A Few Rules about PCB Panelization

A Few Refined Rules about PCB Panelization

PCB panelization is to panel multiple PCBs together in a certain arrangement to facilitate SMT and improve welding efficiency.

1. Why panelization is needed?

• In order to meet the needs of production. Some PCB boards are too small to meet the requirements of making fixtures, so they need to be put together for production.

• Improve the welding efficiency of SMT assembly. It only needs one SMT to complete the soldering of multiple PCBs.

• Improve cost utilization. Some PCB boards are special-shaped, and panelization makes more efficient use of the PCB board area, reduces waste, and improves cost utilization.

2. How many ways of panelization design?

(1). V-CUT

V-CUT is to cut a slot at the junction of two boards, that is, put two boards together and leave a little gap between them(generally 0.4mm). However, the connection of the boards in this place is relatively thin and easy to break, so the edges of the two boards need to be merged together while panelization.
V-CUT is a straight line in general and there are no complicated routings such as curved arcs. Try to be in a straight line when joining boards.

(2). Stamp hole

For irregular PCB boards, such as round ones, V-CUT doesn't work. At this time, Stamp holes are needed to connect the boards, therefore, Stamp holes are generally used in special-shaped boards. Connect the edges of the two boards with a small bar, whose connection place with the two boards has few small holes and thus is easy to break. The edge of the broken board looks like the edge of the stamp, so this kind of panelization way is called stamp hole.

(3). Break-away Tab

Break-away Tab are often used in boards with half plated hole technology. They use very narrow tabs for connection, which are similar to stamp holes. The difference is that the connecting part of the Break-away Tab is a bit narrower and there are no vias on both sides.
There is a shortcoming of the Break-away Tab's paneling method: There is an apparent bump after the board is break off. The stamp holes also have bumps, which are not so obvious because they are separated by vias.

Some people may think that it is good to use the stamp hole directly, but why use Break-away Tab? This is because when a half plated hole module is made on all sides, neither the stamp hole nor the V-CUT can be used. They can only be connected at the four corners of the module through Break-away Tab.

3. What's the principle of panelization?

In order to facilitate production, try to keep the board being the shape of square after paneling. In short, don't let the difference between the length and width ratios be too big.

4. Requirements of spacing

• For the PCB whose outermost component is less than 3mm from the board edge, a process edge must be added, and the longer side is usually used as the process edge;

• A space > 0.5mm should be reserved between the components and the V-CUT to ensure the normal operation of the tools.