GCSE DT

Annotation

Brief notes that are applied to a design sheet to inform a designer or other of important factors

Annotation Factors

Materials, Properties, Design features, Evaluation points, Notes

Prototyping Benefits

Idea of future appearance, Apparent scale, Spot errors, Iterate

Datums

Datums allow reference points for all measurements to be taken from, improving and maintaining accuracy

Health and Safety

Dress appropriate - according to the PPE, Use appropriate safety equipment, Be sensible

Types of Wood

hardwood, softwood, manufactured board

Cost of Timbers

Longer maturity age = higher cost. Hardwoods take longer to mature (100-130 years vs 10-30). Trees in more humid environment grow fast vs cold environment.

Grain Structures

Hardwood grain structure is tightly packed rings while softwoods have gaps due to fast maturity

Woods converted to be useable

Felled, then transported and converted to planks, Then seasoned which is reducing moisture and finally cut to stock sizes

Manufactured Boards Explained

Don't come from natural trees. Combined woods to have new properties, different strength and larger sizes.

Softwood Examples

Pine, Cedar, Redwood and Spruce.

Hardwood Examples

Oak, Teak, Beech

Manufactured Examples

MDF, Plywood and Chipboard

Pine

Cabinetry, furniture, panelling, window framing, roofing and floors. Strong, durable and high elasticity

Cedar

Outdoor furniture, decking. Rot and insect resistant.

Redwood

Veneer, construction beams, exterior furniture. Strong, resists warping and splitting, and is durable

Spruce

Sounding boards in pianos and violins, Guitars, construction, boats and planes. Very strong, high elasticity, light-weight, doesn't shrink when dried.

Oak

Furniture, joinery, flooring, decking, panelling and veneers. Durable and long-lasting.

Beech

Staircases, treads, moulding, timber frames and tool handles. Dense, tough, strong while high eleasticity

Teak

Outdoor furniture, boat decks, indoor flooring, countertops and veneers. Naturally produces oil, high tensile strength, tight grain, weather resistant.

MDF

Furniture, cabinets, shelves, speaker bones, doors, frames, theatre set. Cheap, smooth finish, consistent throughout.

Plywood

Interior walls, construction, furniture and cabinets. Stability, high impact resistance, surface dimensional stability, high strength:weight

Chipboard

Kitchen worktops, cabinets, flooring, insulation. Great sound absorption, heat insulation, good surface for laminate or veneer

Wood finishes advantages

Protects against insects, fungi, weathering. Allows enhancement of wood.

Wood finish choice depends on:

Oil content, odours, level of protection required, appearance you want.

Indoor Wood Finishes

Veneer, Coloured wax, paint.

Ferrous Metals

Metals that contain iron such as stainless steel. Strong and cheap but weak to corrosion.

Non-ferrous Metals

Metals that don't contain iron such as copper. More resistant to corrosion and often better conductors. More expensive.

Alloys

A mixture of two or more substances (at least on metal, usually more) which retain metallic properties. Can have improved/different properties, e.g. Brass.

Advantages of stock forms

Easier transport and handling, cheaper, used by designers

Ferrous example 1

Stainless steel

Used in cars, fridges, scalpels

Very durable, corrosion resistant, easy to manipulate.

Ferrous Example 2

Wrought Iron

Used in rivets, steam pipes

Malleable, can be heated and shaped, soft, magnetic.

Non-ferrous Example 1

Aluminium. Aeroplane parts, foil. Non-magnetic, can be cast, thermally conductive.

Non-ferrous Example 2

Copper. Cables, water pipes. Corrosion resistant, good conductor, non-magnetic

Alloy Example 1

Bronze. Sculptures, coins, furniture trims. Conductive, high melting point, corrosion resistant.

Alloy Example 2

Brass. Instruments, gears, cloves in water pipes. Good conductor, very malleable, corrosion resistant.

Metal finishes offer:

Protection against corrosion and weathering, allows properties to be altered and allows enhancement of appearance.

4 types are:

Powder Coating, Galvanising, Anodising and Chrome plating

Powder Coating

Powder is charged and sticks through electrostatic attraction to the metal. Powder is melted on.

High corrosion resistance, durable.

Colour fades, thin coats are hard, can deteriorate from UV.

Examples include Household appliances, cars, Bike frames.

Galvanising

Hot dip - metal is dipped into melted zinc.

Electro - applied using charge and attraction.

Can have a very thin layer, corrosion resistant and low maintenance.

More expensive than others and limited colours.

Examples include Bridges and construction beams.

Anodising

Metal is cleaned and kept in acid with electrodes and current and then oxidation occurs.

Corrosion resistant, no risk of fading, low initial cost.

Can only be used for specific metals.

Examples include fridges and window frames.

Chrome Plating

Thin layer of chromium applied through electroplating.

Increases hardness and durability, prevents corrosion, makes it easier to clean.

Chrome could crack, bad for environment, bubbles produced.

Examples include car parts, tools and kitchen utensils.

Examples of CAD - computer aided design

3D design packages - Onshape. 2D design packages - Photoshop. Simulation packages - PICAXE, Arduino.

Examples of CAM - computer aided manufacture (CNC - computer numerical controlled)

Milling machines, Routers, Lathes, Cutting, Rapid prototyping - Sintering, multi jet, Inkjet, FDM, SDL, Sterelythography.

Advantages of CAD

Saves time & money, determine costs and test other variables, easy to manipulate, review options before final commitments and better flow of design communication.

Disadvantages of CAD

Less people employed, high initial costs, takes a long time to replicate paper sketches into CAD.

What is a fibre

The raw materials that are refined to make fabrics

3 types of fibre

Natural - plants & animals.

Synthetic - man made sources like coal

Blended/mixed - yarns of diff fibres mixed

3 types of woven fabrics

Plain, twirl, satin

Non-woven Farbics

Bonded - Pressure + heat adhesives

Felted - Heat, moisture and friction

Knitten

Made up of inter-locking loops

Most common used = warp (vertical) & weft

Fibre used is synthetic

Jig

A manufacturing tool which allows multiple of the same item to be made accurately

Jig vs Template

Jig clamps, Template doesn’t

When choosing drill bit

Size of hole, Material being drilled, accuracy needed

Drill bit materials

HST - any usage, cheap

Cobalt - very strong, for stainless steel

Carbide tipped - VERY strong, masonry, tiles

Solid carbide - VERY STRONG, expensive, same prev

Tungsten Carbide - EVEN STRONGER, for tough materials

Plastics

Most from oil, some from plants

Called polymers cuz come from oil

Types are thermosetting and thermoforming

Thermoforming

Formed with long messy chains

Do not resist heat

Easily formed into shapes with heat

Recyclable

Thermosetting

Rigid cross links

Resists heat & fire

Chemical change from heat & mould

NOT RECYCLABLE

ABS

High impact strength, light, tough, no stretch

Phone cases, toys, safety helmets

MOBIUS 7

PET

Light, strong, tough

See-through bottles, clothe fibres

MOBIUS 1

HDPE

Stiff, strong, light

Washing up bowls, baskets, water pipes

MOBIUS 2

PVC

Brittle, cheap, durable, defeated by UV

Blister packs, window frames

MOBIUS 3

LDPE

Semi-rigid, translucent, very tough, weather resist

Plastic bags, dispensing bottles

MOBIUS 4

PP

Tough, flexible, many colours, bendy, comfy

Plastic chairs, plastic folders

MOBIUS 5

PS

Light, rigid, insulates, low impact strength

Packaging, cups, plates, containers

MORBIUS 6

Acrylic (PMMA)

Hard, stiff, high shine, weather resistant, brittle

Visors, machine guards, baths, shower trays

MORBIUS 7

UF - Urea Formaldehyde

Hard, brittle, insulator

Plug sockets, Cupboard Handles

Thermosetting

MF - Melamine Formaldehyde

Strong, scratch resistant

Worktops, flooring, plates, bowls, mugs

Thermosetting

Silicone

Insulator, hydrophobic, water tight seals

Sealants, adhesives, lubes, utensils, moulds

Thermosetting

Layout Paper

Thin and Translucent

60 gsm

Design work e.g. drawing

Coppier Paper

Matt coating, wide range of colours

80 gsm

General use, printing, photocopying, e.t.c.

Sugar Paper

Slightly rough, wide range of colours

100 - 120 gsm

Projects, Crafts, Display work

Cartridge Paper

High quality & textured, white

130 gsm

Sketching w/ pencils, crayons e.t.c.

Tracing Paper

Very thin

40 gsm

Architecture, image tracing

Bleed-proof Paper

Specially treated surface for no bleed. HD colours

70 gsm

Used with markers, felt tips

Card

Many colours, sizes & finishes, foldable

180-300 gsm

Greeting cards, paperback books e.t.c.

Cardboard

Many sizes & finishes, cheap, foldable

300 gsm

Packaging

Corrugated Card

Strong, has flutes, stiff

3mm +

Packaging delicate items, pizza boxes

Board Sheets (Mounting board)

Rigid, smooth finish

1.4mm +

Architectural modelling, framing

Styrofoam

Many sizes, blue, bunch of small cells

3D modelling, insulation, organic 3D forms

Foam Board

Polystyrene sandwiched between paper.

Smooth finish, range of colours, sizes & thickness

5mm+

Modelling, point of sale displays

Types of CAM (computer aided manufacture)

Milling machines

Routers

Lathes

Rapid prototyping - sintering, 3D printing, multijet

Examples of 3D printing are Injection, FDM, stereolythogrpahy and SDL

System diagrams definition + uses

A schematic that shows the different stages of a system

Allows you to learn all components needed

Helps understand the task as it simplifies it

Allows you to trace back to a fault

Saves money

System diagrams, what they consist of + different types

They consist of input(s) first, then the process and finally output(s)

The two types are open and closed loop, closed has feedback while open doesn’t

Physical (analogue) quantities

Sound, Movement, Light, Heat, mass, density, orientation

Input + output transducers

USE BOOK PLEASE DON’T LOSE THAT SHIT CUZ OTHERWISE YOU’RE COOKED AND I CANNOT BE BOTHERED TO TYPE THEM ALL ON HERE OK?

Transistors

They can be used as an amplifier or a switch

The entrance is called the base, the top exit is the collector and the bottom exit is the emitter

Base, collect, emitter

Base controls direction of current flow based on voltage

Current flows through the collector if V < 0.7

Current flows through the emitter if V > 0.7

Two parts of a switch

Pole = input, Throw = output

potential divider equation

Vout = Vin x R2 / R1 + R2

Types of microcontroller

PROM - programmable read only memory

EPROM - electronically PROM

EEPROM - electronically erasable PROM

EAPROM - electronically alterable PROM

What is a mechanism