Lead-Free Soldering Solutions
ACI offers solutions to customers currently using tin-lead solders that need to go lead-free. With the deadline for the removal of lead materials from the electronics manufacturing process fast approaching, ACI is able to help prepare industry to make the transition to lead free processes and materials through analytical services, hands on training and online resources available to the public. Click here to see more information available from ACI on Lead Free issues.
- Materials Compatibility
Higher soldering temperatures and alloy selections present unique challenges to electronics manufacturers wishing to implement Lead Free solders. ACI can perform material compatibility testing to determine if using Lead Free solders represent a reliability risk to your hardware.
Lead Free solders do not wet as well as their tin-Lead counterparts. ACI can perform solderability testing of components and boards, to determine if the components and boards are acceptable for use with lead-free solders.
- Component and Board Finishes
One side effect of the transition to lead-free products has been unexpected changes to component surface finishes. Such variations can result in changes in wetting performance, storage life, process efficiency, and solder joint reliability. In many cases technical data identifying the surface finish is not available. Using X-ray Fluorescence (XRF) to screen incoming lots of components for surface composition can prevent the detrimental effects of unknown changes to the surface finish.
A handful of DOD and NASA contractors are using XRF to mitigate their risk of growing tin whiskers by mandating at least 3 wt% lead in their tin-finished components. Studies have shown that tin-based finishes with approximately three percent lead or greater have a lower risk for forming tin whiskers than pure tin finishes. This has prompted DOD contractors and other companies that are traditionally exempt from the EU directives to require at least 3% Pb finishes from their component suppliers. XRF is used to screen incoming products to ensure that all tin based finishes contain at least 3% Pb.
The lead-free transition has fueled interest in alternative board surface finishes. Electroless nickel immersion gold, immersion tin, immersion silver, and OSP have been the market leaders as Sn-Pb HASL replacements. While each has its own set of drawbacks and advantages, none of these surface finishes will perform properly if the thickness of the plating is not well controlled. With the exception of OSP finished boards, the composition and plating thickness of incoming lots of bare circuit boards can be recorded prior to the first run build using XRF.
Solder Joint Integrity
Using ACI’s Scanning Electron Microscope, it is possible to determine a solder joint’s microstructure. This technique can help you determine the solder joint’s constituents, and its quality. ACI’s X-ray unit can determine the amount of voids within a solder joint.
- Solder Joint Reliability
Using the output from the lead-free soldering process, ACI can perform a series of Environmental Stress Screening tests to determine if the solder joints can survive the hardware’s intended environment. Thermal Cycling, Salt Atmosphere, Temperature Humidity Bias Life Testing, and High Temperature Operating Life are a few of the environmental test capabilities ACI offers.
- Device performance
This test methodology is performed on active components to determine if the hardware’s functional integrity has been compromised by the implementation of lead-free solders. The goal is to assure that the Lead Free soldered hardware’s operation is equivalent to or better than its tin-lead counterpart.
If you have any questions about the services listed here, or would like to request a quote for any service, please call the Helpline at (610) 362-1320, or click here to submit you question via our Helpline Form