Hardwood and Softwood Timber Types

1.1 Timber (Hardwoods)

• Hardwoods come from broad-leaved trees.
• Balsa, despite being a hardwood, is soft, with low density and lightweight, making it suitable for model making.
• Beech has a straight grain and fine texture, making it easy to work with and suitable for chopping boards, tools, and children's toys.
• Mahogany is durable, stable, and has a rich, dark red color, used in musical instruments and cabinets.
• Oak is a common, hard, and wear-resistant hardwood with an attractive grain, containing tannic acid that corrodes steel fixings, used in furniture and barrels.
• Jelutong has a soft, spongy texture, easy to work with hand tools, low density, and lower durability compared to other hardwoods.
• Hardwoods tend to have a closer grain, allowing for better carving with less splitting compared to softwoods.
• Use the acronym "BOMBJ" (Balsa, Oak, Mahogany, Beech, Jelutong) to remember the five hardwoods.

1.1 Timber (Softwoods)

• Softwoods are cheaper and faster growing than hardwoods.
• Larch is hard, tough, waterproof, but prone to splitting, requiring pre-drilling for use in building and fencing.
• Pine has a straight grain, is knotty, susceptible to rotting, lightweight, and of low density, making it suitable for construction and furniture.
• Redwood is lightweight with good strength, used in structural components and internal decorative milling like architraves.
• Cedar has natural resistance to decay and insect infestation, making it suitable for outdoor applications like cladding and sheds.

1.2 Metals (Ferrous Metals)

• Mild steel contains approximately 0.3% carbon, is ductile, has high tensile strength, is tough, malleable, and has poor corrosion resistance; used in bolts, car bodies, and white goods.
• Medium carbon steel contains about 0.7% carbon; harder than mild steel but less ductile, machinable, and tough; used in gardening tools.
• Cast iron contains around 3% carbon; has a hard outer skin with a brittle core; good under compression; used in machine parts.
• Ferrous metals are magnetic, can rust, and contain iron (ferrite).
• Strength and hardness increase with carbon content in ferrous metals.

1.2 Metals (Non-Ferrous Metals)

• Aluminum is lightweight, ductile, and malleable, used in drink cans aircraft bodies, and bike frames.
• Copper is fatigue resistant, malleable, and ductile, suitable for electrical wires and pipes.
• Tin is ductile and malleable, used in soft solder and as a protective coating for food cans to prevent steel rusting.
• Zinc has good corrosion resistance, used in buckets, as a protective coating (galvanizing), and in die casting.
• Use the acronym "AZTZ" (Aluminum, Zinc, Tin, Copper) to remember these four nonferrous metals.

1.2 Metals (Alloys)

• Stainless steel is tough, hard, corrosion-resistant, smooth, and non-porous, made from chrome, nickel, silicon, and manganese; used in kitchenware like sinks.
• Duralumin is lightweight with high strength, made from aluminum, copper, and magnesium; used in vehicle and aircraft parts.
• Brass is corrosion-resistant, an electrical and thermal conductor, and castable, made from 65% copper and 35% zinc, used in door furniture, ornaments, and taps.

1.3 Polymers (Thermoplastics)

• Thermoplastics can be repeatedly reheated and reshaped, unlike thermosets.
• Acrylic is tough, hard, chemically resistant, translucent, and transparent, used in line bending, car light casings, and bathtubs.
• Low-density polyethylene (LDPE) has low rigidity, used in plastic wrapping and disposable shopping bags.
• Polyethylene terephthalate (PET) has high tensile strength, used in detergent and shampoo bottles.
• High-density polyethylene (HDPE) is waterproof, translucent, and transparent, used in plastic bottles, toys, and buckets; suitable for blow molding.
• Polypropylene (PP) has good fatigue resistance, used in flimsy ring binders.
• Polyvinyl Chloride (PVC) is flexible, used in hose pipes, book protectors, and food-grade vacuum form trays.
• Unplasticized Polyvinyl Chloride (uPVC) is opaque, has good weathering resistance and rigidity, used in pipes, window frames, and doors.
• Acrylonitrile Butadiene Styrene (ABS) is rigid, used in rigid suitcases and casings.

1.3 Polymers (Thermosetting Plastics)

• Thermosetting plastics form rigid cross-links under heat and cannot be reshaped.
• Urea formaldehyde is hard, heat resistant, a good electrical insulator, and brittle, used in domestic electrical equipment like plug sockets.
• Epoxy resin is rigid, clear, hard, and tough, used in casting and encapsulation.
• Polyester resin is rigid, heat resistant, and brittle, used in the lay-up process for glass-reinforced plastic (GRP).

1.3 Polymers (Elastomers)

• Elastomers can be deformed under pressure at room temperature and return to their original shape.
• Natural rubber has high tensile strength, low elongation, good hardness, electrical insulator, and good cold resistance, used in tires and balloons.
• Neoprene is tough, has good oil and chemical resistance, and abrasion resistance, used in wetsuits.

1.4 Composites

• Composite materials comprise two or more different materials that are not chemically bonded.
• Carbon Fiber Reinforced Plastic (CFRP) is a combination of carbon fibers and polyester resin; lightweight, corrosion resistant, tough, has low thermal expansion, and is stiff; used in sports equipment and racing car bodies.
• Glass Reinforced Plastic (GRP) is a combination of glass fibers and polyester resin; lightweight, tough, is an electrical insulator, and is transparent to radio waves; used in boat hulls and water tanks.
• Both CFRP and GRP are made using lay-up lamination
• Medium Density Fiberboard (MDF) has a smooth surface, is dimensionally stable, easily shaped, and takes paint well.
• Hardboard has a smooth surface, is tough, and used in wardrobe backing.
• Chipboard is strong in all directions but unattractive, used in flat-pack furniture with veneers.
• Plywood has an odd number of layers, with the top and bottom grain direction parallel, making it very strong and stable.
• Manufactured boards are susceptible to moisture and water damage unless properly finished.
• Tungsten carbide is used in drill bits for its exceptional hardness.

1.5 Papers and Boards (Drawing Papers)

• Layout paper is thin and translucent, used for transposing images in sketch pads.
• Tracing paper is slightly thicker than layout paper, used for copying images when drawing.
• Copier paper is an inexpensive general-purpose paper that can be colored, used for generic office printing.
• Cartridge paper is off-white with a slight texture, useful for sketching.
• All four papers have a smooth surface finish suitable for most drawing media.

1.5 Papers and Boards (Boards)

• Mounting board is made from compressed cotton fibers, used for picture mounting or modeling.
• Corrugated cardboard has outer layers of carton board with a corrugated middle layer, used in protective packaging.
• Foam board has a foam middle core with two outer layers of card, used in presentation boards.
• Folding box board has multiple layers of pulp with a pigmented top layer for good printability, can be embossed, used in packaging.
• Foil lined board is a board with foil applied to provide water resistance, used in drinks packaging and milk cartons.

1.5 Papers and Boards (Commercial Printing Papers)

• Bond paper is uncoated, high-quality, bright, durable, and good for color holding, used in general printing.
• Coated paper is used in magazines and glossy materials, good for sharp, complex images with a smooth and glossy finish.

1.6 Textiles (Natural Fibers)

• Cotton comes from the cotton plant, has high absorbency, dies easily, has high breathability, resists static, and is used for towels, bedding, and clothing.
• Linen is made from flax fibers, durable, lightweight, crisper and stiffer than cotton, has high wrinkle resistance, and is used in suits, elegant clothing, and home furnishings.
• Wool is made from the fleece of sheep, has high warmth and low durability, and is inherently flame resistant, making it suitable for environments where fire safety is a concern.
• All three natural fibers have high breathability, high absorbency, and are biodegradable.

1.6 Textiles (Man-Made Fibers)

• Nylon has low absorbency, high durability, high elasticity, and high tear resistance, used as an industry fabric due to its strength.
• Polypropylene is used in sportswear because it is quick drying and lightweight.
• Polyester is incredibly durable, retains shape, and is crease resistant, used in trousers and shirts.

1.6 Textiles (Textile Treatments)

• Proban is a fire retardancy chemical used to delay the spread of fire.
• PTFE forms a thin protective layer on the fabric surface, preventing stains from penetrating fibers
• Coating fibers with a chemical reduces absorbency, used in outdoor products for water resistance.

1.7 Smart and Modern Materials

• An external stimulus is any signal from the environment that triggers a response in a smart material.
• Thermoceramics are a mixture of metallic powder and ceramic powder compacted into a mold and formed by heating up the mold and applying pressure.
• A change in temperature causes a change in thermal properties, which allows for efficient temperature regulation.
• Thermoceramics, including tungsten carbide, are incredibly hard and stable at high temperatures, used in automotive parts, drill bit tips, and metal cutting tooling.
• Shape memory alloys return to their original shape due to an external stimulus.
• A nitinol wire in braces returns to its original shape due to the warm temperature in the mouth.
• Liquid Crystal Displays (LCDs): An electric voltage causes liquid crystals to change from light to dark, used in screens and calculator displays.
• Reactive glass changes tint due to an external stimulus, used in windows.
• Photochromic pigment changes color due to a change in light intensity, used in welding goggles.
• Quantum Tunneling Composites (QTCs): A change in pressure or physical strain causes a change in electrical conductivity, used in touchscreen technology and pressure sensors.
• Thermochromic pigment changes color due to a change in temperature, used in color-changing mugs to indicate temperature.

2. Properties of Materials

• Electrical conductivity is the flow of electric current through a material with little resistance; gold, copper, and brass have high electrical conductivity.
• Electrical insulators resist electric current; rubber, PVC, and timbers are examples of electrical insulators.
• Thermal conductivity allows the transfer of heat energy quickly throughout a material; metals are examples of thermal conductors.
• Thermal insulators resist the transfer of heat energy; styrofoam is an example of a thermal insulator.
• Elasticity is the ability to be deformed and then return to its original shape once the force is removed; rubber is an example.
• Plasticity is the ability to be permanently deformed and retain the new shape; clay is an example.
• Malleability is the ability to withstand compression without cracking; aluminum is an example.
• Ductility is the ability to be drawn out under tension, lacking to wires; copper is an example.
• Hardness is the ability to withstand scratches; diamond is a hard material.
• Toughness is the ability to absorb impact forces; steel is an example.
• Durability is the ability to withstand wear and tear; stainless steel is a durable material.
• Biodegradability is the ability to naturally decompose; paper is an example.

2. Properties of Materials (Strength)

• Tension is a pulling force.
• Compression is a pushing force.
• Shear is a sliding force.
• Torsion is a twisting force.
• Bending involves tension and compression.

2. Properties of Materials

• Woods expand and contract with changes in humidity, and are seasoned by using air or kill dried to remove excess moisture before it is used.
• Wood is strong in the direction of the grain and weaker across the grain.
• Metals are naturally occurring materials from the ground in the form of ore, and are easily recycled due to having a low melting point.
• Polymers are made using crude oil, a finite resource, and are self-finishing, requiring no additional finishing process.
• Composites have enhanced properties because they mix properties from two or more different materials.
• Carbon fiber reinforced plastic and glass reinforced plastic can be easily molded into 3D forms.
• Papers and boards can be scored, folded, and cut with basic tools.
• Bleaches are added to paper to make it whiter.
• Man-made fibers in textiles do not absorb liquids.
• Modern materials are developed through the invention of new or improved processes.

3.1-3.3 Printing Processes (Offset Lithography)

• Uses a blanket cylinder
• Can simultaneously print multiple colors
• Blanket cylinder leads to registration issues
• Used for large-scale printing (newspapers, magazines)
• Plate cylinder, impression cylinder, ink rollers, & blanket cylinder.

3.1-3.3 Printing Processes (Flexography)

• Uses flexible relief plates (rubber or polymer)
• Suitable for high-speed printing and different substrate sizes
• Not ideal for rigid or uneven surfaces
• Limited resolution
• Expensive printing plates last for millions of prints
• Used in packaging and label printing industries

3.1-3.3 Printing Processes (Gravure)

• Most expensive process
• Uses engraved cylinders
• Allows for thick ink deposits, opaque prints
• High cost and uses solvent-based inks
• Not economic for small print runs
• Used in high-quality magazine printing and packaging

3.1-3.3 Printing Processes (Screen Printing)

• Ink pressed through mesh screen using a stencil
• Allows for thick ink deposits
• Each color requires a separate screen
• Increases production time and cost
• Often used on t-shirts and keyboards

3.1-3.3 Printing Processes (Quality Assurance)

• Registration marks lines up colors
• Color blocks

3.1-3.3 Casting (Sand Casting)

• Uses a Sand and binding material
• Labor-intensive
• Does not give a high-quality surface finish
• Used to create large and complex parts (vices, post boxes)
• Two parts (cope and drag)

3.1-3.3 Casting (Investment Casting)

• Wax pattern coated with a ceramic shell melted to create gap
• High dimensional accuracy
• Allows intricate details with a smoother surface finish
• Used for small parts like jewelry
• Very expensive and time-consuming

3.1-3.3 Casting (Pressure & Gravity Die Casting)

• Pressure die casting stores molten metal in a chamber, forced into the die with pressure
  • Fast
  • used for mass production
• Gravity die-casting
  • reuses metal mold
  • relies on gravity to fill mold.
  • Good dimensionally accurate, high surface finish.
  • high volume production
  • not suitable for complex shapes.

3.1-3.3 Casting (Plaster of Paris & Resin Casting)

• Plaster of Paris
  • Fast process
  • Used for metals with lower melting points (zinc, magnesium)
• Resin Casting
  • Polymers
  • Simple process
  • Low cost

3.1-3.3 Heat Treatment (Annealing, Case Hardening)

• Annealing: Heat and cool hardened metal relieves internal stresses and improves ductility
• Case hardening: Provides a harder outer surface, diffusion of carbon atoms and quenching metal heated and cooled quickly.

3.1-3.3 Heat Treatment (Hardening, Tempering, Normalizing)

• Hardening: Heat the metal and cool rapidly in water or oil makes metal stronger but more brutal
• Tempering done after hardening: reduce brittleness and increases toughness, reduces the brutalness and increases toughness and the metal is heated to below the critical point and then slowly a cooled
• Normalizing gives low carbon steel a uniform fine green structure and increases ductility material is heated and then quickly quickly quenched

3.1-3.3 Alloying

• Alloy Metal made of two or more other metals or combining two or more elements gives enhanced properties over original
  • Produced in the furnace through casting.

3.1-3.3 Machining Processes (Milling, Routing, Drilling)

• Milling and routing: make holes or channels in Wood
• Drilling rotating drill bit drills into static metal
• Stamping sheet metal: cut using a stamping procedure

3.1-3.3 Machining Processes (Pressing, Turning)

• Pressing Sheet metal: placed in between two dieses 3D forms
• Turning uses lathe machine
• Used to make spindles

3.1-3.3 Lamination and Lamination Processes

• Layup lamination, glass-reinforced plastic and carbon fiber, Mold is prepared and a release agent is sprayed Mats are placed with polyester resin in between; roller used to remove air bubbles & the resin is cured.
• Wood lamination Vene has adhesive applied then bent over a former held with pressure High strength & High stability; size not limited.

3.1-3.3 Molding Processes

• Vacuum Forming, thermoplastic sheet up to 6 mm thick is heated and lowered onto the mold Requires Draft angle air holes and rounded corners
• Injection Molding Used for electrical product casings; quick 3D shapes thermoplastic granules are placed into the hopper archmedian screw feeds to polymer through the barrel

3.1-3.3 Molding Processes (Blow & Rotational Molding)

• Blow molding makes thin wall components, thermoplastic tube becomes flexible then placed inside a split mold expansion is by air
• Rotational whiches reduces material cost, the ACT Parts is Hollow filled mold with plastic granules heated and rotated

3.1-3.3 Extrusion

• This is similar to injection modding but polymer is forced through the die no mold use to make continuous Lens

3.1-3.3 Marking out

• Marking Techniques Marking cutting gauges parallel lines mark hole Scieber shows fold Accurate starts Accuracy close to required value
• Callipers Odd leg/internal/external/micrometer

3.1-3.3 Making Squares

Engineers sets:

• set Square,Tri Square Engineer Squares is used on Woods/ Metres Square Dividers can measure distance between parts Denso simmers used to determine optical density for printed inks. Jigs tools vice versa

3.1-3.3 Drawing and Reporting.

Drawing Methods

• Isometric/Perspective Triangulation: packages model Ortho-graphic: Third angle diagram. front end and side used in manufacturing..accurate. Net: 2D Technical Report: A Design Report Design Report: A Record

3.4-3.5 Adhesives

Contact adheres sheet materials or different materials instant addition with good contact Acrylic Cement fuses polymers Epoxy 2 part system PVA: water-based use wood Polystyrene cement: fuse Super fast acting can bind skin Glue guns: Model manufacture not too strong

3.4-3.5 Fasteners

Screw twists to join Nuts bolts and washers: connect with threads and spread loan Rivets fastens metals sheet Press fits relies interference and connection. Counter screw : Tapered shape and depression

3.4-3.5 Heat Processes

Welding fusion while Brazing materials are joined (not fused) OXY and acetylene: uses filler MiG: metals thin Argan shield

3.4-3.5 Welding

Protective Visor, Gaunlets, apron, curtain Preparations metal must be clean

3.4-3.5 Wood Joints

• Finger, housing, joint, Half-lap Joint dowel joints Mt Tenon
• Knockdown fittings assembly disassemble require min tools skills ex corner bowel and hinges.

3.4-3.5 Finishing Techniques

Wood varnish/ Oil Surface Sealants metal polymer based barrier Powder Coating and aluminum- coating and charging Carbonization Steel uses zinc cathodic protect metal ship underwater The thickness should be negligible. The functionality should be good . The electro-coating should also be beneficial