Note: Descriptions are shown in the official language in which they were submitted.
CA 02426515 2003-04-22
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.
7
CLAIIvi Tf~ 1SIE.T(~~ITY
9
1 o Not Applicable.
1I
12 ~TATEI~1,EN'T' E.EG.A.R.DINCi FEDERALLY ~PON~OItEI~ I~E~EA1~.~EL C?1~.
13 DEVELt~FIVLENT
14
~ 5 Not Applicable.
1~
17 REFERENCE T~ A NxZ~It,CIFIIyHE API~ENI~IX
18
Not Applicable.
2p
2 t BAC~.I~t7UND t~F THE I~VENTIC~N
22
23 ~ I ) Field of the Invention
24
~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. .
1
.. ~ ~ _~
CA 02426515 2003-04-22
~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.
14
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.
1~
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
2
CA 02426515 2003-04-22
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.
4
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
3
CA 02426515 2003-04-22
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.
z~
a
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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.
28
5
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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.
7
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.
1~
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..
22
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
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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,.
I~
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.
16
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>
24
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.
CA 02426515 2003-04-22
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.
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.
tG
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.
CA 02426515 2003-04-22
1
2 ~ETAI1~BI~ DIrSCfiIPTI~1'3 (?F THE lhlV~leT'I~T1~'
3
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.
17
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.
2!
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
CA 02426515 2003-04-22
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.
13
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~
CA 02426515 2003-04-22
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~
CA 02426515 2003-04-22
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,
1I
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~
12
CA 02426515 2003-04-22
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. .
5
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.
10
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,
15
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~~$hIt911A.I
1.L!(..
21 5f's'f nticrospliercshollow alutrtinosilic;~te miorosphere~
sold tsy Pty Corp4ration
2z hclvi~~ a particle arse of ID-'~
X9.1 ~iticruns imcl an ahunina
'..a content betwceu ZS% to 33/a by
w~ight baSBO apart tho
weight of the miorospheres.
z5
2s 5~G miorosphereshollow atuminositicate microspla4c~es
s~alel by p(~ ~arporation
27 havi~fg a particle sire of IU-300
tiliecotts arid an alutnina
13
CA 02426515 2003-04-22
t content of at !cast 4tN!~ by wei,~i~t based urn the weight of
z the Ltiieruspher~s.
3
~XAIft#'L>N;~
While the invention has 6tcn dC5Gnt7ca with referonce trn a !referred
ennuriintmr, tlivse
s skilled in the art will understand that various chan~Cb may be made and
equivalents may be
o stt>bstituted for elements tlf without departing from the scope of the
inventibn. 1n
8 ittan. ril8rty nlbdifcCatiOnS may be made to adapt a paslcula~ >tituati~n rn-
material Mr tha
9 fiGacitings of flit inv~tian witlxaut aepartins~ from tlcC esscc~tial seupr
ll~rcoG Thearofure, it
to is intended that the invenrion. not be limited to the particular ~nbodimenc
disclosed as the
1 t best toads contctnplatcd for carrying out this invention, but That the
imrtnttan otriil inolncic
f ~ all tmbodimttlts ftiliinS ~~ithin the scope of tJ~c apptndrd cLaicus. Iv
tFiis etppIiaalimi, all
a units are in Ehr rnrtric Systole attsi all atnaunts and percentages are by
weight, unless
14 otherwise expressly indicated,
i5
t6
t7 Ex$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 ..
CA 02426515 2003-04-22
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
319
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
15
CA 02426515 2003-04-22
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
8
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
