PCB (printed circuit board) depaneling, also referred to as singulation, is the method of removing numerous smaller, individual PCB Depaneling from a larger multi-PCB panel produced during production. 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 other waste.
Demand Driven by Size
As technology will continue to evolve, the gadgets we use be a little more advanced and often decline in size. This reduced size requires smaller PCBs. Without any set standard for PCBs, every board is ideal for a certain item. Therefore, the process for depaneling separate boards from the multi-image board is unique. Production factors like stress, precision and cleanliness are paramount to keeping board defects to a minimum.
PCBs are generally manufactured in large panels containing multiple boards at any given time, but may also be produced as single units if need be. The depaneling of PCBs process could 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 procedure of singular PCBs being punched from the panel by using an exclusive fixture. The punching fixture has sharp blades on one part and supports on the other. Another die is necessary for every board and dies must frequently be replaced to keep up sharpness. Even though production rates are high, the custom-designed fixtures and blades demand a reoccurring cost.
Boards are scored over the cut line for both sides to lessen overall board thickness. PCBs are subsequently broken out from the panel. Each side in the panel are scored to your depth of around 30 percent of 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 can damage a number of the components or crack the solder joints, particularly 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 cut the other web. Accuracy is critical, because the V-score and cutter wheels should be carefully aligned. There is a slight level of stress on board which could 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 slice requirements through 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 can be subsequently broken or snapped to singulate the circuits. Routing will take up significant panel area as a result of wide kerf width of any physical bit.
Laser routing provides 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 can be lower than 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 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, due to lower power levels, the cutting speed is a lot vboqdt compared to the CO2 laser and also the cost/watt of UV lasers is higher than that of CO2
Generally speaking, companies 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 benefit from the greater speed in the CO2 laser.
Laser systems for depaneling play an essential role down the road in the PCB manufacturing industry. As need for Motorized PCB Depaneling still parallel technology trends, like wearables and Internet of Things (IoT) devices, the requirement for systems that increase production line speed and lower costs for manufacturer will even still rise.
In our Applications Development Lab, we work together with each client to ascertain the ideal laser and optics configuration to get a manufacturing process.
In this particular three-part series on PCB depaneling, upcoming posts will talk about the benefits and challenges of PCB depaneling, combined with the evolution of PCB depaneling with laser systems.