Core 4 Flashcards

1
Q

What are physical properties?

A

Properties that can be determined without damage or destruction and relate to the interaction of the material with energy and matter in its various forms.

Mass (kg) - Mass is a measure of the amount of matter a body contains.
—–
Weight (N) - Weight is a force and represents the mass of an object acted upon by gravity.
—–
Electrical resistivity (σ) - This refers to the ease with which electrons move through a material.
—–
Thermal conductivity (W.m^-1.K^-1) - A measure of the efficiency with which thermal energy will travel through a material.
—–
Thermal expansion (m.m^-1.K^-1) - describes how the size of an object changes with a change in temperature.
—–
Hardness - The resistance of a material to scratching or abrasion. A composite of:
- Yield strength
- Work hardening
- True tensile strength
- Modulus of elasticity

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2
Q

What is hardness and the tests for hardness?

A

Test: Scratch Hardness
—–
Involves the scratching of the test surface with a stylus/indenter.
The test identifies a material’s resistance to being scratched, developed in 1812.
—–
Test: Static Indentation Hardness
—–
These tests typically involve the penetration of an indenter into the test surface using low loading rates.
—–
Test: Dynamic Hardness
—–
Rebound tests in which an indicator falls from a standard height and the change on rebound is measured.
These tests depend on elastic recovery of the test surface and use high rates of loading.

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3
Q

What are mechanical properties?

A

Properties that relate to the way in which the material responds to the application of a force.

Tensile & compressive strength - A measure of a material’s resistance to plastic deformation from a tensile or stretching type load - The ultimate tensile stress is the maximum tensile strength, this is the number that we measure for when testing this.
—–
Stiffness - The resistance of an elastic body to deflection by an applied force.
—–
Toughness - The ability of a material to resist the propagation of cracks.
—–
Fracture Toughness - Relates to the size of the crack that may be present before fracture will occur.
—–
Ductility - The ability of a material to undergo plastic deformation by extrusion or the application of tensile forces.
—–
Elasticity - A measure of a material’s ability to stretch under load and then return to its original dimensions after removal of that load.
—–
Plasticity - Elasticity of a material is associated with elongation behaviour that exceeds the elastic region.
—–
Young’s modulus - Measure of the stiffness or rigidity of a material. It describes how much a material will stretch or compress when a force is applied to it.
—–
Stress - A measure of the force being applied per unit area. (Stress = force / area)
—–
Strain - A measure of change in length occurring when under stress, divided by the unit length.
—–
*Stress and strain have true values which involve the instantaneous csa or length but more difficult to measure.

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4
Q

What are the aesthetic characteristics of materials?

A

Sweet, sour, bitter, salt, and umami.
—–
Taste: 2
—–
Human taste in a style, aesthetic, colours, etc.
—–
Hearing
—–
Different pitch, timbre, tone, clarity, volume, frequency and decay.
Certain types of sounds can invoke different types of thoughts and feelings by the brain.
—–
Smell
—–
Response to scent is largely learned with life experiences and emotions. Smells are subjectively pleasant across cultures.
—–
Appearance: colour
—–
Colours, in their different shades and vibrances, like sound, can also invoke a variety of different emotions when processed by the brain.
—–
Appearance: shape
—–
The shape, and surface can change a products appeal and vary how people view it.

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5
Q

What are the smart materials? Their properties? and the 5 smart materials learnt?

A

Materials that can respond to external stimuli or changes in their environment and exhibit specific, reversible changes in their properties.

Responsiveness, reversibility, adaptability
=====
Piezoelectricity
—–
Material that responds to an application of an applied stress by producing a small electrical discharge and vice versa.
—–
Shape memory alloys
—–
Capable of changing shape and size in a predetermined manner by undergoing a solid-state phase change.
—–
Photochromic
—–
Undergo a reversible photochemical reaction that results in darkening proportional to the level of exposure to UV light.
—–
Magnet/Electro-rheostatic
—–
Fluids that can undergo changes in their viscosity, becoming semi-solid when exposed to an electric or magnetic field
-
Low toxicity
Non-abrasive
Non-corrosive
Long storage life
Long working life
High boiling point
Low freezing point
—–
Thermoelectricity
—–
Exhibit the feature that when exposed to temperature differential, an electric potential is created and vice versa.

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6
Q

What is an ore? What are the processes surrounding them?

A

Ores can be smelted over intense heat to separate them into the impurities that make them up thanks to unique melting points.

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7
Q

Explain grain and grain size in metals.

A

The crystal structure of a metal reflects its properties.
-
As a metal solidifies, these crystals form and grow. Eventually, different crystals will collide and intersect at different angles/patterns.
This region of mismatch is known as the crystal or grain boundary.
-
Hence, grain size refers to the average size of the individual grains that make up the microstructure.

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8
Q

What are the four ways of modifying the mechanical properties of metals?

A

Alloying

elements other than those of the base metal are intentionally incorporated into the crystal lattice of the base metal. This results in the presence of more than one crystal structure.
-
Used to to gain more desirable characteristics in a metal such as improved strength, corrosion resistance, hardness, or other properties.
=====
Work hardening (cold working)
=====
strengthens a metal by deforming it through processes such as rolling, hammering, or bending, typically at room temperature.
-
introduces dislocations in the metal’s crystal structure, which makes further deformation more difficult, thereby increasing the metal’s strength and hardness.
=====
Annealing
=====
A heat treatment process that involves heating a metal to a specific temperature, holding it at that temperature, and then slowly cooling it down.
-
Reduces hardness, relieves internal stresses, and improves ductility. It also can refine the grain structure, making the material easier to work with.
=====
Tempering
=====
ferrous alloys such as stainless steel undergo a hardening heat treatment, in which an item is raised to an elevated temperature and cooled rapidly by plunging it into a suitable quenching medium.
-
Hardness and strength are significantly increased, however, there is an accompanying decrease in ductility and impact toughness.

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9
Q

What are superalloys? What criteria must they meet?

A

Feature excellent high-temperature creep resistance, resistance to thermal shock and high-temperature oxidation resistance.
These alloys are well known for their ability to operate at high temperatures while maintaining strength.
====
Creep resistance: creep is the tendency of a solid material to undergo slow deformation while subject to persistent mechanical stresses.
—–
Thermal shock resistance: ability to withstand sudden and extreme changes in temperature without cracking or failing.
—–
High-temperature oxidation resistance: ability to resist oxidation at elevated temperatures when exposed to oxygen.

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10
Q

What are the applications of superalloys?

A

Iron-nickel based superalloys
- Cryogenics
- Jet engine components
- Petrochemical processing
machinery
=====
Cobalt-based superalloys
- Turbine blades
- Orthodontic wires
- Biomedical implants
- Food processing equipment
=====
Nickel-based superalloys
- Air scrubbers
- Marine applications
- Gas turbine components

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11
Q

Discuss the recovery and disposal of metals and metallic alloys.

A

Recycled steel can be used in place of virgin iron, resulting in 60% energy savings in comparison to extracting more iron ore.
—–
Aluminium is one of the most energy-intensive materials to produce and the largest electrical energy consumer of all industries. Recycled aluminium however requires less than 6% of the mined alternative.
—–
E-waste is often shipped off to be dealt with in developing countries where it can pose major health problems if allowed to leach into the environment (lead, arsenic, mercury). It contains many expensive materials such as platinum and silver, its recovery could offer considerable cost savings.

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12
Q

Discuss the characteristics of softwood, hardwood and man-made timbers.

A

=====
Softwood
=====
- simpler structure, containing a single cell type.
- made up of long pores (Tracheids) which act as fluid transport.
- Typically conifers, have needle-like leaves and form cone seeds.
- Usually lighter in colour, found in cooler climates.
- Grow much faster due to the way nutrients are transported
- Lower densities and reduced hardness however this does not stay true for all examples.
=====
Hardwood
=====
- Made up of two cell types, fibre and vessel.
- Fibers provide strength and structural support. Tough and resistant to bending. Long and slender, interlocking.
- Higher fibers content generally means more durable the wood is.
- Vessel cells form the water-conducting system. Large and cylindrical with thin walls. Arrange end to end to form tubes.
- Broad leaves which are lost in winter. Seeds enclosed in fruits. Can be evergreen or deciduous.
=====
Man-made timbers
=====
- Composite products that use wood lengths, fibres and veneers with adhesive binder, combined under heat and pressure.

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13
Q

Give examples of hardwoods, softwoods and man-made timbers.

A

HW: Oak, mahogany, beech, walnut, balsa.
SW: Pine, cedar, spruce, redwood.
MMT: Plywood, MDF, chipboard, LVL

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14
Q

What unique characteristics do MMTs exhibit?

A

Uniformity of properties, its properties stay true regardless of environment.
-
Greater availability of product sizes and shapes.
-
Lower cost compared with solid natural timbers of the same dimensions.

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15
Q

What factors affect the strength of timbers

A

Duration of loading: a decrease in strength due to extensive load
-
Defects: knots, splits, shakes etc - disrupt grain flow
-
Chemical treatment: adverse effect on mechanical properties
especially water-based preservatives

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16
Q

Explain seasoning and why it is used.

A

Moisture must be removed before use without causing splitting or warping.
-
If moisture is below 20%, timber will decay.
-
Seasoning can be done by air or by kiln.
=====
Air seasoning
=====
Stacked in a way that allows air circulation on all sides
Shield the timber from rain but allow air to flow freely
-
Several months, slow
-
Low-cost, low energy use, environmentally friendly
=====
Kiln seasoning
=====
Stacked in a kiln where air circulation, temperature, and humidity can be precisely managed.
Begins with lower temperatures and higher humidity, which are gradually adjusted to avoid rapid drying that might cause cracking or warping.
-
Days or weeks, fast, quality control
-
Higher cost and energy use.
=====
Correctly seasoned timber is:
- Strong
- Stable
- Resistant to decay
- Easy to paint, glue, nail, screw and machine.

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17
Q

What processes are involved with finishing timbers?

A

Treatment

can involve solutions which make the wood poisonous to insects, fungus, and marine borers as well as protecting it from the weather.
-
generally, timbers which are to be positioned outside should make use of a treatment.
=====
Finishing
=====
Finished timber requires sanding and one of the following:
- Stain
- Paint
- Shellac
- Wax polish
- French polish
- Plastic varnish

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18
Q

Explain what the different finishes do.

A
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19
Q

Discuss deforestation and reforestation.

A

The timber industry is a big part of the reason for deforestation.
-

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20
Q

Discuss glass. What are its characteristics?

A

This sort of glass is relatively soft. To give the glass stability and hardness, materials such as limestone and dolomite are added. Scrap glass can also be added to make the process more economical.
-
The main types of glass are glass fibre, lead glass, soda-lime glass, and borosilicate glass.
=====
- Transparency
- Chemically Inert
- Non-toxic
- Hardness
- Brittle
- Aesthetic Versatility
- Electrical Insulator
- Cheap

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21
Q

What are the applications of glass? Link to its characteristics.

A

Fibre optic cables
Food and chemical containers
Containment of nuclear waste (Vitrification)
Protective layer in solar cells
Cookware and lab equipment
Scratch-resistant glass in displays
Decorative glassware

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22
Q

Discuss the recovery and disposal of glass.

A

When collected for recycling, glass is separated by colour, crushed, and remelted for use in new glass containers.
-
Environmental benefits of reducing quarrying and reduced energy usage as cullet melts easier.
-
Cullet needs to be in the right condition to be used, i.e. free from impurities.

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23
Q

What is the structural difference between thermoplastics and thermosetting plastics?

A

Thermoplastics: Linear or Branched Polymer Chains

long, linear or branched polymer chains. Weak intermolecular forces hold these chains together without chemical bonding between them.
-
weak forces between chains allow the chains to move past each other easily when heated, so they can be repeatedly melted and reshaped.
-
When the material cools, these chains return to a solid form without altering the chemical structure, allowing thermoplastics to be re-molded multiple times.
-
Examples: Polyethylene (PE), Polypropylene (PP), and Polyvinyl Chloride (PVC).
=====
Thermosetting Plastics: Cross-Linked Polymer Network
=====
Cross-linked, three-dimensional network of polymer chains. Curing, these chains form covalent bonds between them, creating a rigid structure.
-
Highly stable and resists movement, making thermosetting plastics hard and rigid.
-
Structure is permanent and cannot be reshaped by heating; if heated further, thermosets will decompose rather than melt.
-
Structure provides high resistance to heat, chemicals, and wear.
-
Examples: Epoxy resin, Bakelite, Melamine, and Phenolic resin.

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24
Q

What is curing?

A

When a thermosetting plastic or resin, undergoes a chemical reaction that hardens and sets it into a permanent, rigid structure. This reaction typically involves heat, light, or a chemical additive and creates cross-links between polymer chains, making the material strong, durable, and heat-resistant.

25
Q

Discuss the difference in physical properties between thermoplastics and thermosetting plastics.

A

Flex: TSP are rigid and inflexible after setting. TP can be bent and shaped.
-
Hardness: TSP is hard and durable, TP is typically softer.
-
Heat R: TP have limited heat r, TSP have excellent heat r after curing.
-
Chem R: TSP have high chem r.
-
Elasticity: TSP is brittle once cured. TP is elastic and flexible.
-
Dimensional Stability: TP can warp or deform under heat. TSP holds shape under high-temp well.

26
Q

Discuss the disposal and recovery of plastic.

A

Pollution in the natural environment damages ecology.
-
Recycling of plastic is possible with correct sorting.
-
A wide variety of plastics makes recycling difficult.
-
Impurities in plastics as “filler” also doesn’t help.
-
Incineration releases toxic by-products.

27
Q

What are the raw materials used in textiles?

A

Natural fibres originate either from plants or animals such as cotton, linen, wool and silk.
-
Synthetic fibres are man-made by chemical processes. Many are polymer-based originating from oil or coal. Others are manufactured from glass, metal ceramic and carbon.

28
Q

What are the properties of natural fibres with examples?

A

Cotton - cotton plant sourced

Soft, breathable, and highly absorbent; durable but wrinkles easily; commonly used for clothing and home textiles.
=====
Wool - sheep sourced
=====
Excellent insulator with good elasticity; naturally resistant to wrinkles; ideal for warm clothing and blankets.
=====
Linen - flax plant sourced
=====
Crisp, strong, and highly breathable; has a natural sheen; tends to wrinkle easily; often used in warm-weather garments and table linens.
=====
Silk - animal sourced (spider)
=====
Luxurious, smooth, and lustrous; strong yet delicate; has moderate absorbency; commonly used for high-end clothing and accessories.

29
Q

What are the properties of synthetic fibres with examples?

A

Nylon - petroleum

Strong and abrasion-resistant; smooth and lightweight; low absorbency; commonly used in activewear, hosiery, and outdoor gear.
=====
Polyester - derived from petroleum-based polymers
=====
Highly durable and wrinkle-resistant; dries quickly; low absorbency; widely used in clothing, home furnishings, and outdoor products.
=====
Acrylic - derived from polyacrylonitrile
=====
Soft and warm, mimicking wool; lightweight and durable; low absorbency; often used for sweaters, blankets, and outdoor textiles.
=====
Lycra (Spandex) - polyurethane-based
=====
Exceptionally elastic and stretchable; maintains shape and fit; low moisture absorbency; ideal for sportswear, swimwear, and form-fitting garments.

30
Q

How are fibres converted into yarn?

A

Fiber Preparation:

Cleaning: Raw fibres are cleaned to remove dirt, grease, and impurities.
-
Carding: The fibres are carded to disentangle and align them, creating a web of loose fibres.
=====
Drawing:
=====
The carded fibres are drawn into long, thin strands. This step involves pulling and stretching the fibres to align them further and reduce thickness.
=====
Spinning:
=====
The drawn fibres are twisted together to form yarn. This is done using a spinning wheel or machine, which applies tension and twists to the fibres, turning them into a cohesive strand.
=====
Plying:
=====
In some cases, two or more strands of yarn are twisted together (plied) to create a thicker, stronger yarn. Plying adds texture and durability.
=====
Finishing:
=====
The yarn may undergo various finishing processes, such as washing, setting the twist, or applying treatments to enhance its properties (e.g., softness, color).

31
Q

What processes are used in turning yarn into fabrics?

A

Knitting (Yarn)

Interlocking loops of yarn to create fabric using two needles (or a knitting machine). Each row of stitches is formed by pulling new loops through existing ones, allowing for a wide variety of patterns and textures. Knitting is versatile and can be done by hand or machine, producing stretchy, comfortable fabrics.
-
Sweaters, scarves, hats, blankets, and other garments; also used in accessories like mittens and socks.
=====
Weaving (Yarn or thread)
=====
The process of interlacing two sets of yarn, known as the warp (vertical threads) and the weft (horizontal threads), on a loom. This technique can create intricate patterns and textures, and the density and style can vary greatly depending on the type of weave (e.g., plain, twill, or satin). Weaving is foundational in textile production.
-
Tapestry, fabrics for clothing, carpets, upholstery, and industrial textiles; also used for decorative wall hangings.
=====
Lace-Making (Fine thread)
=====
knotting or weaving fine threads, often resulting in openwork designs. This technique can involve various methods such as needle lace, bobbin lace, or crochet. Lace-making is an art form that requires precision and skill, allowing for delicate and decorative results.
-
Lace fabrics, trims for garments, doilies, tablecloths, and decorative items such as curtains or shawls.
=====
Felting (Wool fibres or pre-felted materials)
=====
A textile-making process that involves matting and compressing fibres (usually wool) through moisture, heat, and agitation. The scales on wool fibres interlock, creating a dense, sturdy fabric. Felting can be done wet or dry (needle felting) and allows for creative shaping and sculpting. Felting is often used in crafts and artisan products.
-
Felted items such as bags, hats, rugs, toys (e.g., felted animals), and art pieces; are also used for insulation and padding.

32
Q

Discuss the recovery and disposal of yarn.

A

Disposal, on the other hand, poses challenges. Traditional synthetic yarns, like polyester and nylon, can take hundreds of years to decompose, contributing to landfill waste. To combat this, the industry is exploring biodegradable alternatives and encouraging the use of natural fibres that break down more easily.
-
Moreover, there is a growing market for second-hand yarn and fabric, fostering a culture of reuse. Many artisans and craftspeople now focus on using scrap yarn to create unique items, minimizing waste. In summary, the recovery and disposal of yarn in a contemporary context emphasize sustainability, promoting recycling and reducing the environmental impact of textile waste.

33
Q

What is a composite?

A

A class of material whose properties derive from the combination of two or more materials that are bonded together for desired qualities.

34
Q

What types of composites are there?

A

Fiber-Reinforced Composites:

Use fibers to improve strength, stiffness, and durability.
-
Glass Fiber Reinforced Polymer (GFRP): Lightweight, strong, and corrosion-resistant; used in automotive and aerospace applications.
-
Carbon Fiber Reinforced Polymer (CFRP): Offers high strength-to-weight ratio; commonly used in high-performance applications like sports equipment and aerospace.
-
Fibreglass, Kevlar, Carbon-reinforced plastic
=====
Particle-Reinforced Composites
=====
Matrix material with particles embedded to enhance properties like strength, toughness, and thermal stability.
-
Concrete: Aggregates (sand, gravel) mixed with cement; used in construction.
-
Metal Matrix Composites (MMCs): Metal matrix reinforced with ceramic or metal particles; used in aerospace and automotive applications for improved mechanical properties.
-
Particleboard
=====
Layered Composites
=====
Multiple layers of different materials bonded together, each contributing specific properties.
-
Plywood: Layers of wood veneer glued together; used in furniture and construction for structural applications.
-
Laminates: Composite materials like laminate flooring or countertops, typically made from resin-impregnated fibres.
-
Glue laminated timber, Laminated veneer lumber, parallel strand lumber.

35
Q

What processes are involved in making composite materials?

A

Weaving

Interlacing two sets of yarns or fibres (warp and weft) to create a textile structure. Woven fabrics provide flexibility and strength and are often combined with resins to form fibre-reinforced composites.
-
Carbon fibre panels, fabric composites, tapes.
=====
Lay-up moulding
=====
Involves manually laying fibres (e.g., glass, carbon) in a mould, and then applying resin over the layers. This method can be open (hand lay-up) or closed (vacuum bagging) and is cost-effective for low-volume production.
-
Boat hulls, panels, large structures
=====
Resin Transfer Moulding (RTM)
=====
Uses a closed mould to inject resin into dry fibre reinforcements. This process creates high-strength composites with consistent quality and allows for complex shapes.
-
Automotive parts, aerospace components, sporting goods
=====
Pultrusion
=====
Continuous process where fibres are pulled through a resin bath, then shaped and cured by heating in a mould. Pultrusion produces uniform, long profiles with high strength.
-
Beams, structural components, window frames
=====
Lamination
=====
Layering thin sheets or veneers of material, often wood, with adhesive, then compressing them under heat or pressure to form a single, strong piece. This process improves durability and dimensional stability.
-
Plywood, glulam beams, laminated countertops

36
Q

Discuss the composition of concrete.

A
37
Q

Discuss the composition of plywood.

A
38
Q

Discuss the composition of fibre-glass

A
39
Q

Discuss the composition of particle board.

A
40
Q

Discuss the composition of kevla=r.

A
41
Q

Discuss the composition of carbon-reinforced plastic.

A
42
Q

Discuss the composition of glued laminated timber.

A
43
Q

Discuss the composition of Laminated veneer lumber.

A
44
Q

Discuss the composition of parallel strand lumber.

A
45
Q

What are the different scales of production?

A

One-off production

Producing a single, unique product to specific requirements.
-
Highly customizable, high cost per unit, labour-intensive.
-
Custom furniture, bespoke clothing, prototypes.
=====
Batch Production
=====
Producing a set quantity of a product in a limited production run, allowing for some customization between batches.
-
Moderate customization, lower costs per unit than one-off, flexible for seasonal demand.
-
Baked goods, small-run electronics, seasonal products.
=====
Continuous Production
=====
Ongoing production of a product without interruptions, often 24/7, to meet steady demand for high-volume items.
-
Minimal customization, high efficiency, low per-unit cost, high initial setup.
-
Chemicals, energy, food products (e.g., flour milling).
=====
Mass Production
=====
Large-scale production of standardized products, usually in assembly lines, to meet high demand at low costs per unit.
-
Limited or no customization, low cost per unit, automated processes
-
Automobiles, household goods, consumer electronics.

46
Q

What do economies of scale refer to?

A

Mass production of consumer electronics or furniture, economies of scale allow manufacturers to reduce the costs of materials, distribution, and machinery per unit.

47
Q

What are the 4 groups of additive techniques?

A

Create objects by building them up layer by layer

Lamination
Laminated object manufacturing
=====
Stacking and bonding layers of material, often paper, plastic, or metal sheets, to create a 3D object. Each layer is precisely cut (usually with a laser) to match the design’s cross-section, and layers are bonded by heat or adhesive.
-
Creating sturdy prototypes or large models, often used in architecture or industrial design.
=====
Photopolymers
Stereolithography
=====
Use liquid resin that solidifies when exposed to a UV light source. A laser or projector cures each layer, and the process repeats until the object is complete. The cured resin layers fuse to create highly detailed and smooth objects.
-
Creating highly detailed models, jewellery prototypes, medical devices, and intricate design prototypes.
=====
Deposition
Fused deposition modelling
=====
Use materials (often thermoplastics) that are heated to a semi-liquid state and extruded layer by layer to build up a part. The process involves a nozzle that moves in horizontal and vertical directions to deposit the material according to the object’s design.
-
Prototyping, consumer products, automotive parts, and low-volume manufacturing due to its versatility and accessibility.
=====
Powders
Selective laser sintering
=====
Spreading a thin layer of powdered material (e.g., plastic, metal, or ceramic) and using a laser or binder to fuse particles selectively. Each layer is sintered or bonded, creating strong parts that can withstand stress.
-
functional prototypes, complex geometries, aerospace components, and medical implants due to the strength and durability of the final parts.

48
Q

What are the 4 groups of additive techniques?

A

Remove material from a solid block

Mechanical cutting, abrasive cutting, thermal processes, electrical charge.
=====
Abrasive water-jet cutting
=====
Directing a thin stream of water with fine abrasive particles through a nozzle at ultra-high pressures to cut a wide variety of materials.
-
Rubber, paper, stone, leather, plastics, metals.
=====
Oxy-acetylene (Thermal process)
=====
Supply of acetylene and oxygen from separate pressurised containers via rubber hoses to a cutting torch where gasses are mixed to produce a flame at 3,500C.
-
Used in steel due to its portability and versatility.
-
Flashback arrestor installed to prevent explosive decomposition.
=====
Plasma cutting (thermal)
=====
Ionisation of high-velocity gas stream to form a plasma of ~25,000
C, commonly compressed air.
-
Cut material needs to conduct electricity, metals only.
=====
Laser cutting
=====
High-power laser directed to flat sheet surfaces. Allows for high-quality surface finish thanks to vaporisation of material.
-
Computer can be used if production is repetitive, complex or long.
=====
Machining (mechanical cutting)
=====
Where a cutting tool moves across a workpiece to remove material from the surface.
-
The process is expensive as requires skilled workers or technicians to monitor automated operations.
=====
Turning (mechanical)
=====
Performed on a lathe where material is rotated at high speed as a cutting tool is moved along the surface.
=====
Milling (mechanical)
=====
Rotating cutting head, around which a number of cutting inserts are fitted. Cutting bed moves through cutting area.
=====
Abrading
=====
Physical wearing away of surfaces through rubbing, friction or erosion. Harder materials are more resistant to abrasion.
-
Abrasives can be rigid tools, suspended in liquid, water jets, carried by a jet of compressed air.

49
Q

What are the moulding shaping techniques?

A

Injection Moulding

Molten plastic is injected into a mould cavity, where it cools and solidifies to form the desired shape.
=====
Resin Transfer Moulding (RTM)
=====
Dry fibre reinforcements are placed in a closed mould, and resin is injected under pressure, saturating the fibres to create a strong composite.
=====
Blow Moulding
=====
A process where air is used to expand a molten tube of plastic (parison) into a mould, forming hollow objects.
=====
Extrusion Blow Moulding
====
Similar to blow moulding, but the parison is created by extruding plastic through a die, then blown into shape inside the mould.
=====
Injection Blow Moulding
=====
Combines injection and blow moulding; a preform is injection-moulded and then blown into the final shape in a second step.
=====
Stretch Blow Moulding
=====
Similar to injection blow moulding, but the preform is stretched axially during blowing to improve clarity and strength, often used with PET.

50
Q

What are the casting shaping techniques?

A

Pressure Die-Casting

Molten metal is injected into a mould under high pressure, allowing for the production of intricate shapes with smooth finishes.
-
Commonly used for aluminium and zinc parts in automotive and consumer products.
=====
Sand Casting
=====
A pattern is made in a sand mould, into which molten metal is poured. The sand allows for flexibility and easy pattern removal, making it suitable for larger, simpler parts.
-
Used for engine blocks, pipes, and other large components in various industries.
=====
Precision Casting
=====
Also known as investment casting, this technique involves creating a wax pattern coated with a ceramic shell. The wax is melted away, leaving a precise mould for pouring metal.
-
Ideal for complex shapes and tight tolerances, commonly used in aerospace, jewellery, and medical device manufacturing.

51
Q

Describe laminating, knitting and weaving.

A

Laminating - a permanent bonding process were improved properties can be obtained.
Knitting - A single thread is looped to form an interlocking construction that produced a flexible fabric. (Oil and air filters, mufflers, silencers, heat transfer, insulation, metal alloy compression strings.
Weaving - Passing fibres of material under and over each other in an interlacing fashion.

52
Q

What are some permanent joining techniques?

A

Adhering

Involves bonding materials together using adhesives. This can include various types of glue or epoxy that cure to create a strong bond between surfaces.
-
Used in wood, plastics, metals, and composites; common in furniture, automotive, and construction applications.
=====
Fusing (Welding)
=====
Involves melting and joining materials, typically thermoplastics or metals, using heat. This can include processes like welding and soldering.
-
Commonly used in metal fabrication, piping, and joining thermoplastics in packaging and industrial products.

53
Q

What are some temporary joining techniques?

A

Riveting

A mechanical fastening process where a metal pin (rivet) is inserted into aligned holes and deformed on one or both ends to secure the materials together.
-
Commonly used in structural applications, aircraft, and bridges due to its strength and durability.
=====
Screws
=====
A threaded fastener that is driven into materials, providing a secure hold. They can be easily removed and reused.
-
Used in woodworking, metalworking, and construction for securing components.
=====
Nails
=====
A small, slender metal pin that is driven into materials, usually with a hammer. Nails provide a quick, temporary hold but can be removed with difficulty.
-
Commonly used in framing, carpentry, and roofing applications.
=====
Bolts
=====
A type of fastener that consists of a head and a threaded shaft, requiring a nut to secure materials together. Bolts can be easily disassembled and reused.
-
Widely used in construction, machinery, and automotive applications where strong connections are required.

54
Q

What is craft production, mechanised production, automated production, numerical control, assembly line production, and mass customisation?

A

Craft production

production of a single unique product. Involves manual skills where skills determines quality of one-off pieces.
=====
Mechanised production
=====
the introduction of machinery into a proces with the intern of automating the process to some degree. In simplest form, replacing hand crafting operations.
=====
Automated production
=====
the replacement of human labour with mechanical, electronic or computer controlled machinery processes and systems that operate automatically.
=====
Numeric control
=====
the automation of machining operations using programmed commands as opposed to mechanical inputs such as hand-wheel, levers or cams. NC machines receive instructions as data, not connected to computer.
=====
Assembly line production
=====
the movement of a product to be manufactured from station to station, often with conveyor belts or other transportation systems.
-
Production line workers were typically involved with simple, repetitive tasks that have no association with the production of a final product. Mechanisation largely reduced the labour needed.
=====
Mass customisation
=====
flexible manufacturing systems to bring efficiencies of mass production to short job runs even down to single orders. Allows manufacturers to meet consumer demands from computers in their homes. E.g. trainers.

55
Q

What is CNC?

A

Computer numeric control systems allow an operator to generate a computer file of instructions that can be directly loaded into the CNC machine for manufacturing. CNC uses a computer control unit that calculates optimal settings and issues commands accordingly in the form of numer data to motors that position slides, select tools, adjust spindle speeds, manipulate tool paths and control coolant.

56
Q

What is design for manufacturing? (DfM)

A

An engineering practice that focuses on simplifying and optimizing a product’s design to improve its manufacturability. The goal is to reduce production costs and time while enhancing product quality.

Principles
=====
Simplicity,
Standardisation,
Minimising assembly,
Material selection,
Tolerance.
=====
Reduced production costs and time.
-
Enhanced product quality and reliability.
-
Streamlined manufacturing processes.

57
Q

Discuss what a robot is and what they are used for.

A

It can be defined as an “actuated mechanism programmable in two or more axes with a degree of autonomy, moving within its environment, to perform intended tasks”.
-
They can be used in industry, service, personal care, medicine, quality control, inventory, fabrication, assembly operations, materials handling and transportation, fabrication, assembly, and material handling.

58
Q

What types of robots exist in manufacturing?

A

Single-task robots

Robots designed to perform a specific, singular task.
-Commonly used in production lines for repetitive tasks, such as assembly, welding, or painting.
=====
Multi-task robots
=====
Robots capable of performing multiple functions or tasks, often equipped with interchangeable tools or attachments.
-
Used in versatile applications, such as assembly lines where different tasks are performed by the same robot by scheduling or in parallel.
=====
Teams of robots
=====
Groups of robots working collaboratively to complete complex tasks, often communicating and coordinating with each other.
-
Enhance efficiency and productivity in large-scale operations, such as manufacturing, logistics, or warehouse management.
=====
Machine to machine
=====
Direct communication between devices or machines over wired or wireless networks without human intervention.
-
Enables automation and data exchange for monitoring, controlling, and optimizing industrial processes and systems.