PEMs can absorb moisture if not stored, handled or used properly. Moisture absorbed during storage or manufacture can lead to the so called "popcorn effect" (i.e., fracturing of the plastic encapsulant due to the rapid expansion of entrapped moisture) during the soldering process. Any ionic contaminants remaining after the manufacturing process or deposited during field usage may cause corrosion of internal metal surfaces. Moisture intrusion can mobilize residual ionic materials, initiating or accelerating this corrosion.
- Surface mount packaged PEMs require improved heat dissipation (new soldering techniques, new handling cautions).
- OEM assembly processes may require modification.
- "Dry bag" packaging may be required.
- PEM manufacturing processes typically are not negotiable[ExtChr-04h:22h]extra testing can be added, but may eventually cost more than HSMs.