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IGCSE DT - Coggle Diagram

- - - - Alongside this, trend forecasting can help identify future demands for timber, and allows us to account for it.
    - - Cutting down the trees mean that they absorb less CO2.
      - Alongside this, the machinery used to cut down the timber produces CO2, and the methods of transport also emit CO2
  - - - Larch is pale coloured, with a contrasting darker grain. it has a lot of knots. It is durable, and easy to machine. It has good water resistance, and is used for external building and flooring.
      - Spruce is a pale cream colour, and is lightweight easy to form. It is used for construction and furniture
      - Pine is pale coloured with an aesthetically pleasing grain. It is lightweight, easy to form and used for construction and decking.
    - - Ash is pale coloured, with a close grain. It is flexible and tough, and is used to make handles.
      - Beech has a pink tint, close grain, and is tough, durable and smooth to finish. It is often used for children's toys as it does not splinter.
      - Mahogany has a dark red colour, and a very close grain. It cuts and polishes easily, and is used for high quality furniture
      - Oak has a mid brown colour, and is used for quality furniture.
      - Balsa is a fast growing hardwood, and is very soft and easy to form, and is used to make models
    - - Strength - its ability to withstand compression, tension and shear
      - Hardness - it's ability to withstand an impact without denting.
      - Toughness - it's ability to be not break or snap, and can absorb shock.
      - Malleability - how easy it is to bend or shape.
      - Ductility - can it be stretched into wires
      - Elasticity - it's ability to be stretched and then return to it's original shape
      - There are also a set of physical characteristics
        
        Knots are spots where the branch grew out of the tree. the grain swirls, and makes the part harder. Knots can also make the wood aesthetically pleasing.
        
        Different woods have different colours.
        
        Grain structure
        
        Hardwoods have two long vessels known as fibres and pores. Softwoods have one cell called tracheids.
        
        You can have close and open grained woods. Close grained woods have many growth rings packed closely together. Open grain woods have fewer growth rings spread apart more.
      - Finally, timbers have social footprints, and this must be considered
        
        We can make use of trend forecasting, to invest in designing and making products for use in the future.
        
        Logging can bring jobs and money to an area, but it also often pushes people out of ancestral honmes.
    - - MDF is a smooth, light brown timber. It is smooth and easy to finish. it absorbs moisture, so is not suitable for outdoor use, and used for kitchens and flatpack furniture.
      - Plywood has an odd number of layers of veneer, glued at 90 degrees. It is very strong, and is used for shelving and construction
      - Chipboard is made of compacted wood chips, laminated with a variety of coverings. It is strong, but absorbent so is used for veneered worktops and flooring
  - - - Regular sections, such as planks, or blocks. These are known as stock sizes
      - Mouldings, a piece of timber that has a decorative pattern along it's length
      - Dowels, a thin long round piece of wood.
      - Sheets, often used for veneers
  - - - Compression - a pushing force.
      - Tension - a pulling force
      - Shear - a force acting across the material
      - To strengthen timber, we can do a number of things
        
        Timber has good tensile and compressive strength, but does not bend. To help this, we can "kerf" the material and cut lengths along it, and glue and compress it. This means that the wood can be bent and withstand the compressive force.
        
        To strengthen a square or rectangle, we can put a diagonal strut or triangle across each corner.
        
        We can laminate a plank, by having the layers at 90degrees to each other. The overlapping grains mean that it becomes harder to snap, and won't flex.
  - - - A router works by rotating a cutting bit at a high speed. They can plunge into material to cut holes, and can follow jigs or patterns. Routers can be CNC controlled to further help with accuracy
    - - Sawing machines can help cut timbers quickly. Circular saws and bandsaws are the most commonly found.
    - - A mortiser makes a square hole for a mortise and tenon joint
    - - A bag press is used to create curved shapes in laminated timber veneers. The bag is sealed, and veneers are pressed against a mould.
  - - - A rip saw, for roughly cutting thicker planks and boards
      - tenon saw - for cutting straight lines with accuracy
      - Coping saws, for cutting thinner pieces of timber
    - - Twist drills, used to drill a hole of a fixed diameter into a piece of timber
      - countersink bits can profile a hole so the top of a screw sits flat.
      - forstner bits cut flat bottomed holes
      - hole saws cut large holes
    - - chiselling, cutting away pieces of timber.
      - planing can smooth the edge of a piece , by running a sharp blade in the direction of the grain.
      - abrasion and sanding can help create a profiled shape or a flat piece of wood.
        
        hand sanding
        
        machines, like a belt, disc or orbital sander
        
        files
        
        rasps, which have larger teeth that leave marks
        
        surforms, which are used for rough shaping
      - turning, using a lathe, creating a uniform circular pattern
  - - - Screws, which create a strong joint and can be unscrewed. We can drill a pilot hole which makes it easier for the screw to go in, and we can countersink it to ensure that the screw sits flush
      - Nails, which are just hammered into timber. They are faster than fitting a screw
      - Adhesives, such as CA and PVA are used. PVA is a wood glue that dries clear, and must be clamped. It produces a permanent and strong joint.
- - - - Batch production is where many items of the same product are produced. Money is saved when compared to the cost of a one-off product.
    - - Mass produced products are manufactured in large volumes often on assembly lines, where standard components are just fit together
    - - Continuous production takes place 24 hours a day, 7 days a week. Timber products rarely have the demand to be produced like this, but stock sizes of timber and paper can be produced using this.