DEFNYDDIAU

MATERIALS

Ar gyfer unrhyw swyddogaeth peirianneg mae’n bwysig fod y defnydd yn addas ar gyfer y swydd.

For any engineering application it’s important that the material is suitable for the job.

METELAU / METALS

METELAU ANFFERUS /

NON FERROUS METALS

METELAU FFERUS /

FERROUS METALS

DUR /

STEEL

HAEARN /

IRON

DUR CARBON /

CARBON STEEL

DUR ALOI/

ALLOY STEEL

DUR CARBON UCHEL /

HIGH CARBON

STEEL

DUR CARBON

CANOLIG /

MEDIUM CARBON

STEEL

DUR CARBON

ISEL /

LOW CARBON

STEEL

SINC /

ZINC

COPR /

COPPER

ALIWMINIWM /

ALUMINIUM

ALOI ANFFERUS/

NONFERROUSALLOYS

DEIAGRAM DOSBARTHIAD METELAU

METALS CLASSIFICATION

DIAGRAM

METALAU FFERUS – cynnwys Haearn / FERROUS METALS – contain Iron

Er mwyn galw metel yn DUR rhaid i’r carbon fod o dan 1.8%, dros hyn mae’r metel yn galed iawn ond yn frau – esiampl Dur Bwrw Llwyd efo cynnwys carbon rhwng 3.2% a 3.5%. Mae’r diagram ar y dudalen nesaf yn dangos yr effaith mae carbon yn cael ar fetel.

To call a metal steel it must have less than 1.8% carbon, over this and it’s very hard but brittle,

example – grey cast irons has a carbon content of between 3.2% and 3.5 %. The diagram on the

following page shows the effect of carbon on metals.

ENW / NAME CARBON % DEFNYDD / APPLICATION

DUR MEDDAL MARW

DEAD MILD STEEL

DUR RHATAF AR UN A DDEFNYDDI’R FWYAF

CHEAPEST STEEL BUT MOST WIDELY USED

LOW CARBON ISEL

0.1 - 0.15

PANELI CEIR, WEIREN A TIWBIAU

CAR BODY PANELS WIRE + TUBE

DUR MEDDAL

MILD STEEL

LOW CARBON ISEL

0.15 - 0.3

GWAITH CYFFREDINOL GWEITHDY

GENERAL PURPOSE WORKSHOP

DUR MEDDAL CANOLIG

MEDIUM CARBON STEEL

CRYFACH, MWY GWYDN A CALETACH OND MWY COSTUS

NA DUR CARBON ISEL

HARDER, TOUGHER AND STRONGER BUT MORE COSTLY

THAN LOW CARBON STEEL

0.3 - 0.5

SIAFTIAU CRANC, GOFANNU, ECHELAU

CRANKSHAFTS, FORGINGS, AXLES

0.5 - 0.6 PENNAU MORTHWYL, CYNION OER

HAMMER HEADS COLD CHISELS

DUR CARBON UCHEL

HIGH CARBON STEEL

CRYFACH, MWY GWYDN A CALETACH OND MWY COSTUS

NA DUR CARBON CANOLIG

HARDER, TOUGHER AND STRONGER BUT MORE COSTLY THAN MEDIUM CARBON STEEL

0.8 – 1.0 SPRINGIAU COIL , CYNION COED

COIL SPRINGS, WOOD CHISELS

1.0 – 1.2 FFEILIAU, DRILIAU, TAPIAU / DEIAU

FILES, DRILLS, TAPS / DIES

1.2 – 1.4 ARFAU YMYLON MÂN – CYLLILL

FINE EDGED TOOLS - KNIVES

HAEARN BWRW LLWYD

GREY CAST IRON

DEFNYDD CALED IAWN – OND RHY FRAU AR GYFER ARFAU

VERY HARD MATERIAL – TOO BRITTLE FOR MAKING INTO

TOOLS

3.2 – 3.5 CASTIAU PEIRIANNAU

MACHINE CASTINGS

Tiwbiau / Tube

Weiren / Wire

Dalen + Plât / Sheet + Plate

Torch / Coil

Rhannau / Sections

Castinau / Castings

Gofaniadau / Forgings

Bariau / Bars

Ffurfiau Cyflenwi Metalau / Forms of Supplying Metals

DEFNYDDMaterial

DWYSEDD Density Cost/tonne Cost /m3

kg/m3 £/tonne £/m3

DUR Carbon Steel 7820 550 4301

DUR Alloy Steels 7820 830 6490,6

HAEARN BWRW Cast Iron 7225 830 5996,75

DUR GWTHSTAEN Stainless Steel 7780 4450 34 621

ALOI ALIWMINIWM Aluminium/alloys 2700 2220 5994

ALOI COPR Copper /Alloys 8900 5550 49 395

ALOI ZINC Zinc alloys 7100 2220 15 762

ALOI MAGNESIWM Magnesium /alloys 1800 4000 7200

ALOI Titanium /alloys 4500 17 000 76 500

ALOI NICEL Nickel alloys 8900 18 000

COSTAU METALAU METAL COSTSMetal costs depend on a number of factors:Purity of the grade, Alloying elements, Demand around the world, local economy,

Also the daily price of steel on the trading market

The table below gives a guide on the trading stock metal prices (2009)

Mae cost metel yn dibynnu ar nifer o bethau:Pa mor bur ydi’r gradd, Elfennau aloi, Faint sydd ei angen ar draws y byd, Economi lleol,

Hefyd pris dyddiol metel ar y farchnad stoc

Tabl isod yn rhoi syniad prisiau metel ar y farchnad stoc (2009)

BS970 Numbering system explained

The BS970 code number is constructed as follows;a) The first three symbols are a number code indicating the type of steel:000 to 199 Carbon and carbon-manganese steels. The number represents the manganese content x 100200 to 240 Free cutting steels. The second and third number indicate the sulphur content x 100250 Silicon Manganese valve steels300 to 499 Stainless and heat resisting steels500 to 999 Alloy Steelsb) The fourth symbol is a letter code .A The steel is supplied to a chemical compostion determine by analysis of the batch sample.H The steel is supplied to a hardenability specificationM The steel is supplied to a Mechanical Property specification.S The steel is a stainless steelc) The fifth and sixth symbol is a number is the actual mean carbon content x 100

BS 970-1:1996 Specification for wrought steels for mechanical and allied engineering purposes. General inspection and testing procedures and specific requirements for carbon, carbon manganese, alloy and stainless steels

METAL CODING SYSTEM

The purpose of the British standard 970 Coding system is to ensure every metal manufacturer uses the same codes for

“naming” all grades of steel –

An explanation of the standard and the coding system in given below – examples of popular meatals used are on the

following three slides

SYSTEM CÔD METALAU

Pwrpas ‘British Standard’ 970 ydi gwneud yn siwr for pawb sy’n cynhyrchu metel yn defnyddio yr un system er mwyn “enwi” graddau o fetelau gwahanol -

Mae esboniad o’r system rhifo isod – ac esiamplau o fetelau poblogaidd ar y dair sleid nesaf

Esiampl / Example

070M20Carbon Steel 0.7%

magnesium supplied as normalised with 0.2%

carbon

Or “Workshop Mild Steel”

Dur Carbon / Carbon Steel

BS 970 230M07(EN1A)

Dur carbon isel, sy’n torri yn rhwydd ac yn addas ar gyfer ei beiriannu. Ar gael mewn ffurf fflat, crwn a hecsagon .A low carbon, free cutting, mild steel suitable for machining using automatic and CNC machines. Available as rolled or normalised in round, flat or hexagon form

BS 970 070M20(EN3A)

Dur meddal ar gyfer defnydd cyffredinol – gellir ei weldio a’i beiriannu ac ar gael mewn amrywiaeth o siapiau.A mild steel used for general purposes. Suitable for lightly stressed fasteners ,shafts etc. Can be easily machined and welded. Available hot rolled, normalised, cold drawn or turned. Supplied in Black round or square , bright round square, flat and hexagon.

BS 970 080M30(EN5/EN6)

Dur a chryfder canolig – defnyddir i gynhyrchu siafftiau, bolltau, roleri ac yn y blaen (ar gael yn grwn. fflat neu sgwar).A medium strength steel. Used to make, shafts, racks, pinions, studs, bolts, nuts, rollers, etc. Supplied as square bar, or round bar or flat.

BS 970 080M40(EN8)

Dur a chryfder canolig – ar gael mewn ffurf sgwar, crwn a fflat.A medium strength steel. Suitable for stressed pins, shafts studs, keys etc. Available as rolled or normalised. Supplied as square bar, or round bar or flat.

BS 970 070M55(EN9)

Dur carbon canolig gellir ei galedu.A hard wearing medium carbon steel which can be hardened. Available as hot rolled, normalised, Cold drawn or turned. Sections available black round, black square, bright round and black flat.

BS 970 080M15(EN32)

Dur meddal ei gyfer ei grofennu ar gyfer pwrpasau cyffredinol o fewn peirianneg. Defnyddir i gynhyrchu geriau a roleri.A case hardening mild steel suitable for general engineering applications. When case hardened results in a hard surface with a tough core. Used for making gears cams and rollers etc. Supplied as black round bar and sections

CÔDAU DUR CARBON “POBLOGAIDD”

CODES FOR “POPULAR” CARBON STEELS

Dur Gwrthstaen / Stainless Steel

BS970 416S21(EN56)

Gellir ei galedu a’i dymheru er mwyn cryfder. Gellir ei ddefnyddio ar gyfer cytleri, offer llawfeddygol, falfiau a siafftiau.Martensitic (Magnetic), can be hardened and tempered to give improved tensile strength. FM** grade. Typical applications include cutlery, surgical instruments, fasteners, valves, spindles and shafts.

BS 970 431S29(EN57)

Defnyddir i gynhyrchu cytleri a falfiau ac yn y blaen.Martensitic (Magnetic). Supplied heat treated with a high tensile strength. Typical applications include cutlery, surgical instruments, fasteners, valves, spindles and shafts.

BS 970 430S15typ (EN60)

Gwan ond yn hydwyth – defnyddir ar gyfer offer arlwyo, egsost ceir ac yn y blaen.Ferritic. Low Strength but good ductility. Used food processing and catering equipment and automotive trim,car exhaust systems etc.

BS 970 Grade 304S15 (EN58-)

Aml bwrpas ac yn boblogaidd iawn ar gyfer ei ddefnyddio mewn sefyllfaoedd domestig.Austenitic (Non-Magnetic)Cannot be heat treated but work hardens. Readily formed and welded,used mainly in domestic, dairy and decorative appliances general purpose grade for corrosion resistant applications. This grade is the most widely used of all stainless steels. Its chemical composition,provide the best all-round performance S.S. at relatively low cost. It has excellent low temperature properties. Lower Carbon grades (S15 and less) have improved weldability.

BS 970 Grade 316S16 (EN58J)

Yn gwrthsefydd cyrydiad.Austenitic (Non-Magnetic)Cannot be heat treated but work hardens. It offers high resistance to corrosion. Generally machined components and pipe fittings. This grade is almost as popular as the 304 grade the increased Mo content makes the steel more suitable for resisting pitting and crevice then 304 Grade.  Lower Carbon grades (S15 and less) have improved weldability.

BS 970 Grade 321S12 (EN58B-C)

Ni ellir derbyn triniaeth gwres.Austenitic (Non-Magnetic)Cannot be heat treated but work hardens. Titanium stabilized, which offers improved welding properties.

BS 970 Grade 310S31Yn gweithio yn dda mewn tymheredd uchel.Austenitic (Non-Magnetic). Posesses good resistance to scaling at high temperatures. For continuous high temperature service in the range 850 - 1000C

CÔDAU DUR GWRTHSTAEN “POBLOGAIDD”

CODES FOR “POPULAR” STAINLESS STEELS

Dur Aloi / Alloy Steel

BS 970 605M36(EN16)

Hydwyth a gyda cryfder mecanyddol da.A manganese molydenum steel with good ductily and mechanical strength. Available in heat treated condition e.g (R,S,T).Supplied as black round or square bar and bright round or square, and hexagons.

BS 970 709M40(EN19)

Defnyddir ar gyfer sefyllfaoedd lle mae angen cryfder.A 1% typical chromium molybdenum steel with higher molybdenum. Can be induction hardened. Used for gears, and high strength shafts etc. Suitable for higher strength applications when resistance to shock is required. Available annealed. Supplied as black round or square bar and bright round or square, and hexagons.

BS 970 817M40(EN24)

Cryfder a gwydnwch yn amlwg.A nickel chromium molybdenum steel with high strength and toughness. Used for gears axles and high strength studs. Supplied as rolled, annealed and hardened and tempered. Supplied as black round or square bar and bright round or square, and hexagons

BS 970 655M13(EN36)

Ansawdd da lle mae angen arwyneb da.A high quality nickel chromium case hardening steel. Can be hardened to provide hard surface with a strong tough core. Used for high duty gears and shafts. Supplied in as-rolled condition in black square and round bar and bright round.

BS 970 722M24(EN40B)

Craidd gwydn gyda arwyneb da.A 3% chromium molybdenum nitriding steel. Provide good tough core strength with a hard nitrided surface for wear resistance. Supplied in as-rolled, annealed and hardened and tempered condition in black square and round bar.

CÔDAU DUR ALOI“POBLOGAIDD”

CODES FOR “POPULAR” ALLOY STEELS

Esiampl o system lliwio gan:Example colour coding from :

http://www.kelvinsteels.com/services.htm

CÔD LLIW METALAU

Pan yn prynu dur gan cyflenwr mae ganddynt system lliwio pennau pariay ayyb er mwyn adnabod y dur yn sydyn – ond nid oes system rhyngwladol felly mae pob cyflenwr yn defnyddio lliwiau gwahanol - rhaid archebu dur drwy ddefnyddio codau BS970!

METAL COLOUR CODING SYSTEM

Steel suppliers use a colour coding system to quickly identify a steel. The paint is

located at the ends of stock – however there is no international standard for colour coding

so each supplier use different colours- when ordering steel use the BS 970 coding

system!

ANFETELAU / NON -METALS

DEFNYDDIAU NATURIOL /

NATURAL MATERIALS

DEFNYDDIAUSYNTHETIG /

SYNTHETIC MATERIALS

ELASTOMERAU /

ELASTOMERS

THERMOPLASTIG

THERMOPLASTIC

MINERALAU /

MINERALS

DEIAGRAM DOSBARTHIAD ANFETELAU

NON - METALS CLASSIFICATION

DIAGRAM

THERMOSET

THERMOSET CERAMIG

CERAMICS

DEFNYDDIAU SMART

SMART MATERIALS

ELASTOMERAU /

ELASTOMERS PREN /

TIMBER

COPPER

Pure copper used for electrical components because of its high conductivity – second to

silver but a lot cheaper, however its too soft for mechanical work. Tough – pitch copper is used for mechanical tasks as its tougher due to the

inclusion of copper oxide. – properties– high strength, ductile, high electrical conductivity, resists corrosion, can

be soldered or brazed available in rods wire sheet and tubes.

ALUMINIUMPure aluminium is 33% the weight of steel,

but weaker and very difficult to join by soldering or welding, so it’s alloyed with other metals to

create stronger aluminium such as the components needed in aircraft.

Workshop aluminium contains up to 1% Silicon so its stronger and tougher easily joined and

machined.

BRASS

Alloy of copper and zinc, brass is attacked by salt water due to the zinc being attacked so Tin is added. Brass machines to a very high

finish – used a lot for plumbing and valve parts

METALAU ANFFERUS – dim Haearn / NON FERROUS METALS – no Iron

COPR

Defnyddi’r copr pur i wneud cydrannau trydannol oherwydd ei dargludedd uchel – ail i arian ond llawer rhatach. Mae rhy feddal I’w weithio yn fecanyddol ynbur, felly defnyddi’r Copt pich – gwydn, mae hwn yn cynnwys ocseid copr sy’n ei wneud yn fwy gwydn – priodweddion copr, cryfder uchel, hydwythedd uchel, atal cyrrydu, gallu ei sodro, ar gael fel rodiau, barrau, tiwbiau a llenfetel.

ALIWMINIWMMae aliwminiwm pur yn 33% yn ysgafnach na metel, ond llawer gwanach ac yn anodd i’w weithio drwy ymuno, felly rhaid adio metelau eraill i greu aloi sydd llawer mwy cryf a gwydn fel yr aliwminiwm sydd ei angen mewn cydrannau awyrennau.Mae’r aliwminiwm sydd yn y gweithdy yn cynnwys tua 1% o Silicon felly yn gryfach a mwy gwydn, hawdd i’w ymuno ai dorri.

PRES

Aloi o copr a sinc, gall pres ei ddinistrio gan ddwr halen oherwydd cynnwys y sinc, felly maent yn adio dipyn o Tin ir alloy. Mae press yn torri yn daclus arbeiriannau – defnyddio ar gyfer cydrannauplymio a partiau falfiau

NON - METALS

CERAMICS

Very hard material available in 4 groups CRYSTALLINE (hardest – used to

make cutting tools) AMORPHOUS, BONDED and CEMENTS. They are

very strong in compression, but brittle because they are very hard –

used as cutting tools and can cut HSS tools. They can withstand

high temperatures and are used as furnace liners, and are excellent

electrical insulators hence their use as insulators on high voltage cables.

WOODSGood fatigue strength because of its ability to bend .

Three classes of timber

Softwood – cheaper than hardwood, used for machine packaging, pallets, building frames,

example – pine.

Hardwood – More expensive than soft, used for decorative work, flooring or exposed building

framework, examples – oak, mahogany

Processed – fairly cheap compared to natural woods and less likely to distort – many types available with many applications, examples –

plywood, MDF.

ANFETELAU

SERAMIG

Defnydd caled iawn wedi ei rannu i 4 dosbarth CRYSTALLINE ( caletach – defnyddir fel arfau torri) AMRPHOUS, BONDED a CEMENTS. Cryf iawn dan llwyth cywasgiad, ond yn frau oherwydd yn galed – gall arf seramig dorri arf HSS. Gallant wrthsefyll tymheredd uchel a defnyddir i leinio ffwrneisi, ynyswyr trydannol gwych felly llawero ddefnydd fel ynyswyr as llinellau foltedd uchel.

COED Cryfder da pan o dan pwysau lluddeduTri dosbarth o coed:

Meddal – rhatach na caled – defnyddio ar gyfer pacedu, storio, fframwaith adeiladu, enghraifft - pinwydden,

Caled – Llawer drytach na meddal ai ddefnyddioar gyfer gwaith deiniadol fel lloriau neu fframiauadailadau gweladwy, esiamplau - derw, mahogani

Prosesu – defnydd rhad iw gymharu a pren Naturiol ac yn llai tebygol o colli siap – nifer fawrar gael gyda swyddogaeth eang, esiamplau – pren haenog, MDF,

Esiamplau / examplesalumina

silicon carbide zirconia

silicon nitride Diamond

Cubic boron nitride Magnesia

Tungsten Carbide

PLASTIG THERMOSET / THERMOSETTING PLASTIC

Plastigion ar gael mewn ffurf powdwr neu graniwl ac wed ei wneud o “llenwr” a resin synthetig. Cael eu mowldio fel arfer o dan bwysau a gwres. Unwaith mae wedi “ciwrio” gan y gwres ni all ei ail siapio

A plastic available in powder or granular form nade from a synthetic resin with a filler. Mostly moulded under pressure and heat. Once curing has occurred under heat it cannot be re heated and re shaped

Plastigion / Plastics

THERMOPLASTIG / THERMOPLASTIC

Plastigion gwahanol thermoset, posib ail siapio neu torri fynnu ai ailgylchu – Wedi gweld y symbolau yma or blaen?

The opposite to thermosetting plastic, possible to reheat and reshape, or cut up and recycle – Have you seen these symbols?

PhenolicsPhenolics are strong, brittle, good electrical insulators

and can withstand temperatures up to 150 deg. C.. Uses:-electrical plugs, switches, general electrical fittings.

Amino Plastic -UF..Urea FormaldehydeGood hardness, abrasion and chemical resistance. Safe

with food lots of colours.. Uses:- domestic plastics e.g toilet

seats, food containers.

Aminoplastic -MF..Melamine FormaldehydeHarder than UF . Good heat and stain resistance. Generally

used for domestic table ware. Glass reinforced laminates have

a heat resistance up to 200 deg. C.

Polyesters.Resistance to UV, water, acids, alkalis and organic

solvents. Usually reinforced with fibres mostly in the form of woven

clothchopped strands (GRP). Uses:- roof sheeting, car bodies,

tanks, boat hulls etc.

EpoxidesThey are tough and good resistance to alkalis. Uses:- encapsulate electronic components.

Glass-reinforced epoxides are used in chemical plants

PLASTIG THERMOSET / THERMOSETTING PLASTIC

PhenoligYn gryd, brau acyn insiwleiddwyr trdanol da. Gall

wrthsefyll tymheredd hyd at 150 C.Sar gyfer plygiau, swits ac offer trydanol cyffredinol.

Plastig Amino -UF..Urea FormaldehydeCaled, yn gwrthsefyll cemegau a sgriffiniadau. Yn ddiogel gyda bwyd. Defnydd: plastigau domestig,

seddau toiledau, blychau bwyd.

Plastig Amino-MF..Melamine FormaldehydeYn galetach na UF . Gwrthsefyll gwres a staen. Defyddir ar gyfer offer domestig. Gall laminadau gwydr wrthsefyll

gwres hyd at 200 C.

Polyestr.Yn gwrthsefyll UV, dwr, asid a thoddyddion.

Wedi eu cryfhau a ffibrau gwydr. Defnyddir ar gyfer cyrff ceir a chychod.

EpocsidauMaent yn wydn ac yn gwrthsefyll alcali. Defnyddir ar

gyfer cydrannau electroneg. Defnyddir epocsidau gwydr ar gyfer ffatroedd cemegolion.

THERMOPLASTIG / THERMOPLASTIC

ABS (AcronitrileButedeneStyreneTough, stiff, abrasive resistant. ABS can be injection

moulded, extruded, rotationally moulded and thermoformed. Typical applications include boat hulls,

telephones, piping/fittings, and domestic durables.

(Plasticised) PVC (PolyVinylChloride )Flexibility Used for cable/wire insulation, soles of

footwear, and coating linen liners of industrial gloves.

(UnPlasticised) UPVC (PolyVinylChloride )Hard/tough/ strong and stiff with good weathering

properties. UPVC can be extruded, injection moulded, blow moulded, rotationally moulded and

thermoformed. It is mostly used for making pipe/pipe fittings, bottles, and window frames .

PolyethyleneTough at low temperatures with excellent chemical

and electrical insulation properties. LDPE- Low Density Polyethylene is very tough and

flexible with excellent chemical resistance. Used for pipes

HDPE- High Density Polyethylene is much stronger and stiffer. It is used for tanks, pipes dustbins etc.

PolypropyleneExcellent fatigue resistances, chemical and electrical properties. Can be extruded, injection moulded, blow

moulded, rotationally moulded and thermoformed.

ABS (AcronitrileButedeneStyreneGwydn a gallu io wrthsefyll sgriffiniadau. Gellir ffurfio ABS

drwu fowldio chwitrell, allwthio, mowldio cylchol a ffurfio drwy wres. Defnyddir ar gyfer cychod, peipiau a llestri

domestig.

PVC (PolyVinylChloride )Hyblyg iawn. Defnyddir i gynhyrchu ceblau/insiwleiddio,

gwadnau esgidiau a menyg diwydiannol.

UPVC (PolyVinylChloride )Caled a gwydn gyda nodweddion gwrthsefyll tywydd da.

Gellir ei allwthio, chwistrell fowldio, mowldio cylchol a ffurfio gyda gwres. Defnyddir ar gyfer poteli, a fframiau ffenestri..

PolyethyleneYn wydn ar dymheredd isel gyda nodweddion cemegol a

thrydanol da ar gyfer insiwleiddio. LDPE- Polyethlen dwysedd isel – mae hwn yn wydn ac

yn hyblyg gyda nodweddion gwrthsefyll cemegol. Defnyddir ar gyfer peipiau.

HDPE- Polyethylen dwysedd uchel - yn gryfach ac yn anhyblyg. Defnyddir ar gyfer tanciau, peipiau a biniau

ysbwriel.

PolypropylenNodweddion da yn gwrthsefyl. Cemegau – gellir ei allwthio,

chwistrell fowldio, chwyth fowldio a ffurfio gyda gwres.

Acrylics Completely transparent and optically clear.

Stable to outdoor weathering and do not discolour or degrade under UV light. Acrylics are stiff, strong and do

not shatter.

Acrylics can be extruded, injection moulded, and thermoformed. Uses: - viewing panels, light housings,

lenses and illuminated signs.

Polycarbonates Tough, transparent, stiff and strong. Good electrical

insulation properties. Polycarbonates have moderate outdoor weather resistance.

Polycarbonates can be injection moulded, extruded, blow moulded, and vacuum formed.

USES: - include street lamp covers, safety helmets.

Polysulphones Strong and stiff. They do not easily burn and do not

present a smoke hazard. They can be extruded, injection moulded and thermoformed.

Uses:- passenger cabins in aircraft and electrical components requiring high service temperatures.

THERMOPLASTIGION AMORPHOUS /AMORPHOUS THERMOPLASTICS

Acrylig Yn dryloyw – yn addas ar gyfer dei ddefnyddio oddi allan, ddim yn colli lliw. Mae’n anhyglyg, cryf ac yn

gwrthsefyll dryllio.

Gellir ei allwthio, chwistrell fowldio a ffurfio gyda gwres. Defnyddir ar gyfer arwyddion, panelau a lensiau.

Polycarbonad Gwydn, tryloyw, anhyblyg a chryf. Gwrthsefyll trydan ac

yn gallu gwrthsefyll elfenau allanol.

Gellir ei allwthio, chwistrell fowldio, chwyth fowldio a ffurfio gwactod.

Defnydd: - helmedau a gorchuddion lampau stryd.

Polysulphones Cryf ac anhyblyg. Nid ydynt yn llosgi yn rhwydd ond yn gallu creu perygl gan gynhyrchu mwg. Gellir ei allwthio,

chwistrell fowldio a ffurfio gyda gwres.

Defnydd: cabin i’r teithwyr mewn awyren, cydrannau trydanol sydd angen gweithio mewn tymheredd uchel.

Nylon

Nylon materials are stiff, strong,tough and abrasion resistant. Nylon can be injection moulded, rotationally

moulded and extruded. Uses: insulators, and engineering components such as gears, bushes, and bearings. Glass filled nylon is used

to make power tool housings etc.

Polyacetals..

Stiff, strong, resist high temperatures .Uses: pipe fittings, light-duty beam springs, meat hooks,

gears, bearings etc.

PTFE..Polytetrafluoroethylene.

PTFE resists all common aggressive environments, has exceptional low coefficient of friction, first class electrical

properties and can be used at temperatures up to 250 deg C.

It can be processed only be a special sintering techniques. Complicated shapes are generally machined

from sintered blanks. PTFE is used for bearings, bearing surfaces treatments,

high frequency cable insulation, coating for cooking utensils etc etc

THERMOPLASTIGION CRYSTALLINE THERMOPLASTICS

Neilon

Mae deunyddiau neilon yn wydn, cryf ac yn gwrthsefyll sgraffiadau. Gellir ei chwistrell fowldio,

ffurfio cylchol a’i allwthio.Defnydd: insiwleiddwyr, a chydrannau peirianneg e.e geriau, beryn a bwshys. Gellir defnyddio neilon gyda

gwydr ar gyfer casyn offer trydanol.

Polyacetal..

Anhyblyg, cryf ac yn gallu gwrthsefyll tymheredd uchel.

Defnydd: ffitiadau ar gyfer peipiau, spring, geriau a berynau.

PTFE..Polytetrafluoroethylen.

Mae PTFE yn gwrthsefyll amgylcheddau ymosodgar, mae ganddo gyfernod isel o ffrithiant, priodweddau

da a ran ffrithiant a gellir ei ddefnyddio ar dymheredd o hyd at 250 gradd C.

Gellir ei brosesu gan ddefnyddio technegau sintro arbennig. Mae siapiau cynhleth i’w beiriannu a flociau

wedi eu sintro.Defnydd: beryn, insiwleiddio ar gyfer ceblau, wyneb

ar gyfer offer cegin.

RECOGNISING PLASTICSAn easy guide!

ADNABOD PLASTIGIONY ffordd hawdd!

A composite materials is created by combining two or more materials that have very different properties.  

The different materials work together to give the composite superior properties compared to the

individual properties of the original materials.  Within the composite the different materials are identifiable,

they do not dissolve or blend into each other.

The three main types of composite materials are:

1. Particle filled composite ....Particles have approximately the same dimensions in all directions

in a matrix. An example of this type of composite is concrete

2. Discontinuous fibre- reinforced...fibres have limited

length/diameter ratio in a matrix.   An example of this type of composite is Glass fibre

3. Continuous fibre-reinforced ... Continuous fibres are

constructed by winding or by using prepared layers. An example of this form of composite is the carbon fibre

COMPOSITES - REINFORCED PLASTICS

Gellir creu deunydd cyfansawdd gan uno dau neu fwy o ddeunyddiau gyda

priodweddau gwahanol. Mae’r deunyddiau yn gweithio gyda’u gilydd er mwyn creu deunydd gyda priodweddau

arbenig i’w gymharu a’r deunyddiau gwreiddiol. O fewn y deunydd cyfansawdd

gellir adnabod y deunydd gwreiddiol gan nad ydynt yn ymdoddi i’w gilydd.

Y prif fathau yw: 

1. Llenwad gronynau ....Gronynau gyda’r un mesuriadau mewn gwahanol

gyfeiriadau o fewn matirics. Esiampl yma yw concret.

2. Ffibr Gwydr...fmae ffibrau sydd wedi ei

gyfyngu mewn hyd a diamedr wedi ei gymysgu o fewn matrics.

3. Ffibr parhaol... Defnyddir ffibrau gan eu

gosod mewn haenau. Esiaml yma yw ffibr carbon.

DEFNYDDIAU SMART MATERIALS

Materials that have one or more properties that can be significantly changed in a controlled fashion by external stimuli, Some examples are as following:

Piezoelectric materials are materials that produce a voltage when stress is applied.

Shape memory alloys and shape memory polymers Change shape through temperature changes or stress changes

Magnetic shape memory alloys are materials that change their shape in response to a significant change in the magnetic field.

Temperature-responsive polymers are materials which undergo changes upon temperature.

Halochromic materials are commonly used materials that change their colour as a result of changing acidity. One suggested application is for paints that can change colour to indicate rust in the metal underneath them.

Electrochromic materials, which change their colour or opacity on the application of a voltage LCD’s

Thermochromic materials change in color depending on their temperature

Photochromic materials, which change colour in response to light—for example, light sensitive sunglasses that darken when exposed to bright sunlight.

Photomechanical materials change shape under exposure to light.

Self-healing materials have the intrinsic ability to repair damage due to normal usage, thus expanding the material's lifetime

Dielectric elastomers (DEs) are smart material systems which produce large strains (up to 300%) under the influence of an external electric field.

Gellir newid a rheoli deunyddiau sydd a priodweddau gwahanol gan ddigwyddiadau allanol. Dyma rai esiamplau:

Piezoelectric defnyddiau sy’n creu foltedd pan greir diriant

Aleoen cof neu polymerau cof yn gallu newid ffurf gyda gwres neu newidiadau diriant.

Ffurf cof magnetig mae’r aloeon yma yn newid eu ffurf gan ymateb i newid mewn maes magnetig

Polymerau sy’n ymateb i wres defnyddiau sy’n newid gyda gwres.

Halochromic – sef deunyddiau sy’n cael eu defnyddio lle mae angen newid lliw pan mae newid mewn asidrwydd. Un defnydd yma yw ei ddefnyddio i ddangos pa bryd mae metel yn rhydu.

Electrochromig sef deunyddiau sy’n newid eu lliw pan gyflwynir foltedd

Thermochromicg - sef deunyddiau sy’n newid lliw yn ddibynol ar eu tymheredd.

Photochromig – sef deunyddiau sy’n newid lliw gyda golau – e.e. sbectol haul sy’n tywyllu.

Deunyddiau Mecanyddol – yn newid ffurf gyda golau.

Deunyddiau adnewyddol – yn gallu trwsio eu hunain ac felly yn ehangu eu bywyd.

Elastomerau Dielectric (DE) - yn gallu ehangu o fewn maes electroneg (hyd at 300%)