PCB (printed circuit board) depaneling, also called singulation, is the process of removing numerous smaller, individual PCBs from a larger multi-PCB panel produced during manufacturing. The depaneling process was created so that you can increase throughput of PCB Router as circuit board sizes reduced. At CMS Laser, our depaneling process has the advantage of speed, pin-point accuracy, no tooling cost or wear, no part induced stress, and no cutting oils or other waste.
Demand Driven by Size
As technology continues to evolve, the gadgets we use become a little more advanced and often decrease in size. This reduced size requires smaller PCBs. With no set standard for PCBs, every board is ideal for a certain item. Therefore, the process for depaneling separate boards coming from a multi-image board is exclusive. Production factors including stress, precision and cleanliness are paramount to keeping board defects as low as possible.
PCBs are typically manufactured in large panels containing multiple boards at the same time, but may also be produced as single units if need be. The depaneling of PCBs process may be fully automatic, manual, or semi-automatic. There are several methods used, including laser PCB depaneling, in the electronics industry. Let’s examine what they are:
The punching method is the process of singular PCB Router being punched from the panel by using a unique fixture. The punching fixture has sharp blades using one part and supports on the other. Another die is required for each and every board and dies must frequently get replaced to keep sharpness. Even though production rate is high, the custom-designed fixtures and blades need a reoccurring cost.
Boards are scored along the cut line on sides to reduce overall board thickness. PCBs are subsequently broken out from the panel. Either side of the panel are scored to some depth of around 30 percent of the board’s thickness. Once boards happen to be populated, they could be manually broken out of the panel. There is a strain put on the boards that can damage a number of the components or crack the solder joints, particularly those near the edge of the board.
Wheel Cutting/ Pizza Cutter:
The “pizza cutter” technique is a manual substitute for breaking the internet after V-scoring to cut the remaining web. Accuracy is critical, as the V-score and cutter wheels has to be carefully aligned. There is a slight level of stress aboard that could affect some components.
Laser depaneling can be performed on boards requiring high tolerances. Depaneling occurs without physical contact, without mechanical stress, and is adaptable to reduce requirements via a computer controlled process. Laser depaneling is suitable for installation in surface mount technology (SMT) lines or with board unloaders/loaders for standalone operation.
Most PCBs are routed leaving the patient circuits connected to the panel frame by narrow tabs which can be subsequently broken or snapped to singulate the circuits. Routing will take up hbrerp panel area due to wide kerf width of any physical bit.
Laser routing supplies a complete software-controlled process without reliance on any mechanical dies or blades. Laser routing can cut any shape path including curves and sharp corners. The cut kerf width may be under 20 microns, providing exceptional accuracy.
Laser routing can be carried out using either:
High-power CO2 laser (~10µm wavelength)
The CO2 laser can thermally cut through FR4, glass fibers along with other rigid and flex circuit substrates at comparatively high-speed however with noticeable heat effect on the edge of the cut for the majority of substrates.
Solid-state UV laser (355nm wavelength).
The UV laser, having a considerably smaller focused spot size, ablates the panel material with significantly less heat along with a narrower kerf width. However, as a result of lower power levels, the cutting speed is much slower compared to the CO2 laser as well as the cost/watt of UV lasers is higher compared to CO2
In general, businesses that are responsive to char and fine debris along the cut line will employ the UV laser while users who clean the circuits after singulation can be helped by the higher speed from the CO2 laser.
Laser systems for depaneling play an important role later on from the PCB manufacturing industry. As need for Inline PCB Laser Depaneling still parallel technology trends, such as wearables and Internet of Things (IoT) devices, the need for systems that increase production line speed and reduce costs for manufacturer will also carry on and rise.
Inside our Applications Development Lab, we assist each client to ascertain the ideal laser and optics configuration for any manufacturing process.
In this particular three-part series on PCB depaneling, upcoming posts will talk about the advantages and challenges of PCB depaneling, along with the evolution of PCB depaneling with laser systems.