CA2426515A1 - Process for preparing detailed foundry shapes and castings - Google Patents

Abstract

This invention relates to a process for preparing detailed foundry shapes (e.g. molds and cores) used in casting metal articles. The process involves preparing foundry shapes from hollow ceramic microspheres bonded with organic or inorganic binders. The foundry shape is then detailed by machining, cutting, stamping, or otherwise removing material from the foundry shape to provide special shapes, letters, numbers, insignia, machine readable codes, etc. on the surface of the foundry shape. The foundry shapes are used to produce detailed metal castings. This detail can be unique to a single casting to provide a permanent traceable mark for casting identification from the time of manufacture to disposal.

Description

1 ~".~?a~I~ES~ 1~'~' I1.D~Tl~~L~.~ ,~'~DTT~~~R~' ~~'~a~ ~T~~
CRO~~,REFEIZENCE TO R,.ELATEL~ AI~PLI~A'I~IC3~iS
s r Not Applicable.

CLAIIvi Tf~ 1SIE.T(~~ITY

1 o Not Applicable.

12 ~TATEI~1,EN'T' E.EG.A.R.DINCi FEDERALLY ~PON~OItEI~ I~E~EA1~.~EL C?1~.
13 DEVELt~FIVLENT

~ 5 Not Applicable.
1~
17 REFERENCE T~ A NxZ~It,CIFIIyHE API~ENI~IX

Not Applicable.
2p 2 t BAC~.I~t7UND t~F THE I~VENTIC~N

23 ~ I ) Field of the Invention ~5 This invention relates to a process for preparing detailed foundry shapes ~e.g. molds arid corES) used in casting metal articles. The process involves preparing foundry shapes from z7 hollow ceramic microspheres bonded with, organic or inorganic binders_ The foundry 2s shape is then detailed Ixy machining, cutting, stamping, or otherwise removing material z~ from the foundry shape to provide special shapes, letters, nurr~hers, insignia, machine ~o readable codes, etc. on the surface of the foundry sha,pe.~ The foundry shapes are used to produce detailed metal castings. This detail can be unique. to a single castzng to provide a 32 pernaanent traceable mark f~sr casting identi#ication ft~rn the time c~f manufacture to 3~ disposal. .

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~2~) Description of the Related Art . .
3 houndry shapes used to produce metal castings are typically made by compacting, 4 organically or inorganically bonded sand against a pattern or corebox cavity tee produce a molded shape. The foundry shapes have the negative shage of the pattern or corebox used b to form thean.
8 The foundry shapes are typically formed into an assembly, such that a cavity results. The 9 cavity has the shape of the metal casting to be produced. '~lherf rntrlten metal is poured to into and around the assembly and cooled, a casting is produced having the shape of the l 1 cavity, i.e. the exterior shape of the pattern and the interior shape Qf the core(s~, identical ~2 foundry shapes can be produced from reusable patterns or coreboxes, which can be used to 13 produce a number of essentially identical castings.

i~ it is oFten de$irable to detail metal castings. The detail rnay relate to specific geometrical is shaping, the addition pf certain information like part numbers, date codes, trademarles, i7 barcodes, numerals, letters, or other identifying character data. This allows the casting to I8 be permanently identified and tracked during various operations.
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zo The detail may either be raised above the casting surface or imprinted below the surface.
~ t While Ehe detail can be added after the casting is produced by stamping, welding, tagging, or machining, it is o#~en more desirable to add the detail to the foundry shape before the z3 casting is prepared, so that the detail is an integral part of the casting after the molten z4 metal, used to male the casting, has cooled.
~5 z~ ~a order to produce foundry shapes v~rith details, it is necessary to appropriately modify the geometry of the pattern or corobox. Thus, to produce a casting with unique details, it may 28 be necessary to produce unique patterns or coreboxes for each casting.
,A~Iternatively, iu t the case of identifrcation number's or codes on otherwise identicaY
castings, it may be necessary to add a unique number or code to the pattern or corebox before making each foundry shape.

A significant amount of prior ark exists for shaping foundry ~t'st~lds and cores without the 5 use of patterns ar coreboxes. U'_5. F"atcnt x,104,34' descrii~es a metlmd of rnal~,ing a z shaped foundry mold by forming a block of handed sand and then using a cutting device 8 guided by a profiling machine faun a mold cavity in the shape of the casting to be 9 produced. U.S. Patent 6,?Sb,58I describes a method for producing sand molds and cores l0 from a block of bon,tled sand using CNC contralled cutting and machining equiprner~t, t t Casting Technology lntexnatidnal, Sheffield, I,T, has also established a "Pattemless t~"
a research prograrrt to directly rr~chine molds and cores from blocks of sand using ChTC
i3 cutting and machining equipment. IIowever, these methods relate to forming less t4 intricately shaped molds and cores frorr~ blocks of sand and da not address the detailed marking of molds and cores.
1d 17 Alternately, l~.S. Patent x,220,333 describes the use of a pre-made stencil to mark a t s foundry shape, 'I'he stencil is formed by punching or cutting hales or patterns through a t9 thin sheet of material. The stencil is then placed an the moldlcore surface. Then the mold is pictured, the liquid metal ills the haleslpatterns in the stencil to create raised marks ozt z I the Basting surface, ~z 23 fihese methods tend to be limited by the properties of the materials used!
to produce flue 2~ mold, core, or stencil, in the case of sand bloBks used to produce molds and cores by ~5 machining, the material Lends to be dense, brittle, and cliff cult to machine. Tlae Ie~rel of 26 detail and surface finish that is produced may be less than desired because of the tendency z7 4f the machirringlcutting uperadon to remove material by fractutir~g chum fram the t surface. The material generally can not be mechanically pur~ohcd or itnpacteti because of 3 the tendency ttr crack in thin ssctians.
a In the case of stencils, a marerial that can be panelled car cut to farm the stencil may not be compatible with maIdlcare material and casting process. The attacl~merlt of the stencil by gtuiazg or pitming cnay adsu create casting difficulties. t*bnalty, the use of a thin sheet c~f 7 material with holes ar patterns thrc~ugli the stencil limits tl~e shape and geametry of the 8 marks that can be produced. The markks are all the same height (i,e. the thickness of the stencil material) and certain taarks can oat be pr~duced because all solid areas of the t o stenciF must he interconnected to provide support.
it t? All citations referred to under this description of the "belated ~.rt" and ire the '~L~etailed z 3 Description of the xnvez~tiori" are expressly incorporated by reference.
t4 I~I~TEF SUIVI~AI~.Y ~F T~ J~IV"TI(~N
I5 This invention relates tv a process for preparing detailed f~undry shapes (e.g. molds and caress used in Basting metal articles. The process involves preparing fa~undry shapes from i8 hollow ceramic miorospheres banded with organic or inorganic binders. The foundry 19 shape is then detailed by machining, cutting, stamping, or otherwise rernaving material 2~ from the fauridry shape to provide speBiaI shapes, letters, nurnbars, insignia., machine 2i readable codes, etc. an the surface of the foundry shape. Tlte invention also relates to a z2 praBess far preparing a t3~etal casting having a permanent i.dentificatit~n cede and a method 2~ far tracking a casting front tire bane of manufacturing to disposal. This allows the user at~d z4 manufacturer of the casting ro ~.eep traBk of inventories a~~d Basting defects, and provides zs for accountability.
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a t Uses far the foundry shapes include protatype castings, unique or one-of a-kind castings '~ such a plaques or marl~ers, castings with special geornetries that can not be easily produced 3 using conventional molding methods, and castings requiring sgecials rnarlcings like sequential numbering or machine readable codes. 'fhe ar~arings can further be used to identify the source of the shape and subsequent casting, and for quality cantrol.
The use of hollow microspheres is critical to aeet~mplishing the benefcial results of the 8 described process. The hallow micrc~spheres impart special physical praperties to the 9 foundry shape. l~Iaterial remaval is facilittated by the Iowv density of the material and by ao structure of the ;rnicnaspheres. The relatively small particle sire a~sd hollow structure 11 provide pracessing appartunities that typically can zlot be used with sand molds.
1~ Consequently, the markings on the foundry shape can be made by such simple, "low-tech"
13 methods as punching using conventional steel marking punches arid a hamzrter, t~ Alternately, shapes and warkings can be cut into the rrtaterial either by hand or using is apprapriate machine cutters, rrrilis, rauters9 rotary tools9 etc. up to and including Iaser 16 cuCting.
t'~
t$ The use of molded shapes produced with hallaw ceramic spheres provides.
several 1~ advantages for further processing. Because the microapheres are hollow, the molded z0 inserts are crushed and collapse when they are stamped to form the impression an tile ~1 surface of the insert. This crcshing absorlzs much of the rnechanicai force of stactzping sn 22 that the insert is not cracked or broken. 'This crushing else compacts any powder produced z3 by fractured spheres to provide a srrnaath, dense surface far casting.
Although solid ceramic materials like sand or ceramic beads can also ire melded to create shapes, when 25 they are stamped, the section stamped may fracture an inr~pact. ~1n the Bother hand, if the 26 insert made from sand doses nor fracture, pieces of the surface may be fractured away, 2'7 leaving a. rough irregular surface that is not suitable for casting.

t C~rtting or machining shows the same types of advantages with shapes made with the Z hollow miarospheres. Individual microspheres axe pawdexed by the cutting tool, leaving a 3 relatively smooth machined surface. O~n the other hand, when molds ar cores are made with sand and znariced by sinnilar techniques, the individual sand particles are tats away from the surface by the cutting tool, often with larger chunks, This produces a rough surface, laclrin.~ i~x detail.

8 These detailed foundry shapes ate typically arranged in a mold assembly.
After molten 9 metal is poured into and around the meld assembly and cooled, a metal casting is formed Io that contains the shape or permarsettt marking, which is a mirmr image of the geometry 1 t corresponding to the surface afthe foundry shape.
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The bonded hollow microsphere material provides an additional advantage with respect to I~. casting. Because the matexial has a comparably low density and low therxrlal conductivity when compared to sand, cooling and solidihaation of the molten metal, used to prepare the I5 casting, is slowed. The additional cooling time permits the metal to flow into smaller cavities in the mold surface and produces finer, more detailed identifying characters, 1~
19 BRIEF 13ESCRTfTIOI~T ~F TkIE SE~RA.L 'VIE'l~fS ~F TDR,AWil"~IGS
at Figure 1 is a, photograph of s. S CI~IC milling machine..

Figure ,2 is a copy of a photograph of a plaque mold insert machined from a slab of molded bonded hallow miemspheres prepared in accordance with Example 1 which shows lettering machined into the it~sett, as a mirror image.
2b 27 Figure 3 is a copy of photograph of a~ finished casting poured from ~ 19 aluminum at about zs 7~0° C, which used the mr~lded insert of Figure 2.
s 1 Figure 4 is x copy c~f a magnified (6x) photograph of the casting of Figure 3 after it was 2 gently sad blasted to remove surface oxidation, which shows the lettering 'was of very good detail>
Figure 5 is a copy of ~. photagraph of an insert made frc~tm. bonded hollow mi~rospheres, 8 I~,ving indented numer~is approximately I? mrn in height, whioh were ere2~ted by hand 7 stamping the insert using steel pranches and a hamtrter.
s 9 Figure 6 is a eopy of a photograph oaf a casting paured from ~.lloy r'~~ 19 aluminum at to approximately 73d° C, using the insert of Figure ~, which shows the raised nutt~era,Is in the 11 mirror image of the imprinted insert,.
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I3 Figure 7 is a copy of a phat~graph of a second insert made from the bonded hallnw 1~ microspheres of Example 2 that has small semi-circular e~a~ dots tar depressions in the r5 sttrf~e of the insert.

17 Figure g a copy of a maguifed ~dx) photog~,ph of the insert of Figure 7n which shflws that is the depressions on the surface of the insert had a srr~o~oth interc~al surfaee and showed no I9 signs of creaking. . , .
Figure 9 is a copy of a photograph of a casting poured from ~.lloy A,3 ! 9 aluminum at zz approximately 734J° C, using the insert of Figure 8 in a rrtcrld assembly, which shaws the 23 raised dots in the casting that are the mirror image ref the insert>

2s 1~igure I O is a copy of a magnified (6x) photograph of the casting tyf F'ig~ue 9 showing that z~ the raised dots on the castizy had exeeller~t detail and surface fnish.

i Figt~.re 11 is a copy of a photograph of a Laser marked. sa.r~care, made for comparison purposes, having readable numerals produced according to Example 3.

4 Figure 12 is a copy of a photograph of a casting produced with the ~saxtd care of Figure 12, which shflws that the detail of the numerals was of p~ror quality_ Figure 13 is a copy of a photograph of an insert, made from hollow microspheres, marked 8 with lettering of a size comparable to the numerals are the insert shown in Figure I2, which sk~aws that the detail of the letters was better and the surface ~ztish was better on the to surface of the insert made with the hallow micropsheres than the details on the care shown t t in Figure 1~ made with sand.
a i3 1~igure 14 is a copy of a magnified ~6x) copy of a photograph of a portion ml the casting of 1~ Figure 13, which further slows the detail o~ the letters anal the quality of the sutf'ace where t 5 the letters aye imprinted using the insert made from the hollow nucrospheres.
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Figure 15 is a copy of a photograph showing an insert nnade from hollow micraspheres 18 marked with a machine-readable code.
t9 24 Figure I6 is a copy of a photograph of a casting made with rite insert of Figure 15, which 2 t shows that she casting had a raised mark with excellent cast detail and surface.
z2 23 Figure 17 is a copy of a photograph of an insert made with hollow microsgheres with much 2a. of the surface removed to leave prarauding "bumps°°.
a5 26 Figure 1$ is a copy of a photograph of a casting produced with the insert of Figure I7, 27 which shows that indented marlES on the cast surface were of excellent detail and the z8 surface knish was excellent.

2 ~ETAI1~BI~ DIrSCfiIPTI~1'3 (?F THE lhlV~leT'I~T1~' 4 'The detailed description and examples will illus~te specific embodiments of the invention and will enable one sl~illed in the art to practice the invention, including the best mode. It 6 is contemplated that many equivalent embodiments of the invention will be aperable t~esides these specil:~calIy disclosed.
s For purposes of this irtver~tiott, a foundry shape is any shape made by mixing an aggregate Ic and binder and shaping the mixture (e.g. a molts, care, ~nr an insert} for tree in the casting of 11 metal parts. The foundry shapes are typically i'orttied into a "rn~lti assembly", Such that a 12 cavity results. The cavity has the shape of the n a,etal casting to be produced. '~V'hen molten n metal is pvuretl into and around the assembly arid cooled, a oastin,~ is produced having the t~ shape of the cavity, i.e. the exterior shape of the patter aa~d the interior shape of the t5 cores}. The cast metal part rnay be, for exa~.ple, an engitue block, ,piston, water pump, etc.
tG Typical metals used for casting include iron, steel, aluminum, copper, and brass.

is The shapes are prepared by mixing aiuminosiiieate microspheres attd an effective amount m of a chemically reactive binder. The shapes are typically cured by contacting the shape ~o with an effective atttount of a curing catalyst.
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The hollow alumi.nosilicate microspheres used to prepare the shapes Rave low densities, 23 Iow thermal ca~nductivities, and excellent insulating properties. The thermal conductivity of the hollow aluminosilieate rn,icrospheres ranges from about O.OS
°t~'/m. K tt~ shout ~.~
25 Wlm.l~ at room temperature, more typically fr~am about ~.1 ~?Vhn.I~ to about ~.~ °VVIm.~.
2s They typically have a diameter of about 10 microns to 350 microns, preferably with a z7 mean diameter greater than 100 microns. It is believed that hollow microspheres made of l material other than aluminosilicate, having insc.Iating properties, can also be used to replace, or used in combination with, the hallow alumittasilicate rnicrasphcrzrss.
The weight percent of alumina to silica (as Sit~2) izt the hallaw alutttinosilicate micrt~spheres can vary aver wide ranges depending ran the application, for irtstartce from s 25:7 to ~'S:2Sy typically X3:67 to 50:5D, wh~rc said weight percent is based upva~ the total weight of the hollow microspheres. It is known that hollow alurrtinosilicate microsplteres s having a higher alurnitta content are better far making foundry shapes used itt pouring 9 metals such as irozt attd steel which have casting temperatures of 1300° ~ to 1700° C
t0 because hallow alrtminosilicate microspheres having mare alttruina, haws higher melting t a points. Thus, shapes made with these hollow aluminasilicate rnicrospheres will not 12 degrade as easily at higher temperatures.

Minor amounts, less than ~0 percent based upon the volume of the hallow alurninasilicate is microspheres, of other refractories, may be used to prepare the faundry shapes. examples of such refractories include silica, magnesia, alurnitta, alivine, chromite, alurninosilicate, 17 and silicon carbide among others.
19 The density of the corttposition used to make the trtarked shapes typically ranges front to about t~. I glee to about 0.9 ~cc, more typically from about 0.2 glee to about 0.8 gJcc.
2v zz The binders that are mixed with the hollow aIurninasilicate micraspheres to farm the z3 aggregate cnix are avail known in the art, IWLost na-bake or cold-boy binders, which will sufficiently hold the mix together in a shape and polymerize in the presence c~f a cueing 25 catalyst, will work. >~~arrtples of such binders are phenolic resins, phen~alic urethane 2~ binders, furart binders, alkaline phenolic resole binders, epoxy-acrylic binders, epo~ty_ 27 acrylic-polyisocyanate binders, and silicate binders, among others.
particularly preferred zs are epr~xyacrylic and phenolic urethane no-bake ata~t cold-bay. binders sold by Ashland 1 C~

t Specialty Chemical Company, a division of Ashland Inc. "I'he, phenalic urethane cold-box 2 binders, sold under the ISGCUREII~ trademark, and the phenolic urethane no-bake binders, 3 scud t~r~der the PEP ~ETt~ trademark, are described in LJ.S. Patents, 3,485,4'7 and 4 3,409,59, which are hereby incorporated into this disclosure by reference.
These binders are based on a two-part system, one part being a phenolic resin component and the other 5 part being a polyisocyataatG ce;ruaps~r~ent. The epoxy-acrylic binders, sold under the T ISOSET~ trademark, are cured with sulfur dioxide in the presence of an oxidizing agent, 8 and are described in U.~. Patent 4,526,.219, vulxich is hereby incorporated into thus disclosure 9 by reference.
to 1 I The amount of binder needed is an effective amount to maintain the shape arid allow for 12 ef~'ective curing, i.e. which will pttoduce a shape, which can be handler!
or self supparted 13 after curing. An effective amount of binder is greater than about 3 weight percent, based 14 upon the weight of the microspheres. Preferably, the amount of binder ranges from about is 5 weight percent to about 15 weight percent, mare preferably frarn about ~
weight percent ~ G to about 12 weight percent, m I8 Curing the shape by the cold-box process tapes place by blawing or ramming the foundry 1~ rr~ix into a pattern and contacting the foundry mix with a vaporous or gaseous catalyst.
20 Various vapor or vaporlgas mixtures or gases such as tertiary amine, carbon dioxide, 2t methyl formats, and sulfur dioxide can be used depending on the chemical binder chosen.
22 Those skilled in the art will knows which gaseous curing agent is appropriate for ~e binder used. For example, an amine vaporigas mi~tture is used with phenolic-urethane resins.
a4 Sulfur dioxide (in conjunction with an oxidr~ing agent) is used with epoxy-acrylic resins.
See U.~. Fatent 4,5~6,21~, ewhich is hereby incorporated, into this disclosure by reference, z~ Carban dioxide (see LLS. latent 4,985,89, which is hereby incorporated into this disclosure by reference) or methyl esters (see U.S. Pxtent 4,'t<5(3,7 1 h which is hereby incorporated into t~

t this disclosure by reference) are used with alkaline phenoli.c resole resins. Carbon dioxide 2 is also used with binders based on silicates. fee U.S. patent 4,391,642, which is hereby 3 incorporated into this disclosure by reference.
a 'referred cold-box binders are phenolic urethane cold-btex binders cared by passing a G tertiary amine gas, such a triatlrylanai~ae, tlu-uugft the rxPVldc;d ~'oa~ndry znix in the manner as a described in U.~. Patent 3,4~09,~7~, or the epoxy-acrylic birder cured with sulfur dioxide in 8 the presence of an oxidizing agent as described in U.S. Patent 4,526,219.
Typical gassing g times are from D.5 to 3.Q seconds, preferably &~am 0.5 to 2.~D seeonds.
purge times are from 1.0 to 60 seconds, preferably from i.0 to 10 seconds, z2 Curing the shape by td~e na-bake process tadtes place by mixing a liquid curing catalyst 13 with the foundry mix (altemativeiy by mxxir~~ the Iiquid curing catalyst with the foundry 14 composition first), sloping the foundry mix ct~rtagning the catalyst, and allowing the a5 foundry shape to cure, typically at ambient temperature without the addition of heat. The 16 preferred noTbake binder are phenolic urethane binders dared by raxixin~
with a liquid c 7 oatalyst. where the liquid curing catalyst is a tertiary amine and the preferred no-bake r8 caring process is described in U.S. I~at4nt x,485,797, which is hereby incorporated by t~ reference into this disclosure. specific exammples o~'such liquid curing catalysts fnciud~ 4P
20 alkyl pyridines whexein the alkyl group has from one to four carbon atoms, isatluinaline, z 1 arylpyridines such as phenyl pyridine, pyridine, acridine, 2-ethoxypyridine, pyridazine, 3-ahloro pyridine, quinoline, I~-rnetbyl imidazole, 1~1-ethyl irnidazale, 4,4°-dipyridine, 4-a3 phenylpropylpyridine, 1-rnethylbenzi~nidazole, and 1,4-thiazine.
za zs ~B~REVI.ATIt~NS
Z6 'fhe following abbreviations are used:
2~

t detailing rIlG~11in1ri~, Cl3ttLri~, 9tarrit79ri~, Orriht5~5in~, nr ~rt~18rw15~.

2 r'Cnlnvinv~ n~ater'L~I from t1W
ruunclry ~l~pr LV prVVIt~ SpeCl~1 3 shnp~~, letters, numerals, insigL~.ia, ntaachine readable ec~de~, 4 etc. on thae Sutftide of a foundry sllapc. .

E k'oundry mix a mixnu~e a foundry a~rrgata grad a fouaidrybinder.

R ~ Foundry si7~riea tt~.old, o~te, irascrt, or ottaer shape made ti~tsr~s a Foundry cwix used t0 cast metal.

1 t Mold essetnblyan asseatlbly of molds, cores, aatdfor inserts trlade tratm a La foundry aggregate (tyjxieally sand) ~i~d a fouaadry binder, t3 which s5 placed iii a uastin~
,~.yseaa~ably to provide a shape for is the oa~;tillg, iti PEP ~aE~'t1~1;~1000fX20d7(1a three-part L-~r~..la~kC pGeno~i4 tta'ethane amldte Cul'8d binder 1 ~ ~ liavuy a part I to Pans II ratio of about 5145, and about 3.C1'~n ix amide catalyst based an the fart I, .void by Asl~lal~d specialty I~ GWhG"fI11Gd15 lf1'irtSPfCilt Q~~$hIt911A.I
1.L!(..

21 5f's'f nticrospliercshollow alutrtinosilic;~te miorosphere~
sold tsy Pty Corp4ration 2z hclvi~~ a particle arse of ID-'~
X9.1 ~iticruns imcl an ahunina '..a content betwceu ZS% to 33/a by w~ight baSBO apart tho weight of the miorospheres.

z5 2s 5~G miorosphereshollow atuminositicate microspla4c~es s~alel by p(~ ~arporation 27 havi~fg a particle sire of IU-300 tiliecotts arid an alutnina t content of at !cast 4tN!~ by wei,~i~t based urn the weight of z the Ltiieruspher~s.

~XAIft#'L>N;~
While the invention has 6tcn dC5Gnt7ca with referonce trn a !referred ennuriintmr, tlivse s skilled in the art will understand that various chan~Cb may be made and equivalents may be o stt>bstituted for elements tlf without departing from the scope of the inventibn. 1n 8 ittan. ril8rty nlbdifcCatiOnS may be made to adapt a paslcula~ >tituati~n rn-material Mr tha 9 fiGacitings of flit inv~tian witlxaut aepartins~ from tlcC esscc~tial seupr ll~rcoG Thearofure, it to is intended that the invenrion. not be limited to the particular ~nbodimenc disclosed as the 1 t best toads contctnplatcd for carrying out this invention, but That the imrtnttan otriil inolncic f ~ all tmbodimttlts ftiliinS ~~ithin the scope of tJ~c apptndrd cLaicus. Iv tFiis etppIiaalimi, all a units are in Ehr rnrtric Systole attsi all atnaunts and percentages are by weight, unless 14 otherwise expressly indicated, i5 t6 t7 Ex$rnFle I
is (7tyreparatiwn of costing having Lmgrittted mttt~lt,in~ frem rt mold i~set~t havittg t~ machitnad lettering made fr~onn, hollow tnicrespher~) ~0 ~I A platNe moil insert was rnachincd from a slab of ucuIdetl mnteri~. 'fhe insert was z2 produced by raixing eight weight percent of PBi'S~~YJ ~C10~OIX'~400 with $LG
x3 mi~osphet~s. Lettering was machined into the insert as n mirror itn$gc to create the mold, z+ using a HAAS CNC milling machine (f~igus~ I ) with a half rotted, 90° point, carbide tool turning or 7~tip rprn and with a feed rate of LS inchae per minute. The tnaohined insert is z6 shvwtt in Figure 2.
2& The manorial machineri easily at a feed rate o~ LS iue:hes prr mintate and it was BxpeCtBd 29 ilyak khr- matrsiaL could be machined ac a feed rate up to ~0 to 8~ itlche5 per miaute. 'fhe se caalutg Jid clot get diny during the eutcitlg pruoess and t#ie mflid held togcttyGp, cvctl when 1~
~> . , ~ ,.,.n Av . NrYt~ ~ rvn avhe, . py=r;~, .,r .u.... . v. U:Sn xvry.wv ow w ..

i it ores nar delicately handled. Loose anaterial from the mold u~as easily removed during 2 cutaz~g using a small portable vaouum cleaner.
s 4 The cnachis~eci meld slab was then inserted into a mold assembly and molten 5 aluminum, laavirtg a terngeracure o~ about 730° C was poured ir~ca the Cavity formed by the 5 mold assembly. When the metal ctroled. the finished casting (1'iguse 3j was removed frem ? the mnltE.
s The cast~g was gently sand blasted to remove surface oxidation. fibs lettering produced 10 by the machined slab showed very food detail (Figure 4j, e~qua,i to a glaque with the t I lett~eriug produced froaaz a lettered pattern is 13 ~xamplc 2 1~ (Yreparatfot~ mf easticnga having raaae~t moarkin~a FPnro ~nnid ingerf~
y wail stamped marks 16 A small insert ~f molded material mode foam SC'xT microsphorCS 6andcd with ten weight 17 percent rFr~srTf~ xlooc~ixzoao was hand stanpcd using steel punches asad a halzuner to is create a marked insert with indented nutrtber approxitriately 1~ mnt let height (1~iguee 5), 19 'xlte insert was placed into n mold asseml9ly elate ntoltCn ,dray Cast iron, having temperature Z4 of approximately I~#~5° C;, vsrs.~ poured intro the cavity formCd by the asseinbly_ 'fhe .
21 rcs~rltixy casting c;0tptaiued raisrGd numbrrs in the mitror image of the Lrnprint8d itlBeCt 22 (F'i~urm s.j.
24 A sCC~nd insert of similar molded material wss n'ar:hieu p~lnChCd using a P1N~TAMP ~
25 marking device mauufactrwed lsy fir&c~is fi~w:lmols~6ies Inc. fibs device pd'tfdttC2d small 2s srmi.c9rcular dots or depressions in the surface of the insert (higure 7).
These depressibns :;7 had smooth internal 9urfaCC and showed no signs et' creeks ~Figurc g)_ The ittsc~t ~rxs ~ placod iri a mtild gsscmbly and tho o'ctald was poue~d will All~r~r .~,3I~
aluuunurar at t aplrroximstcly 730° ~, The reeulling casting (ri~n~re R) crmtnined raised marks ~n~~r m araiaior image oi' the in4Crt. Tile 1'alS~Bd d0t& Showed ext:allrcat entail arid Sur'FsCC ~irilSl!i 3 (Figure lf~.
Egamgle 3 gtfd CompaVxtive l.x:amjtle A
g (greparatlaa of cxsting.g hawing hotth raised arid indented tncrl~d~g from laser asut molt! f119Crts mode from bonded huttuw mlcrospherts atad bonded wand j s A series s~f mold inserts were molded using ~aGrt microsl~iterc:~ and inn percent by t~reight to of IgOCTJREG~I 45Q1852 bitndcr. 'The molded installs were marked using a ProScrrpr(& least tt rnarkmg systezz'a provided by T.clGSis Teehraoln~ics, Inc. several insserts were placod into a t~ mold assembly. A sample of a laser marked sand core was alsco prneu;ned for compar'ssan, 13 The .sand cure and marked inserts were placed in a mold asserttbly and poured with alloy t~ A319 alumina~m. The resnltirg cast;ng was examined fox the level of detail atx! surface is finish.
n m '19,e laser martccd sand sore (Figure I l) pradua~, readal;!le l2tt~rs~ but the east sutfdcc aml t8 detail ware of lruoi duality (figure 12}. A marked insert with lCttering t1f Compable sire 1~ {Figure !3) produced much better saui"av:r and detail (Figawrc' I~.). A
marked insert ~rith a 2t~ maschme-reodable code out into ~e insets f.Fiptlre 13y produced a raised mark- wiu ti esceellent cast detaal and surface (Figure lti}. A t»t~Cd insert vvid~ much ae the sur~ee 2: retucaved to lexvr pautt'udutg, "bumps" (Rigure I7} prodttc~.ci indcatcd rn$r~s e~tt the east z3 surface, again with excellent case detai! and surface (Fixttrr I S).
2~
is is

Claims (11)

1. A process for preparing detailed foundry shapes which comprises:

(a) mixing aluminosilicate microspheres with an effective binding amount of a foundry binder to form a foundry mix;

(b) shaping said foundry mix to form a foundry shape;

(c) curing said foundry shape; and (d) detailing said foundry shape by removing material from said foundry shape.

2. The process of claim 1 wherein the detailed shape is a mold, core, or an insert.

3. The process of claim 2 wherein the foundry shape is detailed by stamping, embossing, machining, or cutting.

4. The process of claim 3 wherein the detailed foundry shape contains one or more numerals or letters.

5. The process of claim 3 where the detailed foundry shape contains a bar code, design, or a label.

6. The process of claim 5 where the detailed foundry shape can be scanned and identified using an ultraviolet light scanner.

7. A process for preparing a detailed foundry casting comprising pouring molten metal around a foundry shape prepared in accordance with claims 1, 2, 3, 4, 5, or 6.

8. The process of claim 7 wherein the mark on the casting is raised.

9. The process of claim 7 wherein the mark on the casting is imprinted.

10. A process for tracking a metal part comprising:

(a) preparing a marked casting in accordance with claim 8 that is permanently fixed to said casting; and (b) reading the permanent mark on said casting.

11. A process for tracking a metal part comprising:

(a) preparing a marked casting in accordance with claim 9 that is permanently fixed to said casting; and (b) reading the permanent mark on said casting.