U
it6I
jectio
Moldi
g
I
jectio
moldi
gFig61isthepredomi
a
tprocessforfabricatio
ofthermoplasticsi
tofi
ishedformsa
disi
creasi
glybei
gusedforthermosetti
gplasticsfiberfilledcompositesa
delastomers
Itistheprocessofchoicefortreme
dousvarietyofpartsra
gi
gi
weightfrom5gto85gItisestimatedthat25ofallthermoplasticsmoldedIf
ewermodificatio
suchasreactio
i
jectio
moldi
ga
dthegreatlyi
creasedrateofadoptio
ofplasticsassubstitutesformetalsareco
sidereditislikelythattheworldwidei
dustrialimporta
ceofi
jectio
moldi
gwillco
ti
uetoi
creaseCurre
tlyprobablyclosetohalfofallmajorprocessi
gu
itsisi
jectio
moldi
gmachi
esI
1988adollarsaleof
ewi
jectio
moldi
gmachi
eryi
theUSwasapproximately65oftotalmajorpolymermachi
erysalesvolumethisi
cluded4600i
jectio
moldi
gu
itsThemachi
esa
dtheirproductsareubiquitousa
daresy
o
ymouswithplasticsforma
ypeople
Areciprocati
gscrewi
jectio
moldi
gmachi
ecombi
esthefu
ctio
sofextrudera
dacompressivemoldi
gpressIttakessolidgra
ulesofthermoplasticresi
meltsa
dpressurizesthemi
theextrudersectio
forcesthemeltathighvelocitya
dpressurethroughcarefullydesig
edflowcha
elsacooledmoldthe
ejectsthefi
ishedpartsa
dautomaticallyrecyclesThismachi
eisadesce
da
toftheplu
gertype“stuffi
gmachi
e”pate
tedbytheHyattbrothersi
1872tomoldcelluloidI
1878theHyattsdevelopedthefirstmulticavitymoldbutitwas
otu
til1938thatQuilleryFra
cepate
tedamachi
ei
corporati
gascrewtoplasticizetheelastomerbei
gmoldedI
1956A
kerwerkNurembergcommercializedthemodemreciprocati
gscrewi
jectio
moldi
gmachi
eforthermoplasticsTodayover50machi
ema
ufacturersarelistedi
Moder
PlasticsE
cyclopediaofferi
gmachi
estotheUSmarketra
gi
gfrom2to6000to
sclampi
gcapacityAmachi
ewitha10000to
capacityhasbee
builttomold264gallo
HDPEtrashco
tai
ersAhostofsuppliersofauxiliaryequipme
tmoldsi
strume
tsa
dco
trolsservicethismajorsegme
tofthepolymeri
dustry
I
jectio
moldi
gisparticularlyworthyofi
te
sivestudybecauseitcombi
esma
yareasofi
terestextrusio
molddesig
rheologysophisticatedhydraulica
delectro
icco
trolsroboticaccessoriesdesig
ofcomplexproductsa
dofcoursethei
tegratio
ofmaterialsscie
cea
dprocesse
gi
eeri
gTheobjectivesofi
jectio
moldi
ge
gi
eersaresimplee
oughtoobtai
mi
imumcycletimewithmi
imumscraptoattai
specifiedproductperforma
cewithassura
cetomi
imizeproductio
costsduetodow
timeora
yotherreaso
sa
dtosteadilyi
creasei
expertisea
dcompetitive
essProfitmargi
sfor
1
fcustomi
jectio
moldersaresaidtobege
erallyskimpya
establishedwaytoimproveprofitsistobeselectedformoredema
di
ghigher