Materials general information (Timbers, Metals and Polymers) Flashcards
Softwoods features
Grow in cooler climates
Looser grain structure, needles or scale like leaves. Bear cones.
Used as a building material
Softer and easy to work with
Trees grow tall and straight so it is easier to cut.
Faster and cheaper
Hardwood features
Deciduous trees lose there flat leaves in winter
Have a tighter grain
More expensive than softwood.
Found in tropical countries.
Quite hard
Take 100 years to grow
Coniferous trees
These create softwoods and they are evergreen and grow quite fast.
Deciduous trees
These create hardwoods
Manufactured boards features
Available in many thicknesses, cheaper than both, covered in a thin layer of wood, timber sheets are produced by gluing wood layers or wood fibres together.
Used by waste woods
Developed for industrial productions
Softwood examples
Larch, Pune and Spruce
Hardwood examples
Ash, Beech, Mahogany, Oak and Balsa
Manufactured boards examples
MDF, Plywood, Chipboard.
Where do polymers come from?
Come from crude oil. Plant oils produce bioplastics.
Properties of polymers
Coloured,self finishing, can be shaped and formed, reasonable cost and versatile
Thermoforming Polymers definition
Can be formed in different ways and heated
Pros and cons of thermoforming polymers
Recyclable, aesthetically-superior finishes, high impact resistant, can re-shape and eco-friendly
Cons: more expensive than thermoset
Thermoforming polymers examples
High-impact polystyrenes HIPS,High-density polythene HDPE, Polythylene terephthate PET, Acrylic PMMA, Polypropylene PP, Polyvinyl Chloride PVC
Thermosetting polymers definition
Cannot be reheated and formed again.
Pros and cons of thermosetting polymers
Resistant to high temperatures, flexible design, thick to thin wall capabilities, aesthetic appearance, dimensional stability, cost-effective
Cons: not recycled, difficult to surface finish, cannot be remoulded/reshaped.
Thermosetting polymers examples
Urea Formaldehyde UF, polyester resin, exposy resin, Melamine Formaldehyde MF, Phenol Formaldehyde PF
Photochromic pigments
UV light stimulates particles in a special pigment.
For novelty goods and colour changing paints.
Applications of photochromic pigments
Lenses in sunglasses
Security markers seen in uv light
Photochromic windows change transparency
Thermochromic pigments
Fever scan strips used on infants, room thermometers, children’s cutlery and crockery, novelty goods and colour changing clothes.
Two types of metals
Ferrous contains iron magnetic and non ferrous doesn’t
Ferrous features
Contains iron so magnetic
Prone to corrosion
Properties: hard, malleable
Non ferrous properties
Doesn’t contain iron so not magnetic
Majority not magnetic but good for wiring and electronic devices
More malleable and resistant to corrosion than ferrous
They are much lighter than ferrous metals
Ferrous examples
Cast iron, low carbon steel and high carbon steel
Non ferrous metals examples
Aluminium, copper and zinc
Alloys what are they and properties
Formed by mixing two or more metals to produce a new metal.
Adjust mechanical and physical properties for particular purposes.
Can be ferrous and non ferrous
Examples of alloys
Brass, pewter and solder
