Normal Thickness for 2Layers Flex Circuit (Adhesiveless)

Following up with the last article , here we’d like to share thickness for 2L flex circuit if using adhesiveless material.

2L FPC Flex circuit thickness (adhesiveless)

2L FPC Flex circuit thickness (adhesiveless)

2L FPC thickness using adhesiveless material

We also have other special material, such as 1mil Polyimide + 2OZ (70um) copper adhesiveless, (from Dupont). If you need more information, please contact us.

Normal Thickness for 2Layers Flex Circuit (Adhesive)

Different from rigid FR4 PCB, there’re three basic layers for flexible circuits, and various thickness of each maybe used, so people new to that area will be confused to choose a suitable thickness.

Here are four normal thickness for 2 layers (Double sided) flex circuit, and we hope it’ll be useful for the green hand:-)

2L FPC Thickness

2L FPC Thickness

2L FPC Thickness

2L FPC Thickness

As you can see, there’re adhesive in base for each four basic thickness of 2L (double sided) flex circuits, if you need more thin, then you can use adhesiveless material, and final thickness will be thinner even you use the same copper and Polyimide thickness. Please see next article (to be continued…)

How to calculate the thickness of FPCs

As is known to all, the FPCs are divided into single layer, double layers, dual access, multiayer and flex rigid.

Now I want to introduce the basic method of calculating the thickness of FPCs.

(!) single sided FPC

The constructure of single layer FPC is as follows:the board thickness for single sided FPC

25um+20um+35um+20um+25um=125um≈0.12mm

Note: the thickness of adhesive changes according to the thickness of Cu. For 1/2, 1/3 OZ Cu, we usually use 12um adhesive. But for 1OZ Cu, we have to use 20um adhesive.

That’s according to the common material. If we want the board to be thinner, we also can use the adhesiveless material to make the board about 0.8mm thick.

(2) double sided FPC

Double sided FPC means there are two layer of traces in the FPC.

The constructure of double sided FPC is as follows:

the board thickness for double sided FPC25+12+35+12+25+12+35+12+25=193um≈0.20mm