PCB (printed circuit board) depaneling, also referred to as singulation, is the procedure of removing numerous smaller, individual PCBs from a larger multi-PCB panel produced during manufacturing. The depaneling process was created in order to 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 frequently reduction in size. This reduced size requires smaller PCBs. Without any set standard for PCBs, every board is made for a certain item. Therefore, the process for depaneling separate boards coming from a multi-image board is unique. Production factors like stress, precision and cleanliness are paramount to keeping board defects to a minimum.
PCBs are usually produced in large panels containing multiple boards at a time, but may also be produced as single units if necessary. The depaneling of PCBs process can be fully automatic, manual, or semi-automatic. There are numerous 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 out of the panel through the use of a special fixture. The punching fixture has sharp blades on one part and supports on the other. A different die is required for every board and dies must frequently be replaced to keep sharpness. Even though production rates are high, the custom-designed fixtures and blades demand a reoccurring cost.
Boards are scored along the cut line on both sides to reduce overall board thickness. PCBs are subsequently broken out from the panel. Both sides of the panel are scored to your depth of around 30 percent from the board’s thickness. Once boards have already been populated, they can be manually broken from the panel. There is a strain put on the boards that may damage a few of the components or crack the solder joints, in particular those near to the fringe of the board.
Wheel Cutting/ Pizza Cutter:
The “pizza cutter” method is a manual option to breaking the net after V-scoring to cut the remaining web. Accuracy is critical, because the V-score and cutter wheels should be carefully aligned. There exists a slight amount of stress on board which could affect some components.
Laser depaneling can be executed on boards requiring high tolerances. Depaneling occurs without physical contact, with no mechanical stress, and is adaptable to slice requirements through 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 are subsequently broken or snapped to singulate the circuits. Routing may take up hbrerp panel area because of wide kerf width of a physical bit.
Laser routing supplies a complete software-controlled process without reliance upon 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 executed using either:
High-power CO2 laser (~10µm wavelength)
The CO2 laser can thermally cut through FR4, glass fibers as well as other rigid and flex circuit substrates at comparatively high speed however with noticeable heat effect on the side of the cut for most substrates.
Solid-state UV laser (355nm wavelength).
The UV laser, using a considerably smaller focused spot size, ablates the panel material with significantly less heat along with a narrower kerf width. However, because of lower power levels, the cutting speed is significantly slower compared to CO2 laser and also the cost/watt of UV lasers is higher than that of CO2
Generally speaking, businesses that are responsive to char and fine debris over the cut line will employ the UV laser while users who clean the circuits after singulation may benefit from the greater speed of the CO2 laser.
Laser systems for depaneling play an important role later on of the PCB manufacturing industry. As interest in Inline PCB Laser Depaneling continue to parallel technology trends, like wearables and Internet of Things (IoT) devices, the necessity for systems that increase production line speed and reduce costs for manufacturer may also continue to rise.
Within our Applications Development Lab, we work with each client to ascertain the ideal laser and optics configuration for a manufacturing process.
Within this three-part series on PCB depaneling, upcoming posts will talk about the huge benefits and challenges of PCB depaneling, combined with the evolution of PCB depaneling with laser systems.