Disamatic Gating

8/12/2019 Disamatic Gating

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MixedPressurizediNonpressurizedGatingSystem forVerticallyParted Molds

J. AlvaFtttndryConsuItoulCaneri, ITALY

ABSTRACT'l he protltrttion o.f tustittgs using t't'r'tit'ullt'turtetlmoldirtg(Disumutic)lincs is ulrcud.t wallcstahlishcdin thcJltuttdrtndustt vH igh ntoldingstceds urtd eust'ol otat otion untlntuitttenon(eseentto bc the .r'.i1o . 1( ( ,,r.r Nct'etthelcss. tltc hi,t,ltnretal stectlstlereloteddurin,e, ntoltlIillirt,q,contnrrltlt'leudt u hiphtr inci-tlartre rl st rut dua to ,surlutc deletts (slug. subsurlute hlou's,c,rr t,.r.r rlc lorrg h n t s s, c tL ) u' he rt L o nta r c d t o l hc ru l e s c.rpe t i e rt c e dn itltits htri:tttlal ( ounterl)arl

'l'o face this situution, lurtdries.in gerttruI.devcIoptheit owngltltlgs|st(nts, n'ltitlt t'ur|upon putern loIoLttr)r ( L/.r/irStott.figut'uion'l his uptrooth generallt'lentonds sevcrul tesfs ot'triuls lta.f'otcproduttion(on surlThis te:tin,gs timL-(r,nsuntitt,q.und the


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E.tunttlt'lSuppose in Fi-s. I thiltthe unitary, casting weightisI kg (2 2lb). that Hl- l-5 cnr (6 in.). Hl- l5 crr ( l0 in.) ancl H3 =3-5 cnr (1,1 in.). that the fillingtinre firreuch custins is lour scconclsancl that "c"= 0..1. Solvc tbr thcingatc cross section inlll levels.

Pu - lll = 0l-5 kg/sec < > -36 cc/sec (unitar'flowrate)Pu =c Al.r2g Hl=0.1.A1rl 9li0.l5=.16cc/sec

Solvirrgthe equation wefirrd:

Al= 0.53 cnrlA2= Al\ l5/15= 0..11 crn'A-l= Al.\l-5/3.5 = 0.15 cnrl

With this sirnplc calculation.llowrates ure balanced in all levels.

lfu,e assunre a casting ,ielclol 507. the expectecl pouringtinrcwtuldbe around 7 8 seconds. Still.the cxstings in the clif'ferentlevelswillnotfillsirnr.rltarreousl\'.In thcsc conditions.the fillingofcastin-cs willproceec'l in the sequence bottonr => top lcvelssincenretal pressure is exercisecl by thc gatin-u svstcrr over the loweriugatcs. even bclbre the systenr is lull

lf tlowratcs xrc balancecl. the tirne lagbetrveen the fillinsof acastng placed in the bottorrand that xt thc toplltost level norrnlrllycan bc in the orcler of one second Otheru,ise. it rnav exceed tu,crscconds. since l-illingrvilltend to be progressive: that is. that thewhole flowrate willbe nbsorbcd by thc bottonr lcveland onl,alterfillingthis level willit fillthe next Icvcl.and so on. However.balancingfloivratcs in the differentIevels rr illonl,reduce the tintela-r but not clirninatcturbulenceand the associated ploblcmslslongrs the speed at thc ingates in the ciif'ferent levelsrcmains asbefirre. Wcshallsec latcl how toreduce the speed.

Control ofSlagA s'stern l ike lhat of Fi g. l c lcarlyr.r' i l l not prevcnt s lag pal ticles frol'ncntering the castng cavities as long as it does not have horizontalru nucrs where slag can lloat and col lect.On the other hand. cons idcri ng

that slag flotationis favoredb, lowfcrrostaticheads (whichmeansreduced turbulence).rit is clcarlv coltvelrient fbrthis scope to placethe horizontalrullneron top of the pattertr plate (Fig. 2).

This arrangement is not ncw.r it has onl, been re finedfurther. Forthe same reason. the worstsolutionis to placc tlre runners on thebottonrof the pattern plate 1Fig. 3).

To ensure that slag can floatand collectin the runner. theIollouing mca\u[cs shouldhe tuken rFip.] r:'l

(a) lt)2 Modiliedgating system wth top runner(schematic)

l. Choke rt thc cxit.ln so doins. thc runner willbecorncprcss u lizccl

l. Keep a rlininrurnsaf'ct,distilncc "cl"bctweelt thr- p(ruringcuplnd thc ineate lt is suggested lt lerst l(X)nrrl (.1 in.).

J Reducc adcquately the rletal spccd in the runnertoacceletrtcslau scpnration This can be accornplishedb' kcepirrgIrunner:chokecrossscction ratiobctwccnl:I and2.-5: I Higherfigures arc not moreeflective.

As aclclitionallreusurcs. thc tirllolling are suegesteci:

l. Extcudthc runner past the lilstgate (around 30J0 rrm. 1.2-5| -5 in.)2. Tapcrthc runnerendin ordertospeed flowstabiIit.,clurinsthe

early staee of pouring.-1. Exclta f irstclroke atthepouringcuprunnerjunction,cspcciallv

il strearn inoculationis practicecl

Influenceof Automatic Pouringln shil'ting frornrluluulto lutontatic pourin-u (tbr instance withPrcsspour furnaces).an iltcrcascof flowrate is comllonlyerperi-errced. The rcrson is obvious:the increrscd pressure heiqht ovcl thcchoke irlpliesan irugnrentationof l'lowrate. In the author's expcricncc.

the systern wolks.apparentl,havingan aclditionalpressurc hcichtol'arourrd l0 crn (.1 in.).

E.tunttlc2 Supposin-u the runncrchoke (printar ingutel irplaccd at a level ivitha ph,sical hcightof 7 crr (2 [i in. ) in re\pr-ct tothe nroldtop. solvcthe systenr of Fig.2. (Rest of clata as in Ex.| )

The primaryrunner choke (Ach ) w illrc-tu late the flowrate firrthectrtires,stenl (six castings) That is:

P = 6 36 cc/sec = 2 l6 cc/sccbut P=cAch.r2.g.(7+10)solvingAch= 295 cml

This rneans a gate clitrcnsionof -5x57 rnrn(0.2x2.4 in.). Whcrcpossible. it is su-cgested

thatgate

heiehtsnot

cxceed 5-6 rnrn(0.2

0 2-5 in.).

Runner rrca: Ar= 2.5.Ach= 7.1 cmrRunner dimens: l9x3llrnm(0 8x 1.6 in.)

Fig Fig3 Typicalgatng arrangementwithbottom runner

ring cup choke

Verlical segmented

SecondarY ingate

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Pu = c'A I r,2'g'( l5+I0) = 36 cclsecwhere AI = 0.4 cmr (or 40 ntlnr)

A2= 0.4.ri( l-5+10)/(25+10)= 0 34 cm'(3'lmmr)A3= 0.a. ( l5+ t0)/(3-5+l0) = 0.30 cmr (30 mm')

Note that when calculati ng the casti ng i ngatc cross scction ( secondaryingates). the overprcssure o1- I 0 cm (4 in.)has also been considered.

Reducing Turbulence in the VerticalRunners

To reduce turbulence in th i s part of the system. take i nto considerationa conccpt appliedin hydraulics to reduce kineticencrgy in openchannels where water flowsdo\\'nstream througha stepped channel(Fig.a).

This concept can be recrealed in the moldby avoidinga straightverticalrunner and substi tuti ng i t wi th a stepped tlne, as shown i n Fig.2b. LiquidInetal in thissystem is forced lo continuouslychangedireetionf, it gocs dou n rcross lhe pilrling.

Additionally.choke the ironeach time the runner changes direc-tion (see also Fig.5).In doing this,we get three effects:

l. Liquidmetal falls over liquidmetal and loses its kineticenergy in a cushionedway (splashingis thus minimized)2. Due to this sortof'labyrinth,time lag between lcvels is nearlyzero: all levels start to fillnearlysimultaneously.

3. As longas casting gates (secondary gates) no longerhave thetask of regulating flowrate, they can be made larger.Consequently.metal speed is clearly reduced.

The gating system so devised can be defined atths stage as amixed pressurized/nonpressurized one.

\^-rsSS.rr".rr

Fig4 Reducing kinetic energy in an open channel (schematic)3

Fig5 Reducing kinetic energy, turbulenceand splashing byconsecutive chokes as in modifiedgating of Fig 2, nonpressurizedsection(schematic)

AFS Transactions

DefiningChokes in the VerticalRunnerE.ru n pl e -1 The fi rst part of the verticalrunner, starting at the primarygate, willconveythe entireflowat the rate |.5 kg/sec or215 cc/sec.Past the firstlevel.we should chokethe runncrin order to allowthatonly213 of the mctal flowcan go throughas longas the remainingl/3 serves to fillthc first levcl.

How can this be achieved'lAt level l, the unitarychoke percasting is,10 mmr (whichwas the calculated unitarygate crosssection). Th is means that sixcastings at this levelwould demand 640= 240 mmr of choke whiletbur castings (2/3 of totat) willdemand213 Q4O). whichmeans 160 mmr (Achl).

Therefbre, this is the choke we should create at the firststep of theverticalrunner and. theoretically,.iust aftcr the top levcl ingates. Pastthe second levcl,we shouldchokc the Inetalflowfor twocastings(last level) whilethe diff'erence willserve for the second lcvel.

Thus. we reason in the same way:at the second level.the unitarychoke percasting is 34 mmr. whilefor two castings thc choke willbe2 34 = 6itmmr (Ach2).This is then the choke at the runner just afierthe second level. Errorsduringexecutionof these chokes in thepattern shop willalter the distributionof flowin the differentlevelsbut willhardlyalter the totalpouring time. Thechoke ideallyisplaced u-ridwlybetween levcls andit is created, preferably,byoverlapping.Sections can appear surprisinglysmall but it is just rntmDresston.

VerticalRunner DimensioningIn the author's experience, a ratio of l.-5:lcan be kept between therunner (Av)and the choke relativeto the portionunder examinationWe have thcn:

Avl= l.5.Ach= I 5.2.95=1.4 cmr(say 2lx2lmm or0.8-5x0.t35in.)

Av2 = l.5.Achl= l.-s.1. = 2.4 cm'(2 | x l2 mm or 0.8x0.5in.)

Av-l= .5 Ach2= 1.5.0.b8 = I cm-(21x5mm or0.8-5x0.2in.)

Verticalrunners of the nearlysquared section in the firslportionare prcferred.Afterthis portion,and fbr simplicityof execution,oneof thc dimensions canbe kept constant. The junctionbetween theprimarychoke (Ach)and the vertical runnershouldbe made in sucha way as to avoid any accidental choking.

Secondary Ingate DimensioningAgain,in the author's experience,a ratiobetween 1.3:land 1.5:lbetween the casting ingate's cross section (Ax')and theirrelativechokes (Ax)is recommended.In the case under study, we wouldhave:

Al'=1.3 Al= 1.3.40= 52 mml(or 3x l7 mm or0. 12x0.7 in.)

A2'= 1.3.A2 = 1.3.34 = 44 mmr(or 3x l-5 mm or0. l2 0.6 in.)

A3'=1.3.A3= 1.3 30 = 39 mmr(or 3x l3 nrm or0. 12x0.5 in.)

The gates definedin thisway can be arranged in order to fillthecastin-q (withor withouta riser) eitherfromthc bottomor fromtheside or l-rom thetoD.

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PRACTICAL APPLICATIONS: A CASEHISTORY

Figure 6 shows a typrcalrnultiple-pnntcastng that was desrgnedtbllowingthe aforementionedprinciples.Tomake fulluscof patternsurface. secondary ingates we re elimiuated. Thisis strongl,'advocatedi n risered casti ngs, because riser necks can pcrformthat role pcrf'cctly.Chokes are. in this.case created between risers.

Tltcprohlent:Fifteerr castings (0.6 kg or l.-32 lbeach) arrangednonsymrnetricall,inthree rows and three (equallyspaced) levels areto be producecl in ductile(spheroidalgraphite)iron Also. H |

=130

mnr (5.1 in.),H2 = 230mrr(9 in.) and H3 =330mm(13 in.).Thus,spacing that is regularis 230 - 130 = 100 mm (4 in ). Assume 43%castng yicld.0.6 for"c"(frictionfactor') andautomaticpouring.

ln order to showcalculationsrn a real case. a casting p()uringtinre(tc) of four seconds u,illbe assurred. This decisionwillbejustifiedlater. In reality. totalpouringtime (t) rather thancastirr-upouringtime(tc) is normallyused to def ine the gating systern. Thiswillnot aller thc pouringrate but the pouringtime. The unitar,pouringrate (Pu) is:

Pu = casting wei-uht i tc = 0.6/l = 0 l5 kg/scc < > 21.l cc/secSolvingforA | . A2 and A.3 usin-e Equations l. 1 and -5:

A I = Pu i (c. 2.980.(I 3+ l0 = 2l ll27.4 = 0. I7 cmlA2= Al\H l/H2= 0. 17.\(13+10)/(23+10)= 0. I4 cnrlA3= Al\Hl/H3=0.17.\(13+10)/(33+10)=0 l24cmlTo define the chokes between leve ls. it mustbe remembered that

the pattern layoutis not s,mmetric. Thecentral row is single whilethc two other rowsare double (Fig. ).

Startingwiththc single row, we reason as befbre: thc firstpart ofthc vcrticalrunner willconvey the entireflowat a flowrale relativeto three castings (3 Pu or6.1.2 cc/sec). Past thc first level.we shouldchokc between risers in order to allowthat only 2i3of the metal f'lowcan go through. At levcll. the unitarychokepercasting is Al=0.17cmr whilefor three castings it is 3.Alor0.-51 cmr. Thismeans thatthe chokebetween levels I and 2 should be 2/3.(0.-5l) or 0 34 cmlt6x6mm or 0 25r().15 in.t.

At level 2.the unitarychoke per casting is 0. l4 cmr while for2castings it is 2 A2 or 0.28 cmr. Thus. thc choke betweenlevels 2 and3 willbe l12.(0.28)or 0. l4 cnrr(4x4 rrm or 0. l-5x0. l-5in.).

For the double rows.the figuresfor the consecutive chokes willbe exactly twiccas much as those for thc single row. So. in orde r fromtop to bottom.they w illbe: 2.0.34 or 0.68 cmr (8x8 mm or 0.-32x0.32in.1.2.0.l4 or0.2R cmi t5r mm or{).2r1).2in.).

Now, solve for the pressurized section consideringa prcssureherd of 7 cm (2.8 in.) over the primarygates in the top runner,knowingthat the total flowrate is P = l5.Pu or 321 cc/sec:

Ach= P/(c. 2.g.(7+10)= 2.93 cmr (0.45 in.r

This sectionis relativcto three primarygates where two ofthemare cqual and the other conveys onlyone-halfof thc flowrate.Mathematically,thc number can be expressed as 2.5.

Solving for the biggerone s:

AchI = 2.9312.5= l.l7 cmr (0. l8 in.r)(say 4x29 mm or 0. l5x 1.2 in.)

The small one:

Ach2 = Achl12= 0.-59cmr (0.09 in.r)(say 3x20 or4x l5 mm, or 0. l2x08 in )

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Considerin-u that onerunner is comprisedol-one double rowandthe olher is comprised ofa singleand a double rowand. witha raticrAr/Achin each case of 2.-5. the runners' cross sections lre:

l. for the small runner(leitone):Arl= 2.5.Achl= 2.-5'1 .17 = 2.9-3 cml

(say l2x2'1rnrn or0.-5xl in.)

2. firrthe larger runner(rirhtonc):

A12 = 2.-5.(Ach l+Ach2)= 2.5.1.7-5 =,1.38

crnl(say 15x30 nrn or 0.6x I .2 in. )Aguin.rnathematicallyexpressed, the nurnber of rulrners is

l-213or 1.67 sincc this is thc ratioof flowrate ther convey. Thisfigureand that frornthe primarygates willbc cmployed fbr solvingwitha sofiware prograrn. The choke bctween the pouringcup and toprunners can be made one-hallol the relative runner'scross scctionThat is. theirdincnsionscarr bc. respcctively,l2xl2mm (smallerrunner) and l -5x l-5 mnr (biggcr runne r)

Due to pattem layout. thesaf'ety distance (100 rnm or l in.)between pouringcup and firstgate was not kept. Still.castings wereclean (Fig.7). Note,also. that there is littlediffcrcnccofappearancebetween castin-qs in the diff'erent levcls.See. also. the contrastbetween the surface of the top runner(prcssurizecl section)and theriser and castings (nonpressurizcdsection).

The total cxpectcdpouring tirnc(t):

t = tc l(X)/castingyield= 1 lj0l43= 9.3 secThe actual pouring time as measured in the fbundryis 8.6 scc,

whilethe true castins yield is;12%(pouredweight: 21.42k-u). Theactual pouring rate is then:

p = pcrured weight/r= 21 .1218.6 = 2.-5 k-e/sec (-5 -5 lb/sec)

Traditionally.in this fbundry. itis preferred not to exceed 2.5 kg/sec (-5.-5lb/sec) when pouringin verticallyparted rnolcls. This is thereason why tburseconds was chosen for starting calculations.In theauthor's opinion, 3kg/sec (6.6 lb/scc) normallycouldbe attainedwithoutdifiicultiesin nroldinglines of thistype. Nevcrtheless.thesand + machine + patternconditionswilldictate the limitsin eachpartcu lrr situation.

Fig6 A view ofa practcal applicaton ofa mixed pressurzed/nonpressurized gatng system for vefticallyparted molds (Photocouftesyof Peraro For Foundry, Rovigo, ltaly)

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Comments

This approach can appelr too sinrplisLicfbrpurists Thc author doesnot claim that thcproposed approach rcspccts l(X)c/rreality,butreiults confinn,very positively. thc claimsof the r-nethod: clean andvisuallyappcalirrg castingsurl)ces. Sonre authors suggest diffcrentI'rictionf actols fbr cach componcntof the gating s,stem Thisapproach leads to rthcr snrallrunners and incrcased frictionlosses.

In thc author's expcricncc,providcdthat the top runner/pritnary

choke rale cross section is not lower than 1.8. a unique "c"can beappliedtbr the cntircs)/stcm. By thc way. depending on the ntcthodofrourin-{.itcan vary between0 3 and0 6 Clcarly. Iowerfiguresarenl()rc ildcqulllr lormlrnuulp()urinS.

1n these conditions.pouring tirne is directlyrclatcd toprirnrrychoke cross sectionand varies proportionally withit li the ratio islower than| 8. ths proportionalityis invalidand it bccorncs verydifficult tounticipatcpourin-{tirne with,uoodprecision(l sec)Auother applicationis shown in Fig.tl.

USINGA SOFTWAREPROGRAM

Calculationofthe entiresystem appears lengthyand. in frct, is Forthis reason. a specificsoftwarewas dcvclopcd bythe author aroundfiveyears ago.

The sotiwarehas urrcler-{oneseveral modif ications to 'itthelbundr,nccds and also to improveits friendlinessin operation.It iscallecl "Quickalc-MixtoPress" and Figs.9a and 9b show thehardcopres relative10 thc cxanrplcdeve lope d rranually.("Quickalc"isthe nirne of thc softwarcpack of which Quickalc-MixtoPress is t

Fig7. Close up ofFig 6 showing castng surfaces in the dfferentlevels Note the top runner surface (Photo couftesyof Peraro ForFoundry, Bovigo,ltaly.)

AFS Transactions

part and is intended forthclronFourrdry Method Department.)lt iswritten inIBMBasic and can be run or.r any PC 100% conrpatiblc.

[n the top hali ofthe hard copy (Fig 9a) the data scction can beseen The spacing between levcls(data n.6) substitutes the entry ol-H2. H3,etc. (the rest of data is sclf-explanatory).

Frornthe additionaldata shown in the lower half.a preliminaryevaluationof casting yieldcan be madc. In lact. give n thc weightofthe pouringcup, the weightol- thc risers/casting, the lengthof both

thc top runner and thc vertical runner(allof thcm known),theprogram nakes an evaluation of casting yicldwithan excellentapprox irnation (13c/c in th is casc aga inst the ctual 12c/r.) U sual I y theerror is around 2-37.

Aficrintroducingthis data. the programdefines a preliminaryvalue of scven sec for the pouring timcbut withtwo constraints: theresultant pouringrate should not bc inftriorto 1.5 kg/sec and shouldnot exceed 3 kg/sec (thcsc limitscan be varied at wilI ). Subsequently.it defines all dimensionsas in the manualcalculation(Fig.9b).

Thcn it is possible to modifyany data plus pouring tirne, thicknessof primaryingates and frictionfactor. In our L^ase. the system wasdesigned fbr a pouring tirncof nine sec (in place of seven sec) toavoidexceeding a flowratc of 2.5 kg/sec.

CapabilitiesWithMixto-Press,it is possible to solvcthe fbllowingcvents:

l. Castings equallyspaccd in the pattem platc as in the example,whcthcror nol arrangcd symmetrically.

2. As above, but withcastings spaced arbitrarily.3. Sirnultancous fillingbut withdifl'ercntiated f'lowsin the

diff'ercnt lcvcls. This is the case. basically. of singlccastings.

Applyingthe CADTechniqueFigure l0 illustrates examples ol'the joinlapplicationof Mixto-Pressand A UTOCA DI 0 lrom Autodcskto produce the detailed drawingsof a multiple-printductile ironcasting forthepattern shop. Bendin-qof the verticalrunners (Figl0)pcrrnitsan increase of the sat-etydistance "d"( see Fig. 2).

This version of CADis able to ernulate a DOS interfacewhiledesigning, thusallowingthe loadingof any utility.which,in thiscase, is the software under discussion. When calcu lations are finished.it is possiblcto go back to the drawingunder exccutionto completethe design wrthoutthe need oi reloadingthe CADpro-qram.

Fig B Another application ofthe proposed system (Photocouesy of Peraro For Foundry, Rovigo, ltaly)

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* Quickalc-MIXTO-PRESSt

DATA

l.Casting weight .....kg:? 0.63.Nurber of horiz. runners....:? a.6'75 -Press. head f irst level ' . 'm: ? 1307 .Numbe of ingates,/casting. . ' : ?g,Numberof pri-marygates. . . , :? 2.5

lrleight of pouring cup. . . . ..kg:? 2.5Ileight of riser/casting..'.kg:? .5Top runners tot aJ Ienght . . .m: ? 470Vertical runners lenght....m:? 290Expected casting Yield. . . '..%: 43

* Quickalc-MIXTO-PRESS*

DATA

l.Casting weight. .".k9: .63,Nmber of top runners,....... 1.675.Press.head f irst level-. . . .m: 130T.Numberof gates/casting"...: 0g.Nmber of primarY gates....-:2-5

XJUL I

Pouring time... .sec: 9Pouring rate.. ......k2/sec: 2.32Pour.cup choke. .m: 15 * 15 - 1'Z * 72

CONCLUSIONS

Througha simple example.and using elementaryhydraulics.theauthor has reviewed theprinciples tbr designing verticallypartedgatrngsystems.

A proposaltobounteract the effects of turbulencein the verticalrunners has been presented. In this way. a mixedpressurized/nonpressurized gating system has been defined.This mixedsystemshows no limitationsand. thus, can be applied to single castingsor multiple-printcastings (withsymmetricalor nonsymmetricalDlacemen[ ).

Also.one or more gates (whether evenly spaced or not) percasting. for top or bottom orside pourn-q, can be chosen at willanddepending on the specific needs. It ensures, also, a more thansatisfactoryseparation ofslag in the top runner. ensuring at the sametime a nearly simultaneousand nonturbulentfillingin all levels.

Also. thepouring rate remains constant during moldfillingdespite casting positioningin the pattern plate. ln this way. reiectiondue to surface defects (because of sand. s lag, metal splash ing orcoldmetal)can be minimized and castings withhigh standards of surfacequalitycan be produced.

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Ref. : ? CASEHISTORYDate : 03-24-1992

2.Nmi,er of castings.. -.....:? 15I.Nmber of levefs ...:? 36. Spacing between levels ' .m: ? 100

lO.Expected casting Yiel.d, . .%:?

Ref. : CASE HISTORYDate : 03-26 1992

2.Numberof castings..'.'...: 154.Nrmberof levels.',....'..: 36. Spacing between leveLs ' .m: 100

lO.Expected yield. ,..%: 43

Expected poured weight. .'ket 20.93T rilnhai mm' 15 t 30 - 72 * ZuPri-mary gates...m: I * 29 - 4 * 15Vert.runn. m: 13 * 13 / 5 i 9 x 9 /Choke vert.runn. m2: 65 - 32/Iev, 7Choke vert.runn, mm2: 27 - 3/lev.2

A case historyhas been used to illustratethe steps for designingand also to show the results obtained.Dimensioningo1- the entiregatingsystem can appear tedious to a certain extent. For this reasona specific softwarehas been developed.Its practicalapplicationtothe case history has been discussed.

The data obtained can be used in conjunctionwithCADsofiwareto producc the detailed drawings for the pattern shop. Someapplicationshave been illustrated.Thisapproach does not demandspecial skillsor costly hardwareand for thcse reasons is, no doubt,

convenientfor foundriespossessing verticalparted moldinglines.ACKNOWLEDGMENT

The author is indebtedto Peraro Foundry lbr permissionto publishthe case history.

REFERENCES

L J B. Caine: "Two[nterrelated Factors Influencing NonmetallicsanclMisruns in lron andSteel Castings.''AFS Ttunsattirttts, vol 71.pp 193-202 ( | 963).

2. S. Karsay: "Ductilelron 111." QIT-Fer et Titane. Inc.. Sorel (Canada)(l9Ul)o43.

Press Return to try agarn

Fig 9a Hard copy resultingfrom data entered (top half) and castng yieldevaluaton (bottomhalf) with"Mixto-Press"referredto in the case hstory.

To modify enter the relative nmber. N. 12,13 e 14 reserved to time,primary gates thickness and frictj.on factor:?

Fig 9b Typical hardcopywithdata+resultsusing "Mixto-Press"referred to in the case hstory(cs: cross section, lev: level, verl:veftcal, runn: runner)

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ffilEd*q.

I

Fig 10 The CAD technique can be usedn conjunction with"Mixto-Press"to producedetailed drawings for pattern plate constructon. ln thiscase, veftical runnersare bent to increase the salety distance"d".(Photo couftesyof StudioCausin, Spresiano, ltaly.)

AFS Transactions 767

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Disamatic Gating