composites

Question 1

what is PMC

Answer 1

polymer matrix composites
a composite consisting of a polymer imbedded with reinforcing phase

Question 2

what are shaping processes for PMC

Answer 2

open/closed mold proocesses
filament winding
pultrusion

Question 3

What is a FRP

Answer 3

Fibre reinforced polymer

Question 4

what is a reinforcing aject

Answer 4

fibres
particles
flakes

Question 5

what are some of the forms of continuos filiment

Answer 5

Roving- untwisted strands
yarn-twisted filiments
cloth-woven yarns
woven roving- fabric constisted of untwisted filaments
Mat- felt consisted if short fibers held together
preforms- mats that are shaped for lclose molding processes

Question 6

what is open mold processes

Answer 6

procwsses that use a single positive or negitive mold to produce the sructures

Question 7

what are 3 examples of open mold processes

Answer 7

hand lay up
spray up
automated lay up

Question 8

what is the process for the hand lay up method

Answer 8

1. coat mold with release agent
2. a thin coat of resin is appliedto the outside of the mold
3. when the resin is set more layers of resin and fibers areapplied
4. part is cured
5. part is released

Question 9

whhat kind of products are suited for hand lay-up

Answer 9

large in size but low in quality

Question 10

what can hand lay up molds made from

Answer 10

plaster prototypes
FRP - for medium volume
Matel- high volume

Question 11

what are some applications for hand lay up

Answer 11

boat hulls
swimming pools
large container tanks
other formed sheets

Question 12

what is the spray up method

Answer 12

liquid resin is sprayed onto an open mold
spray gun moves fibers 1-3 inches long and add them to resin stream

Question 13

what are automated tape laying machines

Answer 13

a machine that dispenses prepeg tape onto a an open mold

Question 14

what are some applications made by spray up methods

Answer 14

boat hulls
bath tubs
shower stalls
automoative body parts
rv components
furnature
large structural pannels
containers

Question 15

what is prepeg

Answer 15

a composite material made for pre impregnated fibers and parially cured polymer matrix

Question 16

what are automated fiber placement machines

Answer 16

despenses prepegs in flat bundles of fibers impregnated with resin

Question 17

closed mold processes basics

Answer 17

preformed in molds with 2 sections
tool costs twice as much as open molding as more complex equipment is required

Question 18

what are the advantages of closed mold processes

Answer 18

good finish
high production rates
closer control on tolerances
more complex 3 diensional shapes

Question 19

what are 3 closed molding processes

Answer 19

compression
transfer
injection

Question 20

what is are the 2 differnet types of compression molding

Answer 20

preform
elastic reservoir

Question 21

what is preform molding

Answer 21

placemeny of a pre cut mat into lower mold secrion and resin goes into the fiber mat

Question 22

what is elastic reservoir molding

Answer 22

a sandwich of a foam core has liquid resin brought between the 2 dry fiber layers

Question 22

what is tranfer molding in composites

Answer 22

very similar to the plastic version in that fluid polymer is transfered fro pot to mold

Question 23

what process can mold thermosets with short fibres

Answer 23

transfer molding for composites

Question 24

what is a common variation of tranfer molding

Answer 24

resin transfer molding

Question 25

what are the materials in injection molding

Answer 25

thermoplastics thermosets

Question 26

what is the one thing that has to happen in the injection molding

Answer 26

the chopped fibers must be used

Question 27

what happens to to the fibers during the injection molding process

Answer 27

they become aligned which can create directional properties

Question 28

what is filament winding

Answer 28

continuios fibers are wrapped around a rotating mandrel

Question 29

what is pultrsuion

Answer 29

similar to extrusion but filament is pulled through a die

Question 30

what are the 5 steps of pultrsuion

Answer 30

1. filament feeding 2. dipping fibers in resin 3.pre die forming 4. shaping and curing 5. pulling and cutting

Question 31

what are some other PMC shaping composites

Answer 31

centrifugal casting tube rolling continuous laminating cutting of FRPs

Question 32

what are the 2 basic steps in good rubber production

Answer 32

production of rubber processing into finished products

Question 33

what are the steps in processing for rubber

Answer 33

compounding mixing shaping vulcanizing

Question 34

what is coumpounding

Answer 34

adds chemicals for vulcanizing

Question 35

why are dditives added in rubber

Answer 35

tgo enhance mechical properties to extend the rubber cost

Question 36

what is carbon black

Answer 36

the most important filler in rubber

Question 37

what is the effect of carbon black

Answer 37

increase tensile strength increase resistance to abrasion and tearing provides protection for ultraviolet radiation

Question 38

what is mixing

Answer 38

additives being mixed into the rubber

Question 39

what are the 2 stages of mixing

Answer 39

1) carbon black and non vulcanizing addives are added 2) vulcanizing agents are added

Question 40

what is vulcanization

Answer 40

a treatmet that accomplishes the crosslinking of the elastomer

Question 41

what is the purpose of filament reinforcement

Answer 41

reducue extenibility but retain other desirable properties

Question 42

what are bthe 4 basic catagories of shaping

Answer 42

extrusion calendering coatikng molding/casting

Question 43

what is some exapmes of rubber products

Answer 43

footwear seals shock absorbition parts converyor belts foamed rubber products sports equipment

Question 44

what sre the 2 types of hoses

Answer 44

plain hose reinforced tube