CASTING REPORT LAB.doc

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ACULTY O MECHANICAL ENGINEERING

BMM 3611

MANU ACTURING PROCESSES LABORATORY

Lab METAL CASTING PROCESSPrepared by,

Ir. Mohd Rashidi bin Maarof

Lab Location

FKM Manufacturing Process LAB

Lab Objectives

By the end of this semester, students should be able to:

Perform moulding and casting o erations for sand casting based on the re ared attern

Analy!e the "uality of moulds and casting roducts roduced by sand casting o eration

2

Gro!p Me"bers St!dent I# Section

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A$STRACT



In erforming manufacturing rocess laboratory on casting, the ur ose is to erformmolding and casting o eration for sand casting based on re ared attern. Beside that,is to analy!e the "uality of moulds and casting roducts, roduced by sand castingo erations. Based on a re ared attern, sand casting is erfectly right because of ithas ad5antages in roduction of com le6 sha e, arts ha5ing hollo7 sections orinternal ca5ities and also contain irregular cur5ed surfaces. /asting rocess in5ol5edthree basic ste s 7hich are mould ma8ing, melting and ouring of metals into themould ca5ity and lastly remo5al and finishing of casting after com lete solidification.

he result and analysis of data on com osition of moulding sand and core sand used,melting and ouring tem erature of the used metal, list of allo7ances that generally

ro5ided on a attern and also defects roduced in casting is recorded. In the end ofe6 eriment, someone should be able to generate an intricate design by the method ofsand casting throughout 7hole rocess. here are a fe7 defects such as on the surface

ro9ection causes by a crac8 in the sand mold, therefore each ste in that rocess 7as

crucial to the final design and out ut. Lastly, it is substantial for students to befamiliar 7ith the conce ts and rocedures for ro9ects that 7ill ha5e to be done in thefuture.



%&INTRO#'CTION

'and casting is used to ma8e large arts ty ically Iron, but also Bron!e, Brass,

Aluminium;. Molten metal is oured into a mold ca5ity formed out of sand natural or

synthetic;. he rocesses of sand casting are discussed in this section< include atterns,

s rues and runners, design considerations, and casting allo7ance. 'and casting, the most

7idely used casting rocess, utili!es e6 endable sand molds to form com le6 metal arts

that can be made of nearly any alloy. Because the sand mold must be destroyed in order

to remo5e the art, called the casting, sand casting ty ically has a lo7 roduction rate.

he sand casting rocess in5ol5es the use of a furnace, metal, attern, and sand mold.

he metal is melted in the furnace and then ladled and oured into the ca5ity of the sand

mold, 7hich is formed by the attern.Pouring of molten metal re"uired a good disci line both from gating system

design and risering system a lication. 'e5eral arameters are a lied such as ouring

time, gating element, gating ratios, and slag trag system, method of solidification

beha5iour, feeding distances and feeding aids.

he sand mold se arates along a arting line and the solidified casting can be

remo5ed. 'and casting is used to roduce a 7ide 5ariety of metal com onents 7ith

com le6 geometries. hese arts can 5ary greatly in si!e and 7eight, ranging from a

cou le ounces to se5eral tons. 'ome smaller sand cast arts include com onents as gears,

ulleys, cran8shafts, connecting rods, and ro ellers. Larger a lications include

housings for large e"ui ment and hea5y machine bases. 'and casting is also common in

roducing automobile com onents, such as engine bloc8s, engine manifolds, cylinder

heads, and transmission cases.



2&O$(ECTI)E

• o get e6 erience on metal casting through the rocess of sand casting.• o become accustomed 7ith the language and rocedure of metal casting in

general and sand casting in articular.• o de loy the 8no7ledge of metal casting into ma8ing useful roducts through

the rocess of sand casting.

*&PRO$LEMS STATEMENT

• o re are the sand moulds use the re ared attern and e6 erience the metal

ouring to com lete the casting rocess• /om osition ofmolding sand and core sand used• Melting and ouring tem erature of the used metal• Allo7ances that generally ro5ided on a attern• #efects roduced in casting

+&PROCE#'RES



IG'RE+&%- Proced!re #ia.ra"

(. he attern is laced in flas8 7ith enough room for gating. Parting dust is a liedonto the attern to 8ee it from stic8ing. Parting dust is a hydro hobic material, itre els moisture.

). Fine riddle is used to co5er 9ust the attern, then fill u the flas8 7ith sand, le5elflush; 7ith the to . here is no need to riddle all the sand, 9ust ma8e sure there is

no lum s. he riddle fluffs the sand u so it can be ac8ed ro erly, the same 7aya flour sifter 7or8s.

4. Paddle side of rammer is used to tuc8 edges first. he sand is added to about )inches abo5e flas8.#rag section is stro8e off 7ith rammer. he first half mould or co e is finished and continued 7ith rocess of creating the drag

0. 'te (to 0 is re eated again in addition of i e to assist the formation of s ruehole.

+. he i e is remo5ed after the sand mould is com act enough. he attern isremo5ed from both half of moulds and then it 7ere assembled together.

=. he metal is melt inside the furnace. As it is fully melt, the metal is ta8en out of the furnace and oured into the mould through the s rue hole

2. he metal is let about (* minutes for com lete solidification. he mould is sha8enout to remo5e the sand and e6tract the solid metal





+&RE)IE1 O LITERAT'RE

T e /actor to considered d!rin. se3ection o/ castin. process

Castin. Met od Advanta.es #isadvanta.es Reco""endedApp3ication

Sand Castin. Least 16 ensi5e insmall "uantities

less than (**;

Ferrous and non @

ferrous metals may be cast

Possible to cast5ery large arts.

#imensionalaccuracy inferior toother rocesses,re"uires larger tolerances

/astings usuallye6ceed calculated7eight

'urface finish of ferrous castingsusually e6ceeds ()+RM'

$se 7henstrength 7eight ratio

ermits

olerances, surface

finish and lo7machining cost doesnot 7arrant a moree6 ensi5e rocess

Per"anent andSe"i4per"anentMo3d Castin.

Less e6 ensi5e thanIn5estment or #ie/astings

#imensionalolerances closer

than 'and /astings

/astings are denseand ressure tight

nly non@ferrousmetals may be cast

by this rocess

Less com etiti5e7ith 'and /ast

rocess 7hen three

or more sand coresare re"uired

%igher tooling costthan 'and /ast

$se 7hen rocessrecommended for

arts sub9ected tohydrostatic ressure

Ideal for artsha5ing lo7 rofile,

no cores and"uantities in e6cessof 4**



P3aster Cast 'mooth As /astfinish )+ RM';

/loser dimensionaltolerance than 'and/ast

Intricate sha esand fine detailsincluding thinner

As /ast 7alls are ossible

Large arts costless to cast than byIn5estment rocess

More costly than'and or PermanentMold@/asting

Limited number of sources

Re"uires minimumof ( deg. draft

$se 7hen artsre"uire smooth As/ast surface finishand closer tolerancesthan ossible 7ith'and or PermanentMold Processes



Invest"ent Cast /lose dimensionaltolerance

/om le6 sha e,fine detail, intricatecore sections andthin 7alls are

ossible

Ferrous and non@ferrous metals may

be cast

As@/ast finish =0@ ()+ RM';

/osts are higher than 'and,Permanent Mold or Plaster rocess/astings

$se 7hen/om le6ity

recludes use of 'and or PermanentMold /astings

he rocess cost is 9ustified throughsa5ings inmachining or

bra!ing

?eight sa5ings 9ustifies increasedcost

#ie Castin. Cood dimensionaltolerances are

ossible

16cellent art@ artdimensionalconsistency

Parts re"uire aminimal ostmachining

1conomical only in5ery large "uantitiesdue to high tool cost

&ot recommendedfor hydrostatic

ressurea lications

For /astings 7here enetrant die; or radiogra hicins ection are notre"uired.

#ifficult toguarantee minimum

$se 7hen "uantityof arts 9ustifies thehigh tooling cost

Parts are notstructural and aresub9ected tohydrostatic ressure



mechanical ro erties

5&MATERIALS AN# E6'IPMENT

i7 "ateria3s

Type o/ base sand /or "o!3d

Na"e O/ Sand #escriptions

'ilica 'and

'ilica 'i ); sand is the sand found on a beach and is also the mostcommonly used sand. It is made by either crushing sandstone or ta8enfrom natural occurring locations, such as beaches and ri5er beds. hefusion oint of ure silica is (,2=* D/ 4,)** DF;, ho7e5er the sandsused ha5e a lo7er melting oint due to im urities. For high melting

oint casting, such as steels, a minimum of E> ure silica sand must be used< ho7e5er for lo7er melting oint metals, such as cast iron and

non@ferrous metals, a lo7er urity sand can be used bet7een E0 andE> ure;

'ilica sand is the most commonly used sand because of its greatabundance, and, thus, lo7 cost therein being its greatest ad5antage;.Its disad5antages are high thermal e6 ansion, 7hich can cause castingdefects 7ith high melting oint metals, and lo7 thermal conducti5ity,



7hich can lead to unsound casting. It also cannot be used 7ith certain basic metal because it 7ill chemically interact 7ith the metal formingsurface defect. Finally, it causes silicosis in foundry 7or8ers

li5ine 'and

li5ine is a mi6ture of orthosilicates of iron and magnesium from

silica, therefore it can be used 7ith basic metals, such as manganesesteels. ther ad5antages include a lo7 thermal e6 ansion, high thermalconducti5ity, and high fusion oint. Finally, it is safer to use than silica,therefore it is o ular in 1uro efrom the mineral dunite. Its mainad5antage is that it is free

/hromite'and

/hromite sand is a solid solution of s inels. Its ad5antages are a lo7 ercentage of silica, a 5ery high fusion oint (,>+* D/ 4,4=* DF;;, anda 5ery high thermal conducti5ity. Its disad5antage is its costliness,therefore its only used 7ith e6 ensi5e alloy steel casting and to ma8e

cores.

3ircon 'and 3ircon sand is a com ound of a ro6imately t7o@thirds !ircon o6ide3r) ; and one@third silica. It has the highest fusion oint of all the

base sands at ),=** D/ 0,2(* DF;, a 5ery lo7 thermal e6 ansion, and ahigh thermal conducti5ity. Because of these good ro erties it iscommonly used 7hen casting alloy steels and other e6 ensi5e alloys. Itis also used as a mold 7ash a coating a lied to the molding ca5ity; toim ro5e surface finish. %o7e5er, it is e6 ensi5e and not readilya5ailable.

/hamotte'and

/hamotte is made by calcining fire clay Al) 4@'i ); abo5e (,(** D/),*(* DF;. Its fusion oint is (,2+* D/ 4,(>* DF; and has lo7 thermal

e6 ansion. It is the second chea est sand, ho7e5er it is still t7ice ase6 ensi5e as silica. Its disad5antages are 5ery coarse grains, 7hichresult in a oor surface finish, and it is limited to dry sand molding.Mold 7ashes are used to o5ercome the surface finish roblem. hissand is usually used 7hen casting large steel 7or8 ieces



8ii7E0!ip"ent and "ac ine

Non4/erro!s "e3tin. /!rnace

Furnaces are refractory lined 5essels that contain the material to be melted and ro5idethe energy to melt it. Modern furnace ty es include electric arc furnaces 1AF;, induction

furnaces, cu olas, re5erberatory, and crucible furnaces. Furnace choice is de endent onthe alloy system "uantities roduced. For ferrous materials 1AFs, cu olas, and inductionfurnaces are commonly used. Re5erberatory and crucible furnaces are common for

roducing aluminium, bron!e, and brass castings.Furnace design is a com le6 rocess,and the design can be o timi!ed based on multi le factors. Furnaces in foundries can beany si!e, ranging from small ones used to melt recious metals to furnaces 7eighingse5eral tons, designed to melt hundreds of ounds of scra at one time. hey are designed



according to the ty e of metals that are to be melted. Furnaces must also be designed based on the fuel being used to roduce the desired tem erature. For lo7 tem eraturemelting oint alloys, such as !inc or tin, melting furnaces may reach around +**D /.1lectricity, ro ane, or natural gas are usually used to achie5e these tem eratures. For high melting oint alloys such as steel or nic8el based alloys, the furnace must bedesigned for tem eratures o5er (=**D /. he fuel used to reach these high tem eraturescan be electricity as em loyed in electric arc furnaces; or co8e.

he ma9orities of foundries s eciali!es in a articular metal and ha5e furnaces dedicatedto these metals. For e6am le, an iron foundry for cast iron; may use a cu ola, inductionfurnace, or 1AF, 7hile a steel foundry 7ill use an 1AF or induction furnace. Bron!e or

brass foundries use crucible furnaces or induction furnaces. Most aluminium foundriesuse either electric resistance or gas heated crucible furnaces or re5erberatory furnaces.

9and4 e3d 3ad3e

In a foundry a ladle is a container used to trans ort and our out molten metals. It needs

to be

• 'trong enough to contain a hea5y load of metal.• %eat@resistant• %eat@insulated as much as can be managed, to a5oid losing heat and o5erheating

its surroundings.



For foundries ma8ing small castings, a hand@held ladle some7hat resembling a 8itchenladle 7ith a long handle to 8ee the heat of the metal a7ay from the erson holding it.Better "uality ladles ha5e a ouring li to aid accurate ouring.

:&#ISC'SSIONS AN# RES'LT

Cenerally sand casting roses need high indi5idual s8ill and techni"ue to ma8e sure

the art that roduces are erfectly follo7 the s ecification needed or less defect roduce.

As the sand casting lab section is done 7e can see the roblem comes, there is many

causes that ma8e the roblem a ear and 7e 7ill discuss about defect and causes, aten

of the mold and consideration must be ta8en to design the mold and roduct so that sand

casting rocess can be done smoothly and less defect form.

First, after 7e filled the attern 7ith sand 7e ha5e to remo5e the attern out of the

mold during this time had ma8e mista8e by too8 it out too fast and carelessly as a result

art of the mold not being molded ro erly and if the 7orst case, the mold cannot be used

at all because the sand is not com act. After 7e roceed to ne6t ste 7hich is ouring the

molten metal into the attern and remo5e the attern after cooling rocess, the roduct

form is our finished roduct had rough, irregular, surfaces of casting at the bottom of the

art. his is robably the result from the erosion of the sand mold.

'econdly, from our obser5ation the edges of our casted art 7e notice that some

indentations in the art. hose indentation is hot tears. %ot tears, also 8no7n as hot



crac8ing, are failures in the casting that occur during the cooling roses. his ha ens

because the metal is 7ea8 7hen it is hot and the residual stresses in the material can

cause the casting to fail as it cools. he hot tears can a ear on the surface or through

crac8s that initiate during the cooling of casting.

he other oint is, non@flat surface on our roduct. his is defect is named

inclusion. Inclusions are any foreign materials resent in the cast metal. Inclusion can be

found in many form such as o6ides, slag, dirt, sand or nails. Inclusions commonly causes

by im urities 7ith the molten metal, sand and dirt from the mould not ro erly cleaned,

brea8 a7ay sand from mould, core or gating system, gas from the metal and foreign items

ic8ed on the mould ca5ity 7hile handling. Inclusions are reduced by using correct grade

of moulding sand and ro er s8imming to remo5e im urities.

#e/ect Ca!ses

Bubbles In9ection tem erature too high

&on@uniform cooling rate19ector mar8s /ooling time too short

19ection force too high%ot tearing &on@uniform cooling rate

Flash In9ection ressure too high/lam force too lo7

$nfilled sections Insufficient shot 5olume'lo7 in9ectionLo7 ouring tem erature

Tab3e %-#efect that may occur during the casting roses

here are general considerations that must be ta8e care by us in order to form the

best casting roduct during the laboratory session. here are include:@



he #esign f /ast Parts'electing he /asting ProcessLocating he Parting LineLocating And #esigning CatesRunner #esign

#esigning ther Mold Features1stablishing Cood PracticesFinishing, #raft And he 'ection /hanges.

(; he #esign f /ast Parts:

/orners , angle and section thic8ness, this must be a5oid as much as ossible because

they act as stress raisers and may cause crac8ing and tearing of the metal during

solidification. Fillet radii should be selected to reduce stress concentrations and toensure ro er li"uid metal flo7 during ouring. Fillet radii usually range from 4 to )+

mm.

); 'electing he /asting Process:

/asting rocess selection cannot be se arated from a discussions of economic. From

figure ( it sho7 some of the ad5antages and limitations of casting rocesses that ha5e

an im act on casting design.



i.!re %- 'ummary of casting rocesses.

4; Locating he Parting Line:

A art should be oriented in a mold so that the large ortion of the casting is relati5ely

lo7 and the height of casting is minimi!ed. Part orientation also determines the

distribution of orosity. A ro erly oriented art then can ha5e the arting line

s ecified. he arting line is the line or lane se arating the u er and lo7er hal5es of

molds.

0; Locating And #esigning Cates:

Cates are the connection bet7een the runners and the art to be cast the consideration

in designing gating systems such as gates should feed into thic8 section of casting, a

fillet should be used 7here a gate meets a casting@ this 7ill roduce less turbulence



than abru t 9unctions, cur5ed gates should be a5oided and the minimum gates length

should be 4 to + times the gates diameter.

+; Runner #esign:

he runner is a hori!ontal distribution channel that acce ts molten metal from the

s rue and deli5ers it to the gates. ne runner is used for sim le arts, but ) runner

system can be s ecified for more com licated casting. Runner are used to tra dross

and 8ee it from entering the gates and mold ca5ity.

=; #esigning other mold features.

he main gold in designing a s rue is to achie5e the re"uired metal flo7 rates 7hile

re5enting as iration or e6cessi5e dross formation. Flo7 rates are determined suchthat turbulence is a5oided but the mold is filled "uic8ly com ared to the solidification

time re"uired.

2; 1stablishing good ractices

It has been obser5ed 7idely that a gi5en mold design can roduce acce table art as

7ell as defecti5e ones and rarely 7ill roduce good or only defecti5e art. o chec8

for defecti5e casting, "uality control rocedures are necessary. 'tart 7ith high@"uality

molten metal is essential for roducing su erior casting. &e6t , the ouring of metal

should not be interru ted, since this can lead to dross entrainment and turbulence.

Lastly, the different cooling rates 7ithin the body of a casting cause residual stresses,

stress relie5ing thus may be necessary to a5oid distortions of casting in critical

a lication.



;& CONCL'SION

As a conclusion, 7e ha5e to follo7 the ste s of sand casting to ma8e sure that there are

lac8s of defects. For e6am le, 7e had hot tear on our ro9ect as a defect. ?e identified

that maybe there is non@ uniform cooling rate. hen, it 7as maybe because of the

im ro er attern design and metal com ositions. For unfilled section defect, the causes

are lo7 ouring tem erature and insufficient material.

?e should ha5e im ro5ement to ma8e sure that the design is lac8 or no defect. Firstly, the

sand should be se arate from the foreigner ob9ects, then, the sand should be com act

ro erly to ma8e the design is not getting crac8. &e6t, the moulding attern should be

ractice. ?e also ha5e to follo7 the ste s in sand casting ro erly.

In this e6 eriment or laboratory, 7e had learned some 8no7ledge beside 7e ha5e through

the e6 erience so that 7e can a lied 7hen in 9ob field.



<&RE ERENCES

(i) htt : en.7i8i edia.org 7i8i 'andGcasting

(ii) Manufacturing 1ngineering and echnology, Fifth 1dition in 'I $nits, by'ero eKal a89ian and 'te5en 'chmid, Pearson Prentice %all

(iii) htt : 777.thelibraryofmanufacturing.com metalcastingGsand.html

(iv) htt : 777.custom artnet.com 7u 'and/astingH ossibleGdefects

http://en.wikipedia.org/wiki/Sand_casting

http://www.thelibraryofmanufacturing.com/metalcasting_sand.html

http://www.custompartnet.com/wu/SandCasting#possible_defects

http://en.wikipedia.org/wiki/Sand_casting

http://www.thelibraryofmanufacturing.com/metalcasting_sand.html

http://www.custompartnet.com/wu/SandCasting#possible_defects

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