The standard copper thickness is 1 oz. But just how thick is 1 oz?
1 oz = 1.37 mils
1.37 mils = 0.00137 inches OR 0.0347 mm
So, 1 oz is equivalent to 0.00137 in (0.0347 mm)
2 oz is equivalent to 0.00274 in (0.0696 mm)
3 oz is equivalent to 0.00411 in (0.104 mm)
It goes without saying, the thicker the copper the higher the cost. Aside from an increase in material cost, working with larger amounts of copper is more difficult and time consuming than with smaller amounts. The process involves pressing the copper into a flat, even layer over one square foot area on the printed circuit board.
As for the amount of spacing in between copper structures, the more the better. The following guidelines for trace/spacing minimums are recommended for optimal PCB designs:
- 1 oz – Recommended: 0.006 in (0.15 mm);
Note: 0.004-0.005 in (0.1 – 0.127 mm) is also available, but costlier.
- 2 oz – 0.01 in (0.25 mm)
- 3 oz – 0.015 in (0.38 mm)