!trusion 
"hose and tubing# belts# ro$e and cable covers# sheeting and %ilms&
  Foaming Techniques  
Foam molding o%%ers the $ossibility o% increasing the si'e o% a $art without increasing weight and reducing the weight o% a $art with controlled change o% $ro$erties( Chemical %oaming involves mi!ing a chemical blowing agent with $ellets $rior to the $ellets being %ed into the %eed throat o% the molding machine(
)n*ection Molding
 
reheated# recycled5 heat until so%t# sha$e# then
cool(
networ6 7chemical reaction8# degrades 7doesn9t
melt8 when heated(
e!am$les+ urethane# e$o!y
)m$rove mechanical $ro$erties# $rocessing# durability(
Fillers 3  Added to im$rove tensile strength 4 abrasion resistance# toughness 4 decrease cost( !am$les+ carbon blac6# silica gel# wood %lour# glass# limestone# talc(
Plastici'ers 3 Added to reduce the glass transition tem$erature Tg below room tem$erature( Presence o% $lastici'er trans%orms brittle $olymer to a ductile one( Commonly added to P:C(
0tabili'ers ; Antio!idants# /: $rotection
<ubricants 3 Added to allow easier $rocessing $olymer =slides> through dies easier 7sodium stearate8(
Colorants 3 Dyes and $igments
Flame ?etardants 3 0ubstances containing chlorine# %luorine and boron(
Polymer Additives
Antimicrobials: /sed to control the build u$ o% bacteria# %ungi and
algae on the sur%ace o% $lastic $roducts( A wide range o% chemical
and natural com$ounds are used as antimicrobials( An e!am$le
would be naturally occurring silver ions used in $roducts li6e cell
$hones or organic acids in %ood3related $roducts(
Antistatics: /sed to minimi'e static electricity( These ty$es o%
additives can be mi!ed with the resin or a$$lied to the sur%ace o% the
$roduct( Antistatic additives are common to a wide variety o%
$roducts ranging %rom cosmetics to industrial goods to sensitive
electronic $arts(
Fibers: /sed to increase strength and sti%%ness( The most common
ty$e o% %ibers added %or strength would be carbon and glass( Glass3
rein%orced $lastic is more commonly 6nown as %iberglass(
 
@@
Processing Plastics ; Com$ression Molding
 

Processing Plastics ; )n*ection Molding
Thermo$lastics and some thermosets when ram retracts# $lastic $ellets dro$ %rom ho$$er  into barrel ram %orces $lastic into the heating chamber  7around the
s$reader 8 where the $lastic melts as it moves %orward molten $lastic is %orced under $ressure 7in*ected8 into the mold
7die8 cavity where it assumes the sha$e o% the mold
Barrel
http://en.wikipedia.org/wiki/Injection_mold
Plastic Injection Molding
O$erate plastic injection molding machines %rom -- tons to 22 Tons and E
o'( shot ca$acity( Many machines are ca$able o% multi$le core $ulls %or com$le!
plastic injection molded $arts(
Plastic injection molding grou$ services mid3si'ed manu%acturing com$anies in
the energy# electronics# li%e science# aeros$ace# %ood and beverage# industrial and
construction mar6ets( As a custom plastic injection molder we see6 diversity in
many mar6ets and %ocus our s6ills on $art geometry %or molding# material and
$roduct a$$lication(
Our plastic injection molding grou$ $rocesses most commodity and engineering
injection molded resins including P0# P# PP# AB0# 0A# PC# P:C# PBT# PP0#
TPO# TP/# POM# ylon EE# ylon and many custom com$ounded engineering
resins(
Processing Plastics ; !trusion
Thermo$lastics $lastic $ellets dro$ %rom ho$$er onto the turning screw $lastic $ellets melt as the turning screw $ushes them
%orward by the heaters molten $olymer is %orced under $ressure through the
sha$ing die to %orm the %inal $roduct 7e!trudate8
 
)n the e!trusion o% $lastics# raw thermo$lastic material in the
%orm o% small beads 7resin8 is gravity %ed %rom a to$ mounted
ho$$er into the barrel o% the e!truder( Additives 7colorants and
/: inhibitors in either liquid or $ellet %orm8 are o%ten used and
can be mi!ed into the resin $rior to arriving at the ho$$er(
The material enters through the %eed throat 7an o$ening near the
rear o% the barrel8 and comes into contact with the screw( The
rotating screw 7normally turning at u$ to - r$m8 %orces the
$lastic beads %orward into the barrel which is heated to the
desired melt tem$erature o% the molten $lastic 7which can range
%rom -C,HF to -I2C,2F de$ending on the $olymer8(
)n most $rocesses# a heating $ro%ile is set %or the barrel where
three or more inde$endent P)D controlled heater 'ones
gradually increase the tem$erature o% the barrel %rom the rear
7where the $lastic enters8 to the %ront( This allows the $lastic
beads to melt gradually as they are $ushed through the barrel
and lowers the ris6 o% overheating which may cause degradation
in the $olymer (
HH
Processing Plastics ; Blown3Film !trusion The manu%acture o% $lastic %ilm %or $roducts li6e sho$$ing bags is
done using a blown %ilm line(
This $rocess is the same as a regular e!trusion $rocess u$ until
the die( The die is an u$right cylinder with a circular o$ening similar
to a $i$e die( The diameter can be a %ew cm to more than m 
across( The molten $lastic is $ulled u$ward %rom the die by a $air
o% rollers high above the die(
Changing the s$eed o% these rollers changes the gauge 7wall
thic6ness8 o% the %ilm( Around the die sits an air3ring( The air3ring
cools the %ilm as it travels u$ward( )n the center o% the die is an air
outlet where com$ressed air can be %orced into the center o% the
e!truded circular $ro%ile# creating a bubble(
 
Glass
 A glass is an inorganic non metallic material that does not have a crystalline structure( 0uch materials are said to be amor$hous and are virtually solid liquids cooled at such a rate that crystals have not been able to %orm(
Ty$ical glasses range %rom the soda3lime silicate glass  %or soda bottles to the e!tremely high $urity silica glass  %or o$tical %ibers(
Glass is widely used %or windows# bottles# glasses %or drin6ing# trans%er $i$ing and rece$tacles %or highly corrosive liquids# o$tical glasses# windows %or nuclear a$$lications(
Most $roducts have been blown glass( )n recent times# most %lat glass has been $roduced using the %loat $rocess(
 
Glass Pro$erties+ :iscosity
:iscosity# η ,describes a %luidJs internal resistance to %low and may
be thought o% as a measure o% %luid %riction(
  33 relates shear stress 7τ8 and velocity gradient (dv/dy):
η has units o% 7Pa3s8
dy dv ,
τ =η
velocity gradient
Glass or noncrystalline materials do not solidi%y in the
same sense as crystalline materials( /$on cooling# a
glass becomes more and more viscous with
decreasing tem$erature(
liquid(
easily de%ormed(
0o%tening Point+
tem$( glass can be handled
without altering dimensions(
0train Point+
be%ore the onset o% $lastic
de%ormation (
Glasses+ 33 do not crystalli'e
  33 change in slo$e in s$ec( vol( curve at
glass transition tem$erature# T g 
  33 trans$arent 3 no grain boundaries to
scatter light
  33 have abru$t change in s$eci%ic
  volume at T m
 
-

-
Lor6ing range+
•  %used silica+ N @@(2 wt 0iO-
•  soda3lime glass+ I 0iO- 
 :ycor+ @E 0iO-# H B-O
•  borosilicate 7Pyre!8+
B-O# (2 a-O# -(2 Al-O s    o    d     a    -  l    i    m   
e     
9     6     %    
a   
f    u    s    e    d      s    i    l    i    c   
a   
done by hand(
a $arison 7tem$orary
and %orced to con%orm to
the mold contours by the
$ressure created %rom a
long glass $arts 7sheets#
rods# tubing and %ibers8
section(
0heet Glass Forming
!heet forming " continuous casting sheets are formed by floating the molten glass on a pool of
molten tin
Tem$ering+   33 $uts sur%ace o% glass $art into com$ression
  33 su$$resses growth o% crac6s %rom sur%ace scratches(
  33 sequence+
 
Tem$ered Glass
Fully tem$ered glass is roughly H times stronger than annealed glass o% the same thic6ness and con%iguration5 residual sur%ace com$ression must be over # $si %or Emm thic6ness# according to A0TM C H(
Tem$ered glass is manu%actured through a $rocess o% e!treme heating and ra$id cooling# ma6ing it harder than normal glass(
The ty$ical $rocess to $roduce tem$ered glass involves heating the glass to over # F# then ra$idly cooling to loc6 the glass sur%aces in a state o% com$ression and the core in a state o% tension(
Lhen glass cools down to ambient tem$erature# the center $lane o% the glass contracts more than the sur%aces( The contraction o% the center $lane $ulls the sur%aces into com$ression and the glass becomes very strong(
 
the glass to a uni%orm tem$erature o%
roughly -F(
regulated to ensure tem$erature
distortions(
%urnace# it is ra$idly cooled by a
series or air no''les( This ra$id
cooling $uts roughly - o% the glass
sur%ace into a state o% com$ression#
with the center core in tension(
 
0hattered Tem$ered Glass
The brittle nature o% tem$ered glass causes it to shatter into small oval3 sha$ed $ebbles when bro6en( This eliminates the danger o% shar$ edges( Due to this $ro$erty# along with its strength# tem$ered glass is o%ten re%erred to as sa%ety glass(
Tem$ered glass brea6s in a unique way( )% any $art o% the glass %ails# the entire $anel shatters at once( This distinguishes it %rom normal glass# which might e!$erience a small crac6 or locali'ed brea6age %rom an isolated im$act(
Tem$ered glass might also %ail long a%ter the event that caused the %ailure(
 
been heated and cooled and is
generally twice as strong as
annealed glass o% the same
thic6ness and con%iguration(
%ragments are ty$ically larger
glass(
%ully tem$ered glass# and is
intended %or a$$lications that do
not s$eci%ically require a sa%ety
glass $roduct(
eat 0trengthened
sur%ace com$ression between
#2 and I#2 $si %or E mm
glass# according to A0TM C H( s glass cannot be cut or drilled 
a%ter heat3strengthening and any
alterations# such as edge3grinding#
cause $remature %ailure(
 Annealing %loat glass is the $rocess o% controlled cooling
to $revent residual stress in the glass( )t is $art o% the %loat
glass manu%acturing $rocess(
$olished(
To anneal glass# the glass is heated and 6e$t %or a de%ined
$eriod o% time to relieve internal stresses(
Care%ully cooled under controlled conditions to ensure that
no stresses are reintroduced by chilling,cooling(
Float glass 7also called
been heat3strengthened or
B - Blown Ware
Q-2# reusable# lightweight#
into the arth9s atmos$here(
that has been sha$ed into a
s$eci%ic %orm but has not yet
been sintered(
7-28 -( Filler ; e(g( quart' 7%inely ground8
7-28 ( Flu!ing agent 7Felds$ar 8   33 aluminosilicates $lus 1R# aR# CaR
  33 u$on %iring 3 %orms low3melting3tem$( glass
 
C?C Technology
 An o$tical D image is acquired with a small camera# directly in your mouth(
The com$uter and C?CS D so%tware converts the digital $icture to a three dimensional virtual model o% your $re$$ed tooth( our dentist then designs your restoration right on screen using the so%tware(
This so%tware can handle single tooth restoration+ crowns# inlays 7%illings8# onlays 7$artial crowns8# and veneers( A%ter the design is com$lete# the data is transmitted via a wireless radio signal to the C?CS Milling /nit(
Diamond coated instruments mill a ceramic bloc6 to re$roduce the design(
This is done during a single a$$ointment using Com$uter Aided Design,Com$uter Aided Manu%acture 7CAD,CAM8(
htt$+,,www(sirona(com,ecomaU<,inde!($h$VsiteK0)?OA.COM.cadcam.systems
Ceramic Materials
Lhen creating C?C restorations# you can choose %rom %elds$ar ceramics# glass ceramics and high3$er%ormance $olymers(
They are biocom$atible# clinically tested# durable and metal3 %ree( Problems due to corrosion and incom$atibility can be virtually ruled out(
The ceramic materials %ul%ill stringent standards in terms o% %racture toughness# abrasion# aesthetics and machinability( 0irona has develo$ed its own range o% machinable ceramic bloc6s %or the C?C and in<ab CAD,CAM systems(
 
0li$ Casting
 A liquid clay body 7a sli$8 is $oured into a $laster mold and allowed to %orm a
layer on the inside cavity o% the mold(
)n a solid cast mold# ceramic ob*ects li6e handles and $latters are surrounded by
$laster on all sides with a reservoir %or sli$# and are removed when the solid
$iece is held within(
For a hollow cast mold# once the $laster has absorbed most o% the liquid %rom
the outside layer o% clay the remaining sli$ is $oured o%% %or later use(
The cast $iece is removed %rom the mold# trimmed and dried( This $roduces a
green $iece that is then %ired# with or without decoration and gla'e(
The technique is suited to the $roduction o% com$le! sha$es# and is commonly
used %or toilets# basins# %igurines and tea$ots( The technique can also be used
%or small scale $roduction runs(
2 solid com$onent hollow com$onent
$our sli$
into mold
ceramic clay body is %ormed into a use%ul sha$e(
 Mill 7grind8 and screen constituents+ desired
$article si'e(
 
 ; shrin6age (
Drying and Firing
Drying too %ast causes sam$le to war$ or crac6 due to non3uni%orm shrin6age
wet body $artially dry com$letely dry
Firing+   33 heat treatment between
@3HC
%rom clay and %lu! ; %lows
between 0iO- $articles( 7Flu!
lowers melting tem$erature8(
  m    i  c   r  o   g   r  a   $
   h   o
Clay is ine!$ensive(
%aolinite is a clay mineral with the chemical com$osition Al-0i-O27O8H(
)t is a layered silicate mineral# with one tetrahedral sheet lin6ed through o!ygen atoms to one octahedral sheet  o% alumina octahedra(
Lhen water is added to clay# water molecules %it between layered sheets# reducing degree o% van der Laals bonding5 7Can shear along vdL bonds more easily8(
Lhen e!ternal %orces are a$$lied# clay $articles are %ree to move $ast one another# becoming hydro$lastic(
 Adding water to clay enables e!trusion and sli$ casting(
1ao$ectate# $a$er# $i$es 7smo6ing8(
 )sostatic 7hydrostatic8 com$ression 3 $ressure a$$lied
by %luid 3 $owder in rubber envelo$e
 ot $ressing 3 $ressure R heat(
Microstructure o% a barium magnesium
tantalate 7BMT8 ceramic $re$ared using
com$action and sintering( 7Courtesy Heather
Shivey (8
com$ositions(   Powder 7$lus binder8
mold(
 
 0intering occurs during %iring o% a $iece that has been
$owder $ressed# $owder $articles coalesce and $ore si'e is
reduced(
 Ty$ically# ceramics with a small grain si'e are stronger  than
coarse3grained ceramics(
 Finer grain si'es hel$ reduce stresses that develo$ at grain
boundaries due to anisotro$ic e!$ansion and contraction(
 
 
Ta$e Casting Ta$e casting 3 A $rocess %or ma6ing thin sheets o% ceramics
using a ceramic slurry consisting o% binders# $lastici'ers# etc(
The slurry is cast as ta$e with the hel$ o% a blade onto a $lastic
substrate( /sed %or integrated circuits and ca$acitors
0li$ K sus$ended ceramic $articles R organic liquid
 
%ormed by mi!ing cement
having varied and com$le!
sha$es(  ardening $rocess+ hydration
mi! clay and lime3bearing
minerals calcine 7heat to HC8 grind into %ine $owder 
Ceramic Fabrication Methods 3 Cementation