Production Costs of a Flex PCB
A flex PCB is a key component in many electronic devices that require flexibility and durability. The emergence of new-generation devices has fueled demand for flex circuits. However, the cost of a flex circuit board can be prohibitive for some manufacturers. Fortunately, there are ways to reduce the cost of a flex circuit board.
The primary cost drivers of a flex pcb manufacturer are the board materials, layer count, efficient panel utilization, and stiffeners. These factors are not much different from rigid boards. However, a few other additional factors can increase the cost of a flex circuit board.
PCB materials account for the largest percentage of the overall cost of a flex PCB. The choice of a laminate material is critical. It should meet the requirements of the application without compromising the circuit board’s functionality. Typical options include FR-4 and polyimide.
How to Reduce Production Costs of a Flex PCB
Other factors that impact a flex PCB’s price include the number of layers, copper thickness and finish, line width/spacing, and hole size. In addition, the use of special materials like high-reliability polyimide can also raise the price of a flex circuit.
In terms of layers, the higher the number of layers, the more expensive a flex PCB will be. This is due to the increased manufacturing complexity and materials required to produce a circuit board with a high-layer count. Moreover, higher-layer counts require more time to laminate and cure.
The design of a flex circuit board also impacts its production costs. Some techniques common to rigid boards are harder to achieve in a rigid flex design, which can lead to lower overall manufacturi ng yields and thus raise the cost of the finished product. These techniques include via in pads requiring filled vias, dual surface finishes such as ENIG and electroplated nickel gold or hot air leveled solder, and buried, blind, and laser vias.
Another way to lower a flex PCB’s cost is to minimize the number of holes. This can be done by using blind and buried holes, sequential layer lamination, or by increasing the number of solder mask openings. The resulting holes are smaller, reducing the overall thickness of the PCB.
In addition to reducing the number of holes, a fab house can also lower a flex circuit’s cost by increasing the area of plated through holes. Using larger through-holes reduces the number of drills needed to create them and cuts down on the amount of waste metal generated during the process.
A fab house can also save money by using thermal adhesives instead of pressure-sensitive adhesives to attach coverlays to a flex circuit board. Thermal adhesives are cheaper than PSAs and also allow the fab house to improve manufacturing yields.
Ultimately, the cost of a flex PCB can be reduced through careful design optimization. Limiting the number of layers reduces the amount of prepreg plies that are required to bond the layers together. Additionally, limiting the number of layers can optimize the manufacturer’s ability to improve manufacturing yields and reduce the cost of the final product.
