This work is part of the COPE collaborative project co-funded by the UK Technology Strategy Board (TSB) and EPSRC.

Conformal Inkjet Direct Write on Aerospace Components

Industrial Doctorate Centre and BAE Systems

Mau Yuen Chan

Prof. Alan Champneys

Dr. Jagjit Sidhu

Dr. Paul Warr

This work is part of the COPE collaborative project co-funded by the UK Technology Strategy Board (TSB) and EPSRC.

• What is direct write (DW)?

• Differences in method to traditional lithography

• Benefits of DW?

• What advantages it brings

• The challenges faced during the study

• The DW system

This Presentation

This work is part of the COPE collaborative project co-funded by the UK Technology Strategy Board (TSB) and EPSRC.

A freeform patterning and deposition technique

• Completes patterning and deposition simultaneously

• Encompasses different deposition techniques

• Droplet

• Laser

• Flow

• Tip

• No single ‘perfect’ technique

• Innovative applications

Direct Write

This work is part of the COPE collaborative project co-funded by the UK Technology Strategy Board (TSB) and EPSRC.

Comparison to Convention

Lithography

• Requires the use of masks

• Large material wastage

• Changes to designs costly

• Etch step limits substrate material type

• Substrates must be relatively planar

• High capital cost

Direct Write

• Freeform patterning

•Low material wastage

• Mass customisation

• Variety of substrate materials possible

• Substrates can be non-planar

• Lower capital costs

This work is part of the COPE collaborative project co-funded by the UK Technology Strategy Board (TSB) and EPSRC.

• Benefits:

• Higher material efficiency

• Mass customisation

• Increased design freedom

• Integrated functionality

• COPE Project

• Replacing electronic wiring

with DW solution

Benefits for

This work is part of the COPE collaborative project co-funded by the UK Technology Strategy Board (TSB) and EPSRC.

• Aerospace Helmet used by pilots

• Recognised as the most advanced helmet in the world

• Undergoes further development to keep competitiveness • Even during the project study

The Helmet Shell

• Features: • Complex concave Shape • Carbon fibre substrate • Head tracking system; composed of LEDs and flexible connectors for wiring

This work is part of the COPE collaborative project co-funded by the UK Technology Strategy Board (TSB) and EPSRC.

The DW Process

Design

Execution

Evaluation

This work is part of the COPE collaborative project co-funded by the UK Technology Strategy Board (TSB) and EPSRC.

Challenges

Challenge Solution Enabled by

Complex shaped structures Conformal printing 5-axis motion controller

Low thermal tolerance of substrate Localised post-processing iCure

Lower than bulk electrical conductivity Electrodeposition of conductive metal Electroplating head

Linking DW and existing hardware Connector Connector tab

This work is part of the COPE collaborative project co-funded by the UK Technology Strategy Board (TSB) and EPSRC.

Multi-discipline

Printing

system Inks and

substrates

Post-

processing

DW printed component

Electroplating

Mechatronics

Thermal Science &

Physical Chemistry

Physical Chemistry

Electrochemistry

Business

Multi-layers

Electrical Engineering Mechanical Engineering Computer Science Control Systems

This work is part of the COPE collaborative project co-funded by the UK Technology Strategy Board (TSB) and EPSRC.

• The ‘creative brain’

• MasterCam is a CAD/CAM design software

• Originally a software program for milling applications

• Used to manipulate CAD models and design DW tracks

• Output: Movement scripts for the

motion controller

MasterCam®

This work is part of the COPE collaborative project co-funded by the UK Technology Strategy Board (TSB) and EPSRC.

• The ‘arm’

• A motion control robot with five degrees of freedom giving it a large work envelop

• All tools mounted onto working face • Required mechanical integration

• Precision controlled (0.001mm accuracy)

5-axis Motion Controller

150µm

100µm

50µm

This work is part of the COPE collaborative project co-funded by the UK Technology Strategy Board (TSB) and EPSRC.

• The ‘pen’

• Single nozzle jetting device (MicroFab)

• Inks used • Polymer dielectric ink • Silver conductive nanoparticle ink

• Can jet many materials

• May require post-processing to functionalise

Inkjet Printer

This work is part of the COPE collaborative project co-funded by the UK Technology Strategy Board (TSB) and EPSRC.

• UV energy delivery system • Required for curing polymer dielectric ink

• Controllable and localised output

• Curing regime affects silver behaviour

Bluewave® System

This work is part of the COPE collaborative project co-funded by the UK Technology Strategy Board (TSB) and EPSRC.

• Thermal spot delivery system for sintering • Delivers focussed broad-band optical

energy

+ Controlled thermal exposure + Superior electrical properties than oven sintering - Difficulty on thermally conductive substrates - Inks needed to be modified to match process

iCure™ System

This work is part of the COPE collaborative project co-funded by the UK Technology Strategy Board (TSB) and EPSRC.

• 4-point bend test used to investigate possible thermal damage caused by iCure process

• Sintering requires at least 2.0W of energy • Speeds kept constant

• Failure modes: • Compression – Resin failure • Tension – Fibre pull out

• Significant loss in mechanical stability

at more intense exposures

Thermal Damage

This work is part of the COPE collaborative project co-funded by the UK Technology Strategy Board (TSB) and EPSRC.

• Chosen as a method of improving electrical conductivity of DW tracks • Improvement to DW track conductivities (reaching ~50-70% bulk Cu)

• Uses brush plating method to deposit copper

• Several designs iterated:

• Improvement to electrolyte flow • Higher current density • Lower surface damage to copper deposit • Be able to navigate around complex 3D structures • Automatic feed/extract system for fluid

• Further improvements:

• Use of local cathode ‘ring’ for local connection

Electroplating

This work is part of the COPE collaborative project co-funded by the UK Technology Strategy Board (TSB) and EPSRC.

• Communications with the manufacturer • Requirements capturing • Resolving needs and expectations • Suitable for existing processes

• Several designs created for manufacturer’s approval

• Final design: Connector tab (c)

• Soldered into place • Flexible

Connector Tabs

This work is part of the COPE collaborative project co-funded by the UK Technology Strategy Board (TSB) and EPSRC.

• Aim: To replace chunky wiring in helmet shell with an integrated DW solution

• DW elements successfully fabricated onto a section of the helmet shell • Hardware and DW elements were connected • DW elements passed preliminary round of aerospace durability tests

The DW Helmet

This work is part of the COPE collaborative project co-funded by the UK Technology Strategy Board (TSB) and EPSRC.

DW electronics demonstrated on an aerospace component

• Developed a process that can fabricate DW electronics onto complex 3D structures

• Future work:

• Innovative full DW solutions to electronic applications • Repair work on damaged DW components • Scaling of process for full manufacturing environments

Conclusions

This work is part of the COPE collaborative project co-funded by the UK Technology Strategy Board (TSB) and EPSRC.

Questions?

The End