Flex PCB Manufacturers Support Customers
There are a lot of things that go into making a flex PCB. From the conductive tracks on a non-conductive polyimide base, to stiffeners for specific areas of the circuit that need additional mechanical support. From the electrical perspective, a flex or rigid-flex circuit must be able to handle vibration and dissipate heat effectively. They must also be able to bend, fold and configure into different shapes without losing their structural give. They must be able to perform under harsh environmental conditions too – shock, chemicals and temperature extremes for instance. To address these issues, the materials of a flex or rigid-flex circuit should be modeled early in the design process to ensure that the circuit will perform well and meet the desired performance criteria for your final product.
During the design phase, it is important to consider all of the options that may affect your flex PCB’s cost. The first consideration is the substrate material – single- or double-sided, with and without silver shielding. Once that has been decided, the next decision is whether a coverlay or solder mask should be applied to the top side of the circuit and if so in what color(s). Finally, there are a number of surface finish options – some are better than others for handling abrasion and vibration.
The selection of the copper foil used for a flex circuit is also an important factor to understand. Unannealed copper is notorious for work-hardening and fatigue cracking – not good for a flex pcb manufacturer circuit that will be moving and creasing constantly. Rolled annealed copper, on the other hand, will stretch much further before fatigue cracking occurs. It is also springier in the z-direction which will help reduce stress and strain on your circuit during bending.
Flex PCB Manufacturers Support Customers With Design Optimization
Once the copper foil has been placed on the substrate, it must be plated and etched. The choice of plating is important as well, with pad-only-plating (button plating) offering a significant cost savings over traditional panel plating that uses the entire copper layer on the surface of the board. In addition, it will be necessary to determine whether hole-fill is required and what type of plating is needed (gold or nickel).
As a general rule, optimizing your flex circuit design for panel layout utilization will lower overall manufacturing costs. This includes the fabrication of a panel, the running and maintenance costs of the equipment and materials needed to make individual boards.
Another cost factor that can be affected is the choice of what’s called a stiffener, which is a piece of rigid material like FR4 added to selected areas of the flex circuit. Adding stiffeners to your flex or rigid-flex circuit will increase the thickness of the board, which can impact signal transmission between areas of the circuit. You should also take into account that a stiffener will add an extra step to the manufacturing process of your flex circuit. To help you understand the impact of these decisions, we invite you to watch a recent webinar from Epec Engineered Technologies.