Issue link: https://iconnect007.uberflip.com/i/1202019
JANUARY 2020 I PCB007 MAGAZINE 75 Electrical Testing • 100% sampling (point to point, impedance, hipot test) Final Inspection • Visual, dimensional, bow and twist: "BN" sample plan 2. Month to Month: Periodic Performance Testing (PCI) • Elongation of plated copper (per copper tank: five samples horizontal and five vertical) • Tensile strength of plated copper (per copper tank: five samples horizontal and five vertical) • Purity of plated copper (per copper tank: one sample) • Surface peel strength for foil construction only: (eight samples per material type, four each from two different lots, P coupons) • Rework simulation (two B coupons per material type qualified) • Moisture and insulation resistance (two E coupons per material type qualified) 3. Year to Year: No Additional Testing Required • Summary report of the past 12 months required to verify all testing was completed. 4. Every Two Years: Capability Verification Inspection (CVI) • Thermal Shock: Two D coupons for 100 cycles per material type qualified • Two-Year Summary Report of each material type qualified: Within the two-year window, there must be test reports for each material verifying all the DLA approved attributes were compliant 5. Initial Qualification • For each material type to be qualified, all lot, monthly, and yearly tests must be completed. Summary In general, understanding the tests and the quantity to test for PWB military specifica- tion is 90% of compliance. Having learned the sample language in MIL-PRF-31032 makes cer- tification much easier. One Last Point Remember, regardless of the sample plan size or the test/inspection, when any sample fails, the sample size always defaults to 100%. In addition, when the determined sample plan size is more than the lot size, the sample is also 100%. Of course, testing/inspecting more samples than required is always allowed. PCB007 Reference 1. DLA MIL-PRF-31032C WAM1, page 49. Mike Hill is president of MIL-Q- Consulting LLC. He has been in the PWB fabrication industry for over 40 years. During that time, he participated in specification writing for both IPC and the military. Past employers include ViaSystems, Colonial Circuits, and DDi. To read past columns or contact Hill, click here or email Milqconsulting@outlook.com.