Y7 Materials Project

This work can either be completed on paper, using computer software of

your choice, or both.

This investigation project should be completed over remaining 7 weeks

of term.

The project consists of 12 tasks investigation wood, metals and plastics.

Read all information and instructions carefully.

Material investigation

You need to know about different types of materials; woods, metals and plastics.

Specifically you need to know:

Specific examples of materials and their uses

Sources of materials (where they come from)

Treatments and finishes (what needs to be applied to the material before

being used)

Shaping techniques (how to cut and shape the material)

This project is broken down into 3 sections:

1. Wood

2. Metal

3. Plastics

Softwoods

Softwoods come from trees that grow in colder climates and grow faster making them

much cheaper.

Pine: Pine is yellow with brown streaks and lots of knots. It is strong but hard to work with,

its usually used for telephone polls and cheap furniture.

Larch: Larch has a yellowish reddish brown colour. Its harder than pine and resistant to rot

so it can be used for flooring and decking where pine wouldn’t last.

Spruce: Spruce is reddish brown and hard, it is quite knotty and not that durable. Its used

mostly for structural support in aircraft, crates and ship masts.

There are 3 different categories of wood:

Softwoods:- Pine, spruce, cedar

Hardwoods:- Oak, Mahogany

Manufactured boards:- Plywood, Chipboard, MDF

Natural wood is only available at the maximum width of the tree but manufactured boards can be produced in huge

sheets, if required. Some wood is made into moulding such as skirting boards or wooden trims.

Wood

Hardwoods

Hardwoods come from trees in warmer climates and grow slower and longer making them

have a tighter grain and be harder to produce and therefor much more expensive.

Oak: Oak is light brown with an attractive grain, it finishes well and lasts a long time so it

is often used for furniture but it does corrode steel screws.

Mahogany: Mahogany is very durable and dense but still easy to work with making it

perfect for luxury furniture, however it is quite expensive.

Beech: Beech is a pinkish-brown and quite hard, it can be bend using steam which makes it

good for chairs and toys.

Balsa: Balsa is an extremely light hardwood and is very soft. It is easy to cut out and file

making it perfect for modelling.

Ash: Ash is a pale creamy colour. It is very tough and a good shock absorber so it can be

used for tool handles and sports equipment. It also can be used for furniture.

Manufactured Boards

Manufactured Boards are made from other woods that are glued and compressed together

for a new purpose.

MDF: (Medium density fibreboard): MDF is made from small fibres of softwoods that are

held together by glue, that means it has no natural grain at all. Due to it being made of

cheap woods, it itself is very cheap to produce. It has a uniform surface that takes pain

well meaning it can be used for cheap flat pack furniture like the ones from IKEA.

Plywood: Plywood is a very commonly used material as it is very strong for its weight. This

is due to how its made, it is made from pieces of softwood or hardwood glued together at

right angles to one another giving it an alternating grain. It can be used for furniture and

building.

Chipboard: This is very similar to MDF but uses woodchip and sawdust over fibres. It is very

cheap but is without much strength, its also quite absorbent and can be damaged by

moisture. It can also be used for cheap self-assembly furniture.

1. What are the 2 categories of wood?

2. Where do softwood trees grow?

3. What is pine used for?

4. What is larch used for?

5. What does spruce used look like?

6. Where do hardwoods grow?

7. What does Oak look like?

8. What is Mahogany used for?

9. What does Beech look like?

10. What is balsa used for?

11. Why is ash used for tool handles?

12. How is MDF made?

13. What is MDF used for and why?

14. What makes plywood so strong?

15. State two disadvantages of chipboard

Task 1- Wood Softwoods

Hardwoods

Manufactured boards

All wood comes from trees. The process can be broken down into the following stages:

1. Trees are cut down from inside a forest or plantation

2. Their bark is then removed using saws (debarking).

3. It is then sawn up either in slab sawn (parallel cuts all the way through) or quarter

sawn into thinner planks.

4. The wood is seasoned by drying it either using air-drying or kiln-drying. Seasoned wood

is harder and rots less and can be used for lots of useful forms.

1. Air drying – traditional, cheap method where wood is stacked under a shelter to

protect from rain. Air circulates between the planks to slowly remove the excess

moisture. Air seasoned wood is used for outdoor wooden products because it is

seasoned to the same moisture content and its surroundings and therefore the

wood will be less prone to defects.

2. Kiln drying - more expensive but controlled method which is very quick and can

take just a few weeks. Indoor products such as furniture will use kiln-seasoned

wood because it has been seasoned to meet the indoor conditions and will have

low moisture content than air-dried wood

Wood- Conversion from raw materials

Slab sawn Quarter

sawn

Air drying

Kiln drying

1. Where does wood come from?

2. What is debarking?

3. Explain the two different ways timber can be cut

4. Why is wood seasoned?

5. Explain the process of air drying in detail- include images / sketches to help

6. Explain the process of kiln drying in detail- include images / sketches to help

Task 2- Conversion of wood from raw materials

Slab sawn Quarter

sawn

Air dryingKiln drying

The purpose of finishing / treating wood is:

Prevent the wood from absorbing moisture

Protect against decay

Protect against insect attack

Enhance the appearance of the final product

Natural wood can degrade in the following ways:

Altering wetness and dryness means that moisture is absorbed into the

wood. Although the surface may dry out, moisture remains below the

surface. This wet rot leads to breaking down of the wood fibres and a

fungus can spread throughout the wood. This converts wood into a soft,

crumbly state.

Insects can also lay eggs in the cracks in the wood and the hatched

larvae eat into the wood creating tunnels.

Before applying a finish, good surface prep is essential. They should be

planed or sanded with glass paper. Sanding should be done in direction of

the grain to avoid scratching the surface. When using glass paper, start with

the roughest (most coarse) progressing to finer grades.

You need to know about 4 different finishes for wood.

Wood- Treatments and finishes

Water-based paints

Available in gloss, satin, matt and

metallic effects. Applied with brush,

roller or spray. Treat knots with

knotting before applying paint to

prevent resin oozing out and

spoiling the finish. It can then be

primed and then an undercoat

applied prior to paint finish.

Provides protection and colour.

Indoor and outdoor use.

Stains

Available in many different

colours and types such as

mahogany and walnut. Apply

with brush, roller or spray.

Surfaces should be grease-

free prior to application.

Water or spirit based. Used to

colour inexpensive wood to

make it look like more

expensive timber. No specific

protective qualities.

Pressure treating

Wood is placed in a pressure vessel containing solution

consisting of copper sulphate and other preserving

salts or preservatives. Vacuum and pressure are

controlled to force perseveration deep into fibres of

the wood and then the wood is steam dried. Protects

wood for 50 years from rot, insects, fungal attack and

weathering. Used for decking and cladding.

Danish oil

Available in clear and

coloured tints. Rub the oil

into the wood with a cloth in

direction of grain. Not a very

hardwearing finish but

regular application and

additional coats build up a

matt, water-resistant finish.

1. State 4 reasons why wood are treated / protected

2. What is wet rot and how does it damage wood?

3. How do insect damage wood?

4. How is wood prepared before applying the finish?

5. How should sanding be carried out and why is this?

6. How is Danish oil applied?

7. Does Danish oil provide a water resistant finish?

8. How are water-based paints applied?

9. Why do knots need to be treating with ‘knotting’ before painting the wood?

10. What is pressure treating?

11. How long does pressure treating protect wood for?

12. How are stains applied?

13. Why are stains used to finish timber?

14. Do stains protect wood?

Task 3- Treatments and finishes of wood

There are different ways to shape and form wood. You need to know about 5

different ways that wood can be shaped:

1. Turning. This involves machining wood on a lathe. The wood is rotated

and tools applied to remove material. It is used to produce cylindrical

product such a table and chair legs.

2. Routing. Routers can be used to machine timber to make slots and

holes. They can be controlled by a computer or used manually.

3. Milling. Similar to routing, but milling machines run at a slower speed

for machining timber accurately. Also useful for small size, basic jobs

such as rough prototypes. Can be operated manually or by a computer.

4. Lamination. This is the process of bonding materials together. Veneers

(thin slices of natural timber) or thin manufactured boards can be

glued together and bent over a former / shape.

5. Steam bending. Heat and steam enables strips of timber to be made

really flexible so that they can be shaped over a former / shape.

Quicker than laminating- no glue drying time, also less wasteful as

laminating usually requires trimming to final size.

Wood- Shaping techniques

1. What is turning?

2. What types of products does turning make?

3. What is routing?

4. What is the difference between routing and milling?

5. What is milling used for?

6. What is lamination?

7. What are veneers?

8. What is steam bending?

9. Why is steam bending a quicker process than laminating?

Task 4- Shaping wood

Metal

Ferrous Metals are mostly made of iron, making most of them magnetic. They also rust easily so can

need coating to protect them. Iron is generally soft and ductile which does not make it a useful

material, so it is mixed with carbon. When carbon is mixed with iron, it greatly improves it’s

properties:

• Becomes harder

• Toughness reduces

• Can be heat treated to make them even stronger and harder.

Cast iron: Cast iron is very strong but brittle and not malleable. It is used mostly for car brakes,

manhole covers, cooking equipment and bench vices.

Low carbon steel: It is strong and cheap but rusts and cant be hardened. It is used in car bodies, nuts

and bolts, nails, screws

High carbon steel: This is harder than low carbon and can be hardened but isn’t easy to work with

and it can rust. This makes it good for tools like chisels, files, drills and saws.

There are 3 different categories of metal

Ferrous: Cast iron, low carbon steel

Non-ferrous: aluminium, copper

Alloys: solder, stainless steel

Ferrous metals

Non-Ferrous MetalsNon-Ferrous Metals don’t contain iron so they don’t rust making them good for being

exposed to moisture.

Aluminium: It is expensive, very lightweight but still fairly strong making it perfect for

aircraft but also for things like cans.

Brass: Brass is pretty strong, malleable, ductile and has a good colour meaning it is good

for decorative things like door handles and taps.

Copper: Copper is relatively soft, malleable and ductile. It is also very good electrical

conductor meaning it is perfect for electrical components and pipes.

Tin: Soft, low melting point and malleable. Good for tin cans and alloying metal in solder

Zinc: Its not very strong so is instead used with other metals to be useful, like coating steel

for nails and bolts.

AlloysAlloys are a mixture of 2 or more metals or with a different elements. They are new

materials; they have new properties to the metals they are made of. They or made to have

a specific property in mind when they are made.

Solder: solder is very fusible so it can be used to join up component parts

High speed steel: Contains Iron, >0.6% carbon, chromium, vanadium and tungsten. It is

hard even at high temperatures, so its used in high speed cutting tools that get very hot.

Stainless steel: Other steels and cast iron rust easily but adding chromium and nickel

increases the strength, toughness, ductility and reduces rust. It is used in cutlery and

surgical equipment.

1. What are the 3 different categories of metal?

2. What are ferrous metals mostly made of?

3. Why do ferrous metals need protecting?

4. What is iron mixed with to improve it?

5. State 3 advantages of mixing iron with carbon

6. State one property and one use for cast iron

7. State one property and one use for low carbon steel

8. State one property and one use for high carbon steel

9. What are ferrous metals?

10. State one property and use of the following non-ferrous metals

1. Aluminium

2. Brass

3. Copper

4. Tin

5. Zinc

Task 5- Metals High carbon steel saw blade

Cast iron

engine

block

Aluminium

kitchenware

Forged duralumin

bike gear

1. What are alloys?

2. What is solder used for?

3. What is high speed steel used for?

4. Chromium and nickel can be added to steel- why is this?

Metals are made from ores mined from the ground. An ore is a piece of rock with enough metal in it

for it to be profitable. The metal in the ores can be extracted in two ways: either through a furnace

or through electrolysis (using chemicals and running electricity through it).

Some metals are combined with materials to separate them out to be tapped off. These metals will

often have impurities which need to be removed for production uses, this process is called refining.

Metals will have different properties so refining each of them are unique methods.

Metal Extraction method Refining

Iron Furnace Limestone is added to remove sand

during extraction

Aluminium Electrolysis While the metal is molten, gases can be

pumped through and rise impurities to

the surface.

Zinc Furnace or electrolysis It has a lower boiling point so it is easily

heated and cooled to remove

impurities.

Copper Furnace Electrolysis will remove copper from

anything left in it.

Tin Furnace Impurities in tin react to heat to form a

substance to be removed. Or it can use

a similar method to Zinc. Or it can use

electrolysis.

Conversion of metal from raw materials

Task 6- Conversion of metal from raw materials

1. Where does metal come from?

2. What is an ore?

3. What 2 ways can metal be

extracted from the ore?

4. What is refining?

5. Why do some metals need

refining?

6. Explain how the following metals

are refined:

1. Iron

2. Aluminium

3. Zinc

4. Copper

5. Tin

Metals- Treatments and finishes

Tempering is a process that results in a blend of hardness,

strength and toughness through the entire section of the steel

(all the way through). It is a more ‘intense’ process than case

hardening.

First, the steel is heated to red hot and then plunged into

water. This hardens the steel, but it also makes it really brittle.

The steel is then heated until it is blue and then is allowed to

cool slowly. This reduces the brittleness but keeps the hardness.

Case hardening is a method of hardening the surface of steel.

This technique is used for steels with a low carbon content.

The steel is heated and then carbon is added to the outer

surface of the steel. It is heated again and then plunged into

cold water. This creates a hard outer shell but the inner core is

left untouched so remains flexible and relatively soft.

Annealing is a heat process where the metal is heated to a

specific temperature and then allowed to cool slowly. This

softens the metal, which means it can be cut and shaped

more easily.

You need to know about 3 different ways that metal can be treated / improved. All of them involves heating them.

Metals- Treatments and finishesMetal can also be ‘dip coated’. Dip coating gives the metal a ‘coat’ or outer layer of another material.

This material can either be plastic, or another metal.

Plastic

Used on wire coat hangers, kitchen dish drainers, dishwasher racks and outdoor play equipment

frames.

Metal heated to 230oC and then dipped into a tank of fine polymer powder which has air blowing

through it- to aid an even coat.

The heat in the metal melts the plastic and then air-cooled.

Metal

Metal can be coated with other metals by dipping into a tank of molten plating metal.

Often used for cheap metals such as low carbon steel to provide a barrier against rusting.

Must be cleaned and degreased before application.

Tin plating: sheets of steel passed through a tank of molten tin at 320oC. Use to provide non-

corrosive coating to food cans.

Zinc plating (galvanising): Dipping steel into molten zinc at 460oC. used for beams, gates and first

protective layer in car bodies made from low carbon steel.

Task 7- Treatment and finishes of metal1. What is case hardening?

2. What type of metal is it used for?

3. Briefly explain the process of case hardening

4. What is tempering and how does it improve the metal

(what is the result on the metal after tempering?)

5. What is annealing and what is the result on the metal?

6. What is dip coating?

7. Name some products that have been dipped in plastic

8. Briefly explain the process of dip coating metal in

plastic

9. What metal can be dip coated in another metal?

10. What is tin plating? Name a product that has been tin-

plated

11. What is zinc plating (galvanising)? Name a product

that has been galvanised.

There are different ways to shape and metal. You need to know about 2 different ways

that metal can be shaped; press formed or cast.

Press forming- carried out using a punch and a die which are both made form toughened

steel. This makes them resistant to impact loads so they last a long time. Car body

panels are pressed from mild steel sheet to produce the vehicle’s overall shape.

Pressing also increases the stiffness of the metal which is good for most products such as

car doors. Material can also be cut out during pressing- for example, the window of a car

door can be cut out when being pressed. So it can be shaped and cut out at the same

time. This saves money in the manufacturing process of cars.

Punch, die and formed metal

Car door being press formed

Metals- Shaping techniques

Casting- When molten, the liquid metal can be poured (or forced under pressure) into a mould.

Moulds can be created from sand, alloy steel or ceramics, depending on the metals being cast. There

are two different ways to cast metal; Sand casting and Die casting, but you only need to know about

sand casting.

Sand casting- Sand is used for the mould. Sand contains oils that help it hold its shape while the hot

metal is being cast into it. Complex 3D shapes can be produced, but usually only used for a small

number of items (i.e. not mass produced). The surface finish can also be quite rough- especially if

some of the sand doesn’t form properly- think of it like building a perfect sand castle- the smallest

imperfection of the sand mould will have an impact on the surface finish of the metal. See the next

slide for more detail on the process.

Sand cast car

engine block

Task 8- Shaping metal1. What are the two main ways metal can be

shaped?

2. In press forming, why is the die and punch made

from toughened steel?

3. Name a product that is made using press

forming

4. Press forming also makes the steel more stiff.

Why is this a good thing?

5. Press forming can also cut metal out, as well as

bending it. Why is this a good thing?

6. What is casting?

7. What are the two different types of casting?

8. In sand casting, why is sand used for the mould?

9. What types of product can be made from sand

casting?

10. The finish of the metal from sand casting can be

quite rough- why is this?

Properties of plastics

They are good electrical and thermal insulators

They have a good strength to weight ratio. This does not mean they are

strong materials in the same way that steel is strong, but that they have good

strength compared to their weight.

Generally, they have good atmospheric and chemical corrosion resistance.

Plastics can be grouped into types:

Thermoplastics – these materials can be repeatedly

reheated and remoulded.

Thermosets - (thermosetting plastics) – these undergo a

chemical change resulting in them becoming permanently

rigid, i.e. they cannot be reheated and reshaped

Plastics

Common thermoplasticsThermo-

plastic

Working name Characteristic Common

PET Polyethylene

Terephthalate

Moderate chemical resistance. Often

used for single-use products (but not

all the time)

Fibres used to make a wide variety of clothing,

bowl-moulded bottles for beers and soft drinks,

audio and video tapes, insulation tapes

HDPE High Density

Polyethylene

High density, good stiffness, good

chemical resistance

Crates, bottles, buckets and bowls

uPVC Polyvinyl

Chloride

Good chemical resistance, good

resistance to weathering, rigid, hard,

tough, lightweight, can be coloured.

Contains dangerous toxins.

Pipes, guttering, bottles and window frames

LDPE Low Density

Polyethylene

Low density (light weight), low

stiffness and rigidity, good chemical

resistance

Detergent bottles, toys and carrier bags

PMMA Acrylic Food-safe, tough, hard, durable,

easily machined

Light units, illuminated signs, lenses for car

lights

HIPS High Impact

Polystyrene

Good impact resistance, good

strength and stiffness, lightweight

Toys and refrigerator linings

Thermoforming Plastics don’t resist heat well and can be easily bent, melted and moulded

into shapes.

Thermoplastics

Thermoset plastics

Thermo-plastic Characteristic Common

Epoxy resins High strength when reinforced with

fibres (Glass reinforced plastic),

good chemical resistance and wear

Surface coating, encapsulation of

electronic components, adhesives

Melamine

formaldehyde

Rigid, good strength and hardness,

scratch-resistant, can be coloured

Tableware, decorative laminates

for work surfaces

Urea

formaldehyde

Rigid, hard, good strength, brittle,

heat-resistant, good electrical

insulator

Electrical fittings, adhesives

Epoxy Resins Melamine formaldehyde Urea formaldehyde

Thermosetting Plastics resist heat and are good insulators. They undergo a chemical change

once moulded so they permanently become hard. Making them non recyclable.

Task 9- Plastics1. What are the 2 different types of plastics?

2. State 2 properties of plastics

3. Plastics have a good to strength to weight ratio- what does this mean?

4. What is a common use of PET?

5. Why is HDPE used for bowls?

6. Why is uPVC used for guttering and window frames?

7. Why is LDPE used for carrier bags?

8. Why is PMMA often used for light fittings, illuminated signs and lenses for car lights?

9. Why is LDPE used for carrier bags?

10. State 2 used of PMMA (acrylic)

11. What is HIPs used for?

12. What is epoxy resin used for?

13. What is melamine formaldehyde used for?

14. Urea formaldehyde is often used for plugs, sockets and electrical fittings- why is this?

Plastics- Conversion from raw materialsThe majority of plastics are made from crude oil

but some can be made from plants. The crude oil is

extracted from land or at the sea bed.

Then it is processed using fractional distillation,

this is where it is heated to separate it into

different factions.

Then these factions are combined to form plastics

(this process is called polymerisation). Before this,

some fractions need to be broken down by heating

them using cracking. The plastics are then cut

down into smaller pellets.

Task 10- Converting plastics from crude oil1. What are plastic made from and where is it found?

2. What is fractional distillation?

3. What is polymerisation?

4. What needs to happen to some fractions before the

polymerisation process?

Polymer (plastic) finishing

Usually, plastics are said to be to be ‘self-finishing’ because they do not need additional finishing process once

manufactured (unlike wood and meal). Surface textures on plastics are produced from the mould (during the manufacturing

process).

Adding colours

Adding pigments during manufacture provides colour

Colour pigments are tiny particles which are added during the

manufacturing process to create a particular colour e.g.

pigment particles can be added to the hopper during injection

moulding (with the polymer granules)

An easier way to colour plastics is to buy pre-pigmented

granules (shown beside in the top right) for injection

moulding.

Acrylic spray paints

Fast drying, water soluble paint that becomes water resistant when dry

Used in automotive industry (cars)

They can make the plastics look smoother and also provides protection

against the effects of UV light and weathering. It also allows for mass

customisation (many features can be coloured to a specific customer’s

choice)- automotive industry. i.e. bumpers, wing mirrors, handles

Task 11- Finishing plastics1. Usually, plastics are ‘self-finishing’- what

dies this mean?

2. How are surface textures produced on

plastic products?

3. What are pigments?

4. When are colour pigments added to

plastics?

5. What is an easier way to colour plastic

instead of adding pigments?

6. What are acrylic spray paints?

7. Name an example of a plastic product that

can be spray painted with acrylic spray

paint

8. How does the spray paint improve the

plastic?

9. Spray paint also allows for mass

customisation- why is this important?

Shaping plastics- vacuum forming

The process can be broken down into the

following stages:

1. A mould is put onto the vacuum bed

2. A sheet of heated plastic is then laid

above the mould in clamps

3. The mould is lifted up, at the same time

the air is sucked out of the chamber

4. This forces the heated plastic onto the

mould, copying its shape

5. The plastic is then cooled and becomes

rigid

Vacuum Forming is a method of forming plastic that is common in schools used to produce trays,

cartons, lids etc. This is used in batch or mass production to make food packaging within the

packaging industry. It is done by heating a clamped sheet of thermoplastic until soft, air is then

extracted so that the plastic is sucked down forming a mould. The mould must be shaped so that

it easily comes off it is then tapered so that it has a smooth finish and smoothed edges.

Blow moulding

Step 1

A tube of heated and softened polymer is extruded

vertically downwards. This tube is called a Parison.

Step 2

The mould halves close, trapping the upper end of

the Parison, effectively sealing it.

Step 3

Hot air is then blow into the Parison forcing it out to

follow the shape of the mould.

Step 4

The mould effectively cools the polymer allowing it

to be released from the mould.

Step 5

The mould halves are opened and the product is

extracted.

Advantages:

• Once set up, blow moulding is a rapid method of

producing hollow objects with narrow neck.

• Non-circular shapes can be produced.

Disadvantages:

• Moulds can be expensive

• Its difficult to produce re-entrant shapes, i.e. shapes that

do not allow easy extraction form the mould (e.g. a

dovetail joint).

• Triangular shaped bottles are difficult to produce.

Blow moulding is similar to vacuum forming in that it uses air, but instead of sucking air out, it blows air into a mould.

This is the process used to make plastic bottles. If you look at the bottom of a plastic bottle, the hard circle in the

centre is where the plastic was clamped during the making process.

Injection moulding

Step 1

Plastics granules (and any other additives and colours mixed with

them are placed in the hopper. The granule mixture falls through the

hopper onto the screw.

Step 2

The screw is rotated via the motor and gearbox. This action forces the

polymer forwards towards the heaters, where it becomes softened to

the point where it is ready to be injected into the mould.

Step 3

The hydraulic ram forces the softened polymer through the feedhole

into the mould. Pressure form the ram ensures the mould cavity has

been filled.

Step 4

When sufficient time has passed to allow the polymer to cool and

solidify (a matter of seconds), the mould halves are opened. As they

open, ejector pins are activated to release the product from the

mould.

Step 5

Once emptied, the mould is then closed ready to begin another cycle.

Advantages:

• Very complex shapes can be

produced.

• High volumes can be produced

with consistent quality.

• Metal insets can be included in

the item being produced.

Disadvantages:

• Initial set up costs are high

• Mould are expensive.

Injection moulding is where pellets of plastic are heated and forces into a mould.

It is then left to cool and then removed from the mould.

Extrusion

Extrusion is very similar to Injection moulding, this

method also used pellets that are heated and forced

into a mould

However Extrusion is used to make continuous strips

with a certain cross section such as guttering

This is done by not having a closed mould, instead the

plastic is simply pushed out continuously.

Task 12- Shaping plastics1. What is vacuum forming?

2. What type of products are made using vacuum forming?

3. Explain the stages of vacuum forming

4. What is blow moulding?

5. What types of products does blow moulding make?

6. Explain the stages of blow moulding

7. State two advantages of blow moulding

8. State one disadvantage of blow moulding

9. What is injection moulding?

10. Explain the stages of injection moulding

11. State two advantages of injection moulding

12. State one disadvantage of injection moulding

13. What is extrusion?

14. What types of products are made using extrusion?