DT Flashcards
Compressive strength definition
the capacity of a material to withstand loads
Tensile strength definition
The ability of a material to stretch without breaking/snapping
Toughness meaning
The ability of a material to absorb sudden shock without breaking or shattering
torsion definition
Force of an object being twisted
What’s a beam’s purpose?
supports a structure’s weight
What force do struts act against?
Compression
What force do ties act against?
Tension
Frame structure definition
The fitting together of pieces (eg beams, ties and struts) to give a structure its strength
What is a shell structure?
Structure that gains its strength by the way its shaped
Measuring
Estimation, precision and creating designs ideas using CAD for accuracy
Cutting and shaping
Selecting the correct tools and machinery for specific processes
Fabrication
• Joining of materials
• gluing/assembling of materials and quality control at each stage
Finishing
Accuracy of product in relation to form, function and user.
Material properties definition
The characteristics of a material and how they help it function
Wind power definition
• When wind movement is harnessed to generate electricity
• Eg on windy days, propellers in wind turbines spin a generator to generate electricity
Solar power definition
Conversion of energy from sunlight to electricity eg solar panels
Hydro power definition
• When the force of moving water is harnessed to generate electricity
• Eg as dams release water it spins a turbine connected to a generator to produce electricity
Geothermal power definition
• When heat produced in the Earth’s core is harnessed to generate electricity
• Eg geothermal power plants use the steam’s heat to drive an electrical generator
Biomass energy
• When organic matter is used as fuel to generate electricity
• Eg wood is burned to power central heating systems
Reduce definition (6Rs)
To cut down on the amount of products and services you use
Reuse definition (6Rs)
Taking a product and changing its purpose for something else
Rethink definition (6Rs)
Designing in a way that considers people and the environment
Repair definition (6Rs)
Fixing a product that doesn’t work properly
Refuse definition (6Rs)
deciding not to use a material if it’s not needed or has a negative impact on the people or environment
What are the 6Rs?
Reduce, reuse, recycle, repair, rethink, refuse
Hard wood (loses/keeps their leaves)
Loses their leaves
Soft wood ________ their leaves
Keeps their leaves all year
Plank meaning
Long piece of wood
Moulding
when a material is shaped from a mould template
Methods of cutting and shaping wood
File, drill, sand, plane
Hardwood characteristics
• Weather resistant
• The water repels during rainfall
• From deciduous trees
Softwood characteristics
• Not weather resistant
• Absorbs the water during rainfall
• From conifer trees
CAD
• Computer Aided Design
• Computer software used to develop design ideas
CAM
• Computer Aided Manufacturing
• Computer - controlled machinery used to manufacture a product
Pros of CAD
• Increased accuracy compared to hand drawing
• Saves time (no prototype to build)
• Can be sent anywhere
Cons of CAD
• Training is needed which requires time and money
• Work can be lost if not saved
Types of coatings
• Wax
• Stain
• Varnish
• Oil (sinks into the surface)
• Paint (covers the surface)
Manufactured board examples
• Plywood
• MDF
• Chipboard
• Hardboard
• Veneer
Plywood definition
• Thin layers of wood veneer glued together at right angles
• Used in furniture and structure
MDF (medium density fibreboard)
• Small particles of wood that have been compressed with a random orientation for a solid finish
• Absorbs moisture therefore not suitable for outdoors
Examples of wood stock forms
Sheets, mouldings and planks
What stock forms does MDF come in?
mouldings and sheets
What impact does MDF have on the environment?
• Made from leftover wood fibres reducing waste and saving trees
• Isn’t biodegradable and would release poisonous chemicals if disposed of incorrectly
The 2 categories of plastic
Thermoplastic and thermoset
Difference between thermoplastics and thermosets
Thermoplastics can be heated whereas thermosets can’t due to its strong covalent bonds
Plastic’s source of origin
Crude oil
Stock forms of plastic
Sheets, extrusions, plastic polymers
Stock form definition
The form a material is sold in
Methods of cutting and shaping for plastic
Blow moulding • vacuum forming • injection moulding • heat cutting • laser cutting
Finishes for plastic
Matt or gloss however it doesn’t require a finish
Why do plastics not need a finish?
They don’t rot or corrode
Mechanism meaning
When components work together to make a product function
What are the 4 types of mechanisms?
CAMs, linkages, levers and gears & pulleys
Linear movement
Movement in a line going in one direction
Oscillating movement
swinging motion going backwards and forwards
Rotary movement
Going round and round in circles
Reciprocating movement
Going up and down / in and out
What 2 movements are involved between the cam profile and follower?
Rotary is converted into reciprocating
Types of cam profiles
Drop (snail), heart, pear and eccentric (circular)
Plastic’s impact on environment
• Difficult to dispose of and can release poisonous chemicals
• Manufactured from crude oil (greenhouse gas emissions released)
How does a linkage mechanism work?
Combination of levers connect to move an object or change direction of a force eg bikes
Mechanical Advantage
When the force of a mechanism is multiplied to make things easier for the user
characteristics of a 1st class lever
The fulcrum (pivot) is in the middle of the effort and load (eg see saw)
characteristics of a 2nd class lever
the load is in between the fulcrum and effort (eg wheel barrow)
characteristics of a 3rd class lever
the effort is in between the fulcrum and load (eg fishing rod and baseball bat)
Effort meaning
Force or energy applied
Pivot meaning
Point of rotation
Load meaning
Object that is being moved
How do gears work
Its teeth interlock with other gears to rotate and change the speed or power of an object
Tolerance meaning
Clearances in mechanisms to allow movement with minimal friction
Clearance meaning
small gaps between moving parts that allow for smooth movement
extrusion meaning
When a material is forced through a small opening to shape it
Smart material meaning
Materials with the ability to change their properties depending on a change in their surroundings.
Examples of smart materials
• Photochromic paint (which changes colour when exposed to light)
• Reactive glass (changes transparency when current flows through)
• Shape memory alloy (programmed to remember original shape and made from nickel and titanium)
Veneer meaning
A thin decorative covering of fine wood applied to a coarser wood
Adhesive meaning
A substance which bonds the surfaces of materials together (eg glue)
Malleable
Describes materials that are able to bend or shape easily
Why is nature studied as a way to develop new materials?
• How nature adapts to its environment provides a source of inspiration for designers to mimic its functionality • (Eg The way birds fly inspired design of aircrafts)
Why are smart materials used in the fashion industry?
To inspire new trends and lead the market increasing amount of profit
What are components?
They’re universal and tend to be bought as it’s designed by specialists • Used to assemble and install fixtures and fittings
What are fixtures and fittings?
Fixtures - Items attached or fixed to property
Fittings - Not attached to property and can easily be removed
Examples of fixtures and fittings
Fixtures - Sinks, ovens and radiators
Fittings - Pictures and furniture
What are nails?
Small, pointed metal fasteners used to join materials together by friction
What are screws?
Metal fasteners that use rotational force to tear into a material and hold materials together
What are nuts and bolts?
Components that lock together along a threaded shaft
• They’re precise and have minimum tolerance
• (Semi permanent fasteners)
What are knockdown fittings?
• A type of fitting that can be put together easily by using basic tools • (Often used in flat-pack furniture)
What are permanent fasteners ?
• Components that permanently join 2 materials together and can’t be removed once installed
• Eg Nails permanently attach a frame to wall
What are semi permanent fasteners?
Components that hold objects together but aren’t permanently fixed (Eg Nuts and bolts)
Batch production meaning
When a certain amount of identical products are produced (eg clothing)
Mass Production
When a large amount of products are produced at a time (in order to meet demand eg phones)
Continuous production
Production that occurs every day non-stop (eg newspapers)
JIT (Just In Time) Production
Made in response to an order instead of being produced beforehand (to reduce money lost eg Ferraris)
Prototype / First Generation Model meaning
An early sample or model of a product built to test a concept
Describe the benefits of a Production Line
• Workers specialise in one aspect (increasing efficiency)
• Increases the speed and production rate
• Reduces waste
Jigs function
They hold something in place in the process of production to increase accuracy
QC meaning
• Stands for Quality Control
• Procedures or tests carried out during manufacturing to check for quality
Tessellation meaning
Repeated pattern of geometric shapes with an exact fit
Nesting meaning
fitting irregular shapes as close together as possible to minimise waste
Template meaning
A mould or pattern used as a guide to make something
What is CAD CAM?
Using a computer to make a drawing which will be interpreted by a machine eg laser cutters
What is a 3D printer?
• A method of constructing 3D objects using CAD where layers are built up
• Also referred to as additive manufacturing
What is a CNC router?
• It’s an acronym for Computer Numerate Control
• A spinning drill that works on 3 axes (x,y,z) and cuts into a material
What is planned obsolescence?
• Designing products to break quickly or become obsolete (out of date) to encourage the sales of new products
• Eg mobile phones or vehicles
Market pull definition
When the market encourages firms to produce new technology to meet demands eg camera development
Technology push meaning
When technology advances enough to develop new products before consumers demand for it (eg smartphones)
Ergonomics meaning
• The study of how products are designed to minimise effort and discomfort
• eg how a person rests on the back of a chair
Anthropometrics meaning
• How a product suits a person’s size using body measurements
• eg key sizes on a keyboard
Examples of ergonomic and anthropometric design
• Fender’s electric guitar has curves on both of its sides to fit around user’s stomach or their legs
• Tuning pegs are all on one side therefore it’s easier to access
• Sportswear are lightweight, breathable and don’t restrict body movement
Importance of designers using ergonomic and anthropometric data
• The product becomes suitable for how the user functions (maximising productivity)
• Attracts the market as the product has a personalised design (which would increase revenue)
What does green represent in safety signs?
• They direct and lead people to safety. • Eg fire exits
What does blue represent in safety signs?
• They are mandatory signs
• Usually give information
• Eg wear goggles
What does red represent in safety signs?
• They are mandatory signs usually meaning ‘no’
• Eg no entry
What does yellow represent in safety signs?
• They are warning signs and alert us to danger
• Eg radioactive chemicals
How does a pulley mechanism work?
• A wheel on a fixed axle with a groove in it to guide the rope
• The rope is attached to the load
• The pulley changes the direction or the amount of the force needed to lift the load
Explain input - process - output
Input:
• The force applied on the mechanism
• Eg turning a crank ; pressing a button
Process:
• Physical interactions within the mechanism converting the input to output
• Eg cams rotate causing the followers to move
Output:
• The resulting force / movement produced by the mechanism
• Eg lifting a weight using a pulley
What are the 4 motions?
• Linear
• Oscillating
• Rotary
• Reciprocating
Examples of hardwood
• Beech
• Oak
• Teak
Examples of softwood
• Pine
• Spruce
• Fir
Examples of plastic
• Polypropylene (PP)
• Nylon
• High density polyethylene (HDPE)
• Low density polyethylene (LDPE)
Hardness meaning
The ability of a material to resist scratching, wear and tear, and indentation
Laser cutting CAM process
• Takes info from the computer
• Follows x and y coordinates
• Burns the material instead of cutting it
• Red lines informs the machine to go slow
• Black lines informs the machine to go fast and etch through the material
Two categories of metal
Ferrous and Non - ferrous
Ferrous meaning
Metal that contains iron and therefore can rust/oxidise
Non - ferrous meaning
Metal that doesn’t contain iron so won’t rust
Metal source of origin
Rocks/Ores
Stock forms of metal
• Sheets
• Girders
• Tubes
• Bars
• Nuggets
• Beams
Methods of cutting and shaping metal
• Water - jet cutting
• Plasma cutting
• Laser cutting
• Drilling
• Filing
• Sawing
What is an alloy?
A mixture of metals to improve chemical properties
Examples of alloys
• Brass - An alloy of copper and zinc
• Steel - An alloy of iron and carbon
Finishes that can be applied to metals
• Paint dip coating
• Paint powder coating (using static charge)
• Electroplating
• Greasing
• Oiling
Metal’s impacts on the environment
• Metal cycling preservers natural resources and reduces the emission of greenhouse gases
• Metal extraction however may require deforestation which erodes the soil and decreases levels of biodiversity
• Scrap metals can release toxic chemicals and contaminate the ground
