Technological materials,tools and wood

Technological materials,tools and wood

1. Materials and raw materials/Selecting materials

   • the techniques to be used
     • Do we know or can we learn the techniques we need to work with the materials and tools available to us in a reasonable period of time?
   • The type of material
     • Man-made
     • Natural
   • Function
     • Main function
     • Another funtion
   • Durability
   • The kind of addicional elements
     • Which tools must be used? Are joints needed?
   • Cost of materials
     • What is our budget

2. Materials and raw material/Raw materials

   • Are products extracted directly from nature. They may be of plant,animal or mineral origin. Air and water are also considered raw materials and are esencial for crops and life in general

3. Materials and raw materials/Natural and processed materials

   • Industrial processes are applied to raw materials,also known as natural resources,to return them into processed materials.For example the wood from trees is made into planks.

4. The properties of materials

   • Mechanical properties
     • The mechanical properties relate to a materials behaviour when subjected to stress and loads.
       • Hardness
       • Mechanical resistance
       • Toughness
       • Brittleseness
       • Elasticity
       • Plasticity
   • Thermal properties
     • Expansion
     • Thermal conductivity
   • Environmental properties
     • Biodegradability
     • Recyclability
     • Environmental hazard
     • Toxicity

5. Tools

   • For many centuries,humans used their hands as tools, until their brains ability for abstract thought inpired them to use sticks and stones to make their actions more efective
     • Asembly tools
     • Measurement tools
     • Support tools
     • Cutting and levelling tools
     • Impact tools
     • Marking tools
   • What is a tool?
     • There are many different kinds of tools, which are suitable for a wide range of activities. Tools may be be defined as objects designed to carry out mechanical works and tasks.

6. Wood

   • Wood is the fibrous material that trees are made of. It is made up of two main substances: celulose (a natutal fibre that forms the walls of plant cells) and lignin (which holds the cellulose together,making the treee hard andrigid).
   • Parts of tree trunk
     • Heartwood
       • Bark
         • Pith
           • Sapwood
             • Growth rings
               • Cambium

7. Types of wood

   • Depending on the type of tree natural wood comes from
     • Non-resinous
       • This kind of wood mainly comes from trees that have a little resin and a fibrous texture
     • Resinous
       • This kind of wood usually comes from evegreen trees, which produce resin, have white or light-coloured wood and are, in general, quite soft.

8. The properties of wood

   • Flexibility
   • Thermal and electrical insulation
   • Densidility
   • Splitability
   • Sound conductivity
   • Toughness
   • Hardness
   • Hygroscopicy

9. Forms of wood

   • Natural wood
     • Strips
       • Moulding or profiles
         • Boards and planks
           • Beams
             • Panels
               • Sheets or veneers
   • Prefabricated wood
     • It is more uniform
       • It warps less frequrntly
         • It is available
           • Fungicide
             • It is made from trees whose quality is unsuitable for sawing
               • It comes in standard sizes
                 • It is cheaper than natural wood
   • Commercial forms
     • Plywood
       • Chipboard
         • Fibreboard
   • Woodworking tools
     • Basic hand saws
     • Hacksaws
     • Hammers
     • Mallets
     • Spanners
     • Screwdrivers