Heavy Copper Flexible PCB Built On Polyimide with 2 oz Copper

(Flexible printed circuits are custom-made products, the picture and parameters shown are just for reference)

General description

This type of flexible circuit is for the application of AC power systems. It’s a 2 layer polyimide FPC at 0.3mm thick with 2 oz copper. The base laminate is from Shengyi.On head of its back is 0.1mm FR-4 stiffener. It’s fabricated per IPC 6012 Class 2 using supplied Gerber data. FR-4 as stiffener is applied on the back side.

Parameter and data sheet

Features and benefits

Excellent flexibility

Reducing the volume

Weight reduction

Consistency of assembly

Increased reliability

The end can be whole soldered

Low cost

Continuity of processing

On-time service

Quick Lead time: 3-5 days

Applications

General purpose LED soft light strip, mobile phone antenna flex board, industrial control, temperature controller soft board

Copper Foils

There are two different types of copper foils: Electro-Deposited (ED) copper foils and Rolled and annealed (RA) copper foils.

Electro-Deposited copper foils are produced by depositing copper on a stainless steel drum that rotates in a plating tank with anodes of very pure copper. The thickness of the copper foil is determined by the length of the plating process, i.e. the rotation speed of the drum. The copper is then removed from the drum and wound on a roll. The finished copper foil is very smooth on the drum side and fairly rough on the other side. The rough side has the advantage of giving better adhesion to the base

laminate.

The main characteristic of ED copper is its grain structure, which is vertical in nature because of the electrolytic process. This implies a relatively low ductility of the copper foil, thus it is not recommended for dynamic applications. The drawing below shows the vertical grain structure of ED copper.

Common foil thicknesses for flexible circuits are 17.5, 35, 70, 105 and 175 µm (0.5, 1, 2, 3 and 5 oz.).

RA Copper

This copper is a rolled and annealed copper foil produced from electrolytically deposited cathode copper, which is melted and cast into ingots. The ingots are first hot-rolled to a certain size, and milled on all surfaces. The copper is then cold-rolled and annealed, until the desired thickness is obtained.

Contrary to electro-deposited copper, rolled and annealed copper has a horizontal grain structure as shown below. The horizontal grain structure provides for much higher flexibility and a better flex life endurance than ED copper, therefore RA copper always should be used for dynamic applications.

A disadvantage of RA copper is that the bonding surface is fairly smooth, so that a relatively low adhesion is obtained. The bond, however, can be enhanced by an electrolytic copper flash without deteriorating the flexing characteristics of the copper foil.

Common foil thicknesses for flexible circuits are 17.5, 35, 70, 105 and 175 µm (0.5, 1, 2, 3 and 5 oz.)

More Displays of Heavy Copper Flex