Editorial

Bruce Routledge has done a fantastic innovative job in creating the ICT Journal and editing it for the past 10 years. Perhaps it would be impolite to mention his age but unfortunately the time has come for him to shut down his laptop and pass on the responsibility of the Journal to others.

We really want the Journal to continue and flourish. Regular readers will know that Bruce was always asking for papers and articles to include in the Journal. We want to expand the scope of the Journal to make it a source of news, updates and information about our individual members, our corporate members and the PCB industry, as well as being the Technical Journal of our Institute.

We can't create something from nothing so it really is “As Good As We Get”.  At the moment I have volunteered to act as publisher. That means collating material that is submitted and preparing it into a format that will be distributed to members on a regular basis.

We currently have 400+ individual members at all levels of experience and expertise, mainly UK based with a significant number of overseas members. We have 18 corporate members who represent the complete breadth of PCB manufacturers, equipment providers and chemical suppliers. If you have something that you believe may be of interest to our members then please let me know. If you have company news then shout about it here. If you have an innovative process or equipment development then our members will want to know about it. If you have a research or development project then report the results and involve our members here.

Don't forget that there are no charges for items published. There are no adverts and no hidden fees! We can accept virtually any form of input such as presentation files with notes, photos, text, word documents and publisher files. Please see some guidelines at the end of the journal - Link to guidelines

I look forward to the next phase of our Journal with keen anticipation.

Richard Wood-Roe

This email address is being protected from spambots. You need JavaScript enabled to view it.

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ICT Council Members

 Andy Cobley (Chairman), Steve Payne (Deputy Chairman), Chris Wall (Treasurer), William Wilkie (Membership Secretary & Events), Bruce Routledge (the Journal) Richard Wood-Roe (Web Site),Martin Goosey, Lynn Houghton, Maurice Hubert, Lawson Lightfoot, Peter Starkey, Francesca Stern, Bob Willis and Matthew Beadell.

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Membership News

Of the many tasks assigned to Membership Secretaries over the last decade, the most taxing are undoubtedly  the new EU GDPR – General Data Protection Regulations. They are meant to ensure the secure collection, storage and usage of personal information and although there are supposed to be derogations for some small societies, the usual ‘one size fits all’ prevails.

The legislation is impenetrable and written for lawyers and although most of the data processing  by membership organisations such as ours can be done on the basis of ‘legitimate interest or ‘proper performance of the contract with the data subject (You!), we are taking all precautions and asking all members and contacts to opt-in to receiving mail from us.

It may seem obvious that we need your CV or similar to enable us to grade you and your email address to contact you, but we need to make sure that it is freely given. We are also taking steps to ensure that your data is kept safe and from now on it will be stored in a portable disc drive kept of-line and all paper based systems kept in a locked cabinet.

All members have access to their data at all times through the website, via a password, and can make changes at any time. We only reserve the right to audit photographs!

We have always held historical data going right back to the founding of the Institute, including mundane items like council meetings and although they are all paper based, they are for the use of members and were on display at our 40^th anniversary dinner.

So – a new dawn awaits on the 25^th of May and if you want to find out more about it, you can access information at the Information Commissioners Office.

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Institute of Circuit Technology Meriden Seminar,

Meriden, UK, 13^th March 2018

Pete Starkey

Bill Wikie: Technical Director ICT

The Institute of Circuit Technology returned to Meriden, traditionally regarded as the centre of England, for its Annual General Meeting, which was followed by a technical seminar of five presentations, introduced as ever by Technical Director Bill Wilkie.

Steve Payne: ICT Vice-Chairman and Manager of European Operations for the International Electronics Manufacturing Initiative (iNEMI)

Steve Payne, ICT Vice-Chairman and Manager of European Operations for the International Electronics Manufacturing Initiative (iNEMI), gave an introduction and brief overview of the organisation in his presentation on future opportunities for PCB technology. He explained that iNEMI was a not-for-profit R&D consortium of leading electronics manufacturers, suppliers, associations, and government agencies, that encompassed all market sectors and technologies in electronics manufacturing, from design and modelling through to test, as well as recycling and sustainability issues.  A principal objective was to roadmap the future technology requirements of the global electronics industry and to identify, prioritise and eliminate the gaps by engaging in timely R&D projects. The iNEMI roadmap represented the global collaboration of leading experts representing all aspects of the electronics industry, with a ten-year outlook that provided a perspective on technology trends and challenges. A unique characteristic of iNEMI projects was that they could leverage skills and resources across market sectors and throughout the supply chain.

Payne examined some of the issues associated with miniaturisation and high density interconnect, embedded components, optical PCBs, flexible and stretchable circuits, and discussed the role of Industry 4.0 and the Industrial Internet of Things in the PCB fabrication sector. He commented that although most individual PCB fabricators had limited R&D resources, they could benefit from participation in collaborative projects to make the most of their collective expertise, and this would be a topic he would raise for discussion at the forthcoming PCB Fabricators’ Group meeting. 

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Dr Neil Chilton, Technical Director of Printed Electronics Ltd (PEL)

Dr Neil Chilton, Technical Director of Printed Electronics Ltd (PEL), gave a market overview of printed, conformal and flexible electronics, discussed PEL’s activities and areas of expertise, and introduced some novel techniques that used printing to create electronic devices or combined PCB technologies with printed electronics and additive manufacturing to produce “unconventional” circuitry and interconnects.

The market for “large area electronics”, a classification which included printed electronics and organic electronics, was expanding rapidly, particularly in the areas of displays and lighting. There was a substantial demand for printed sensors, predominantly mass-produced glucose test strips, but continued growth was forecast for non-biological sensors, principally photo-detectors, gas sensors and temperature sensors. In stretchable electronics, the key innovation areas were stretchable inks, flex-to-rigid connections, and sensor structures and materials.

Dr Chilton discussed opportunities for nano-metal inkjet printed circuits in stretchable and conformable electronics technologies, where a principal advantage was the elimination of conventional substrates by printing directly onto pre-existing surfaces. A limitation was that the circuitry was usually thinner, more fragile and more resistive than conventional electronics, and could not carry significant current. However, if inkjet was used to print a seed layer, more substantial conductors could be built up by electroless metal deposition. Screen printing was an alternative technique for the manufacture of sensors and ultra-thin flexible circuits, and gave access to different materials and more robust structures. In aerospace applications, printed and large area electronics offered weight savings and opportunities for thin, long form factors.

Inkjet nano-particle inks were generally of very low viscosity and low metal content, and even on high quality substrates, conventional piezo-electric printers could not approach the resolution that could be achieved by photolithography. And it was difficult to print on curved surfaces. One of PEL’s innovations was their “3D Surface Printer”, with a programmable Z-axis, for non-contact digitally printing thicker deposits of viscous high-metal-content inks onto three-dimensional objects. And a five-axis system had now been developed. Dr Chilton showed examples of printing on cylindrical pre-forms to create antennas for a defence application. It was also possible to use the technique for producing embedded electronics.

But at the other end of the resolution scale, a process for printing one-micron track and gap features was now available, known as “Super-Fine Inkjet”, with an electro-hydrodynamic system for generating drops in the sub-femtolitre range.

Dr Chilton stressed that printed electronics would not replace PCB technology but offered complementary production methods to enable new form factors, using a combination of new technologies and adaptations of established techniques.

ICT Chairman Professor Andy Cobley, leader of the Functional Materials Research Group at Coventry University.

ICT Chairman Professor Andy Cobley, leader of the Functional Materials Research Group at Coventry University, gave an introduction to the ‘MATUROLIFE’ project, funded under the Horizon 2020 programme, with over 20 collaborating organisations from across Europe. The project aimed to produce innovative assistive technology for older people, for example alarms and tracking devices, that would achieve better integration of sensors into fabrics and textiles, allowing designers to create high-added-value products that were not only functional, but also more desirable and appealing to older people as well as being lighter and more comfortable. Creative artists and fashion designers were included in the research team to facilitate design-driven innovation.

Conductivity and electronic connectivity in textiles could be achieved by encapsulating fibres with metal and prior work with the National Physical Laboratory had established a selective metallisation process, using a silver nanoparticle catalyst followed by electroless copper. The aim of current project work by the materials science collaborators was to replace the silver nanoparticle catalyst with a copper nanoparticle catalyst and establish a sustainable selective metallisation process for textiles. In parallel, the design management approach was to engage end users in the product design process with the aim to achieve aesthetically pleasing and fashionable assistive technology for older people.

The broader project objectives were to produce superior smart textiles and develop final finishes to improve their long-term electrical conductivity, to build a small-scale pilot line for the development of selective metallisation manufacturing concepts on textiles and fabrics, and to manufacture and validate assistive technology demonstrators in furniture, clothing and footwear.  

Andre Bodegom, Managing Director of Adeon Technologies

Andre Bodegom, Managing Director of Adeon Technologies, discussed new developments in automated optical inspection (AOI), with particular reference to traceability. Commenting that the technology gap between IC substrates and PCBs was progressively narrowing, he listed the challenges to the developers of today’s AOI systems: maintaining design-embedded intelligence and key feature information, automatically attaching specific inspection parameters, and handling the data processing associated with high-mix quick-turnaround work, whilst maximising equipment utilisation by combining applications, and communicating inspection, measurement and traceability information to the outside world.

With the aid of a series of examples and screen-shots, Bodegom explained the concept of “parameterised” optical inspection, beginning with the software capability to read the original CAD data from any source and apply smart logic to filtering and zoning the attributes, identifying different materials and technology levels per layer, predicting magnification levels and automatic adjustment of greyscale and illumination with respect to the variety of track-widths, pad types and features, and identifying types of defects and their impact, enabling a straightforward and user-friendly error-free set-up for the operator.

Industry-leading equipment was capable of automatically identifying the particular layer of a particular job by barcode or QR code, and could set-up, calibrate and register on-the-fly, with full automation an option, and scan and report defects according to pre-set technology levels and defect sizes, with on-line or off-line verification. Add-on metrology options could enable accurate dimensional measurement as well as height measurement and 3D profiling.

All results from inspection and verification could be collated in a central database, integrated into the factory IT system with open-platform logic, and accessed via any web browser on the same network, with the facility to maintain complete traceability and to let the customer generate any defect classification report he might need.

Graham Naisbitt, Managing Director of Gen3 Systems Ltd

Graham Naisbitt, Managing Director of Gen3 Systems Ltd, presented a new approach to the ionic contamination testing of electronic circuit boards and assemblies. He discussed the limitations of the traditional method measurement of ionisable surface contaminants by resistivity of solvent extract. (ROSE), which had originated back in the 1970s and is documented in IPC-TM-650, method 2.3.25. Although the technique had originally been intended for use as a process tool, it had been widely adopted as an acceptance test for cleanliness, in military and commercial standards. The requirement was to achieve better than the ionic equivalent of 1.56 micrograms of sodium chloride per square centimetre of extracted surface.

Naisbitt commented that the 1.56 micrograms limit was arbitrary, and did not correlate with environmental field reliability, especially considering the wide range of complexity of assemblies, the variety of components, feature sizes, number of solder joints, flux types and materials. Moreover, the test did not detect non-ionic contaminants which might contribute to reliability issues, and the conditions of test could extract ionic species from deeper within the material than the surface, which in real-life would never appear as free ionic material or affect reliability, but could be interpreted as false defects

Of more recent times, these limitations had been acknowledged and there had been a desire to change the approach to contamination testing, with the aim to use the dissolvable ionic material as a process indicator. A joint exercise by Robert Bosch and Gen3 Systems had demonstrated the validity of the process monitoring approach, and the consistency of measurement had been validated statistically by a gauge repeatability and reproducibility analysis across a number of sites world-wide. Sufficient flow rate, CO₂ compensation and sensitive conductivity measurement had been shown to be necessary to achieve consistent performance. This test was of short duration and run at room temperature, and was known by the acronym PICT (Process Ionic Contamination Testing). Naisbitt described in detail the work that had been done to optimise the PICT test process, and to compare it with the equivalent ROSE procedure.

The IPC ROSE working group had produced a white paper recommending that the technique should no longer be considered a cleanliness method but rather as a process indicator, and this recommendation would be included in Revision H of IPC-J-STD 001, classing PICT as a process control method. Naisbitt was leading the UK team working on the development of IEC 61189-5-504, which would similarly address previous difficulties and shift the emphasis from cleanliness assessment to process indicator.

Professor Andy Cobley wrapped up the proceedings, thanking all of the participants, and the evening concluded with the customary convivial networking session.

Pete Starkey

I-Connect007

March 2018

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Metallisation of Textiles to make Urban living for Older people more Independent and Fashionable

The MATUROLIFE Project.

Professor Andy Cobley, leader of the Functional Materials Research Group at Coventry University and ICT Chairman

Authors – Prof Andrew Cobley, Dr Daryl Fox, Dr Golnaz Taghavi Pourian Azar

The Functional Materials Group, Coventry University, UK

Electronic or ‘smart’ textiles represent a potentially high growth area for electronics manufacturing. There are a number of ways to make textiles and fabrics conductive including knitting or weaving in conductive threads or metal wires or printing conductive inks onto such materials. However, these approaches have their drawbacks. In addition, in many cases, it is arguable whether such approach can produce electronics that are truly integrated into the textile as conventional metal wires change the feel and drape of the material and make them stiff and less flexible. Simply attaching electronic components to a textile makes them heavier and uncomfortable to wear.

The MATUROLIFE (Metallisation of Textiles to make Urban living for Older people more Independent and Fashionable) project led by Coventry University (UK), which is funded by the European Commission and involves 20 partners from 9 countries, takes an alternative approach to introducing connectivity to textiles and fabrics. Building on collaborative work carried out between Coventry University and the National Physical Laboratory, the project will use processes common in PCB manufacture to produce conductive ‘smart’ textiles. In MATUROLIFE, catalysts will be developed that can be selectively deposited onto textiles and fabrics enabling subsequent electroless plating processes to fully coat fibres within the textiles. Previous work has shown that only a relatively thin coating of electroless copper is required to produce highly conductive textiles. By coating the fibres in the textile with copper, a truly multi-functional material can be produced. The feel and drape of the textile is maintained with very little increase in weight whilst the material can still be bent and twisted in the same way as a conventional textile. Early results from the project have shown that a conventional electroless copper plating process typically used in PCB manufacture (Conditioner, pre-dip, Catalyst, Electroless Copper) can be used to successfully metallise a variety of textiles and fabrics. Figure 1 shows an SEM of a polyester material with a uniform coating of electroless copper.

Figure 1. Scanning Electron Microscope (SEM) image of polyester material coated in Electroless Copper using electroless copper process chemistry supplied by AGAS Electronic Materials Ltd

Methods will be developed to selectively deposit catalysts that will initiate electroless copper plating. In this way circuits and electronic connectivity can be introduced to textiles and fabrics. A MATUROLIFE test pattern has been developed by project partner Printed Electronics Ltd and is shown in Figure 2 below.

Figure 2. The MATUROLIFE Test pattern printed by Printed Electronics Ltd.

The MATUROLIFE project aims to use this approach to produce ‘smart’ textiles that can be used for Assistive Technology (AT) for older people. With an increase in the ageing population across Europe there is a huge and growing demand for AT. However, such devices are not designed with fashion, aesthetics or discretion in mind and are often obvious marking the person out as vulnerable and ‘older’. Obtaining the opinions and desires of older people will therefore be central to MATUROLIFE. The project will utilise a design management approach embedding creative artists and designers and their methods throughout the project. Product development will ensure embedding of emotional design principles and adoption of a co-creation approach. Thus, older people will influence the design of AT ensuring it is functional, meets their needs and requirements and is aesthetically pleasing and desirable.

The MATUROLIFE project brings a unique multi-disciplinary approach to research in that it will bring together electrochemists, materials scientists and experts in electronic manufacturing processes with creative and artistic designers to produce smart textiles and fabrics that could revolutionise AT for older people, enabling the production of more discreet, and aesthetically pleasing AT with improved functionality making their lives easier and more secure.

More, and regularly updated, information on the project can be found at our website maturolife.eu. You can also follow us on Twitter @maturolife.

The author would like to thank the European Commission for funding this project (Grant Agreement No 760789) and our partners: AGAS Electronic Materials Ltd, Printed Electronic Materials Ltd,  Eurocarers, CTCR, UPH – Siedlce, Pitillos, Luksja, IFTH, ITAINNOVA, Bertin Aubert Industries, Muebleconfort SL, Emo Design, Plasmachem GmbH, Univerza V Mariboru, ISN DOO, Age Platform Europe, GEDS, IPM2, Sensing Tex SL.

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IPC-J-STD-001 Section 8

Change Rationale for Cleaning Process Requirements for Soldered Electrical and Electronic Assemblies

Graham Naisbitt

Graham Naisbitt, Managing Director of Gen3 Systems Ltd

The requirements in this section are based on 25-year-old data, and the testing requirements are outdated for today’s technology.

At the IPC Standards Development meeting in Rosemont, Il, it was unanimously agreed to accept a major change to Section 8 of IPC-J-STD-001 that includes the following statement:

Unless otherwise specified by the User, the Manufacturer shall qualify soldering and/or cleaning processes that result in acceptable levels of flux and other residues. Objective evidence shall be available for review. See J-STD-001 Appendix C for examples of objective evidence.

The use of the historical 1.56 ug/NaCl equivalence/ cm2 value for ROSE, with no other supporting objective evidence, is not considered an acceptable basis for qualifying a manufacturing process (see IPC-WP-019).

Why the change? Consider this extract from the Associated White Paper:

It is the position of the IPC committees that the value of 1.56 μg NaCl equivalence per square centimeter should be considered as obsolete for the following reasons:

• This test methodology was originally developed in the 1970s; it was never intended to be used as a cleanliness test, nor as a test for product acceptability, it was only intended to be used as a process control method

• The use of the ionic contamination value as a measure of product acceptance was the result of a US Department of Defense desire to implement a pass/fail criteria.

• This ionic contamination value, and those derived from them, were originally developed for high solids (35% solids) rosin fluxes and ozone depleting chemical (ODC) cleaning. The flux chemistries and cleaning solutions used today are completely different from those used when the ROSE limits were established.

• Modern assemblies are simply too complex in terms of residues to have a single “one size fits all” cleanliness criterion.

• There is mounting evidence that as CCA component density increases, so does the sensitivity of the circuit to ionic contamination. Modern circuit assemblies have far greater component densities than found in the 1970s. This also means that residues that had minimal impact on 1970s component technologies can now have a significant impact on component reliability.

• For many assemblies, ROSE testing is no a longer sufficient test regimen to adequately predict acceptable levels of ionic residues. IPC has compiled a list of technical presentations showing the inadequacy of ROSE to predict ionic residues for high performance electronics (see last page of the document).

• It is recognized that ionic residue testing is critical for reliable circuit function and so the ROSE test has continued in use until a more suitable alternative can be identified and implemented.

Coincident with this change, is a new test method from IEC:

Process Ionic Contamination Testing (PICT) IEC 61189-5-504 Scheduled for publication by 2019 or sooner.

• • Cleanliness assumes you have tested all possible contaminants on the board. You can’t do this!
• • Process control assumes you are removing the same contaminants every time. You can do this reliably and reproducibly!

As this is a process control test, it naturally follows that this should be completed as quickly as possible, especially if it is in use on a high-volume production line. The maximum test time should not exceed 15 minutes.

The recommended test is a Closed-Loop technique involving a mixture of 50% De-Ionised water and 50% IsoPropyl Alcohol (IPA or Propan-2-Ol)) Although a mixture of 75% IPA and 25% water has been more commonly used (IPC Tests), this 50/50 solution doubles the sensitivity of the test.

Water, of course, dissolves salt (NaCl) whereas the IPA is used to aid the dissolution of organic salts so as to release encapsulated ionic materials. It plays almost no role in the ionic dissolution process, as it is very weakly ionic compared to water.

The more IPA in the solution, ionic contamination testing becomes less sensitive. If there were no alcohol-soluble/water insoluble components in the contaminant porridge, then such testing would achieve maximum sensitivity with 0% IPA. This is why the UK and some other defence standards specify 50% IPA and not 75%; it doubles the sensitivity of the test as there is double the quantity of water, which is all that counts.

When conducting a test, it is the presence of the now dissociated ions that increases the conductivity of the test solution.

The measured conductivity is the sum of the conductivity from the water and the conductivity from the sodium and chloride ions. It is expressed as μg/cm² ≡ NaCl

This does not imply that the contamination is NaCl, but that it exhibits a level of conductivity equivalent to that of the expressed amount of NaCl if it were in solution instead of the ionic soil.

There are some who suggest that heated solution to around 400C be used. This is primarily because of the fundamental misunderstanding that this is a “cleanliness test” which it is not.

Apart from the obvious health and safety risks associated with heated alcohol, pure water has equal numbers of hydroxyl and hydronium ions at all temperatures. The exponent of the ion concentration falls from ~15 at 0°C to ~12 at 100°C. In other words, the warmer the water, the lower the ionic concentration, which directly affects the test results.

Some contaminants, that might be sub-surface, may take hours or days to asymptote. Of course, to have a test that long would become increasingly inaccurate, because CO2 absorption, that should be compensated for in these instruments, would be greater than the dissolved leachates, and the accuracy would be lower than a real 15 minute test.

The test system has to deal with the influence of CO2 from the air above the test solution in the tank as well as the leachates from the assembly laminate and, for optimum results, the ratio of test solution to the specimen surface area needs to be 1cm2:100ml.

Unlike the current IPC-TM-650 Method 2.6.25, PICT instruments SHALL show acceptable Gauge R&R.

This test protocol has achieved 6-Sigma control verification.

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Printed, Conformal and Flexible Electronics

Neil Chilton PhD

Technical Director – PEL

Dr Neil Chilton, Technical Director of Printed Electronics Ltd (PEL)

It is now more than 10 years since Printable Electronics (PE) moved from academic research activity and into a commercially-viable, but often development-scale, form and in many areas a transition to high volume commercial-production has not yet been fully made. But both the real potential and the expectation remain high: incorporating PE components and systems can revolutionise product design and function.

Over the last few years the manufacturing equipment, material portfolio and production capability available within the Printed Electronic and Large Area Electronics community has improved greatly. But at the same time, it must be remembered that conventional subtractive and lithographically-formed electronics offers an exceptional wealth of capability and resource. For example, PCB interconnection density will remain in advance of the production capability of most printable interconnects for many years to come. Therefore, it is essential to understand that printable electronics is not a competitive industry to PCB or conventional electronics and is better understood when seen as running in parallel with conventional manufacturing – and each can embrace the other to best achieve potential gains.

In this article I will focus on activities in PEL and the wider community concentrating on areas where conventional PCB would be harder to implement – specifically looking at directly-printed, flexible and conformal electronics. I will outline current capabilities and highlight areas where the field has the potential to gain most commercial success.

This article is based on a presentation given at the EIPC winter conference (Lyon 2018) and the ICT seminar (Coventry, 2018).

About PEL

Printed Electronics Limited (PEL) is a UK based manufacturer sited at the Amphenol Invotec facility in Tamworth UK, and with a sister site in Cambridge. The business is manufacturing-based with a core focus on process and product development involving printing and electronics (not always solely printed-electronics); specialist-equipment and materials sales; bespoke ink formulation and industrial scale up. PEL has been operating for more than 12 years and has a team of experts with a deep understanding of both electronics and printing technologies. In recent years a significant focus has been placed on combining Printed Electronics (PE) with Additive Manufacturing (AM) processes. PEL is also a member of the EU Graphene Flagship (https://graphene-flagship.eu/project/Pages/Consortium.aspx ) programme and is working with 2D materials in areas of both electronic and structural enhancement.

We are often asked to develop and produce low to mid-volume specialist or “unconventional” circuitry and interconnects on a fast-turn. These are systems where the form and function of the part dictates that a PCB alone would not be appropriate, and often these printed elements have a lower level of complexity than a PCB; two or three layers of connection is common, but few printed solutions would be practical with more than, say, 6 layers, this is because yields significantly drop when adding further layers. The reason for this is that printed dielectric layers are often, for reasons including pin-holes, less capable than their equivalent in the conventional manufacturing world.  Recognising that printing alone can limit functional capability means that we regularly make use of hybrid electronics: coupling conventional components with Printable Electronics.

What’s in a name?

With the name and domain of Printed Electronics we are in a fortunate position that we are found quite easily on web searches. However, there may still be some confusion over names used within this sector. Together with PE, the names Organic Electronics, Plastic Electronics and Large Area Electronics are all used. Essentially these are all aliases for this branch of electronics. The name organic electronics is perhaps used less widely now, partly because it is not straightforward to manufacture n-type semiconductors with solely organic materials and both p and n type are essential for CMOS structures. The name Large Area Electronics  (http://www-large-area-electronics.eng.cam.ac.uk/what-is-large-area-electronics/) is possibly the most relevant in this field because the differentiator here is not so much the type of material used (organic, inorganic etc), nor is the method of application (printed or otherwise), instead it is the fact that this branch of electronics is one where the form factor is distinct from the panel-based approaches of “conventional manufacturing” in PCB, semiconductor or PV. The important ability is often to be able to manufacture in large format (even if the final part is smaller).

Figure 1 Forecast for Printed, Flexible and Organic electronics. Courtesy of IDTechEx (www.IDTechEx.com)

What is the market?

In the PCB industry the market size is known to a high level of accuracy thanks to the well-established works of Dr Nakahara, Walt Custer and others in this area – and all numbers are verifiable through import and export tax coding records etc. The true market size for Printed, Flexible and Large Area electronics though is subject to a little more interpretation.  For this article we have been given the kind permission of industry specialists IDTechEx to use some of their analysis. IDTechEx report (Figure 1) that the available market for this sector is as high as $29bn. However, it is important to note, as IDTechEx also do, that this headline number includes OLED mobile phone screens (which are made almost solely using semicon fab methods), diabetes test strips (which are true printed electronics but are not new since they have been made using roll to roll printing for many years now) and the sales of conductive ink (which in addition to glucose test strips is used extensively in the manufacture of screen-printed capacitive touch interconnects on glass). 

But even excluding the headline revenue elements noted above that still leaves a market that is in the billion-dollar range.

Figure 2 IDTechEx forecast for Printed Sensors, an area where there is widespread agreement that growth is  occuring

Now, to look for where the growth is expected to occur. Figure 2 shows the expected growth of medical and non-bio sensors over the coming years. Printed sensors open up a market that currently doesn’t exist. An analogy that could be used is that of smoke detectors in the home. 40 years ago, they were expensive and therefore rarely used in the home; now they are ubiquitous. Low cost sensors for pollutant and other gases will allow a similar growth to occur especially in industrial and medical monitoring use. But gas sensing is only one area where printed sensors are likely to be used. Another growth area is expected to be adding sensors to parts that currently have none – for example adding touch sensitivity to the surface of industrial robots or adding sensing capability to prosthetics. Here it is the form factor rather than the manufacturing method that is differentiating the devices.

On the topic of form factor, this is – in PEL’s view – the most important differentiator to understanding where this market will head. Simply put, if you can adequately integrate your electronics using either rigid, flex or flex-rigid PCB then it is unlikely that you need to look outside of conventional electronics. However, if the form factor is somehow compromised by the fixed shape of the underlying PCB (inside its case) then this is where PE approaches can bring major benefit.

Figure 3 Structural Electronic – just one area where form- factor is demanding a change to the physical structure of the electronics used

So, you have an interest…?

Assuming then that the ability to create interconnects or electronic sensors in some sort of unconventional format is useful for your product, the next step is to consider how to go about forming these. It is also worth noting here that PEL works mainly in interconnects -and does not currently have a core capability in directly printed semiconductor, PV or gas sensors, so we will not cover that aspect of printed electronics in this article.

One area of interest to PEL and partners is aerospace where lightweight circuits can provide significant commercial benefit. In aerospace SWaP (Size, Weight and Power) is a widely used acronym for critical design considerations. Enhancing any of these elements makes a material difference to performance. Some areas of interest that our aerospace partners have shown are in directly-printed interconnect structures, long and lightweight cable replacements, sensors and embedded circuitry also together with some wearable applications.

Figure 4 Inkjet printing of circuits

Figure 4 shows two examples of directly (inkjet) printed circuit structures - one flat and one curved. The helmet application was done for light-weighting reasons: removing the weight of the circuit board itself brings a significant potential functional improvement. If you are now thinking “well, how heavy can a flex PCB be?” I need to add one more comment – this helmet is designed to be used by fighter pilots at up to 9G hence every gram matters up to nine times more.

thinner than conventional traces you need to consider the material that is actually printed by an inkjet head.

All inkjet heads – whether it be the one sitting on the home/office desk or one printing gold sensors for medical applications – print a fluid ink[1]. The ink needs to have a low viscosity in order to be ejected from the head. The viscosity is slightly dependent on the head type but is around that of semi-skimmed milk – so not particularly viscous at all. For a metal-bearing ink, albeit with nano-particles of metal, the only way to achieve such a low viscosity is to have an ink where most of volume of the fluid is not metal but is carrier-solvent. A typical 30%-by-weight metal-loaded inkjet ink contains perhaps 95% solvent by volume. That means that most of the physical volume of deposited material needs to be evaporated away, leaving behind a relatively thin layer of metal. Typically, metal-inkjet deposits around 250nm of metal per printed layer of deposited ink. This low solid-metal thickness is specific for low viscosity inks like inkjet and flexo. Screen print and dispensing metal pastes contain much higher solid content (perhaps up to 85% metal) and, as evidenced by their use in thick film manufacturing, can lay down a much thicker trace than inkjet in a single pass.

It is possible to produce thicker metal layers using inkjet printing, and there are two predominant methods to doing this – the first method is to print many layers of material on top of each other, and the second is to print a thin layer but use a subsequent electroless plating process to increase the thickness of metal. Multilayer direct metal printing is the method employed in the Nanodimension Dragonfly PCB printer (https://www.nano-di.com/). And, plating with electroless copper after printing a catalyst is the method used by InkjetFlex© (www.InkjetFlex.com).

Printing multiple layers of metal ink is not as simple as it may sound. Because inks are fluids and readily mobile, to do this successfully requires ingenious engineering as well as excellent printing and ink qualities. The approach used is to print, to dry (and sinter) and to repeat many times until the required thickness is built. This is a process that can take hours to complete, meaning that the ink used need to be excellent and the engineering platform needs to be exceptionally stable to ensure that the print quality is as good on the last printed layer as it is on the first.

The InkjetFlex® process is one that has been available for many years and is now sited at CPI in the North East of the UK. This process uses inkjet printing – but doesn’t directly print metal inks. Instead it uses an array of inkjet heads on a Roll to Roll platform to print a catalyst layer which is then e-less plated, again in roll to roll format. This is unique in that it can produce circuits that are extremely long, potentially at km lengths. Currently the process is able only to produce single layers of circuitry but for sensors or other simple interconnects it has a genuinely disruptive capability. An example of a project where PEL and CPI worked on Inkjet Flex is in a Square Kilometer Array project with the university of Malta (https://www.uk-cpi.com/case-studies/cpi-helps-to-construct-worlds-largest-radio-telescope).

[1] At the time of inkjet printing all inks are low viscosity fluids. We don’t cover here, but there are some very useful hot-melt or phase change inks that are in common usage in etching industries including PCB.

touch screens as well as in the newer areas described here. When we started PEL in 2006 we had the target to do everything with digital additive manufacturing methods (inkjet etc), but over the years we have come to the realisation that if an analogue process is not broken there is no reason for us to try to fix it. In fact, PEL now do as much screen printing as we do inkjet printing and we sell and support both screen print and inkjet equipment in our sector.

Conductive screen-printing is a highly capable process underpinned by an excellent commercial range of metallic inks with long history. Printing a thick (perhaps 10um) layer of metallic ink with screen methods is a simple single-pass process. The robustness and conductivity of that thicker layer is often a desirable characteristic. What is clearly less desirable in the screen-print process is that you need to make a screen (or stencil as it is sometimes called). The process of high quality screen manufacturing is not trivial and requires a number of analogue steps. This is the reason most PCB facilities globally have moved to inkjet-printed legend over screen printed legend.

It would therefore be very useful to be have a capability to deposit thick screen print style inks but using a digital direct deposition printing method. It is that need that, back in 2012, started the development process for PEL’s 3DSP (3D Surface Printer), a printer designed specifically to deposit thick paste inks from digitally-controlled non-contact print heads.

Figure 5 Examples of parts printed using PEL's 3DSP multi-axis print system

The PEL 3DSP platform is a non-contact viscous paste printer with a large 600 x 500 x 250mm print area and a four-axis motion controller. We have used it for printing antennas, FSS (frequency selective surfaces) and similar patterns onto various external surfaces on parts. The system has been designed for both conductive printing and material deposition. In the area of material-deposition we partner with a UK 2D-material manufacturer to improve structural strength of industrial composites by directly printing.

For conformal systems with five and more axes of control PEL partner with Neotech AMT GmbH whom have a system which allows printing of, for example, mobile antennas directly on casing elements.

Our 3DSP system is a conformal printer, meaning it prints on the surface of existing parts. But printing only on the surface means that the circuitry then needs to be further protected by additional coatings. To truly embed the electronic interconnects inside a 3D printed object during its manufacture, PEL are partners in an Innovate UK funded project called IMPACT which will further develop our print head system in collaboration with UK 3D Printer manufacturer CEL, Iterate Design and Warwick University’s WMG. The IMPACT project will deliver a unique large format FDM print platform that incorporates conductive deposition concurrently with the 3D printed parts.

I have argued that form-factor is the main differentiator for printable and additively manufactured electronics – and nowhere is that more true than in wearable electronics. By wearable here, I do not mean items of small rigid electronics in the form of a watch, or a health tracker, I refer to circuits that need to be flexible in the same way that clothing fabric is flexible: bendable, perhaps stretchable and certainly able to be scrunched in ways that conventional electronics cannot be (and still survive).

PEL have partnered with NEL (www.nel-ltd.co.uk), patent holder of the fabric circuit technology, for a number of years and have used this PCB-like material in a wide range of designs from flexible heaters to small displays, fashion-based electronics and LED matrix displays that have even been flown and tested on drones.

Figure 6 An example of a PEL fabric circuit - an addressable LED display array on a soft flexible fabric.

Wearable electronics on fabrics has potential to be used in areas of assisted living and healthcare, so is an area of focus. PEL are partners in three-year EU Horizon2020 project called Maturolife, led by Coventry University (https://cordis.europa.eu/project/rcn/212827_en.html). The aim of this project 

is to create electronics for assisted living in an unobtrusive form factor where the sensors are integrated into everyday garments in a form factor unnoticed by the wearer.

An extension to fabric materials is Soft Materials, a highly innovative branch of printable electronics that incorporates electronic materials that are truly flexible, stretchable and compatible with being used both on and inside the human body. A number of academic groups work in this area but the pioneering work of the Takao Someya Research Group at the University of Tokyo (http://www.ntech.t.u-tokyo.ac.jp/en/ ) and Professor John A. Rogers at Northwestern University in the USA http://rogersgroup.northwestern.edu/ stand out. These groups and commercial spin-outs have demonstrated a diverse range of processes and products including conformable membrane electronics directly applied to skin and even heart tissue, through to high volume commercial UV sensors with L’Oréal that are the size of a fingernail and can be read with a smartphone.

In conclusion, I hope I have shown that the field of Printable Electronics is wide, has unique capabilities and is not directly competitive to the existing interconnect industry. Nor is it simply a way of making lower cost versions of existing product. Instead, it is a means to realise electronic circuitry in new and very different form factors.

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PCB Fabricators Group - a new Group to benefit all who fabricate PCB’s in the UK. 

Steve Payne

Chairman of the PCB Fabricators Group

A new group within the ICT has been formed at the request of PCB Fabricators. For some years now there has not been a structured forum whereby Fabricators can meet and voice their concerns and work together for the benfit of the industry.

The Inaugural Meeting was held on 13^th March at Meriden to run consecutively with the ICT Evening Seminar. The meeting was well attended with 11 companies represented and constructive discussions were held on topics as diverse as staff recruitment, staff retention, preparations for Brexit and supply chain challenges.

The objective of the Group is to provide benefit to those companies fabricating PCB’s (in all their various forms), through supporting the development and growth of the PCB manufacturing industry and to aid the transfer of knowledge and information. Members benefit from access to business networking, market data, events, newsletters and other publications.

The PCB Fabricators Group will seek to present a cohesive and coordinated approach in dealing with other parts of industry, government and other organisations and to serve the collective needs of its members in terms of business, technical and commercial issues.

If you would like more information or are interested in joining The Group, please contact Steve Payne, (details below).

The next meeting is planned for 20^th September 2018 at Hayling Island.

Steve Payne

Chairman

PCB Fabricators Group

This email address is being protected from spambots. You need JavaScript enabled to view it.

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Industry News 

PCB Manufacturer BATM Systems SRL, Romania re-certified to ISO 9001:2015  

Waterlooville, UK, 16 May 2018 -- SCL PCB Solutions Group, a leading European manufacturer of PCB requirements, announced that its Central European facility located in Craiova, Romania has been successfully re-certified with zero non-conformities to ISO 9001:2015, the international standard for a quality management system.

The 25,000 square foot mid to high-volume PCB manufacturing plant opened in 2017 enabling SCL PCB Solutions Group to offer scaled & competitive manufacturing services to European customers as well as being closer to where multinational OEMs have their assembly plants.

About BATM Systems SRL

BATM Systems SRL is a mid to high-volume PCB manufacturing facility in Craiova, Romania and as a wholly owned subsidiary of Spirit Circuits is part of the SCL PCB Solutions Group. Officially opening its doors May 2017, it is the first volume PCB manufacturing plant to be established in Romania and offers short lead-times, competitive pricing and a fully controlled and reliable supply chain.

About SCL PCB Solutions Group
SCL PCB Group is a leading European manufacturer of PCB requirements with head offices in Waterlooville, United Kingdom. The group comprises of Spirit Circuits Ltd., Spirit Asia, Lyncolec Ltd. and BATM Systems SRL Romania. For more information, visit www.sclpcbgroup.com.

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Ventec Launches Dk 3.48 Ceramic-Filled Hydrocarbon Thermoset Material

tec-speed 20.0: Designed for the world's most demanding high frequency PCB applications 

15th May 2018 – Ventec International Group Co., Ltd. (6672 TT), a world leader in the production of polyimide & high reliability epoxy laminates and prepregs, has added to its extensive signal integrity laminate and prepreg range with the launch of tec-speed 20.0, a ceramic-filled hydrocarbon thermoset material designed for high frequency applications. tec-speed 20.0 combines unrivalled high frequency performance (Dk 3.48 / Df 0.0037), superior loss characteristics and the highest reliability with fast availability and efficient delivery through Ventec’s fully controlled and managed global supply chain and technical support-network.

tec-speed 20.0 (VT-870) is designed for the world's most demanding high frequency Printed Circuit Board applications such as cellular base station antennas, power amplifiers, LNB for broadcast satellites, automotive radar and RFID. With tec-speed 20.0, Ventec has responded to customer demands for a high-performance, reliable and cost-efficient high frequency material that also has a fast and efficient global delivery promise and dependable technical support.

About Ventec International
With volume manufacturing facilities and HQ in Suzhou China, Ventec International specializes in advanced copper clad glass reinforced and metal backed substrates for the PCB industry. With distribution locations and manufacturing sites in both the US and Europe, Ventec International is a premier supplier to the Global PCB industry. For more information, visit www.venteclaminates.com.

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Section 11

Corporate Members of The Institute of Circuit Technology

May 2018

 Weidehek 26,A1 4824 AS Breda,The Netherlands

www.alrpcbs.co.uk

Publishers Notes

The ICT Journal  - Instructions/hints for Contributors

1. As it is a digital format the length is not an issue but not too short and not too long! Short is better than none at all.

2. Article can be a paper or a text version of a seminar or company presentation. Please include data tables, graphs, or powerpoint slides.We can shrink them down to about quarter of a page. Obviously not just bullet points to speak from.

3. Photo's are welcome.

4. We would not need  source cross references

5. Title of presentation - Of course! Date, Job title of Author and Company represented.

6. An introductory summary of about 150 words would give the reader a flavour of what it's all about.

7. Style - we don't want out and out advertising but we do recognise that the speaker has a specialism in the product or process that will include some trade promotion. Sometimes it will be a unique process or equipment so trade specific must be allowed.

8. Date and any info relating to where or if this article may have been published before.

9. We can accept virtually any format. Word, Powerpoint, publisher, PDF or Open Office equivalents.

10. Also, to make it easy, the author can provide a word file to go along with his original powerpoint presentation and I/we can merge it together and select the required images.

11. A photo of author or collaborators.

I really do look forward to receiving articles for publication.

Richard Wood-Roe

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