NIHON SUPERIOR SN100C-030-16 Lead-free flux cored solder 1.6mm

1/ Alloy composition, melting behavior and why it matters

- The SN100C alloy is a tin-based, silver-free lead-free solder formulated with about 0.7% Cu and 0.05% Ni plus trace Ge to modify wetting and oxidation behavior.

- Nominal liquidus/solidus (working) range for SN100C is approximately 227°C; this is the practical melting point to use when profiling reflow or selecting iron tip temperatures.

- Effects: Cu forms intermetallic compounds with substrate metals; controlled Ni and Ge additions reduce excessive IMC growth, improve wetting and tip life, and lower visible burning of soldering tips compared with some other lead-free alloys.

2/ Flux type, activity and implications for process

- SN100C-030 is offered as a flux-cored wire with a resin-based flux designed for general-purpose soldering and repair; the flux choice affects activity, residue, and compatibility with subsequent cleaning processes.

- Flux behavior: SN100C(030) emphasizes reduced tip burning and good workability for sequential manual soldering operations, with acceptable residue characteristics for many assembly flows.

- For very sensitive assemblies or high-reliability applications, consider the specific flux chemistry (halogen content, activity class) and whether additional cleaning or a different flux grade (e.g., halogen-free) is required.

3/ Recommended soldering parameters and best-practice process

- Hand-soldering iron temperature: start testing in the 340 - 370°C range for tin-based lead-free alloys and adjust to achieve reliable wetting without overheating components. Prioritize minimizing dwell time on terminals to reduce IMC growth and component stress.

- Wave/reflow considerations: profile to ensure the solder reaches full liquidus (approx 227°C) with controlled ramp and limited time above liquidus to avoid excessive IMC thickening and thermal stress. Validate with thermocouple readings at representative PCB locations.

- Tip/flux practice: use clean, appropriate-size iron tips and maintain them regularly; resin-core wire may reduce need for added flux but do not rely on flux core alone for heavily oxidized surfaces. For poor wetting, add a compatible activator flux or perform corrective cleaning and rework steps.

- Joint technique for 1.6 mm wire: feed wire steadily, heat joint to achieve flux activation and solder flow, withdraw wire once fillet forms; control wire feed to avoid bridging and excessive buildup.

4/ Typical failure modes, diagnostics and fixes (FAQ)

- Poor wetting or dull joints: confirm surface cleanliness, increase local temperature slightly, verify flux activity (flux may have aged), or use a more active flux for problematic platings.

- Tip burning or rapid tip degradation: SN100C is designed to reduce tip burning, but high temperature or prolonged contact accelerates wear; lower contact time and keep tips tinned and clean.

- Excessive intermetallic compound (IMC) growth or brittle joints: reduce time above liquidus and avoid repeated thermal cycles; check that process temperatures and durations are within validated ranges.

- Bridging or solder balls during manual soldering: reduce solder feed rate or lower local temperature; improve flux activity balance or clean contaminated PCB surfaces.

- Flux residue cracking or contamination concerns: consider using a different flux variant (e.g., ROL0 or halogen-free) or add a post-process cleaning step; confirm residue compatibility with conformal coating if applied.

5/ Storage, handling, health and environmental notes

- Storage: keep coils in a dry, cool environment away from direct sunlight and excessive heat; reseal packaging after use to limit flux degradation and moisture pickup.

- Health and safety: although lead-free, flux fumes and soldering smoke can be irritating; ensure local exhaust and adequate ventilation and follow standard PPE and workplace ventilation practices. Obtain and follow the product SDS for handling and first-aid details.

- Environmental/regulatory: SN100C is a lead-free alternative intended for RoHS-compliant applications; verify local disposal and recycling rules for solder dross and flux residues and dispose of solder waste per regulations.

6/ Qualification, testing and process validation

- Characterize process windows for each PCB and component combination by recording: soldering iron temperature, contact time, observed wetting, fillet shape, and mechanical pull/shear test results.

- For volume production, develop a validated reflow/wave profile ensuring consistent time above liquidus and acceptable IMC thickness; perform cross-sectional metallography on sample joints to verify IMC structure and thickness.

- If particle size, oxide levels, or specific platings (e.g., Ni/Au, Ag, ENIG) are used, run compatibility tests before large-scale adoption and adjust flux or thermal profile accordingly.