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WO1993005940A1 - Method of casting and reproduction and an article produced by this method - Google Patents

Method of casting and reproduction and an article produced by this method Download PDF

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Publication number
WO1993005940A1
WO1993005940A1 PCT/GB1992/001674 GB9201674W WO9305940A1 WO 1993005940 A1 WO1993005940 A1 WO 1993005940A1 GB 9201674 W GB9201674 W GB 9201674W WO 9305940 A1 WO9305940 A1 WO 9305940A1
Authority
WO
WIPO (PCT)
Prior art keywords
mould
water
article
amount
allowing
Prior art date
Application number
PCT/GB1992/001674
Other languages
French (fr)
Inventor
Peter Raymond Burt
Original Assignee
Peter Raymond Burt
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Peter Raymond Burt filed Critical Peter Raymond Burt
Priority to JP5505878A priority Critical patent/JPH06510712A/en
Priority to EP92919453A priority patent/EP0603277A1/en
Publication of WO1993005940A1 publication Critical patent/WO1993005940A1/en

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B33/00—Clay-wares
    • C04B33/24—Manufacture of porcelain or white ware
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B1/00—Producing shaped prefabricated articles from the material
    • B28B1/007—Producing shaped prefabricated articles from the material by freezing the material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B1/00—Producing shaped prefabricated articles from the material
    • B28B1/26—Producing shaped prefabricated articles from the material by slip-casting, i.e. by casting a suspension or dispersion of the material in a liquid-absorbent or porous mould, the liquid being allowed to soak into or pass through the walls of the mould; Moulds therefor ; specially for manufacturing articles starting from a ceramic slip; Moulds therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B1/00—Producing shaped prefabricated articles from the material
    • B28B1/26—Producing shaped prefabricated articles from the material by slip-casting, i.e. by casting a suspension or dispersion of the material in a liquid-absorbent or porous mould, the liquid being allowed to soak into or pass through the walls of the mould; Moulds therefor ; specially for manufacturing articles starting from a ceramic slip; Moulds therefor
    • B28B1/28—Producing shaped prefabricated articles from the material by slip-casting, i.e. by casting a suspension or dispersion of the material in a liquid-absorbent or porous mould, the liquid being allowed to soak into or pass through the walls of the mould; Moulds therefor ; specially for manufacturing articles starting from a ceramic slip; Moulds therefor involving rotation of the mould about a centrifugal axis
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B33/00—Clay-wares
    • C04B33/30—Drying methods

Definitions

  • This invention relates to methods of casting and reproduction of water-containing materials and in particu ⁇ lar, but not exclusively, to casting of clay bodies such as 5 porcelain, bone china, redware, stoneware etc.
  • the articles produced by the multipart moulding techniques can look flat and lifeless compared to their resin cast counterparts or one-off original designs.
  • a method of casting an article from a water-containing material which comprises the steps of:- (a) introducing a charge of said water-containing material into a mould of flexible or resiliently distortable material;
  • said method also includes the step of causing or allowing removal or separation of an amount of water from the charge in the mould before the mould is exposed to said reduced temperature.
  • the removal or separation may be achieved in a variety of ways.
  • the mould and its contents may be centrifuged to cause an amount of water to separate from the remainder of the material, thus forming a supernatant layer.
  • the mould and its contents may be left for a while to cause water to separate from the remainder of the material.as a consequence of natural settlement.
  • This natural settlement may be accelerated by vibrating the mould and its contents, for example on a vibrating table.
  • the mould and its contents may be left to allow water loss by evaporation until the mould contents reach a semi-dry condition. This may be accelerated by heating until the surface of the contents is semi-dry.
  • the water-containing material is preferably a ceramic and the part-formed or "green-formed" article is preferably fired following removal from the mould and drying.
  • the water- containing ceramic material may comprise a clay body such as porcelain or bone china, etc.
  • the formulation of the clay body, including the particle sizes and the various proportions of the constitu ⁇ ents may be adjusted as required to give a suitable pouring consistency without leaving voids in the mould.
  • the clay body may include a flocculant, for example aluminium sulphate, to assist settling-out of the clay body.
  • the clay body may be semi-solid or solid and pressed into the mould instead of being poured into it.
  • the water-containing material is preferably degassed prior to pouring into the mould, for example, by placing in an atmosphere at reduced pressure, e.g. in a vacuum tank.
  • the supernatant water (where present) is preferably removed from the mould prior to the freezing step.
  • the article to be moulded is bulky, it may be hollow cast by introducing into the mould a plug or core around which the water-containing material passes.
  • the plug or core may be a reduced size replica of the original article, which may be produced by the miniaturisation process defined below.
  • the above technique allows articles to be reproduced on a reduced scale whilst maintaining a high definition of detail.
  • the method preferably includes the step of causing or allowing removal of an amount of water from said charge in said mould before said mould is exposed to said reduced temperature.
  • the hardening or setting is preferably achieved by firing the material.
  • original is used to identify the article to be copied, and is not intended to exclude the possibility that the article is itself a copy.
  • the reduced size copy produced in step (f) may itself be used as an original in a subsequent process in which steps (a) to (f) are repeated as necessary to produce successive reductions in size.
  • the reverse of the above technique may be applicable in some circumstances.
  • a water- containing material is formed around an original article of flexible material, an amount of water is then separated from said water-containing material, the remaining water- containing material is then frozen, the flexible original is removed, and the water-containing material caused to harden or set and shrink thus producing a reduced size three-dimen ⁇ sional "negative" of a flexible original "positive".
  • Example 1 A series of silicone rubber moulds was prepared by carving original pieces and placing them in separate mould boxes into which was poured a silicone rubber and catalyst. Once the silicone rubber had cured, the original pieces were removed leaving the moulds ready for use.
  • a porcelain slip was selected with a "runny” consistency which could be po ⁇ red freely into the mould and be de-gassed relatively easily.
  • a suitable slip is "White Orchid Porcelain Slip” available from Bell Ceramics, Clermont, Florida, U.S.A., although many other materials may be formulated and used.
  • the slip was placed into a vacuum tank of the type used for de-gassing resins in resin casting processes for about 15 minutes to de-air it.
  • the slip was. poured into the moulds and . the moulds then returned to the vacuum tank for about 10 to 15 minutes.
  • the moulds were then placed into a centrifuge having a mean radius of about 0.75m and operating at between 40 and 80 rpm, for half an hour so that the constituent particles of the porcelain slip separated out from the excess water, with the majority of the water lying on the surface as supernatant fluid.
  • the moulds were removed from the centrifuge and the supernatant fluid poured off. The moulds were then placed into a freezer at temperature of about -10°C for between 1 and 2 hours until the mix was frozen. The frozen pieces were removed from the moulds and left for about 2 days to dry completely, ready to be fired. The dry pieces were fired in a kiln in the normal way. The finished pieces were typically 10% to 12% smaller than the original piece.
  • Example 2 The series of moulds of Example 1 were filled with de- aired porcelain mix and de-aired as previously and then left to dry for a period of a few days, depending on the volume of the moulds, until the top surface of the contents was semi-dry. The moulds were frozen, the frozen pieces were removed and allowed to dry before being fired as previously to produce the finished pieces.
  • the above techniques allow extremely complicated pieces to be cast in a single mould. . 5 Also, the techniques allow a design to be made smaller and this may be repeated as necessary progressively to reduce a design to a required size. Thus one of the finished pieces in the above example could be used as an "original" to produce a further silicone mould of reduced 10. size compared to the original mould which then produces a finished piece of further reduced size and so on.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Ceramic Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Dispersion Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Adornments (AREA)
  • Producing Shaped Articles From Materials (AREA)

Abstract

An article is cast by introducing a water-containing material such as porcelain slip into a flexible mould, removing or separating an amount of water from said slip by, e.g. centrifuging, settlement or evaporation, and thereafter freezing said mould and its contents to allow the green-formed article to be removed from the mould without damage. The green-formed article is allowed to dry and is then fired in the usual way. Freezing of the mould allows a finely detailed article with many undercut features to be cast from a clay body in a single mould.

Description

Method of casting and reproduction and an article produced by this method.
This invention relates to methods of casting and reproduction of water-containing materials and in particu¬ lar, but not exclusively, to casting of clay bodies such as 5 porcelain, bone china, redware, stoneware etc.
There are a variety of ways in which fine "artware" may be produced. It is known to cast resin mixes in finely detailed silicone rubber moulds to produce articles with correspondingly fine detail. To produce such articles from 10. porcelain or china it has been necessary to use multipart rigid moulds to cast different parts of the article which are then assembled and finished by a skilled craftsman and this has made production complicated, time-consuming and costly. Moreover the multipart moulding techniques cannot 15 cope with designs incorporating many undercut features.
As a result the articles produced by the multipart moulding techniques can look flat and lifeless compared to their resin cast counterparts or one-off original designs.
Although the resin casting technique allows finely 0 detailed articles to be cast in resin, ceramic articles are still preferred and seen as being of premium quality and are - of food grade.
A need thus exists for a method which allows ceramic and other materials to be cast in quantity to produce finely - 5 detailed articles, without using multipart moulds.
Accordingly, in one aspect, there is provided a method of casting an article from a water-containing material which comprises the steps of:- (a) introducing a charge of said water-containing material into a mould of flexible or resiliently distortable material;
(b) exposing said mould and the material therein to a reduced temperature at least partially to freeze said material;
. (c) removing said material from said mould whilst at least partially frozen, and
(d) causing or allowing said material to dry, harden or set after removal from said mould.
Preferably, said method also includes the step of causing or allowing removal or separation of an amount of water from the charge in the mould before the mould is exposed to said reduced temperature. The removal or separation may be achieved in a variety of ways. The mould and its contents may be centrifuged to cause an amount of water to separate from the remainder of the material, thus forming a supernatant layer.
Alternatively, the mould and its contents may be left for a while to cause water to separate from the remainder of the material.as a consequence of natural settlement. This natural settlement may be accelerated by vibrating the mould and its contents, for example on a vibrating table.
Yet further, the mould and its contents may be left to allow water loss by evaporation until the mould contents reach a semi-dry condition. This may be accelerated by heating until the surface of the contents is semi-dry. The water-containing material is preferably a ceramic and the part-formed or "green-formed" article is preferably fired following removal from the mould and drying. The water- containing ceramic material may comprise a clay body such as porcelain or bone china, etc. The formulation of the clay body, including the particle sizes and the various proportions of the constitu¬ ents may be adjusted as required to give a suitable pouring consistency without leaving voids in the mould. Depending on the particular method to be employed, the clay body may include a flocculant, for example aluminium sulphate, to assist settling-out of the clay body.
In alternative techniques according to the invention, the clay body may be semi-solid or solid and pressed into the mould instead of being poured into it. The water-containing material is preferably degassed prior to pouring into the mould, for example, by placing in an atmosphere at reduced pressure, e.g. in a vacuum tank.
The supernatant water (where present) is preferably removed from the mould prior to the freezing step. Where the article to be moulded is bulky, it may be hollow cast by introducing into the mould a plug or core around which the water-containing material passes. In some arrangements, the plug or core may be a reduced size replica of the original article, which may be produced by the miniaturisation process defined below.
There is often a requirement to reproduce articles on a different scale, for example, when making sets of jewel¬ lery etc. I have found that when the above technique is applied to casting ceramic materials there is a net shrink¬ age of the finished article typically of between 10% and 12% (though this may vary with the selection of suitable materials) . Accordingly, in another aspect of this invention, there is provided a method of reproducing an article on a reduced scale, which comprises the steps of:-
(a) forming a complementary mould of flexible or resiliently distortable material around an original article; (b) removing said original article, leaving a formed mould;
(c) introducing a charge of water-containing material into the formed mould;
(d) exposing said mould and the material therein to. a reduced temperature at least partially to freeze said material;
(e) removing said material from said mould whilst still at least partially frozen, and
(f) causing or allowing said material to harden or set and shrink after removal from said mould thereby to form a reduced size copy of said original article.
The above technique allows articles to be reproduced on a reduced scale whilst maintaining a high definition of detail. The method preferably includes the step of causing or allowing removal of an amount of water from said charge in said mould before said mould is exposed to said reduced temperature. The hardening or setting is preferably achieved by firing the material.
The term "original" is used to identify the article to be copied, and is not intended to exclude the possibility that the article is itself a copy.
The reduced size copy produced in step (f) may itself be used as an original in a subsequent process in which steps (a) to (f) are repeated as necessary to produce successive reductions in size. The reverse of the above technique may be applicable in some circumstances. In such a preferred process, a water- containing material is formed around an original article of flexible material, an amount of water is then separated from said water-containing material, the remaining water- containing material is then frozen, the flexible original is removed, and the water-containing material caused to harden or set and shrink thus producing a reduced size three-dimen¬ sional "negative" of a flexible original "positive".
Example 1 A series of silicone rubber moulds was prepared by carving original pieces and placing them in separate mould boxes into which was poured a silicone rubber and catalyst. Once the silicone rubber had cured, the original pieces were removed leaving the moulds ready for use. A porcelain slip was selected with a "runny" consistency which could be poμred freely into the mould and be de-gassed relatively easily. A suitable slip is "White Orchid Porcelain Slip" available from Bell Ceramics, Clermont, Florida, U.S.A., although many other materials may be formulated and used.
The slip was placed into a vacuum tank of the type used for de-gassing resins in resin casting processes for about 15 minutes to de-air it. The slip was. poured into the moulds and.the moulds then returned to the vacuum tank for about 10 to 15 minutes. The moulds were then placed into a centrifuge having a mean radius of about 0.75m and operating at between 40 and 80 rpm, for half an hour so that the constituent particles of the porcelain slip separated out from the excess water, with the majority of the water lying on the surface as supernatant fluid.
The moulds were removed from the centrifuge and the supernatant fluid poured off. The moulds were then placed into a freezer at temperature of about -10°C for between 1 and 2 hours until the mix was frozen. The frozen pieces were removed from the moulds and left for about 2 days to dry completely, ready to be fired. The dry pieces were fired in a kiln in the normal way. The finished pieces were typically 10% to 12% smaller than the original piece.
Example 2 The series of moulds of Example 1 were filled with de- aired porcelain mix and de-aired as previously and then left to dry for a period of a few days, depending on the volume of the moulds, until the top surface of the contents was semi-dry. The moulds were frozen, the frozen pieces were removed and allowed to dry before being fired as previously to produce the finished pieces.
The above techniques allow extremely complicated pieces to be cast in a single mould. . 5 Also, the techniques allow a design to be made smaller and this may be repeated as necessary progressively to reduce a design to a required size. Thus one of the finished pieces in the above example could be used as an "original" to produce a further silicone mould of reduced 10. size compared to the original mould which then produces a finished piece of further reduced size and so on.

Claims

Claims 1. A method of casting, an article from a water- containing material, comprising the steps of:-
(a) introducing a charge of said water-containing material into a mould of flexible or resiliently distortable material;
(b) exposing said mould and the material therein to a reduced temperature at least partially to freeze said material; (c) removing said material from said mound whilst at least partially frozen, and
(d) causing or allowing said material to harden or set after removal from said mould.
2. A method according to Claim 1, further including the step of causing or allowing removal or separation of an amount of water from said charge in said mould before said mould is exposed to said reduced temperature.
3. A method according to Claim 2, wherein said amount of water is separated by centrifuging said mould and its contents. . A method according to Claim 2, wherein said amount of water is separated by allowing the material to settle for a period sufficient to allow an amount of water to separate from the material. 5. A method according to Claim 4, wherein said mould is vibrated during said settling period.
6. A method according to Claim 2, wherein said amount of water is separated by allowing it to evaporate from the surface of the material in the mould.
7. A method according to any preceding Claim, wherein said water-containing material is a clay body and is fired following removal from the mould. 5 8. A method according to Claim 7, wherein said clay body comprises porcelain, bone china, stoneware or earthen¬ ware.
9. A method according to Claim 7 or 8, wherein said clay body is a clay slip. 10 10. A method according to any preceding Claim, wherein the mould and its contents are degassed prior to freezing.
11. A method according to any preceding Claim, wherein a plug or core is introduced into the mould cavity to reduce the volume of the mould cavity. 15. 12. A method according to Claim 11, wherein said plug or core is a reduced size replica_.of said article.
13. A method according to Claim 2 or any Claim dependent thereon, wherein the separated water is removed from said mould prior to the freezing step. 0 14. A method of reproducing an original article on a reduced scale, which comprises the steps of:-
(a) forming a complementary mould of flexible or resiliently distortable material around said original article; 5 (b) removing said original article leaving a formed mould;
(c) introducing a charge of water-containing material into the formed mould; (d) exposing said mould and the material therein to a reduced temperature at least partially to freeze the material;
(e) removing said material from said mould whilst still at least partially frozen, and
(f) causing or allowing said material to harden or set and shrink after removal from said mould thereby to form a reduced size copy of said original article.
15. A method according to Claim 12, further including the step of causing or allowing removal of an amount of water from said charge in said mould before said mould is exposed to said reduced temperature.
16. An article whenever produced in accordance with any of the preceding Claims.
PCT/GB1992/001674 1991-09-14 1992-09-11 Method of casting and reproduction and an article produced by this method WO1993005940A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP5505878A JPH06510712A (en) 1991-09-14 1992-09-11 Casting and reproduction methods and articles produced by this method
EP92919453A EP0603277A1 (en) 1991-09-14 1992-09-11 Method of casting and reproduction and an article produced by this method

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB919119696A GB9119696D0 (en) 1991-09-14 1991-09-14 Methods of casting and reproduction
GB9119696.4 1991-09-14

Publications (1)

Publication Number Publication Date
WO1993005940A1 true WO1993005940A1 (en) 1993-04-01

Family

ID=10701441

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1992/001674 WO1993005940A1 (en) 1991-09-14 1992-09-11 Method of casting and reproduction and an article produced by this method

Country Status (5)

Country Link
EP (1) EP0603277A1 (en)
JP (1) JPH06510712A (en)
AU (1) AU2560892A (en)
GB (1) GB9119696D0 (en)
WO (1) WO1993005940A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19612386A1 (en) * 1995-03-29 1996-10-02 Ngk Insulators Ltd Freeze moulding process for prodn. of ceramic mouldings
RU2716677C1 (en) * 2018-12-03 2020-03-13 Федеральное государственное бюджетное образовательное учреждение высшего образования Санкт-Петербургская государственная академия ветеринарной медицины ФГБОУ ВО СПбГАВМ Method for making anatomical copies of bones by casting in silicone mould

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE258921C (en) *
CH497956A (en) * 1968-09-14 1970-10-31 Schimmel Stay Annemarie Mould for casting artificial stone
US3732048A (en) * 1970-02-18 1973-05-08 Int Standard Electric Corp Apparatus for casting of ceramics
DE2361304A1 (en) * 1973-01-30 1974-08-01 Kahla Veb Porzellan Moulded ceramic article prodn - by freezing slip in undercooled mould, demoulding, and dehydrating
GB2118475A (en) * 1982-04-08 1983-11-02 Norton Co Slip-casting method
GB2232115A (en) * 1989-05-31 1990-12-05 Hoechst Ag Ceramic castings

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE258921C (en) *
CH497956A (en) * 1968-09-14 1970-10-31 Schimmel Stay Annemarie Mould for casting artificial stone
US3732048A (en) * 1970-02-18 1973-05-08 Int Standard Electric Corp Apparatus for casting of ceramics
DE2361304A1 (en) * 1973-01-30 1974-08-01 Kahla Veb Porzellan Moulded ceramic article prodn - by freezing slip in undercooled mould, demoulding, and dehydrating
GB2118475A (en) * 1982-04-08 1983-11-02 Norton Co Slip-casting method
GB2232115A (en) * 1989-05-31 1990-12-05 Hoechst Ag Ceramic castings

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19612386A1 (en) * 1995-03-29 1996-10-02 Ngk Insulators Ltd Freeze moulding process for prodn. of ceramic mouldings
US5861115A (en) * 1995-03-29 1999-01-19 Ngk Insulators, Ltd. Method for freeze molding
RU2716677C1 (en) * 2018-12-03 2020-03-13 Федеральное государственное бюджетное образовательное учреждение высшего образования Санкт-Петербургская государственная академия ветеринарной медицины ФГБОУ ВО СПбГАВМ Method for making anatomical copies of bones by casting in silicone mould

Also Published As

Publication number Publication date
AU2560892A (en) 1993-04-27
EP0603277A1 (en) 1994-06-29
GB9119696D0 (en) 1991-10-30
JPH06510712A (en) 1994-12-01

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