PCB (printed circuit board) depaneling, also known as singulation, is the process of removing many smaller, individual PCB Depaneling from a larger multi-PCB panel produced during manufacturing. The depaneling process was created so that you can increase throughput of PCB manufacturing lines as circuit board sizes reduced. At CMS Laser, our depaneling process has the benefit of speed, pin-point accuracy, no tooling cost or wear, no part induced stress, with no cutting oils or some other waste.
Demand Driven by Size
As technology will continue to evolve, the gadgets we use become a little more advanced and quite often reduction in size. This reduced size requires smaller PCBs. Without any set standard for PCBs, every board is designed for a certain item. Therefore, the procedure for depaneling separate boards from a multi-image board is unique. Production factors including stress, precision and cleanliness are paramount to keeping board defects as low as possible.
PCBs are generally manufactured in large panels containing multiple boards at the same time, but can also be produced as single units if necessary. The depaneling of PCBs process can be fully automatic, manual, or semi-automatic. There are several methods used, including laser PCB depaneling, within the electronics industry. Let’s examine whatever they are:
The punching method is the procedure of singular PCBs being punched out from the panel with the use of a unique fixture. The punching fixture has sharp blades using one part and supports on the other. A different die is required for each board and dies must frequently get replaced to maintain sharpness. Even though production rate is high, the custom-designed fixtures and blades demand a reoccurring cost.
Boards are scored across the cut line on sides to reduce overall board thickness. PCBs are subsequently broken out of the panel. Both sides from the panel are scored to some depth of about 30 percent of the board’s thickness. Once boards have been populated, they can be manually broken out from the panel. There is a strain put on the boards that may damage a number of the components or crack the solder joints, especially those close to the fringe of the board.
Wheel Cutting/ Pizza Cutter:
The “pizza cutter” method is a manual option to breaking the internet after V-scoring to reduce the other web. Accuracy is essential, since the V-score and cutter wheels has to be carefully aligned. There exists a slight degree of stress aboard which may affect some components.
Laser depaneling can be performed on boards requiring high tolerances. Depaneling occurs without physical contact, without any mechanical stress, and is also adaptable to cut requirements via a computer controlled process. Laser depaneling would work for installation in surface mount technology (SMT) lines or with board unloaders/loaders for standalone operation.
Most Laser PCB Cutting Machine 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 will take up significant panel area due to wide kerf width of the 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 could 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 though with noticeable heat effect on the edge of the cut for many substrates.
Solid-state UV laser (355nm wavelength).
The UV laser, having a considerably smaller focused spot size, ablates the panel material with considerably less heat as well as a narrower kerf width. However, because of lower power levels, the cutting speed is significantly vboqdt compared to the CO2 laser and the cost/watt of UV lasers is higher compared to CO2
In general, companies that are sensitive 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 larger speed in the CO2 laser.
Laser systems for depaneling play an important role down the road in the PCB manufacturing industry. As need for Manual PCB Depaneling continue to parallel technology trends, like wearables and Internet of Things (IoT) devices, the need for systems that increase production line speed and lower costs for manufacturer will even still rise.
Inside our Applications Development Lab, we work with each client to determine the ideal laser and optics configuration to get a manufacturing process.
In this three-part series on PCB depaneling, upcoming posts will discuss the advantages and challenges of PCB depaneling, along with the evolution of PCB depaneling with laser systems.