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Direct Writing Technology Advances and Developments
K K B Hon*, L Li** and A Malshe***University of Liverpool*University of Manchester**University of Arkansas***
STC ‘E’ 2008 Keynote Paper
What is Direct Writing?
• Direct Write covers a range of technologies, possibly in reconfigurable short production runs, of two or three dimensional functional structures using processes that are compatible with being carried out directly onto potentially large complex shapes.
PA, 2004
• Any techniques or process capable of depositing, dispensing or processing different types of materials over various surfaces following a preset pattern or layout.
A Pique & D B Chrisey, 2002
What is Direct Writing?
• The intent is to address combinations of:• Functional structures
• Vast range of substrates (materials/shapes)
• High precision in form or function
• Multi length scale
• Reconfigurable
• Direct fabrication
• Robust final product
What is Direct Writing?
• Digital deposition of functional materials onto a substrate surface.
Layout of Paper - 1
1.0 Introduction
Background and overview
2.0 Direct Writing Technologies
Classifications of DW technologies based on materials transfer processes and length-scale
Relationship with conventional RP technology (FDM, LENS, 3DP)
Layout of Paper - 2
3.0 Laser-based processesTechnology description, process principles, key characteristics, process performance.
4.0 Inkjet-based processes
5.0 Syringe-based Processes
Layout of Paper - 3
6.0 Emerging Processes6.1 Focussed ion and electron beam6.2 Nano-printing6.3 Scanning probe approaches6.4 Other methods (thermal spray, electrostatic,
electrophoretic, etc)
7.0 Industrial Applications of DW7.1 Materials and substrates: organic, inorganic
and biological7.2 Electronic and devices
Layout of Paper - 4
8.0 Conclusions
9.0 Acknowledgements
10.0 References
Types of DW Technologies
DW Addition
Direct Control Interim Tools
Nozzle Technique
Laser Techniques
Focus Spraying
Screen Printing
Soft Litho
Ink Jet Displacement Pumps
Droplet control
Optimisation for:
- low shear
- pastes/slurries
- sintering/curing
- etc
DMD LCVD LENS
Maskless Mesoscale Material Deposition- M3D
Flexible Maskless approach
direct from CAD
Mesoscale Feature Sizes
<10 to >>100+ µm
Low-Temperature Substrates
High Aspect Ratios
Conformal
Non-Contact (Stand-Off)
Wide Range of Materials
Reduced chemical usageOptomec
M3D Electronics Samples
Wide Range of Materials1-1000 cP source materialCommercial and Custom
ConductorsMetals: Cu, Ag, Pt, Au, Pt/Rh, PdConductive Polymers
Insulators Adhesives Wide Variety of Substrates
Rigid and FlexKapton, FR4, Si, Plastics, Metals
Smart Card Inductor on Flex
GPS AntennaRedistribution
500 µm TrenchResistor Pads
Characteristics of Syringe-based DW
• Conformal and non-contact.
• 25 µm feature size.• Wide materials range from
5 to 106 cP.• Laser surface mapping..• In-situ laser sintering.
• Mesoscale geometries.
• Complex patterns from CAD.
• 25 µm feature size.
Capabilities of Syringe-based DW system
K H Church
Line Dynamics and Stability
Use of Rayleigh-Taylor Criterion for Instability analysis.
K H Church
Production of Passive RLC Components
15nH two-turn inductorKapton substrate, 0.005”0.150” diameter
Resistor array on microscope slide
1pF Microstrip Interdigitated capacitor, 0.005” Kapton Film Substrate
25pF Multi-leaded RF bypass capacitor
LC network designed for shunt LC resonance at 1.1GHz K H Church
Droplet Formation
Drops form at high acoustic frequencies
10 kHz formation rate gives fluid shear rates in the region of 104 s-1
Each drop is identical and travels at velocities 2 – 4 ms-1
B Derby
Detail of Tracks Produced by Inkjet DW
Droplet control and optimisation is essential.
Track width depends on surface wetting characteristics but typical size and separation of around 100 μm is possible.
B Derby
Applicability of DW Technology
Direct Write products
Bulk structures
Sacrificial parts for tooling
Products
Mould tools
Functional materials
Passive structures
Active devices
Optical waveguide
Electronic circuitry
Switch, batterySwitch,
OLEDinterconnect, antenna, filter
resistor, capacitor, filter, etc
Active
λ filter, delay, attenuator,etc
structures
Coatings
Passive
Drug, diagnostics,
assays, sensors
Labels, filters, thermal
conductors etc
Magnetics
Solar cells
Prototypes
M Humphries & J Townsend
Direct Writing Applications in Defence
Graded materials eg
thermal barrier coatings
High strain actuators
Advanced piezoelectric transducers
Porous cathode
Porous anode
Catalyst layerFuel cells
D Burgess
Process Comparisons
J W Sears
Frequency Selective Surface Produced by DW
-25
-20
-15
-10
-5
0
8 9 10 11 12 13
Frequency (GHz)
Att
enu
atio
n (
db
)
Flat Panel
Curved Panel
Performance of the FSS
• Broader peak• Lower attenuation
Summary of Progress
Structure of paper.Database with over 200 references.IS&T Conference on Digital Fabrication first launched in 2005.Multi-scale nature of DW technology.Application domains and case studies.Scientific principles of DW processes.Background materials of DW systems.Issues on common RP processes and DW processes overlap.
Contributions from CIRP Members
Please send your comments and contributions to:
CIRP E K/N 2008
Could direct writing make some of these components ?
• Layer deposition techniques
• Molecular beam epitaxy
• Vapour phase epitaxy etc.
• Sculpture techniques
• Chemical, mechanical, etching
Transistor
MEMS
Controllable RAM
Environmental transducers
Conclusions:
• Nanotechnology will be crucial for MoD in many areas
• But MoD does not buy technology
• MoD will not be aware of the manufacturing technique
• Materials Domain keen to see direct writing used
• Funding possibilities
• Developments of Defence - specific technology
• Demonstration of sub-systems using direct writing techniques
• Aim is demonstration not technology development
DIRECT SCOPING STUDY – PART 1
• Definitions
• Technologies and Processes
• Benefits
• Limitations
• UK Activities
• Application Areas and Sectors
• Timescales and Supply Chain
• Barriers
Direct write has significant potential
• Direct Write has the potential for major direct and indirect impact on:
– markets of importance to the UK
– exploiting valuable capabilities in the UK
• The onus is on end users, through consultation and collaboration, to identify where Direct Write may best be applied
Contributions Received
Prof. T Pfeifer
Prof. G Chryssolouris
One another.
DIRECT WRITE SCOPING STUDY – PART 1…
What is Direct Writing?
•The term Direct Write is used is used here to describe a range of technologies, possibly in reconfigurable short production runs, of two or three dimensional functional structures using processes that are compatible with being carried out directly onto potentially large complex shapes
DIRECT WRITE SCOPING STUDY – PART 1…What are the Direct Write Technologies and Processes?
DW
Add material
Modify material
Broad, unrestrained addition
Localised addition
Interim process tool (mould,
mask)
Functional Active / Passive structure
Localised processing
PC/CAD control
Interim process tool (mould,
mask)
PC/CAD control
DW
Add material
Modify material
Broad, unrestrained addition
Localised addition
Interim process tool (mould,
mask)
Functional Active / Passive structure
Localised processing
PC/CAD control
Interim process tool (mould,
mask)
PC/CAD control
DIRECT WRITE SCOPING STUDY – PART 1…
Technology hierarchies and maturity
Processes
Components
Subsystems
Materials
Design rulesCAD Measurement
ScanningDispensing Handling Etc.
Nozzles PumpsFluidics Control systems Software
Materials Formulation Scaled up materials processing Dispensate Structures
Processes
Components
Subsystems
Materials
Design rulesCAD Measurement
ScanningDispensing Handling Etc.
Nozzles PumpsFluidics Control systems Software
Materials Formulation Scaled up materials processing Dispensate Structures
DIRECT SCOPING STUDY – PART 2
• Definitions
• Technologies and Processes
• Benefits
• Limitations
• UK Activities
• Application Areas and Sectors
• Timescales and Supply Chain
• Barriers
DIRECT WRITE SCOPING STUDY – PART 2…Direct Writing enables a diverse range of benefits
• Rapid and cost effective prototyping– using diverse functional materials
• Mass customisation– high volume one-offs
• Creation of new products– novel features
• Advanced manufacturing– disrupting the Supply Chain
DIRECT WRITE SCOPING STUDY – PART 2…
Recognise that there are limitations
• Cost associated with flexibility
• Constraints on material selection
• Resolution achievable
• Yield impact late in manufacturing process
Applications must be selected where the benefits underpin marketdriven needs
DIRECT WRITE SCOPING STUDY – PART 2…
UK capability and benchmarks
Keyword in Grant
“Inkjet”
EPSRC NSF
“Direct writ*” α
“Soft lithography”
20 (£4,115434)
17 (£2,172,937)
3 (£10,591,879)
26
37
17
“functional coat*” 15 (£2,543,708) 3
“Nano pattern*” 11 (£11,478,310) 8
“Screen print*” 20 (£3,605,555) 10
0%
5%
10%
15%
20%
25%
30%
35%
40%
45%
50%
55%
60%
65%
USA Europe A s ia UK
% p
ub
licat
ion
s
Publications 2000-2003 inclu. laser with (direct
writ*)
0%
5%
10%
15%
20%
25%
30%
35%
40%
45%
50%
55%
USA Europe China Singapore UK Other Asia
% p
ub
lica
tio
ns
Publications 2000-2003 inclu. in soft lithography
* indicates a truncated term
α this group may include vacuum processes not relevant to this study
0 %
5 %
10 %
15 %
20 %
25 %
30 %
35 %
USA UK
Japa
n
The N
ethe
rland
s
Franc
eO
ther
% p
ub
licat
ion
s
Publications 2000-2003 inclu. inkjet with polymer
electronics or (direct writ*)
DIRECT WRITE SCOPING STUDY – PART 2…UK is active in researching materials through to process
University of Arizona (bio microjets)
Materials - ‘inks’Understands
underlying physics; Develops new
chemistries
Process –‘Printhead’
Develops and optimises delivery
elements
Production –handling
Develops systems and bulk handling
techniques for production
UMIST (printing systems)
University of Cambridge (plastic electronics, displays)
UK research
ROW research
Fraunhofer ResearchNaval Research Labs (printable batteries)
Anglia Polytechnic University (relief maps)
University of Illinois –(thermopen ceramics
micro fluidics)
University of California, (plastic electronics,
displays, metal droplet)
University of Virginia (inkjet, self assembled monolayers)
Imperial College, London (polymer semiconductors)
National Renewable Energy Lab (direct metallization for solar
cells)
École Supérieure, Limoges (3D
piezoceramics)
MIT (ceramics, nanosensor structures)
Linköping University (plastic electronics, inkjet)
Queen Mary , University of London (atomisation
printing)
Chemnitz University of Technology (polymer
printing)
University of Nottingham (Cold Gas Dynamic
Spraying)
Carbon Based Electronics consortium activities in
polymers include Bangor, Cambridge, Imperial,
Kings College & University College,London
State University, New York (thermal spray)
US funding through DARPA’sMICE, made widely reported
process developments but interviewees report development
has slowed since programme completion
University of Liverpool (polymers, Cold Gas Dynamic Spraying)
DIRECT WRITE SCOPING STUDY – PART 2…UK is active across supply chain’s for inkjet technology
Philips
EPSON
Motorola
Du Pont
Dow
Flint Inks
Spectra
Litrex
RolltronicsSuperior micropowders
Seiko Epson
ROW commercia
l
Xaar
Patterning Technologies Ltd
RTC circuits
Gwent Electronic Materials L:td
Plastic Logic
Avecia
Xerox
Optomec Design
QMP –Qinetiq Metal Printing
Microfab Inc.
Lucent
STMicroelectroincs
Microfab Technologies Inc
Materials - ‘inks’Understands
underlying physics; Develops new
chemistries
Process –‘Printhead
Develops and optimises delivery
elements
Production –handling
Develops systems and bulk handling
techniques for production
New Polymer Electronics programme EU Framework - PolyApply, (extension of PolyScene) announced 2003. Designed to link with EU companies outside traditional electronics or plastics and to
exploit advanced in polymer materials
Sciperio
Conductive Inkjet Technology Ltd (Xennia Technology Ltd, Carclo plc)
Imaging Technology International
OhmcraftHitachi
UK commercia
l
Inca
DIRECT WRITE SCOPING STUDY – PART 2…
Sector overview ICT BiotechnologyAdvanced
manufacturingAdvanced materials
Energy & Environment
Example end use
Large area, distributed sensors e.g. RFID tags, integrated sensors e.g. vehicle monitoring Displays – consumer goods, automotive
Bioscaffolds , in vivo repair- bone, tooth or other tissue
Biochips – custom test arrays
Diverse markets –e.g. packaging & other industrial processes -Pharmaceutical process improvement
Diverse markets –biotechnology,electronics etc. Nanotechnology sector may be better enabled
Instrumentation, fuel cells, solar cells, batteries etc.
Threats and issues
Benefits already identified
Rapid prototyping
Mass customisation Conformal shapes
Large areas
Lightweight
Rapid prototyping
Mass customisation
Conformal shapes
Distributed large areas
Other more mature processes have have considerably more investment driven momentum
Immature supply chain, systems etc with limited qualification
Rapid prototyping
Mass customisation
Cost reduction by supply chain rationalisation
Process sensitive to materials & target accuracy
Process ‘sensitive’ to materials properties, e.g. cells
Smaller scale enabled e.g. monolayers
Potential energy saving impact energy savings
The technologies are considered applicable to many sectors
DIRECT WRITE SCOPING STUDY – PART 2…
been predicted across a range of sectors from Automotive to Pharmaceuticals/Healthcare
• Automotive– lightweight conformal currently
– sensors and instrumentation
– custom designs
– rapid prototyping of functional structures
• Pharma/Healthcare– processes for accurately dispensing actives
– diagnostic tools for drug discovery and genomics
– cell handling for diagnostics, bioscaffold repair, prosthetics
DIRECT WRITE SCOPING STUDY – PART 2…Applications will emerge in different timescales
• Rapid prototyping– PCB’s
– Biochips
• Mass customisation– custom chemistry
– parallel chemistry
– ceramic goods
– electronic tags
• Novel products– electronic
functionality on personal equipment
– automotive structures
– displays
– sensor arrays
– batteries
• Advanced manufacturing
– PCB
– repair of high value goods
And some are being developed now…
DIRECT WRITE SCOPING STUDY – PART 2…Direct and indirect benefits may impact some segments of the supply chain preferentially
DIRECT WRITE SCOPING STUDY – PART 2…Although considerable benefit to UK is expected, a number of barriers need to be overcome
• Low awareness and infrastructure– potential benefits, ability to test, development
support, design rules
• Potentially incomplete Supply Chain
• Legacy and investment in other technologies
• Perception of high investment cost
DIRECT WRITE SCOPING STUDY – PART 2…Numerous benefits arise from Direct Write capability
•The challenge for adopters is to identify where the benefits underpin market driven needs to enhance business performance
Agenda
DIRECT WRITE SCOPING STUDY – WORKSHOP…
Objectives
• Within each sector group, identify:• Relevance of Direct Write and its application
• Key benefits and how they will be delivered
• What needs to be in place for exploitation
• How specific barriers will be overcome
DIRECT WRITE SCOPING STUDY – WORKSHOP…
Process
• Split into sector teams
• Appoint scribe and presenter
• Address the specific questions
• Summarise discussions
• Feedback to the group
• Logistics– timings
– groups
– locations
Layout of Paper - 2
3.0 Laser-based DW processes3.1 Evolution of measures3.2 Measures for manufacturing systems
Classification of measuresBasic measures