Hello.
Thank you for listening to my doubts.
I've two questions mainly related to routing in the board designs.
1. I usually design boards which have a lot of connections. Being a lazy person, and with the awesome autorouting capabilities of EAGLE, I prefer to autoroute everything. Now I've many connections which should have different widths, like the power lines should be thicker [20 to 25mils] while normal I/O wires can go down to 16 or even 12mils. What I do in that case is create different netclasses for different types of connections [set different widths, via diameters, and clearance values], and then autoroute it. It works absolutely perfectly.
Now in my current board design, I've a situation where I want the very same connection [net] to be 20mils at certain places and 12 mils at certain places. Using netclasses I can either set it to 20 or 12mils at a given time, not both. So I can only autoroute that connection at 20mils first, then remove [ripup] the part that should be 12mils and autoroute the same connection again [with 12mils netclass] to get the autoroute to route at 12mils.
So is there any other way I can solve this situation by routing the very same connection [net] at two or more different widths at different physical points on the board at the same time? That way I'll only have to autoroute the whole board just once. Any help will be appreciated. By the way, the autorouting capabilities of EAGLE are simply amazing. Thank you EAGLE team for that functionality.
2. Thank you again for taking the time to read my doubts. My second doubt regarding board designs is about the polygon filling [copper pouring] part. I usually design double-sided boards with both sides polygon fillings of Ground planes, and occasionally 5V or 3.3V fillings.It might be a stupid question but should I fill the layer before starting my routing, or do it after I've routed the board 100%?
Having already mentioned above that I usually use the autoroute capabilities of EAGLE, if I autoroute my boards after polygon filling, I get a message that "polygons may have fallen apart".
When I fill the board before routing, I need to make proper vias at different points so that both layer fillings are shorted at all points. And it also makes the routing part tougher for me or the autorouter [maybe I'm wrong].
On the other hand, the opposite is much easier, i.e. routing the board first and then doing the pouring.
I personally feel that the copper pouring should be done before the routing, because doing it after everything has been routed doesn't improve the connections according to me. Again, any advices on this topic will be greatly appreciated.
Thanks a lot for even taking the time to go over my doubts.
Any inputs will be greatly appreciated.
And thank you team EAGLE for this lovely piece of software. Without you all I would have given up PCB designing. You all make it easy.
Rahul Sharma.