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ProcessandProductDevelopment
ValveTappetColdforgingProcess
AbdullahAnsari
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INDEX Introduction
NatureofProblem
ExistingBlank&ForgingDieAnalysis
ColdForgingStandard
ExistingD2/d2 &l/dRatios
CorrectiveActions
Recalculations,ResultsOfRecalculations
Trials&Decisions
PreviousProcess&RevisedProcess
ResultswithRevisedTooling&Conlusion
SupportDuringDevelopment
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INTRODUCTION
The problem of head offsetting while cold forging of item R
70813 is observedin since new product development.
To avoid the same several corrective actions [short method] were
initiated suchas using flat ejector etc. but effectiveness of the
actions taken was not 100%satisfactory. The results were not
consistent.
After all above it is concluded to analyze and redesign of cold
forging tooling &process.
While analyzing the same whatever the calculations, observations
and theactions taken by undersigned are recorded here, which will
be one guide line toattend this kind of problems in future.
A.T.ANASRIDate:22.08.2000
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NatureofProblem
(TappetR70813)Whilecoldforging1st
stageHeadDiameterofTappetgettingmoreoffsets¬gettingcontrolledafter
severaladjustments.
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ExistingBlank&ForgingDieanalysis
.SizeofColdforgingblank:TotalLength=85mmOuterdiameter(d)=12.5mm
.Sizeofcoldforgedpart:Headdiameter(D)=30mmHeadthickness=5.5mmTotallength=61mmODofstem=12.8&12.6mm
.SizeofColdforgingDie:Lengthofdie=90mmLengthofblankoutsidethedie(l)=30mm
(Fromflatface)
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Coldforgingstandard
Coldforgingstandardstatesthat:D2/d2
andl/dshouldnotexceed3.Where2isideal.
InourcaseD=30mmd=12.5mml=30mm
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D2/d2 =302/12.52 =5.76l/d=30/12.5=2.40
ByabovecalculationsitisnoticedthatvalueD2/d2 is
exceeding thestandardandl/disalmostinrange.
Sowemayconcludethataboveexceedingvalue is
affectingtoforgedheaddiameteroffsetting.
InlightofColdForgingStandardExistingD2/d2&l/dratios
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Whattodonow???
Correctiveactionplanned :Recalculate the die design as per
coldforging standard. And manufacture thecold forging die as per
new calculateddimensions.
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RecalculationsasperColdforgingstandard
D2/d2 = 2 ( as per standard )Hence D2/12.52 = 2D2 = 2 x
12.52
D = 17.67mm.l of D will be 17.67x17.67x l x /4 = 12.5x12.5x30x
/4
l = 15.01mm
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WhatRecalculationsIndicating!!!
Recalculations indicating that the forging is not possible in
one operation& it will need double operation. For second
operation stepped blank willbe required, while first operation
stepped blank will be produced.
Forpreparingsteppedblankseparatedieisrequired
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Trials.
Fortrialssteppedblankispreparedbymachining.Whiletrialsformingpunchisused.
Trialsaretakenwithsteppedblankon22.08.2000Resultsfoundsatisfactoryinallaspects.Head
offsetting is very low & will not create anydefect while head
turning.
Dimensions are found consistent.Trials are successful.
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WayForward.
Basedonsuccessfultrials,diedesignedforfirstoperationforpreparingthesteppedblank(coldforging1st
operation).
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#PREVIOUSPROCESS
Fig.Showsthe
blankreadyfor
forgingofR708
13tappet.
85
12.5
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1 PREVIOUSPROCESS
Fig.Showstheforgingdrawingof
R70813tappet.
Previouslythiswascreatedinsingle
setting.
30 12.8
5
40
12.6
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#REVISEDPROCESS
Fig.Showsthe
blankreadyfor
producing
steppedblank
forforgingof
R70813tappet.
85
12.5
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1 REVISEDPROCESS
Fig.Showsthe
steppedblank
readyforfinish
forgingofR70813
tappet.
12.6 12.5
40
17.7
15
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30 12.8
5
40
12.6
2 REVISEDPROCESS
Fig.ShowsthefinishforgingofR70813
tappet.
Nowitiscreatedinsecondstagefrom
steppedblank.
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DiedrawingforsteppedBlank
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Resultswithrevisedtooling.
Implemented the new tooling & monitored for 1000nos forcold
forging 1st & 2nd operation.
Noproblemwhilepreparingsteppedblank.I.e.1stoperation.
Noproblemofheadformingwhile2nd
operation.Improvedconsistencyindimensionswhilecoldforging2nd
stage.
Settingtimeforcoldforgingisreduced.Minimizesrejectionatcoldforgingdrastically.Hencereductioninwastage.
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FINALCONCLUSION.
The newly designed tooling is OK & Proven
for production.05.11.2000
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Mr.VRamgopalMr.M.GANAPATHY
ForGivingAOpportunityToWorkOnSuchASpecialTask.
Mr.S.C.SALVI&Mr.P.S.KULKARNITeammembers
Acknowledgements
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ThankYou
[email protected]
