packaging project

MIG welding

Electric current melts metals to weld together
sheilding gas- protecs from impurites in the air to creat a tidy and stronger bond
Electris current makes a molten pool of metal thenthe welder feeds a wire of mild still into a hole so it makes a join in the metals.

When you pull the triger a shrouding gas comes out then the wire is feed out more and melts onto the metal to you are joining
when welldig make sure you are comfortable.

higher ampabe more power weld is created faster

Metals

used to be most used material but has changed now
4 metals
ferous
non ferous
ferouse alloy
non ferous alloy
ferous metals contain iron
and carbon can rust and oxedise
non ferous don't contain iron
alloy is a mixture of metales

woods

we use maufactured board rather than wood because
wood may still be moisture
widely avalable
comes in multiple of 3mm
1.24 high 2.44wide
woods can be madestronger by placing grains in different ways.

MDF
medium density fiberboard
HDF
high dencity fiberboard
made by wood chippings an adehsive. being compresed
hard to cut and blunt the blade.

Chipboard
used in kitchens
usually a coating is aplied to top to make it look good
cost affective

Blockboard
wood sandwiched between two vaners

Aeroply
used arcraft expensive

Maplex
new type of mdf used in furniture
easy to machine

Plywood

Slice venering making vaners of wood

Types of finishing
most woods need protection especally for another use

vital always say a product is finished
type are
Polyurethane varnish most common type protect surface
Wood satain color dosent protect wood so you need to apply protective coat affter
Oils rubbed in the maintain natural apperance
Preso
Paint color protect wood
injecting a wood with tanalise.
this is why some wood look green
only inject 5mm all edges of the wood
called tanaliseing
protects wood 4 times as long

woods

timber is wood that has been cut down and then processed
a lumber is where the treee has just been harvest
the twn types of wood are hardwoods and soft woods
annual rings gives u a idea of how old the tree is
1 anual ring is 1 year of growth
wood is fiberous fibers run along the length
of the trunk
55%tree is celluous and 28%is resin

prosses from lumbering to wood
harvesting cutting tree down
connversion cutting trunk to boards
seasoning redusing mouisture content
board preperation sawing size par (planning all round)

slab or plain sawing uses the whole tree but wood may curve slightly
quater saw timber more waste less stable less reliable and warp and twist
par planned all round square edge

things to cosider with wood
phisical strength
asthetics
moisture
protection
operating conditions
costs
sustainability/enviromental issues fse (forestry steward ship concil)
size of boards avalible

2 main types to dry woods
air drying is cheep easy but takes a long time
kiln drying alot faster fast tern around but expensive
hardwoods come from deciduous tree
soft wood come from conivourous trees.

hardwoods
ash beach oak teak walnut

softwoods scotspine larch spruce

laminating

somthing that's built up of layers is laminated

the prosses of joining the layers together is called laminated
plastic laminated is made of composite layers of papper and plastic
wood is laminated sometimes so you can bend it into shapes
there are 2 main methods how to laminat woods
laminating using a male and female moulds
laminating using a vacume bag of vacume frame
it take about an hour to steam bend 25mm ash approxmately
an alternative way of making curved sections of wood is

steam bending

ash is the most common material used in steam bending

the primary attribut of bent wood is that its grain runs continuosly along its entier length. if the bendis made across more than 1 axis the timber will be twisted to align to the grain

the main advantage of berch wood is it strength which means parts are lighter