Primary shaping - Casting - RWTH Aachen University nucleation at side walls ... Classification of...

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© WZL / IPT

Primary shaping - Casting

Manufacturing Technology II

Lecture 1

Laboratory for Machine Tools and Production Engineering

Chair of Manufacturing Technology

Prof. Dr.-Ing. F. Klocke

© WZL / IPT Seite 1

Structure of the lecture CastingIntroduction: Variety of applications

Basics of casting

Production sequence at casting

Production of casting patterns

Production of consumable moulds and cores

Casting processes

Case studies: Simulation during design and production

Case study: Rapid-Prototyping used at production of casting patterns

Comparison of costs

Summary

2


Introduction: Variety of applications- Survey of materials for casting and application examples

Basics of casting




Casting processes



Comparison of costs

Summary

Structure of the lecture Casting


copper

aluminium

ferrousmaterials

chilled cast iron

grey cast iron

technical pureiron (C < 0,1%)

steel(0,1% C < 2%)

cast iron(2% < C < 4,5%)

white cast ironwhite iron white-heart

malleablecast iron

black-heartmalleablecast iron

lamellar

globular

nonferrousmaterials

Survey of materials for casting

others(magnesium,

tin, etc.)

annealedcast iron

3


The golden sun wagon of Trundholm, Seeland

Trundholm, Højby, Holbæk, Dänemark

14th cent. b. chr. bronze and goldlength: 59,6 cm

source: Nationalmuseum, Kopenhagen

Sun wagon - Early bronze period


Production of high-volume components through casting

Abrasive blasting process of a 16-cyl.- motor unit

made of GJL-300 (CrCu-alloyed) in a completely encapsulated

sand blast chamber with dust extraction set

source: Siempelkamp, Krefeld, konstruieren+giessen 3/94

4


Production of small-volume components through casting

Precsion casting component foran surgical instrument

material: G-X 10 CrNi 18 8 (1.43.12)dimension: ∅ 7 x 54 mm

weight: 10 g

source: Hitzbleck


source: Honsel

process: magnesium diecasting

material: EN-MC MgAl6Mn

thickness ofwalls: 2 - 2,5 mm

weight: 3,5 kg

Prototype of a cast car door made of magnesium

5


source: Eisenwerke Brühl

Motor unit- AUDI 059 2.5 L TDI: Audi A6, A4, A8, Passat

Cast part Part with machined surfaces


Boeing Instrument Panel - Aluminium investment casting

source: Tital

Dimensions1700x600x1200 mm

6


Structure of the lecture CastingIntroduction: Variety of applicationsBasics of casting

- Cooling down the liquefied material- Crystallization and crystal growth - directional

solidification- Basics of solidification- Casting simulation: Example


Production of casting patternsProduction of consumable moulds and coresCasting processesCase studies: Simulation during design and productionCase study: Rapid-Prototyping used at production of casting patternsComparison of costsSummary


Cooling curve of pure iron resp. Fe-C (723°C)

Body-centeredcubic (b.c.c.)α- and γ-iron

Face-centeredcubicδ-iron

°C

15361392

911769723

210

molten mass

γ-Eisen, kubisch-raumzentriert

δ-Eisen (Austenit),kubisch-flächenzentriert

α-iron (ferrite), paramagnetic,body-centered cubic (b.c.c)

α-iron (ferrite), ferromagnetic

perlite

Fe3C (Zementit)ferromagnetisch6,67%C

source: Verlag Moderne Industrie - Temperguss

Cooling down the liquefied material: Changing crystal latticeElementary cell of thecrystal system

7


Crystallization and crystal growth

art-own nuclei foreign nuclei(e.g. contamination

Crystal growth

no. of nuclei direction ofheat-removal

rate of cooling

crystal size,crystal form

Crystal growth 180° opposite to the heat-removal

Crystallization nuclei


exclusivelyglobulites

Crystal nuclei are uniformly distributed

exclusivelyfringe crystals

Primary nucleationat side walls

Transition between both extreme examples

fringe crystals+

globulitessource: Spur, Handbuch der Fertigungstechnik, S.60

Formation of cast structure through crystallization

8


globuliticalsolidification

fringe crystalsolidificaton

monocrystallinesolidification

schematiccast structure

Directional a.monocrystalline solidification at turbine blades

source: Thyssen


200 µm

longitudinal transverse

longitudinal transversal

Cast structure after polycrystalline and directionalsolidification

200 µm 50 µm

1. polycrystalline

50 µm200 µm200 µm

2. Directional solidif.

9


3. monocrystalline solidificated

identical in longitudinal and transverse direction

Cast structure after monocrystalline solidification

200 µm 50 µm


Structure of the lecture CastingIntroduction: Variety of applicationsBasics of casting

- Cooling down the liquefied material- Crystallization and crystal growth - directional

solidification- Basics of solidification- Casting simulation: Example

Production sequence at castingProduction of casting patternsProduction of consumable moulds and coresCasting processesCase studies: Simulation during design and productionCase study: Rapid-Prototyping used at production of casting patternsComparison of costsSummary

10


number of nuclei

rate of cooling

formation ofcoarse grain

formation offine grain

coarse grain

fine grain

-

+

tensilestrength

- +

deformationresistance

hardness creep rate

-

+

-

+

-

+

directionaldependance

+

-

Grain size in the cast structure - Coarse grain and fine grain


Solidification of a hypoeutectique alloy

tem

pera

ture

T

percent in weight B

bd

S

a+SS+ß

a

Legend

a: alloying composition

b: primary crystallization

c: eutectic crystallization

d: eutectic alloy

a

c

source: Spur, Handbuch der Fertigungstechnik, S.60

11


smooth wallsolidification

rough wallsolidification

sponge likesolidification

example: pure metals

increase of alloy content

Exogenous solidification

fest flüssig

Solidification process - Crystallization at side walls

source: Engler, in: Spur, Handbuch der Fertigungstechnik

solid liquild


pulpysolidification

shell formatingsolidification

Endogenous solidification

source: Engler, in Spur, Handbuch der Fertigungstechnik, S.61

Solidification process - Crystallization inside the melt

12


inititial state

side wall movement

metal wall movement

Interface between metaland forc

concave planar

legend: a: die cavity b: die c: liquid metal (arrows show the direction of the movement)

Wall movement during solidification of cast iron

source: Spur, Handbuch der Fertigungstechnik, S. 75

konvex

a b

c


mould filling capacity

fluidity

feeding capacity

heat checking

Shrinkagecavitation

temperature

spez

ific

volu

me

32

1

temperature

spez

ific

volu

me

32

1

Shrinkage behaviour of pure metalsand eutectic alloys

Shrinkage behaviour of non-eutectic alloys

2 3

1

Casting properties - shrinkage cavitation

liquidshrinkage

solid

liquid

solidificationshrinkage

shrinkagecavity

so lid shrinkage

13


mould filling equation of continiuity:

Navier-Stokes-equation:

heat transport:solidification

with

source: konstruieren+giessen 23 (1998) Nr.3

Basic equations of heat and mass transfer

0)( =⋅vdiv rρ

( ) vpgradgvdivvv rrrr∆⋅++⋅=⋅⋅+⋅ µρρρ )(

[ ] [ ].

)()( QTgraddivTgradvTcp +⋅=⋅+⋅ λρ r

ngravitatiogvelocityvpressurepdensity

====

r

ρ

/.

heatofsourceQ

ductivitythermalconetemperaturT

heatspezificcitykineticvisµ

p

=

==

==

λ

cos


Contribution to casting simulation - Cast part

source: Magma

14


source: Magma

Contribution to casting simulation - Simulation of mould filling


Introduction: Variety of applications

Basics of casting

Production sequence at casting- Classification according to DIN 8580- Definitions of moulding and casting processes- The route to the structural cast part



Casting processes



Comparison of costs

Summary


15


Primary shaping

Primary shaping out of the gaseous or

vapour state

Primary shaping outof the liquid, pulpy or paste like state

Primary shaping outof the ionized statethrough electroly-

tical deposition

Primary shaping outof the solid, granular

or powdery state

casting inconsumable

moulds

casting inpermanent

moulds

permanentpatterns

consumablepatterns

powder metallurgy

lecture 2

source: DIN 8550

Classification of primary shaping methods acc.


Definitions: Moulding and casting processes

moulding process all processes for the production of consumable moulds, which arenecessary for the absorption of the liquid metal

static casting (gravity casting)

dynamic casting

movement of the mould

movement of the melt

consumable mould

permanent mould

sand casting

gravity die casting

movement of the mould and melt

centrifugal casting

pressure die casting

continuous castingsource: Spur

casting process principle of mould filling, e.g. gravity casting, pressure diecasting, ....

16



Basics of casting

Production sequence at casting- Classification according to DIN 8580- Definitions of moulding and casting processes- The route to the structural cast part



Casting processes



Comparison of costs

Summary


legend:

a

b

c

d

e

f g i

h

j k l

mn

source: Spur

The route to the structural cast part

a: cast patternb: hand mouldingc: machine mouldingd: core setting

e: core mouldingf: setting the top box of

the mouldg: castingh: melting

i: shaking outj: casting cleaning roomk: machining of cast partl: shipping

m: sand bunkern: sand plant

17


• Schmelzbetrieb

Example of application: Moulding shop

source: Gießerei Fronberg



Example of application: Hand core moulding

18


unloading the cores out of the core shooter core setting

source: Laempe

Example of application: Automatisation at core production


machining deep-hole drilling

Example of application: Machining of cast parts


19




Basics of casting




Casting processes



Comparison of costs

Summary


production of consumable moulds

production of permanent moulds

generation the most important outer sections of the die cavity includingcore marks as well as casting and feed system

setting of core marks for fixing the cores (necessary for cast parts with cavitity)

pattern-materialrequirements

resistance against- mechanical stress (compression, beat loose, unloading the model)- chemical stress (humidity, acids and bases of the binding agents, gases)- thermal stress (heating of the model plate - necessary for hardeningof the moulding material)

good machinability

high surface quality

low density

whoodmetal

plasticspolystyrene

tasks of the casting pattern

Tasks of casting pattern - pattern-material requierments

20


Milling a component of the casting patternDrawing of gearbox case cap

Production of a metal mould



Basics of casting



Production of consumable moulds and cores- Production of consumable moulds: Definitions and

example of application- Core production: Cold-Box und Hot-Box-process

Casting processes



Comparison of costs

Summary

21


mouldcategory

pattern

mouldcavity

consumablepattern

compression

mouldingmethod

split one piece

permanent moulds consumable moulds

hollow hollow solid

chemical chemical physical

smeltable gasifiable

precisioncasting

full mould-casting

dry sand-partial vacuum,

full mould-magneticmoulding

mechanical chemical physical

smectitesand-,method

cement-,waterglass-

plaster mouldcastings

air-Set-,Hot-Box,

Cold-Box-shell mould-

casting

Classification of methods for producing consumable moulds

source: Spur


Overview of mould materials for consumable moulds

granular basis moulding material(e.g. silica sand)

bond clay additives

waterclay-bonded

moulding materials62%

greensand methoddry-moulded

castingchamotte

moulding method(burning process at 600-800°C)

moulding method

resin-bondedmoulding materials,

cold-curing19,5%

cement-bondedmoulding materials

12%

resin-bondedmoulding materials,

heat-curing4,8%

water glass bondedmoulding materials

20%others

5%

source: Spur

22


basis moulding materialse.g. quartz sand, zircon sand

moulding material bindere.g.silicates, artificial resins

moulding material additivese.g. dust coal and synth.

glance coal agent to reduce the wettability

moulding materials(classification acc. to binder type)e.g.: clay- or water bonded sand

moulding methodclassification according to technology,

e.g. greensand method, (cold-box) and hot-box method

part of a molde.g. core, top and bottom box of a mold, shell

moulding adjuvantse.g. moulding powder, core binder

mould coating materialse.g. blackening, mould varnish

moulding accessoriese.g. central gate, cooling fixture

final mouldsource: Spur

Terminology of mould materials for consumable moulds


Process characteristics:The loose moulding sand is filled into the mould area formed by pattern plate/pattern bolster, mouldbox and filling frame. An air current is passed through and then the mould is compacted. The air current flows through the sand from the back of the mould in the direction of the pattern andescapes through vents in the pattern plate. The air current moves the sand into the less accessibleregions of the pattern and greatly improves and optimises compaction. The final strength in the mould is built up in an after-pressing stage, using a fixed or a flexiblepressure plate, a water cushion or a multi-platen press. The magnitude of the press pressure, as wellas the pressure and duration of the air current can be controlled. This enables optimum mouldstrengths to be achieved to suit the individual application.

principleSEIATSU™ Airflow Squeeze technology

for clay-bonded sand

example of application: cast part

Production of sand moulds using the SEIATSU™-process

source: HWS – Heinrich Wagner Sinto

23




Basics of casting



Production of consumable moulds and cores- Production of consumable moulds: Definitions and

example of application- Core production: Cold-Box und Hot-Box-process

Casting processes



Comparison of costs

Summary


The cold-box process is a core production method, at which humid, pourable moulding materialis cured (baked) in very short times at room temperature in cold core boxes.

core shooting introduction of gas disposal

sand-bindermixture

core

catalyst/airor CO2

thinned acidsource: Spur

Core production using cold-box method

24


Core production using hot-box method

B: Offenes SystemA: Geschlossenes System

transport of core sand to the

coreshooting machine

core sanddressing

core shooting inin heated core box

unloadingthe core

post-cure

source: Spur

curing of mouldingmaterial

in hot die

A: closed system B: open system

legend:

a: from the generatorb: outgoing air into

exhauster or in open airc: exhausterd: coree: core box


Examples for hot-box cores on furan resin basis

single cores and assembled cores for an aluminiumsuction system of a 6-cylinder injection engine

source: Spur

25


Cores and machining allowance at cast partone piece core

unmachined cast part with core

machining allowance

finishedcast part

source: Heidenreich & Harbeck


Introduction: Variety of applicationsBasics of castingProduction sequence at casting Production of casting patternsProduction of consumable moulds and coresCasting processes

- Casting in consumable moulds with permanent patterns- Survey of different processes- Sand casting process- Shell casting process

- Casting in consumable moulds with consumable patterns- Casting in permanent moulds without patterns

Case studies: Simulation during design and productionCase study: Rapid-Prototyping used at production of casting patternsComparison of costsSummary


26


Process Hand moulding

Possiblematerials

Weights (mass)rough values

Quantities,rough values

single parts,small batch series

typical part

Machine moulding Shell casting Shaw-process

all metals all metals

up to several tons, restricted by the sizeof the machinery

small batch series up tolarge-batch production

no restriction,available transportationequipment and meltingcapacity determine theupper limit

2,5% up 5% 1,5% up 3% 1% up 2% 0,3% up 0,8%

pump case piston rings ribbed cylinder head hip-joint implate

all metals all metals

up to 150 kg

medium batch series up to large-batch production

up to 1000 kg

single parts, smallbatch up to mediumbatch series

tolerance rangefor 500 mm nomi-nal size (*)

(*) : The specified tolerances are rough values for a nominal size of about ca. 500 mm; they depend on the grade of accuracy, the part size and the material. Material related tolerance specification see also DIN1680 and DIN 1683 up to DIN 1688. source: ZGV

Survey: Casting in consumable moulds with permanent patterns


Structure of the lecture CastingIntroduction: Variety of applicationsBasics of castingProduction sequence at casting Production of casting patternsProduction of consumable moulds and coresCasting processes




27


Work flow of the sand casting process

source: ZGV

bottom box

moulding plate withhalf of the pattern

top box

core mark

bottom box

inserted core

feeder feederdownsprue

cast part


Driving wheel for a belt drivematerial: GJL-300diameter: 2850 mm

Base of a vertical boring and turning millmaterial: GJL-200diameter: 5800 mmweight: 44 t

Examples for application - Sand casting (hand moulding)

source: konstruieren+giessen 2/2000

28


Example of application - Components of a ship‘s propolsionprocess: sand castingmaterial: CuAl9Ni7

CuAl10Fe5Ni5weight: 1 propeller blade ca. 1300 kg

hub ca. 3000 kg

blade

hub

source: Zollern


Casting in sand at a semi-automatic moulding facility


29


Pump case made of low alloy GJL-300single weights: 362 resp. 144 kg

Example of application: Pump case - sand casting



Truck wheel hub (light weight design)nodular cast iron GJS-400-15weight: 17.6 kg

Differential castingnodular cast iron

Crankshaftnodular cast ironGJS-600-3weight: 13.4 kg

source: Georg Fischer, Mettmann

Example of application: Power transmission - sand casting

30


Example of application: Aluminium sand casting

Suction inletAl - sand casting, G-AlSiCu3weight: 16.8 kg

Oil panAl - sand casting / G-AlSiMg(wa)weight: 4.5 kg

Clutch housingAl - sand casting / G-AlSi9Cu3weight: 44.6 kg

source: Georg Fischer, Friedrichshafen






31


dW/d1 = 1,5

1: 250° hot pattern board 2: pre-baked shell mould 3: tilting the excessive mould material

moulding material

4: curing the shell mould 5: lift-off fixture 6: joining press

450 °C

7: casting of the mould on a casting bed

Work flow of the shell casting process

source: ZGV


Example of application: Shell casting process

metal pattern board casting mould and cast parts

source: UG Metal, Dk

32



- Casting in consumable moulds with permanent pattern- Casting in consumable moulds with consumable patterns

- Survey of different processes- Investment casting- Full mould casting

- Casting in permanent moulds without patterns



Process Investment casting

Possiblematerials



small batch series up tolarge-batch production

typical part

Full mould casting

all metals

1 g up to several kg(in special cases up to 100 kg)

0,3% up to 0,7% 3% up to 5%

turbine wheels machine base

all metals

no restriction (availabletransportation equip-ment), specially suitable for heavy transports

single parts, small batchseries (at suitable partsseries production)


(*) : The specified tolerances are rough values for a nominal size of about ca. 500 mm; they depend on the grade of accuracy, the part size and the material. Material related tolerance specification see also DIN1680 and DIN 1683 up to DIN 1688. source: ZGV

Survey: Casting in consumable moulds with consumable patterns

33








Work flow of the investment casting process - part 1

production of a wax pattern

joining single waxpattern to „clusters“

each wax cluster is robotically dipped intoa ceramic slurry, drained, and then coated

with fused silica sand

injection dies withwax pattern

ceramic dippingbaths ensure a firm ceramic cover

source: ZGV, Feinguss Blank

34


Work flow of the investment casting process – part 2

dewaxing baking of the ceramicshell mould

pouring the liquidmaterial in the ceramic shell

removing theceramic shell

about 1400°C inthe furnace

filling the preheated shell mould with liquid metal at ~1200°C

separating thecastings is always

done manuallysource: ZGV, Feinguss Blank


source: Zollern

Removing the wax pattern from the injection moulding die

35


Design guideline - curved channels

Kern

splitting splitting

= direction, into which the core slides are removed

Curved channels are particularly cost-effective, when they can be producedwith core slides inside the workpiece.

In all other cases, water-soluble or ceramic cores have to be used.

source: Zollern


ingate

The number of ingates can be reduced through placing cut-outs⇒ reduction the grad of bulkiness the effort during casting

possible favourableingate ingate

saved ingate

Design guideline - reduction of ingates

36


Two-piece wax pattern for a pump case part

source: Zollern

Composite patternsjoining splitted patterns usingfitting-marks

undercut-contures possible

at symmetrical patterns which consist of two parts, only one injection moulding die is necessary


filter eyematerial: G - X5 Cr Ni Mo Nb 18/10

turbine wheelsmaterial: G - X5 Cr Ni Mo Nb 18/10

Wax injection moulding with cermaic cores Wax patterns and cast parts

source: Zollern

Examples for wax patterns and respective cast parts

37


Steering knuckle mademade of 1.7744 (tempered steel); 6,0 - 8,0 kg

Turbine wheels and nozzle rings made of Ni-base-alloys, weight: 1,3 - 3,0 kg

Load carrier and holder for landing flapmade of 1.7744, weight: 3,2 and 4,0 kg

Different structural partsfor aircraft turbine engine hydraulicsmade of pretici-pation-hardened, corrosion-resistant steel,weight: 0,4 - 2,3 kg

Examples for investment casting parts: Aerospace applicat.

source: Thyssen


Steel investment cast parts made of G-X6CrNi 18.9.Parts of a component insertion machine, which are exposed with accelrating power up to 3,5 g.

Examples for investment casting parts: High-tech components

source: Thyssen, konstruieren+giessen 25 (2000) Nr.4

Top holder:dimensions: 165 x 150 x 190 mmmaterial: 1.4308 (G-X6CrNi 18.9)weight: 1340g Portal S 50

dimensons: 600 x 305 x 95 mmmaterial: 1.4308

(G-X6CrNi 18.9)

weight: 6800g

38


Examples for investment casting parts: Engineering industry

Head peace of a pneumticnailing machinematerial: GS-15 CrNi6 (1.5919)dimensions: 80x80x128 mmweight: 800 g

Lever for a packingmachinematerial: GS-42 CrMo4

(1.7225)dimensions: 215x115x107 mmweight: 6,3 kg

Casing for a hydraulicsystemmaterial: GS-45 CrMo4

(1.0443)dimensions: 215x115x107 mmweight: 1,9 kg

source: ZGV


Spiral pump casing –food processing industrymaterial: G-X 5 CrNiMoNb 18 10 (1.4581)dimensions: 245 x 265 x 30 mmweight: ca. 7 kg

Valve chambermaterial: GS-38 (1.0416)weights of pieces: up to 30 kg

source: Thyssen

Examples for investment casting parts

39


Compressor impellermaterial: G-X 5 CrNiMo 16 5 (1.4405)weight: 16 kg

Casing, impeller and cap for a pump used in thfood processing industrymaterial: G-X 5 CrNiMoNb 18 10 (1.4581)diameter of casing: 220 mmweights of pieces: up to 4,5 kg

source: Thyssen

Examples for investment casting parts


Hip-joint implantsmaterial: G-TiAI6V4

Implants for hip and knee jointsmaterial: G-TiAI6V4

Examples for investment casting parts: Medical engineering

source: Tital

40








Work flow of full-mould casting

source: ZGV

consumablefoamed plastic pattern

pattern embeddedin a one-piecemoulding box

without core!

without burrs!

41


Pattern made of polystyrene foam for a base of a machine tool (casting company) dimensions: 4800 x 2300 x 1650 mmweight of cast part: 9,5 tmaterial: EN-GJL-300 (GG-30, Ferrocast)

Foamed plastic pattern for a base of a machine tool




- Casting in consumable moulds with permanent pattern- Casting in consumable moulds with consumable patterns- Casting in permanent moulds without patterns

- Survey of different processes- Diecasting- Permanent mould casting- Centrifugal casting- Continuous casting


42


Survey: Casting in permanent moulds without patternsProcess Diecasting

Possiblematerials



series productionservice life of dies:Zn: 500.000 castingsMg: 100.000 castingsAl: 80.000 castingsCu: 10.000 castings

typical part

Permanent mould casting Centrifugal casting Continuous c.

diecasting alloys onAl-, Mg-, Zn-, Cu-, Sn-or Pb-base (ferrousmaterials in development)

light alloys, specialcopper based alloy, high-purity zink, lamellar andnodular graphite cast ironup to 100 kg(in special cases alsohigher)

series productionservice life of dies:Al: 100.000 castings

Al-alloy.: up to 50 kgZn-alloy.: up to 20 kgMg-alloy.: up to 15 kgCu-alloy.: up to 5 kg(restricted by the size of the diecasting machine)

0,1% up to 0,4% 0,3% up to 0,6% 1% 0,8%

oil pan, gera case piston tubes profiled bars

lamellar and nodular graphite cast iron,cast steel, light alloys,copper based alloys

,lamellar and nodular graph.cast iron,Cu-alloys

up to 5000 kg

series produciton,service life of dies:5000 up to 100.000 pc.depents on part size,casting material andtype of the die

depends oncross section, up to severaltons

lengt of castbillet dependson machine


(*) : The specified tolerances are rough values for a nominal size of about ca. 500 mm; they depend on the grade of accuracy,the part size and the material. Material related tolerance specification see also DIN1680 and DIN 1683 up to DIN 1688.source: ZGV






43


Principle of a hot-chamber diecasting machine

closing cylindertoggle mechanism(interlock)

core plate(moveable)

Clampingframe diecasting

mould

cavity plate(fixed)

injection cylinder

press ram

filling chamber

melting crucible

extrusion die (nozzle)


Hydro-mechanical cold-chamber diecasting machine

source: ZGV

a: closing cylinderb: round nutc: head plated: toggle levere: ejector cylinder

f: toggle link carrierg: core plate (moveable)h: pillari: ejector diek: cover die

l: cavity plate (fixed)m: pressure chambern: injection shot cylinder

legend:

44


source: Schimpke, Schroop

Operation cycle at cold-chamber diecasting process

I. III.

II. IV.


Arrangement of core pullers at diecasting mould

source: Schimpke, Schroop

filling port

cover die

ejector die

distributer core

core puller 3core puller 2

core puller 1

45


Classification of the process: cold-chamber diecastingRange of VACURAL parts: high quality production of thin

walled Al- and Mg-parts of high strength

Examples of applicationthin walled parts of the car body

as alternative to metal forming technologies

Principle of VACURAL™-diecasting method

source: Müller-Weingarten

legend:1 holding furnace 5 stationary platen 9 runner2 suction pipe 6 stationary die half 10 solenoid valve3 injecton chamber 7 vacuum valve 11 vacuum pump 4 injection piston 8 moveable die half 12 vacuum tank


source: Härer-Werkzeugbau

Example of application - diecasting: Truck oil pan and die

46


gear casematerial: aluminium diecasting

AlSi9Cu3weight: 5.4 kg

Torque converter housing HP500, ZFmaterial: aluminium diecasting

AlSi9Cu3dimensions: 542 x 553 x 553 mmwall thickness: 3,5 - 25 mmweight: 41,0 kg

source: (1) Georg Fischer, Herzogenburg; (2) Honsel

Example of application - diecasting: Gear case and converter






47


Work flow at permanent mould casting

melting casting heat treatment machining quality control

Casting in permanent mould!

mould materíal: - hot forming tool steel- heat resisting special alloys

source: Gontermann-Peipers


Principle of a two-piece casting die with core

core puller runner gate

feeder

cast part1st mould half

2nd mould half

48


Principle of low-pressure permanent mould casting

compressed-airp ~ 1,5 bar

casting die

graphite melting pot

heating

transformer coil

cast pot

feed tube

cooling air


Examples of application - Permanent mould castingSchmelzen Gießen

Wärmebehandlung


millingcircular table

melting casting

heat treatment

49


Example of application - Aluminium permanent mould casting

Gear casealuminium permanent mould castingmaterial: G-AlSi10Mg(wa)weight: 17.0 kg

Slide part of a chassis / left and rightaluminium permanent mould castingmaterial: GK-AlSi7Mg(wa)weight: 2.1 kg / 2.1 kg

source: Georg Fischer, Mettmann


expenditure of work and material; transport effortand energy expenseper workpiece

risk to produce scrap

thin walls of cast partspossible

fine grain

automatable

permanent mould casting casting in sand

+ -

- +

+ -

+ -

+ -

Comparison of permanent mould casting and casting in sand

50







mould

metal sand lining

rotation axis

horizontal vertical

cooling

cooled not cooled

Examples:

a, c: metal mould with horizontalrotation axis, without cooling

b: metal mould with core andvertical rotation axis,without cooling

a)

b)

c)

source: Spur

Differentiating criteria at centrifugal casting

51


Production of pressure pipes with centrifugal casting

stationaryrotational cylinder sand lining

core for sleeve cam roller

gate channel

foundry ladle


Centrifugal- und gravitational force at centrifugal casting

source: Spur

Fres

FCG

FresG

FC

Fres

G FC

A

Fres = FC - G

Fres = FC - G

G

M

G

Fres

FC

FC

Fres

e

Division of forces within the meltat horizontal centrifugal casting

Position of liquid metal in the permanent mouldat different rotationl speeds of the centrifugal casting machine

v1 v2 > v1

v3 > v 2 v4 > v 3

52


Example of application: Materials at centrifugal cast part

examples for materials(acc. to Gontermann-Peipers):

lamellar graphite cast iron acc. to EN 1561 (prior DIN 1691)

nodular graphite cast iron acc. to EN 1563 (prior DIN 1693)

austenitic cast iron acc. to DIN 1694

alloyed cast iron qualities acc. tocustomers request

machinig of a circular cast cylinder sleeve



Examples of application: Centrifugal casting

source: GTR

source: IPO, Sophia

53







foundry case

gate pot

permanent mould

cooling water

water spraying

driving pulleyscutting-off deviceblock tilter

Principle of vertical continuous casting

54


gate pot

permanent mould

cooling water

driving pulleys

Principle of horizontal continuous casting


liquid metal



Introduction: Variety of applicationsBasics of castingProduction sequence at casting Production of casting patternsProduction of consumable moulds and coresCasting processesCase studies: simulation during design and production

- Starting point: FE-analysis and tool design- Simulations- Critical areas at the cast part- Results of optimization

Case study: Rapid-Prototyping used at production of casting patternsComparison of costsSummary

55


new aluminium wheel is designed

Production by using the low-pressure permanent mould casting process

Simulation should help to reduce casting defects up front

- optimization of casting design for improved quality

- optimization of mould tempering for improved quality

The residual stress in the as cast condition should be considered atthe FE-analysis

principle low-pressure permanent mould castingsource: Magma

Casting simulation and process optimization at Al-wheel


Product Planning Production

CAD, CAE, FE Analysis, Casting Simulation

source: Magma

Integrated CAE technologies support simultaneous engineering

Kic

k O

ff

Func

tiona

l D

esig

n

Det

aile

d D

esig

n

Tool

ing

Proc

ess

Des

ign

Prot

otyp

ing

Prod

uctio

n

Qua

lity

Con

trol

56


Casting design: 3D CAD construction of the new Al-wheel

source: Magma


FE-analysis of the cast part

150 MPa

0 MPa

Stress and distortion under test load (3.500N in 630mm distance of the mounting plate).

The maximum stress value is about 80MPa.

150 MPa

0 MPasource: Magma

57


Casting design - Tool geometry

top core

bottom coreand slide

source: Magma


Tool and cooling channelscooling channel

cooling channel

die sections

ingate

source: Magma

58







Temperatures during filling

source: Magma

59


Solidification sequence

source: Magma


Cooling measureswater, 30°C

casting sectionsair, 60°C

ingate

air, 30°C

All cooling channels with individual time control

source: Magma

60


Tool temperatures - closed die

source: Magma


Tool temperatures - before openingHigh tool temperatures mean low heat reduction from the casting

source: Magma

61


Tool temperatures - upper core opens

slides open

source: Magma


Tool temperatures - before closing the die

tool closes again

source: Magma

62


Tool temperatures - closed tool, before next cycle

source: Magma






63


Critical section for feedingDensity between 90% and 100%

pores

Solidification time between 10s and 80s

hot spots

source: Magma


Residual stress and total deformation 1 (3)The residual stress is in the order of magnitude of the stress caused by the test load

source: Magma

150 MPa

0 MPa

64


150 MPa

0 MPa

Residual stress and total deformation 2 (3)Residual stress plus load stress…

150 MPa

0 MPa

source: Magma


Residual stress and total deformation 3 (3).... results in the total stress under load, that can be in the range

of the yield strength.

150 MPa

0 MPa

source: Magma

65







Density between 90% and 100%

Solidification time between 10s and 80s

strongly reduced porosity

better feeding through the spoke

Output of optimization: Reduced porosity and better feeding

source: Magma

66


Summary of the simulation case study „Al-wheel“The integrated casting simulation / FE-analysis of the original wheel design provided thefollowing information:

– casting defects due to hot spots and insufficient feeding would occur– the addition of residual stress and test load would lead to maximum total stress values above the yield

strength

Optimization measures have been worked out– tapering to support feeding– thicker spokes to support feeding and to reduce the maximum stress values

The optimization measures were proofed by casting simulation and FE-analysis

source: Magma



Introduction: Variety of applicationsBasics of castingProduction sequence at casting Production of casting patternsProduction of consumable moulds and coresCasting processesCase studies: simulation during design and productionCase study: Rapid-Prototyping used at production of casting patterns

- Starting point and result of optimization Comparison of costsSummary

67


Design if possible right-angled !No big and abrupt change of cross section!Designing the cells in the same size !Avoid that ribs run together at one node!Minimum wall thickness at cast part: 20 mm!

length: 1400 mmwidth: 500 mmheight: 150 mm

transverseacceleration: 2 gdeformation: 4 µm

production: o.k.

length: 1400 mmwidth: 500 mmheight: 150 mm

transverseacceleration: 2 gdeformation: 4 µm

production: o.k.

Example of application: High speed supporting table (1)



Load orientated ribbing

deformation: -50 %mass: -15 %costs: -10 %

Load orientated ribbing

deformation: -50 %mass: -15 %costs: -10 %


Example of application: High speed supporting table (2)

length: 1400 mmwidth: 500 mmheight: 150 mmweight: 140 kg

transverseacceleration: 2 gdeformation: 2 µmEN-GJS-400-18

length: 1400 mmwidth: 500 mmheight: 150 mmweight: 140 kg

transverseacceleration: 2 gdeformation: 2 µmEN-GJS-400-18

68


conventional Rapid-Prototyping

drawing

tool

wax pattern

investment casting

cast part

ca. 6 weeks

ca. 6 weeks

Σ = 12 weeks

CAD-Data

Rapid-Prototypingpattern

investment casting

cast part

ca. 1 week

Σ = 4 weeks

ca. 3 weeks

Production time of Al-precision cast parts-conventional and RP

source: Tital


Quickcast - ModellGear Case VW / Wolfsburg

cast partmaterial:GF-AlSi7Mg0,6weight: 18 kg

Example of application: Pattern for a gear case

source: Tital

69




Basics of casting




Casting processes

Case studies: simulation during design and production


Comparison of costs

Summary


Comparison of manufacturing costs for a gear case

number of produced parts

200 100 300 1000

man

ufac

turin

g co

st in

dex

of d

iffer

ntm

anu-

fact

urin

gm

etho

ds, i

nclu

ding

all

extr

a ch

arge

s

0

100

200

300

400

%

casting in sand

investmentcasting conventional

cutting processes

cast part: pump casematerial: aluminium-alloy

diecasting

70


manufacturing

manufacturing costs 100 % 50,5 %

material titanium

costs for fixtures resp. tools 100 %

costs for material

costs for machining resp. assembling

mass 4500 g

100 %

100 %

titanium

4400 g

64,6 %

96,5 %

3,9 %

assembling of 9 milled parts investment casting

1- prior ⇒ 2 - today

1 2

Investment casting contra assembling: Aerospace application

source: Tital




Basics of casting




Casting processes

Case studies: simulation during design and production


Comparison of costs

Summary

71


Explain the change of the crystal lattice during cooling down the liquefied material at the example of pure iron!

Outline and explain the globulitical, fringe crystal and monocrystalline solidification at turbine blades!

Coarse grain contra fine grain!

Nominate and explain different casting properties (5)! What is meant with „shrinkage cavitation“ and how does that casting damage arise?

How are the moulding and casting processes defined?

Nominate and explain different methods of core production!

Into which main groups (3) are the casting processes classified?

Explain the principal work flow of the casting processes which belong to the three main groups!

Nominate and explain the essential parts of a casting simulation!

Explain the proceeding of the rapid-prototyping process for production of casting patterns!

Catalogue of questions to summarize the lecture „CASTING“


Structure of the exercise Casting

Introduction

Requirement oriented design of cast parts- Casting faults- Shape and casting oriented design- Load oriented design- Machining oriented design

Film: Presentation and definition of casting processes

Exercises- Requirement oriented design of cast parts- Selecting a casting process

Primary shaping - Casting - RWTH Aachen University nucleation at side walls ... Classification of...

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