If you are assembling PCBs, you need first. If you want implementation examples, add IPC-9199 .

IPC-9191 is the "blueprint" document, supported by sector-specific application guidelines and auditing tools: : Application of SPC to Base Materials (laminates). : Application to Printed Board Fabrication : Application to Printed Board Assembly (PBA) manufacture. SPC Quality Rating

IPC-9191 distinguishes clearly between these two concepts:

Real SPC > Inspection. ✅