The Definitive Guide to an Electronic Assembly Design Review / 11
When striving for optimal reliability, design engineers must consider the manufacturer's abilities and
limitations. Engineers can simulate, test and design for the perfect product, but if the manufacturer
cannot produce the completed design or procure optimal materials, design engineers may design a
product that cannot be constructed or falls short of reliability expectations.
The DfM review assesses the pad geometries used in the layout to determine long-term reliability.
Component placement ascertains the potential for shadowing during either the reflow operation or
conformal coating. This action involves analyzing the proximity of parts to PCB edges, press fit
connectors and the potential effects of improper ICT fixturing.
Measurement of trace separation assures that the voltage levels applied comply with IPC-2221.
Cleanliness and contamination are examined by looking at the fluxes, handling procedures and any
other potential source of contamination.
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Design for Manufacturability (DfM)
IPC-2221 is a generic standard for printed circuit board design
established in 1998. This standard includes requirements
intended to establish design principles and recommendations
for PCB design.
