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Most solder suppliers now offer a wide range of solder pastes with lead-free solder alloys. These vary in their performance and some trials to evaluate alternatives using realistic PCBs and components will be required to identify the most suitable product.

Lead-free processes require good temperature control, ideally with forced air convection ovens and a minimum of 7 zones. Throughput will be slightly reduced and there is likely to be a small increase in energy use. Some manufacturers are finding that their ovens originally used for tin/lead are suitable for lead-free but this will depend on the type of PCB, the presence of heat sensitive components, and the performance of the oven.

Solder paste suppliers will provide suggested reflow profiles for their products. The shape is different to lead-free profiles. These should be regarded as a guide for trials and optimisation of profiles will be needed. Many manufacturers are finding that where they could use one profile for most of their tin/lead PCB designs, many different profiles are needed for lead-free and, in some cases, a different profile for each design.

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