Barrel V.S Base Copper

The reason why we introduce Barrel and Base Copper

In this paper, we are going to discuss Barrel V.S. Base Copper of flexible PCB.
Those are the base definition of flexible PCB.
But most of new guys don’t know much about it.
That’s the reason why 4MCPCB expert summary article.

The definition of Barrel of flexible PCB hole

The cylinder formed by plating through a drilled hole.
If you have know the raw material stack-up, circuit layers was not connected.
Only through plated copper process, there was a thin Barrel layer on the wall.

You should know Base Copper feature

Base Copper is the basic raw material to the flexible PCB board.
There were two kinds of Base Copper material.
One is thin copper foil present on one side of a copper clad laminate.
This type base copper raw material used to simple PCB board.
Then the copper foil on both sides on copper clad laminate.

Two common senses of base copper

In most new PCB guys, the base copper is very complex definition.
Some of base copper should be removed
During PCB manufacture, part of this base copper will be removed by etching.
Especially in some complex rigid PCB board, may remove more part of base copper than simple PCB board.

Simplest PCB consists of base copper

We have compressed the complex and simple PCB board.
Conductors on the simplest PCBs consist of base copper only.