exma processes polymers

Question 1

injection moudlign step by steo

Answer 1

polymer granuels in hopper
fed into ehated barrel with screw
driven by motor
fed into controlled split
liquid injected into mould
water pumped aroudn to cool
mould opens and steel ejector pins force out

Question 2

injection moudl diragam left to right

Answer 2

motor
feed hopper
heaters
screw
female moudl
male mould

Question 3

where ejector pins in inj moulding

Answer 3

between male and female moulds

Question 4

what is male moudl pushed by

Answer 4

hydralich ram

Question 5

qc for inj mould

Answer 5

wall thcikness
ribs
avoid sharp corners
avoid blind holes
draft angle
removal of flash

Question 6

adv of inj mould

Answer 6

3d shapes
high volumes
very fast
low laboru cost
low waste
no finsihing really

Question 7

cosn of inj moudl

Answer 7

high inital set up costs
expensive moulds

Question 8

materials for inj moulding

Answer 8

pp
abs

Question 9

how extrusion work

Answer 9

same as inj mould
but just forced through die
into cross section
as psuhed out, itno water tank
on coveyor belt
to cool
then cut to size
cut to size

Question 10

materials in extrussion

Answer 10

polyetehelene
nylonn
upvc
pvc

Question 11

adv of extrusion

Answer 11

consitent profile
simpel dies needed

Question 12

cons of extrusion

Answer 12

have to cut to shape
only suitabel for cotnuosu flow productio

Question 13

blow moudling step by step

Answer 13

pre form (pariosn) injection moulded
parsion placed into the mould
air injected into the parisom

Question 14

blwo moudl diragam

Answer 14

parison in between mould
mould sealed
compressed air blwos into the shit
moudl opens
shit released

Question 15

what si the air that is blown in blwo moudling

Answer 15

hot

Question 16

does extrusion shit go straight to blwo moudlign

Answer 16

yes

Question 17

blwo moudling qc to rememeber

Answer 17

removal of flash
cooling system on outside

Question 18

is blow moudling liely to be fully auto

Answer 18

yes

Question 19

pros of blwo moudling

Answer 19

unfirom shaoe
fast
efficient
low or high scales
many palstics used
less expnesive than inj

Question 20

cons of blow

Answer 20

limited to holllow parts
moulds can be expensive
only curved shapes really

Question 21

cosnideratiosb for blwo moulding

Answer 21

accurate split mould
parison transfered to mould whilst still hot
thicker sections say for threaded parts

Question 22

all polymer moudls should accoutn for what

Answer 22

shrinkage

Question 23

rotational moudling step by step

Answer 23

graneuls placed in mould
mould clamped
moudl rotated in heated chamber
many spin
ensure even cotating
mould cooled
product removed

Question 24

how polymer granels heated in rotational moulding

Answer 24

by spinny bit being in heated champed or oven

Question 25

how polymer grnaels cooled for rotational moulding

Answer 25

air or wtaer channells and shit

Question 26

diagram for rotational moudling

Answer 26

mould has polymers in sealed clsoed spinny in heated chamber spin left to cool and set removed

Question 27

adv of rotational

Answer 27

hollw part made in one piece with no lines npo waste material diff products moudled togehter in oen machien surface textures low cost machienry and tooling

Question 28

con of rotational moudlign

Answer 28

only hollow shapes produced polymer needs to be precise amouts etc long cycle times

Question 29

polyemrs fo roational

Answer 29

polypropelene pvc PET

Question 30

how comp mould word

Answer 30

compressed palstci powder is set between two moudl haves mould heated and and pressure set untilshape tkaes ould cavity and solidifies

Question 31

what si top mould of comp moudl attatched to

Answer 31

hydralich ram

Question 32

what materials used in comp moudlign

Answer 32

thermo setting palstics

Question 33

once moudl caivty filled in comp moudl what happens

Answer 33

heaters turned off moudl allwoed to cool themroettign thing cures and hardness

Question 34

what is there at bottom of comp moudl, bottom mould

Answer 34

ejector pin

Question 35

pros of comp mould

Answer 35

ideal for themro palstics long rpodcution runs low set up and moudl cost little waste ideal for creating solid parts with thick walls no need for prew or runners

Question 36

cons of comp mould

Answer 36

cycle tiem long limtied size and compexity fo products

Question 37

what si trabsfer moulding

Answer 37

comp moudling but polymer shit in open pot at top plunger forces shit into the moudl via sprue

Question 38

thermo forming step by step

Answer 38

sheet palstic between two halves palstci heated jist above melting point moudls close togehter vaccum applied

Question 39

pros fo thermo forming

Answer 39

low cost works wellcreatign smooth shit that need soem extra detail

Question 40

which side of moudl wil detail be on

Answer 40

upper

Question 41

how vacc form work

Answer 41

quality former made former palced on bed or palten of machien platen lowered thermo polymer clamped into position heater heats polymer until soft platen rise and in contact with palstic heat removed vaccum on suck material cooled air or water moudl released bosh

Question 42

finishign on vacc formign

Answer 42

trimming cutting drilling polishing

Question 43

vaccum form diagram

Answer 43

heater ontop plastic beteen clamps platen with moudl ontop air on shti to dispaly

Question 44

pros of vacc formign

Answer 44

availabel in schools simple process moudls can be made inexpsnive sutiabel for raneg of scales

Question 45

cons of vacc formign

Answer 45

additional processing draft angles needed udercuts with certain moulds depth of mould webbing not intricate details

Question 46

when cna there by intriciate detail on vaccum formig

Answer 46

using a think sheet fo material l where surcae added to moudl on surfcae

Question 47

shit to be made w vacc formign

Answer 47

yoghurt pots disposable cups sandwich oacks multi parts in single former

Question 48

how doem blowign work

Answer 48

same as vacc form but shaped ring ontop of polyer air blwon up and polyer rises

Question 49

how blwon dome set

Answer 49

cool air blwon

Question 50

how calendaring work

Answer 50

melted thermpolymer fed into rolers rolers heated just aboev softwening point fo palstic plastic is pulled and forced through roller the final roller cools material then oen role winds up

Question 51

adv of calendarign

Answer 51

cotnuous rolls no joins good for long flat sheets can be combiend with pritnign and sht

Question 52

cons of calendarign

Answer 52

sutiabel only on large scale

Question 53

producst made in calendarign

Answer 53

floor coverings shower curtains signs and displays tabel covers

Question 54

how dip moudling work

Answer 54

moudl dipped into bath of moutlen liquid mould removed after layer coated moudl cooled end product removed

Question 55

adv of dip moulding

Answer 55

good for short run quick no split lines

Question 56

cons of dip moulding

Answer 56

limtied to simpel shape s

Question 57

products made from dip moudlign

Answer 57

ballons

Question 58

ssues w dip moudlign

Answer 58

can have drips and shit due to gravity when coolugn

Question 59

qc for polymers

Answer 59

removal of flash accruate measures draft angles cooling sytems