TTBy Tonetron Engineering Team · Dongguan Taitron Electronic Limited
Why does the same lot pass some tests and fail others?
Look for a process window, not for a defect — variance usually comes from one parameter drifting at the edge of tolerance.
Answer: when failures scatter within one lot, the cause is usually a process parameter sitting at the edge of its window, not one broken machine.
Crimp height / solder temperature — drifts during a shift.
Extrusion diameter and concentricity — a thin wall on one side changes impedance.
Braiding coverage — a few percent of coverage changes shielding effectiveness.
Diagnosis: plot the failing units by time and by machine; if the failures cluster, it is a drift, not a defect. Ask the factory for that chart, not for a promise.