Lead-free implementation

Unit 1: Background to the lead-free revolution

Contents

Introduction

The module aims have already given a clear idea that lead in electronics is “not a good thing”, and you will have gained the correct impression that this is an issue that is going to assume great significance in years to come. As your study proceeds, you will be looking at this in detail, to discover the options for change, and the ways in which lead-free can be implemented. But, before you start, perhaps we should look at the background to the legislation that is being developed and extended even as this module is being prepared.

As with all these Units, we are going to ask some fundamental questions that we want you to research before you read our model answers. It bears repeating that you will be doing yourself a disservice if you go straight to the answer. Partly this is because you will miss out on the learning experience, but, more significantly, during your researches you may well find additional information and additional insights into the issues. And, of course, there may have been some changes since we wrote the model answer – this is a fast moving field, particularly in the area of implementation.

When you are researching, look at our materials, and the comments against each, but also don’t be afraid to explore the web using a search engine of your choice. For some of the searches we will give you specific pointers as to search terms that will be of use.

So browse around, and don’t forget to make notes. If you haven’t already done so, then read what we have said about the available unit resources and on how to make best use of web resources.

Key Information

At this early stage, you will be collecting information on more than just the topic in hand. And lead-free is just one of a complex set of issues, many of which are inter-related. We therefore recommend that you make a conscious attempt not to get bogged down in detail, but just skim-read the material and extract what you need for the research topics in this Unit. However, don’t forget to make bullet notes to remind you of other interesting insights, so that you can return easily to their source.

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Environmental concerns

Web Research

What are the issues of current concern to manufacturers of electronic assemblies? If you don’t already know from your contacts within the industry, you could try a web search.

Hint: As an alternative to the ever-popular Google, you might like to try the search engine at http://www.altavista.co.uk/. This usually gets fewer hits, but the advanced search option gives much more flexibility, for example to use Boolean strings such as “electronic AND (PWB OR PCB) AND (environmental AND concerns)” and to specify a range of dates as an alternative to the ‘updated during past year’ filter.

Compare your answer with this one

Most observers in the electronics industry would rate the lead-free solder issue as their environmental priority, and in the module as a whole we will be focusing on the lead-free issue. In this Unit we are going to explore the rationale for removing lead, before looking at the practicalities. However, we are also trying to encourage you to think of lead-free in the wider contest of environmental lead pressures and the resulting legislation. Lead-free may be today’s “hot potato”, but, over time, other issues will take its place.

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Uses of lead in electronics

Only a very small amount of the world’s lead is used in electronics (a figure of 0.6% being frequently quoted), but it is extremely important in electronics and is used in many different ways, as you will see in the next activity.

Web Research

For as wide a range as possible of different types of electronic assembly, identify as many applications as possible where lead would normally be a constituent.

Hint: if you search for "lead in electronics" you will come up with a manageable number of hits (low hundreds) which will yield some applications, although there is a preponderance of material on lead-free solders. In addition you will find many comments on the drive to eliminating lead, much of it from US sources and severely critical.

You will see from the lists in the solution above that getting rid of all the lead in electronic systems is a considerable challenge, affecting much more than just the solder used for assembly.

show solution

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Background to the lead ban

Lead has been used in solders since the dawn of history, and in electronics for over 100 years. So why the ban? Research this topic before reading further.

Note that the resources are meant for browsing, and nothing about the importance of a piece of information should be inferred from its relative position in the table.

Research Topic

Why are we under pressure to ban lead?
How long has this pressure been going on?
Who or what is now driving lead-free?
Who are the interested parties?

Resource Link(s) Notes

2001 report for Environment Canada Hazards and waste from computers

 

Martin Goosey presentation on WEEE and RoHS (2004)

the reasons are illustrated on the early slides

interview with
David Bergman (2002)

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Follow the links at Sony's Corporate Social Responsibility statement, Toshiba's Environmental Protection Activities or the Panasonic Environmental Statement

Flextronics presentation from IPC/JEDEC Conference (2004)

slides 3, 4 and 13 are key at this stage

interview with
Dieter Bergman (2001)

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Farnell's page on lead facts

the introductory page on AIM web site,
(or read this page from their Lead-Free Soldering Guide)

search for "toxicity" at the Soldertec web site

interview with
Colin Lea (1999)

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browse the latest news from Soldertec,

SAMC presentation
on lead-free (2003)

 

Last revised 17 June 2004.

The pressure to ban lead is based on its harmful effects, as described at this link, and the concern is that many people will be exposed to lead from their environment, even though they may not be directly involved as a user.

The pressure to remove lead goes back over 30 years, and electronics is probably the last of the areas where change is being required. To a large extent the delay has been caused by the rearguard action to prevent the passage of the Reid Bill in the US in the early 90s.

However, a key factor is that, whilst the volume of lead is small, the volume of electronic waste is growing and its disposal is substantially uncontrolled. As reported by Alan Rae, in The costs of going green (PC Fab, March 2003), the European Union estimates that electronics contributes 4% of the municipal waste stream, and this is growing at 3 5% per annum, three times the growth of other wastes. Over 90% of this is land-filled. 400M cell phones are produced a year and perhaps 500M PCs will be obsolete by 2007.

Environmentalists are concerned, and in the past they have generated most of the pressure. However, a number of companies are now making capital from the “environmental band wagon”, and are promoting their products as being lead-free. Whilst the legislative pressures are a mandatory requirement, and set the timescale for change, there is a parallel move to promote lead-free, and indeed other environmental enhancements, as a way of gaining competitive advantage.

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Are there alternatives?

Of course you need to be convinced of the need to change to lead-free, and we would encourage you to look at the justification for doing so, as you will come across many reluctant to implement change, who believe that reliability will reduce, costs will increase and problems will multiply. Have you too met someone who has stated that they want to buy the last lead-containing cell phone on the grounds that this will have good technology, yet be reliable?!

Research Topic

Do we really need to ban lead?
Are there alternatives to banning lead?
Is going lead-free viable?

Resource Link(s) Notes

interview with
Gerry Andrews (1999)

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interview with
Ken Snowdon (2001)

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a search for "alternatives to banning lead" yielded an interesting perspective at this link – you don't have to be in electronics to be affected by lead-free!

search CircuiTree magazine for "Lead-Free PCBs Now Available"
– when you have read that, browse for similar lead-free articles

interview with
Gordon Davey (2003)

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browse the Joint Group on Pollution Prevention Lead-free Project area

Last revised 15th June 2004.

One can argue that the need to ban lead arises from irresponsibility about the disposal of electronic goods; that, were we to recycle all electronic parts, then we could continue to use lead in solders. Whilst technically and environmentally a sound proposition, this is believed not to be practicable, even though parallel moves are afoot to ensure that electronic waste is properly recycled. [Lead is, in any case, only one of the materials covered by the Directives, and the bans on materials such as mercury and cadmium are significantly easier to justify]

There is still significant doubt as to whether the case for lead from electronics going into ground water has been proven, but the technical case for continuing with lead has been lost. In Chip Scale Review in September 2001, Vern Solberg of Tessera made the comment that “As far as any health risk is concerned, most experts believe the lead-free issue is more political than real”. Those who listened to the screams of anguish on various IPC forums in 2002–03 will remember that there was considerable reluctance to accept the move to lead-free, a reluctance supported by lack of any cogent engineering analysis to provide a foundation for the environmental concerns.

However, although Solberg may well have been right in identifying the driver as being political rather than technical, the reality is that lead-free is affecting our industry, whether we like it or not. We therefore need to understand the implications of lead-free soldering, and be prepared to embrace it, even though the change may result in our producing products that are less reliable than formerly. Given the implications for both joints and components, the EDR professional has a key role to play in ensuring that the change to lead-free is managed successfully and at minimum risk to the company.

Quote

“So there are challenges and opportunities out there all round, but there are no problems. I would like to think that the electronics industry could take on this challenge in the same way that it was taken on in the plumbing industry, where the plumbers actually came about with a lead ban on their pipe-work. They grasped the nettle firmly and did away with metallurgy in joints altogether and now have the very simple push-on plastic O-ring type joints, which I think is the right way for our industry to go.”

Phil Hamilton of Celestica (1999!)

 

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Removing lead

So we need to remove lead from electronics at source, in order to prevent lead contaminating the environment. The issues we are concerning ourselves with during this Unit are focused on the printed circuit assembly, yet we should not lose sight of the major user of lead, which is the cathode ray tube. Looking at the issues here will give us insights into the general problems of recycling and design for disassembly, as well as highlighting the logistical issues involved in dealing with obsolete electronic products and the processes that have to be developed.

Lead in CRTs

Web Research

Before we look at removing lead from board and components, we suggest that you review the CRT recycling issue. A good starting point used to be the Materials for the Future Foundation web site (keep an eye out for its completion), but their basic fact sheet is still available at http://www.epa.gov/wastewise/pubs/g2gfinal.pdf.

Search for "CRT recycling" globally, or search for "CRT" at the sites run by ICER or the US National Safety Council. Or visit company sites such as CRT Recycling and Spectrum West.

How big is the problem? How severe is the problem? How do the different methods for dealing with the problem compare? Are there any general learning points from this?

Compare your answer with this one

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Lead in assemblies

Whilst CRT recycling is a major challenge, the lead in glass is very tightly bound, and in most landfill situations will not give rise to dissolved lead. However, the lead elsewhere in electronic assemblies, which is in metallic form, is more available to contaminate the environment, which is why we are being faced with a legislative requirement to make electronics lead-free.

In order to do this, we have to tackle lead in the board finish, the components, and the interconnection medium.

During your browsing you will have come across at least some mention of the difficulties, indeed we have indicated some in the last three paragraphs. Try to pull together what you know during the next activity.

Activity

Think back on what you have learnt during your browsing so far about the properties of lead-free materials, and put on paper the implications that you think these might have for fabricator, assembler and designer. If you get stuck, try a Google search using the terms "lead-free" +"implementation issues".

When you have tackled this, it’s important that you take a good look at our Implications of using alternative materials, as this is the foundation on which we will be building later in the module.

If you have really run out of time on your study of this unit, then you might like to bookmark this section and come back to it later in your studies, but please don’t forget to do so, because environmental considerations are holistic, and lead-free is not just an “island of challenge”.

Other environmental issues for electronics

In the first search, on environmental concerns, you will have discovered a number of topics that are emerging as environmental issues affecting the electronics industry. In this section, we invite you to look more closely at some of these.

Board materials and processes

Because there are a number of issues, we are dealing separately with those relating to board fabrication. Rather than just give you the answer, we would like you to do a little research first!

Web Research

Visit the US EPA site http://www.epa.gov/epahome/search.html and search for the term "Printed Wiring Board". You will find a modest number of hits, including a number of case studies. Take half an hour or so to skim through these documents and make notes on the main issues involved before reading on.

The environmental aspects of board materials and processes fall into three categories:

Overall, general opinion is that the current situation has improved, compared with that obtaining several years ago and fabricators have made substantial efforts to enhance their environmental performance, putting in place measures to meet the increasingly stringent demands of the bodies responsible.

Board fabrication involves a number of processes with health hazards and environmental implications because:

More detail is available at this link.

The two materials areas causing concern have been board finishes, with the move to lead-free, and the possible ban on certain brominated compounds used for making plastics flame retardant.

We have already mentioned that conventional HASL is lead-containing, but there is a lead-free option, as well as a number of alternative processes that are inherently lead-free. However, because lead-free soldering is itself a process with different parameters, merely exchanging one solder finish for another is by no means the end of the story. This is a topic we will be returning to in Unit 7.

More information is given on flame retardants later at this link, but indications are that the main material currently used will continue to be permitted.

The printed wiring board is only part of the problem presented by a printed circuit assembly, which first needs to be disassembled. Some of the issues involved can be seen at this link. Note that many of them are a result of the wide variety of materials used. It is not surprising that industries with a heavy recycling obligation, such as automotive, have expressed a desire to limit the variety of materials used, and encouraged the use of thermoplastics. We are not yet at a stage where thermoplastics are suitable laminate materials, but developments in this direction can be anticipated.

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Assembly materials and processes

In the assembly arena, the very first problem that surfaced in the last 1980s was the banning of the use of ozone depleting CFCs, commonly used for cleaning. As with lead-free solder, there was no immediate “plug-in” replacement, but yet a need to take action. The way in which this resulted in alternative processes and approaches to the problem can be seen at this link.

A similar problem, this time affecting atmospheric pollution rather than the ozone layer, is that of Volatile Organic Compounds. Some restrictions and reporting requirements already apply to VOCs, and a move away from them has been initiated, although far from complete. More information at this link.

A final issue relating to assembly is in the waste generated by the process, not just in terms of transit packaging but of paperwork. There is a discussion on this issue at this link.

 

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The environmental context

Lead-free is just part of a wider environmental context. Ideas that you will come across include a hierarchy of approaches, from reduce (best) through re-use, re-work and recycle. Note that ‘recycle’, often thought of as the aim of the environmentalist, is in fact the lowest element in the environmentally-friendly hierarchy. More information on the recycling of materials at this link.

Associated with environmental responsibility is the idea of sustainable development, the belief that we should engage in practices that are self-sustaining, so that resources are not used at a rate faster than they can be replenished naturally without any adverse affect elsewhere in the environment. You will find more on this topic at this link.

When assessing the environmental impact of a product or service, one has to take into account the whole of its life, from the extraction of its raw materials through production and use, to the maintenance of the product and its eventual disposal. Each product or activity has to be evaluated in the light of the resources used and the adverse impact of the environment during the whole of its life. This isn’t too far from commonsense, as two examples from everyday experience show:

There is more about Life Cycle Analysis and how it is carried out at this link.

As always, the environmental context includes a context includes a political element. Nowhere is this more evident than in the topic on the use of energy, where fiscal incentives have been applied in order to promote energy efficiency – more details at this link.

Overall, there is mounting pressure for all design activities to take the environment into account as well as the needs of the consumer and the requirement by the producer to make a profit.

Research Topic

Do any of the alternative lead-free materials have environmental consequences?

Interview with Joe Fjelstad (2001)
Interview with Joe Fjelstad (2001) video To view the video a Real media player is required.
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transcript
Resource
search alternatives +"lead ban" +electronics – one of the resources there is an article by Joe Fjelstad, based on a more extended piece in CircuiTree magazine
Resource
search "lead-free solder" +"environmental consequences"
Interview with Laura Turbini (2002)
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transcript

show solution

Last revised 15 June 2004

It is unfortunate that Life Cycle Analysis information is not yet readily available to help us evaluate the materials used for lead-free implementation. In fact, it can be very difficult to get real data on the environmental consequences of lead-free alternatives. However, an analogy from the food industry is the observation that many of the items portrayed as being “low fat” actually contain high levels of salt and sugar in order to make them palatable – we should not assume that all materials and processes apparently attractive because they are lead-free are in fact environmentally friendly.

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Reminder

If you haven’t browsed among the material on these general environmental topics, don’t forget to bookmark them so that you can return later in your studies.

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