Modul2 Pendahuluan Proses Produksi - Casting

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Lecture No 4 1

Goal of Lecture

• To provide an overview of material formingand shaping process fundamentals

• To understand the important factors incasting metals – Physical

– Operational – Economics



Lecture No 4 2

Some Useful Links

• American Foundryman’sSociety – http://www.afsinc.org

• American MetalcastingConsortium – http://amc.aticorp.org

• Cast Metals Institute – http://www.castmetals.org

• North American Die CastingAssociation – http://www.diecasting.org

• Ductile Iron Society – http://www.ductile.org

• Ferroalloys Association – http://www.amc.scra.org/tfa

• National Center for

Excellence in Metalworking – http://www.ncemt.ctc.com

• Nonferrous FoundersSociety – http://www.nffs.org

• Steel Founders of America – http://www.sfsa.org

http://www.afsinc.org/

http://www.sfsa.org/

http://www.nffs.org/

http://amc.aticorp.org/

http://www.amc.scra.org/tfa

http://www.ductile.org/


http://www.castmetals.org/






Lecture No 4 3

Casting Processes• Some Web pages of casting sources

– Some cast houses• http://www.solidiform.com/

• www.reliance-foundry.com/

• http://www.qesc.com/third.htm – this has some nice images of large castings

– The future of casting• http://www.oit.doe.gov/metalcast/

http://www.oit.doe.gov/metalcast/

http://www.diecasting.org/

http://www.ncemt.ctc.com/thrustAreas/index.html



http://www.solidiform.com/



Lecture No 4 4

Casting

• The conversion of raw materials into usefulshapes using phase transformations

• One of the first steps in converting rawmaterials into useful products

• Applicable to most materials – Metals – Ceramics – Plastics – Glass

• Also includes mixtures – Ceramic slips and slurries



Lecture No 4 5Casting - a Form of Phase ChangeForming

• The use of changes of phase to createintricate shapes – Form the shape in the liquid state in a mold or

container• Molten metals

• Monomer solutions• Slips• Slurries

• Change the liquid into a solid• Remove heat

• Remove suspending liquid• Initiate a reaction – apply heat – inject reactants – irradiate with photons



Lecture No 4 6Other Forms of Phase ChangeForming

• Plasma spraying• Spray forming• Stereolithography

– http://www.solutionsin3d.com/main.htm – http://www.protocam.com/art_to_part/fslide2.htm

• Selective Laser Sintering – http://lff.me.utexas.edu/sls.html

• Fused deposition modeling – http://nasarp.msfc.nasa.gov/fdm.html

• Single crystal growing• Inorganic glass forming• Liquid metal jet printing

– http://arri.uta.edu/lmj/

http://www.reliance-foundry.com/

http://www.reliance-foundry.com/

http://nasarp.msfc.nasa.gov/fdm.html

http://lff.me.utexas.edu/sls.html

http://www.protocam.com/art_to_part/fslide2.htm

http://www.solutionsin3d.com/main.htm



Lecture No 4 7

Casting Fundamentals

• Casting advantages – High shape complexity with internal cavities – Large shape size and variety – Wide variety of materials – Ease of production

– Variety of materials that can be cast – Close tolerances (some processes) – High surface finish (some processes) – Excellent mechanical properties (some

processes)

– Economics (for some lot sizes)

Kalpakjian pp 262-263



Lecture No 4 8


• Casting disadvantages – High setup costs – Low tolerances (some processes) – Low surface finish (some processes) – Porosity (some processes)

– Inhomogeneities (some processes) – Poor mechanical properties (some processes)



Lecture No 4 9


• Overall Process: – Make mold – Pour in liquid – Cool/solidify – Remove shape from mold



Lecture No 4 10

Types of Casting

• Molten materials which solidify on cooling – Metals, ceramics, glasses

• Liquids which solidify by reactions with light,activators/hardeners or moisture – Plastics

• Slurries which solidify by the extraction of thesuspending medium (usually water) – Ceramics



Lecture No 4 11Casting Fundamentals for MoltenMaterial

• Factors affecting solidification characteristicsfrom the molten state – Fluidity

• Flow of molten material into the cavity

Kalpakjian p 265



Lecture No 4 12

Fluidity of Molten Metal

• Fluidity is dependent on: – Characteristics of the fluid – Casting parameters



Lecture No 4 13Fluidity - Characteristics of thefluid

• Basically, Fluidity is the ability of the liquid toflow into the mold


• Viscosity and sensitivityto temperature

• Surface tension• Inclusions• Freezing range

Fluidity



Lecture No 4 14

Theory of Fluid Flow

• Theory has three components: – Bernoulli's theorem – Continuity law – Laminar vs turbulent flow




Lecture No 4 15

Bernoulli's theorem

• Where: h is the elevation above a reference plane, p is the pressure atthat elevation, v is the velocity of the liquid at that elevation, r is thedensity of the liquid and g is the gravitational constant

– For zero velocity, pressure is proportional to height and density – For a constant height, Velocity is proportional to the square root of

pressure – etc

h + ---- + ---- = constantp

rg

v 2

2g



Lecture No 4 16

Continuity Law

• For an incompressible liquid:

• Av = constant, the flow rate

• Where A is the cross sectional area and v is the velocity



Lecture No 4 17

Laminar vs Turbulent Flow

• Laminar flow is preferred – Reynolds number less than 2000

• Turbulent flow (Re >20,000) can cause airentrapment and dross (oxide) formation

– results in defects



Lecture No 4 18

Practical Fluid Flow

• Pouring basin – where the molten metal enters the mold

• Gating system – connects the pouring basin to the rest of the

mold through

• Sprue connects the pouring basin to the runners• Runners carry the molten metal to the mold

• Risers – act as reservoirs to supply molten material as

it solidifies and shrinks



Lecture No 4 19

Kalpakjian p 275

Casting Parameters AffectingFluidity

• Mold design• Mold material• Mold surface characteristics

• Degree of superheat• Rate of pouring• Heat transfer






– Heat transfer – During solidification and cooling

Kalpakjian p 265



Lecture No 4 21

Heat Transfer

• Very complex phenomenon• Very simple process

– A cold mold extracts heat from the meltcausing it to solidify

• Critical to design of mold• Can compute a relative time for solidification

Kalpakjian p 275



Lecture No 4 22

Heat Transfer - Solidification Time

• Proportional to the square of the volume/ surface area ratio – A sphere will have a much longer solidification

time than a complex shape of the same volume



Lecture No 4 23

Effect of Cooling Rate

– Rate of cooling critical for the structure of thematerial and hence its properties

• Slow cooling (~100K/s) gives large grain sizes

• Fast cooling (~10 k/s)gives small grain sizes

• Very fast cooling rates (>10 K/s)produce amorphousmaterials

– Implications:-• Should design artifact to be thin and not massive

• Require "chills" to control cooling rate




• Factors affecting solidification characteristicsfrom the molten state

– Fluidity• Flow of molten material into the cavity

– Heat transfer• During solidification and cooling

– Solidification

Kalpakjian p 265



Lecture No 4 25

Solidification Effects

• This is where the material comes important – Plastics

• Not as critical as for metals

– Semiconductors• Specialty crystal growing

• Single crystal so no microstructures

– Glass• No microstructure




Lecture No 4 26

Solidification Effects - Metals

• Molten metal solidification events depend onthe type of material – Pure metals

– Alloy



Lecture No 4 27

Solidification of Pure Metals

• Solidification occurs from the mold walls tothe center in a plane front

• Grains tend to be equiaxed and grow outwardfrom the mold wall in a columnar structure

• Nucleation agents can cause a moreequiaxed structure (more uniform grains andsize distribution)



Lecture No 4 28

Crystallization Phenomena

• Kalpakjian p 267



Lecture No 4 29

Solidification of Alloys

• Eutectics behave similarly to pure metalsbut• Cast grain structure depends on phase

diagram



Lecture No 4 30

Solidification of Alloys

• Alloys with liquidus and solidus temperatures have aphysical “mushy zone”

• “Mushy zone” has solid particles and liquid co-existing• Solid particles tend to be dendritic (tree form) in

nature and grow from the mold wall• Microstructure highly dependent on cooling rate• Freezing range is the difference between the liquidus

and solidus temperatures• Ferrous alloys tend to have small freezing ranges• Aluminum and magnesium alloys tend to have wide

freezing ranges



Lecture No 4 31

Kalpakjian p 120

Copper-Nickel Phase Diagram



Lecture No 4 32Why is solidification so importantfor metals?

• The solidification events determine themicrostructure of the product: – Grain size – Grain distribution

– Grain morphology – Grain boundaries – Grain composition – Porosity content and type



Lecture No 4 33

More Crystallization Phenomena



Lecture No 4 34Influence of Grain Size onMicrostructure

• Grain size• Microporosity

Kalpakjian p 269

Cracking tendency

Strength

Ductility



Lecture No 4 35

Structure-Property Relationships

• Slow cooling - uniform composition

• Normal cooling - microsegregation and Macrosegregation

• Microsegregation – Segregation of alloying elements within the

grains or dendrites – Dendrites are the columnar grains that

typically grow from the mold surface – Dendrite surface has higher concentration of

alloying elements than core

• Macrosegregation – Segregation of alloying elements across the

casting itself.



Lecture No 4 36

Structure-Property Relationships

• Macrosegregration – Normal

• Lower melting constituents driven away from themold wall

– higher concentration at center

– Inverse• melt enters the cavities among the dendrites formed

at the surface

– Gravity• Heavy elements sink to the bottom

• Macrosegregation gives rise to poormicrostructures



Lecture No 4 37

Avoidance of Macrosegregation

• Use – Nucleation agents – Create more grains by mechanical means

• Rheocasting - stir the metal while it is in the mushyzone

• Vibration

• Electromagnetic stirring



Lecture No 4 38

Solidification Effects - Shrinkage

• The metal shrinks as it cools – in the melt – as it solidifies as a solid (largest)

Kalpakjian p 279

Aluminum 6.6%Carbon Steel 2.5-3%

Copper 4.9%Gray iron -2.55

Volume Solid Contraction of some metals:



Lecture No 4 39Impact of Shrinkage on MoldDesign

• Dimensions of mold• Molds must be constructed to be larger than

the final product because the metal shrinksas it cools

– Patternmakers ruler• Warpage due to differential shrinkage• Defects due to induced stresses• Porosity

L N



Lecture No 4 40

Solidification Effects - Defects

• Defects caused by – materials – part design – processing techniques

• No simple answers


L N 4 41



Lecture No 4 41

Defect Classes• Projections

– fins, flash, swells (massive), rough surfaces• Cavities

– internal, exposed, blowholes, pinholes

• Discontinuities

– cracks, cold and hot tearing, cold shuts• Defective surface – folds, laps, scars, adhering sand, oxide scale

• Incomplete casts – insufficient metal, leaky molds

• Incorrect dimensions or shape – improper shrinkage allowance, warping, etc

• Porosity – T

See Kalpakjian pp 279-281

L t N 4 42



Lecture No 4 42

Porosity

• A special kind of cavity

• Caused by shrinkage or gases• Detrimental to the ductility of the metal, the

surface finish and pressure integrity of thepart

L t N 4 43



Lecture No 4 43

Shrinkage Porosity

• Caused by differential cooling

• Thin sections cool faster than thick sectionsleading to too little material in the thicksections

• When the thick sections begin to solidify,

porosity develops• Mold designers avoid this by the use of chills

and proper flow channels and riser placement

Lect re No 4 44



Lecture No 4 44

Gas Porosity

• Liquid metals have greater solubility for gases

than solid metals• Any gas in the melt appears as spherical

cavities• Melt treatment must include various

degassification processes• Can also have gases arising from reactions

(melt - mold)

Lecture No 4 45I t f ll th f t ld



Lecture No 4 45Impact of all these factors on molddesign

• Very complex,• Empirical• Best left to experts• There are some general guidelines, see later

Lecture No 4 46C ti F d t l f M lt






– Heat transfer effects• During solidification and cooling

– Solidification effects – The type of mold material

Kalpakjian p 265

Lecture No 4 47



Lecture No 4 47

Influence of the Mold Material

• Mold material impacts: – The heat transfer rate – The surface finish – The number and hence grain size of the

microstructure

• Selection of the mold material is stronglyinfluenced by the process

Lecture No 4 48C ti P f Li id



Lecture No 4 48Casting Processes for LiquidMetals

• There are two classes of processes: – Ingot casting - simple shapes for subsequent

processing – Net shape casting

Lecture No 4 49Th C ti P f R lli



Lecture No 4 49The Casting Process for Rollingand Extrusion

• Semicontinuous casting of ingot – No complete mold – Bottom of mold moveable – Skin forms the mold

Melt

Water

in

Water

out

Moltenmetal

Solidmaterial

Lecture No 4 50



Lecture No 4 50

Ingot Cross-Section

Extrusion IngotRolling Ingot

• Disadvantage of ingots – Often need scalping to provide good surface

finish – Require energy to homogenize/reheat – Handling 20-40 ton slabs is difficult – It is an extra step which adds costs

Lecture No 4 51



Lecture No 4 51

Continuous Casting

– Remove bottom of mold and continually pullslab out of mold - a continuous billet

– Advantages• Lowers cost

• Continuous production

– Disadvantage• Difficult to control

• Grain structure of cast material not entirelyeliminated because the hot deformation is less

• Difficult to change material

• Difficult to start and stop

Lecture No 4 52



Lecture No 4 52

Continuous Casting Equipment

Kalpakjian p 160

Lecture No 4 53



Lecture No 4 53

Net Shape Casting Processes

• Major Categories

– Expendable mold• made of sand, plaster, ceramics with binders

• mold broken up to remove cast shape

– Permanent mold• used repeatedly

• designed for ease of casting removal

• typically fabricated of high temperature metals

• typically provide higher quality castings because ofthe high rate of cooling

– Composite mold• uses the advantages of both expendable and

permanent molds

Lecture No 4 54



Lecture No 4 54

Expendable Molds

• Sand Casting

• Lost Foam – Expendable pattern casting

• Plaster Mold• Ceramic Mold

– Cope and drag investment casting• Vacuum casting

Lecture No 4 55



Sand Casting

• Most ancient process

• Still most prevalent• ~15 million tons produced each year• Typical products include:

– machine tool bases, engine blocks, cylinder

heads, pump housings

Lecture No 4 56



Sand Casting

• Advantages – Can be applied to all commercially used metals – Can obtain intricate shapes – Can apply to large objects

– Is economical for small production runs – Equipment costs are generally low

• Disadvantages – Surface finish depends on the mold material – Dimensional accuracy not as good as other

casting processes

Lecture No 4 57



Sand Casting Process

• Create pattern of desired shape

• Place in box of sand to create an imprint (mold)• Incorporate a gating system• Fill imprint with molten metal• Solidify and cool• Break away the mold and remove casting

Kalpakjian Ch 11.3

Lecture No 4 58



The Sand Casting Process

Kalpakjian p 298

Lecture No 4 59



Overall Shrinkage

Metal PercentGray Cast iron 0.83-1.3

White Cast Iron 2.1

Malleable cast iron 0.78-1.0Aluminum alloys 1.3

Magnesium 1.3

Yellow brass 1.3-1.6

High manganese steel 2.6

Lecture No 4 60



The Sand

• Mostly silica sand (silicon dioxide)

– Naturally bonded or bank sands – Synthetic or lake sand preferred because its

composition can be controlled more accurately

• The factors

– Fine round grains give smooth surfaces – Permeability allows gasses to escape – Good collapsibility to avoid defects in the

casting

Lecture No 4 61



Types of Sand Molds• Green sand molding

– Least expensive – Poor dimensional accuracy – Skin drying improves

• strength,

• dimensional accuracy

• surface finish

• Cold Box molding – Uses sand plus binders – Stronger molds

– Dimensionally more accurate• No-bake molding – Sand plus resins – Best strength, dimensional accuracy and finish

Lecture No 4 62



Sand Mold Components

• Flask (container)

• Mold itself – Cope on top – Drag on bottom

• Pouring basin or cup

• Sprue• Runner system• Risers• Cores

• Vents

Lecture No 4 63



Patterns

• Patterns are used to mold the sand to the

required shape• May be made of wood, plastic or metal• Material selection depends on

– casting size and shape

– required dimensional accuracy – quantity to be produced – molding process

Lecture No 4 64



Cores

• Used to form interior cavities• Really just another specialized word for a

pattern

Lecture No 4 65



Sand Molding Machines

• Purpose is to compact the sand around the

pattern – Hand hammering – Squeezing – Jolting

– Vertical flaskless molding (automated) – Sandslinging – Impact molding – Vacuum molding


Lecture No 4 66



Shell Mold Casting

• A mounted pattern is coated with a partingagent and clamped to a box containing finesand with a binder

• Box is turned upside down to allow the sandto coat the pattern

• Assembly is placed in an oven to allow thebinder to act and the sand hardens aroundthe patterns

• Two half shells made by this method areclamped together to form the mold into whichthe molten metal is poured

Lecture No 4 67



Shell Mold Casting

• Advantages – Can produce casting with sharper corners,

smaller projections, and thinner walls thangreen-sand molds

– Is somewhat lower in cost than other sandcasting techniques

– Produces casting with excellent surface finish – Process can be automated

• Disadvantages

– Unless properly vented, can have severe gasentrapment problems

Lecture No 4 68



Lost Foam Process

• The pattern is formed from polystyrene andthe sand is formed around it.

• On pouring the molten metal into the mold,the polystyrene evaporates and is replaced

by the melt• It is probably one of the most important

process for the ferrous and non-ferrousmetals industry

– Particularly important for the automotiveindustry.

Lecture No 4 69



Lost Foam Process

• Advantages

– A relatively simple process – No parting lines – Flasks or containers can be inexpensive – Requires minimal finishing operations – Can be automated – Can be used for long production runs – Complex patterns may be made by bonding

polystyrene components together

• Disadvantages

– Fluidity is lower than in conventional sandcasting because of large temperaturegradients

Lecture No 4 70



Plaster Mold Casting

• In this process the mold is made of plaster ofparis instead of sand

• The rest of the process is similar to sandcasting in that the two halves of the mold are

clamped together and the molten metalpoured in

• Often referred to as "precision casting"

Lecture No 4 71



Plaster-Mold Casting

• Advantages – Slower cooling gives a more uniform grain

structure and less warpage – Can produce casting with fine details and good

surface finish – Casting can have wall thickness as low as 1

mm – Casting has high dimensional accuracy

• Disadvantages

– Can only be used for Aluminum. Magnesium,zinc and some copper based alloys because ofthe max temperature capability of the mold

Lecture No 4 72Investment Casting



Investment Casting(Lost wax)

• Very old process• Pattern made by injecting molten plastic or wax into a

metal die.• This pattern is then assembled onto a "tree" with

several patterns• This tree is dipped into slurry of refractory material

and coated with it• This mold is then dried and heated to melt the wax

which then runs out leaving the cavity.• The mold is then heated to ~1000oC to "fire" the

refractory and bond it into a solid• The molten metal is poured in, cooled, and the moldbroken to remove the castings

Lecture No 4 73

I C i P



Investment Casting Process

Kalpakjian p 306

Lecture No 4 74

I C i



Investment Casting

• Advantages – Wide range of sizes possible – Intricate shapes possible – Wax can be reused – Good surface finish – Close tolerances – Applicable to a wide variety of metals and

alloys

• Disadvantage

– Molds require careful handling because theyare brittle

Lecture No 4 75

P M ld C i



Permanent Mold Casting

• Molds made in two halves from cast iron,

steel, bronze, graphite or refractory hardalloys

• Surfaces coated with refractories to increasedie life, control heat transfer and help

separate casting from mold

Kalpakjian Ch 11.9

Lecture No 4 76

P t M ld C ti



Permanent Mold Casting

• Advantages

– Good surface finish – Close tolerances – Uniform mechanical properties – Fine details – Thin walls – High production rates – Automated version have low labor costs – Large size range (few gms to >=100kgs)

• Disadvantages

– High equipment costs – Not economical for small production lots – Cannot do intricate shapes

Lecture No 4 77

T f P t M ld C ti



Types of Permanent Mold Casting

• Gravity feed

• Pressure-casting – Die casting

• Hot chambers

– Cold chambers – Insert molding (cast in place inserts) – Centrifugal Casting – Squeeze casting – Semisolid metal working (forging in the slushy

state)

Lecture No 4 78Die Casting



Die Casting(Pressure Die Casting)

• Molten metal is forced into the die at highpressure (up to 100ksi)

• Two basic types of machines – Hot chamber

– Cold chamber• Typical parts are carburetors, motors,

appliance components and hand tools• Size ranges from 90 gm to 25 kg

Lecture No 4 79

Di C ti



Die Casting

• Hot Chamber – The chamber where the hot molten metal is

kept is next the die machine and automaticallyfills the "shot" chamber from which it isinjected under pressure into the mold

• Cold Chamber – The molten metal is delivered via a ladle to the

shot chamber from which it is injected into theinjection machine.

• These machine are very similar to plasticinjection molding machines but have to beable to handle higher temperatures.

Lecture No 4 80

H t Ch b Di C ti



Hot Chamber Die Casting

Kalpakjian p 313

Lecture No 4 81

Di C ti



Die Casting• Advantages

– Multiple dies allow higher production rates – Thin wall, intricate parts – Fine surface detail possible – High production rates with automated

machines

– Inserts such as fasteners may be die castintegrally

– Good dimensional accuracy – Fine grained, high strength skin results

• Disadvantages – Die costs are high – Clamping force to keep the two halves of the

die together ranges from 25 to 3000 tons

Lecture No 4 82

Casting Practices



Casting Practices

• Casting practices are the techniques,methods and operations used in casting.

• It includes things like safety, fluxes, masteralloys, furnaces,. All of which contribute to

producing a quality part in a safe manner• Safety is extremely important in a cast house

because molten metal is very dangerous

Lecture No 4 83

Safety in Casting



Safety in Casting

• Concerns

– Splashing of molten metal – Fumes from the molten metal – Dust from the sand – Fuels for the furnace, their control and proper

operation of the equipment supplying them to

the furnace – Water

• Water and molten metal is extremely explosive sincethe high temperature of the melt rapidly converts it tosteam

– Handling of fluxes which can absorb water – Faulty equipment especially cracks in molten

metal containers such as ladles

Lecture No 4 84

Fluxes and Slags



Fluxes and Slags

• Fluxes are inorganic compounds that – refine the molten metal by removing dissolved

gases and impurities – perform other functions

• Prevent oxidation (aluminum casting)

• Cleaning

• Wall cleaning

• Slag forming

• Fluxes are mostly compounds of chorides,fluorides and borates of aluminum, calcium,

magnesium potassium and sodium.• Some fluxes form an insulating cover for the

melt to prevent oxidation. They form Slags

Lecture No 4 85

Master Alloys



Master Alloys

• Really a misnomer• They are alloys of those alloying elements

required for a particular alloy which do notreadily dissolve in the melt

• By alloying these elements in a low meltingalloy, they can be more readily dissolved intothe melt.

Lecture No 4 86

Melting Furnaces



Melting Furnaces

• Most common types are:

– Electric Arc• have higher melting rate and lower pollution than

most others

– Induction• Coreless induction furnaces provide excellent mixing

• Cored induction furnaces typically used forsuperheating and holding furnaces

– Crucible• heated by oil, gas or electricity

• may be stationary, tilting or moveable

– Cupola• Large furnaces for making steel with layers of iron,

coke and flux

• Operate continuously

Lecture No 4 87

Single Crystal Casting



Single Crystal Casting

• Creates single crystals for specialapplications – Jet engine blades - superalloys – Semi-conductor material

• Chrochalsky process

Lecture No 4 88

Design Guidelines for all Casting



Design Guidelines for all Casting

• General Design Principles

– Avoid sharp corners, angles and fillets – Avoid sharp section changes (blend smoothly) – Avoid large flat areas (use ribs and serrations) – Allow for shrinkage – Design parting line in appropriate location – Design in draft angles (for release of casting

from mold) – Do not ask process to deliver higher

tolerances than it can deliver

– Allow extra material for finishing – Consider stress relieving – Enlist the help of a casting company

Kalpakjian Chapter 12

Lecture No 4 89

General Casting Economics



General Casting Economics

Cost ProductionProcess Die Equip Labor Rate (Pc/hr)Sand L L L-M <20Shell-mold L-M M-H L-M <50

Plaster L-M M M-H <10Investment M-H L-M H <1000Permanent mold M M L_M <60Die H H L-M <200

Centrifugal M H L-M <50

Kalpakjian p 347

Lecture No 4 90

Other forms of Casting



Other forms of Casting• Plastics

– solidification occurs by a reaction• with added hardener/activator

• with moisture in the air

• Ceramics – Like molten metals but at much higher

temperatures• Only simple shapes possible

– Slurry casting• Powder ceramic mixed with water to form a fluid

which is poured into the mold

• Mold is porous and extracts the water• Cast body must be dried and fired at high

temperatures to obtain reasonable strength

Lecture No 4 91

Conclusions



Conclusions

• Casting is a very flexible process with a lot of

advantages• BUT• It is complex and has a lot of variables• Enlist an expert before you commit you

design to casting

Lecture No 4 92

Summary



Summary

• Phase change forming - Casting

– Processes• Ingot casting

• Shape casting – Expendable mold

– Permanent mold

– Composite nold

Documents

Modul2 Pendahuluan Proses Produksi - Casting