How to ensure that there are no individual differences in EMC during mass production of edge boxes?

EMC consistency in the mass production of edge computing boxes depends on the batch consistency of key components, PCB processing quality, and assembly process measures. Measures include:

1. Specifying brand-name filter protection devices such as Audiotronics, strictly prohibiting arbitrary substitution, and implementing incoming material inspection. For example, the inductance tolerance of common-mode inductor CML4532A-101T is ±20%, which can be measured using an LCR meter.

2. Controlling the impedance tolerance of the PCB lamination stack to ±10%, and testing key networks using flying probes.

3. Ensuring good welding of the shielding cover during assembly, automated detection of conductive foam compression, and uniform grounding screw torque.

4. Randomly selecting one unit out of every 100 units for radiated emission verification in a 3m dark room, establishing an SPC control chart. If the impedance deviation of a certain batch of ferrite beads PBZ1608E600Z0T is found, the production line should be stopped immediately for investigation.

Through the above control measures, the EMC pass rate of edge box mass production can be stabilized at over 98%.