US2669762A - Method for making ware by casting - Google Patents

Method for making ware by casting Download PDF

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US2669762A
US2669762A US335292A US33529253A US2669762A US 2669762 A US2669762 A US 2669762A US 335292 A US335292 A US 335292A US 33529253 A US33529253 A US 33529253A US 2669762 A US2669762 A US 2669762A
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mold
casting
ware
conduit
pressure
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Andrew R Blackburn
Richard E Steele
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    • 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
    • B28B1/261—Moulds therefor

Definitions

  • Solid casting regardless of whether the slip is forced into a cavity by gravity only or injected into a cavity by elevated pressures, above that of the gravity feed is generally conducted at present along the following lines.
  • the slip or fluid casting preparation is introduced or injected into an object forming cavity of the mold.
  • the mold usually consists of two or more sections and is made from one of the suitable gypsum plasters or other suitable mold material.
  • the slip which may be prepared from a variety of ceramic raw materials, and well known to the art, is characterized by a higher specific gravity than that type required for ordinary draincasting and may in the case of pressure casting have a livery consistency. In pressure feed casting there is no need for the slip to flow freely.
  • the charge After introduction of a slip, the charge must remain in contact with the entire object forming cavity of the mold until, by the process of absorption of the water from the slip by the mold or by forcing the water into the mold as a result of extreme slip pressures, the charge within takes on the character of a solid throughout, at which time the formed charge commences to undergo normal shrinkage. If at this time there is any tendency in the formed charge orfobject to contract and bind upon any of a plurality of mold sections, such as the core portion of a mold forming the interior of an object, such a section may be removed manually, by exercising extreme care, from contact with the object. Such mold sections have been withdrawn from the formed object by pressurizing, a section bymeans of a conduit extending into the mold section. When such a type of mold section withdrawal is practiced, the object is backed up by other supporting mold sections and the entire mold is in the closed position when pressurized.
  • Mold sections are also sometimes removed so that the exposed were with its supporting mold members may be subjected to a drying treatment to hasten the final shrinkage release of the formed object. Although it is possible to remove special sections of the mold soon after solidification, the object for a time remains in an easily deformable condition and adheres to the remaining mold members until finally released by the shrinkage inherent in-the object.
  • the molds are usua1ly Worked in the proximity 3 of a drying means so as to keep the molds in a workable condition.
  • Dry molds are most imperative for gravity casting which depends largely upon the absorption properties of the plaster and where at best production may not exceed 6 pieces per mold per day, and may be no greater than 1 piece per day. Although it is true that dry molds are not as necessary for pressure casting; -the waterw being forcedinto the mold under pressurecarries small colloidal particles and other harmful soluble materials into the pores and soon blocks them'to further use.
  • the present invention has for an object the provision of a novel method' and' means' 'ror the manufacture of ceramic ware, wherein the above mentioned disadvantages are obviated.
  • a further object is to provide a novel method and apparatus for forming ceramic objectswhich may be employed in combination with present :manufactnre'enethodsi to .increasesmarkedlyl the -rprodution rate advantageous for rcembination -wu'th,.;-processes :-..
  • the invention 1 articularly which are unsuccessful due to. limitationinhandlinge certain types of mcldable materiaiss such erasare used-incasting, whichiwhen handled often result 2 in unsatisfactory objecta'elease from the :mold, l. causing! the obj ect to warp er :crack.
  • :A further: object .iswto;.provide-a:novel method wand aapparatusfor f or-ming ware-of l. irregular shape or; thickness "whereinthe effect of. differen- ,tial shrmkage-on separation .ofla formed obiect .from the :rnold, iseliminated and. the number: of -;molds necessary for. accomplishing. arcont-in-uous 101318617 forming: operation-is minimized.
  • nn additionaland related-iobgect- resides.inthe iinitial reduction -.of pressures within molds-secs 5 to the cleansing of the pores of the mold, following casting, a desired purging action eliminating sealing of porous molding surfaces by adjacent colloidal particles, and other harmful soluble impurities.
  • Anot'hcr object of the invention is to provide a means for increasing ceramic mold life by the --continual reduction of saturation of a mold or moldsduringuse avoiding reliance upon expensive dr 'ing equipment.
  • 'i Figure 1 is a vertical section of the mold of the present invention; with the male and female :mold sectionabrought "together .inwclampin eneasement;
  • Fg-igiure "3 is -.a-perspecti-veview -,of a mortiomof .cliuid pressure. conduiteemployed in :,forming .the
  • Figure 4. is avertical :section ,ofathetinvention wherein multiple casting: sections in-iexcessofa-two are employed;
  • Figure-5 is a partiaLtopplan-yiew oflthemodification. shownin r Figure. 4 taken. alongr-the line 5-5 of Figure 4.
  • the. :inventionscomprises (a. novel..me.thodand;.means of :separating -ceramic. objectsfrommold surfaces. by-theapplication of. fluid .pressure uniformly-against .the .faceof the formedobjectdesired torbe separated ..controlling the .pressureiin .selected areasdrnac- .cordance with ..the. requirements .of .obi ect .thickinesstand ,shape. JIYhe. sourceof ,pressure .is,.-pr.ef-
  • the invention may be emialoyedsatiSfabtorily with .known forming ,processessuch, as ...casti ng under varying conditions wherein. ,thecaSting materials are tempered with water orOther mediums and which normally .employ shrinkage release of the object from v.the.mold. .jSucn. old
  • the numeral It refers generally to a mold constructed in accordance with the invention, including a top or female mold section l2 and a bottom male mold section l4. Each mold section is formed in a casing l6,
  • the casings are perforated as at I8 to facilitate purging in the manufacture of the mold body and to eliminate the development of interfering back pressures in the passage of fluid pressure through the mold for the release of ware and cleansing of the molding face of the mold body.
  • the casings I l 6 are sealed to retain pressure and liquid seepage during a casting operation.
  • the bodies l2 and I4 of the apparatus are formed of a material capable of hardening upon standing to form a solid porous and permeable element characterized by an ability to absorb moisture.
  • a high grade of gypsum plaster or other suitable hydraulic setting cements may be employed. It is preferred to use a hard gypsum cement rather than soft plaster in view of itsiex- I treme hardness. longs the life of the mold.
  • the plaster body Such a cement markedly pro- I molding faces and 22 by impression with suit- I able forms prior to hardening of the mold material.
  • A. cavity 24 is formed by the opposed molding faces 20 and 22, the cavity beingsealed as at 26, where complementary surfaces of the respective mold. bodies engage.
  • Mold section 12 forms channel 28 which passes from the exterior of the casing H3 inwardly to the molding face 22. This channel 28 employed to introduce slip under pressure into cavity 24.
  • the channel walls 30 may be impregnated with suitable sealers to render them impervious to slip and to fluids.
  • a conduit 32 is threaded into the cylindrical wall 30 of channel 28 providing valved passage forthe" slip from a pressurized reservoir 36.
  • the flow control valve is designated as at 34.
  • Slip maybe introduced to the reservoir through an inlet conduit 38.
  • the reservoir is pressurized by means not shown.
  • Clamping means 42 are attached to the exterior of the casings It to secure the mold'bodies-to- 5 gether.
  • the clamping means maybe a conventiona'l butterfly nut-clamp arrangement.
  • fluid pressure means are formed in the plaster bodies l2 and I4 for effecting removal of a clay object 40 from either or both of the mold faces 2
  • Said means include a conduit 44 having an extension 46 passing through the casing of the mold body to a source of fluid pressure, not shown.
  • the conduit 44 may preferably comprise a tubular member formed of an easily workable material which is corrosion resistant, such as a metal.
  • the conduit 44 may be supported against radial displacement by one or more bracket members opening into the body of the plaster molds.
  • the bracket 45 is formed to engage with any section of the conduit in order primarily to secure the conduit 44 firmly during formation and as the plaster mold hardens.
  • the plaster casts l2 and I4 may be locked in the mold by dimpling the casings I6 as at different portions thereof 19, thereby preventing accidental displacement of the plaster casts in or from the molds upon the application of fluid pressures to the conduit 44.
  • the conduit 44 is apertured as at 48 along its length, the apertures
  • the apertures 48 are formed to provide a plurality of streams of fluid pressure in such a manner to provide an evenly dispersed blanket of pressure across the face of the clay object adjacent the mold surfaces 20 and 22.
  • the conduit 44 is preshaped to provide evenly spaced sources of fluid pressure about the entire face of the object 40.
  • the conduit 44 in one configuration preferably is formed as a helix, with the coils thereof positioned internally of a mold section away from the face of the mold section but generally parallel to the contour of the clay object 40. In some instances, the conduit will be wound concentrically about itself as shown at the top of the mold body 12.
  • the spacing and size of the pressure apertures 48 and the distance between a section of the conduit 44 and the adjacent face of the clay object 40 and the spacing between related portions of the conduit destermine the amount of fluid pressure which will be exerted on a portion of the clay object.
  • the conduit 44 As shown in Figure 3, it is preferred to enclose the conduit 44 with wrapping of permeable fab- .ric material such as gauze 5!
  • the gauze serves to maintain the apertures 48 free from obstruction through. the accumulation of particles of plaster, and provides a pressure chamber between I the plaster and the conduit 44.
  • Such a. chamber facilitates building up of a fluid pressure head outside the conduit M in the body of the porous plaster mold in the direction of the mold face,
  • .A.-moldwgenera1ly o'mdicated as-at iii: comprises. mold-1 sections-6.2;. ...-a.nd- 6.6. .xcasing .53 which maybe oonstructedof. any-corrosion-resistant: .rnaterial. fIfh-e 'casingsemay; .be ..;pe1'forated or not :depending upon .th ..-type of castingidesired.
  • the,. --principle. of the vinvention :rmayedoe employedain the manufacture .hf ware ...from .a variety of.-.casting..materials.
  • a preferred type of 'sliplusedina.pressuracastring operation is rnormallyiof .greatefldensityi-than athatcmployed :in gravity castings. Accordingly, iand-inkeeping with current practice hereunder,
  • -'.a .1ivery .slip. maywbenforced .under .pressure .throughthe conduit and .intoothe .cavityliormed ,-by the. opposed-..mo1ding Ffaces. hi the anold .sec- -tions. :Atthis .time,.-.the.mold sections. may; be evacuated .-by.-.means-..ofc the. conduits within to .render the -mold -sections. morev .absorptive".fthus .accelerating .the setting action o'fi;the.slip,'lthe .aslip-being.underpositivepressure w'ithin'the .cav-
  • NAT study .of..the-structure. of .the invention...w.ill disclose that .a .vacuum..-may..be "created .in either .one .ot-thdmolding units .to the exclusion-of .the other. and that ffluidpressures may be ap'plid toeither surfaceofa cast obj.ect,..dependent.upon .lthe... qualities thereof desired.
  • Various adapta- "tions in structure and operation though. not. spe- ..cifica l1y -described .herein may. vbe..made without departing-tram the spirit. of ..the invention.
  • a method for casting green ceramic ware in a porous mold and for separating the cast ware completely from the mold after the ware has become self-sustaining and, independently of the shrinkage of the ware, to promptly free the mold for reuse which comprises causing a slip to fill a ware-forming cavity defined by a plurality of permeable mold members, maintaining said slip in said cavity in contact with said mold members for a time sufiicient to render said slip selfsustaining and form an easily deformable green piece of ware, thereafter before said piece shrinks appreciably (a) passing a fluid under pressure through a first of said mold parts to release said piece therefrom and (b) separating said first mold part from said piece to leave said piece supported only by the remaining mold parts and (c) thereafter passing a fluid under pressure through said remaining mold parts to separate the unsupported piece completely therefrom and free the mold for reuse in the formation of additional pieces of Ware.

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

Description

Feb. 23, 1954 A. R. BLACKBURN ET AL METHOD FOR MAKING WARE BY CASTING Filed Feb. 5, 1953 FIG. I.
3 Sheets-Sheet 1 INVENTOR ANDREW RLBLAOKBURN RICHARD E. STEELE M VJW ATTORNEYS 1954 A. R. BLACKBURN ET AL I ,669,7
METHOD FOR MAKING WARE BY CASTING Filed Feb. 5, 1953 3 Sheets-Sheet 2 INVENTOR ANDRE R. BLACKBURN RICH D E. STEELE ATTORNEYS 1954 A. R. BLACKBURN ET AL 2,669,762
METHOD FDR MAKING WARE BY CASTING Filed Feb. 5, 1955 5 Sheets-Sheet s INVENTOR NDREW R. BLACKBURN RiCHARD E. STEELE ATTORNEYS Patented Feb. 23, 1954 UNITED STATES;
RATENT OFFICE Andrew R. Blackburn and Richard E. Steel Columbus, Ohio Application February 5, 1953, Serial No. 335,292
1 Claim. 1
stant application for patent.
In both solid casting methods as presently employed the formed object is separated finally from the mold by the shrinkage action inherent in the object upon losing a portion of its water of plasticity. However certain mold sections can be removed from contact with the ware before the ware shrinkage has progressed to any appreciable degree, in order to prevent contraction of the object about the mold section and without damaging the easily deformed object as long as the object is sufficiently supported by the remaining mold parts. istics and water retentive properties of the different slip or casting preparations vary considerably. This factor, in addition to the reconditioning period required for a mold to free itself of its held water and thus restore its absorption properties has prevented the rapid production of ceramic ware from a one mold unit and it has been necessary to employ large numbers of molds in an object forming operation in order to over come to some extent the delay inherent in shrinkage release of objects from molds.
It follows that multiple porous molds have been employed to accelerate water absorption from a'slip. Shrinkage of the formed object thus becomes a function of the porosity of the mold and the water retention capabilities of the cast object. While the production rate is thus accelerated, the presence of the two variable factors effecting shrinkage contribute to a lack of uniformity in the end product.
This is especially the case with the molding of objects having different thickness measurements in which the overall shrinkage rate is impossible to anticipate, except by tedious experiment with different types of casting materials and repeated object casting until a perfect object is produced. Generally, irregular shrinkage results me high percentage of breakage during and subsequent to removing the object from 1 the mold faces, and shattering during the finish- The shrinkage character- 2, ing operations from stresses developed in the ware structure. This is particularly the case with ware having, for example, a thin base and thickened sides, or vice versa.
Solid casting regardless of whether the slip is forced into a cavity by gravity only or injected into a cavity by elevated pressures, above that of the gravity feed is generally conducted at present along the following lines. The slip or fluid casting preparation is introduced or injected into an object forming cavity of the mold. The mold usually consists of two or more sections and is made from one of the suitable gypsum plasters or other suitable mold material. The slip which may be prepared from a variety of ceramic raw materials, and well known to the art, is characterized by a higher specific gravity than that type required for ordinary draincasting and may in the case of pressure casting have a livery consistency. In pressure feed casting there is no need for the slip to flow freely.
After introduction of a slip, the charge must remain in contact with the entire object forming cavity of the mold until, by the process of absorption of the water from the slip by the mold or by forcing the water into the mold as a result of extreme slip pressures, the charge within takes on the character of a solid throughout, at which time the formed charge commences to undergo normal shrinkage. If at this time there is any tendency in the formed charge orfobject to contract and bind upon any of a plurality of mold sections, such as the core portion of a mold forming the interior of an object, such a section may be removed manually, by exercising extreme care, from contact with the object. Such mold sections have been withdrawn from the formed object by pressurizing, a section bymeans of a conduit extending into the mold section. When such a type of mold section withdrawal is practiced, the object is backed up by other supporting mold sections and the entire mold is in the closed position when pressurized.
Mold sections are also sometimes removed so that the exposed were with its supporting mold members may be subjected to a drying treatment to hasten the final shrinkage release of the formed object. Although it is possible to remove special sections of the mold soon after solidification, the object for a time remains in an easily deformable condition and adheres to the remaining mold members until finally released by the shrinkage inherent in-the object.
The molds are usua1ly Worked in the proximity 3 of a drying means so as to keep the molds in a workable condition.
Dry molds are most imperative for gravity casting which depends largely upon the absorption properties of the plaster and where at best production may not exceed 6 pieces per mold per day, and may be no greater than 1 piece per day. Although it is true that dry molds are not as necessary for pressure casting; -the waterw being forcedinto the mold under pressurecarries small colloidal particles and other harmful soluble materials into the pores and soon blocks them'to further use.
The present invention has for an object the provision of a novel method' and' means' 'ror the manufacture of ceramic ware, wherein the above mentioned disadvantages are obviated.
A further object is to provide a novel method and apparatus for forming ceramic objectswhich may be employed in combination with present :manufactnre'enethodsi to .increasesmarkedlyl the -rprodution rate advantageous for rcembination -wu'th,.;-processes :-..The invention 1 articularly which are unsuccessful due to. limitationinhandlinge certain types of mcldable materiaiss such erasare used-incasting, whichiwhen handled often result 2 in unsatisfactory objecta'elease from the :mold, l. causing! the obj ect to warp er :crack.
:-.-Apfurther. obj ectdsnto provide novel; method sand; apparatus zfort thetnmanufacture refiners-mic ifurthelx object is to i provide methodna-nd a apparatus; for the manufacture of ceramic ware 'wWhGIGlIL through :quiclc-releasetofsthe object from the ."mo1d,1ahigh speed ;.prodnction rate attained; without:sacrificingsthe quality: of. product 1 and withimarked reduction" of -..-unit; cost.
A fUI'thQFzGbjQCt'rlSitOlEI'OVidfi-Q; method and apparatus for forming "-twarewherein adherence of .the formed. object :to rthe .mold trace or faces cant .be controlled by- :the.v operator, u'irrespective ,of.-. shrinkage characteristics or ldensitycof. .tlie
. molded object.
:A further: object .iswto;.provide-a:novel method wand aapparatusfor f or-ming ware-of l. irregular shape or; thickness "whereinthe effect of. differen- ,tial shrmkage-on separation .ofla formed obiect .from the :rnold, iseliminated and. the number: of -;molds necessary for. accomplishing. arcont-in-uous 101318617 forming: operation-is minimized.
;. A.further. object .is. to-providea .novelimethod forleffectingthe quick release of. ceramic objects from. -mold surfaces,- without. iniuring the .zware, before. normal. shrinkagei..occurs.
A further .objectis to provide.a nove1.m,ethod and apparatus. for the manufacture; of asymetri- "cally shaped clay objects. Still a further objectistogprovide. a novel-mold *for use-in-casting ceramic'objectswhich is .in'ex- -penSiVelyand' easily fabricated;'permittingpf frequent design changes;an'davliich-is'adapt'able for :use 'with presently employed "casting processes andzapparatus- .;:An :addition'al object resides in I the provision .;of :means: and cmethod :foryacuum removalof e-absorbed? fluids 'from mold tsectionsrssuch as are expressed. from tlrermolded obj ectt into ther'ni'old sectionsnand subsequently :purging memaining flu-ids. not previously *.evacuated from "the zmold sections.
nn additionaland related-iobgect-;resides.inthe iinitial reduction -.of pressures within molds-secs 5 to the cleansing of the pores of the mold, following casting, a desired purging action eliminating sealing of porous molding surfaces by adjacent colloidal particles, and other harmful soluble impurities.
Anot'hcr object of the invention is to provide a means for increasing ceramic mold life by the --continual reduction of saturation of a mold or moldsduringuse avoiding reliance upon expensive dr 'ing equipment.
1.;. Others'objects and advantages of the present invention will be found in the following detailed ..descr iption-.thereof and the accompanying drawings, wherein:
'iFigure 1 is a vertical section of the mold of the present invention; with the male and female :mold sectionabrought "together .inwclampin eneasement;
. Figureszsisea partial top-plan (view of;- the':.fecmalenmoldttaken along the line 2-:-2.-of Eigureil;
Fg-igiure "3 is -.a-perspecti-veview -,of a mortiomof .cliuid pressure. conduiteemployed in :,forming .the
mold.
.Figure 4. is avertical :section ,ofathetinvention wherein multiple casting: sections in-iexcessofa-two are employed;
Figure-5 is a partiaLtopplan-yiew oflthemodification. shownin r Figure. 4 taken. alongr-the line 5-5 of Figure 4.
Initsv broadest application, ,the. :inventionscomprises (a. novel..me.thodand;.means of :separating -ceramic. objectsfrommold surfaces. by-theapplication of. fluid .pressure uniformly-against .the .faceof the formedobjectdesired torbe=separated ..controlling the .pressureiin .selected areasdrnac- .cordance with ..the. requirements .of .obi ect .thickinesstand ,shape. JIYhe. sourceof ,pressure .is,.-pr.ef-
.erably sodisposed.inurelation to..the contourand .anyselected .areanofsthe. object as-.to ..provide a predictable, controlled .force .in thefiform .of. a pressure blanket exerted simultaneously..across the .entire .surface.area..of.-the.cenamiclobject,iin
accordance with. a.pre:s'electedpressuretpattern, whereby releaseof.theobjectjrom themoldsurface is accomplished without .-imparting..-.nnclue shock or straintoltheobjectonany part thereof.
'The inventionmay be emialoyedsatiSfabtorily with .known forming ,processessuch, as ...casti ng under varying conditions wherein. ,thecaSting materials are tempered with water orOther mediums and which normally .employ shrinkage release of the object from v.the.mold. .jSucn. old
processes are characterized .byextremely.;.slow rate of .production, due to thainabilityto release the. ware :from .the .casting...m'olds .are...normal shrinkage 'which occurs ."by i the Telapsel .oft1time. "However, the .invention 'is "most advantageously employed with "formin'gprocesses" wherein .uniform shrinkage r'elease-ofthe objectv from "the =mold is difiicult or impossible. The invention permits of employing mass production methods without a, great need'forimany duplicate molds. An ordinary casting operation thatiformerly took :hours' for a singleobject now'for .the.;first..time can be accomplished in minutes. ..J.Eor..instance,
" the. art of. pressure casting had practical1y,.be-
come obscure ..until thepresent invention. .lNow,
.however,.-longy. mold life, clear post-casting 1 mold zsurfacesaare made readily available andzthere is .IaireviYal. .of-a valuable art.
,1 7s hea invention; may .be ;employed 'zwithu'gravity aeca'zea solid casting, drain casting, and external pressure solid casting where the slip used is of a higher specific gravity than normally employed in gravity casting. For purposes of illustration, invention will be described as employed in ex' ternal pressure and gravity pressure casting, the 1 other methods and devices for carrying out related processes having been described in our United States Patent No. 2,58%,109 entitled Method and Y Apparatus for Making Ware, issued February 5, j 1952. It will be readily apparent, however, that the principles of the invention may be applied equally well to other methods of forming ceramic ware.
Referring to the drawings, the numeral It refers generally to a mold constructed in accordance with the invention, including a top or female mold section l2 and a bottom male mold section l4. Each mold section is formed in a casing l6,
:' which may be constructed of any corrosion resistant material such as alloy steel, which may be assembled by welding. In one form of the invention the casings are perforated as at I8 to facilitate purging in the manufacture of the mold body and to eliminate the development of interfering back pressures in the passage of fluid pressure through the mold for the release of ware and cleansing of the molding face of the mold body.
In another form of the invention, the casings I l 6 are sealed to retain pressure and liquid seepage during a casting operation.
The bodies l2 and I4 of the apparatus are formed of a material capable of hardening upon standing to form a solid porous and permeable element characterized by an ability to absorb moisture. A high grade of gypsum plaster or other suitable hydraulic setting cements may be employed. It is preferred to use a hard gypsum cement rather than soft plaster in view of itsiex- I treme hardness. longs the life of the mold. The plaster body Such a cement markedly pro- I molding faces and 22 by impression with suit- I able forms prior to hardening of the mold material.
A. cavity 24 is formed by the opposed molding faces 20 and 22, the cavity beingsealed as at 26, where complementary surfaces of the respective mold. bodies engage.
Mold section 12 forms channel 28 which passes from the exterior of the casing H3 inwardly to the molding face 22. This channel 28 employed to introduce slip under pressure into cavity 24.
The channel walls 30 may be impregnated with suitable sealers to render them impervious to slip and to fluids. A conduit 32 is threaded into the cylindrical wall 30 of channel 28 providing valved passage forthe" slip from a pressurized reservoir 36. The flow control valve is designated as at 34. Slip maybe introduced to the reservoir through an inlet conduit 38. The reservoir is pressurized by means not shown. l
Clamping means 42 are attached to the exterior of the casings It to secure the mold'bodies-to- 5 gether. The clamping means maybe a conventiona'l butterfly nut-clamp arrangement. In accordance with the present invention, fluid pressure means are formed in the plaster bodies l2 and I4 for effecting removal of a clay object 40 from either or both of the mold faces 2|] and 22, preferably prior to shrinkage normally occurring upon losing a portion of water of plasticity of the clay. Said means include a conduit 44 having an extension 46 passing through the casing of the mold body to a source of fluid pressure, not shown. The conduit 44 may preferably comprise a tubular member formed of an easily workable material which is corrosion resistant, such as a metal.
- The conduit 44 may be supported against radial displacement by one or more bracket members opening into the body of the plaster molds.
45. The bracket 45 is formed to engage with any section of the conduit in order primarily to secure the conduit 44 firmly during formation and as the plaster mold hardens. The plaster casts l2 and I4 may be locked in the mold by dimpling the casings I6 as at different portions thereof 19, thereby preventing accidental displacement of the plaster casts in or from the molds upon the application of fluid pressures to the conduit 44.
Referring to Figures 2 and 3, the conduit 44 is apertured as at 48 along its length, the apertures The apertures 48 are formed to provide a plurality of streams of fluid pressure in such a manner to provide an evenly dispersed blanket of pressure across the face of the clay object adjacent the mold surfaces 20 and 22. The conduit 44 is preshaped to provide evenly spaced sources of fluid pressure about the entire face of the object 40. To accomplish this, the conduit 44 in one configuration, preferably is formed as a helix, with the coils thereof positioned internally of a mold section away from the face of the mold section but generally parallel to the contour of the clay object 40. In some instances, the conduit will be wound concentrically about itself as shown at the top of the mold body 12.
The spacing and size of the pressure apertures 48 and the distance between a section of the conduit 44 and the adjacent face of the clay object 40 and the spacing between related portions of the conduit destermine the amount of fluid pressure which will be exerted on a portion of the clay object. By adjusting these variables, a controlled adherence of the clay object to the mold surfaces is accomplished. The operator may obtain adherence of any portion of the ware to any desired part of the mold for a. preferred length of time, by exercise of this available control of the were I releasing pressure. Thus, regardless of the relative or differential thicknesses of the several parts of the ware, as for example the beaker shown in Figure 1, a fully controlled quick release of the object from the mold may be accomplished, without danger of injury to the ware from the ever present tendency to crack at the thin], points, upon the application of pressures thereto. It will be appreciated that full release is not attempted herein with such time as the setting may have i been, eifected and until the clamps have been loosened sufiiciently to allow free release action.
As shown in Figure 3, it is preferred to enclose the conduit 44 with wrapping of permeable fab- .ric material such as gauze 5! The gauze serves to maintain the apertures 48 free from obstruction through. the accumulation of particles of plaster, and provides a pressure chamber between I the plaster and the conduit 44. Such a. chamber facilitates building up of a fluid pressure head outside the conduit M in the body of the porous plaster mold in the direction of the mold face,
' accelerating the passage of the fluid pressure .aza cecma 'ct'hrough zthe -body. -of=. thermold. .a-FIlhe-rconduite :un'ayibe plugged tocform: a-..-dead.*.end-.1'n ithe-mold 'Jibddfy. :QtherEform oficonduitszmaywbesemployed ...includingforaminous. tubing of suiiiciently rig-id- .-iityito be selfsupporting. I
' rhemmethod 0f. manufacture of ia ipreferred tmold body-and thestructure ithereof iisrmore-iully disclosed and. claimed rinour United States Pat- -e1-1t:.-No. -2-;584,i-1O entitled --Mold andMethodzof i :Manuf-acture i-ssuedi Februaryb, 1952. -:-It-is 'pointa cd=out therein \that-aconduit-such as Mrmay also I abet-formed. advantageously .by casting witmwax or .-aelowzmeitingv point =meta1 alloy. zincludingi a bismuth.;alloy,. removable by."subjecti ng.-.th'e mold to---e1evatedtemperatures as-'soon.-asthe plaster lhardens.
.Aimo-diiication- :of the invention-iszshowrrinaFi llles'rll and 5 of. the drawings. .A.-moldwgenera1ly o'mdicated as-at iii: comprises. mold-1 sections-6.2;. ...-a.nd- 6.6. .xcasing .53 which maybe oonstructedof. any-corrosion-resistant: .rnaterial. fIfh-e 'casingsemay; .be ..;pe1'forated or not :depending upon .th ..-type of castingidesired.
erably disposed with molding .-face 12 01. rmlold .iisection -fili. In thisparticular modification,..mold --section E6 engages receivingsurfaces of. moldvsec- =.tions-.62- and15 i, the Tmold .section -66 forming a imale molding-surface as atfhi. Themolding-surfaces 10,--'l2and 14..together form a-cavityJB @suitable. for receiving..s1ip either. undercpressure .or-.by-. g1'.a vity feed as shown. In.:the..drawings .sshowmv-themold Bil is compietely assembledfor casting the cavity IScontainingby way of. illus- .-.-tration, zalslip 1 ill] which has -been .introduccdby gravity feed.
:In the modificationin Figures. 4 and5;;a-funnel ,portion 78. .leading' into. a. :channe1..B0. .has .been
formed in the mold sectionsfiZ-and 54 respectivesubstantially as hereinbeforeldescribed. .In the mold bodies Hand 64 respectivlelmthe conduit 7 passes ai'cuatelyback .and forth across'ltheseniicircular section thereof, the conduit beingIspaiced fat' distances critical from the.mblding"face .lllbf "I'th'e.mo'1d body. As hasbeenprevioushl explained, 31'fihe1proxiniity o'f'the conduitmembertoithe. mold- ."inglface of the mold i dependent upon the pordsitydesired in the end mold product. and the *"d'esiredn'eleasepressures to be uniformlyobtainedat the mold face. that the conduit will be disposed more'prox'imate "thewnold face at portions adjacentheavier portions 'ofthe 'ware and mor distantat portions adjacentthinner portions of theware. However, the conduit may be placed equidistant'from the molding face or otherwise disposed to e'fiect uni- Iform release. :Mold section 6 4 contains. a conduit .JBA'LsubstantialIy similar to that....defined,.for..the zmoidbodyfil .In the-mold section .66l.the -.conduit M84 .is likewise strategically displaced---within-.the
. Eachwmold sectioneis;,-provided =with=ia- It may be apparent ;mo-ld":seotion-rdistantifromathe 2mo1dmg -iac t1l thereof. =.;In rthis-.instanceihowever,.itaisipreferred :iithat uthe conduitwmember :be secured .helically aboutvthesinterior oftthe \mold seotioniandlcriti- -cally distant :adjacent the. molding surface J4. -.'Ihe ;;pressure apertures I are indicated. as tats.
'- .-l'.likewise the disposition 1 of-the .oonduit 'through szmold bodies 6 2 and-=64 respectively isiindicatedias -at QO-inFigure'S.
:01:18 ior'more bracket members a 92 protrude k inwardly :from the casing1B8aof-each ofsthe respec- -tivemo1d sections to;provide:supporttothetubing s-structure -within'-.the-.mold during tthedformation thereof. In addition there are provided recesses 1: 94 fstrategicallyiabout ithe .interior ofsthe casing 68. to-secure the.-mo1d.. against movementwithin 1 thecasing member.
operation, the,. --principle. of the vinvention :rmayedoe employedain the manufacture .hf ware ...from .a variety of.-.casting..materials. As separation from-uthe...mo1d :is accomplished priornto .shrinkagereleasaof. the clayobject, rthe .unpre- ;dictable results.obtaining.from-theadifferinghcontraction propertie of. differenttypesof claysare eliminated as aproductioniactor. Accordingly. -.the invention. maybe .used tospeed. up .alLknown casting-methods of ware manufao-ture, .Whichnor .=mally require an hour onmoreior'adequateohiect shrinkage to. occur before -thenlay. lobje'ct separatesfromthemold.
A preferred type of 'sliplusedina.pressuracastring operation is rnormallyiof .greatefldensityi-than athatcmployed :in gravity castings. Accordingly, iand-inkeeping with current practice hereunder,
-'.a .1ivery .slip. maywbenforced .under .pressure .throughthe conduit and .intoothe .cavityliormed ,-by the. opposed-..mo1ding Ffaces. hi the anold .sec- -tions. :Atthis .time,.-.the.mold sections. may; be evacuated .-by.-.means-..ofc the. conduits within to .render the -mold -sections. morev .absorptive".fthus .accelerating .the setting action o'fi;the.slip,'lthe .aslip-being.underpositivepressure w'ithin'the .cav-
.iity. iormed by. the. respective...mold.ifaces. T he ..slipremainsincontact with the .mold cavity until Lthencharge .within .assumes fthecharacter .or a
:solid throughout [at which-Ltime. .it. commences toundergo normal shrinkage.
l Nowaiterwehavecast aovareobject, weseek ,ito removeimoldsections'irom.the were, in. DIED- aration for the final release ofthe ware,'by.means .,-.of..passing..fiuid pressure throughat .least. "one of the .mold. -sections. therebvlleaving lthe .lformed ware'upon another. supporting mold section. ".The -..o1iowing.-step mustbe undertaken'to removelthe ,formed warelirom the waresupporting moldsec- .tion. ..The. supporting moldnow Lhas fluidpres- 1 sure; i passed .itherethrough .to .the .molding face ;thereof, against the .iormed Ware to release ,the wareifrom. the. supporting .mold.section.
It will .be. appreciated ..that. .-.the .foregoing. ppwerative-description maybe..employed..to..describe .itheeprocess as -,-app1iedto. gravity: casting. and
draincasting.
NAT study .of..the-structure. of .the invention...w.ill disclose that .a .vacuum..-may..be "created .in either .one .ot-thdmolding units .to the exclusion-of .the other. and that ffluidpressures may be ap'plid toeither surfaceofa cast obj.ect,..dependent.upon .lthe... qualities thereof desired. Various adapta- "tions in structure and operation though. not. spe- ..cifica l1y -described .herein may. vbe..made without departing-tram the spirit. of ..the invention.
Qlt will be observed .that ithepresent invention provides .novel imethodsandimeans .fonlforming :...clay..;objects. 'zRossible. specific muses include-the manufacture of dinner ware, art ware including sculpture, decorative tile, terra cotta, refractories, and electrical porcelains. The controlled adherence principle of the invention may be employed to advantage with all ware forming processes, allowing release of the ware from the mold sections at any point in the manufacturing operation subsequent to casting.
Other obvious adaptations of the invention will occur to one familiar with the art. The invention eomprehends the substitution of equivalents, Where possible, and is to be limited only as defined in the appended claim.
This application is a continuation in part of copending Blackburn and Steele application Serial No. 265,766 filed January 10, 1952, which was copending with Blackburn and Steele application Serial No. 737,544, now Patent No. 2,584,110, and Blackburn and Steele application Serial No. 737,174, now Patent No. 2,584,109.
We claim:
A method for casting green ceramic ware in a porous mold and for separating the cast ware completely from the mold after the ware has become self-sustaining and, independently of the shrinkage of the ware, to promptly free the mold for reuse, which comprises causing a slip to fill a ware-forming cavity defined by a plurality of permeable mold members, maintaining said slip in said cavity in contact with said mold members for a time sufiicient to render said slip selfsustaining and form an easily deformable green piece of ware, thereafter before said piece shrinks appreciably (a) passing a fluid under pressure through a first of said mold parts to release said piece therefrom and (b) separating said first mold part from said piece to leave said piece supported only by the remaining mold parts and (c) thereafter passing a fluid under pressure through said remaining mold parts to separate the unsupported piece completely therefrom and free the mold for reuse in the formation of additional pieces of Ware.
ANDREW R. BLACKBURN.
RICHARD E. STEELE.
References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,541,869 Sprenger June 16, 1925 1,784,373 Miller Dec. 9, 1930 2,026,624 Flower Jan. 7, 1936 2,273,016 Bower Feb. 17, 1942 2,584,109 Blackburn et al. Feb. 5, 1952 2,584,110 Blackburn et a1 Feb. 5, 1952
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Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2893102A (en) * 1954-01-07 1959-07-07 William A Maxwell Article fabrication from powders
US2964822A (en) * 1954-12-27 1960-12-20 Shenango China Inc Process for the manufacture of ceramic objects
DE1115174B (en) * 1954-12-27 1961-10-12 Shenango China Inc Slip casting process for the production of ceramic goods
US3156751A (en) * 1961-12-06 1964-11-10 Crane Co Mold for forming a ceramic article and method of making the mold
US3242571A (en) * 1964-07-30 1966-03-29 Western Foods Machinery Compan Machines for molding plastic products
US3286974A (en) * 1962-05-09 1966-11-22 Mc Graw Edison Co Ceramic mold
US3309732A (en) * 1963-10-11 1967-03-21 Thomas M Dodds Inc Apparatus for stripping articles from forms
DE1299546B (en) * 1967-01-13 1969-07-17 Dorst Keramikmaschb Inh Otto D Process for die casting ceramic objects
DE1683921A1 (en) * 1966-08-27 1971-03-04 Philips Nv Method and device for the manufacture of products made of ceramic material
US4359435A (en) * 1978-04-19 1982-11-16 Yamato Kogure Method for manufacturing plastic products
US4882111A (en) * 1985-08-06 1989-11-21 Inax Corporation Method for obtaining drain-cast hollow articles
US5069609A (en) * 1986-07-26 1991-12-03 Toto Ltd. Mold used in pressure casting ceramic articles
US5299624A (en) * 1992-08-06 1994-04-05 Kohler Co. Fluid assisted casting apparatus
US20080153688A1 (en) * 2006-12-21 2008-06-26 Manfred Borens Quartz glass body, method and casting mold for manufacturing same
US8524319B2 (en) 2011-11-18 2013-09-03 Memc Electronic Materials, Inc. Methods for producing crucibles with a reduced amount of bubbles
US8857214B2 (en) * 2011-11-18 2014-10-14 Sunedison Semiconductor Limited Methods for producing crucibles with a reduced amount of bubbles
FR3098434A1 (en) * 2019-07-11 2021-01-15 Safran Aircraft Engines Tooling for the injection of a loaded slip

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1541869A (en) * 1919-01-28 1925-06-16 Sprenger Richard Process for the production of ceramic ware
US1784373A (en) * 1927-01-19 1930-12-09 William J Miller Pottery mold and method of making the same
US2026624A (en) * 1934-10-16 1936-01-07 Wesley B Flower Manufacture of earthenware
US2273016A (en) * 1939-04-01 1942-02-17 Taylor Smith & Taylor Company Apparatus for feeding ceramic slip
US2584109A (en) * 1947-03-12 1952-02-05 Ram Inc Mold and method for molding ceramic ware
US2584110A (en) * 1947-03-27 1952-02-05 Ram Inc Mold for pottery ware

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1541869A (en) * 1919-01-28 1925-06-16 Sprenger Richard Process for the production of ceramic ware
US1784373A (en) * 1927-01-19 1930-12-09 William J Miller Pottery mold and method of making the same
US2026624A (en) * 1934-10-16 1936-01-07 Wesley B Flower Manufacture of earthenware
US2273016A (en) * 1939-04-01 1942-02-17 Taylor Smith & Taylor Company Apparatus for feeding ceramic slip
US2584109A (en) * 1947-03-12 1952-02-05 Ram Inc Mold and method for molding ceramic ware
US2584110A (en) * 1947-03-27 1952-02-05 Ram Inc Mold for pottery ware

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2893102A (en) * 1954-01-07 1959-07-07 William A Maxwell Article fabrication from powders
US2964822A (en) * 1954-12-27 1960-12-20 Shenango China Inc Process for the manufacture of ceramic objects
DE1115174B (en) * 1954-12-27 1961-10-12 Shenango China Inc Slip casting process for the production of ceramic goods
US3156751A (en) * 1961-12-06 1964-11-10 Crane Co Mold for forming a ceramic article and method of making the mold
US3286974A (en) * 1962-05-09 1966-11-22 Mc Graw Edison Co Ceramic mold
US3309732A (en) * 1963-10-11 1967-03-21 Thomas M Dodds Inc Apparatus for stripping articles from forms
US3242571A (en) * 1964-07-30 1966-03-29 Western Foods Machinery Compan Machines for molding plastic products
DE1683921A1 (en) * 1966-08-27 1971-03-04 Philips Nv Method and device for the manufacture of products made of ceramic material
DE1299546B (en) * 1967-01-13 1969-07-17 Dorst Keramikmaschb Inh Otto D Process for die casting ceramic objects
US4359435A (en) * 1978-04-19 1982-11-16 Yamato Kogure Method for manufacturing plastic products
US4882111A (en) * 1985-08-06 1989-11-21 Inax Corporation Method for obtaining drain-cast hollow articles
US5069609A (en) * 1986-07-26 1991-12-03 Toto Ltd. Mold used in pressure casting ceramic articles
US5299624A (en) * 1992-08-06 1994-04-05 Kohler Co. Fluid assisted casting apparatus
US20080153688A1 (en) * 2006-12-21 2008-06-26 Manfred Borens Quartz glass body, method and casting mold for manufacturing same
US8104309B2 (en) * 2006-12-21 2012-01-31 Schott Ag Method and casting mold for manufacturing a quartz glass body
US8524319B2 (en) 2011-11-18 2013-09-03 Memc Electronic Materials, Inc. Methods for producing crucibles with a reduced amount of bubbles
US8857214B2 (en) * 2011-11-18 2014-10-14 Sunedison Semiconductor Limited Methods for producing crucibles with a reduced amount of bubbles
FR3098434A1 (en) * 2019-07-11 2021-01-15 Safran Aircraft Engines Tooling for the injection of a loaded slip

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