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Woods can be divided into Three main categories soft and hardwood and man made boards. softwood trees are coniferous – cone bearing, have thin needle-liked.

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Presentation on theme: "Woods can be divided into Three main categories soft and hardwood and man made boards. softwood trees are coniferous – cone bearing, have thin needle-liked."— Presentation transcript:

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2 Woods can be divided into Three main categories soft and hardwood and man made boards. softwood trees are coniferous – cone bearing, have thin needle-liked leaves and are evergreen Grow relatively quick they reach maturity within 30 years Cheaper than hardwoods Examples: pine, spruce, douglas fir

3 relatively cheap strong lightweight easy to shape with hand tools can be oiled/varnished or painted.

4 Attractive, very durable, strong, heavy material which can be oiled/varnished/waxed. Commonly used in furniture and flooringfurniture Beech is classed as heavy, hard, strong, high in resistance to shock and highly suitable for steam bending. Good resistance to abrasive wear. Beech is easy to use with most hand and machine tools. It has good nailing and gluing properties and can be stained to a good finish. Widely used for furniture framing and carcass construction, flooring and engineering purposes.

5 Hardwood trees are deciduous (lose there leaves annually) - big leaves Very slow growth can take 100 years to mature More expensive Examples: mahogany, beech, elm,oak, ash, teak

6 MDF is a type of wood formed by broken down and powdered softwood, which is mixed with wax and resin. This is then formed by applying high temperatures to the MDF products to create the finish. It is cheap and has a good surface finish which can be painted to give a good effect. Plywood is a type of engineered board made from thin sheets of wood, called wood veneers. The layers are glued together, each with its grain at right angles to adjacent layers for greater strength and the grain on the outside surfaces runs in the same direction. The venners are joined under heat and pressure with strong glues, making plywood a type of composite material. Its cheap comes in large sheets, it is resistance to cracking, shrinkage, twisting/warping, and its generally strong and it is made from scrap wood.engineered boardwoodwood veneerscomposite material Man made woods are made from bits of scrap wood which is stuck together by man M edium D ensity F ibreboard

7 A sustainable forest is a forest that is carefully managed so that as trees are felled they are replaced with seedlings that eventually grow into mature trees ADVANTAGES skilfully managed system. producing wood products such as wood pulp for the paper / card industry and wood based materials for furniture manufacture and the construction industry. Great care is taken to ensure the safety of wildlife and to preserve the natural environment.

8 Metals can be divided into THREE main categories FERROUS, NON FERROUS AND ALLOYS.  Ferrous metals contain iron  Examples are cast iron, mild steel, medium carbon steel, stainless steel, and high speed steel.  Non-ferrous metals do not contain iron.  Some common non-ferrous metals are aluminium, duralumin, copper, zinc, brass, and tin.

9  An alloy is a mixture of two or more elements, at least one of which is a metalelementsmetal  Alloying one metal with others often enhances its properties  Steel is the most common alloy (iron and carbon)

10 Aluminium – Good strength, light, soft, easy to bend, doesn’t rust, good conductor of heat and electricity. Generally used in Kitchen equipment, window frames, general cast components. conductor Stainless Steel - Hard and tough, resists wear, heavier than aluminium and it does not rust. There are different grades and surface finishes of stainless steel to suit the environment to which the material will be subjected in its lifetime. Common uses of stainless steel are cutlery and watch straps, and outdoor furniture.cutlerywatch

11 PLASTICS can be divided into TWO main categories THERMOPLASTIC and THERMOSETTING plastic. recyclable Don’t resist heat very well Easily shaped and reshaped Examples: acrylic eg (toy’s), ABS (bumpers), polystyrene (packaging) and polythene (bags) Non-recyclable resists heat and fire very well Easily shaped Examples: epoxy resin (adhesive), urea-formaldehyde, polyester resin.

12 Polyesters (PET) is produced in numerous forms such as sheets and three-dimensional shapes. thermoplasticsthermoplastics may change shape after the application of heat, it is strong, lightweight and waterproof. USE: home furnishings such as bed sheets, bedspreads, curtains, ropes, fabrics for conveyor belts, safety belts, coated fabrics and cushion padding. Durability: its high tenacity fibbers are used for seatbelts, tire cords, ballistic cloth and other uses. High elongation, excellent abrasion resistance, highly resilient (nylon fabrics are heat-set) High resistance to: insects, fungi and animals, molds, mildew, rot, many chemicals and rain

13 QUESTIONS Complete this summary table about softwood? Definition of SoftwoodMost softwoods are coniferous (cone bearing). They typically have thin needle-like leaves and are evergreen Rate of growth Cost (in relation to Hardwoods) Give three examples

14 QUESTIONS Briefly explain why making wooden products out of softwoods rather than hardwood is generally better for the environment. Describe what manufactured boards are and give two examples?

15 QUESTIONS (c) In simple terms - explain the nature of a sustainable forest. (d) In your opinion, why is it important to support sustainable forestry.

16 QUESTIONS Give two (2) advantages of manufactured boards? Give two (2) disadvantages of manufactured boards? Cheap, environmentally friendly, comes in large sheets, good surface finish which can be painted to give a good effect. What does MDF stand for? Unattractive appearance without a surface finish, low quality Medium Density Board

17 QUESTIONS Complete the following table about metals. Definition of a non ferrous metal These are metals that do not contain iron and therefore do not rust Rust or not Will not rust Give three (3) examples aluminium, duralumin, copper, zinc, brass, and tin. Definition of a ferrous metal Ferrous metals contain iron Rust or not Will Rust Give three (3) examples cast iron, mild steel, medium carbon steel, stainless steel, and high speed steel.

18 QUESTIONS Describe briefly what an alloy is? An alloy is a mixture of two or more elements, at least one of which is a metal. The mixing of elements often improves its propertieselementsmetal

19 QUESTIONS What are the names of the two (2) basic groups of plastic? Thermoplastic and Thermosetting plastic Complete this summary table about Thermosetting plastics? Definition of a thermosetting plastic Thermosetting plastics are generally strong and resistant to heat. Once formed into a shape they can not be re-shaped. Recyclable or Non Recyclable NON RECYCLABLE Give four (3) examples epoxy resin, urea-formaldehyde, polyester resin

20 QUESTIONS Name two (2) thermoplastics and give an use for each? acrylic, ABS, polystyrene and polythene


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