e) with intervening ~ ~ -drying to form an intermediate layer of said mold; and (g) forming an outer layer over said intermediate layer in the -`
manner recited in steps (a), (b) and (c), to thereby produce a three layer ~;-sandwich structure mold.
Another aspect of the invention provides a sandwich structure recyclable monolithic mold for precision casting having a wall structure in ~ -cross-section comprising: ~-(a) an inner layer consisting essentially of finely divided re-fractory material, including an inorganic binder and granular refractory stucco;
tb) an intermediate layer consisting essentially of finely divided refractory material, refractory stucco and an organic fugitive binder;
(c) an outer layer identical in composition in said inner layer.
A further aspect of the invention provides a method of precision casting materials, such as metal alloys, comprising the steps of:
ta) producing a sandwich structure monolithic mold about a dis-posable pattern, said mold having inner and outer layers consisting essentially of finely divided refractory material, including an inorganic binder and gran- ;
ular refractory stucco J and an intermediate layer consistin~ essentially of finely divided refractory material, refractory stucco, and an organic fugitive binder;
~b) removing said disposable pattern from said mold to provide a mold cavity;
(c) firing said mold to a temperature sufficient to volatilize ~ ~
said organic fugitive binder to thereby leave said intermediate layer unbound `- `
and sandwiched between the bound inner and outer layers; ~
(d) pouring a molten metal alloy into said mold cavity; ~;
~e) cooling the mold;
~f) removing the mold from the cast metal alloy. -Thus, a mold for casting precision parts is formed by dipping a ;
wax or plastic pattern into a dipcoat of a first composition including finely ,. : - .
-2a-10399;25 ~
divided refractory materials and an inorganic binder, such as a silica binder.
While the pattern is still wet, it is stuccoed with granular refractory parti-cles, and then dried. This sequence is repeated as desired to build up an inner layer of a desired thickness. The pattern and inner -a~ -.. ..... ... .. . . . . ~ . ..
.
~0399Z5 layer are then dipped into a second dipcoat, the principal constituents of which are finely divided refractory material and an organic fugitive binder. After stuccoing, this coating is dried. This intermediate layer may be built up as desired by repeating the sequence.
Finally, an outer layer is formed over the intermedi~
ate layer and is composed somewhat of the same inorganic con-stituents as the inner layer, thereby forming a mold which is sandwich structured. When the mold is preheated prior to metal pouring (after the pattern has been removed), the organic fugi-tive binder of the intermediate layer is substantially elimina-ted by burning and/or volatilization. This leaves the materials of the intermediate layer without binder sandwiched between the inner and outer layers.
After molding, the sandwich mold is easily removed ~rom the casting by collapsing the outer layer onto the inter-mediate layer and removing the thin inner layer. This mold avoids "hot tears" as well as cracking in the casting due to the force heretofore required for mold removal. - ~`
Brief Description of the Drawinqs ~`
Fig. 1 is a schematic sectional view through a pat- ~
tern having a mold formed thereon in accordance with the prac- `
tice o~ this invention; and Fig. 2 is a flow diagram of the process embodying the practice of this invention.
Detailed Description The concepts of this invention are embodied in two phases, a "mold phase" which includes the compositions employed -~
in the manufacture of the mold and the method for the produc-tion thereof, and the "use phase" wherein the ~ormed mold is employed in the process of molding compositions and materials.
,"
-3- ;
1~3~25 `-me mold phase will be described with reference to compositions employed and the methods of manufacture in a rep-resentative process illustrating the practice of this phase :
of the invention.
In the following description, the term "pattern" will be used interchangeably with "cluster" to refer to a wax or plastic pattern 10 or a cluster formed of a multiplicity of such individual patterns.
The pattern 10 is formed of conventional materials disposable by heat or chemicals. If the mold is to be formed about more than one pattern~ the plurality of patterns are con- ~ "
nected by runners for communication with a pouring spout to form a completed cluster. Where the cluster is to be repeated- -ly dipped into slurry, identified as a dipcoat, it is desirable to provide a hanger rod for carrying the cluster and for sus- -pending the cluster for drying and t'he like.
First Dipcoatinq Composition ;
8000 cc. colloidal silica (30% grade) (specific gravity 1.198) 165 pounds zircon (99% through 325 mesh) 6150 cc. water 110 grams sodium fluoride Application of First Dipcoat Composition me pattern or cluster is first inspected to remove dirt, flakes and other objects which may have adhered to the surfaces of the pattern and which, if allowed to remain, would impair the preparation of a good mold and lead to an unaccepta- -ble casting. The cleaned cluster is immersed into the stirred dipcoat composition to cover all of the surfaces of the cluster.
3 To promote the elimination of air pockets, it is desirable to :`
`:
lQ399ZS ~`
rotate the cluster while immersing in the dipcoat composition. -~ -Alternately, the dipcoat composition can be applied by spraying -the dipcoat composition onto the surfaces of the pattern. -~ hen fully wet, the pattern or cluster is suspended to drain excess dipcoat composition. During drainage, the clus-ter can be inspected to detect air pockets which can be elimin-ated by àddressing a stream of air onto the uncoated portions and thereafter allowing the slurry of the dipcoat composition to flow onto the uncovered areaO While the cluster is being -~
drained, it should be held in different spatial planes design-ed to achieve uniform coating on all surfaces. In general, drainage should be completed within a few minutes but, in any event, in less time than would allow the dipcoat composition to dry whereby the surface would not retain stucco, as will be , .. . .
described.
First Stucco Coat Stucco combination--Alundum* ~100% through 50 mesh with less than 3% through 100 mesh--better than 90% between 60 and 80 mesh). `~
Application of Stucco Coat After the uniformity of coating has been achieved in the first dipcoat and dripping from the patterns has become mini-~ . - -: .
mized, the stucco is sprinkled onto the wet cluster substantial-ly uniformly to cover thè wet surfaces with a layer of the stucco ~ -while, at the same time, minimizing flow of the dipcoat whereby non-uni~ormities might otherwise develop. In practice, the stucco particles will be rained down from above through a screening member constantly being fed by a vibratory feeder to ~ ~ ;
remove foreign matter from the alundum particles~ while the particles are sprinkled over an area to give more uniform and `
,. :,:' ~
*trademark for fused alumina refractory and abrasive products ~ ~
- 5 - :
lQ39925 complete coverage. m e stucco will adhere to the wet coating of the slurry and will become partially embedded in the slurry to become integrated with the coating formed on the cluster of wax patterns.
By repeating the above steps, after intermediate dry-ing, the first dipcoat composition and stucco are built up onto the pattern to form an inner layer 12 of a desired thickness. ; -For the purposes of casting molten metal products of normal weight, it is desirable to pro~ide for more than one dipcoat-stuccoing cycle. After sufficient drying, the pattern is then emersed into a second dipcoat to ~orm an intermediate layer 14.
Second Dipcoatinq Composition Example A.
-325 Mesh Alumina Flour --~ ------------ 3500 Gr Polyvinyl Alcohol (7.26% Aqu~ous Solution) __ 1033 Gr Potato Starch (3% Water 5O1ution) -----------938 Gr Anionic Wetting Agent ----------------------- 42 cc Example B.
-325 Mesh Alumina Flour --------------------- 3500 Gr Polyvinyl Alcohol (7.26% Aqueous Solution) -- 2000 Gr Anionic Wetting Agent ----------------------- 42 cc Example C. --400 Mesh Zircon Flour ---------------------- 4040 Gr Polyvinyl Alcohol (7.26% Aqueous Solution) -- 1033 Gr Potato Starch (3% Water Solution) -----------938 Gr Anionic Wetting Agent ----------------------- 42 cc Anti-foam Colloid --------------------------- 21 cc - Example D.
-400 Mesh Zircon Flour ---------------~ -- 4040 Gr 3 Polyvinyl Alcohol (7.26% A~ueous Solution) -- 1975 Gr '' ' ' 1~399~5 ;
Anionic Wetting Agent ~ --------------- 42 cc Anti-foam Colloid -------------------------- 21 cc ;:
Example E.
-325 Mesh Alumina Flour --------------------- 122.7 Lbs 5(Aquadag) Colloidal Graphite (22% Solids) --- 10.7 Lbs .
Water (Distilled) --------------------------- 26.3 Lbs -Anionic Wetting Agent --~ ----------------- 418.0 cc Gum Tragacanth Solution --------------------- 456.0 cc - -Example F.
~R 10-325 Zircon Flour --------------------------- 33.0 ~bs (Aquadag) Colloidal Graphite (22% Solids in ', Water) -------------------------------- 8.8 hbs :~
Water (Distilled) --------------------------- 11.0 Lbs Anionic Wetting Agent ----------------------- 200.0 cc i 15Gum Tragacanth Solution --------------------- 300.0 cc Example G. .
-325 Mesh Zircon Flour ---------------------- 160.0 1bs -hatex --------------------------------------- 280.0 cc Wa~er --------------------------------------- 14000 cc 20Gum Tragacanth Solution --------------------- 300Øcc Anionic Wetting Agent ----------------------- 400.0 cc ~
Octyl AlcohoI ------------------------------- 49.0 cc :
In examples E, F, and G the gum tragacanth solution ', , has tha following composition:
Gum Tragacanth Powder ----------------------- L~445 Gr Sodium Benzoate ----------------------------- 5 Gr .
Water --------------------------------------- 20,000 Gr ,. -:~ - .. . ~ . .
As the anionic wetting agent, use can be made of sodium `~
heptadecyl sulphate, such as Tergitol Anionic No. 7 of Union Carbide Corporation.
','' '. '~ ' ~ -t~ ~Je~ a r.~ _7_ ,', .! . ` i ; 1~ . . ' Representative of the antifoam colloids which may be -`-used in the above formulations is Antifoam Colloid No. 581B
produced by Colloids, Inc., ~ewark, ~ew Jersey.
Application of Second Dipcoat Composition The second dipcoat composition is applied to the coat-ed pattern in a manner similar to that of the first dipcoat com-position. A significant difference between the dipcoat compo-sitions is in the selection of the binder. The first dipcoat composition employs a colloidal silica binder. The second dip- -coat composition preferably utilizes an organic fugitive binder as, or examp:Le, polyvinyl alcohol. By organic fugitive binder it is possible to form a second intermediate layer about the pattern, and at a subsequent time drive off the binder to leave the intermediate layer closely packed but unbound.
In the preferred practice of this invention~ it is de-sired, although not essential, to precede the emersion of the coated pattern into the first and second dipcoat compositions with a pre-wetting step in which the pre-wetting composition employs substantially the same formulation as the dipcoat com-position, with the exception that a lower viscosity is employed.
me pre-wetting composition includes additional amounts of water sufficient to reduce the total solids to about 25% to 75% of the total solids in the dipcoat composition. Thus, the coated pattern, having the inner layer 12 dried thereon, is submerged into a pre-wetting composition more completely to penetrate and wet out the coated surface prior to being immersed in the second dipcoat composition. Immersion into the second dipcoat compo-sition follows immediately after the pre-wet immersion.
After the immersion in the second dipcoat composition, 3 the pattern is again allowed to drain and is stuccoed and dried.
.- . , .. ;:. . . : ~ :
:IV39925 "`
The steps of pre-wetting, dipcoating, stuccoing and drying are repeated one or more times, as necessary, to build up the inter-mediate layer 14 to a desired thickness. me stucco employed for the intermediate layer may be the same as that employed for the inner layer.
For special applications and particularly where large molds are utilized, it is desirable to add a very small percent-age, on the order of 0.125% by weight, of colloidal silica binder to the second dipcoat composition which also contains the organic fugitive binder as previously discussed. m e pres-ence of the colloidal silica binder prevents the intermediate layer from becoming completely powdery after the fugitive bind-er is driven off as will be described. The small amount of silica binder added to the second dipcoat does not increase the strength or increase the task oE removal buk permits patching and repair of the mold should such operations be necessary. The following example illustrates the use of a small amount of sili-ca binder in the second dipcoat:
Example H. ;
Zircon Flour ----------------------------------- 154 Lbs Antifoam Colloid ------------------------------- 500 cc Anionic Wetting Agent -------------------------- 720 cc Colloidal Silica (30% Sol.) -------------------- 242 cc .: .' . .. .
Polyvinyl Alcohol (7.26% Sol.) ----------------- 30.0 Lbs Water ------------------------------------------ 18.7 Lbs ;-Third Dipcoat Composition and Application `
~ . . . .
The composition of the third dipcoat, which forms the outer layer 16 of the mold can, but need not be, the same ~;
as the composition of the first dipcoat. It is applied and r ; `
3 stuccoed in a manner similar to that of the first dipcoat.
. . .
'-:
_g_ ' ~0399~5 However, usually a coarser stucco is applied. When the outer layer 16 has been built up to a desired thickness the mold is subjected to a final arying cycle.
As an example of the number of dipcoats required to form each of the three layers of the sandwich structure for an average weight casting, two dipcoatings have been employed to form the inner layer 12, three dipcoatings have been employed to form the intermediate layer 14, followed by two dipcoats in the first dipcoat composition to form the outer layer 16. For heavier castings or for large molds, the thickness of the lay-ers may be increased as necessary.
After final drying, the completed mold is heated toremove the pattern contained therein, and laave a mold cavity in which the material to be cast is poured. Pattern removal, hereinafter referred to as dewaxing, can be achieved in a num-ber of ways. Usually dewaxing the mold is accomplished by firing it to a high temperature. During such heating, the col-loidal silica binder in the inner and outer layers 12 and 16 strongly bonds the ceramic dipcoat and granular stucco into a monolithic mass. Simultaneously, the organic fugitive binder in the intermediate layer 14 is volatilized and/or burned out leaving the materials making up the intermediate layer unbond-ed and sandwiched between the inner and outer bonded layers.
Alternately, the sandwich structure mold of the pres-ent invention can be dewaxed at a lower temperature on theorder of 200 to 400 F. This dewaxing method is possible due to the high green strength achieved in the present sandwich structure mold.
If the sandwich mold is dewaxed at a low temperature, then it will be preheated to a high temperature prior to use~
,. . .
-10- '-~039925 ` `
as indicated in Fig. 2, for burning out the mold, i.e., remov- -ing any small traces of remaining wax, for burning out or vola- -~' ' ' !, . . .
tilizing the organic binder used for the intermediate layer and for curing the silica binder. Preheating is usually car- --ried out at temperatures in the range of 1000 to 2850 F.
me sandwich structure mold, after being preheated, is ready for pouring the molten metal in the mold cavity. Dur-ing the preheating and pouring of the metal, the sandwich struc-ture mold does not gain sufficient additional strength to cause excessive hardening of the mold. Another advantage of a sand-wich structure mold is that, during the cooling process, the `
relatively thin inner layer 12 is able to collapse, thereby ^ `~
eliminating the possibility of casting hot tears.
After the casting has cooled completely, the mold is ~`
removed. Its construction permits the use of low amplitude me-chanical vibration to crack the thin outer layer 16, which breaks off easily. The intermediate layer, being unbound, falls away from the mold and, if desired, may be reclaimed for re-use.
me portions of the inner layer are similarly easily broken away.
The castings resulting from this process are rela-tively free of mold materials, hot tears, and knock-out cracks. -Also, sand blasting for final cleaning is minimized.
While I have shown and described an embodiment of this invention in some detail, it will be understood that this de- `
scription and illustration are offered merely by way of example, and that the invention is to be limited in scope only by the appended claims.
'',., '`
-11- .
Claims (16)
1. A method of producing a recyclable sandwich struc-ture monolithic mold about a disposable pattern which is removed to define a mold cavity comprising the steps of:
(a) wetting the surface of the pattern with a first dipcoat composition, the essential solids of which con-sist of finely divided refractory material, including an in organic binder;
(b) covering the surface of the pattern, while wet with the first dipcoat, with a granular refractory stucco;
(c) repeating, at least once, steps (a) and (b) with intervening drying to form a first layer of said mold;
(d) wetting said first layer with a second dip-coat composition, the essential ingredients including finely divided refractory material and an organic fugitive binder;
(e) covering the surface of the first layer while wet with the second dipcoat with a granular refractory stucco;
(f) repeating, at least once, steps (d) and (e) with intervening drying to form an intermediate layer of said mold; and (g) forming an outer layer over said intermediate layer in the manner recited in steps (a), (b) and (c), to there-by produce a three layer sandwich structure mold.
(a) wetting the surface of the pattern with a first dipcoat composition, the essential solids of which con-sist of finely divided refractory material, including an in organic binder;
(b) covering the surface of the pattern, while wet with the first dipcoat, with a granular refractory stucco;
(c) repeating, at least once, steps (a) and (b) with intervening drying to form a first layer of said mold;
(d) wetting said first layer with a second dip-coat composition, the essential ingredients including finely divided refractory material and an organic fugitive binder;
(e) covering the surface of the first layer while wet with the second dipcoat with a granular refractory stucco;
(f) repeating, at least once, steps (d) and (e) with intervening drying to form an intermediate layer of said mold; and (g) forming an outer layer over said intermediate layer in the manner recited in steps (a), (b) and (c), to there-by produce a three layer sandwich structure mold.
2. The method of claim 1 further including the step of volatilizing the organic fugitive binder to leave the inter-mediate layer unbound and sandwiched between said inner and outer layers.
3. The method of claim 1 wherein the organic fugi-tive binder is polyvinyl alcohol.
4. The method of claim 1 wherein the organic fugi-tive binder is one of the group comprising vegetable gums, starches and polymeric latices.
5. The method of claim 1, further including the steps of (a) removing said pattern; and (b) heating said mold to a temperature sufficient to volatilize said organic fugitive binder to leave said inter-mediate layer unbound.
6. The method of claim 1 further including the steps of heating said mold to remove said disposable pattern, to vol-atilize said organic fugitive binder in said intermediate layers, and to fuse said inorganic binder in said inner and outer layers.
7. The method according to claim 5 wherein the step of removing the pattern is accomplished at a temperature within the range of 200° to 400° F., and the step of volatilizing the organic fugitive binder is accomplished at a temperature within the range of 1000°F. to 2850°F.
8. A sandwich structure recyclable monolithic mold for precision casting having a wall structure in cross-section comprising:
(a) an inner layer consisting essentially of fine-ly divided refractory material, including an inorganic binder and granular refractory stucco;
(b) an intermediate layer consisting essentially of finely divided refractory material, refractory stucco and an organic fugitive binder;
(c) an outer layer identical in composition to said inner layer.
(a) an inner layer consisting essentially of fine-ly divided refractory material, including an inorganic binder and granular refractory stucco;
(b) an intermediate layer consisting essentially of finely divided refractory material, refractory stucco and an organic fugitive binder;
(c) an outer layer identical in composition to said inner layer.
9. The mold of claim 8 wherein prior to use the mold is subjected to heating sufficient to volatilize said organic fugitive binder, to thereby leave the intermediate layer refractory material and stucco unbound and sand-wiched between the bound inner and outer layers.
10. The mold of claim 8 wherein the inner and outer layer refractory materials and stucco essentially comprise ceramic flour and binder and ceramic stucco.
11. The mold of claim 8 wherein the intermediate layer refractory mater-ials essentially comprise alumina or zircon flour.
12. The mold of claim 8 wherein the organic fugitive binder is selected from the group comprising vegetable gums, starches, polymeric latices and polyvinyl alcohol.
13. A method of precision casting materials comprising the steps of:
(a) producing a recyclable sandwich structure monolithic mold about a disposable pattern by the method of claim 1;
(b) removing said disposable pattern from said mold to provide a mold cavity;
(c) firing said mold to a temperature sufficient to volatilize said organic fugitive binder to thereby leave said intermediate layer unbound and sandwiched between the bound inner and outer layers;
(d) pouring a molten metal alloy into said mold cavity;
(e) cooling the mold;
(f) removing the mold from the cast metal alloy.
(a) producing a recyclable sandwich structure monolithic mold about a disposable pattern by the method of claim 1;
(b) removing said disposable pattern from said mold to provide a mold cavity;
(c) firing said mold to a temperature sufficient to volatilize said organic fugitive binder to thereby leave said intermediate layer unbound and sandwiched between the bound inner and outer layers;
(d) pouring a molten metal alloy into said mold cavity;
(e) cooling the mold;
(f) removing the mold from the cast metal alloy.
14. The method of claim 13 wherein the disposable pattern is formed of wax and steps (b) and (c) are accomplished simultaneously by the heating of said mold to a temperature within the range of 1000° to 2850°F.
15, The method of claim 13 wherein step (f) includes the sub-steps of:
(a) breaking the outer layer with low amplitude mechanical vibration;
(b) permitting the unbound intermediate layer to fall away from the mold and collecting for re-use;
(c) removing the inner layer.
(a) breaking the outer layer with low amplitude mechanical vibration;
(b) permitting the unbound intermediate layer to fall away from the mold and collecting for re-use;
(c) removing the inner layer.
16. A sandwich structure mold according to claim 9 wherein said inter-mediate layer also includes approximately 0.125% by weight of an inorganic binder for preventing said intermediate layer from becoming completely unbound when said organic fugitive binder is volatilized.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US427732A US3903950A (en) | 1973-12-26 | 1973-12-26 | Sandwich structure mold |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1039925A true CA1039925A (en) | 1978-10-10 |
Family
ID=23696039
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA215,015A Expired CA1039925A (en) | 1973-12-26 | 1974-12-02 | Sandwich structure monolithic mold |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US3903950A (en) |
| JP (1) | JPS5223883B2 (en) |
| BE (1) | BE823853A (en) |
| CA (1) | CA1039925A (en) |
| FR (1) | FR2255977B1 (en) |
| GB (1) | GB1486326A (en) |
| IT (1) | IT1026158B (en) |
| SE (1) | SE420799B (en) |
Families Citing this family (20)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4689081A (en) * | 1982-09-30 | 1987-08-25 | Watts Claude H | Investment casting method and stucco therefor |
| FR2556623B1 (en) * | 1983-12-14 | 1986-05-09 | Ucpi | LOST MODEL MOLDING PROCESS FOR METALS, MOLDS FOR CARRYING OUT SAID METHOD AND MANUFACTURING METHOD THEREOF |
| EP0153432A1 (en) * | 1984-02-29 | 1985-09-04 | Dentsply International, Inc. | Artificial stuccs material,process for making it and use thereof |
| US4834165A (en) * | 1987-08-03 | 1989-05-30 | Ryobi Ltd. | Collapsible core and method for producing the collapsible core feasible for high speed high pressure casting |
| FR2649917A1 (en) * | 1989-07-20 | 1991-01-25 | Snecma | PROCESS FOR THE MANUFACTURE OF SHELL MOLDS FOR FOUNDRY |
| US5284620A (en) * | 1990-12-11 | 1994-02-08 | Howmet Corporation | Investment casting a titanium aluminide article having net or near-net shape |
| US5297615A (en) * | 1992-07-17 | 1994-03-29 | Howmet Corporation | Complaint investment casting mold and method |
| CN1050786C (en) * | 1994-03-15 | 2000-03-29 | 伊藤南己 | Wax-like substance and molding method by using wax-like... |
| GB9601910D0 (en) * | 1996-01-31 | 1996-04-03 | Rolls Royce Plc | A method of investment casting and a method of making an investment casting mould |
| EP1266706A1 (en) * | 2001-06-13 | 2002-12-18 | Siemens Aktiengesellschaft | Casting apparatus, process for producing a casting apparatus and its use |
| JP6095934B2 (en) * | 2012-10-09 | 2017-03-15 | 三菱日立パワーシステムズ株式会社 | Precision casting mold manufacturing method |
| JP6199019B2 (en) * | 2012-10-09 | 2017-09-20 | 三菱日立パワーシステムズ株式会社 | Precision casting mold manufacturing method |
| JP6095933B2 (en) * | 2012-10-09 | 2017-03-15 | 三菱日立パワーシステムズ株式会社 | Precision casting mold manufacturing method |
| JP6199018B2 (en) * | 2012-10-09 | 2017-09-20 | 三菱日立パワーシステムズ株式会社 | Precision casting mold manufacturing method |
| JP6095935B2 (en) * | 2012-10-09 | 2017-03-15 | 三菱日立パワーシステムズ株式会社 | Precision casting mold manufacturing method |
| US11786961B2 (en) * | 2015-10-13 | 2023-10-17 | Metal Casting Technology, Inc. | Investment mold slurry curtain apparatus |
| MX2019004103A (en) | 2016-10-10 | 2019-07-15 | 3M Innovative Properties Co | Method of making investment casting mold. |
| WO2018085560A1 (en) | 2016-11-03 | 2018-05-11 | 3M Innovative Properties Company | Investment casting compositions, molds, and related methods |
| WO2019016741A1 (en) | 2017-07-20 | 2019-01-24 | 3M Innovative Properties Company | Investment casting compositions, molds, and related methods |
| CN113857423B (en) * | 2021-08-31 | 2023-09-08 | 宝鸡昆吾创新技术有限公司 | Adhesive for casting and preparation method thereof |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2912729A (en) * | 1956-07-24 | 1959-11-17 | John M Webb | Refractory molds |
| US3011986A (en) * | 1958-09-12 | 1961-12-05 | Howe Sound Co | Dip coat composition for metal casting comprising ceramic flour, colloidal silica, gum, alkali metal fluoride and rubber latex |
| US3239897A (en) * | 1963-09-20 | 1966-03-15 | Howe Sound Co | Precision casting mold and methods and materials for production and use |
| US3256574A (en) * | 1965-03-22 | 1966-06-21 | Howe Sound Co | Mold and method of fabrication |
-
1973
- 1973-12-26 US US427732A patent/US3903950A/en not_active Expired - Lifetime
-
1974
- 1974-11-25 GB GB50932/74A patent/GB1486326A/en not_active Expired
- 1974-12-02 CA CA215,015A patent/CA1039925A/en not_active Expired
- 1974-12-17 FR FR7441463A patent/FR2255977B1/fr not_active Expired
- 1974-12-18 JP JP49144586A patent/JPS5223883B2/ja not_active Expired
- 1974-12-19 SE SE7416046A patent/SE420799B/en unknown
- 1974-12-24 IT IT54755/74A patent/IT1026158B/en active
- 1974-12-24 BE BE151925A patent/BE823853A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| US3903950A (en) | 1975-09-09 |
| JPS5223883B2 (en) | 1977-06-28 |
| DE2459088B2 (en) | 1976-02-19 |
| SE7416046L (en) | 1975-06-27 |
| FR2255977B1 (en) | 1984-02-17 |
| SE420799B (en) | 1981-11-02 |
| FR2255977A1 (en) | 1975-07-25 |
| DE2459088A1 (en) | 1975-07-03 |
| BE823853A (en) | 1975-04-16 |
| GB1486326A (en) | 1977-09-21 |
| JPS5097519A (en) | 1975-08-02 |
| IT1026158B (en) | 1978-09-20 |
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