Technical Principles Flashcards
What are the dimensions of A4, A3, A2, A1?
A4 - 210 x 297 mm
A3 - 297 x 420 mm
A2 - 594 x 420 mm
A1 - 841 x 594 mm
What are the 4 most common types of paper?
Layout paper
Tracing paper
Copier paper
Cartridge paper
What are the characteristics of Layout paper?
used for sketching and developing designs
smooth surface for both pen and pencil
around 50gsm
thin enough to trace and copy parts of design
cheap
What are the characteristics of Tracing paper?
used for making copies of drawings and fine details
thin and transparent
around 40gsm
hardwearing and strong
mistakes in pen can be scratched off using a sharp blade
What are the characteristics of Copier paper?
used mainly for printing, photocopying and general office purposes
around 80gsm
smooth surface - ideal for printers and copiers
What are the characteristics of Cartridge paper?
available from 8-140 gsm
thicker and more expensive than layout and copier paper
slightly textured and creamy
used by artists
ideal for crayons, pastels, water colour and inks
What is virgin fibre paper?
paper made entirely from new wood pulp
Why has the production of virgin fibre paper decreased?
recycling is cheaper and better for the environment
What are characteristics of card?
thicker than paper at around 180-300 gsm
available in many colours
thin card is easy to cut fold and print on
used for modelling and paperback book covers
What are characteristics of cardboard?
available in many different sizes and finishes
widely used for packaging
relatively inexpensive.
can be used for modelling
around 0.3 mm in thickness
What are the characteristics of corrugated cardboard?
strong but lightweight
made by 2 layers of card with a fluted sheet between
flute construction makes it difficult to bend
shock absorbent
insulating
used as packaging
pizza boxes
>3mm in thickness
What are the differences between hard and softwoods?
hardwoods come from deciduous, softwoods come from coniferous.
hardwoods are more expensive as they take longer to grow back.
generally harder and stronger
What are the differences between coniferous and deciduous trees?
coniferous are mostly evergreen, have needle-like leaves, and bear cones
deciduous mostly shed leaves each autumn, typically flat leaves
What are anomalies in softwoods and hardwoods?
balsa which is a soft hardwood
Larch which is a moisture/nature resistant softwood
What are hardwoods and softwoods mostly used for?
hardwoods - outdoor, durable products, cricket stumps
softwoods - interior products, boxes, furniture
What are some finishes for natural timbers?
wood stain
wood preservative
varnish
oil
paint
What are the 2 main functions of finishing?
protect the timber and enhance its appearance
What are the 2 main types of manufactured boards?
laminated and compressed
What are the differences in laminated and compressed boards?
laminated are produced by gluing large sheets or veneers together
compressed boards are manufactured by gluing, particles chips or flakes together under pressure
What are some examples of manufactured boards?
Plywood, MDF, Chipboard, Hardboard
What does MDF stand for?
Medium-Density FIbreboard
What are characteristics of plywood?
consists of a number of layers of wood glued together.
very strong, flexible board
What are characteristics of MDF?
common, cost-effective
made from fine particles of wood made from recycled timber
very flat surface but easily affected by moisture
What are characteristics of Chipboard?
made by compressing chips of wood together with resin
cost-effective
often veneered with natural timbers to improve appearance
What are characteristics of hardboard?
low cost
generally used in packaging and backing for products such as wardrobes and drawers
one smooth surface, one meshed surface
little strength and easily affected by moisture
What is different about finishes for manufactured boards?
due to their porous nature, they have to be sealed before they can be finished (e.g. with a thin layer of PVA glue)
Can get veneer finish with a layer of natural timber
What are differences between ferrous and non-ferrous materials?
ferrous contain iron which makes them magnetic but also prone to rusting.
Non-ferrous are more malleable, resistant to corrosion and because they aren’t magnetic, they can be used in electronic devices
What are characteristics of alloys?
have two or more elements
usually much stronger and less malleable than metals
formulations to give desirable traits
What are thermosetting polymers?
What are thermoforming polymers?
most commonly used and can be moulded into almost any shape by heat.
can be repeatedly reshaped
What are some examples of ferrous metals/alloys?
steel
stainless steel
Cast iron
What are some example of non-ferrous metals/alloys?
aluminium
copper
silver
What are some examples of thermoforming polymers?
Polystyrene
Low-density polythene (LDPE)
High-density polythene (HDPE)
What are the difference in between LDPE and HDPE?
LDPE is tough and flexible that can be easily moulded into shape. carrier bags, bin liners, washing up liquid bottles are often made of LDPE
HDPE is harder, stiffer and is used for milk crates and wheelie bins
What is polystyrene used for?
it is a food safe polymer so is used for disposable plates and cutlery
What are thermosetting polymers?
they can also be shaped by heat, but only once. They cannot be reheated or reformed making them heat resistant.
What are some examples of thermosetting polymers?
Melamine formaldehyde (MF)
Urea formaldehyde (UF)
Polyester resin (PR)
Epoxy resin (ER)
What is MF used for?
picnic crockery as it is hard and scratch resistant
What is UF used for?
electrical fittings as it is heard-wearing, durable and non-conductive
What is PR used for?
bond together strands of glass fibres to produce tough water proof mouldings such as the hull of a yacht
What is ER used for?
commonly found in school workshop and are used as an adhesive to glue together dissimilar materials
What are natural polymers?
come from plants and animals making them renewable unlike other polymers made from crude oil
What are some examples of natural polymers?
Cotton
linen
silk
wool
