As Flexible PCB manufacturer know that，Copper plays a vital role in the overall thickness of a printed circuit board. It also dictates a PCB’s functionality. In fact, PCB copper thickness plays an essential role in achieving standard PCB thickness. 

PCB copper thickness is achieved by spreading an ounce of copper evenly over a square foot area, which results in 1.37 mils (1.37 thousandths of an inch). Usually, all PCBs are manufactured with one ounce (10z) of copper. 

The Flexible PCB manufacturer presumes this as the right thickness for PCB applications across the board, even when the designer does not specify it. However, if the currents passing through the PCB application require the manufacturer to add the copper’s weight or the width of the trace, the total cost will increase because of the extra copper and the extended processing timeframe. The average copper thickness is 1.4mm to 2.8mm for internal layers and 2mm for the external layers. Copper thickness can be adjusted according to your requirements.