DT Notes PDF

1.1 New and Emerging Technologies Sustainability, People, Culture, Society, Environment, Industry, Enterprise Sustainability: Sustainable → Not causing permanent damage to the environment and not using up finite resources. All products have a Carbon Footprint Carbon Footprint→ Amount of greenhouse...

1.1 New and Emerging Technologies Sustainability, People, Culture, Society, Environment, Industry, Enterprise Sustainability: Sustainable → Not causing permanent damage to the environment and not using up finite resources. All products have a Carbon Footprint Carbon Footprint→ Amount of greenhouse gases (CO2 + methane) released into the atmosphere by making, using, recycling and disposing of something at the end of its lifetime. - Transportation of new products causes release of CO2 as well. - Carbon footprint can include emission during manufacture and other processes involving reuse and recycling - More energy needed for processes, bigger the carbon footprint - The bigger the carbon footprint, the larger its contribution to global warming Problem: - Making new product releases emissions which aren’t good for environment - When product wears out, it becomes waste and is disposed, this causes pollution and making a new one causes pollution too Solution: - Make products using material that has been or can be recycled. Products designed to last or not: - Some products may be designed to become obsolete → useless quickly. This is called Planned Obsolescence Ex: technology, mobile phones are replaced with newer models often. - Built in Obsolescence is bad as more material and energy is wasted for replacement of products. Ex of not obsolete products: Kitchen appliances, utensils, A.C. (repairable) ------------------------------------------------------------------------------------------------------------------------------ - Culture: Changes in fashion and trends: Trends change and this often causes products to become obsolete, this has a negative impact on the environment. Technology impact - CULTURE: - New technology is capable of offending certain people. Ex: If a material is made using animal products. Vegans may choose not to buy that. - Technology can also impact fashion and trends. Products impact - Particular groups in society: - Products can be designed to avoid having any negative impact on people in need. Like disabled or elderly. - People of different religious groups are also considered - If religious symbols are misused it could be an offence. ------------------------------------------------------------------------------------------------------------------------------ - Society and People: Social Footprint: → Taking care of employees Design and manufacture of products impacts people as well. - Working Conditions→ Firms have a moral and responsibility to provide safe working conditions for their employees. - Health Impacts→ Making products can release pollution and negatively affect the  ocean and atmosphere. - Ex: Bleach used to manufacture paper. - Reducing population is important due to potential danger to human health. Entrepreneurs take advantage of Business Opportunities: Innovation → When an entrepreneur or business comes up with something new. ------------------------------------------------------------------------------------------------------------------------------ - Environment: Continuous Improvement → Process by which manufacturers are constantly trying to improve their products. Positive impacts of new products (continuous improvement): Changes in product might result in reduced environmental impact. - They can have more efficient component than older model - Have low carbon footprints - Using more renewable resources Ex: tesla - Avoiding use of unsustainable material - Improve energy efficiency of the manufacturing process. Negative impacts of new products (continuous improvement): It can be harmful to environment for following reasons: - Replacing existing products - High Carbon footprint - Process of manufacture and delivery results in increase usage of finite resources Working out product’s potential environmental impact: Life Cycle Assessment (LCA) → Looks at each stage of life of a product. - From raw material to when it’s disposed of. LCA: 1) Choice of Material - Ex: Hardwood is obtained from rainforests. Trees have to be destroyed with habitat. - Softwood is much better as they can be planted easily. Or recycled wood. 2) Manufacture - Manufacturing products uses a lot of energy and creates pollution. 3) Using the product - Using products can damage the environment as well.Ex: burning fossil fuels (petrol car) 4) Product Disposal - Products are disposed of in landfill sites which takes up space and pollutes land and water. ------------------------------------------------------------------------------------------------------------------------------ - 6Rs 6rs help reduce impact of new products on the environment. - Repair - Better to fix things instead of throwing - Manufacturers can make profit by selling replacement parts. - Re-use - Customers can extend a product’s life by passing it on. Ex: Giving your child your old phone - Recycle - Uses less energy than obtaining new material - Rethink - Think about design carefully.  - Reduce - Making long-lasting durable products. - Refuse - Refuse to buy a product if you think it’s wasteful. - Ex: unnecessary packaging ------------------------------------------------------------------------------------------------------------------------------ - Industry - Process of manufacturing is a system which is split up into 3 stages: - Input (materials, tools, equipment) - Process (What happens to input to change into output) - Output (finished product) Automation of Manufacturing Processes - Use of machines to do tasks automatically without much involvement of humans. - Adv: - Increase speed of production as they are faster and also cheaper in the long term. - Work 24/7 with higher accuracy with less mistakes. - Increase the quality of the product and work in unsafe situations for humans. - Disadv: - Replace human workers, so increase unemployment - Very expensive initially to buy - Don’t work well in unique situations. Smart technology in manufacturing - Smart technology develops machines by connecting them with other machines and sensors in factories to share data. - These machines work without any human input and can receive data about stock levels. - Can be part of IoT Internet of Things - Very efficient for manufacturing Tracking materials, tools, equipment, product - Can automatically tag each box of material or product. - Can be scanned as items move and have a status of item location in the computer system. - Uses: monitoring stock levels, product movement as they are becoming finished products in stock. Communication systems - In modern factories with smart machines human workers don’t need to physically be there and communicate with others through phone, email, or video conference. - Workers on site can use devices (tablets) to collect items, information, find where things are located, etc… Specialised Buildings - Minimise environmental impact (less resource waste) - Modern factories can be made of modular components which can be added to, moved to or removed. - Advances of technology result in less use of space. More robots and automation = less space. ------------------------------------------------------------------------------------------------------------------------------- Enterprise - Can be starting up new business ideas or helping and expanding a current one. This job  is done by an entrepreneur. Innovation: When entrepreneurs or businesses come up with something new. Innovations in Business: - Crowdfunding: To start a new business or idea, entrepreneurs need to raise money. - Crowdfunding involves using websites to promote an idea to an audience. People can choose to invest and those people are called Backers. - Backers get some reward or discount for investing. - Virtual marketing and virtual retail - Marketing: Promotion of a product or service - Retail: Selling products and services to customers. - Virtual Marketing: Includes promoting product/service on social media/email. - Virtual Retail: Selling products and services on the internet. - Co-operatives and Fairtrade - Co-operative: Type of business that is owned and run by its members. They make all the decisions on the business. - Groups of farmers often form cooperatives to have stronger negotiating power. Market Pull → What consumers want - Designers design stuff to meet consumer demand as there is a need in the market. Technology Push → What Manufacturers can provide - Research and development to come up with new technology, materials which are better than existing products. - This can have a positive impact on the product as new technology might be more efficient. Jobs people do - TECHNOLOGY’s IMPACT: - Technology is always developing and has an impact on jobs available. - Increase in automation can decrease employment. - But it can also increase employment, Ex: for writing computer programs. Supervising the AI robots as a staff. - Tech has also led people to change jobs. ------------------------------------------------------------------------------------------------------------------------------ - Production Systems - CAD/CAM 2 Other ways of maximising efficiency 1) Flexible Manufacturing Systems (FMS) - Different machine carry out different production stage - Easy to adapt, quick and accurate, getting more human-friendly interfaces. - Easy to increase/decrease level of production changes ( add more machines ) 2) Lean Manufacturing - Minimise resources used, waste produced and cost of production and maximise efficiency. - JIT (Just-in-Time) → form of lean manufacturing. Material and components are delivered only as they are needed as soon as they arrive. - Advantage : Reduces space for storage, less material and money waste. - Disadvantage : Must deliver on time and must be fault free, if not then money lost CAD - CAD = Computer Aided Design  - Involves design on products on computer in either 2D or 3D. - Ex of CAD software: TechSoft, Adobe Illustrator, Onshape, Cura, Shaper CAM - CAM = Computer Aided Manufacture - Involves manufacturing products using computers and subtraction or addition of material - Datum - point where (x,y,z) = (0,0,0) (can be a reference point) - Subtraction → material is removed from object (ex: milling machine - CNC router) - Addition → material is added - Some have 2-axis (cut 2D shapes), some have 3-axis (cut 3D shapes) - Some machines: 1) CNC Router - Cut 2D/3D shapes and can have 2-axis/3-axis - Used to engrave/cut on plastic, wood and metals. 2) Laser Cutter - Used to cut/engrave on plastic, wood, cardboard, fabric, some metals. - Can have different power settings and speed settings. - Only have 2-axis 3) 3-D printers - Rapid prototyping - Can be printed with plastic and wax - Sometimes used in final products as well. Benefit Drawback - Saving on shipping cost as design can - Computers can be affected by virus and be sent electronically (CAD) file corruption which could slow processes - Can be manufactured anywhere down. - Offshoring → workers exploitation - Benefit of automations as get paid less and taking advantage of - Save labour cost their situation (ethics) (optional one) - Manufacture in different country with cheaper access and import back 1.2 Energy Generation and Storage Non-Renewable Energy = Finite Non-Renewable: A substance that is used up quicker than it can be replaced. Fossil Fuels - Non-renewable / natural resources → Coal, Oil and gas - They are burnt to heat water and convert to steam - The steam turns the turbine in a generator which causes electricity to be generated. - Adv: Reliable, produce large amounts to meet demand, low cost to run and extract. - Disadv: Finite, extraction has social and environmental impact, causing greenhouse gas release → global warming. Nuclear Power - Work similarly except using a process called nuclear fission to heat water. - Adv: Reliable, cheap, clean, produce less greenhouse gas. - Disadv: Finite (uranium), cost a lot to maintain/build, waste produced is dangerous and hard to dispose, risk of a major disaster.  Renewable Energy = Non-finite Renewable: A substance that can be replaced quicker than being used. Ex: softwood - Wind Power → wind directly turns turbine - Solar cells → convert light energy into electricity. - Tidal → Big dams built across rivers, electricity generated by flow of water/tide. - Hydro-Electric → Pressure created from water going through a turbine in a dam. - Biomass → using manure and faeces rather than fossil fuels to burn. Adv: Have smaller environmental impact, provide clean energy, energy provided is free (after initial costs) Disadv: Initial set up costs are high, take time to set up, rely on external factors (less reliable), noisy, can have impacts like flooding, can’t produce that much energy. Storing Energy - Energy is made at night as well and it's used less during those times, we need a medium or a storage equipment to store extra electricity. Kinetic pumped storage system - Uses a hydro-electric power station - The spare energy is used to pump water in lower reservoirs up to higher reservoirs. - Water can be released from dams and flow through turbines in peak demand to generate more electricity. Alkaline Batteries Rechargeable Batteries - Normally disposable, recyclable and last a long - When it runs out, electricity reverses chemical time - leak less and have reduce environmental reactions and reforms chemicals for it to work impact - Power output decreases over time (-) again. - expensive initially, cheaper at long run - Use: toy, remotes, torch, clocks - More environmentally friendly (can use again) - Power output is constant - Use: phones, laptops, electric cars 1.3 Developments in New Materials Modern Materials Modern materials → materials that have been developed with specific application in mind, they are invented by new or improved manufacturing processes. (better than traditional materials) Examples: - Graphene - Super thin layer of graphite (stuff used in pencil) - It’s light, strong and is a great conductor. - New manufacturing processes have been made to provide this product cheaply. - It’s used in modern tennis racquets. It might further be used in vehicles. - Metal Foams - It is a metal containing gas-filled spaces - It’s light, stiff, tough, and strong under compression - It’s used for lightweight car parts and bone implants.  - Titanium - Extremely corrosion-resistant metal with high strength to weight ratio. - Process in 1930 allowed it to be extracted easily and cheaply. - It’s main use is in the aerospace industry. Some modern materials are made by altering existing material to perform particular functions. Examples: - Liquid Crystal Displays (LCD) - Thin, lightweight and energy efficient. - Liquid crystals used in display are made of a mixture of chemicals. - LCDs were used in calculators and small displays but are now used in flat screen displays. - Coated Metals - Coating metal with different materials to alter their properties. - Metals can be coated with PVC as its corrosion resistant and can be coloured - Ex: Iron is coated with zinc to be galvanised. It won’t get rusted therefore. - Nanomaterials - Made of tiny(nano) particles. They always existed but we are able to manipulate it for specific purposes now. - Ex: Carbon nanotube → Tiny carbon cylinders with high strength to weight ratio and good conductors. They can be added to add much weight (in tennis racquets) - Antibacterial fabrics use nanoparticles of silver to kill bacteria. Smart Materials Smart materials→ They change their properties in response to stimuli. Ex of stimuli: temperature, light, ph, moisture. - Shape memory alloy → Allos that remember their original shape. They can be easily shaped as cool but return to their original shape if heated - Ex: nitinol. If you bend it and pop it into hot water, it will return back to its original shape. Nitinol glasses → you accidentally bend them they return back to original shape - Photochromic pigments → change colour reversibly in response to light - Can be put into lenses that turn into sunglasses when in the sun. - Thermochromic pigments → used in colour changing product - (they react to temperature) - As temperature changes colour changes, colour changes back as temperature changes back. - Ex: Baby feeding spoon → so parents know food is not too hot. Composites Composites → combination of two or more materials bonded together. They often have different and more useful properties than they had as an individual property. Ex: Composite Made from Property Uses Glass reinforced Glass fibres Stronger, tougher Kaya, boat, PCBs plastic (GRP) coated in than plastic, heat thermosetting resistance plastic resin  Carbon Fibre Carbon fibres Lighter, tougher, Protective helmet, reinforced plastic coated in stronger, (expensive) racing car, laptops (CRP) thermosetting plastic resin Technical Textiles Technical textiles → enhanced fabrics. They are designed to be functional rather than look good Ex: Bullet proof vests made of kevlar - Some synthetic fibres are designed to be fire-resistant. They can’t be washed or worn away. Used in firefighters. - Micro encapsulation - Tiny droplets of chemical coated in shells → microcapsules. They have function use as example: perfume, mosquito repellent. - Conductive fabrics - Use fibres that can conduct electricity. - Used to integrate electronics into clothing and in touchscreen gloves. 1.4 Systems Approach to Designing Electronics Systems Systems contain → Input, Process , Output A signal passes from each stage to the next. Each stage changes the signal in some way. Ex → Cycling: Input → Turning cyclist leg and pedalling Process → In chain and sprockets Output → Rear wheel, bike moving forward Circuit → made up of components joined together by wires Most electronic systems use PCB (printed circuit board) → They are used to reduce manufacturing cost and size. - Materials in circuit: Conductor (copper), properties → ductile, malleable, good conductor - Voltage pushes the electrical current around circuit - Resistors reduce current. Larger R = Less I Input Input devices change electrical current in Circuit. They receive an external signal which triggers the system to work. - The signal usually comes from a sensor. - Various types of input devices are used. Ex: switches, variable resistor, thermistor. 3 types of switches → Toggle switch, push switch, slide switch. You can toggle to turn off/on or push or slide. Variable resistors → detect change in external condition. They change the resistance of the circuit depending on external factors. Types of resistors: - Thermistor → detects changes in temperature. Hot = low resistance - LDR (Light dependent resistor) → detects changes in light intensity. Bright = low resistance - Pressure sensors → detects change in pressure. Depends on which type of pressure sensor is used as it can increase or decrease resistance. - Often used in cars for fuel systems. Processes Process Devices → Make all decisions in an electronic system. They process input and determine output. Integrated Circuits(IC) - can carry processing in electronic system - They are self-containing circuits and can be complicated. - Help to simplify electronic systems by reducing separate components needed in circuits. - They are small, cheap, portable and use less power. Microcontrollers - It's a mini computer on a chip, it contains processor memory and one or more input, output. - They are found in a lot of electronic products. - Advantage: They can do the job of many ICs(simplify further) and can be reprogrammed - Disadvantage: They are more expensive - They need to be programmed for a particular function. This program is stored in onboard memory. - PCB and Arduiono boards are examples of microcontrollers. - The programming is done by a logicator or computer software specialist. Microcontroller as Timers and Counters - Timers and counters need work by responding to pulses in the circuit. - Timers → Used to add time delay to process and make sure everything is running where it's supposed to be. They generate a pulse after some time. - Counters → Differ from timer as they count pulses of voltage produced by input device. Microcontroller as timers - Controlling car indicators, using timers to turn light on and off. - In microwave as timer Microcontroller as Counters - Cars have a dial that shows how fast the engine is turning (number of revolutions per minute). Microcontroller is used to count revolutions. Microcontroller as Descicion Makers - Logic gates make decisions in ICs, based on collection of inputs. - Logical gate names: - OR gates: They have two inputs, if one of them is on, then output on. - Ex: automatic door. If someone comes from either side it will open. - AND gates: They have two inputs, both need to be on, then output on. - Ex:Car won’t start until foot on break and on button pressed. - NOT gates: They have one input, if one input on, then output off. - Ex: Pressing the emergency button will stop the escalator rather than make it move. Outputs Output device → Determines how the system responds to input signals. - Loads of output devices. - LED: Turn electricity into light - Buzzer: Makes a noise (Used in alarm to wake up) - Speaker: Turn electrical signal into sound (ex: headphones) 1.5 Mechanical Devices Magnitude and direction of force Mechanical Systems All mechanical systems have mechanisms which transform: Input motion and force into output. - They are designed to gain mechanical advantage. → They make jobs easily. (They can change magnitude and direction of force applied) Types of motion - Linear motion → moving one way in straight line - Reciprocating motion → moving backwards and forward in straight line - Oscillating motion → moving backwards and forward in arc - Rotary motion → moving in circle Ex of Mechanical system: Lever → moves and lifts load by rotating stationary object, (pivot = fulcrum) Types of lever: First Order lever - Have pivot between effort and load - If load is closer to pivot than the effort, large load can be lifted with small effort (mechanical advantage) - Ex: Scissors Second Order lever - Pivot ist one end, effort on other. Ex: Wheelbarrow - Closer the pivot and load, easier to lift. - Ex: Car door Third Order lever - Effort is in between load and pivot. Ex: fishing rod, a bat - Moving pivot and effort further apart makes it easier to lift load. - Ex: Broom Linkages Simple linkages → Can change magnitude of force and direction of motion. - Push pull Linkage - They use two fixed pivots - Input output linkage in the same direction. Linkarm motion in opposite direction. - Pivots are fixed in centre and changing location, changes magnitude of force put - Bell Crank - Changes direction of force 90 degrees. - Magnitude can be changed by moving the fixed pivot. Rotary Systems Gears Gears → toothed wheels that interlock. They transfer motion from one part to another. Gear train → two or more gears linked together. Driver gear → turned by hand or motor Driven gear → gear being turnt by driver gear (it will be opposite direction) Idler → the third gear in middle to have driven gear same direction as driver gear Gear ratio = no. of teeth on driven gear / no. of teeth on driver gear Output speed = speed of driver gear / gear ratio (unit: rpm (rotation per min)) Pulleys and Belts Simple pulley → made up of a wheel with grooved outer edge and a cable rope which sits in the groove. Pulley → eases lifting - One pulley doesn’t give any mechanical advantage. - Two or more pulleys together change magnitude of force. Belt drive → transfers movement from one rotating shaft to another, ex. in pillar drill - Pillar drill → a flexible belt joins two separate pulley weights. - Belt can be put in different positions to make drill turn fast/slow Velocity ratio = diameter of driven pulley wheel / diameter of driver pulley wheel Output speed = speed of driver pulley wheel / velocity ratio Cams Cams → Changes rotary motion to reciprocating motion - Has two parts: cam, follower - They come in different sizes and always rotate - Follower rests as the cam rotates and follows its shape. Cam shapes - Circular cam - produces uniform reciprocating motion - Snail cam - for half turn follower doesn’t move, then gently rises and drops. Rotates in 1 direction only - Pear cam - for half turn follower doesn’t move, then gently rises and drops. - Four-Lobed cam - has 4 lobes. It rises and suddenly falls 4 times. Rotates in 1 direction only Changing size and shape can change the magnitude of output motion. 1.6 Materials and their Working Properties Different materials have different properties; Mechanical Properties/Working Properties: Strength: Ability to withstand forces without breaking Test → Compressing Ex: Surfboard resists forces trying to bend it 2 TYPES of forces: Compression force and tensile string Hardness: Ability to withstand scratching and denting Test → Scratching/Denting (hardness is important for tools that cut ( ex: drill )) Toughness: Inability to break or snap. Test → By breaking Elasticity: Elastic materials can stretch/bend and return to original shape. Test → If it goes back to original shape (Ex: spring) Malleability: Ability to shape and form objects. Test → By shaping Metals → most metals are malleable (can be hammered into thin sheets): without breaking Ductility: The ability to stretch an object without breaking. Test → Stretch it Used in wires most commonly → material’s ability to be drawn into a wire without breaking Physical Properties: Fusibility: Ability to change a solid state object to liquid Material with high fusibility have low MP (Ex: soldering wire) Density: The denser it is, the faster it sinks Absorbency: Ability to absorb Test → Different things that it can absorb (water/gas/moisture) Absorbent material can get dyed easily but take longer to dry Natural fibres are absorbent Synthetic fibres are not absorbent Electrical Conductivity: Ability to let electrical currents pass through Test → see if current passes through Insulators → poor electrical conductors Conductors → good electrical conductors Thermal Conductivity: Ability to let heat energy pass through Test → Check how fast material gets hot Insulators → poor thermal conductors Conductors → good thermal conductors Properties Hardwood Softwoo d Strength Hardness Toughness Elasticity Malleability Ductility Fusibility  Density Absorbency Electrical Conductivity Thermal Conductivity Softwood: Type of wood Info Pine - Strong, cheap and knotty. This makes it hard to work with - Used for fence/cheap furniture Larch - Harder, tougher, durable. Resistant to rot - Used as fence posts Spruce - Hard, good strength to weight ratio, not durable and knotty. - Used in aircraft, crates Hardwood: Type of wood Info Oak - Tough, durable and very strong. Attractive grain marking and finishes well. Disadvantage: Corrodes steel - Used in flooring, furniture Mahogany - Durable, easy to work with, expensive - Used for good quality furniture Beech - Hard, can be bent using steam - Used for good quality furniture Balsa - Low density, soft, easy to cut and shape. High strength to weight ratio. - Good for modelling Ash - Tough, absorbs shock well. - Used for tool handles and wooden sports equipment. Types of paper and board Types of paper Info Types of board Info Cartridge paper High quality Solid white board Ideal for printing, high quality Layout paper translucent Inkjet card For inkjet printing, high quality Tracing paper semi-transparent Corrugated card Flutes inner core which add strength. Useful for  packaging Grid Paper (isometric) Contains square Duplex board Used for food packaging Bleed Proof paper No ink spill Foam core board Made of sandwiching expanded polystyrene foam -------------------------- --------------------- Foil Lined board Aluminium foil lining. Used for food packaging. Foil keeps moisture out. Metal Properties; Ferrous: Any metal that contains iron → easily rusted - Their base metal is iron Non Ferrous: Any metal that doesn’t contain iron in it → not rusted - Their base metal isn’t iron (in general) → not specific to any ferrous or non-ferrous metal. Properties Ferrous Non-Ferrou s Rusts Strength Hardness Toughness Elasticity Malleability Ductility Fusibility Density Absorbency Electrical Conductivity (more) Thermal Conductivity (more) Alloy → Ferrous and Non-Ferrous Ex: Brass [65% Copper, 35% Zinc] Type of Alloy % of element  Aluminium Alloys Wrought Aluminium Alloy