CORE TECHNICAL PRINCIPLES

Define absorbency and give an example

-Ability of a material to soak up moisture or draw in heat
- Eg cotton is more absorbent than acrylic

Define density and give an example

- The mass per unit vol of any material, solidarity of a material
- Eg polysyrene has LD suitable for packaging

Define electrical conductivity and give an example

- The measure at which a material can transport elec
- Copper is a good conductor of elec yet plastic/rubber isn't

Define fusibility

The ability of a material to be converted
from a solid to a fluid state by heat and
combined with another material

Define thermal conductivity and give an example

- The ability of a material to be converted
from a solid to a fluid state by heat and
combined with another material
- Eg Copper is an good conductor of heat

Working properties

Describes how a material responds when it is manipulated or worked

Define ductility and give an example

- The ability of a material to
be stretched or drawn or
pulled without breaking.
- Eg Copper is ductile so can be
drawn out to make wire.

Define elasticity and give an example

- The ability to return to
its original shape after
stretching or compression.
- Eg Lycra is used for sportswear
to provide freedom of
movement.

Define hardness

- The ability to withstand
impact, wear, abrasion and
indentation.
- Eg Tungsten is hard, used for
knives, drills and saws.

Define malleability

- The ability to be bent and
shaped without cracking or
splitting.
- Eg Gold, copper, silver and
lead can all be easily
hammered into shape.

Define strength and give an example

- The ability to withstand
a force such as pressure,
compression, tension or
shear.
- Eg Concrete is
strong under compression,
but not tension.

Define toughness and give an example

- The ability to absorb shock
without fracturing.
- Kevlar impact body armour absorbs

What's paper measured in and usual weight range

- GSM
- 60-170gsm

Properties and uses of layout

- Medium opacity
sheet with a
smooth finish.
60-90 gsm.
- Sketch and
design work.

Properties and uses of tracing

Properties:

Off white, low

opacity sheet.

60-90 gsm.

Uses: Copying,

overlays and

tracing drawings

Properties and uses of cartridge

Properties:

Thick white

paper with

a textured

surface.

120–150 gsm.

Uses: Sketching,

watercolours,

ink drawings.

Properties and uses of bleed proof

Properties:

Thick white

paper with

a textured

surface.

120–150 gsm.

Uses: Sketching,

watercolours,

ink drawings.

Properties and uses of grid

Properties:

White paper

with a printed

grid of squares,

isometric lines or

other patterns.

80–100 gsm.

Uses: Scale

drawings, model

making, scientific

diagrams.

CARDS AND BOARDS

measured in thickness (microns)

Properties and uses of corrugated card

Properties: Two layers of

lightweight card containing

a fluted layer for strength.

Uses: Packaging for

impact protection and

insulation. Fully degradable

and recyclable.

Properties and uses of foil lined

Properties: Card coated

with aluminium foil on one

side. Foil retains heat keeping

contents warm and creates a

moisture barrier.

Uses: Takeaway containers.

Properties and uses of duplex

Properties: Two layers of card bonded

together, often with a white external layer.

Available with metallic and holographic

finishes.

Uses: Tough, with a bright white appearance

suitable for packaging. Used with a waxy

coating for food and drink containers.

Properties and uses of foam core

Properties: An inner foam

core with a paper face.

Rigid and stiff.

Uses: Model making and

mounting artworks.

Properties and uses of ink jet

Properties: Treated card

with smooth finish and bleed

proof printable surface.

Uses: Printing photographs

and artworks.

Properties and uses of solid white

Properties: High quality card, brilliant white

smooth finish on both sides.

Uses: Greetings cards, quality packaging

and book covers.

Natural timbers

come from deciduous tree, that drops leaves in winter

Ash

Properties: Flexible, tough and shock resistant,

laminates well. Pale brown.

Uses: Sports equipment and tool handles.

Beech

Properties: Fine finish, tough and durable. Beige

with pink hue.

Uses: Children’s toys and models, furniture, veneers.

Mahogany

Properties: Easily worked, durable and finishes well.

Reddish brown.

Uses: High end furniture and joinery, veneers.

Balsa

Properties: Very soft and spongy, good strength to

weight ratio. Pale cream/white.

Uses: Prototyping and modelling.

Oak

Properties: Tough, hard and durable, high quality

finish possible. Light brown.

Uses: Flooring, furniture, railway sleepers, veneers.

Softwoods

come from coniferous trees, usually has needles and cones

Pine

Properties: Lightweight, easy to work, can split and be

resinous near knots. Pale yellowish brown.

Uses: Interior construction, furniture.

Spruce

Properties: Easy to work, high stiffness to weight ratio.

Creamy white.

Uses: Construction, furniture and musical instruments.

Larch

Properties: Durable,

tough, good water

resistance, good surface

finish. Pale reddish brown.

Uses: Exterior cladding,

decking, furniture and joinery.

Manufactured timbers

Usually sheets of processed natural timber waste
products or veneers combined with adhesives.

They are made from waste
wood, low-grade timber and recycled timber.

Chipboard

Properties

Good compressive strength, not water

resistant unless treated, good value but

prone to chipping on edges and corners.

Uses

Flooring, low-end furniture, kitchen units

and worktops.

MDF

Properties

Rigid and stable, with a smooth, easy to

finish surface.

Very absorbent so not good in high

humidity or damp areas.

Uses

Good value, flat pack furniture, toys,

kitchen units and internal construction.

Plywood

Properties

Very stable in all directions due

to alternate layering at 90°. Layers run in same direction.

Uses

Furniture, shelving, toys and

construction.

Ferrous

contain iron ferrite and have high strength and durability

Cast iron

Properties

Hard but brittle. Resists

deformation and rust.

Uses

Kitchen pans, machine

bases, manhole cover

low carbon/ Mild steel

Properties

Tough and ductile. Rusts

easily if not protected.

Uses

Car bodies, steel building

frames, pipelines.

High carbon steel

Properties

Hard, but brittle.

Hard wearing, resists

abrasion and retains

its shape.

Uses

Tools, blades, scissors.

Non ferrous

pure metal containing no iron. errode or oxidise easily

Aluminium

Properties: Lightweight, ductile,

resists corrosion.

Uses: Bike frames, drinks cans,

takeaway trays.

Copper

Properties: Ductile and malleable. Good

electrical conductor.

Uses: Plumbing supplies, electrical cables.

Alloys

a mixture of at least one pure metal and another element.

Stainless steel

Properties

Hard, ductile. Rust resistant.

Chromium layer protects

steel from corrosion.

Uses

Cutlery, kitchen and

medical equipment.

Brass

Properties

Malleable and easily cast.

Good corrosion resistance.

Uses

Musical instruments,

plumbing fitments and

ornate artefacts.

THERMOFORMING POLYMERS

Polymer
chains are quite loosely entangled with very few cross links.

This allows the
chains to easily slide past each other when heated.

They can be formed into
complex shapes and reformed multiple times.

Acrylic

Properties

Tough but brittle when thin.

Easily scratched, formed and

bonded.

Uses

Car lights, alternative to glass,

modern baths, clothing.

Polypropylene

Properties

Flexible, tough, lightweight, food safe.

Uses

Kitchen, medical products, rope.

THERMOSETTING POLYMERS

Undergo a chemical change and once formed or
set, cannot be reformed.

Thermosets are resistant to higher temperatures but
tend to burn when heated rather than melt.

They are harder, more brittle and
provide good insulation and chemical resistance.

Polyester resin

Properties

Good electrical

insulator, hard, but

becomes tough when

mixed with glass

strands to form glass

reinforced plastic (GRP).

Uses

Encapsulation, boat

hulls as GRP.

Epoxy resin

Properties

Good strength to weight ratio, good

electrical insulator, heat resistant.

Uses

Bonding waterproof coatings,

electronic circuit boards.

TEXTILES

Derived from natural and synthetic materials.

Natural

Made from plant- or animal-based fibres and are renewable.

Cotton

Properties

Soft, strong, absorbent. Washes

and takes dyes well.

Uses

Range of clothing, towels, bed

sheets.

Silk

Properties

Soft, fine, lightweight. Natural

shine due to its triangular

structure.

Uses

Luxury clothing, underwear, ties,

wall hangings, night clothes.

Synthetic fibres

Made from chemically produced polymers.

Polyester

Properties

Tough, strong, hard wearing, non-

absorbent.

Uses

Fleece, backpacks, threads, sportswear.

Blended fibres

Combine
two or more types of fibre to produce
a fabric with useful properties.

Polycotton

Properties

Durable and stronger than pure

cotton. Reduces creasing.

Uses

Clothing and bed sheets.

Woven cloth

Made up of two sets of
yarns which are threaded at 90 degrees to
each other.

The warp threads are fixed in
the loom and run the length of the fabric.

The weft threads run across the width of
the fabric.

Plain weave

Properties: Strong, hard-wearing,

retains shape. Even surface on both

sides. Different yarns can create hard

wearing weave.

Uses: Tablecloths, upholstery, clothing.

Non woven fabric

Made directly from fibres without being spun into yarns.

Bonded fabric

Properties: Fabrics lack strength, they have

no grain so can be cut in any direction and do

not fray.

Uses: Disposable hygienic clothing, cloths, teabags.

Knitted fabric

Technique of interlocking yarn

loops together to produce a fabric.

Used for

jumpers, socks, tights, and soft toys.

Weft knitting

The loops are made as yarn is added in the crosswise direction

Warp knitting

Yarn moves vertically in the fabric