1
Q
What are the issues with the pharmaceutical industry?
A
Issues with batch production in pharma
- Batch is very versatile but extremely slow and not very precise.
- There is approximately a 2- year timeframe from the start to the end of the process development (primary manufacturing part only).
- This approach requires capital intensive investment very early in product development to allow the running of clinical studies.
- This same process needs to be able to ramp up to full production.
- Therefore very high cost associated with failure.
- The batch approach is also not very agile to deploy around the world and leads to centralised manufacturing, whereas local production and distributed manufacturing may be important for future cost reduction.
- In batch manufacturing, it is difficult to reconfigure or change the design and this again adds to the cost of the products.
From lectures
- A large % of products in different phases fail, but clinic must be supplied for years and plan for success
- If launched, typically market is supplied for 10 years
- Demand volume is uncertain
- Once patent has expired, product volumes are likely to fall
- Orders must always be fulfilled
- Must manufacture to strict codes
It’s hard to plan
- If product fails, equipment can be reused
- But it is labour intensive and slow in making the product
2
Q
What is the solution to the problems in the pharmaceutical industry?
A
Try to be agile instead:
- Repurposed or negligible cost or time to change
- Precise
- Fast to supply
- Low labour
3 ideas:
- Modularisation
- System is deconstructed into more independent units (modules)
- Useful for reducing the complexity of the system
- Leads to
- Replication, mobility, standardisation means
- Increased speed in delivery and lower cost
- Digitalisation
- Leads to:
- Faster connected, reduction of downtime due to automation
- Data for predictive modelling
- Maintenance, how to do a task, deep learning, automating design
- Leads to:
- Process intensificationusing continuous manufacture
- Footprint is smaller for same output
- Leads to small precise plant
- Continuous processing is a technology that provides, small precise replicatable production.
One approach
- Substituting a number of the batch steps with a continuous process.
- The approach requires the design of a modular continuous manufacturing plant.
- This building-block approach allows
- reconfiguration, agility to deploy, agility to re-usein other processes if the product fails,
- benefit of the precision and higher levels of automation achieved in continuous manufacturing and
- the ability to build closer to the point of distribution rather than have large centralised manufacturing sites.
- Each module is a unit operation and savings will be realised even by replacing a sequence of a few of the batch steps.
It may be noted that pharmaceutical companies are risk averse about moving the entire process to continuous manufacturing because of the challenge of controlling crystallisation and the significant knowledge currently in place that surrounds batch processing in this field.
3
Q
Give some facts oil and gas in the UK
A
- Oil and gas provides more than 75% of UK’s total primary energy
- By 2035 will still be 66%
- Electricity, transportation and heating account for roughly one third of the UK’s primary energy demand, with oil for transport and gas for heating dominating these markets.
- Natural gas is the cleanest of all fossil fuels, burning nearly twice as efficiency as coal and producing much less CO2 per unit of energy
4
Q
What are the different production fluids (oil, gas, etc.)?
A
Different production fluids
- Crude oil is a mixture of 200 or more organic compounds, mostly hydrocarbons. Graded according to API number (higher API = lighter, thinner crude)
- Natural gas as used by consumers is almost entirely methane. Wellhead gas requires significant additional processing to meet transportation pipeline specifications.
- Condensates or natural gas liquids associated with natural gas are a valuable by product. They are widely used as raw materials for oil refineries and petrochemical plants.
5
Q
Describe the process of oil production from wellhead to to export?
A
Production facilities can vary from onshore wells to offshore floating wells.
Process from production wellheads to export:
- Production well head
- Production separators:
- Separate water, crude oil and natural gas
- Gas
- Compressed
- Gas meter
- Pig launcher
- Gas pipeline
- Oil
- Storage
- Crude pump
- Oil meter
- Pig launcher
- Oil pipeline
6
Q
Describe the production well head
A
Production well head
- Assembly of valves, spools, pressure gauges and chokes to control production
- Sits on top of the oil/gas well, leading down to the reservoir
- Dry completions are either onshore or on the deck of an offshore structure
- Wet completions are subsea, below the surface
7
Q
Describe production separators
A
Production separators:
- Most wells give a combination of gas, oil and water that must be separated
- Gravity separation: well flow is fed into a horizontal vessel
- Residence time is typically 5 minutes, allowing the gas to bubble out, water to settle at bottom and oil to be taken out in the middle
- Pressure is often reduced in several stages (high pressure separator, low pressure separator etc.)
- Horizontal separators:
- large liquid handling capacity
- Sufficient time for settle out of liquid droplets from the gas
- Vertical separators (scrubbers)
- High gas volumes
- Small footprint area
8
Q
Describe gas compression
A
Compression
- Gas from separators has lost so much pressure that it must be recompressed to be transported
- Turbine compressors gain energy by using a small proportion of natural gas that they compress
- Turbine operates a centrifugal compressor, which contains a type of fan that compresses and pumps the natural gas
- Compression system includes a large “train” of associated equipment such as scrubbers (removing liquid droplets) and heat exchanges, lube oil treatment etc.
9
Q
Describe the different types of heat exchangers
A
Heat exchanger needed after to remove heatShell and tube heat exchangers
- Consists of a bundle of tubes enclosed in a cylindrical shell. The ends of the tubes are fitted into tube sheets, which separate the shell side and tube side fluids. Baffles provided to direct the fluid flow and support tubes.
- Can be heavy and space consuming
- Suitable for high pressure operation
- Robust designs with long operational history
Plate heat exchangers
- Series of corrugated, pressed metal plates clamped together
- Offshore the use of plate heat exchanges has become universal due to compact size and low weight.
- Oil cooling prior to storage or pipeline export and some low-pressure gas duties.
Printed circuit heat exchangers
- Constructed from flat metal plates with chemically milled fluid flow channels.
- High heat transfer surface densities
- Suitable for high pressure applications and wide temp range
- Compact design leading to substantial weight and space savings
- Low maintenance due to corrosion resistant materials and all welded construction
Air cooled heat exchangers
- Where cooling water is too costly.
- Multiple calculations are required to produce an optimum design considering air flow rate, tube design, fin types etc.
10
Q
What are oil terminals and their functions?
What are gas terminals and their functions?
A
Oil: processed onshore rather than offshore as it is easier.
Oil terminals are intermediate oil gathering and distribution stations between offshore oil production locations and onshore oil processing facilities (refineries).
Basic functions:
- Reception of crude oil
- Stabilisation of crude oil (dehydration/desalting, gas/water treatment)
- Fractionation of associated gas into propane and butane
- Storage of stabilised crude, LPG
- Export/ shipment of products into tankers for distribution to refineries
Gas terminals:
- Function of the terminal is to process the raw gas to provide sales quality gas and liquid hydrocarbon by products.
- Gas arrives onshore at around 3 degrees.
- Internal cleaning and inspection of the pipeline is done with pigs (dirt/debris/wax/scale removed)
- Inlet gas receiver catches slugs of liquid from the pipeline
11
Q
What is the detailed process from wellhead to production of oil and gas
A
Process from production wellheads to export:
Production well head
- Assembly of valves, spools, pressure gauges and chokes to control production
- Sits on top of the oil/gas well, leading down to the reservoir
- Dry completions are either onshore or on the deck of an offshore structure
- Wet completions are subsea, below the surface
Production separators:
- Most wells give a combination of gas, oil and water that must be separated
- Gravity separation: well flow is fed into a horizontal vessel
- Residence time is typically 5 minutes, allowing the gas to bubble out, water to settle at bottom and oil to be taken out in the middle
- Pressure is often reduced in several stages (high pressure separator, low pressure separator etc.)
- Horizontal separators:
- large liquid handling capacity
- Sufficient time for settle out of liquid droplets from the gas
- Vertical separators (scrubbers)
- High gas volumes
- Small footprint area
Gas Compression
- Gas from separators has lost so much pressure that it must be recompressed to be transported
- Turbine compressors gain energy by using a small proportion of natural gas that they compress
- Turbine operates a centrifugal compressor, which contains a type of fan that compresses and pumps the natural gas
- Compression system includes a large “train” of associated equipment such as scrubbers (removing liquid droplets) and heat exchanges, lube oil treatment etc.
Heat exchanger needed after to remove heat
- Shell and tube heat exchangers
- Consists of a bundle of tubes enclosed in a cylindrical shell. The ends of the tubes are fitted into tube sheets, which separate the shell side and tube side fluids. Baffles provided to direct the fluid flow and support tubes.
- Can be heavy and space consuming
- Suitable for high pressure operation
- Robust designs with long operational history
- Plate heat exchangers
- Series of corrugated, pressed metal plates clamped together
- Offshore the use of plate heat exchanges has become universal due to compact size and low weight.
- Oil cooling prior to storage or pipeline export and some low-pressure gas duties.
- Printed circuit heat exchangers
- Constructed from flat metal plates with chemically milled fluid flow channels.
- High heat transfer surface densities
- Suitable for high pressure applications and wide temp range
- Compact design leading to substantial weight and space savings
- Low maintenance due to corrosion resistant materials and all welded construction
Gas meter
Pig launcher
Gas pipeline
Oil: processed onshore rather than offshore. Onshore processing plants called terminals.
Storage
Crude pump
Oil meter
Pig launcher
Oil pipeline
12
Q
How is a superconducting magnet made?
A
How to make a superconducting magnet
Wind coils
- 20-50 km wire per magnet
- Wire costs approx. $1/m
- Coil diameters between 1.5-2m
- Coil weights 20-980 kg
Pot coils in epoxy resin
Assemble coils
Check homogeneity at RT
Joint magnet (joints must have resistance <10^-11 ohms@ 4K)
- Pair up leads to cancel forces
- Dissolve copper matrix with conc. Acid
Fit magnet to cryostat (heat transfer to be <1W)
Pressure test cryostat
Chill magnet to 4K using 3,000-5,000 litres of liquid He
Run magnet to field (460-700A DC @10V)
Test magnet and cryostat
Ship magnet (if shipped cold ‘time to dry’ is 20-28 days)
13
Q
What are the common failure modes for superconducting magnets?
A
Quench:
- wire stops superconducting, becomes resistive and 1000 litres of liquid He suddenly boil away
Electrical short
Homogeneity
- Lack of either intrinsic or induced by site factors
Decay
- Full field not maintained between service intervals – maximum loss allowed is 0.1ppm/hr
Boil off problems
- Cryostat performance poor – system will require frequent topping up of liquid helium
- Poor vacuum (leak)
- Thermal short
- Poor connection to refrigeration
14
Q
What are the safety hazards in superconducting magnets?
What are the new trends in superconducting magnets?
A
What are the safety hazards:
- Strong magnetic fields
- Extreme cold
- Large heavy magnets
- Strong acids – HF and HNO3
What are the new trends:
- Minimum He system/ ‘dry’ system
- Higher fields
- Warm superconductors
- Cheaper systems: suitable for unsophisticated/low tech environments
15
Q
Explain the puttick grid? Explain the different aspects the puttick grid drives?
A
Puttick grid
The way a product is manufactured should be governed by:
- Production volume and market uncertainty
- Intrinsic product complexity (including variety)
These aspects drive all relevant parameters:
- Product design & material choice
- Production methods, tooling and equipment choice
- Degree of automation
- Degree of integration
- Location, logistics and distribution
- Assembly configuration choices
- People and organisation
- Production control systems
16
Q
What are the factors influencing the type of and extent of automation
A
- Product volume and variety
- Expected product life span
- Market uncertainty
- Process novelty
- Component/task variability
- Precision, cleanliness, quality, regulatory etc.
- Component complexity
17
Q
What are the different assembly system configurations?
A
What are the different assembly system configurations?
- Manual: people do the job
- Mechanised: machines help people do the job
- Hard automated: machines do job (same every time)
- Turntable
- Indexing: where different elements of production are at different rotation locations
- Constant velocity: bottle production
- Track
- Pallet based. Asynchronous
- Indexing/synchronous: cars production
- Turntable
- Flexibly automated: robots and other software driven machines do job (can be different)
- Based on off the shelf robots: SCARA, anthropomorphic, cartesian, delta etc.
- Custom multiaxis
18
Q
What are the examples of the necessary supporting processes and infrastructures?
How much software does an automation system need?
A
What are the examples of the necessary supporting processes and infrastructures?
- Packaging and feeding
- Order retained: bandoliers, tubes
- Order re-gained: bowl feeders, centrifugal feeds
- Sensory systems: proximity imaging, gauging
- Actuators: pneumatic, hydraulic, servo electric, solenoid
- Conveyors, turntables, x-y tables
- Proprietary operating systems and programming languages
- Message: exploit what’s out there and don’t reinvent the wheel
19
Q
Why is injection moulding used for manufacturing?
A
Leading process for manufacturing of plastic products: high volume, identical product
Cost:
- High tooling cost depending on complexity and number of cavities
- Low unit cost
Typical application
- Automotive
- Consumer electronics
- Appliances
- Industrial products
- Household products
Suitability:
- High volume mass production
Quality
- Very high surface finish
- High repeatable process
Related processes
- Reaction injection moulding
- Thermoforming
- Vacuum casting
Speed
- Cycles between 30 and 60 secs
20
Q
How does an injection moulding machine work?
A
How does an injection moulding machine look and work?
- Clamping
- Injection
- Cooling
- Ejection
- Plastic granules loaded into hopper
- The screw within a heated barrel forcing the polymer towards the nozzle.
- The clamping of the mould cavity and the mould.
- The injection of the molten polymer (details about runners and shot)
- The cooling of the mould
- The ejection of the component (ejection pins)
- The final removal of the sprue
- Recycling of waste back into the process
21
Q
Give examples of potential defects that can occur in injection moulded parts.
Which of these issues can CAD solve?
A
Give examples of potential defects that can occur in injection moulded parts
- Short shot
- Humidity
- Drying used pre process
- Contamination by other coloured granules
- Sink marks or Voids:
- Depressions on one side of a component due to the thicker section or a large feature on the other side. These thicker areas shrink upon cooling to give the depression. The cooling time needs to be sufficient to allow cooling in the mould.
- Knit lines and Weld lines:
- This appears as a discoloured line, where molten plastics meet as they flow from different parts of the mould. The flow fronts do not bond correctly, most often due to partial solidification.
- Warping
- A deformation or bending where there is uneven shrinkage across the component. This is usually due to uneven cooling across the material. Different cooling rates or rapid cooling leads to internal stresses.
- Flash
- If the clamp force is not sufficient, the mould/die are not precisely manufactured, the mould/die are worn or corroded or if the injection pressure is too high, there will be a leak of the polymer around the join leading to flashing.
Which of these issues can CAD solve?
CAD based analysis:
- Warp analysis: used to predict shrinkage as a result of stress on the mould
- Cooling analysis: checks for uniform cooling throughout the mould. Potentially reducing cooling time
22
Q
What are the important specs for injection moulding?
A
What are the important specs for injection moulding?
- Clamping force
- Keep as low as possible: reduce wear and tear without generating flash
- Injection pressure
- Mould internal pressure curve
- First speed of filling must be adequate
- Switch over to holding pressure
- No residual pressure when mould is opened
- Mould internal pressure curve
- Shot size: volume of the part plus runners and gates
- Closing force: needed to hold mould for packing and cooling
- Number of cavities x projected parting line part surface x mould cavity pressure
23
Q
Give a closing force example for injection moulding (see picture)
A
24
Q
What are the other techniques for injection moulding?
A
What are the other techniques for injection moulding?
Gas assisted injection moulding
- Shut off valve closes to prevent plastic material seeping back into injection head. Gas is injected into the core of the plastic, which is still molten. The gas progresses the molten plastic into the extremities of the cavity
Multi shot
Blow moulding
25
Give some advanced applications of polymers
Advanced applications of polymers:
Self-healing
Drug delivery
* Release from surface
* Diffuse from swollen network
* Release due to erosion
* Efficiency depends on chemical structure and porosity of particle
Organic solar cells
LEDs
* Holes injected into conductive layer, electrons injected in emissive layer, recombine at interface emitting light
26
What is hydrodynamic volume?
What is hydrodynamic volume?
It is an indication of the expansion factor alpha
High alpha means it is a good solvent
Solvent polymer interactions are higher than polymer polymer interactions
27
What properties depend on molecular weight?
What are the different measures for molecular weight?
What properties depend on molecular weight?
* Modulus
* Strength
* Viscosity
* Melting temperature
* Glass transition temperature
28
What is gel permeation chromotography
Gel permeation chromatography
* Type of size exclusion chromatography
* Measures molecular weight distribution and structure
* Separates based on the hydrodynamic volume of the polymer
* Higher MW, higher hydrodynamic volume
* Pores exclude large molecules, so they move faster through the column
Factors affecting GPC spectrum:
* Sample interaction with column
* Temperature
* Flow rate
* Gel permeation chromatography is a separation technique.
* The columns contained insoluble beads with a rigid pore structure.
* The pores can exclude very large molecules, allow partial permeation of medium sized polymers and allow total permeation of smaller molecules.
* The larger molecules therefore don’t have a long residence time in the column and flow through.
* This means the polymers are separated with the largest coming out first and smallest last.
* The full molecular weight distribution can be defined and compared with previous results to see if this is influencing the mechanical behaviour.
29
What is differential scanning calorimetry?
Differential scanning calorimetry
* Thermal energy of a sample is monitored as a function of temperature
* Measures thermal energy of phase transitions (crystallisation, melting point, Tg)
* Heat capacity increases above Tg
* Heat released on crystallisation and absorbed on melting
* The amount of energy needed to increase the temperature of a sample is measured.
* This detects phase transitions because of the quantity of energy needed to change temperature.
* The glass transition temperature can also be observed.
* Also, the percentage crystallinity can be defined.
30
What is thermogravimetric analysis?
Thermogravimetric analysis
* Measure thermal stability of a sample
* Mass of a sample is measured as a function of temperature
* Can identify material composition and presence of contaminants
* Characteristics different in inert or oxidising environment
* Derivative curve highlights different mass loss events
* Percentage weight loss can be used to calculate composition
* This thermal technique measures the rate of change in mass as a function of temperature.
* This can identify changes in the oxidative stability and the composition.
* This is a highly sensitive technique and any contamination would be immediately highlighted.
* This technique is often used to identify the percentage of filler in a polymer sample, which also effects the mechanical properties.
31
What is UV spectroscopy?
UV spectroscopy
* Can identify material composition and presence of contaminants
* Measures absorbance of UV by the sample
* Can be used to identify chromophores
* Absorbance proportional to concentration
32
What is fourier transform infrared spectroscopy
Fourier transform infrared spectroscopy
* Can identify material composition and presence of contaminants
* Measures vibration and stretching of chemical bonds
* Used to examine structure and presence of functional groups
* Samples can be solid, liquid or gas
33
What are the different techniques for classifying polymers?
* Gel permeation chromatography (GPC) – MW distribution
* Differential scanning calorimetry (DSC) – Thermal transitions
* Thermogravimetric analysis (TGA) – Thermal stability
* Ultraviolet-visible spectroscopy (UV/vis) – structure/composition
* Fourier transform Infrared spectroscopy (FTIR) – structure/composition
34
Define bio based polymers and drop in bio based polymers
Bio based polymers:
* Polymer produced from renewable natural resources e.g. PLA, PHA
Drop in bio-based polymers:
* Chemically identical to conventionally sourced polymers, but are (at least partially) produced from biomass e.g. PET, PE from ethanol feedstocks (sugar cane)
Polymers may be biodegradable: their properties deteriorate and may completely degrade under aerobic or anaerobic conditions
* Bio based may or may not be biodegradable.
* Tend to be starch based derived from potatoes or wood
* Or protein based for biomedical applications
Term bio polymers sometimes used to describe bio-compatible polymers suitable for biomedical applications
* E.g. silicone rubber, polyethylene, PMMA
Currently 2% of world production is bio-based polymers. However, it is increasing fast estimated 20% per year. Attention is focussing on a few polymers, particularly those showing potential for scale up and packaging.
35
What are the properties and applications of
Starch
PLA
PHA
What are the properties and applications of
Starch
* Blended with other polymers to make materials with range of properties
* Lower starch content associated with improved properties but decreased biodegradation
* Substitute for PE, PP and EPS
* Food and agricultural applications: bags, packaging
PLA
* Physical properties similar to PS
* Can be modified to resemble PE and PP
* Grease resistance comparable to PET
* Degrades by hydrolysis
* Food and medical applications: plastic plates and knives and forks
PHA
* Comparable to PP
* Can also substitute for PE and PVC
* Degrades in composting and anaerobic conditions
* Razors, toothbrushes, bags etc.
36
What is the production process of
* Starch
* PLA
* PHA
Production process of
* Starch:
* Wet milling of corn
* Extrude into TPS: add water and plasticiser
* Reactive blending: add PVA and PLC
* PLA
* Wet milling of corn into glucose
* Fermentation into lactic acid
* Polymerisation into PLA
* PHA
* Wet milling corn into glucose
* Fermentation and extraction into PHA
37
What are the issues with biopolymers?
Issues with biopolymers:
* Intensive agriculture
* Large scale monocultures
* Agrochemical use
* Irrigation
* Capacity, competition with food production
* Biopolymers cannot meet demand in near future
* Energy requirements
* Fossil fuels used for: synthetic fertilisers, pesticides, farm machines, lights, pumps, fans, heating, water
* Cost
* More expensive than conventional polymers
* Disposal
* Mechanical recycling
* Bio polymers contaminate conventional recycling
* Composting: home/industrial degrades into CO2 and water.
* Biopolymers not always suitable for home composting
* May not degrade in industrial composters or at all
* Feedstock or chemical recycling
* Energy recovery
* Landfill
* Bio polymers will generate methane if degradable in landfill
* Performance
38
What is an LCA, explain it for biopolymers
LCA
* Standardised framework for determining the environmental impact of product or process, to allow comparisons to be made
* But interpretation varies and users can select different options
* Should cover entire life cycle of product, but many studies don’t do this
Difficulties with biopolymers:
What should be included within agriculture:
* Soil carbon/nitrogen dynamics
* Nitrogen emissions from composting
* Manufacturing environment, maintenance of equipment
Location specific:
* Transport requirements
* Incineration efficiencies
* Farming practices
* Energy production is country specific
* Electricity has different impacts depending on how it is generated
Disposal often ignored
Studies look at limited impact factors
Impact categories include:
* Contribution to climate change
* Resource depletion
* Ozone depletion
* Energy and water use
* Acidification
* Eutrophication: increased nutrients in water systems resulting in excessive bland growth
* Toxicity
Can’t be combined: impacts are assessed separately
39
What are the future improvements for biopolymers?
Future improvements:
* Integrated system agriculture
* More use of renewable
* Alternative feedstocks
* Crop waste is used but energy requirements tend to be higher
* Consumer food waste: problems of contamination can be lower energy requirements
* Improved farming practices
* Reduction in agrochemicals
* Reduction in fuel costs
* Optimisation of polymer production processes
40
What is a laser? What are the different laser media?
What is a laser?
* Laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation
* Laser means: light amplification by stimulated emission of radiation
Stimulated photos have same:
Direction, polarisation, phase, wavelength
Laser resonator formed with mirrors either side of gain medium
41
What are the different laser mediums?
Different laser media:
* Gas: electrical discharge
* Solid state: optical excitation
* Semiconductor: electrical current
* Dye: optical excitation
Common properties:
* Directionality
* Brightness
* Monochromatic (narrow band of wavelengths)
* Spatial coherence (better focusability)
42
What are the different solid state laser geometries?
What does a fibre look like?
What are the different solid state laser geometries?
Rod
Slab
Thin disk
Cladding pumped fibres
What does a fibre look like?
43
What is the different between a fibre laser and a solid state laser?
44
What are the advantages of fibre lasers?
What are the advantages of fibre lasers?
* Excellent heat management
* High efficiency: low heat dissipation
* High surface area/volume: helps heat removal
* High mode quality
* Highly directional and coherent output
* Compact and robust
* No re-alignment
* Telecom leveraged
45
What are the different applications for fibre lasers?
What are the different applications for fibre lasers?
Material processing
* Welding
* Accurate and consistent processing: fast, flexible and high strength
* Low levels of thermal distortion
* Able to weld difficult applications
* 3d printing
* High levels of beam stability: stable and well controlled
* Process a variety of powders
* Ideal for AM: Inherent back reflection protection
* Cutting
* Highly productive: match leading cutting speeds
* High accuracy and repeatability: intelligent software and stability
* Large range of materials and thicknesses
* Energy efficient
* Ablation and cleaning
* No solvents/chemicals
* High quality, minimal heating, non contact
* Drilling
* Small feature size, high aspect ratios, various materials
* Micromachining
* Marking/engraving
* Permanent
* Non-contact: no wear
* Versatile application
* High speed, high precision
Sensing
* Vibration measurement
* Oil and gas exploration
* Remote gas sensing
* Terrestrial mapping
* Wind sensing
Healthcare
* Vision correction
* Kidney stone ablation
* Skin rejuvenation
* Soft tissue ablation
* Dentistry
Other
* Cinema projection
* Communications
* Directed energy weapons
Applications:
* Automotive: cutting, marking, welding
* Batteries: welding, drilling, engraving, marking
* Medical: welding, cutting
* Advanced manufacturing: micromachining
* Solar: cutting, marking, welding
* Aerospace: drilling, welding, cutting, marking
* Dental: engraving and marking
46
What are the important details for diamond turning?How is it used in IR lens production?
How are UV lens made?
Diamond turning
* Zero or slightly positive rake angle for soft materials
* Negative for IR materials
* Highest cutting speed that can be permitting whilst providing good dynamic stability
* Vacuum extraction of swarf to prevent scratching
* Flood oil or spray mist coolant on metals
* Hard brittle materials control the feed rate
* Depth of cut is less sensitive for hard materials
IR optics:
* Saw
* Rough grind
* Diamond turning
* Clean
* Coating
UV optics:
* Saw
* Lap
* Rough grind
* Fine grind
* Clean
* Ion beam figuring
* Cleaning
* Coating
47
Name the factors influencing workpiece accuracy and production capability
Factors influencing workpiece accuracy and production capability
Environment related
* Temp variation
* Vibrations
* Seismic
* Through pipes
* Air borne (noise)
* Electric noise
Workpiece related
* Stiffness variation
* Thermal distortion
* Clamping distortion
* Residual stresses
* Heat response
Process related
* Tool geometry
* Tool wear
* Tool mounting (dynamic stiffness)
* Process variations with tool wear
* Specific energy variations
* Cutting force variations
* Removal mode
* Coolant variations
Machine tool related
* Motional accuracy
* Deflection (stiffness)
* Thermal distortion
* Dynamic resonance’s
* Accuracy/ resolution of measuring systems
48
Describe the chip manufacturing process
Chip manufacturing process
* Silicon ingot sliced into blank wafers
* 20 to 30 processing steps later it is a
* Patterned wafer
* This is diced into individual dies
* This is tested and bonded to package
* This packaged die is then tested and shipped to customers
49
Describe microprocessors patterning process
Patterning process
* Prepare wafer
* Apply a photoresist
* Align a photomask (Cr and glass)
* Expose to UV light
* Develop and remove photoresist exposed to UV light
* Etch the exposed oxide
* Remove remaining photoresist
50
What are the three technologies that determine the performance of semiconductor lithography systems?
What are the three technologies that determine the performance of semiconductor lithography systems
1. Resolution capability of the projection lens: for forming extremely intricate electronic circuit patterns
* Consists of more than 20 lenses, some over 1m long
2. Alignment accuracy: ensuring that the next pattern is accurately aligned to the base pattern
* When electronic circuit patterns are repeatedly formed on a silicon wafer many times, they must be positioned with accuracy to the nanometre
3. Throughput: indicates the processing efficiency of a semiconductor lithography system
* Productivity during IC mass production is improved when high speed movements of the wafer stage and other processes increase throughput
51
Why is feature size important? What is the limitation to feature size?
Why is feature size important? What is the limitation to feature size?
* Progress in semiconductor manufacturing is all about reducing the size of the features that make up integrated circuit (IC) designs.
* Smaller features allow for faster and more advanced ICs that consume less power and can be produced at lower cost.
* Resolution limited by wavelength, currently extreme ultra violet is used
52
What are the other options for silicon chips?
What are the other options for silicon chips?
Quartz mask in contact with silicon
Mask pressed into molten layer of silico
53
How does roll to roll printing work?
How does roll to roll printing work?
* Raw materials
* Deposition
* Patterning
* Packaging
* Finished product
Examples include:
* OLED lighting
* Solar cells
* Flexible display
* Flexible battery
* Flexible RFID
54
What are the automation challenges of roll to roll printing?
What are the automation challenges of roll to roll printing?
* Register control: position match
* Tension control
* Synchronisation
* Positioning
* Cam calculation
* Winder
* Cross communication
* Motion control
* Virtual master
55
Which properties change with size?
Why do properties change?
How does size affect properties?
* Nanosized particles exhibit different properties than larger particles
Properties: describe how the material acts under certain conditions
Properties that often changes:
* Optical: colour, transparency
* Electrical: conductivity
* Physical: hardness, boiling point
* Chemical: reactivity, reaction rates
Why do properties change?
Four reasons:
* Gravitational forces become negligible and electromagnetic forces dominate
* Gravity is a function of mass
* Electromagnetic are not affected by mass
* Electromagnetic forces are 10^36 times stronger than gravity
* Quantum mechanics is used to describe motion and energy instead of classical mechanics
* Greater surface to volume ratios
* Greater amount of substance comes into contact with surrounding material
* Better catalysts
* Random molecular motion becomes more important
It is important to understand these factors when researching new materials and ways to manufacture goods from them
56
Describe nanoscribe
Nanoscribe:
* Laser beam sent through an inverted micro scope onto a piezoelectric 3D scanning stage
* Laser beam fired through lens to hardens material (light photoresist).
* Material hardens through polymerisation
* This process employs two photon photolytic techniques and high resolution positioning.
* The laser beam itself has a computer-controlled beam guidance system that translates a 3D CAD model directly into 3D structures of almost any complexity at any scale.
* Essentially it can fabricate microstructures as small as 500 nm, including those with complex geometries and support structures, at extremely high resolutions (100nm with reports of new materials reaching 45nm).
* The 3D printing technology that Nanoscribe developed has allowed sub-micron parts to be fabricated with geometries and internal structures that would be completely impossible to create using standard micro-scale manufacturing techniques.
57
Describe fountain pen lithography
Fountain pen nanolithography
* Deposit a nanoparticle dispersion of material
* FPN is a printing method, which, utilises a reservoir filled with nanoparticulate ink.
* These ink solutions can undergo nanochemical changes during the lithography process, resulting in the desired functional lines and structures.
* Line width control from 15 nm to over 1000 nm have been demonstrated.
* Line produced showed micrometer lengths, consistency of line dimensions, precise placement, and conductivity.
* Similar to the reservoir in fountain pens, the nanopipette reservoir enables numerous lines to be printed without refilling.
* This technology could be expanded to the production of conductors and actuators, correction of flat panel displays, and mask repair applications.
58
Describe ion beam machining
Ion beam machining
* Ion source fired through imaging gas
* This is then focused through apertures and scanning deflectors
* Before being fired through the final lens at the workpiece
* Size of feature determined by size of ion:
* Gallium (largest)
* Neon
* Helium (smallest, 0.5nm)
59
How is core of composites manufactured?
Manufacture of core such as honeycomb
Tends to be batch production
* Labour intensive
* Aluminium: print wheel adds adhesive to aluminium foil
* Strips are cut and stuck together
* Heated under pressure
* Cut and expanded
* Nomex: print wheel similar
* Cut and stuck together
* Heated under pressure
* Expanded and heat set
* Dip in phenolic resin and cured at 150 degrees
60
How is carbon fibre manufactured?
How is carbon fibre manufactured?
* Bulk chemical: AN
* Batch is then polymerised: PAN
* Dope (high energy required in solvent recovery process)
* Fibres are then spun
* Fibres are washed and stretched: PAN precursor fibre
* Oxidise and carbonise: slow process
* Surface treatment and sizing
61
What is prepreg? What are the advantages and disadvantages?
What is prepreg? What are the advantages and disadvantages?
Prepreg: resign pre-impregnated reinforcement, typically thermoset epoxy UD tape for cure in autoclave, automatically laid up for aerospace applications
Advantages
Resin levels accurately set by supplier
Uni directional (UD) fibre is aligned to structural loads
Allows for complex lay ups in automated processes
Cana use high viscosity matrices for high toughness and damage tolerance
Disadvantages
Higher material cost from multi-step process and cold supply chain
Needs expensive tooling capable of withstanding high temps and pressures
Debulking need on thicker laminates
62
How is prepreg manufactured?
How is prepreg manufactured?
Solvent impregnation process:
* Carbon fibres sheets rolled out.
* Accumulator at either ends to tension the fibre and to allow the process to run continuously between rolls.
* Sheets go through solvent to add resin
* Sheets travel up column and undergo solvent management
* Inspection Light - to test if light can go through (pass or fail test)
* Compaction rollers
* Total weight inspection
* Protective poly at the end to separate fibres.
Prepreg impregnation process:
* Resin is pressed onto paper using a film weight check
* In separate process carbon fibres are rolled out
* As this happens paper covered in resin is pressed each side of the fibres
* It is heated in a heat table
* It is then cooled and paper is removed leaving the resin on the fibres
* Light table used to measure consistency of fibres
* Then protective poly is rolled on
High volume, low cost process
Residual solvent is a problem
Negative environmental impact
63
What are the different manufacturing methods with prepreg?
Manufacturing with prepreg
* Hand Lay Up - High waste, low investment, high labour
* Automated Tape Lay Up - Medium waste, moderate investment, lower labour
* Automated Fibre Placement - low waste, high investment, little labour
64
What are the alternative methods for manufacturing composites?
What are the alternative methods for manufacturing composites?
* Compression moulding: fibres are chopped and compressed with compacting rollers and resin
* Infusion: fibres are laid in part and resin is injected under a vacuum throughout the part
* Thermoplastic prepreg
65
What are the new trends in fibre growth?
What are the new trends in fibre growth?
Wider:
* Bigger, stiffer roller sets, more powerful motors
* Demand for single product to avoid cost of changes
* No defects in production or delays = QUALITY
Faster:
* Same time in process therefore longer equipment
* New chemistry: faster reactions therefore shorter process time
Heavier
* Thicker filaments currently have poorer properties as they are less uniform
* More filaments per tow: properties affected by oxygen diffusion into bundle
66
What are the important parameters for successful bonding?
Why is viscosity important?
What is thixotropy? Why is it important for adhesives?
What are the important parameters for successful bonding?
* Design of the joint
* Adhesive selection
* Surface preparation
* Substrate and conditions in service
Why is viscosity important?
* Dictates the application methods required for material use.
* High viscosity can be difficult to remove
* Low viscosity can flow to much and run off surfaces
Thixotropy: indication of a material’s decrease in viscosity over time while under stress.
Indicate an adhesives ability to fill gaps between substrates
Predict a product’s resistance to sagging vertical surfaces
67
Why is lap shear strength important?
Why is peel strength important?
How are tensile properties are measured?
What is gel time?
Why is lap shear strength important?
* Gives a measure of ultimate load and a way of comparing adhesive strength
* Cohesive failure: adhesive remains on both substrates, indicating a strong bond
* Adhesive failure: adhesive remains on one substrate, indicating selection of the wrong adhesive for substrates
Why is peel strength important?
* Peel strength is a measure of a material’s ability to withstand vibration and stretching without deforming or breaking.
* Important indication of an adhesive’s toughnessand ability to produce joints that can withstand difficult service conditions
Tensile properties are measured by:
* Elongation: amount of stretch required to break a specimen
* Ultimate tensile strength
Gel time, work life and pot life are terms used interchangeably to indicate:
* The amount of time at room temperature from initial mixing until the mixture can no longer be stirred.
* Gel time can be increased or decreased by cooling or heating the resin or hardener
68
What factors are considered when selecting an adhesive?
What factors are considered when selecting an adhesive?
Substrates to bond
Cure speed, pot life, gap filling, colour
Chemical resistance, temperature resistance
Specific approvals
69
What are the different joint loading conditions?
What are the different joint loading conditions?
* Tension
* Compression
* Shear
* Cleavage
* Peel
70
What is AM?
What is AM?
* AM is the layer by layer deposition of material to make a part
* Additive manufacturing is a process where:
* Digital 3D design data is used to build up a component in layers by depositing material.
* 3D printing is increasingly used as a synonym for AM.
* However, AM is more accurate in that it describes a professional production technique which is clearly distinguishing from conventional methods of material removal.
71
What are the different AM methods?
What are the different AM methods?
* **VAT photo polymerisation (StereoLithogrAphy):** material is cured by light activated polymerisation
* Continuous liquid interphase production: continuous elevation, liquid resign, o2 permeable window
* Advantages: good resolution, surface finish and rapid
* Disadvantages: limited materials, messy, support removal
* **Material jetting:** droplets of build material are jetted to form an object
* UV lamp and inkjet heads and levelling roller
* **Binder jetting:** liquid bonding agent is jetted to join powder materials
* **Material extrusion (Fused Filament Fabrication):** material is selectively dispensed through a nozzle and solidifies
* Advantages: widest range of materials, widest range of processing conditions, multi material, dedicated support material
* Disadvantages: surface finish, toolpath planning, slow rate
* **Sheet lamination (LOM):** sheets are bonded to form an object
* **Powder bed fusion (Selective Laser Sintering/SLM):** energy (typically a laser or electron beam) is used to selectively fuse regions of a powder bed
* Mount platform, heat bed, perform cycle, cool, remove platform, post process (CNC, surface finish, anneal etc)
* Advantages: can print metals, rapid, good surface finish, wide variety of materials
* Disadvantages: powder handling, high energy, post processing
* **Directed energy deposition (LENS):** focused thermal energy is used to fuse materials by melting as deposition occurs
* Powder fired into a laser beam
72
Why is AM increasingly widespread now?
Why is AM increasingly widespread now?
* Rapid prototyping
* Reducing assembly
* Complex geometries
* Multi material
* Enhanced performance
* Low volume manufacturing
* Supply chain efficiency (low inventory)
* Reduced material consumption
73
Explain vat photo polymerisation
VAT photo polymerisation (StereoLithogrAphy):material is cured by light activated polymerisation
* Continuous liquid interphase production: continuous elevation, liquid resign, o2 permeable window
* Advantages: good resolution, surface finish and rapid
* Disadvantages: limited materials, messy, support removal
74
Explain material extrusion and its ads and disads
**Material extrusion (Fused Filament Fabrication):** material is selectively dispensed through a nozzle and solidifies
* Advantages: widest range of materials, widest range of processing conditions, multi material, dedicated support material
* Disadvantages: surface finish, toolpath planning, slow rate
75
Explain powder bed fusion and advantages
**Powder bed fusion (Selective Laser Sintering/SLM):** energy (typically a laser or electron beam) is used to selectively fuse regions of a powder bed
* Mount platform, heat bed, perform cycle, cool, remove platform, post process (CNC, surface finish, anneal etc)
* Advantages: can print metals, rapid, good surface finish, wide variety of materials
* Disadvantages: powder handling, high energy, post processing
76
Explain material jetting, sheet lamination, directed energy deposition
* Material jetting: droplets of build material are jetted to form an object
* UV lamp and inkjet heads and levelling roller
* Sheet lamination (LOM): sheets are bonded to form an object
* Directed energy deposition (LENS): focused thermal energy is used to fuse materials by melting as deposition occurs
* Powder fired into a laser beam
77
What are the drawbacks of AM?
What are the drawbacks of AM?
* Machine cost (barrier to entry, limited volume)
* Material cost
* Throughput
* Quality
* Process control
* Increased validation and demonstration, supported by standards for certification and process operation
78
What are the different types of engineered ceramics?
What are their properties?
What are the different types of engineered ceramics?
* Oxides:
* Aluminas
* Quartz/silicates
* Yttria
* Zirconias
* Non oxides
* Carbides
* Nitrides
Material properties
* Harder and stiffer than steels
* More heat and corrosion resistant than metals or polymers
* Lower density than most metals and allows
* Raw materials are plentiful
* Display wide range of properties to facilitate use in different product areas
79
How are ceramics made?
How are ceramics made?
Material prep: chemical, physical, morphological
* Weigh materials, milling, add binder, spray dry, characterise powder
Forming: process options, dimensional and density control
* Dry powder: isostatic press, roll compaction, hot press
* Casting: tape cast, slip cast, pressure cast
* Plastic forming: extrusion, injection mould
* Chemical vapor deposition
Firing: kiln options, temp & time, refractory, atmosphere
* Continuous, batch, atmosphere, vacuum, HIP, hot press
Finishing: shape & tolerance, finish, features, assembly
* Shaping: CNC grinding, laser machining, cutting
* Surface treatment: metallizing, plating and glazing, coating
* Assembly: brazing, solder, adhesive
* Specialised: cleanroom assembly, inspection and test, materials R&D
80
Why use ceramics?
Why use ceramics?
Mechanical
* Hardness
* Rigidity
* Toughness
* Wear
Chemical
* Corrosion
* Biocompatible
* Ultra-pure
* Inert (or active)
Thermal
* Shock & stability
* Conductivity
* Expansion
* Creep
Electrical
* Resistivity
* Conductivity
* ESD – safe
* Dielectric strength
81
What are the different applications for ceramics?
Applications of alumina:
* Beverage valves: hardness, rigidity, strength, corrosion resistant and inert
* Improved lifetime
* Improved portion control
* Improved product quality
* Precision metering pumps: hard, rigid, strength, wear, corrosion resistant, biocompatible, inert
* Accurate dosing and long life
* Ceramic provides dimensional stability
Applications of zirconia
* Diesel engine injector link: hardness, strength, wear, corrosion resistant, thermal stability
* Improved lifetime, reduced warranty claims, improved fuel economy
Applications of carbides
* Body armour: hardness, strength, weight
* Lives saves, weight reduction, improved ballistic protection
* Satellite mirrors: rigidity, strength, weight, thermal conductivity and expansion
* Strong, stiff and lightweight
* Temperature capability, ultra-fine finish
Applications of nitrides
* Hybrid bearings: hardness, strength, wear, corrosion resistant, inert
* Higher speeds and throughput
* Improved runout and part accuracy
* Cooler operation, less downtime
MET 2B
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