A reel of terminals passes the visual inspection and the go/no-go gauge. Six months later, tin whiskers bridge the 0.5 mm contact gap on your PCB — and the field return analysis traces back to a skipped JESD201 anneal.
In this checklist, you will verify plating material specifications, pre-treatment cleanliness protocols, post-plating anneal compliance, and thickness verification methods before the plating batch runs.
Go through every item before the batch runs.
Plating Specification
- Confirm the plating material — tin, gold, silver, nickel, or palladium — is specified with minimum thickness in microns on the terminal drawing.
- Verify the coverage zone is defined with a clear boundary: full-strip plating, selective reel-to-reel stripe, or spot plating on the contact zone only.
- Audit that the plating thickness specification differentiates between the contact zone, the bend radius, and the crimp barrel — one value for all three is insufficient.
- Confirm the underplate layer — nickel or copper flash — is specified with its own thickness tolerance, not bundled into the top coat figure.
- Validate that the tin plating specification references JESD201 for whisker mitigation or an equivalent industry standard.
- Check that gold plating over nickel is specified with a minimum gold thickness of 0.8 µm for industrial connectors per MIL-DTL-45204.
- Review the plating adhesion requirement — confirm a bend test or thermal shock test is specified, not just a tape test.
[Gate Condition]: Do not proceed to pre-treatment until the plating material, thickness per zone, underplate specification, and adhesion test method are documented and approved on the terminal drawing.
Pre-Treatment
- Confirm the cleaning process — alkaline degreasing, electrolytic cleaning, or acid activation — is specified before plating and documented in the process sheet.
- Verify that the cleaning bath concentration, temperature, and immersion time are controlled within documented ranges with periodic titration records available.
- Audit the rinse water quality specification to confirm deionized water with conductivity below 10 µS/cm is used between process tanks.
- Check that the terminals are plated within 4 hours of cleaning — any longer and surface oxidation compromises adhesion on copper alloys.
- Confirm the activation step — typically a mild acid dip — immediately precedes the plating bath entry with no intermediate drying step.
- Validate that the racking or barrel loading method prevents terminal-to-terminal contact during immersion to ensure uniform current density distribution.
[Gate Condition]: Do not proceed to plating until the cleaning protocol, rinse water quality, and maximum time-to-plate window are documented and signed off by the process engineering team.
Post-Plating Verification
- Confirm that the supplier performs JESD201-compliant post-plating annealing at 150°C within 24 hours of tin plating — demand the furnace chart record.
- Verify XRF plating thickness is measured at three zones per strip — the contact area, the bend radius, and the crimp barrel — with results recorded per reel.
- Audit the plating adhesion test method to confirm a 90-degree bend test on actual terminal geometry, not a flat coupon, is performed per production lot.
- Check that the stamped electrical terminals post-plating inspection includes a 10× magnification visual check for blistering, pitting, or nodular deposits.
- Validate that the supplier performs cross-section metallography at a minimum frequency of once per shift to verify plating thickness and underplate integrity.
- Confirm that the salt spray test duration — typically 24 to 96 hours per ASTM B117 — is specified and that the acceptance criteria are defined in the control plan.
- Review the packaging specification to confirm that plated terminals are separated by interleaving material to prevent contact abrasion during shipping.
[Gate Condition]: Do not approve the plating batch until the XRF thickness map, furnace anneal chart, adhesion bend test report, and cross-section micrograph are reviewed and filed per lot.
Audit to PO
Plated terminals passing incoming gauge can fail field-level contact resistance because bend radius XRF thickness went unverified. Kravzik runs every plating batch through a documented verification sequence — pre-treatment logs, current density monitoring, JESD201 anneal records, and three-zone XRF mapping — with all data shipping alongside your PPAP package.
Send us your terminal drawing for a complete finish audit with thickness mapping protocol and JESD201 compliance verification, delivered within 48 hours.
