EDUQAS A level DT Theory

Why should designers strive to ue corn starch based polymers?

Sustainability (corn starch is fully biodegradable)

Outline what is meant by a 'SMART material'.

A SMART material is one which reacts to external stimulus or input

Outline what is meant by a modern material

A modern material is a materials developed through the invention of new or improved processes

What is the purpose of a tolerance on an engineering drawing?

Tolerance is the amount a dimension may vary. This allows manufacturers to understand the accuracy needed for varying dimensions.

What is a sectional view and why is it important?

A sectional view looks inside an object. This allows relevant parties to see the interior of a product.

Explain the benefits of incremental innovation to the manufacturer.

-Reduced risk in comparison to radical innovation

-Can improve a service for users, increasing brand loyalty

-Continually makes a product more competitive

Name two industrial tests used to measure hardness.

1. Brinell hardness test

2. Vickers hardness test

Why is a specification important?

A specification ensures the subsequent design and development of a product meets the needs of the user.

Explain what properties carbon fibre has which make it suitable to make tennis rackets with.

Carbon fibre is very strong when stretched or bent.

What is a drawback of carbon fibre?

It is weak when compressed or exposed to high shock.

What are typical applications of glass reinforced fibre (GRP)?

Boat hulls, storage tanks

What are the drawbacks of glass reinforced fibre (GRP)?

Labour intensive to manufacture, problems with toxic fumes

What is a regenerated material?

Materials that have been made from other raw materials e.g. MDF, paper

How does ductility differ from malleability?

Malleability refers to a material's ability to withstand compression whilst ductility refers to a material's ability to withstand being stretched.

What is qualitative and quantitative data?

Qualitative data focuses on subjective non numerical elements whilst quantitative criteria are numerically measurable elements.

Outline the benefits of iteration.

- Iteration allows for rapid resolution of misunderstandings within the project team

- Brings out user feedback to ensure user needs are met

- Gives stakeholders better visibility of progress at each iteration

Outline 3 key features of batch production.

1. Production can be adjusted to suit demand (flexible)

2. Often carried out by skilled workforce as range of processes are involved

3. Often utilises machinery which can be used for a range of products

State a suitable plastic to use for drainpipes and guttering.

Polyvinyl Chloride (PVC/uPVC)

What properties of polypropylene make it suitable for food packaging?

Food safe, good barrier to moisture, resistant to stress cracking

List 4 advantages of using plastic.

1. Lightweight & versatile

2. Strong/tough, resistant

3. Easily formed & moulded

4. Easily printed on

List 4 disadvantages of using plastic.

1. Non-renewable

2. Brittle at low temperatures

3. Deforms under load

4. Produces toxic fumes when burnt

What is meant by plastic memory?

Each time a thermoplastic is reheated it will try to return to its original shape.

What are synthetic polymers and why are they controversial?

A synthetic polymer is a type of polymer made by engineers & scientists from artificial components rather than natural ones. They are controversial due to their environmental impact (they are derived from petrolium oil).

Suggest a suitable material for tool handles.

Ash

Suggest a suitable timber for buoyancy aids.

Oak

Which has greater toughness, glass or rubber?

Rubber

State 4 applications of copper

1. Wire

2. Pipes

3. Pans

4. Coins

What are the stages of an average product life cycle?

Introduction, growth, maturity, decline

State 4 properties of copper.

1. Malleable

2. Ductile

3. High electrical conductor

4. High thermal conductor

Discuss the relative merits of destructive and non destructive testing of materials.

Destructive testing is easy to interpret and economic in cases of mass production. However, non-destructive testing is more suitable in a case where fewer or only one product is produced e.g. a building.

Define fatigue

Fatigue refers to how a material changes with wear and tear.

Name 2 metals with high thermal conductivity.

1. Aluminium

2. Copper

Name two products that have been developed from a technological push.

1. Wireless headphones (due to bluetooth)

2. Waterproof watches/ technology

List 5 important factors which influence decisions about materials.

1. Availability of material

2. Cost of different materials

3. Properties of various materials

4. Any special maintenance requirements

What are the benefits of using concurrent engineering at the design stage of product development?

Correct implementation of the concurrent design process can save massive amounts of time and money. It is also highly compatible with systems thinking of green engineering.

Give two examples of corn starch based polymers and describe their application.

1. Polylactic acid (PLA) - widely used in 3D printers

2. Polyhydroxy butryrate (PHB) - used for household items and disposable food containers

Fibre optic cable is fast replacing traditional copper wire. What benefits does this have for broadband and communications?

Optical fibres allow digital information to travel as pulses of light along thin glass strands at very high speed. They can carry much more information than traditional copper wires do and do not suffer from electromagnetic interference which can distort the signal.

What are nanomaterials and why is their development important?

Nanomaterials are materials between 1 and 100 nanometres (nm). They are very important for developments in electronics and engineering.

Describe what is unusual about graphene and what its likely future uses will be.

Graphene is unusual as it is a truly two dimensional material - the thinnest yet discovered. It is also the most conductive material known. It may be used in electronics, biomedicine, materials coating etc.

What is the objective of creating genetically modified wood? Outline the drawbacks with such practice.

The aim of genetically modified wood is to provide:

- Quicker growing trees

- Trees that are more resistant to rot and insect attack

- Trees with reduced lignin

There are ethical concerns with 'tampering with nature'

What is the Health & Safety Executive (HSE) and what is their role?

HSE is the national independent watchdog for work-related health, safety and illness

Outline two responsibilities employees have to ensure their well being in the manufacturing workplace.

1. Take reasonable care of their own health and safety as well as others around them.

2. Use personal protective equipment (PPE) and use machinery in accordance with given training instructions.

The Health & Safety at Work Act 1974 is the main legislation in the UK covering health and safety in the workplace. Briefly outline what the act does and the principle method of achieving its aims.

The HSWA ensures that employers make sure that all employees and visitors are safe. This is done through carrying out risk assessments and creating safety precautions based on the results of said assessments.

Under the Control of Substances Hazardous to health regulation (COSHH) 2002 the employer must minimise employees' exposure to hazardous substances. Describe three categories of said substances found in the workplace.

1. Paints, varnishes, adhesives, cleaning agents

2. Fumes produced from processes such as soldering

3. Airborne particles e.g. dust from sanding

The COSHH regulations require employers to consider a number of factors. Briefly describe what these factors are.

1. Plan processes to keep emissions to a minimum.

2. Consider all routes of exposure including inhalation, skin absorption and ingestion.

3. Control exposure by appropriate methods

4. Choose the most effective control options

5. Provide appropriate PPE

6. Inform an train all employees

etc.

What is the purpose for each of the following:

1. Jigs

2. Formers

3. Templates

4. Patterns

5. Moulds

1. parts made exactly the same without marking

2. parts are shaped or bent

3. draw around an irregular shape

4. make a mould and replica of finshed object

5. hollow shapes used when casting metal or plastic

How does vacuum forming differ from thermoforming?

In thermoforming an additional mould is pressed onto the surface of the polymer sheet at the same time the vacuum is applied. The extra mould gives extra detailing to the surface of the polymer either for decoration or for strengthening.

Describe why vacuum forming is a far less expensive process than injection moulding. Outline one principle drawback with vacuum forming.

Vacuum forming is very inexernsive as moulds are often made simply from wood, resin or dense foam which can be made on the CNC router. A drawback is that absorbed moisture can expand, forming bubbles within the platic's inner layer - this greatly weakens the plastic.

What is meant by 'fabrication'?

Fabrication describes joining together individual pieces of material using adhesives, welding or mechanical fixings like nuts and bolts.

What is meant by 'casting' or 'moulding'?

Casting and moulding processes involve pouring or forcing fluidised material into a mould or die.

What is meant by 'cutting' or 'wasting'?

Effectively the process is cutting a solid mass to form a desired shape.

What is meant by 'forming'?

Forming processes involve bending, stretching or squashing a material to form a new shape.

Briefly outline the four stages of manufacture.

1. Preperation or primary processing - the stage of getting the raw material into a workable state.

2. Secondary processing - forming the material

3. Assembling - the stage of joining components (adhesives etc.)

4. Finishing - completed in order to protect or enhance the appearance of the product

Why do designers need to take into account the scale of production for the products they are designing?

To choose the most economic route of production

What are the 5 points of a risk assessment required by the HSE?

1. Hazard

2. Risk

3. Evaluate and decide Control

4. Record and implement Control

5. Review

Outline the difference between a hazard and a risk.

A hazard is anything that could cause someone harm. A risk is the likelihood or chance that someone may be harmed as a result of the hazard.

What is a risk assessment? Where should it be used?

A risk assessment is something that an employer is required by law to carry out; it must consider what might cause harm to people and suggest reasonable steps to prevent this harm. It should be used in a manufacturing workplace.

Distinguish between blue, yellow, red and green signage.

- Red signs are prohibitive

- Yellow are warnings of hazards

- Blue signs give instructions of specific action to be taken

- Green are locations

What is a jig and why is it useful?

Jigs are devices which speed up production whilst ensuring accuracy.

Describe harboard's use

Hardboard (HDF) has long been used in furniture, but it is also popular for use in the construction industry and with trades as a temporary floor protector.

Define and explain how a product can be evaluated to be of a highly quality.

FIT FOR PURPOSE!!!!

Selling price

product compared with similar products (shows competitiveness)

reliability

features product should have to sell

attempt to sustain brand loyalty

Why have metalised films failed to replace the less sustainable aluminium foil for food packaging applications?

It was thought that metalised films would become a replacement for aluminium foils, but current films still cannot match the barrier properties of foil.

What are metalised films and what are they typically used for?

Metalised films are polymer films coated with a thin layer of metal, usually aluminium. They offer a glossy metallic appearance of an aluminium foil at a reduced weight and cost. They are often used for decorative purposes and food packaging, as well as special applications such as insulation and electronics.

Outline the process of vacuum metalising.

Vacuum metalising involves heating the coating metal to its boiling point in a vacuum chamber, then letting condensation deposit the metal on the substrate's surface.

What is meant by metalising and what is its purpose?

Metalising is the general name for the technique of coating metal on the surface of objects. Metallic coatings may be decorative, protective or functional.

What is OSB and how does its structure differ from plywood?

Oriented strand board (OSB) is a wood panel manufactured from rectangular-shaped strands of wood. They differ from plywood as the strands are often oriented in a lengthwise formation, with more strength in one direction.

Describe the structure of the wood composite plywood and outline why this structure makes it such a strong material.

Plywood is a sheet material manufactured from thin layers or "plies" of wood veneer that are glued together with adjacent layers having their wood grain rotated 90 degrees to one another. The alternative of the grain (cross-graining) makes the strength of the panel consistent across all directions.

What properties does neoprene have that make it a suitable material for wetsuits?

Neoproprene is resistant to abrasian, chemicals and oils (as well as other liquids).

Why is synthetic rubber superior to natural rubber and what is it typically made from?

Synthetic rubbers are typically superior to natural rubbers as natural rubbers often contain traces of impurities and have inferior thermal stability. Synthetic rubbers are made from petroleum-based monomers.

What is meant by vulcanisation and why is its development important?

The process of vulcanisation refers to adding sulphur to rubber. This allows the elastic material to retain its moulded shape.

How is natural rubber often obtained?

Rubber is drawn from the bark of a rubber tree as a latex solution, which is then solidified into tough elasticmaterial by being heated over a smoky fire.

Whatare the characteristics of metallic foams and what applications do they have?

(Definition) A metal foam is a cellular structure consisting of a solid metal (usually aluminium) with gas-filled pores.

The defining characteristic of metal foams are their high porosity (these are ultralight materials). They are commonly used in heat exchangers and in cars.

What two forms is polyurethane foam available in and what applications do they have?

Polyurethane foams are available in two different forms either as flexible foams (for the production of sponges) or as rigid foams (used for internal reinforcement of aircraft wings and other structures).

Describe how and why styrofoam is used by designers in the development of products.

Styrofoam is very useful for block modelling and designers use it to help develop products. This is due to its high rigidity, compressive strength and it can easily be cut and shaped with normal hand tools; It is possible to sand to a high quality finish.

What is expanded polystyrene and what applications does it have?

'Expanded polystyrene' is a popular foamed or 'expanded' plastic, its volume consists 97% of air bubbles so it is an excellent flotation material. Its uses include disposable cups and food containers etc.

Outline the properties of foam which make it a useful material for manufacturing products and packaging.

Foams' lightness and compressibility make them ideal as packaging materials.

What is foam? Distinguish between open-cell foam and closed-cell foam.

A foam is formed by trapping tiny air pockets in a liquid or solid. In closed-cell foams the gas produces discrete pockets completely surrounded by solid material. In open-cell foams gas pockets connect to one another.

Why do designers need to take into account the scale of production for the products they're designing?

Designers and manufacturers have to be conscious about the scale of production required for a product as it will have an impact on decisions about the manufacturing process e.g. it would be uneconomic to create a mould meant for a bespoke product but would be beneficial to invest in a mould if thousands of a product are being produced

How would manufacturers obtain the best 'yield' from standard sheet sizes?

Thye may use software to calculate the best yield of parts from standard sheets. Software is often used to 'tessellate' patterns to minimise waste and machining required.

Describe why vacuum forming is a far less expensive process than injection moulding.

Vacuum forming is a very simple and inexpensive process, especially since moulds are often made simply from wood, resin or dense foam that can be made on a CNC router. Injection moulding has very high set up costs.

Outline one principle drawback of vacuum forming.

For vacuum forming, some post production finishing is required and there are limitations to the shapes possible to form.

Outline the advanatages of utilising injection moulding.

Injection moulding is ideal for mass production and provides components with low unit costs. Precision moulding is possible of complex shapes and a high level of surface finish is achieved.

Outline the key disadvantages of injection moulding.

There are high initial set up costs and small runs are not economic.

Name a suitable polymer for a bike frame and outline the advantages of using said polymer.

Carbon Fibre

- Very strong and light material (good strength to weight ratio),

this property is useful for a cyclist, reduces the weight of the bike.

- Resistant to corrosion, allows the bike to be used in all weather conditions and reduces the need for a weather proof coating.

- Can be formed using a mould allowing for a range of aerodynamic frame shapes.

- Good resistance to fatigue allows the frame to withstand the impacts of general road cycling.

- Provides a rigid frame which allows for the effective transfer of energy from the cyclist through the frame and wheels to the road.

What is a composite material?

A composite material is one which is manufactured from two or more materials and when combined exhibits the improved characteristics of both materials.

Describe, in detail, the process of injection moulding.

The injection moulding process is a method of forming thermoplastics using heaters, a reciprocating screw and a mould. Polymer granules are loaded into the hopper, which feeds into a heated barrel. Inside the barrel is a reciprocating screw which will transfer the polymer granules along the barrel. The action of friction and the heating elements around the barrel will cause the polymer to become plastic. Once it is plasticised it can be injected into the appropriate mould. This process will allow for a range of complex shapes to be produced quickly and in large quantities, the quality and surface finishing mean that each piece produced will need little to no finishing.

Outline three reasons why a munfacturer might choose to utilise injection moulding?

1. Speed of manufacture - 100s can be made in one go

2. High quality finish

3. Consistent product produced

Explain the advantages of using bought-in components to the manufacturer.

- Reduced manufacturing time, the manufacturer does not need to make all the components

- Improved quality control, ensures consistency for the manufacturer

- Fewer skilled staff required, manufacturer can employ staff skilled in one area of production

- Less specialist equipment needed

- Reduced storage as a result of small range of raw materials

Name a semi-permanent fixing method that could be used to join storage systems together.

Barrel nut and bolt fitting

Outline the advantages of using beech

- It is very hard and tough, an ideal material for an application used often

- It has good strength properties and is resistant to abrasian

- A straight-grained hardwood with a fine texture making it easy to work

What does the presence of a BSI kitemark on a product signify?

The product meets the required standards of the British Standards Institution (BSI).

What is the ISO 9001 and why would companies seek to gain such a validation?

The International Standards Organisation (ISO) is an international standard-setting body composed of representatives from various organisations, including BSI. The presence of a CE mark can help companies to sell a product as it passes the ISO standards (safe, reliable, good quality).

What are two principle areas covered by national standards concerning products?

1. Quality

2. Safety

What intellectual property right would provide protection for:

(a) The BMW logo

(b) The decoration on a glasses case

(c) A painting

(a) Copyright

(b) Design right

(c) Patent

Define design right.

Design right is an intellectual property right in British law that protects the shape of a three dimensional design.

Define patents.

Patents for an invention are granted by the government to the inventor to provide protection for up to 20 years.

Define copyright.

Copyright is a legal right that grantss the creator of an original work exclusive rights for its use and distribution.

What is meant by intellectual property and intellectual property rights?

Intellectual property (IP) is a category of property that includes creations of the mind. Intellectual property rights include patents, copyright, design rights, trademarks etc.

Briefly describe the following standards:

(a) IEEE standards

(b) RoHS standards

(c) Battery directive

(a) The institute of electrical and electronics engineers (standards association) creates standards for industries such as power/energy, biomedicine, robotics etc.

(b) Restriction of Hazardous Substances (directive) restrict the use of hazardous substances in electrical equipment.

(c) The Battery Directive regulates the manufacture & disposal of batteries.

What is 'Six Sigma' 5 stages?

Define the problem

Measure extent of problem

Analyse where problem

Improve/introduce procedures

Control/ensure procedures are implemented