“Pattern and Drill Specification” are used
- the minimum width for copper tracks (conductors) and gap (isolation) between them both for Outer and Inner layers;
- the minimum gap (distance) between
- the minimum copper rings (
- the holes characteristic (minimum size and related production process);
- the required or needed hole accuracy (location and align registration);
- the solder mask characteristic (size of clearance related to copper lay out, minimum line size, development in holes)
- mechanical requirements
The smallest or biggest of these values determines the
For details is to be related to the MYPCBSHOP CLASSES document
IMPORTANT: all calculations are done from the provided
Notes:
a- the total or finished surface copper thickness is not a suitable parameter due to the electro-
b-
c- the Annular Ring values are normally considered for plated holes (PTH). For non-plated (NPTH) connected holes we suggest a minimum annular ring of 0.30mm (12mil): having no plated barrel, a smaller annular ring may lift during soldering or break away even during normal operating conditions.
d- It is recommended to not draw up to the limits of any class: a small margin is suggested to be kept above the classification limits. That may be used during loading data where the CAD output does not exactly match the design data due to rounding or matching errors caused by different units or grids.