| All Nelco Materials are RoHS Compliant | ||
| > | RoHS Compliance Letter for Nelco Materials (more) | |
| > | UK's National Physical Laboratory's WEEE and RoHS FAQ (more) | |
| > | Internal testing has shown all Nelco materials to be RoHS compliant. Following are some additional independent laboratory test results show key RoHS compliant materials. | |
| - | N4000-2 Multifunctional FR4 Epoxy RoHS Test Report | |
| - | N4000-6 / N4000-6 FC High-Tg Multifunctional FR4 Epoxy RoHS Test Report | |
| - | N4000-7 Low-CTE Multifunctional Epoxy RoHS Test Report | |
| - | N4000-11 Low-CTE, High-Tg Multifunctional Epoxy RoHS Test Report | |
| - | N4000-12 High-Speed, Low-Loss, Lead-Free Compatible Epoxy RoHS Test Report | |
| - | N4000-13 High-Speed, Low-Loss Epoxy RoHS Test Report | |
| - | N9000 PTFE / RF Microwave Materials RoHS Test Report | |
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Nelco Provides Several
Lead Free Compatible Materials Nelco materials include laminates and prepregs for the PCB and electronics industry, including lead free compatible materials, lead free assembly materials with high Tg, high thermal reliability and low expansion and halogen free materials for environmentally friendly application designs. |
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| > | The new Nelco Material Selection Guide provides comparative materials overview including CAF and lead-free designations for Nelco electronic materials including notations as to the lead free compatible materials | |
| > | Nelco Lead-free electronic material listing and information (more) | |
| > | Lead-Free Technical Papers: | |
| - |
Evaluating
Laminates for High Temperature Assembly (1 Mb) By Silvio Bertling As printed in The Board Authority, September 2005 |
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| - |
PWB
Dielectric Substrates for Lead-Free Electronics Manufacturing (250k) By Douglas Leys and Steven P. Schaefer As presented at IPC Expo 2003 |
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Qualities to consider when choosing a lead-free material:
Glass transition temperature (Tg), coefficient of thermal expansion (CTE)
and decomposition temperature (Td) are key data points to consider when
choosing a substrate material for a lead free assembly compatible design.
> The Tg of a resin system is the temperature at which the material
transitions from a rigid state into a softened state. Tg is the material
property typically used by the industry to compare the thermal robustness of
a laminate. Though a contributor to lead-free compatibility, Tg alone is not
sufficient alone to indicate if a material is suitable for lead free
applications.
> CTE is a measure of the material expansion below and above the Tg and
generally expressed as parts per million (ppm). A lower CTE generally
indicates increased plated through hole (PTH) reliability. A low CTE is a
strong indicator of lead free compatibility and high temperature solder
reliability.
> Td is derived by measuring the weight loss of the sample versus
temperature. Td is important when assessing thermal survivability,
particularly during high temperature lead-free processes. A material's
decomposition temperature is the temperature at which the material weight
changes by 5%. This is a crucial number to be aware of, as even a 2-3% loss
in weight, especially when exposed to multiple thermal cycles, can cause a
noticeable reduction in thermal reliability.
