Conductor Width ??? - IPC 6012

We are having an internal debate here related to minimum Conductor Width. Can you have your QA manager review this and advise.

IPC-6012C-2010 3.5.1 Conductor Width and Thickness When not specified on the master drawing the minimum conductor width shall be 80% of the conductor pattern supplied in the procurement documentation.

3.5.3 Conductor Imperfections The conductive pattern shall contain no cracks, splits or tears. The physical geometry of a conductor is defined by its width x thickness x length. Any combination of defects specified in 3.5.3.1 and 3.5.3.2 shall not reduce the equivalent cross sectional area (width x thickness) of the conductor by more than 20% of the minimum value (minimum thickness x minimum width) for Class 2 and Class 3, and 30% of the minimum value for Class 1. The total combination of defect area lengths on a conductor shall not be greater than 10% of the conductor length or 25.0 mm [0.984 in]for Class 1 or 13.0 mm [0.512 in] for Class 2 or Class 3, whichever is less.

3.5.3.1 Conductor Width Reduction Allowable reduction of the minimum conductor width (specified or derived) due to misregistration or isolated defects (i.e., edge roughness,• nicks, pinholes and scratches) which exposes base material shall not exceed 20% of the minimum conductor width for Class 2 and Class 3, and 30% of the minimum conductor width for Class 1.

Example: 10 mil trace Then the minimum trace width of 8mils (80%) is acceptable (Class 2) Within this 8 mil trace there are pinholes. Can you then reduce the width an additional 20% of that 8 mils. 8mil x .2 equals 1.6mils addition reduction. Total reduction of trace width would then be the 8mils – 1.6 mils with the final acceptable trace width being 6.4 mils.

Is this how you evaluate conductor widths?

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