Flex Circuit Prototypes
A flex circuit is an electronic board that can be bent, folded, formed and twisted. The ability to bend in three dimensions provides more flexibility and easier access to components for assembly and maintenance. It is often used in tight spaces, especially in handheld devices such as portable ultrasound systems and medical equipment for life support.
The design process for a flex circuit begins by determining how much bending is required. If the circuit will only be bent once and then left in a fixed position, such as in an ultrasound device, it is possible to use a more rigid structure that can be built on a standard base material. However, if the flex circuit will be continuously bending or crisscrossing in a dynamic application such as a laptop computer hinge, a higher-quality flex structure is necessary.
flexible circuit can be made using a variety of base materials including epoxy, acrylic and PSAs (pressure sensitive adhesives). They can also be built on an adhesiveless substrate. Conductors are typically copper, although other metals may be used. Insulators separate the conductors, keeping them from touching and allowing current to flow freely. Insulators are usually covered with a layer of polyimide or solder mask.
Testing Methods Used to Ensure the Reliability of Flex Circuit Prototypes
When a flex circuit is designed, it’s important to consider the design rules for flexible printed circuit boards. For example, a flex PCB needs to have a minimum copper-to-copper distance of 8 mils. Also, it is important to use a high-quality solder mask and avoid the temptation to add extra vias because these can cause signal degradation in harsh environments.
A quality flex circuit manufacturer will adhere to IPC standards for design and fabrication. This includes guidelines for drilling, layer stacking and soldering. They will also be able to provide a range of testing services to ensure the reliability of your flex circuit prototypes, such as power-on and power-off electrical tests.
When selecting a flex circuit manufacturer, look for one that offers turnkey PCB design and manufacturing. This eliminates multivendor miscommunication and enables you to work with a single company to develop a reliable prototype that will meet your needs. You should also choose a manufacturer that has advanced assembly and testing equipment to help ensure the highest quality product.
Another consideration when choosing a flex circuit producer is their level of certifications and accreditations. You should look for a manufacturer that has IPC, ISO and UL certifications and approvals to ensure the production of a quality prototype.
Once the flex PCB is finished, it must be tested to ensure that the final product meets its specifications and requirements. Testing methods include electrical, in-circuit and mechanical. Electrical tests involve probing and measuring different parameters such as resistance, capacitance and impedance in order to identify any shorts, opens or signals that have degraded over time. Mechanical tests include insertion tests, wedge lock test and solvent extract tests. This allows the engineer to determine if the final flexible circuit is fit for its intended application.