All,

The IPC-SM-782a Surface Mount Land Pattern Design standard presents the
principles of designing surface mount land patterns that are process
INDEPENDENT. This is because most designers have no control over the process
selected for assembly. Factors such as lot size, will also dictate the
soldering process. 

The issues raised, most often, are the inclusion of solder thieves. The
standard is a concensious document, with input received from many sources.
These sources have indicated that solder bridging is not necessarily design
induced. It may also be induced by control factors in the soldering process.
There was insufficient data to conclude that solder bridging was entirely
induced by land pattern design. Therefore,  no solder thieves were deemed
necessary in the recommended land patterns. However, the standard does
indicate the use of solder thieves when a specific process warrants it.

Regards,

Gary Ferrari
IPC Staff

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