Circuit-board, design software.

[ynneb]

I have a circuit that I want to make a board for. I want to be able to route out the board and therefore make a cutting code for it.

Does any one know of a freeware application that can do this for me. I don't want to buy some software because I don't think I will use it very much at all.

I know I could use the traditional method with a pen on a copper board but I wishes to make a few of the same board so it would be better if I could route it. Whats more it would look better and be more fun.

Thanks for the help.

[pminmo]

Eagle has a free version for hobbiests. www.cadsoftusa.com Also has a built in autorouter.
1. Enter the schematic
2. Locate the parts on the board
3. Start the autorouter and watch.

Phil

[arvidb]

I think Benny meant he wants to use the router to produce the traces on the actual PCB (instead of etching etc), not that the freeware program must have an autorouter

Arvid

[fyffe555]

Eagle doe sthat. Has User programs to produce g-code to mill the traces. Works pretty well until the traces start getting closely packed.

[ynneb]

I downloaded the software. Thanks for the link.
It looks like it has a severe learning curve. Bugger

I look forward to the day when you will ba able to talk to a computer and tell it what you want and it will do it for you.

5 years off?

[pminmo]

It definitely has a learning curve, but it comes quickly. Benny how intense is the circuit? Maybe I can help.

Phil

[ynneb]

Here is the circuit. I found it on the net.
I was hoping to put 3 of these circuits onto the one board and a common connection to a printer port cable connector.

When I have the cutting code I was hoping to post it back into the open source forum so that people could either cut the boards and distribute them, or others could just use the photo method to make thier own board.

I am desperate to get a open source board out there.

[pminmo]

Benny,
How big of a hurry are you in? The one issue with eagle for the hobbyist is the size of the pcb is limited, getting three of those on a board maybe to much for eagle. I however will give it a go.

Phil

[jstuedle]

Phil,
Please post your results. Enquiring minds want to know.

[vladdy]

just curious as to why you want to 're-invent' this PCB.. the kists themselves are cheap enough, and work ok for light hobby use..

[fyffe555]

Had Eagle open anyways so what the heck....

I'm sure (hope!) that Phil will put up a decent version but attached here is a Zip with an Eagle 4.11r2 Freeware layout of Benny's board, one driver only, for people to play with. Hope it might be of use.

Included in the zip is an Eagle schematic (sch), double sided board routing (brd) and the gcode files produced by an eagle ULP to drill, isolation mill top and bottom traces and pads and the board outline.

It's worth noting the following. This is not a finished layout! took about thirty minuites and so needs some work!. Most of the time was spent searching the xvt!@#$ eagle libraries for similar component pad layouts. Surprisingly the 40xx's are not the problem, its the size of caps resistors and the connnectors that takes time. SO, to fix this you need to know the physical package of the components you're going to use and put those in the schematic and re (auto) route the board. By way of example you'll see I couldn't find the irfz44 so used a similar packaged device.

The cnc milling is the most interesting piece here. The G-code needs very little work to run it through Turbo CNC and cnc simulator.

The G Code is an outline of the trace only and assumes a 1-2thou cut (!) and is centred on the trace outline. Some work will be necessary in eagle and a cut simulator to set the necessary trace and pad sizes or it doesn't work very well. Consider an 8 mil trace as to small, if you're cutting its outline, the cutter must be les than the widthe of the trace..

When trying to pack stuff together. It gets worse. If you look the board the isolation milling needs to cut a 1-2 thou channel in the Cu and maintain a positional accuracy of around 2-3thou. I've tried this with a carbide 60 degree bit and its not very effective and unless the bit is very sharp, the feed rate just right the copper burs up. My machine is small and stiff and cut more accurately than expected abd still had difficulty putting a trace between pads.

Hopefully anyone with better experience can tell us here.

Now I use Toner transfer method to etch the boards, and the Drill and outline gcodes to drill the board. Have to watch the scaling from the printer and adjust eagle to match what your cnc machine drills for inter pad dimensions. Had great results with The HF carbide bits , 50 for $14 or something for drilling and milling to size. Use double sided tape to hold it down and drill before etching. You can create an eagle drill file with your drill sizes and eagle sets up a Gcode with sections and tool change pauses for each size.

hope that starts a few ideas.

Andrew

[pminmo]

Andrew,
I learn something new on eagle all the time. First time I had seen pins displayed on a schematic! Seing your layout makes me thing we can fit 3 ona a board, but not sure with a db25 though.

Phil