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Am I paying too much to have PCBs made?

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mrpackethead:
the dream of autorouting.. If you ask around the professuonal board desingers here ,there will be very few using auto-routing.. thats becaseu geenrally its rubbish

rea5245:

--- Quote from: mrpackethead on November 04, 2015, 01:53:23 am ---the dream of autorouting.. If you ask around the professuonal board desingers here ,there will be very few using auto-routing.. thats becaseu geenrally its rubbish

--- End quote ---

I've found that autorouting is always worth a shot. I've done a lot of projects where it did a fine job, and I've done two or three where I had to do manual routing. The ones that needed manual routing have had address buses or data buses or even a row of 14 segment LEDs. Essentially, a routing solution required lots of parallel traces; the autorouter couldn't see that and plan accordingly, but I could.

What the "professionals" do is irrelevant to what hobbyists like me do (and I notice you allowed that some professionals do use autorouting). My boards are smaller and simpler than a lot of professional boards. I suspect that even if I were a pro, I'd want my CAD program to offer the option of autorouting. And really ... are there any good CAD programs that don't have an autorouter?

So don't dis the autorouter. If it works for your project, use it without shame.

- Bob

mrpackethead:

--- Quote from: rea5245 on November 04, 2015, 02:11:14 am ---And really ... are there any good CAD programs that don't have an autorouter?

So don't dis the autorouter. If it works for your project, use it without shame.

- Bob

--- End quote ---

Theres several autorouters in CAD programs. Most of them produce garbage that needs significant work to clean up.   
50% of the work in PCB design is about placement and component choice. Where stuff goes reletive to each other makes a massive difference. Theres also a lot of arbitory choices you can make, ( simpel example, a 4 gate package.. any of the gates are good to use, but one will probalby provide a better layout.

theres often things that get complex enough that you have so many constraints.. ( differential pairs carrying high speed data, need controlled impedance, matched paths )..  that you just have to put those in..

Lastly, i know many folks would bork that the idea, but there is often signficant economy and massive time savings in going to a four layer PCB, from a 2 layer..     Your boards, often get much smaller. ( i've seen physical size reductions of 70% with my student engineers ). This is becuase you can run a gnd and power plane..    If you can reduce board size a lot, a small 4 layer board is going to be no more than a larger 2 layer.

rs20:

--- Quote from: mrpackethead on November 04, 2015, 03:23:35 am ---Theres several autorouters in CAD programs. Most of them produce garbage that needs significant work to clean up.   
50% of the work in PCB design is about placement and component choice. Where stuff goes reletive to each other makes a massive difference. Theres also a lot of arbitory choices you can make, ( simpel example, a 4 gate package.. any of the gates are good to use, but one will probalby provide a better layout.

theres often things that get complex enough that you have so many constraints.. ( differential pairs carrying high speed data, need controlled impedance, matched paths )..  that you just have to put those in..

Lastly, i know many folks would bork that the idea, but there is often signficant economy and massive time savings in going to a four layer PCB, from a 2 layer..     Your boards, often get much smaller. ( i've seen physical size reductions of 70% with my student engineers ). This is becuase you can run a gnd and power plane..    If you can reduce board size a lot, a small 4 layer board is going to be no more than a larger 2 layer.

--- End quote ---

Again with the all-vs-nothing, black-vs-white, you-vs-me internet mentality. Have you considered this case: manually placing components (e.g. a bunch of shift registers and 7 segment displays) and critical power and data lines manually; and then using the autorouter to place the 200 tracks from shift register to 7 seg displays? If you already have 4 layers for some other reason, it does an absolutely perfect job and saves a huge amount of time.

Saying autorouters are completely useless and should be avoided at all costs is equally as silly as someone who exclusively uses autorouting. There are shades of grey here...

mrpackethead:

Saying autorouters are completely useless and should be avoided at all costs is equally as silly as someone who exclusively uses autorouting. There are shades of grey here...
[/quote]

My grey might be more dark that yours.. but i did use words like"most" and "often".  don't think i was compeltley black or white, by saying "all" or "none".    Sigh, guess with internet mentality, you did'nt read that.

Sigh.

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