First of all we should to know what is PCB stiffeners
Usually PCB stiffeners are used to support certain areas of the flexible Printed Circuit board (also named Flex PCB).
Because most products require additional support from other components during flex aluminum PCB assembly process.
Then is the features of flex PCB stiffeners.
There were two features in flex PCB stiffeners manufacture process.
If you have looked a flex PCB stiffener, you will find all stiffeners are to strain relieve component attachment locations.
So the first feature is that provide a firm surface for mounting.
And the Second feature is that increase thickness of the flex PCB to meet, correspond to the mechanical specifications.
First PCB stiffener material: FR4/G10 Stiffeners
FR4/G10 is the most common PCB stiffener material.
By the way, some flex PCB factories also use Polyimide and polyester PCB stiffener material, we will introduce next.
The PCB stiffener hole size should be larger than through hole.
Because all customers have specific tolerances to the PCB stiffener holes.
Bonded with PSA or thermal-set adhesive
Adds rigidity to connector area or used as carrier panel.
Difference PCB stiffeners have differed thickness requires.
PCB stiffeners have many different thicknesses, and the raging from 0.01″ to 0.062″
In 4MCPCB experts’ experience, Fr-4 PCB stiffener is used when the additional thickness greater than 0.01″.
And most flex PCB designers know that typically smaller than the corresponding circuit features by 0.15″.
Secondly flex PCB stiffener material: Polyimide Stiffeners
Differentiating from FR-4 PCB stiffener fixed method, Polyimide and polyester stiffeners are fastened using an adhesive, or a heat set adhesive.
That is the reason why some of polyamide stiffener has been shedding risk.
Of course, usually experience flex PCB manufacturers can produce high quality Polyimide stiffener on the board.
Bonded with PSA or thermal-set adhesive
Used to add thickness, or add strength in high wear areas
The thickness of Polyimide flex PCB stiffener material.
Polyimide film is used when the additional thickness required is 0.002″- 0.009″. Polyimide stiffeners can have coincidental edges of the circuit outline.
Third flex PCB stifferner material: Other materials
This part content is very special for most egineers.
Because most of we have saw above two type flex PCB stiffener material.
Only in some special conditional, flex PCB manufacturers can consider other special PCB stiffener.
By the way, usually small flex PCB manufacturers can just use FR-4 or Polyimide flex PCB material.
Even some Other materials such as Stainless steel, Aluminum, Ceramic or molded plastic components can also be used as stiffeners for specific design requirements.
Standard flex circuit adhesives or pressure sensitive adhesives can be used to provide varying performance alternatives.
