Materials and Manufacturing Booklet

Higher and Intermediate 2

Product Design

Ferrous metals Ferrous metals are metals that consist mostly of iron and small amounts of other elements. Ferrous metals are prone to rusting if exposed to moisture. Ferrous metals can also be picked up by a magnet. The rusting and magnetic properties in ferrous metals are both down due to the iron. Typical ferrous metals include mild steel, cast iron and steel.

Metal Alloys Alloys are substances that contain two or more different metals and occasionally other elements. The metals are carefully chosen and mixed to achieve specific properties these include reducing the melting point making the alloy light weight, etc.

Non-ferrous metals Non-ferrous metals are metals that do not have any iron in them at all. This means that Non-ferrous metals are not attracted to a magnet and they also do not rust in the same way when exposed to moisture. Typical Non-ferrous metals include copper, aluminium (coke cans), tin and zinc.

Metal

Metal Type

Use

Melting Point

Example Product

Processing

Mild steel - A ductile and malleable metal. Mild steel will rust quickly it is in frequent contact with water.

Used as Nuts and bolts, Building girders, car, bodies, gates, etc.

1600°C •Piercing and Blanking •Extrusion •Press Forming •Drop Forging

Cast iron - Is very strong when it is in compression and is also very brittle.

Used as car Brake discs, car cylinders, metalwork vices, manhole covers, machinery bases e.g.: The pillar drill.

1200°C •Sand Casting •Drop Forging

High carbon steel / Tool steel - Is a very strong and very hard, resistant to abrasion.

Used for hand tools such as screwdrivers, hammers, chisels, saws, spring and garden tools.

1800°C •Drop forging •Press forming

Stainless steel - is very resistant to ware and water corrosion and rust.

Used for kitchen sinks, cutlery, teapots, cookware and surgical instruments.

1400°C •Drop forging •Press Forming •Piercing and Blanking

High speed steel - is a metal containing a high content of tungsten, chromium and vanadium. However it is very brittle but is also very resistant to wear.

Used for drill bits, lathe tools, milling cutters on milling machines. It is used where high speeds and high temperatures are created.

1400°C •Drop forging

Metals – Ferrous and Alloys

Metal Type

Use

Melting Point

Example Product

Processing

Aluminium - tends to be light in colour although it can be polished to a mirror like appearance. It is very light in weight.

Used for saucepans. cooking foil, window frames, ladders, expensive bicycles.

660°C •Piercing and blanking •Sand Casting •Die Casting •Press forming

Copper – is a ductile and malleable metal. It is often red / brown in colour. It is a very good conductor of heat and electricity.

Used for plumbing, electric components, cookware and roof coverings.

1084°C •Piercing and blanking •Press forming •Drop forging •Extrusion •Die Casting

Zinc – is very resistant to corrosion from moisture. However zinc is a very weak material.

Used as a coating on screws, steel buckets, American cents. It is also used to galvanise steel.

419°C •Die casting

Brass – Is often cast and machined then plated. It is yellow in colour

It is used for decorative metal work such as door handles, candle sticks, musical instruments, ornaments.

900–940 °C depending on composition

•Press forming •Die casting •Piercing and Blanking •Extrusion

Metals – Non - Ferrous and Alloys

Process

Diagram Materials Identifying Features Uses

Sand Casting Most frequently used casting process. Quality of the cast depends on the quality of the pattern.

Iron, aluminium and non ferrous alloys, precious metals

Surface texture can be poor, draft angles and fillets, round corners. You might be able to see where the runners and risers have been removed.

Engine parts, tools, jewellery, etc

Die Casting Where large quantities of quality castings are required. High operating costs, therefore used in mass production.

Low melting alloys, lead, zinc, aluminium and brass alloys

Section hair lines, ejector pin marks, flash caused by leaks, sprue and runner marks.

Toys e.g. Cars, aeroplanes, sharpeners, tools

Press Forming Involves squeezing sheet metal between two matched moulds. Expensive and time consuming to make moulds.

Sheet metal: various steels, aluminium alloy, brass, copper

Sharp bends, deep draws,

Everyday products, pans, kettles, stainless steel sinks, trays.

Piercing and blanking Stamping out of shapes. Stamping – the shape of the product. Piercing - making a shaped hole in the product.

Most types of metal can be pierced and blanked in sheet or strip form.

May become deformed or fracture.

Washers, flat plates e.g. Blades for a spokeshave, decorative work, e.g. Dog tags

Drop Forging Impression drop forging using high pressure on hot metal billets to form a product. Accurate repetition of shapes.

Most metals in alloy form. Alloy steels and copper are most common.

Flashing or flash removal around the edges. Further finishing may have been done to remove this however.

Increases the strength of the metal, therefore can be used for tools, spanners, hammer heads and domestic cutlery.

Metal Processing

Plastics

Thermosetting plastics Thermosetting plastics can only be heated and shaped once. If re-heated they cannot soften as polymer chains are interlinked. Separate polymers are joined in order to form a huge polymer. The main thermosetting plastics are epoxy resin, melamine formaldehyde, polyester resin and urea formaldehyde.

Thermosetting Plastics

Properties Uses Example Product Processes

Epoxy resin Good electrical insulator, hard, brittle unless reinforced, resists chemicals well.

adhesives, bonding of other materials. Used for printed circuit boards

•Compression Moulding

Melamine formaldehyde (MF)

Stiff, hard, strong, resists some chemicals and stains.

Used for Laminating work surfaces, electrical insulation, tableware.

•Laminating

Polyester resin Stiff, hard, brittle unless laminated, good electrical insulator, resists chemicals well.

bonding of other materials, car bodies, boats.

Urea formaldehyde

Stiff, hard, strong, brittle, good electrical insulator.

Used for electrical fittings, handles and control knobs, adhesives.

•Compression Moulding •Rotational Moulding

Phenol Formaldehyde (Bakelite)

A colourless polymer - coloured with artificial pigments to produce a wide range of different colours.

Used for dark coloured electrical fittings and parts for domestic appliances, bottle tops, kettle handles, saucepan handles.

Compression Moulding

Thermoplastics Thermoplastics can be heated and shaped many times. Thermoplastics will soften when it is heated and can be shaped when hot. The plastic will harden when cooled, but can be reshaped because their is no links between the polymer chains. Some common thermoplastics are ABS (acrylonitrile butadienestyrene), Nylon (polyamide), acrylic (polymethyl methacrylate), uPVC (polyvinyl chloride), polystyrene, polypropylene and cellulose acetate.

Thermoplastic Properties Uses Example Product

Processes

Acrylic Stiff, hard but scratches easily, durable, brittle in small sections, good electrical insulator, machines and polishes well.

Used for signs, covers of storage boxes, aircraft canopies and windows, covers for car lights, wash basins and baths.

•Vacuum forming

High impact polystyrene

Light but strong plastic. Widely available in sheet softens at about 95 degrees.

Used for vacuum forming. Common for school projects which include products outer casings or packaging.

•Vacuum forming •Extrusion

Polypropylene Light, hard but can scratch easily, tough, good resistance to chemicals, resists work fatigue.

Used for medical equipment, containers - especially with built-in hinges, 'plastic' seats, string, rope, kitchen equipment.

•Injection Moulding •Extrusion •Rotational Moulding •Vacuum Forming •Blow Moulding

Thermoplastic Properties Uses Example Product

Processes

Polythene: - low density (LDPE)

Tough, good resistance to chemicals, flexible, fairly soft, good electrical insulator.

Used for packaging, especially bottles, toys, packaging film and bags.

•Blow Moulding •Rotational Moulding

Polythene: - high density (HDPE)

Hard, stiff, able to be sterilised.

Used for 'plastic' bottles, tubing, household equipment and milk crates.

•Vacuum Forming •Injection Moulding •Blow Moulding •Extrusion

PVC Stiff hard wearing. Plasticiser can be added to create a softer more rubbery material.

Used for air and water pipes, shoe soles, blister packaging

•Vacuum Forming •Extrusion •Rotational Moulding

Acrylonitrile butadiene styrene (ABS)

Strong, light, durable and scratch and chemical resistant. Good surface finish.

Packaging, lids and containers.

Injection Moulding Vacuum forming

Thermoplastics continued

Plastic Processing

Process Diagram Materials Identifying Features

Uses

Injection Moulding Large quantities of components can be manufactured quickly. Thermoplastics granules are heated and softened and forced into a mould. When cool the mould is opened a component exactly the shape of the mould is taken out.

Thermo Plastics Polypropylene, ABS, etc

Sprue Marks, draw angles, mould split lines, ejection pin marks, injection marks. Webs for strength.

Used in mass production of plastic goods. Therefore large quantities of a product must be sold to recover costs. Golf Tees, spoons, wash basins, buckets and product casings.

Compression Moulding Process most used for shaping Thermosetting plastics. The process requires plastic to be placed into a mould cavity where it is heated and plasticised. It is then compressed into shape by a heated punch.

Phenol- Formaldehyde and urea formaldehyde, epoxy resin (thermo- Setting Plastics)

Walls of uniform thickness usually 3-6mm. Draft if 1° minimum required. Flashes on edges. Quality finish on female side of surface.

Good electrical insulators. Used in products where there is a risk of increased temps. Camera cases, electrical wall sockets, handles, and light switches.

Extrusion Used for products with long uniform sections. A variety of metal and thermoplastics are suitable for this process.

Polythene, PVC and polypropylene. Suitable metals include lead, copper, brass, bronze, aluminium alloy and steel.

Smooth walled long sections with uniform thickness. Line textures may be evident, esp’ on metal.

Curtain rails, drainpipes, electrical cable sheathing, hose pipes.

Plastic Processing 2

Process Diagram Materials Identifying Features

Uses

Vacuum Forming •Thin plastic sheet is used, in a variety of colours. Cheap to produce the moulds and process complete in a few minutes. •Air is removed from underneath a heated , soft and flexible sheet of thermoplastic. •Sides should be tapered (draft) to allow the mould to be removed and corners rounded.

Thermo-plastics: polythene, PVC, high density polystyrene, ABS and acrylic

Any patterns or textures are transferred from the mould. Venting holes cause ‘pips’ on the surface. Tapers are pronounced and there can be thinning of the plastic.

Dishes, trays, chocolate box inserts, toys, lighting panels.

Blow Moulding Softened thermoplastic is forced on to the mould surface using compressed air. Fast process and very little waste.

Thermo-plastics

Mould separation lines, Threaded necks are easily produced .

Mass production of bottles and liquid containers.

Rotational Moulding Used to produce ‘closed and seem free’ components made from plastic polymers. No external pressure is used in the process. The mould is rotated on several axes.

Polyvinyl chloride (PVC) , Polypropyl-ene, low density polythene and nylon

Excellent surface detail. Effects such as wood grain can be produced. Mouldings should be designed to avoid sharp sections and thin or weak areas

Large tanks, balls, hollow plastic toys, buoys.

Wood

Processes

Joint/Fixings Use Material

Dowel Cheap furniture, e.g. Flat packed furniture. Often used with other fittings. Used in mass production

Plywood and other manufactured boards, Red Pine

Housing

Shelving Red Pine (softwoods), some hardwoods, e.g. Mahogany

Rebate Corner joint used in cabinets and tables. Can be glued, pinned or screwed in position

Softwoods, some hardwoods for e.g. Mahogany

Dovetail Expensive furniture. Joint used in the manufacture of the carcase of cabinets of drawers. Can be used in batch production (smaller, more expensive runs)

More expensive materials such as mahogany, oak etc.

Mortise and Tenon

Construction of tables etc Red Pine (and other softwoods), hardwoods such as mahogany and oak.

Screws, and knock down fittings

Flat packed furniture. Used in mass production

Plywood, laminates (manufactured board e.g. Chipboard underneath)

Softwoods

Softwood Properties Use Example

RedPine Quite strong, Lots of knots, durable when preserved. cheap

Used for general woodwork, cupboards, shelves, roofs.

Scots pine straight-grained softwood but knotty. Light in colour. Fairly strong but easy to work with. Cheap and readily available.

Used for DIY and cheap quality furniture. Mainly used for constructional work and simple joinery.

Yellow cedar A pale yellow-coloured softwood with a fine even texture. Light in weight but stiff and stable.

Used for furniture, boat building, veneers, and model making.

Hardwoods

Beech A straight-grained hardwood with a fine texture. Light in colour. Very hard so is ideal to be used where it is being bashed around and used often. Beech is also very easy to work with.

Used for furniture, toys, tool handles. Can be steam bent

Oak A very strong wood which is light in colour. Open grain. Hard to work with. When treated it looks very classy and elegant

Used for high class furniture, boats, beams used in buildings, veneers.

Mahogany An easy to work wood which is reddish brown in colour. This wood is very expensive

Used for expensive indoor furniture, shop fittings, bars, veneers.

Balsa A pale white to gray. It has a distinct velvety feel. It has exceptional strength to weight properties. It is the lightest and softest wood on the market.

Used for light work such as model making and model airplane construction.

Manufactured Boards

MDF Smooth, even surface. Easily machined and painted or stained. Also available in water and fire resistant forms.

Used mainly for furniture and interior panelling due to its easy machining qualities. Often veneered or painted.

Plywood A very strong board which is constructed of layers of veneer or piles which are glued at 90 degrees to each other. Interior and exterior grades are available.

Used for strong structural panelling board used in building construction. Furniture making. Some grades used for boat building and exterior work.

Chipboard Made from chips of wood glued together. Usually veneered or covered in plastic laminate

Used for kitchen and bedroom furniture usually veneered or covered with a plastic laminated. Shelving and general DIY work

Blockboard Similar to plywood but the central layer is made from strips of timber. Good for shelves and worktops.

Used where heavier structures are needed. Common for shelving and worktops.

Hardboard A very cheap particle board which sometimes has a laminated plastic surface. A manufactured board.

Used for furniture backs, covering curved structures, door panels.

Process Explanation Use Example

Wood Turning

Woodturning is a form of woodworking that is used to form an object on a lathe. There are 2 types: spindle turning and face plate turning

Pillars, bowls, decorative candle sticks, pools cues. Can be automated and template based to produce identical pieces quickly