Hard wood, Soft wood

Hardwood
Deciduous tree, looses leaves in autumn
Ash, Oak, Beech, Teak, Walnut

Softwood
Coniferous trees, has needles or cones
Larch, Spruce, Scots Pine, Douglas Fir

Wood laminating

Wood Laminating



Laminating - something thats built up in layers

Vaneer - Often used in laminating



Plywood is made from thin sheets of wood, called veneers which are glued together.



Plastic laminated - many layers of resinimpregnated kraft paper.



When wood is cut into thin veneers it can be bent into a mould to form complex shapes.





Laminating Methods

- Using male and femail mould

- Using a vacuum bag or vacuum frame



Using a Vacuum bag - Layers of veneer placed together on a mould and put inside a tough plastic bag. Vacuum pump is used to suck air from bag and produce shape.





Steam Bending

-Creates curvs in wood

Uses steam to eaken the wood so that after it is taken out the machine it is very easy to bend. This happens as the lignin is weekened so the fibres can move more easily. Lignin then sets again.

This process can be done more than once.





Static and Dynamic loads

- static, doesnt move

- dinamic, does move

Planes (dinamic); made out of alluminium which expand when in the air due to a lot of air pressure



Steam Bending

Cost
-low tooling cost
-moderate to high unit cost



Quality
-Good quality and high strength due to grain alignment

Typical Applications
-Boat building
-Furniture
-Musical instruments

Related Processes
-CNC machining
-Wood laminating

Suitabilty
-One-off to high volume production

Speed
-Slow cycle time (up to 3 days)

Pop art - Childrens chair

Wood

- Ceramics; made from clay.

Timber – A sustainable natural resource
Soft wood – Coniferous trees, grow quicker, cheaper
Hard wood – Slow growing, deciduous, slow growing, more expensive

Wood is fibrous with fibres running along the length of the trunk.

- 55% cellulose (fibres), 28% lignin (glue)

- Fibre reinforced polymer

Life cycle up until production:

- Harvest

- Conversion, cutting into boards

– Slab sawn or Quarter sawn

- Seasoning

– Reduce moisture content

- Board Preparation

– Sawing to size, planning

Quarter saw timber – cut the wood so all the pieces got shorter annual rings, more waste but more stable.

Slab saw – Simply cut in lines so there is no waste however you get some pieces with big annual rings. Less waste, less stable.

Need to think about natural timber:

- Physical strength; stronger along the grain than across it

- Aesthetic properties; colour, complex or simple grain structure

- Protection; Dry and wet rot, insect attack

- Operating conditions; Where will the timber be used? Outside? Inside a heated house? -

-Sustainability/ Environmental issues; Use sustainable sources

- Size of boards available

I should never have purchased

Headphones
A few weeks ago my ipod headphones broke so i invested in a new basic pair. The packaging explained that they were durable and would last me at least 6 months but also give out high quality sound.

The headphones aesthetics were of good quality as the ywere just simply black and simple, there was also a small headphone design in the earpiece which advertised the individuality of the set. Another plus point in the headphones that many others fail to have is a wire that is plenty long enough to reach both ears from the inside of your trouser pocket without being tugged from your ears.

However although the aesthetics and wire length was very good the headphones were actually of very poor quality. The sound was nowhere near as good as it had been advertised as it was crackly and broken sound. Due to poor wire connection the sound was also constantly cutting out and has to be positions perfectly in order for them to work. This of course is and inconvenience when you want to listen to music whilst exercising.

It was obvious that very little anthropometric data was taking into account during the production of these headphones. This was clear as it took great care to insure the main ear piece stayed in the place even when doing something simple like sitting down, so it was near enough impossible to take up any physical activity at the same time.

The only solution to this was to chuck them away and buy a new pair, which this time are of good quality.