Issue link: https://iconnect007.uberflip.com/i/1540184
42 DESIGN007 MAGAZINE I OCTOBER 2025 TA RG E T C O N D I T I O N when trying to define or verify the finished copper thickness of a circuit board. Modern PCB manufacturing, led by standards like IPC-6012, has shifted to dimensional copper speci- fications—micrometers (µm) or micro-inches (µin)— because these units reflect actual thickness, not inferred mass. The ounce method doesn't account for processing variation, doesn't include tolerances, and isn't directly measurable. In short, it's an engi- neering liability. To be fair, IPC-6012 doesn't completely ignore the copper weight convention. It provides refer- ence charts that correlate copper weight to nomi- nal thickness. But then it does something far more important: It defines the actual minimum finished copper thicknesses required, in µm or µin, by class and by layer type (external, internal, plated, etc.). That's the standard, and it's not just more precise; it's measurable, enforceable, and documented for the way PCBs are manufactured today. I nte r n a l l aye r fo i l t h i c k n e s s af te r p ro c e s s i n g . ( S o u rc e : T h e G l o b a l E l e ct ro n i c s As s o c i at i o n ) ▼ E x te r n a l c o n d u cto r t h i c k n e s s af te r p l at i n g . ( S o u rc e : T h e G l o b a l E l e ct ro n i c s As s o c i at i o n ) ▼