A lot of small quantity PCBs come individually routed these days, but when they get too small or come in larger quantities, panels can be very nice to have. When you have your PCBs panelized, what's your preferred method? And why?
PCB assemblers get questions about this often: "What's the best way to panelize my boards?" When in doubt, always follow the specific guidelines from the manufacturer assembling your boards. Just remember most manufactures won’t specify whether you should use V-score or tab routed. That's a decision best left to you.
What if you don't know? First, easily eliminate a few options. For example, if you have curves in your board outline, you can't V-score. V-scoring only works in straight lines. With curves or odd shapes, you have to use tab-routed.
If your outline is a pure rectangle, V-scoring tends to require less board-edge so you can get a bit more out of your PCB real estate. But it's more difficult to deal with on very thin boards, and V-scoring leaves a rougher edge after snapping the boards apart.
Two of the key disadvantages of tab-routing are the greater waste area and the nubs that stick out after separating the boards. You can leave the nubs, sand them down or use a clean-up router.
Here’s a quick guide to help you decide:
- If it truly doesn't matter, use whichever method is less expensive or that you think looks prettier.
- If you have curves or other odd shapes, you'll probably need to go with tab-routed.
- If your boards are rectangles and you can deal with the less-smooth board edge, go for the V-score.
Duane Benson is the Chief Technology Champion at Screaming Circuits.