US3830279A - Method and apparatus for forming sand molds - Google Patents

Method and apparatus for forming sand molds Download PDF

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Publication number
US3830279A
US3830279A US00040487A US4048770A US3830279A US 3830279 A US3830279 A US 3830279A US 00040487 A US00040487 A US 00040487A US 4048770 A US4048770 A US 4048770A US 3830279 A US3830279 A US 3830279A
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United States
Prior art keywords
pattern
mold
support plate
casting
support member
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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 - Lifetime
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US00040487A
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English (en)
Inventor
H Arbenz
W Baumgartner
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Alcan Holdings Switzerland AG
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Alusuisse Holdings AG
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Publication date
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Publication of US3830279A publication Critical patent/US3830279A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C7/00—Patterns; Manufacture thereof so far as not provided for in other classes
    • B22C7/005—Adjustable, sectional, expandable or flexible patterns
    • 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
    • B22C9/03—Sand moulds or like moulds for shaped castings formed by vacuum-sealed moulding

Definitions

  • sand or sand mixtures are molding substances which are generally used in aluminum casting plants (green molding sand). If one desires to obtain very large molds with a sufficient degree of mechanical resistance, one will have to resort to using mixtures which are capable of being hardened.
  • the hardening can be brought about through certain admixtures for example, by blowing a gas into the molding substance such as, for example, carbon dioxide, or said hardening process can take place by itself after a more or less long incubation period, for example, when cement is admixed.
  • so called mold-masks CRONING method
  • each segment of the mold must be constructed with tapered pattern parts (draft), that is, the surfaces which delineate the mold cavity must be pointed everywhere in such a direction, that the pattern or its parts can be withdrawn from the mold, without the mold being damaged thereby. If there is only an insufficient taper or no taper at all at one section of the mold (the angle between the mold surface in question and the direction of pattern withdrawal), or if the surfaces of the pattern, and consequently those of the mold cavity, are not smooth, one will be forced to divide the pattern into several parts which can be removed individually from the mold, without the latter being damaged thereby. This involves a costly complication with respect to the manufacturing process itself, as well as with respect to subsequent repairs of the mold, said repair jobs being usually necessary in order to remove traces of joints between various pattern parts which are visible on the surface of the mold.
  • draft tapered pattern parts
  • Another object of the invention is to eliminate damage to the mold patterns and hence reduce overall costs.
  • the invention is characterized that in place of the customary pattern set-up, a pattern is utilized which consists of a flexible material which can be bent in all directions, with said flexible pattern resting on a pattern supporting member.
  • Such a pattern which is made of a.bendable, but also elastic material and which generally possesses a large surface anda slight thickness, must come to rest on a pattern supporting member, against the surface of which in a preferred embodiment it tightly clings.
  • the surface of the pattern supporting member corresponds moreover to the shape of the underside of the thin casting piece which is to be subsequently produced.
  • the flexible pattern in different shapes leads only thento the prescribed dimensions of the metallic piece to be cast, when said flexible pattern tightly clings to the shape of the pattern supporting member.
  • the pattern can be bent and deformed due to its flexibility, these deformations being reversible, for example, after withdrawal of the pattern from the mold.
  • the pattern must come to lie at each point, as close as possible against the pattern supporting member.
  • the flexible pattern may be positioned quickly and simply against the pattern support member, namely with a precision which is required for the production of the mold. Air cushions between the two surfaces, which touch one another, are thereby avoided.
  • the free-venting surface of the pattern support member may be comprised of a porous material such as, for example, a combination of wood chips and synthetic resin or of calcined clay and gypsum, also selfhardening and porous concrete.
  • a porous material such as, for example, a combination of wood chips and synthetic resin or of calcined clay and gypsum, also selfhardening and porous concrete.
  • the shape of this surface corresponds to that of the underside of the metallic sheet to be produced.
  • the material which serves for making the pattern can be a natural or synthetic, more or less hardened rubber, or can be a synthetic resin which had been treated by a known method in order to impart the necessary flexibility to it. It may also be a composite material such as, for example, a combination of cork and rubber, or any other simple or composite material which has the required characteristics, especially flexibility. In addition, said material must also possess a certain resistance to compression. The demands made of this material, however, are kept within rather narrow limits, especially if molds are produced by a method which is based on a self-hardening combination, which consists of a quick-hardening coating layer and a slower hardening supplementary filling.
  • the mold is produced in a known manner, namely, from mixtures which are capable of hardening or setting.
  • quartz, zicron, or olivine (chrysolite) sand can be utilized together with a polymerizing binding medium, which brings about hardening in less than 1 hour. As far as the hardening process is concerned, one can also make.
  • This method consists therein, in that a quick hardening suspension is initially applied onto the surface of the mold, which in a preparatory step had already been coated with an anti-adhesive medium such as paraffin, glycerine, kerosene, etc.
  • an anti-adhesive medium such as paraffin, glycerine, kerosene, etc.
  • Such suspensions are applied with a brush or are sprayed on in the form of a thin layer and in a short time form a hard compact mask.
  • a required quantity of casting sand such as, for example, a mixture of quartz sand. sodium silicate. serving as a binding medium and a suitable hardener so that a compact total unit is formed which displays the desired thickness.
  • this thickness can be in the order of 5 cm or more.
  • One of the following substances can serve as the hardener: sodium fluosilicate, sodium aluminate, bicalcium silicate, sodium zirconium disilicate, etc.
  • FIG. 1 is a horizontal sectional view of a device for sand casting of metallic objects
  • FIG. 2 is a horizontal fragmentary sectional view similar to FIG. 1 but showing the system of FIG. I turned over and the pattern support member withdrawn from the mold;
  • FIG. 3 is a horizontal sectional view showing the production of the upper mold half with the filling system
  • FIG. 4 is a horizontal fragmentary sectional view showing the manner in which the flexible pattern is removed from the two mold halves.
  • FIG. 5 is a horizontal sectional view showing the last phase.
  • a pattern support member (2) is placed on the workroom floor or onto a stationary or movable mold base (1
  • the surface of this pattern support member (2) in a preferred embodiment is penetrable by air (free-venting) and corresponds to the shape of the generally smooth underside of the metal sheet to be cast.
  • a flexible casting pattern (3) is placed, which then represents an exact prototype of the metal sheet to be cast.
  • it is made of a material which possesses a certain flexibility, said material being rubber, a corresponding synthetic resin, or another material.
  • the flexible pattern (3) can be adapted with perforations (4), should the architectural concept provide for such perforations. These perforations can serve for the accurate placement of gate elements (9) which are to be mounted on the pattern support member (2) and which form a filling system.
  • conduits (5) are hollowed out in the pattern support member (2), said conduits (5 being connected to an air suction device (for example, a vacuum pump, not shown) for creating an under pressure.
  • an air suction device for example, a vacuum pump, not shown
  • a casting box or enclosure (6) which is equipped with customary supplementary means for correct positioning and mounting, is placed on top of the pattern support member (2) by means of guide pins (10).
  • the casting box (6) is filled with a suitable molding material (8), which is capable of hardening and which, in customary manner, is fitted against the rough surface of the flexible pattern (3) which is molded in relief form, so that one ultimately obtains a mold cavity which corresponds to the shape of the flexible pattern (3).
  • a suitable molding material (8) which is capable of hardening and which, in customary manner, is fitted against the rough surface of the flexible pattern (3) which is molded in relief form, so that one ultimately obtains a mold cavity which corresponds to the shape of the flexible pattern (3).
  • any material which is capable of being hardened and which is usable in the production of sand casting molds can be utilized.
  • the casting box (6) When the molding material (8) has reached the desired degree of hardness, the casting box (6), with its contents is turned over. Subsequently, normal atmospheric pressure is re-established in the pattern support member (2), which enables one to separate the hardened mold from the member (2), whereby the flexible pattern (3) remains in position. In other words, the flexible pattern (3) adheres to the surface of the mold half which is located in the casting box (6) and now forms the base portion.
  • an upper casting box 11 is set on top of the lower casting box (6).
  • Additional supplementary mold components can be added, such as reinforcing ribs and eyelets for ultimate fastening of the finished product.
  • the upper segment of the mold is produced, namely by filling the upper casting box (11) with a suitable material (8), which can be of the same type as the one used in the lower casting mold (6) or can also have another composition.
  • a suitable material (8) which can be of the same type as the one used in the lower casting mold (6) or can also have another composition.
  • ordinary green casting sand can be used for the upper mold half, or one can use a sand which subsequently can be dried.
  • the upper casting box (11) is lifted off and the supplementary mold components (12), (13) if used, are removed.
  • the flexible pattern (3) is lifted from the bottom mold half with all necessary care, in order to separate it from the relief-bearing mold surface.
  • the mold segments corresponding to the gates are likewise removed from the bottom mold half.
  • the metal casting takes place through a filling funnel or other suitable means (12).
  • the operation begins directly with the following step; namely, one in which the above-mentioned casting box (6) is brought into the position which it takes up in accordance with FIG. 2, that is, the casting box (6) is placed on the floor or on another foundation or base (1).
  • the casting box (6) is filled with the suitablemolding material (8) and the mold cavity (14) is formed by pressing the pattern support plate (2) to which, owing to the under pressure, the flexible pattern (3) adheres onto the molding material.
  • a preforming process should be undertaken with the aid of a supplementary tool, forexample with the aid of a template.
  • the casting box (6) will have to be filled partially, that is, up to a level which lies somewhat higher than its surface at the end of the working cycle, so that at all points where the pattern presses against the molding material in order to create the mold cavity (14), a slight consolidation of the molding material (8) takes place. This is necessary in order that the surface of the flexible pat tern (3) is accurately reproduced all over.
  • a method for the manufacture of hardened molds for sand casting metallic objects especially those having a large surface and a slight thickness, such as wall panels of aluminum and its alloys,
  • a mold pattern composed of an elastic and flexible material and a pattern support plate of a rigid material and creating under pressure between said mold pattern and said pattern support plate while forming a mold half on the other face of said mold pattern.
  • a mold pattern composed of an elastic and flexible material, a rigid pattern support plate, a face of said pattern support plate conforming to the desired shape of the back surface of the object to be cast, the pattern support plate being permeable to air in the region of its shaped face and containing a system of internal air ducts, and means for applying a vacuum to the ducts so that the mold pattern is positively held in close contact with the whole of the shaped face of the pattern support plate while a mold half is formed on the outer face of the mold pattern.
  • said casting pattern is of a composite material selected from the group consisting of rubber-cork and rubbersynthetic resins.
  • said casting pattern is of a material selected from the group consisting of natural and synthetic rubbers.
  • said support plate comprises an internal conduit system and a plurality of vents between said conduit system and said shaped surface thereof.
  • said pattern support plate has a plurality of perforations or pores.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Molds, Cores, And Manufacturing Methods Thereof (AREA)
  • Casting Devices For Molds (AREA)
  • Mold Materials And Core Materials (AREA)
  • Electrolytic Production Of Metals (AREA)
US00040487A 1969-05-28 1970-05-26 Method and apparatus for forming sand molds Expired - Lifetime US3830279A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH806369A CH488503A (fr) 1969-05-28 1969-05-28 Procédé de fabrication de moules pour la coulée en sable de pièces métalliques

Publications (1)

Publication Number Publication Date
US3830279A true US3830279A (en) 1974-08-20

Family

ID=4334565

Family Applications (1)

Application Number Title Priority Date Filing Date
US00040487A Expired - Lifetime US3830279A (en) 1969-05-28 1970-05-26 Method and apparatus for forming sand molds

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Country Link
US (1) US3830279A (forum.php)
JP (1) JPS4930610B1 (forum.php)
AT (1) AT308986B (forum.php)
BE (1) BE750889A (forum.php)
CH (1) CH488503A (forum.php)
DE (2) DE2026055A1 (forum.php)
DK (1) DK124519B (forum.php)
ES (1) ES380111A1 (forum.php)
FR (1) FR2064049B1 (forum.php)
GB (1) GB1256345A (forum.php)
IE (1) IE34195B1 (forum.php)
LU (1) LU60947A1 (forum.php)
NL (1) NL164492B (forum.php)
NO (1) NO131536C (forum.php)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3960198A (en) * 1975-04-25 1976-06-01 Mitsubishi Jukogyo Kabushiki Kaisha Reduced pressure mould production method
US4027723A (en) * 1975-01-20 1977-06-07 Precision Flexmold, Inc. Molding apparatus including a flexible mold for making articles having radially inwardly extending projections on an interior surface
US20050285176A1 (en) * 2004-06-24 2005-12-29 Sang-Ho Kim Semiconductor device having box-shaped cylindrical storage nodes and fabrication method thereof
US20090020254A1 (en) * 2007-07-16 2009-01-22 Waukesha Foundry, Inc. In-place cope molding for production of cast metal components
CN106607559A (zh) * 2015-10-23 2017-05-03 共享铸钢有限公司 水轮机叶片的砂型造型方法
EP3246107A1 (en) * 2016-05-20 2017-11-22 LuxMea Studio, LLC Method of investment casting using additive manufacturing

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US25157A (en) * 1859-08-16 Improvement in patterns for molding
US2306516A (en) * 1941-09-27 1942-12-29 Austenal Lab Inc Method of making hollow casting molds
US2391587A (en) * 1942-09-21 1945-12-25 Miller Engineering Corp Method of making molds having transition cores
FR926498A (fr) * 1946-04-13 1947-10-02 Reproduction Metallique Ind Procédé de fabrication de moules métalliques et produit industriel nouveau en résultant
US2867870A (en) * 1956-10-05 1959-01-13 Hines Flask Company Method and apparatus for making sand molds for castings
US3041669A (en) * 1959-10-19 1962-07-03 Gen Electric Vacuum forming apparatus
US3042969A (en) * 1959-11-23 1962-07-10 Goodyear Tire & Rubber Apparatus and method for manufacturing mats
GB962614A (en) * 1962-03-12 1964-07-01 John Pilling Improvements relating to casting methods
US3229338A (en) * 1965-03-31 1966-01-18 Kopera Joseph Manufacturing process for re-usable molds

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US25157A (en) * 1859-08-16 Improvement in patterns for molding
US2306516A (en) * 1941-09-27 1942-12-29 Austenal Lab Inc Method of making hollow casting molds
US2391587A (en) * 1942-09-21 1945-12-25 Miller Engineering Corp Method of making molds having transition cores
FR926498A (fr) * 1946-04-13 1947-10-02 Reproduction Metallique Ind Procédé de fabrication de moules métalliques et produit industriel nouveau en résultant
US2867870A (en) * 1956-10-05 1959-01-13 Hines Flask Company Method and apparatus for making sand molds for castings
US3041669A (en) * 1959-10-19 1962-07-03 Gen Electric Vacuum forming apparatus
US3042969A (en) * 1959-11-23 1962-07-10 Goodyear Tire & Rubber Apparatus and method for manufacturing mats
GB962614A (en) * 1962-03-12 1964-07-01 John Pilling Improvements relating to casting methods
US3229338A (en) * 1965-03-31 1966-01-18 Kopera Joseph Manufacturing process for re-usable molds

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4027723A (en) * 1975-01-20 1977-06-07 Precision Flexmold, Inc. Molding apparatus including a flexible mold for making articles having radially inwardly extending projections on an interior surface
US3960198A (en) * 1975-04-25 1976-06-01 Mitsubishi Jukogyo Kabushiki Kaisha Reduced pressure mould production method
US20050285176A1 (en) * 2004-06-24 2005-12-29 Sang-Ho Kim Semiconductor device having box-shaped cylindrical storage nodes and fabrication method thereof
US7273780B2 (en) * 2004-06-24 2007-09-25 Samsung Electronics Co., Ltd. Semiconductor device having box-shaped cylindrical storage nodes and fabrication method thereof
US20080035976A1 (en) * 2004-06-24 2008-02-14 Samsung Electronics Co., Ltd. Semiconductor device having box-shaped cylindrical storage nodes and fabrication method thereof
US20090020254A1 (en) * 2007-07-16 2009-01-22 Waukesha Foundry, Inc. In-place cope molding for production of cast metal components
US7900684B2 (en) 2007-07-16 2011-03-08 Waukesha Foundry, Inc. In-place cope molding for production of cast metal components
CN106607559A (zh) * 2015-10-23 2017-05-03 共享铸钢有限公司 水轮机叶片的砂型造型方法
CN106607559B (zh) * 2015-10-23 2018-09-18 共享铸钢有限公司 水轮机叶片的砂型造型方法
EP3246107A1 (en) * 2016-05-20 2017-11-22 LuxMea Studio, LLC Method of investment casting using additive manufacturing

Also Published As

Publication number Publication date
GB1256345A (en) 1971-12-08
BE750889A (fr) 1970-11-03
ES380111A1 (es) 1972-08-16
IE34195L (en) 1970-11-28
DE7019839U (de) 1971-02-11
JPS4930610B1 (forum.php) 1974-08-14
FR2064049B1 (forum.php) 1976-07-30
NO131536C (forum.php) 1975-06-18
AT308986B (de) 1973-07-25
DK124519B (da) 1972-10-30
DE2026055A1 (de) 1970-12-03
NL164492B (nl) 1980-08-15
NO131536B (forum.php) 1975-03-10
CH488503A (fr) 1970-04-15
IE34195B1 (en) 1975-03-05
NL7007004A (forum.php) 1970-12-01
LU60947A1 (forum.php) 1970-07-20
FR2064049A1 (forum.php) 1971-07-16

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