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Flashcards in casting Deck (60):
1

cope

the top part of the mould

2

drag

the bottom part of the mould

3

pouring cup

the entrance for the moulten metal

4

sprue

channel used to deliver moulten metal

5

gating system

channel used to deliver material to mould cavity

6

riser

extra void

7

parting line

interface seperati g cope and drag

8

core

sand or metal shape used tpo produce internal feature of a casting

9

mould cavity

the space to be filled with moulten mmaterial

10

draft

tapers on the cast that permits casting to be withdrawn

11

sand casting

uses pattern of final casting pressed into sand to create a mould caVITY WITH A RISER AND A SPRUE

12

sand casting pro

low cost, almost all types of materials can be cast, no limit on max wieght, complex shapes,

13

sandcasting cons

HIGH POROSITY ROUGH SURFace finish , llow dimensional accuracy

14

invessstment casting

a type of disposable mould casting where wax pattern is made from a modified replica of product that is coated in ceramic powder the wax is then melted away and MM is filled in the shel is then broken off usually with vibration

15

investment casting pro

excellent surface finish ,high dimensional accuracy almost unlimited intricasey most metals can be used no parting line concerns

16

investment casting cons

costly patterns and moulds high labour time consuming

17

slush casting

moulertn metal is poured into a metal mould the when the desired thickness of the skin is obtained mould is inverted and remaining MM poured out then casting is removed

18

slush casting app,iscations

used to create thin walled objects that are often decorational oftenused in theatre for props

19

pressure castingg

MM forced upward by gas pressure of vaccuum and this pressure is maintained intil solidification see(https://vle.shef.ac.uk/bbcswebdav/pid-3159519-dt-content-rid-8843518_1/courses/MEC130.A.180071/Man%20Tech%20Lecture%203%20%28PJS%29%202017.pdf) page 7

20

pressure casting pro

avoids rapin oxidisaton promotes directioonal cooling ( top down)

21

pressure casting con

long cycle time

22

die casting hot chamber

injection syustem forces MM out of hot chamber through a gooseneck uinto the die cavity where mm rapidly solidifies dies are usually cooled with liquid to improve die life

23

hot chamber pro

no open tranfer of MM fast cycle time goood product strength , exellent dimensional accuracey and Surface finish,

24

hot chamber cons

expensive requires a high production rate cannot be used for mTERIALS WITH A VERY HIGH MP

25

die casting cold chamber

injection syustem forces MM through a gooseneck into the die cavity where mm rapidly solidifies dies are usually cooled with liquid to improve die life. the differenec is that the mm is transported from a seperate melting place

26

cold chamber pro

good dimensional presision
good surfavec finish

27

cold chamber cons

expensive dies
requires a high production rate
trabsport of MM required

28

centrefugal casting

MM poured into a rotating mould
inertial force distriobutes mm into the mold cavitys
metal helld against waall till cooling takes place

29

true centrefugal cadsting

inner surface remains cylindrical used to produce hollow objects like pipeds or gun barrels https://www.youtube.com/watch?v=ZxVA-htTunU

30

semi centrefugal casting

used to cast parts with rotaitonal symetry

31

centriguging

spins forcing mm into die on outside of centriguge

32

centrifuging pro

wide range of cylindrical parts
good dimensional accuracy

33

centrifuging con

shape limited to cylindrical stuff mostly
expensive spinning equiptment

34

single crystal caasting

czochraiski proccess in wich a seed of a single crystal of sillicon contacts the topp of molten sillicon as seed is raised atoms of the ms sooolidify in the seeds pattern

35

single crystal pro

very low thermal creepused for high tempreture stuff

36

single crystal con

slow and expensive

37

powder metalurgy

powdered metals are blwnded then compacted (hot compaction=isostatic) then sintered.

38

powder metalurgy pro

no waste material
only need semi skilled labour
requires little to no finishing

39

atomisation

liquid metall broken up by jets of inert gas or water. size of particle producd depends on jet flow characteristic and temp of mm

40

reduction

metal oxides reduced by gas like co or h2 to produce uniformly spongy porous powder

41

electrolytic deposition

uses aquius solution or fused salts to produce a very pure poweder

42

comminution

mechanical proccess involving crushingg milling or grinding

43

blending (for powder metalurgy

powders are mixed with lubricants or other metals and blended to create uniform sized particless with desirable mechaniceal propertys

44

cold isostatic pressing

metal powders placed in rubber mould and pressed hydrostaticlaly

45

hot isostatic pressing

inert gAS USED AS a pressurising medium to produce excellent density ND good metalurgic bonding so good mechanical properties

46

powder rolling

powders pressed between gap with rollers compacting into a continous strip

47

extrusion

powders are placed inn a metal die and extruded

48

injection mouldiing

very fine metal powder blended with polymer or wax then pressed into shape then put in oven to remove polymer binder complex shapes easily produced

49

sintering

compressed metal powder heated ib controlled temp below melting point to increse strength and density and electrical and termal conductivity however the compact does shrink

50

forging

a workpiecce is shaped by compressive forces

51

coining

a type of forging proccess where a slug is completely inclosed in the die used to increse strength and surface finish

52

infiltration

slug of lower mp placed against the sintered metal infiltrates pores with capillary action

53

plating

a coating proccess that impaets resistance to were and corrosion

54

economics of powder mettalurgty

eliminates need for many secondary finishng
initial die and equiptment cost is high
generally at least 10,000 production rate required

55

continous casting

https://www.youtube.com/watch?v=SgAhwgyBsyM

56

tundish

bith where molten metal in continous casting is poured reduce inclusion by maximising residence time

57

mould for coniuos casting

copper and water coold lubricated with a mould flux and is the primary source of heat extraction

58

mould powder / flux

provides uniform cooling protects ffrom oxidisation and absorbs inclusions

59

gross cracks

up to 400mm long assosiated with poor mould level control

60

sub surface cracks

prevelent in medium carbon steal thermal shrinkage results in a uneven shell