Core Materials Flashcards
Properties of softwoods
- aka coniferous
- grow in cooler climates (straight/tall, faster)
- loose grain structure (no visible pores, thick fibre content, so easier to work w)
- cheaper/easier to obtain
Example of softwood
PINE:
Properties: lightweight, essy to work w, good elasticity (pale yellowish brown)
Uses: interior construction, furniture
Properties of hardwoods
- aka deciduous
- grow in temperate climates
- tighter grain structure (visible pores, thinner fibre content, so harder to work w)
- slow growing, expensive
Example of hardwood
OAK:
Properties: tough, hard & durable, heavy & dense (light brown)
Uses: flooring, furniture
What is a ferrous metal
Contains iron, so magnetic but vulnerable to rust if exposed to moisture w/o finish. High tensile strength & durability
Example of ferrous metal
LOW CARBON STEEL (mild steel):
Ferrous of iron/carbon. Cheap, lightweight, tough & ductile. Strong magnetic properties, rusts easily if not protected
Uses: car bodies, pipelines
What is non-ferrous metal
Pure metals, not magnetic as dont contain iron. Higher resistance to rust but can corrode/oxidise
Example of non-ferrous
COPPER:
Ductile, malleable, good electrical conductor
Uses: plumbing supplies, electrical cables/wires
What is an alloy
Mixture of 2 or more diff metals to improve properties (physical/mechanical). Harder than pure metals as contains atoms of diff sizes. Distorting arrangements of atoms makes harder for lauers to slide over.
Example of alloy
STAINLESS STEEL:
Composed of low carbon/chromium. Hard, ductile, rust resistant. Chromium layers protect steel from corrosion
Uses: cutlery, kitchen & medical equipment
Absorbency
Ability to soak up/drawn in heat, light, moisture
Fusibility
Ability to be converted from solid to liquid by heat & combined w another mat
Ductility
Ability to be stretched w/o breaking
Strength
Ability to withstand forces s/a pressure
Toughness
Ability to absorb shock w/o fracturing
What are polymers
Long chain molecules made from small repeating units called monomers
Originate from crude oil (finite resource, non-renewable)
What are thermoforming polymers
Involves using heat to form thermoplastics. Flexible esp when heated.
Polymer chains loosely entangled w very few cross links - allows chains to easily slide over eachother when heated. Can be reformed multiple times
O-O-O
O-O-O
Example of thermoforming polymer
ACRYLIC (PMMA):
Tough but brittle. Easily scratched, resistant to weathering
Uses: car lights
What are thermosetting polymers
Involves using chemical reactions to form plastics, cannot be reformed. Resistant to higher temps (burn rather than melt)
Chains rigidly cross-linked
O-O-O
\ \ \
O-O-O
Example of thermosetting polymer
EPOXY RESIN:
Good strength to weight ratio. Good electrical insulator, heat resistant
Uses: adhesives
What are manufactured boards
Usually made from timber waste & adhesive, often veneered for more aestheticslly pleasing finish
Manufactured boards: MDF
Rigid & stable, smooth to finish surface. Very absorbent so not suitable in high humidity or for outdoor uses
Uses: kitchen uses
Manufactured boards: Plywood
Very stable in all directions due to alternate laying at 90 degrees, w outside layer running in same direction
Uses: shelving, construction
Manufactured boards: Chipboard
Good compressive strength, not water resistant, prone to chipping on edges/corners
Uses: flooring, worktops
Adv of manufactured boards
- available in large board sizes - reduces no. of joints
- cheaper than natural timber
- can be laminated to apply wide range of finishes
Disadv of manufactured boards
- resins and binders in boards can be toxic - precautions must be taken
- edges difficult to finish due to no natural end grain
What are textiles?
Derived from natural & synthetic mats. Highly adaptable & can be constructed to maximise properties
Eg of natural fibre
COTTON:
Prop: soft, absorbent, washes
Uses: clothes, towels
What are natural fibres?
Made from plant or animal based fibres (renewable)
