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Injection Molding – defects, causes, remedies
Tips for defect-free extrusion of polycarbonates and their blends
1 Fault category: Part dimensions
2 Fault category: Ejection characteristics
3 Fault category: Colors
4 Fault category: Specks
5 Fault category: Surface irregularities
6 Fault category: Processing
7 Fault category: Warping
8 Fault category: Gloss
9 Fault category: Mechanical properties
10 Fault category: Streaking
4
9
17
25
26
31
32
33
41
43
Various problems can arise when extruding polycarbon-ates and their blends. We have compiled an extensive list of possible defects, explained their causes and described preventive measures. To help you fi nd them more easily, we have divided the defects into groups, such as “Defects caused by moisture” or “Defects commonly associated with blown fi lms”. Please do not hesitate to contact us if this list does not help you solve your problem.
We would be grateful for any hints, suggestions and illustrations you could submit to make this catalog of de-fects more complete.
4
Part
fail
s to
fi ll
pro
perl
yD
escr
ipti
on: I
ncom
plet
e fi l
ling
of th
e pa
rt, g
ener
ally
at t
he e
nds
of fl
ow p
aths
or
at t
hin
sect
ions
1 F
ault
cat
egor
y: P
art d
imen
sion
s
Caus
es:
Rem
edia
l act
ions
:
Uns
uita
ble
proc
essi
ng p
aram
eter
sO
ptim
ize
proc
essi
ng p
aram
eter
s. In
crea
se m
elt a
nd m
old
tem
pera
ture
. Inc
reas
e in
ject
ion
spee
d. S
witc
h to
hol
ding
pr
essu
re a
t a la
ter s
tage
Exce
ssiv
e lo
ss o
f pre
ssur
e in
gat
ing
syst
em (i
nclu
ding
hot
ru
nner
). G
ate
and
runn
er c
ross
sec
tions
too
smal
l. Ex
cess
ive
loss
of p
ress
ure
in h
ot ru
nner
. Exc
essi
ve lo
ss o
f pre
ssur
e in
sh
ut-o
ff no
zzle
sys
tem
Redu
ce p
ress
ure
loss
es in
the
gatin
g sy
stem
. Enl
arge
gat
e an
d ru
nner
cro
ss s
ectio
ns. C
heck
cro
ss s
ectio
n of
hot
runn
er,
optim
ize
torp
edo
at n
ozzl
e po
int.
Use
the
mac
hine
with
out
shut
-off
nozz
le
Insu
ffi ci
ent s
ectio
n th
ickn
ess
Incr
ease
sec
tion
thic
knes
s
5
Vari
atio
ns in
wei
ght
Des
crip
tion
: Wei
ght a
nd d
imen
sion
s of
par
ts v
ary
grea
tly
Caus
es:
Rem
edia
l act
ions
:
Plas
ticiz
ing
unit
wor
nEx
amin
e pl
astic
izin
g un
it an
d pa
rtic
ular
ly n
on-r
etur
n va
lve
for w
ear
Fluc
tuat
ions
in te
mpe
ratu
re o
f mel
t and
mol
dCh
eck
tem
pera
ture
con
trol
and
hea
ting
circ
uits
of t
he
plas
ticiz
ing
unit
Mat
eria
l not
thor
ough
ly d
ried
Chec
k dr
ying
pro
cess
Varia
tions
in m
eter
ing
stro
ke o
r mel
t cus
hion
Chec
k in
ject
ion
stro
ke a
nd m
eter
ing
stro
ke o
f the
mac
hine
clam
ping
forc
e to
o lo
wSe
t cla
mpi
ng fo
rce
high
er o
r use
a m
achi
ne w
ith a
hig
her
clam
ping
forc
e
6
Inco
rrec
t dim
ensi
ons
Des
crip
tion
: Mol
ding
fails
to a
ttai
n re
quir
ed d
imen
sion
s
Caus
es:
Rem
edia
l act
ions
:
Exce
ssiv
e m
oist
ure
in m
ater
ial
Chec
k dr
ynes
s of
mat
eria
l
Shrin
kage
inco
rrec
tly p
redi
cted
Chec
k sh
rinka
ge c
alcu
latio
ns w
ith th
e ai
d of
raw
mat
eria
l m
anuf
actu
rer’s
dat
a or
com
para
ble
mol
ds
War
ping
cau
sed
by p
oor p
art d
esig
n or
gat
e lo
catio
nCh
eck
part
and
rede
sign
for m
inim
um w
arpa
ge.
Alte
r pos
ition
of g
ate
to e
nsur
e re
gula
r mel
t orie
ntat
ion
Mac
hine
and
mol
d no
t in
ther
mal
equ
ilibr
ium
Ch
eck
tem
pera
ture
con
trol
of m
achi
ne a
nd m
old
for t
herm
al
fl uct
uatio
ns
Ist
Soll
7
Flas
hD
escr
ipti
on: T
hin
web
of m
ater
ial f
orce
d in
to c
revi
ces
betw
een
mat
ing
mol
d su
rfac
es d
urin
g m
oldi
ng a
nd re
mai
ning
att
ache
d to
mol
ded
part
Caus
es:
Rem
edia
l act
ions
:
Gap
bet
wee
n m
old
halv
es to
o w
ide.
Loc
king
forc
e to
o sm
all.
Inad
equa
te m
old
rigid
ity. M
old
seal
ing
face
s w
orn
Chec
k ga
p w
idth
s. In
crea
se lo
ckin
g fo
rce.
In
crea
se m
old
rigid
ity. R
efi n
ish
mol
d se
alin
g fa
ces
Proc
essi
ng p
aram
eter
s no
t opt
imiz
edO
ptim
ize
proc
essi
ng p
aram
eter
s. R
educ
e in
ject
ion
spee
d or
m
elt t
empe
ratu
re. S
witc
h fr
om in
ject
ion
to h
oldi
ng p
ress
ure
earli
er, o
r red
uce
hold
ing
pres
sure
Mat
eria
l too
moi
st, t
hus
visc
osity
redu
ced
Chec
k dr
ying
of m
ater
ial
8
Vari
atio
ns in
sec
tion
thic
knes
s (t
arge
t/ac
tual
)D
escr
ipti
on: P
art t
hick
ness
doe
s no
t mat
ch u
p to
requ
irem
ents
, or v
arie
s a
grea
t dea
l and
lies
out
side
tole
ranc
e ra
nge
Caus
es:
Rem
edia
l act
ions
:
Inad
equa
te m
old
rigid
ityCh
eck
rigid
ity o
f mol
d an
d st
reng
then
it if
nec
essa
ry
Failu
re to
allo
w fo
r shr
inka
ge, m
old
dim
ensi
ons
inco
rrec
tCh
eck
mol
d di
men
sion
s an
d co
mpa
re w
ith ra
w m
ater
ial
man
ufac
ture
r’s d
ata
on s
hrin
kage
Cavi
ty p
ress
ure
too
high
or l
ocki
ng fo
rce
too
low
Redu
ce c
avity
pre
ssur
e by
sw
itchi
ng fr
om in
ject
ion
to h
old-
ing
pres
sure
at a
n ea
rlie
r sta
ge, r
educ
ing
hold
ing
pres
sure
an
d in
crea
sing
lock
ing
forc
e
Mol
d ce
nter
ing
mec
hani
sm d
efec
tive
or w
orn
Chec
k m
old
cent
erin
g/gu
ide
mec
hani
sm a
nd re
plac
e if
nece
ssar
y.
9
2 F
ault
cat
egor
y: E
ject
ion
char
acte
rist
ics
Sti
ckin
g sp
rue
Des
crip
tion
: Spr
ue is
con
stri
cted
and
/or l
eft i
n th
e sp
rue
bush
or i
n th
e co
ld
runn
er
Caus
es:
Rem
edia
l act
ions
:
Proc
essi
ng p
aram
eter
s no
t ide
al (e
.g. t
imin
g of
cha
ngeo
ver
from
inje
ctio
n to
hol
ding
pre
ssur
e, le
vel o
f hol
ding
pre
ssur
e)
Opt
imiz
e pr
oces
sing
par
amet
ers.
Red
uce
cavi
ty p
ress
ure
by
redu
cing
hol
ding
pre
ssur
e an
d sw
itchi
ng to
it e
arlie
r. Ch
eck,
an
d if
nece
ssar
y, e
xten
d co
olin
g tim
e
Noz
zle
radi
us o
r ape
rtur
e to
o la
rge
Redu
ce n
ozzl
e ra
dius
or a
pert
ure
Dra
ft a
ngle
s to
o sm
all o
r pol
ishi
ng in
adeq
uate
Chec
k co
mpo
nent
s lik
e in
ject
ion
nozz
le, c
old
runn
er a
nd
gate
for u
nder
cuts
and
pol
ishi
ng e
ffect
iven
ess,
and
re-
mac
hine
in d
emol
ding
dire
ctio
n if
nece
ssar
y. O
ptim
ize
draf
t an
gles
and
pol
ish
if ne
cess
ary
Mac
hine
noz
zle
and
spru
e bu
sh a
re n
ot fl
ush
Corr
ect p
ositi
on
10
Ejec
tor
mar
ksD
escr
ipti
on: V
isib
le e
ject
or m
arks
on
part
sur
face
Caus
es:
Rem
edia
l act
ions
:
Cavi
ty p
ress
ure
too
high
Opt
imiz
e pr
oces
sing
par
amet
ers.
Red
uce
hold
ing
pres
sure
an
d sw
itch
to it
ear
lier.
Mol
d st
iffne
ss n
ot s
uffi c
ient
Impr
ove
mol
d st
iffne
ss
Cool
ing
time
too
shor
t or m
old
cavi
ty te
mpe
ratu
re to
o hi
gh
loca
llyO
ptim
ize
cool
ing
and/
or m
old
tem
pera
ture
Mol
d de
sign
unf
avor
able
. Und
ercu
ts to
o ex
trem
e, d
raft
an
gle
too
low
Opt
imiz
e m
old
desi
gn. R
educ
e un
derc
uts,
impr
ove
draf
t an
gles
Mol
d po
lishi
ng in
adeq
uate
. Pos
ition
s of
eje
ctor
s un
favo
rabl
e or
eje
ctor
sur
face
too
smal
lO
ptim
ize
polis
hing
. Che
ck e
ject
or p
ositi
ons
and/
or in
crea
se
ejec
tor s
urfa
ce
11
Mol
d op
enin
g no
ise
Des
crip
tion
: Mol
d m
akes
a lo
t of n
oise
whe
n op
ened
Caus
es:
Rem
edia
l act
ions
:
Dra
ft a
ngle
s to
o sm
all
Chec
k m
old
polis
hing
eff
ectiv
enes
s an
d dr
aft a
ngle
s an
d re
-m
achi
ne if
nec
essa
ry. U
se a
sui
tabl
e m
old
rele
ase
agen
t
Mol
d ce
nter
ing
devi
ce d
efec
tive
or w
orn
Impr
ove
mol
d ce
nter
ing
Cavi
ty p
ress
ure
too
high
Redu
ce c
avity
pre
ssur
e. S
witc
h fr
om in
ject
ion
to h
oldi
ng
pres
sure
ear
lier.
Redu
ce h
oldi
ng p
ress
ure
Inad
equa
te m
old
rigid
itySt
reng
then
mol
d
Diff
eren
ce in
tem
pera
ture
of m
old
halv
es to
o la
rge
Diff
eren
ces
in te
mpe
ratu
re b
etw
een
slid
es a
nd m
old
too
grea
tCh
eck
tem
pera
ture
s an
d eq
ualiz
e
12
Part
rem
ains
in m
old
cavi
ty –
Cau
ses
Des
crip
tion
: Par
t rem
ains
in m
old
cavi
ty
Caus
es:
Rem
edia
l act
ions
:
Mol
d ov
erlo
aded
Redu
ce in
ject
ion
spee
d an
d ho
ldin
g pr
essu
re, a
nd s
witc
h to
ho
ldin
g pr
essu
re a
t an
earl
ier s
tage
Und
ercu
ts to
o pr
onou
nced
, dra
ft a
ngle
s to
o sm
all
Redu
ce s
ize
of u
nder
cuts
and
impr
ove
draf
t ang
les
Mol
d no
t suf
fi cie
ntly
pol
ishe
d at
ribs
and
bos
ses
Polis
h ca
vity
sur
face
in d
irect
ion
of d
emol
ding
Vacu
um b
etw
een
mol
d su
rfac
e an
d pa
rtO
ptim
ize
mol
d ve
ntin
g
Prem
atur
e de
mol
d: p
art s
ticks
or i
s st
ill to
o so
ftIn
crea
se c
oolin
g tim
e, re
duce
mol
d te
mpe
ratu
re
Ejec
tor p
ins
poor
ly p
ositi
oned
or t
oo fe
w in
num
ber
Use
mor
e ej
ecto
r pin
s or
opt
imiz
e th
eir p
ositi
on
13
Caus
es:
Rem
edia
l act
ions
:
Mol
d ov
erlo
aded
Redu
ce in
ject
ion
spee
d an
d ho
ldin
g pr
essu
re, a
nd s
witc
h to
ho
ldin
g pr
essu
re a
t an
earl
ier s
tage
Und
ercu
ts to
o pr
onou
nced
, dra
ft a
ngle
s to
o sm
all
Redu
ce s
ize
of u
nder
cuts
and
impr
ove
draf
t ang
les
Mol
d no
t suf
fi cie
ntly
pol
ishe
d at
ribs
and
bos
ses
Polis
h ca
vity
sur
face
in d
irect
ion
of d
emol
ding
Vacu
um b
etw
een
mol
d su
rfac
e an
d pa
rtO
ptim
ize
mol
d ve
ntin
g
Prem
atur
e de
mol
d: p
art s
ticks
or i
s st
ill to
o so
ftIn
crea
se c
oolin
g tim
e, re
duce
mol
d te
mpe
ratu
re
Ejec
tor p
ins
poor
ly p
ositi
oned
or t
oo fe
w in
num
ber
Use
mor
e ej
ecto
r pin
s or
opt
imiz
e th
eir p
ositi
on
Def
orm
atio
n of
par
t – C
ause
sD
escr
ipti
on: P
art d
efor
med
dur
ing
dem
oldi
ng
Caus
es:
Des
crip
tion
:
Cavi
ty p
ress
ure
too
high
Opt
imiz
e in
ject
ion
spee
d. R
educ
e ho
ldin
g pr
essu
re.
Switc
h to
hol
ding
pre
ssur
e at
an
earli
er s
tage
Inad
equa
te m
old
rigid
itySt
reng
then
mol
d
Cool
ing
time
too
shor
t or m
old
tem
pera
ture
too
high
in p
lace
sO
ptim
ize
cool
ing/
mol
d te
mpe
ratu
re c
ontr
ol
Poor
mol
d de
sign
. Und
ercu
ts to
o pr
onou
nced
, dra
ft a
ngle
s to
o sm
all
Opt
imiz
e m
old
desi
gn. R
educ
e un
derc
uts
and
optim
ze d
raft
an
gles
Mol
d no
t suf
fi cie
ntly
pol
ishe
d. E
ject
or p
ins
poor
ly p
ositi
oned
or
sur
face
are
a to
o sm
all
Polis
h m
old
surfa
ce in
dire
ctio
n of
dem
oldi
ng, c
hoos
e a
suita
ble
surfa
ce c
oatin
g or
dep
th o
f tex
ture
. Opt
imiz
e po
sitio
n an
d si
ze o
f ej
ecto
rs (i
n pa
rtic
ular
, loc
ate
near
cor
ners
or u
nder
ribs
or b
osse
s)
14
Part
rup
ture
s du
ring
dem
oldi
ng –
Cau
ses
Des
crip
tion
: Par
t dam
aged
dur
ing
dem
oldi
ng
Caus
es:
Rem
edia
l act
ions
:
Cavi
ty p
ress
ure
too
high
Opt
imiz
e in
ject
ion
spee
d. R
educ
e ho
ldin
g pr
essu
re.
Switc
h to
h ol
ding
pre
ssur
e at
an
earl
ier s
tage
Inad
equa
te m
old
rigid
itySt
reng
then
mol
d
Cool
ing
time
too
long
or m
old
tem
p to
o lo
w in
pla
ces
Opt
imiz
e co
olin
g/m
old
tem
pera
ture
con
trol
Poor
mol
d de
sign
. Und
ercu
ts to
o pr
onou
nced
, dr
aft a
ngle
s to
o sm
all
Opt
imiz
e m
old
desi
gn. R
educ
e si
ze o
f und
ercu
ts a
nd o
ptim
ize
draf
t ang
les
15
Part
rup
ture
s du
ring
dem
oldi
ng –
Cau
ses
Caus
es:
Rem
edia
l act
ions
:
Mol
d no
t suf
fi cie
ntly
pol
ishe
d. E
ject
or p
ins
poor
ly
posi
tione
d or
sur
face
are
a to
o sm
all
Polis
h ca
vity
sur
face
in d
irect
ion
of d
emol
ding
, cho
ose
a su
itabl
e su
rfac
e co
atin
g or
dep
th o
f tex
ture
. Opt
imiz
e po
sitio
n an
d si
ze o
f ej
ecto
r pin
s (it
is p
artic
ular
ly im
port
ant t
o lo
cate
them
nea
r cor
ners
, un
der r
ibs
and
boss
es)
Mat
eria
l not
ade
quat
ely
drie
d, re
side
nce
time
too
long
Chec
k dr
ying
of m
ater
ial,
resi
denc
e tim
e an
d m
elt t
empe
ratu
re
Not
ch e
ffect
due
to e
xces
sive
ly s
harp
-edg
ed tr
ansi
-tio
nsRo
und
off,
if po
ssib
le
16
Mol
d w
ill n
ot o
pen
Des
crip
tion
: Eve
n w
hen
the
max
imum
per
mis
sibl
e m
old
open
ing
forc
e is
ap
plie
d, th
e m
old
halv
es c
anno
t be
sepa
rate
d
Caus
es:
Rem
edia
l act
ions
:
Cavi
ty p
ress
ure
too
high
Redu
ce c
avity
pre
ssur
e. S
witc
h fr
om in
ject
ion
to h
oldi
ng
pres
sure
soo
ner.
Redu
ce h
oldi
ng p
ress
ure.
Incr
ease
mel
t te
mpe
ratu
re w
ithin
acc
epta
ble
limits
Inad
equa
te m
old
rigid
itySt
reng
then
mol
d
Slid
e co
ntro
l not
wor
king
Chec
k po
sitio
n of
slid
es
Not
e: O
pen
mol
d: U
se c
old
wat
er to
redu
ce te
mpe
ratu
re o
f mol
d to
room
tem
pera
ture
, fi t
addi
tiona
l hyd
raul
ic ra
ms
betw
een
ma-
chin
e pl
aten
s to
hel
p op
en m
old.
If n
eces
sary
, rai
se m
old
tem
-pe
ratu
re a
bove
gla
ss tr
ansi
tion
tem
pera
ture
, pul
l mol
d ap
art
17
Dee
per
colo
r at
wel
d li
nes
Des
crip
tion
: Fou
nd a
t wel
d lin
es o
r nea
r fas
ter o
r slo
wer
-mov
ing
fl ow
fron
ts fe
d fr
om n
eigh
bori
ng m
elt s
trea
ms
Caus
es:
Rem
edia
l act
ions
:
Pigm
ent s
epar
atio
n or
ligh
t ref
ract
ion
effe
ct c
ause
d by
un
favo
rabl
e fl o
w a
t wel
d lin
esVa
ry fl
ow fr
ont v
eloc
ity
Ther
mal
ove
rloa
ding
of t
he m
elt l
eadi
ng to
dis
colo
ratio
n at
w
eld
lines
Redu
ce th
erm
al lo
ad o
n th
e m
elt
Oxi
datio
n du
e to
insu
ffi ci
ent v
entin
gIm
prov
e ve
ntin
g, p
ossi
bly
by re
loca
ting
the
wel
d lin
e
Not
e: T
ends
to o
ccur
on
light
, brig
ht c
olor
s su
ch a
s w
hite
, bl
ue, g
reen
and
ora
nge
3 F
ault
cat
egor
y: C
olor
s
Caus
es:
Rem
edia
l act
ions
:
Cavi
ty p
ress
ure
too
high
Redu
ce c
avity
pre
ssur
e. S
witc
h fr
om in
ject
ion
to h
oldi
ng
pres
sure
soo
ner.
Redu
ce h
oldi
ng p
ress
ure.
Incr
ease
mel
t te
mpe
ratu
re w
ithin
acc
epta
ble
limits
Inad
equa
te m
old
rigid
itySt
reng
then
mol
d
Slid
e co
ntro
l not
wor
king
Chec
k po
sitio
n of
slid
es
Not
e: O
pen
mol
d: U
se c
old
wat
er to
redu
ce te
mpe
ratu
re o
f mol
d to
room
tem
pera
ture
, fi t
addi
tiona
l hyd
raul
ic ra
ms
betw
een
ma-
chin
e pl
aten
s to
hel
p op
en m
old.
If n
eces
sary
, rai
se m
old
tem
-pe
ratu
re a
bove
gla
ss tr
ansi
tion
tem
pera
ture
, pul
l mol
d ap
art
18
Cons
iste
nt d
isco
lora
tion
, col
or d
evia
tion
sD
escr
ipti
on: C
onsi
sten
t dev
iati
on fr
om th
e ba
sic
colo
r, pa
rtic
ular
ly w
ith
light
col
ors
Caus
es:
Rem
edia
l act
ions
:
Mel
t tem
pera
ture
too
high
Chec
k m
elt t
empe
ratu
re a
nd re
duce
it if
nec
essa
ry
Resi
denc
e tim
e to
o lo
ng, b
ecau
se p
last
iciz
ing
unit
not
wor
king
at f
ull c
apac
ityU
se a
sm
alle
r pla
stic
izin
g un
it
Uns
uita
ble
mas
terb
atch
Use
a s
uita
ble
mas
terb
atch
Prod
uctio
n in
terr
upte
d w
ithou
t red
ucin
g te
mpe
ratu
reSe
e no
tes
on p
rodu
ctio
n st
oppa
ges
19
Colo
r in
cons
iste
ncie
sD
escr
ipti
on: C
olor
inco
nsis
tenc
ies
Caus
es:
Rem
edia
l act
ions
:
Mat
eria
l not
suf
fi cie
ntly
hom
ogen
ized
Incr
ease
bac
k pr
essu
re, r
educ
e sc
rew
spe
ed
Inje
ctio
n an
d sc
rew
spe
ed to
o hi
ghRe
duce
inje
ctio
n an
d sc
rew
spe
ed
Gat
e to
o na
rrow
Enla
rge
gate
Resi
denc
e tim
e to
o lo
ngRe
duce
resi
denc
e tim
e by
usi
ng a
sm
alle
r pla
stic
izin
g un
it
20
Rin
gs a
roun
d th
e ga
teD
escr
ipti
on: M
att r
ings
alig
ned
conc
entr
ical
ly a
roun
d th
e ga
te
Caus
es:
Rem
edia
l act
ions
:
Stag
natio
n of
mel
t fl o
w in
the
mol
d, m
elt t
empe
ratu
re
too
low
Try
to m
aint
ain
an e
ven
mel
t fl o
w, r
aise
mel
t tem
pera
ture
Stag
natio
n of
mel
t fl o
w in
the
mol
d, m
old
tem
pera
ture
too
low
Try
to m
aint
ain
an e
ven
mel
t fl o
w, r
aise
mol
d te
mpe
ratu
re
Inje
ctio
n ra
te to
o lo
wTr
y to
mai
ntai
n an
eve
n m
elt fl
ow
, inc
reas
e in
ject
ion
rate
21
Bla
ck d
isco
lora
tion
, bur
n m
arks
, per
iodi
c di
scol
orat
ion
Des
crip
tion
: Bro
wn
to b
lack
, irr
egul
ar a
nd lo
cally
var
iabl
e di
scol
orat
ion
of th
e m
olde
d pa
rt
Caus
es:
Rem
edia
l act
ions
:
Uns
uita
ble
desi
gn o
f cha
nges
in c
ross
sec
tion
and
bend
s in
th
e ho
t run
ner,
or fa
ulty
sea
ling
face
s le
adin
g to
dea
d sp
ots
whe
re th
e m
ater
ial b
ecom
es c
harr
ed. D
ead
spot
s oc
curr
ing
at s
ealin
g fa
ces,
cha
nges
in c
ross
sec
tion
and
bend
s in
the
hot r
unne
r
Chec
k an
d/or
rede
sign
the
rele
vant
com
pone
nts
and
seal
ing
surf
aces
. Elim
inat
e de
ad s
pots
. Che
ck th
e pr
essu
re
relie
f hol
es fo
r the
nee
dle
shut
-off
mec
hani
sm. I
nspe
ct s
eal-
ing
face
s
Wea
r on
the
scre
w, t
he n
on-r
etur
n va
lve
or th
e cy
linde
rCh
eck
the
scre
w, t
he n
on-r
etur
n va
lve
and
the
cylin
der f
or
wea
r
22
Bla
cken
ing,
Die
sel e
ffec
tD
escr
ipti
on: C
once
ntra
ted
blac
keni
ng a
t wel
d lin
es, e
.g. n
ear r
ibs
or b
osse
s,
or in
cor
ners
at t
he e
nd o
f fl o
w p
aths
Caus
es:
Rem
edia
l act
ions
:
Entr
appe
d, c
ompr
esse
d ai
r in
the
mol
d le
adin
g to
sco
rchi
ng
Opt
imiz
e m
old
vent
ing,
par
ticul
arly
whe
re fl
ow fr
onts
m
eet a
nd a
t the
end
of fl
ow
pat
hs. C
orre
ct fl
ow fr
ont p
rofi l
e by
adj
ustin
g se
ctio
n th
ickn
ess,
gat
e lo
catio
n or
usi
ng fl
ow
lead
ers.
Che
ck v
entin
g ch
anne
ls. R
educ
e m
old
lock
ing
forc
e.
Evac
uate
mol
d
Not
e: In
add
ition
to o
ptic
al d
egra
datio
n of
the
mol
ded
part
, th
is fa
ult c
an a
lso
dam
age
the
mol
d th
roug
h co
rros
ion
23
Str
ess
whi
teni
ngD
escr
ipti
on: A
reas
of l
ight
er c
olor
com
bine
d w
ith
a ve
lvet
y m
att p
art s
urfa
ce
Caus
es:
Rem
edia
l act
ions
:
Ove
rstr
etch
ing
of th
e po
lym
er m
atrix
. Exc
essi
ve m
echa
nica
l st
ress
dur
ing
ejec
tion.
Poo
rly
posi
tione
d ej
ecto
r pin
s an
d dr
aft a
ngle
s to
o sm
all
Redu
ce m
echn
ical
str
ess
durin
g ej
ectio
n.Co
rrec
t pos
ition
s of
eje
ctor
s, e
.g. p
ositi
on e
ject
ors
at s
tres
s w
hite
ning
line
s
Exce
ssiv
e st
ress
in s
ervi
ceLo
wer
str
esse
s in
ser
vice
Cavi
ty p
ress
ure
too
high
. Ina
dequ
ate
mol
d rig
idity
Low
er c
avity
pre
ssur
e. S
tren
gthe
n m
old
rigid
ity
Not
e: F
ault
mos
tly o
ccur
s w
ith th
erm
opla
stic
s co
ntai
ning
ru
bber
24
Clou
dine
ss, g
rey
stre
aks
Des
crip
tion
: Dar
k, c
loud
y ar
eas
on p
art s
urfa
ce
Caus
es:
Rem
edia
l act
ions
:
Plas
ticiz
ing
unit
cont
amin
ated
Clea
n pl
astic
izin
g un
it. R
educ
e sc
rew
spe
ed
Wea
r on
the
plas
ticiz
ing
unit
Repl
ace
com
plet
e pl
astic
izin
g un
it or
indi
vidu
al c
ompo
nent
s.
Use
a c
orro
sion
- and
abr
asio
n-re
sist
ant p
last
iciz
ing
unit
Mel
t loa
d to
o hi
gh
Opt
imiz
e cy
linde
r tem
pera
ture
, circ
umfe
rent
ial s
peed
of t
he
scre
w, b
ack
pres
sure
25
Bro
wn
or b
lack
spo
tsD
escr
ipti
on: S
pora
dica
lly o
ccur
ring
spe
cks,
eith
er s
pher
ical
with
irre
gula
r ou
tlin
es o
r lik
e pl
atel
ets
with
cle
arly
defi
ned
, str
aigh
t out
lines
Caus
es:
Rem
edia
l act
ions
:
Tear
ing
or p
eelin
g of
f of t
hin
laye
rs o
f mel
t whi
ch fo
rm o
n th
e su
rfac
e of
the
cylin
der a
nd th
e sc
rew
Clea
n th
e pl
astic
izin
g un
it m
echa
nica
lly. S
ee re
com
men
ded
proc
edur
e fo
r pro
duct
ion
stop
page
s. C
heck
pla
stic
izin
g un
it fo
r wea
r
Cont
amin
atio
n of
the
gran
ules
/reg
rind
Chec
k gr
anul
es fo
r pos
sibl
e co
ntam
inat
ion.
Sto
re g
ranu
les
in a
dus
t-fr
ee p
lace
. Cle
an c
onta
min
ated
pos
t-co
nsum
er
artic
les
befo
re re
grin
ding
. Do
not r
egrin
d da
mp
or th
erm
ally
da
mag
ed a
rtic
les.
Che
ck th
e dr
ying
and
feed
sys
tem
s fo
r co
ntam
inat
ion
4 F
ault
cat
egor
y: S
peck
s
26
Bli
ster
sD
escr
ipti
on: S
olid
, rou
nd o
r elo
ngat
ed b
umps
or l
umps
on
the
surfa
ce w
hich
are
re-
stric
ted
to v
ery
smal
l are
as a
nd a
re n
ot n
eces
saril
y vi
sibl
e on
bot
h si
des
of th
e m
olde
d pa
rt
Caus
es:
Rem
edia
l act
ions
:
Unm
elte
d m
ater
ial,
or a
ir dr
awn
in d
urin
g m
eter
ing:
+ sc
rew
cut
too
deep
Use
a s
uita
ble
scre
w
Unm
elte
d m
ater
ial,
or a
ir dr
awn
in d
urin
g m
eter
ing:
+ m
eter
ing
stro
ke e
xcee
ds 3
DKe
ep m
eter
ing
stro
ke to
bet
wee
n 1
and
3D
Unm
elte
d m
ater
ial,
or a
ir dr
awn
in d
urin
g m
eter
ing:
+ ba
ck p
ress
ure
too
low
Incr
ease
bac
k pr
essu
re
Unm
elte
d m
ater
ial,
or a
ir dr
awn
in d
urin
g m
eter
ing:
+ m
elt t
empe
ratu
re to
o lo
wRa
ise
mel
t tem
pera
ture
Unm
elte
d m
ater
ial,
or a
ir dr
awn
in d
urin
g m
eter
ing:
+ sc
rew
spe
ed to
o hi
ghRe
duce
scr
ew s
peed
5 F
ault
cat
egor
y: S
urfa
ce ir
regu
lari
ties
27
Del
amin
atio
nD
escr
ipti
on: S
epar
atio
n or
fl ak
ing
off o
f sur
face
mat
eria
l, ei
ther
ove
r the
ent
ire
mol
ding
or l
ocal
ly n
ear t
he s
prue
Caus
es:
Rem
edia
l act
ions
:
Exce
ssiv
e sh
ear s
tres
s. G
ate
too
thin
. In
ject
ion
spee
d to
o hi
ghRe
duce
she
ar s
tres
s. W
iden
gat
e. R
educ
e in
ject
ion
spee
d
Cont
amin
atio
n ca
used
by
inco
mpa
tible
resi
nsCl
ean
plas
ticiz
ing
unit.
Che
ck m
ater
ial i
n ho
pper
and
feed
lin
es fo
r con
tam
inat
ion
by o
ther
mat
eria
ls
Uns
uita
ble
pigm
ent m
aste
rbat
chU
se a
sui
tabl
e pi
gmen
t mas
terb
atch
28
Loca
lize
d si
nk m
arks
Des
crip
tion
: Dis
tinc
t, lo
caliz
ed h
ollo
ws
in th
e su
rfac
e, g
ener
ally
foun
d op
posi
te
ribs
, at t
hick
er s
ecti
ons,
cor
es, w
eld
lines
, con
stri
ctio
ns, h
ot ru
nner
noz
zles
and
th
e en
d of
fl ow
pat
hs
Caus
es:
Rem
edia
l act
ions
:
No
com
pens
atio
n fo
r vol
ume
cont
ract
ion
durin
g th
e co
olin
g ph
ase
Com
pens
ate
for v
olum
e co
ntra
ctio
n: A
djus
t wal
l thi
ckne
ss/
rib th
ickn
ess
ratio
to s
uit m
ater
ial,
incr
ease
hol
ding
pre
s-su
re a
nd h
oldi
ng p
ress
ure
time,
incr
ease
noz
zle
aper
ture
an
d ga
te c
ross
sec
tion.
Red
uce
tem
pera
ture
of m
elt a
nd to
ol
(may
lead
to v
oids
). Ch
eck
mel
t cus
hion
. Con
ceal
sin
k m
arks
if
nece
ssar
y
29
Not
ches
alo
ng w
eld
line
, pro
noun
ced
wel
d li
neD
escr
ipti
on: T
angi
ble
or v
isib
le n
otch
alo
ng th
e w
eld
line
Caus
es:
Rem
edia
l act
ions
:
Insu
ffi ci
ent m
old
vent
ing
Impr
ove
mol
d ve
ntin
g, e
spec
ially
at e
nd o
f fl o
w p
ath
Inad
equa
te fl
ow p
rope
rtie
s of
the
resi
n. In
ject
ion
spee
d to
o lo
w. W
alls
too
thin
or fl
ow
pat
hs to
o lo
ng
Impr
ove
fl ow
pro
pert
ies
by in
crea
sing
tem
pera
ture
of m
elt
and
mol
d. R
aise
inje
ctio
n sp
eed.
Incr
ease
sec
tion
thic
knes
s or
, if n
eces
sary
, rel
ocat
e ga
te s
o as
to s
hort
en fl
ow p
aths
Not
e: M
ostly
with
hig
h-vi
scos
ity o
r qui
ck-s
ettin
g th
erm
o-pl
astic
s. In
man
y ca
ses,
var
ioth
erm
met
hods
can
be
used
to
conc
eal t
he w
eld
line
30
Gro
oves
, rec
ord
groo
ves,
sti
ck-s
lip
effe
ctD
escr
ipti
on: F
ine,
con
cent
ric
groo
ves
arou
nd th
e sp
rue;
gro
oves
par
alle
l to
the
fl ow
fron
t in
thin
-wal
led
area
s
Caus
es:
Rem
edia
l act
ions
:
Puls
atin
g m
elt fl
ow
in th
e m
old,
cau
sed
by e
xces
sive
coo
ling
of th
e fl o
w fr
ont,
caus
e:Tr
y to
mai
ntai
n an
eve
n, ra
pid
mel
t fl o
w
inje
ctio
n sp
eed
too
low
Incr
ease
inje
ctio
n sp
eed
mel
t tem
pera
ture
too
low
Rais
e m
elt t
empe
ratu
re
mol
d te
mpe
ratu
re to
o lo
w o
r Ra
ise
mol
d te
mpe
ratu
re
wal
ls to
o th
inIn
crea
se w
all t
hick
ness
31
Mel
t cus
hion
var
ies
in s
ize
Des
crip
tion
: Siz
e of
mel
t cus
hion
fl uc
tuat
es w
idel
y, b
ecom
ing
alm
ost n
on-e
xist
ent
at ti
mes
6 F
ault
cat
egor
y: P
roce
ssin
g
Caus
es:
Rem
edia
l act
ions
:
Non
-ret
urn
valv
e de
fect
ive
or w
orn
Chec
k no
n-re
turn
val
ve a
nd re
plac
e if
nece
ssar
y
Irre
gula
r met
erin
gCh
eck
cylin
der b
ore
for w
ear a
nd in
sert
a s
leev
e if
nece
ssar
y,
or u
se a
new
pla
stic
izin
g un
it
32
Gen
eral
war
ping
Des
crip
tion
: Mol
ded
part
s do
not
mat
ch s
peci
fi cat
ion
draw
ing,
suf
fer w
arpa
ge
at c
orne
rs o
r do
not fi
t a
ccur
atel
y
Caus
es:
Rem
edia
l act
ions
:
Part
poo
rly
desi
gned
. Uns
uita
ble
orie
ntat
ion
of g
lass
fi be
rs.
Uns
uita
ble
dist
ribut
ion
of w
all t
hick
ness
Opt
imiz
e pa
rt d
esig
n. Im
prov
e or
ient
atio
n of
gla
ss fi
bers
by
optim
izin
g ga
te. O
ptim
ize
dist
ribut
ion
of w
all t
hick
ness
Hol
ding
pre
ssur
e in
effe
ctiv
e. N
on-r
etur
n va
lve
wor
nSw
itch
from
inje
ctio
n to
hol
ding
pre
ssur
e at
a la
ter s
tage
. In
spec
t non
-ret
urn
valv
e an
d re
plac
e if
nece
ssar
y
Not
e: A
ll po
ssib
le c
ause
s of
def
ect,
asso
ciat
ed re
med
ies
and
thei
r int
erde
pend
enci
es a
re to
o co
mpl
ex to
go
into
her
e
7 F
ault
cat
egor
y: W
arpi
ng
33
8 F
ault
cat
egor
y: G
loss
Fros
ting
Des
crip
tion
: Rou
gh, m
att p
art s
urfa
ces
of th
e ed
ges
Caus
es:
Rem
edia
l act
ions
:
Inje
ctio
n sp
eed
too
low
Rais
e in
ject
ion
spee
d
Mol
d te
mpe
ratu
re to
o lo
wRa
ise
the
tem
pera
ture
of t
he m
old.
Fit
ther
mal
insu
latio
n ro
und
mol
d. U
se a
mor
e ef
fi cie
nt te
mpe
ratu
re c
ontr
ol u
nit
Not
e: O
nly
affe
cts
glas
s-fi b
er-r
einf
orce
d th
erm
opla
stic
s.
Very
evi
dent
on
amor
phou
s th
erm
opla
stic
s, le
ss s
o on
sem
i-cr
ysta
lline
ther
mop
last
ics
34
Poor
glo
ss w
ith
poli
shed
sur
face
sD
escr
ipti
on: P
art d
oes
not m
eet g
loss
requ
irem
ents
(eit
her o
ver t
he w
hole
su
rfac
e or
in a
cer
tain
are
a)
Caus
es:
Rem
edia
l act
ions
:
Mol
d w
orn
or n
ot p
rope
rly
polis
hed
Polis
h m
old
thor
ough
ly
Inje
ctio
n sp
eed
too
low
, pos
sibl
y du
e to
poo
r ven
ting
Incr
ease
inje
ctio
n sp
eed,
if n
eces
sary
by
impr
oved
ven
ting
Fluc
tuat
ions
in m
old
tem
pera
ture
cau
sed
by in
adeq
uate
co
olin
gCh
eck
cons
iste
ncy
of m
old
tem
pera
ture
Mat
eria
l not
pro
perl
y dr
ied
Chec
k dr
ying
pro
cess
Hol
ding
pre
ssur
e in
effe
ctiv
eIm
prov
e ef
fect
iven
ess
of h
oldi
ng p
ress
ure
by in
crea
sing
ho
ldin
g pr
essu
re, e
xten
ding
hol
ding
pre
ssur
e tim
e an
d if
nece
ssar
y in
crea
sing
gat
e si
ze
35
Caus
es:
Rem
edia
l act
ions
:
Mol
d w
orn
or n
ot p
rope
rly
polis
hed
Polis
h m
old
thor
ough
ly
Inje
ctio
n sp
eed
too
low
, pos
sibl
y du
e to
poo
r ven
ting
Incr
ease
inje
ctio
n sp
eed,
if n
eces
sary
by
impr
oved
ven
ting
Fluc
tuat
ions
in m
old
tem
pera
ture
cau
sed
by in
adeq
uate
co
olin
gCh
eck
cons
iste
ncy
of m
old
tem
pera
ture
Mat
eria
l not
pro
perl
y dr
ied
Chec
k dr
ying
pro
cess
Hol
ding
pre
ssur
e in
effe
ctiv
eIm
prov
e ef
fect
iven
ess
of h
oldi
ng p
ress
ure
by in
crea
sing
ho
ldin
g pr
essu
re, e
xten
ding
hol
ding
pre
ssur
e tim
e an
d if
nece
ssar
y in
crea
sing
gat
e si
ze
Vari
atio
ns in
glo
ss o
n th
e su
rfac
e of
the
mol
ded
arti
cle
Des
crip
tion
: Var
iati
ons
in g
loss
ove
r all
or p
art o
f the
sur
face
of t
he a
rtic
le
Caus
es:
Rem
edia
l act
ions
:
Inje
ctio
n sp
eed
too
low
Rais
e in
ject
ion
spee
d
Cavi
ty s
urfa
ce w
orn
or c
orro
ded
Re-m
achi
ne m
old
surf
ace
Fluc
tuat
ions
in m
old
tem
pera
ture
. Pro
blem
s in
the
tem
pera
-tu
re c
ontr
ol c
ircui
t, e.
g. le
akag
e, b
lock
ed c
oolin
g ch
anne
l, te
mpe
ratu
re c
ontr
ol u
nit d
efec
tive
Serv
ice
the
tem
pera
ture
con
trol
sys
tem
and
elim
inat
e an
y le
aks.
Impr
ove
tem
pera
ture
con
trol
by
addi
ng m
ore
heat
ing-
cool
ing
chan
nels
, inc
reas
ing
the
thro
ughp
ut o
f the
tem
pera
-tu
re c
ontr
ol m
ediu
m o
r cha
ngin
g th
e m
ediu
m (e
.g. u
se w
ater
in
stea
d of
oil)
Sprin
gy m
old
elem
ents
, suc
h as
cor
es o
r eje
ctor
sIn
crea
se m
old
rigid
ity
36
Loca
lize
d, g
loss
y, fi
nger
-sha
ped
depr
essi
ons
Des
crip
tion
: Glo
ssy
depr
essi
ons,
oft
en n
ear t
he s
prue
, at c
ores
or i
n th
e vi
cini
ty o
f hot
runn
er u
nits
Caus
es:
Rem
edia
l act
ions
:
Prem
atur
e de
mol
dEx
tend
cyc
le ti
me
Hol
ding
pre
ssur
e to
o lo
w a
nd h
oldi
ng p
ress
ure
time
too
shor
t
Incr
ease
hol
ding
pre
ssur
e, in
crea
se h
oldi
ng p
ress
ure
time,
ch
eck
mel
t cus
hion
, che
ck, a
nd if
nec
essa
ry in
crea
se n
ozzl
e ap
ertu
re a
nd g
ate
cros
s se
ctio
n
Switc
h fr
om in
ject
ion
to h
oldi
ng p
ress
ure
mad
e to
o so
onSw
itch
to h
oldi
ng p
ress
ure
at a
late
r sta
ge
Mol
d te
mpe
ratu
re to
o hi
gh in
pla
ces
Redu
ce m
old
tem
pera
ture
loca
lly b
y m
eans
of a
dditi
onal
co
olin
g ch
anne
ls o
r sep
arat
e te
mpe
ratu
re c
ontr
ol
Not
e: S
ee a
lso:
Mat
t sur
face
def
ects
37
Dul
l spo
ts, m
att p
atch
esD
escr
ipti
on: U
nifo
rm, c
lear
ly d
efi n
ed v
elve
ty a
reas
on
surf
ace
Caus
es:
Rem
edia
l act
ions
:
Flow
fron
ts w
ith d
iffer
ent v
eloc
ities
(with
sev
eral
gat
ing
poin
ts)
Even
out
diff
eren
ces
in fl
ow fr
ont v
eloc
ities
by
impr
ov-
ing
the
bala
nce
of th
e ga
ting
syst
em (w
here
sev
eral
feed
po
ints
are
invo
lved
)
Tear
ing
of a
lread
y so
lidifi
ed o
uter
ski
n at
sha
rp b
ends
and
ab
rupt
cha
nges
in w
all t
hick
ness
Roun
d of
f or p
olis
h tr
ansi
tion
zone
s an
d ab
rupt
cha
nges
in
wal
l thi
ckne
ss in
the
runn
er a
nd m
old;
bal
ance
fl ow
fron
t ve
loci
ties
Not
e: S
ee a
lso:
Fla
king
38
Mat
t sur
face
def
ects
nea
r ho
t run
ner
unit
sD
escr
ipti
on: M
att s
urfa
ce d
efec
ts n
ear h
ot ru
nner
uni
ts
Caus
es:
Rem
edia
l act
ions
:
Prem
atur
e de
mol
dIn
crea
se c
oolin
g tim
e
Mol
d te
mpe
ratu
re a
t hot
runn
er to
o hi
ghIm
prov
e th
erm
al is
olat
ion
of h
ot ru
nner
s, re
duce
mol
d te
m-
pera
ture
Core
tem
pera
ture
too
high
Mak
e su
re c
ore
is a
dequ
atel
y co
oled
39
Poor
mat
t eff
ect o
n te
xtur
ed s
urfa
ces
Des
crip
tion
: Par
t sur
face
doe
s no
t mee
t mat
tnes
s re
quir
emen
ts
Caus
es:
Rem
edia
l act
ions
:
Inje
ctio
n sp
eed
and
mol
d te
mpe
ratu
re to
o lo
wIn
crea
se in
ject
ion
spee
d an
d m
old
tem
pera
ture
Hol
ding
pre
ssur
e in
effe
ctiv
eSw
itch
to h
oldi
ng p
ress
ure
at a
late
r sta
ge a
nd in
crea
se it
s le
vel
Surf
ace
text
ure
of m
old
cavi
ty p
oor o
r wor
nRe
-mac
hine
mol
d su
rfac
e
40
Dam
aged
gra
in o
n th
e m
olde
d ar
ticl
eD
escr
ipti
on: R
ough
, tor
n su
rfac
e w
ith
groo
ves
in th
e di
rect
ion
of d
emol
ding
, m
ostl
y at
the
sam
e pl
ace
Caus
es:
Rem
edia
l act
ions
:
Dra
ft a
ngle
s to
o sm
all
Incr
ease
dra
ft a
ngle
s
Mol
d su
rfac
e da
mag
edRe
-mac
hine
mol
d su
rfac
e
Cavi
ty p
ress
ure
too
high
Redu
ce c
avity
pre
ssur
e. S
witc
h fr
om in
ject
ion
to h
oldi
ng
pres
sure
ear
lier.
Redu
ce h
oldi
ng p
ress
ure.
Opt
imiz
e in
ject
ion
rate
. Inc
reas
e m
elt t
empe
ratu
re w
ithin
acc
epta
ble
limits
Inad
equa
te m
old
rigid
itySt
reng
then
mol
d
Not
e: S
corin
g ca
n of
ten
only
be
iden
tifi e
d us
ing
optic
al a
ids
41
Caus
es:
Rem
edia
l act
ions
:
Dra
ft a
ngle
s to
o sm
all
Incr
ease
dra
ft a
ngle
s
Mol
d su
rfac
e da
mag
edRe
-mac
hine
mol
d su
rfac
e
Cavi
ty p
ress
ure
too
high
Redu
ce c
avity
pre
ssur
e. S
witc
h fr
om in
ject
ion
to h
oldi
ng
pres
sure
ear
lier.
Redu
ce h
oldi
ng p
ress
ure.
Opt
imiz
e in
ject
ion
rate
. Inc
reas
e m
elt t
empe
ratu
re w
ithin
acc
epta
ble
limits
Inad
equa
te m
old
rigid
itySt
reng
then
mol
d
Not
e: S
corin
g ca
n of
ten
only
be
iden
tifi e
d us
ing
optic
al a
ids
9 F
ault
cat
egor
y: M
echa
nica
l pro
pert
ies
Inad
equa
te w
eld
line
str
engt
hD
escr
ipti
on: F
ailu
re o
f par
t nea
r wel
d lin
e
Caus
es:
Rem
edia
l act
ions
:
Insu
ffi ci
ent m
old
vent
ing
Impr
ove
mol
d ve
ntin
g
Inad
equa
te fl
ow p
rope
rtie
s of
the
resi
n. In
ject
ion
spee
d to
o lo
w. W
alls
too
thin
or fl
ow
pat
hs to
o lo
ng
Impr
ove
fl ow
pro
pert
ies.
Incr
ease
inje
ctio
n sp
eed.
Rai
se
mel
t and
mol
d te
mpe
ratu
re. I
ncre
ase
wal
l thi
ckne
ss o
r re
loca
te g
ates
so
as to
sho
rten
fl ow
pat
hs
42
Mec
hani
call
y de
fect
ive
part
Des
crip
tion
: Par
t una
ble
to w
iths
tand
mec
hani
cal s
tres
s
Caus
es:
Rem
edia
l act
ions
:
Mec
hani
cal s
tres
s to
o hi
ghCh
eck
desi
gn a
gain
st m
echa
nica
l req
uire
men
ts.
(inte
rnal
str
ess,
resi
stan
ce o
f the
resi
n to
var
ious
med
ia)
Deg
rada
tion
of th
e m
ater
ial c
ause
d by
faul
ty d
ryin
g or
th
erm
al o
verl
oadi
ngM
onito
r mel
t tem
pera
ture
, res
iden
ce ti
me
and
dryi
ng
proc
ess
Uns
uita
ble
posi
tion
of w
eld
line
Loca
te w
eld
lines
aw
ay fr
om m
ain
area
s of
str
ess
Poor
eje
ctio
n ch
arac
teris
tics
at s
crew
bos
ses
etc.
Prev
ent p
art f
rom
bei
ng d
amag
ed d
urin
g de
mol
d, im
prov
e ej
ectio
n ch
arac
teris
tics
43
10 F
ault
cat
egor
y: S
trea
king
Cold
fl ow
mar
ks, fl
aki
ngD
escr
ipti
on: S
urfa
ce a
ppea
rs fl
aky
wit
h al
tern
atin
g gl
ossy
and
mat
t are
as,
mos
tly
near
the
spru
e
Caus
es:
Rem
edia
l act
ions
:
Dis
plac
emen
t of m
ater
ial w
hich
has
alre
ady
cool
edIn
ject
mat
eria
l in
stag
es, s
tart
ing
slow
ly a
nd g
radu
ally
in
crea
sing
spe
ed. R
educ
e m
old
tem
pera
ture
. Des
ign
gate
s w
ith ra
dii a
nd p
olis
h th
em
44
Jett
ing
Des
crip
tion
: Gen
eral
ly s
erpe
ntin
e st
rand
of t
he m
elt fi
rst
inje
cted
into
the
mol
d,
foun
d ne
ar th
e sp
rue
or a
t con
stri
cted
sec
tions
, and
vis
ible
on
the
part
sur
face
Caus
es:
Rem
edia
l act
ions
:
Uns
uita
ble
desi
gn o
f gat
e or
nar
row
sec
tions
pre
vent
ing
lam
inar
fl ow
. Gat
e po
sitio
n w
ith n
o op
posi
ng w
all.
Gat
e cr
oss
sect
ion
or n
arro
w s
ectio
n to
o sm
all
Rede
sign
gat
e. P
ositi
on g
ate
oppo
site
a w
all.
Enla
rge
gate
cr
oss
sect
ion.
Red
esig
n ch
ange
s in
cro
ss s
ectio
n
Inje
ctio
n sp
eed
too
high
Inje
ct m
ater
ial s
low
ly a
t fi r
st, t
hen
switc
h to
a fa
ster
spe
ed
45
Larg
e-ar
ea s
ilve
r st
reak
sD
escr
ipti
on: B
rush
-sha
ped,
elo
ngat
ed s
trea
ks s
prea
d ov
er a
larg
e ar
ea
Caus
es:
Rem
edia
l act
ions
:
Met
erin
g st
roke
of t
he p
last
iciz
ing
unit
too
long
Use
a la
rger
pla
stic
izin
g un
it to
redu
ce th
e le
ngth
of t
he
met
erin
g st
roke
(<3D
). If
plas
ticiz
ing
unit
cann
ot b
e ch
ange
d: In
crea
se te
mpe
ratu
re o
f fee
d se
ctio
n, re
duce
sc
rew
spe
ed, i
ncre
ase
cycl
e tim
e an
d, a
s an
add
ition
al, o
p-tio
nal m
easu
re, i
ncre
ase
the
mel
t cus
hion
by
1–2
D if
po
ssib
le
Air e
ntra
inm
ent d
urin
g m
eter
ing
Opt
imiz
e pl
astic
izin
g co
nditi
ons.
Incr
ease
bac
k pr
essu
re
(with
in a
ccep
tabl
e lim
its).
Redu
ce s
crew
retr
actio
n. P
ositi
on
inje
ctio
n no
zzle
tigh
t up
agai
nst h
ot ru
nner
mol
d
Not
e: S
omet
imes
occ
urs
in a
ssoc
iatio
n w
ith b
liste
ring
46
Knu
ckle
line
Des
crip
tion
: Whe
n lig
ht fa
lls o
n th
e pa
rt fr
om a
cer
tain
ang
le, a
line
or s
him
-m
er c
an c
lear
ly b
e se
en o
n it
s su
rfac
e, fr
eque
ntly
at w
eld
lines
, rib
s, a
brup
t ch
ange
s in
sec
tion
thic
knes
s or
spl
its
Caus
es:
Rem
edia
l act
ions
:
Elas
tic d
efor
mat
ion
of s
lidin
g co
res
Impr
ove
slid
e su
ppor
ts o
r inc
reas
e m
old
rigid
ity
Gla
ss fi
bers
per
pend
icul
ar to
fl ow
dire
ctio
n at
wel
d lin
esAl
ter p
ositi
on o
f wel
d lin
es, i
f nec
essa
ry b
y ch
angi
ng
loca
tion
or n
umbe
r of g
ates
Abru
pt c
hang
es in
stif
fnes
s at
ribs
or w
here
sec
tion
thic
knes
s ch
ange
sAv
oid
abru
pt c
hang
es in
wal
l thi
ckne
ss in
favo
r of g
radu
al
tran
sitio
ns
47
Sur
face
mar
red
by li
near
gro
oves
, scr
atch
esD
escr
ipti
on: G
roov
es a
nd s
crat
ches
runn
ing
in th
e de
mol
ding
dir
ecti
on, a
lso
visi
ble
as m
att s
trea
ks o
n hi
gh-g
loss
sur
face
s
Caus
es:
Rem
edia
l act
ions
:
Cavi
ty s
urfa
ce d
amag
edCh
eck
cavi
ty s
urfa
ce a
nd re
-mac
hine
if n
eces
sary
, pol
ish
in
dem
oldi
ng d
irect
ion
Elas
tic d
efor
mat
ion
of s
lidin
g co
res
Opt
imiz
e sl
idin
g co
res
Cavi
ty p
ress
ure
too
high
Redu
ce c
avity
pre
ssur
e. S
witc
h fro
m in
ject
ion
to h
oldi
ng p
ress
ure
earli
er. R
educ
e ho
ldin
g pr
essu
re. O
ptim
ize
inje
ctio
n ra
te. I
ncre
ase
mel
t tem
pera
ture
with
in a
ccep
tabl
e lim
its
Inad
equa
te m
old
rigid
itySt
reng
then
mol
d
Not
e: S
ee a
lso:
Mol
d op
enin
g no
ise
48
U-s
hape
d st
reak
s, m
oist
ure
stre
aks
Des
crip
tion
: Elo
ngat
ed, p
enci
l-lik
e st
reak
s, o
pen
tow
ards
the
fl ow
dir
ecti
on:
in m
ild c
ases
may
be
sing
le s
trea
ks
Caus
es:
Rem
edia
l act
ions
:
Resi
dual
moi
stur
e co
nten
t of p
elle
ts to
o hi
ghCh
eck
dryi
ng p
roce
ss (t
empe
ratu
re, t
ime
and
hour
ly
thro
ughp
ut).
Exam
ine
drye
r fi lt
er fo
r con
tam
inat
ion.
Che
ck
dire
ctio
n of
rota
tion
of d
rive
mot
or
49
Ove
rhea
ting
str
eaks
, sil
ver
stre
aks
Des
crip
tion
: Elo
ngat
ed s
ilver
str
eaks
Caus
es:
Rem
edia
l act
ions
:Ex
cess
ive
ther
mal
load
on
the
mel
t:m
elt t
empe
ratu
re to
o hi
ghRe
duce
the
ther
mal
load
on
the
mel
t, Re
duce
mel
t tem
pera
ture
Exce
ssiv
e th
erm
al lo
ad o
n th
e m
elt:
mel
t res
iden
ce ti
me
too
long
Redu
ce th
e th
erm
al lo
ad o
n th
e m
elt,
use
a sm
alle
r scr
ew d
iam
eter
Exce
ssiv
e th
erm
al lo
ad o
n th
e m
elt:
sc
rew
spe
ed to
o hi
ghRe
duce
the
ther
mal
load
on
the
mel
t, re
duce
scr
ew s
peed
Exce
ssiv
e th
erm
al lo
ad o
n th
e m
elt:
no
zzle
and
fl ow
cha
nnel
cro
ss s
ectio
ns to
o sm
all
Redu
ce th
e th
erm
al lo
ad o
n th
e m
elt,
wid
en n
ozzl
e an
d ru
nner
dia
met
er
Exce
ssiv
e th
erm
al lo
ad o
n th
e m
elt:
failu
re to
redu
ce te
mpe
ratu
re d
urin
g a
brea
k in
pro
duct
ion
Redu
ce th
e th
erm
al lo
ad o
n th
e m
elt,
se
e no
tes
on p
rodu
ctio
n st
oppa
ges
Not
e: O
ften
app
ears
sim
ilar t
o m
oist
ure
stre
aks
50
Larg
e bu
bble
sD
escr
ipti
on: A
ir-fi l
led
bubb
les
in th
e w
alls
Caus
es:
Rem
edia
l act
ions
:
Air e
ntra
inm
ent d
urin
g m
eter
ing
Chec
k gr
anul
e fe
ed fo
r air
entr
ainm
ent.
Incr
ease
hol
ding
pr
essu
re (w
ithin
acc
epta
ble
limits
). Re
duce
scr
ew re
trac
tion
(suc
k ba
ck)
Capa
city
of p
last
iciz
ing
unit
exce
eded
Use
a p
last
iciz
ing
unit
one
size
larg
er if
the
scre
w s
trok
e is
gr
eate
r tha
n 3D
51
Cold
slu
g, c
old
fl ow
mar
king
, irr
egul
ar m
att a
rea
Des
crip
tion
: Col
d m
ater
ial t
rapp
ed a
t the
mol
ded-
part
sur
face
Caus
es:
Rem
edia
l act
ions
:
Cold
slu
g w
ell i
n co
ld ru
nner
abs
ent o
r too
sm
all
Inco
rpor
ate
or im
prov
e co
ld s
lug
wel
l
Esca
pe o
f mat
eria
l fro
m in
ject
ion
nozz
le o
r hot
runn
erSp
eed
up s
crew
retr
actio
n, im
prov
e th
erm
al is
olat
ion
in h
ot
runn
er
Noz
zle
aper
ture
too
smal
l, no
zzle
tem
pera
ture
too
low
Incr
ease
siz
e of
noz
zle
aper
ture
, ins
tall
a m
ore
pow
erfu
l he
ater
ban
d, c
heck
ther
moc
oupl
e an
d re
gula
tor
52
Sm
all b
ubbl
esD
escr
ipti
on: E
ntra
pped
air
sim
ilar t
o vo
ids,
but
ver
y m
uch
smal
ler d
iam
eter
an
d m
ore
num
erou
s
Caus
es:
Rem
edia
l act
ions
:
Exce
ssiv
e m
oist
ure
in m
ater
ial
Chec
k dr
ying
pro
cess
Uns
uita
ble
vent
ing
unit
Sele
ct a
sui
tabl
e ve
nted
scr
ew o
r sub
stitu
te a
con
vent
iona
l sc
rew
for t
he v
ente
d sc
rew
and
pre
-dry
the
mat
eria
l
Not
e:O
ften
occ
urs
in c
onju
nctio
n w
ith e
xten
sive
silv
er s
trea
ks
53
Tear
dro
psD
escr
ipti
on: T
ear d
rop-
shap
ed ir
regu
lari
ties
cau
sed
by e
ntra
pped
air
Caus
es:
Rem
edia
l act
ions
:
Air t
rapp
ed in
the
mol
d, e
.g. i
n en
grav
ed a
reas
, gro
oves
or
depr
essi
ons
Redu
ce in
ject
ion
spee
d in
the
criti
cal a
rea.
Impr
ove
mol
d ve
ntin
g at
wel
d lin
es a
nd d
epre
ssio
ns, r
ibs
and
engr
aved
ar
eas.
App
ly a
vac
uum
to th
e m
old
Caus
es:
Rem
edia
l act
ions
:
Exce
ssiv
e m
oist
ure
in m
ater
ial
Chec
k dr
ying
pro
cess
Uns
uita
ble
vent
ing
unit
Sele
ct a
sui
tabl
e ve
nted
scr
ew o
r sub
stitu
te a
con
vent
iona
l sc
rew
for t
he v
ente
d sc
rew
and
pre
-dry
the
mat
eria
l
Not
e:O
ften
occ
urs
in c
onju
nctio
n w
ith e
xten
sive
silv
er s
trea
ks
54
Crat
ers,
pin
hole
s, d
impl
esD
escr
ipti
on: D
epre
ssio
ns a
s sm
all a
s a
pinh
ead
Caus
es:
Rem
edia
l act
ions
:
Mat
eria
l deg
rada
tion
Redu
ce m
elt t
empe
ratu
re a
nd re
side
nce
time
Faul
ty p
igm
enta
tion
(usi
ng in
com
patib
le p
igm
ents
in in
-pla
nt
colo
ring,
e.g
. the
wro
ng ty
pe o
f car
bon
blac
k)U
se c
ompa
tible
pig
men
ts o
r a d
iffer
ent t
ype
of c
arbo
n bl
ack
Too
muc
h ca
rbon
bla
ckRe
duce
car
bon
blac
k co
nten
t
Mol
d te
mpe
ratu
re to
o lo
w
Rais
e m
old
tem
pera
ture
sig
nifi c
antly
55
Gre
y sp
ecks
, met
alli
c sp
ecks
Des
crip
tion
: Gre
y fo
reig
n pa
rtic
les
whi
ch a
ppea
r shi
ny w
hen
lit fr
om c
erta
in
angl
e.
Caus
es:
Rem
edia
l act
ions
:
Plas
ticiz
ing
unit
wor
nCh
eck
for w
ear o
n sc
rew
, cyl
inde
r and
non
-ret
urn
valv
e
Fore
ign
part
icle
s pr
oduc
ed b
y ab
rasi
on o
f fee
d pi
pes,
co
ntai
ners
and
hop
pers
Chec
k fe
ed p
ipes
, con
tain
ers
and
hopp
ers
for a
bras
ion.
Use
st
ainl
ess
stee
l for
feed
pip
es, c
onta
iner
s an
d ho
pper
s, a
lu-
min
um a
nd ti
npla
te a
re u
nsui
tabl
e. A
void
cor
ners
as
far a
s po
ssib
le. I
f not
, des
ign
them
with
larg
e ra
dii
Gra
nula
tor f
or re
grin
d w
orn
Carr
y ou
t reg
ular
mai
nten
ance
on
gran
ulat
ors
and
chec
k fo
r ab
rasi
on a
nd d
amag
e
56
Mic
rosc
opic
cra
cks,
mic
ro-c
rack
sD
escr
ipti
on: M
icro
scop
ic c
rack
s in
the
part
, oft
en o
ccur
ing
only
at t
he s
urfa
ce
whe
re o
uter
fi br
es a
re u
nder
tens
ile s
tres
s
Caus
es:
Rem
edia
l act
ions
:
Exce
ssiv
e st
ress
in th
e pa
rtO
ptim
ize
proc
essi
ng p
aram
eter
s w
ith a
vie
w to
redu
cing
st
ress
. Inc
reas
e te
mpe
ratu
re o
f mol
d an
d m
elt.
Re-d
esig
n pa
rt s
o as
to re
duce
long
-ter
m o
uter
fi be
r str
ain
Cont
act w
ith u
nsui
tabl
e m
edia
Chec
k co
mpa
tibili
ty w
ith v
ario
us m
edia
. Che
ck s
tres
s-cr
ack-
indu
cing
effe
ct o
f rel
ease
and
ant
i-cor
rosi
ve a
gent
s. T
est
part
for c
hem
ical
resi
stan
ce to
cle
anin
g fl u
ids
and
degr
eas-
ing
agen
ts. C
heck
par
t’s re
sist
ance
to m
edia
enc
ount
ered
in
prac
tical
use
and
redu
ce m
echa
nica
l loa
d if
nece
ssar
y
57
Void
s, b
ubbl
es, v
acuo
les
Des
crip
tion
: Rou
nd o
r elo
ngat
ed b
ubbl
es g
ener
ally
onl
y vi
sibl
e in
tran
spar
ent
and
tran
sluc
ent p
arts
Caus
es:
Rem
edia
l act
ions
:
No
com
pens
atio
n fo
r vol
ume
cont
ract
ion
durin
g th
e co
olin
g ph
ase.
Hol
ding
pre
ssur
e in
effe
ctiv
e
Incr
ease
hol
ding
pre
ssur
e, in
crea
se h
oldi
ng p
ress
ure
time,
ch
eck
mel
t cus
hion
, che
ck, a
nd if
nec
essa
ry in
crea
se n
ozzl
e ap
ertu
re a
nd g
ate
cros
s se
ctio
n
No
com
pens
atio
n fo
r vol
ume
cont
ract
ion
durin
g th
e co
olin
g ph
ase.
Inje
ctio
n po
int p
oorly
pos
ition
ed, o
r par
t bad
ly d
esig
ned
Loca
te g
ate
in a
thic
k w
all s
ectio
n. R
evis
e pa
rt d
esig
n so
as
to a
void
abr
upt c
hang
es in
wal
l thi
ckne
ss
Not
e: C
ompl
y w
ith d
esig
n gu
idel
ines
for i
njec
tion-
mol
ded
part
s
58
Str
ingi
ngD
escr
ipti
on: L
ong,
thin
thre
ads
emer
ge fr
om th
e m
achi
ne o
r hot
runn
er n
ozzl
e
Caus
es:
Rem
edia
l act
ions
:
Noz
zle
aper
ture
too
larg
eSe
lect
a s
mal
ler n
ozzl
e ap
ertu
re, b
ut re
mem
ber c
ritic
al s
hear
Poor
ther
mal
isol
atio
n at
the
nozz
le p
oint
. Tem
pera
ture
of
the
nozz
le p
oint
whe
re it
mee
ts th
e ho
t run
ner t
oo h
igh.
In
suffi
cien
t suc
k-ba
ck
Opt
imiz
e th
erm
al is
olat
ion
at th
e no
zzle
poi
nt. R
educ
e no
zzle
tem
pera
ture
. Act
ivat
e su
ck-b
ack
or in
crea
se re
trac
-tio
n di
stan
ce (a
fter
met
erin
g in
the
case
of m
achi
ne n
ozzl
es,
befo
re m
eter
ing
in th
e ca
se o
f hot
runn
er n
ozzl
es)
Noz
zle
tem
pera
ture
too
high
at b
reak
ing
poin
tRe
duce
noz
zle
tem
pera
ture
Insu
ffi ci
ent s
crew
retr
actio
nAc
tivat
e sc
rew
retr
actio
n or
incr
ease
retr
actio
n di
stan
ce
Caus
es:
Rem
edia
l act
ions
:
Noz
zle
aper
ture
too
larg
eSe
lect
a s
mal
ler n
ozzl
e ap
ertu
re, b
ut re
mem
ber c
ritic
al s
hear
Poor
ther
mal
isol
atio
n at
the
nozz
le p
oint
. Tem
pera
ture
of
the
nozz
le p
oint
whe
re it
mee
ts th
e ho
t run
ner t
oo h
igh.
In
suffi
cien
t suc
k-ba
ck
Opt
imiz
e th
erm
al is
olat
ion
at th
e no
zzle
poi
nt. R
educ
e no
zzle
tem
pera
ture
. Act
ivat
e su
ck-b
ack
or in
crea
se re
trac
-tio
n di
stan
ce (a
fter
met
erin
g in
the
case
of m
achi
ne n
ozzl
es,
befo
re m
eter
ing
in th
e ca
se o
f hot
runn
er n
ozzl
es)
Noz
zle
tem
pera
ture
too
high
at b
reak
ing
poin
tRe
duce
noz
zle
tem
pera
ture
Insu
ffici
ent s
crew
retr
actio
nAc
tivat
e sc
rew
retr
actio
n or
incr
ease
retr
actio
n di
stan
ce
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Edition: 2011-09Order-no.: MS00056040 Printed in Germany · E
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