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Topic: Practical limits? (Read 928 times) previous topic - next topic

Practical limits?

I'm hoping to start a discussion to find out what others have used in terms of design limits and what success they have had with the resulting boards.

For example, the minimum track / gap is quoted as 6 mil. I tend to be conservative here and use 10 mil unless I have a really tight layout where I have gone down to 8 mil. Does anyone regularly use 6 mil and if so, what sort of success rate have you had? FWIW, I've had no issues at all with 8 mil.

However, for vias I have had some issues. They quote 12 mil as the smallest finished size and 2 mil as the drill position tolerance. I've used vias which I defined as 28 outer, 14 mil hole where some boards are scrap due to issues with these vias. I even had one where I used 32/16 and a few vias were faulty. These were 0.8mm thick boards. I would say that only a small percentage of boards were faulty this way

Conversely, I've had 20/12 vias which worked fine so maybe it's a board house issue.

Anyone else care to share their experiences? It'd be good to get a feel for what the service can actually deliver reliably so we can either push closer to the limits or back off a bit to ensure we get working PCBs.