PCB Stiffener Affect the Electrical Properties of a Board
A pcb stiffener is a piece of material attached to a flexible printed circuit board that rigidizes a specific area of the board. While they don’t hold any electrical value, stiffeners are used for a variety of purposes on flex PCBs. These include meeting thickness requirements that involve zero insertion force (ZIF) connectors and providing spot strengthening to areas of the board where components are mounted.
Stiffeners help a flex PCB stand up to a variety of stresses and handling that can damage the board and cause failure in the field. As such, they are a necessary component of any flex circuit design. Fortunately, there are different types of stiffeners available depending on the type of application. In general, a stiffener is made of FR-4 material (the same type of glass fiber cloth used in rigid PCBs). Stiffeners can also be created from polyimide or a metal such as aluminum or stainless steel.
Typically, the stiffener will be attached to the flex PCB in two ways: thermal bonding or epoxy adhesive. Both techniques have their benefits, but the method chosen should be based on the physical, mechanical, and thermal properties of the stiffener, as well as the application environment. Thermal bonding provides a stronger and more robust connection but requires specialized equipment to use. Epoxy adhesive is simpler and more cost-effective, but is less stable under high stress.
The size of a stiffener is another important factor that must be taken into consideration. The stiffener should be sized to match the area that needs reinforcement and minimize overhang. It should also be able to resist bending without deforming permanently. The stiffener should also be able to absorb and dissipate heat from the flex circuit.
Can a PCB Stiffener Affect the Electrical Properties of a Board?
Some common problems caused by a lack of stiffeners include:Trace cracking – Excessive flexing in component mounting areas can cause traces to fracture. Component detachment – Unreinforced areas that are loaded with heavy components can become unstable when flexed.
When used in combination with the right flex PCB, stiffeners can protect each component from damage by adding support to the circuit. They can also prevent the flex from twisting around each component, thereby protecting soldered connections. They can also provide a hard surface to mount components, making them easier to install and maintain in the field.
In addition to these benefits, a stiffener can also help with heat dissipation and increase the lifespan of the board by reducing the amount of flexing it undergoes. If a flex circuit is designed with the proper stiffener, it can be a vital and durable component of any mobile device or industrial application. If you’re designing a flex circuit, talk to your manufacturer about the best options for stiffeners. They can advise you on the type, size, and placement of stiffeners to meet your unique project’s needs.
Customized stiffeners can be designed to address specific mechanical and thermal challenges faced by the PCB. This may include reinforcing critical areas prone to bending or warping, as well as providing enhanced heat dissipation for components with high power dissipation requirements. By tailoring the stiffness, thickness, and geometry of the stiffener, engineers can achieve the desired mechanical and thermal performance targets.
