Best way to make home made PCBs?

[Oliver]

trekiej wrote:
I do not know if .030 thick boards can be found with dual copper already applied...
edit: Nov.30,2007
...Does anyone sell .030 inch double sided boards on the web?...

Why are you concerned about the board thickness? Are you doing particularly high frequency circuits? Do your boards need to be particularly robust, or conform to a particular form factor? The thickness is rarely an issue worth considering.

I had a brief look at the Think & Tinker site. I found it a bit too dissorganised to scan through it quickly, but I think their processes are rather elaborate.

What kind of circuits are you designing? Usually, quite simple processes are sufficient for beginner to intermediate home made PCB's.

If you are doing more complex designs, or releasing a significant number of boards, then home made usually doesn't work out too well.

edit- spelling  :-(

[HenryCase]

Check out this video:
http://www.youtube.com/watch?v=sDddSJd617g
The relevant sections start around 31:15 and 43:20.

[Oliver]

HenryCase wrote:
Check out this video...

I think the direct toner transfer method is a lot more useful.
1)  Design the circuit in a schematic capture program (I use protel)
2)  Download, import, or draw your own PCB layout library parts (basically just footprints, and pin assignations)
3)  Take a netlist from the schematic into a PCB layout program
3)  Layout the PCB
4)  Print the copper signal layers with a laser printer, onto coated colour pinting paper, or tranparency (this can also be done with a photocopy of a layout, onto the appropriate coated paper/transparency)
5)  Clean the PCB with scotchbright or similar plastic scourer
6)  Iron transfer the toner from the printed layout onto the copper cladding
7)  Dissolve the paper away from the copper, leaving the toner
 Touch up the toner with a sharpie or equivalent pen
9)  Allow to dry
10) Etch (I use heated sodium persulphate)
11) Drill, etc

One can make quite sophisticated layouts in this fashion, with a good success rate. A few minor errors per board can be fixed, but I have rarely had to do this. Of course, the key to success is in a good circuit design, and not too ambitious a layout for the first time.

[trekiej]

@ Oliver
I guess it depends on how thick you want your board to be.
Have you made 4 layer boards before?
I wonder how one would judge the density of the circuits before needing multilayers.
Good day.

[Oliver]

@trekiej
I've never tried home made 4 layer boards. I think that would be too much trouble. 2 layers is difficult enough for DIY. How would you fabricate and test blind and buried vias? If doing something that intricate, I would suggest getting a prototype frame manufactured.

Judging the number of layers one will need for a particular circuit is a matter of experience.

If you have a simple signal flow, from one input port to one output port, single layer is likely to be fine. If one has a few ports, each with input and output, the topology is likely to be multi-point to multi-point, and extra layers would be very handy. Many layouts can be done in a neat and simple manner, with suffient forethought. This forethought should start when doing the brainstorming for the schematic.

I have not yet needed to make any four layer boards for my job. They are about double the price of a 2 layer board. The company I work for, mostly just does our main products on 4 layers. All our peripherals are done on 2 layers.

It's often cheaper to make a board a bit bigger, more generously spaced, or if doing home made, one can use jumper wires for the extra layering.

If doing high frequency designs, one may need internal gound/power planes, for which the additional layers are most useful. There are many other reasons as well, but for most people doing DIY PCB's, single layer w/jumpers or 0 Ohm links would be quite sufficient.

Just as a matter of interest, what kind of circuits are you designing?

[trekiej]

@ Tonyyeb
Sorry to have taken over the thread.
@Oliver
I wish I could get two high density FPGA chips on a mATX or standard ATX board for building a new computer.
As far as 4 layer board are concerned,  the blind vias, I believe, are electro-plated and have contact pads between boards that dig into each other between each layer( thinktink).  
If a board was layered A,B on the first board and  C,D on the next board, I could connect A to B and C to D then A to D. Edit:  I bet I would have to make sure the two boards were good before I joined them.
What do you think?  
I do not know much about signal integrity and noise and other related physics to really be of help.
Good day.