Issue link: https://iconnect007.uberflip.com/i/1500943
JUNE 2023 I DESIGN007 MAGAZINE 35 we have "intelligent data," and we are mov- ing toward data for Smart manufacturing. But CAD data output is still absolute and the sys- tems which presently create PCBs are subject to variables which affect performance. e question remains: By how much can perfor- mance vary? Limits of variation or tolerance must be calculated and declared if a PCB is going to work within a system. It is not until we get outside of the data onto the PCB fabrication drawing that we hope to see the acceptance criteria for the feature. When quality assurance inspectors can see a dimension and tolerance callout specified for the edge-to-edge distance on the PCB outline, they know the acceptance criteria. ey know the range of allowable form. If the designer has calculated the dimensional range correctly, Figure 5: DFM "speeding tickets".