Can I solder leaded components in lead-free wave soldering?
Leaded terminations cannot be soldered in a lead-free wave solder process. Lead-free solder bar will have a small amount of lead when received usually in the range of 0.01 to 0.08%. The RoHS Directive states a maximum of 0.1% lead; it does not take very much lead to surpass this limit. To avoid surpassing this limit, leaded terminations should not be allowed. There is no effective way to reduce lead content except by dilution if lead were to go beyond 0.1%. Also lead contamination can be a contributor to fillet lifting and fillet tearing. Although this is not considered a defect as per IPC-610D, further studies are required to determine the impact on high reliability assemblies. For consumer electronics reliability would not be an issue since most are not exposed to thermal cycling or thermal shock during their use.
