Differ layer rigid PCB have differing thickness

There were some customers ask the extra thin rigid PCB can we do in their first question.
Author have several answers for this question.
First situation, I will ask a customer what the layer they want to?

Due to differing layer rigid PCB have differing thickness.

For most 1 or 2 layer conventional Fr4 rigid PCB board, the extra thin can be reached 0.3MM.
But for 4 Layer rigid PCB thickness can reach 0.6MM
By the above rigid PCB thickness is the extra thin thickness, and normal PCBs are thicker than this.

Then is the type of PCB board.

As we know flexible PCB boards have thinnest thickness.
But it’s not a smart option to choose flexible PCB assembly in all projects.
In fact, thin rigid PCB also has it’s own benefit.
The first factor is low price, so you can save most cost when you choose thin rigid PCB.
Then is thin rigid PCB have shorter manufacture time, and so on.

The last factor is considered PCBA process.

As we know PCBA assembly is a very complex process, and most of finish by automatic equipment.
If you choose thin rigid PCB, can meet those requirements.
Or you should change automotive program.