Book Reviews

There are now over ten reference books dedicated to some aspect of lead-free manufacturing, two of the latest are reviewed here and hopefully my good friend Werner Engelmaier has his text on its way to my office. Jasbir Bath has gathered together a good mixture of industry and academic authors to cover each step in the path to RoHS compliance. With Jasbir working for Solectron Corporation it is fairly obvious that the main focus on the book is manufacturing and the impact of lead-free technology. It a fairly easy read so very suitable for engineers and non technical staff to get a balanced overview or the real hands on story.

Ten chapters step the reader through the inevitable overview of legislation in the US, Europe and Asia to the implementation of international standards. Each of the building blocks of manufacture are covered in a practical way including the materials and reliability. The book provides a good introduction to the issues and covers many of the issues often neglected by engineers.

Solder finishes are covered in detail by two engineers from Atotech, each finish option is covered in detail illustrating the importance of the selection. Recent surveys have shown that the change in PCB finish can often be one of the most common reasons for failure in lead-free manufacture ahead of delamination, cosmetic and via failure. Hugh Roberts and Kuldip Johal use a simple methodology to outline the finishes making a comparison fairly simple for the reader. It is fair to say that a large percentage of the text is devoted to gold processes.

Selection of laminates for printed board manufacture are discussed by Karl Sauter of SUN Microsystems; SUN have been actively involved in the discussions on materials and have spent many years investigating Conductive Anodic Filament (CAF) phenomena due to the complexity of their product design. The sections deal with the available test methods to assess materials and an interesting case study of accelerated thermal stress testing. It should be borne in mind that there are advantages to new laminates on complex products, however, not all products require high Tg materials.

The assembly section penned by Sundar Sethuraman steps the reader through the possible changes in manufacture to accommodate lead-free with the potential issues faced by any engineer tasked with product conversion. I am glad to see that Sundar highlights the need for more profiling and a review of this process. Many engineers have become a little blasé’ in the need for correct temperature monitoring. One of the surprises is that there is no section covering the growth of selective soldering and the issues associated with lead-free. It fair to say that many companies have adopted pin in hole reflow but selective is growing in popularity.

Wave soldering is deservedly given its own chapter due to the difficulty in converting the process and the many issues it raises in manufacture. Each process step, fluxing, pre-heat, handling and solder bath materials are considered along with the interaction of materials and process conditions. Advice is given on the well known wave soldering issues like fillet lifting, fillet tearing, pad lifting and the increased incidence of shorting that can occur in manufacture. Each of the process indicators is mentioned and how the IPC standards criteria change with lead-free joints.

Jasbir Bath’s first book project concludes with pages overviewing the books content and emphasising the work still needing urgent attention. Although much has been achieved in the last ten years there are many unanswered questions. In reading these final few pages it again emphasises how we have changed our whole manufacturing process but to whose benefit?

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