Al Williams' book on PCBs

Are you *sure* it was 'SoftCAD' and not 'CADSoft' ?

They produce the 'EAGLE' PCB CAD software which is free for 100mm x 80mm PCB size, 2 layers and one page of schematics.

I've run EAGLE on Windows (ME; XP SP1 and SP2) and Linux (Red Hat 9 and Fedora Core 2) and it runs very stable; I can recommend it.

Chris

Hi,

I can attest to the fact that CadSoft Eagle is very stable, and all in all a great program. You'll really like it, they're very dedicated people. If you're gonna use it I can advise you to also immediately join their forum.

As to the making of PCB's, I just print (using an old inkjet printer) on a transparent overhead projector sheet.

Since my old deskjet isn't very consistent in the ink disposal, and the ink tends to be a bit too transparent in places, I always print twice and tape the two prints together. Try to be very precice when doing this, a good magnifier (I use a lens from a junked photo enlarger) is indispensable -- you'll also need it to inspect the final product, your pcb. If there still are places that are too light, I often even manually touch up one of the prints with a fine ink drawing pen (0.13mm), using said magnifier and a backlight.

To transfer the print to the photo-pcb board, I use an old UV face tanner (4x16Watt I think). Some ballpark figures: UV at ca. 10cm above print/pcb, 120s exposure, developing (in FeCl) at room temp. some 15-20s; etching ... depends -- I never bring the etchant to temperature (which should be about 50 Celsius I think), so etch at room temperature. I just leave it in for about 45 minutes, then go back to it and with a tweezer stir it which will result in a clean pcb in about 10-15min. The deveoper and etchant you can in any good electronics store, at least over here in Holland. For the etcher I think you could also use plain sink deblocker (caustic soda) in some dillution, but I've never tried it.

I always drill my 0.8mm holes by hand, using a common home drill (actually it's quite a heavy type too). Microtools are for whimps ;-)

I've designed (with Eagle, on Linux btw.), printed, echted and soldered complete small pcb's in one day ;-) One caveat: this can become addictive!

Good luck.

bjd bjdouma AT xs4all DOT nl

I've downloaded it.

I know that is the usual way to do it. The point of my question is whether anyone has tried what Al Williams said, i.e. to transfer directly from paper or transparency to the copper clad board by ironing the paper or transparency on the copper clad board. That apparently causes the toner, which serves as a resist, to melt enough to attach to the copper clad board instead of to the paper or transparency. For this, he insists on using a laser printer.

: I was looking through Al Williams' TAB book on making your own printed : circuit boards this evening in a bookstore. One of its features is : a CD containing some free CAD software from SoftCad, which allegedly : runs under Windows and Linux. I don't know whether it would run on : my particular machine which has RedHat 7.1. I went to

Try

I think I've seen this method discussed on one of the Dutch electronics forums. I have no personal experience with it, though I'd say it might work. If I were you I'd just try it, I mean I'd experiment with fake laser-prints and some materials that might resemble the pcb sensitive layer, just to see if the transfer occurs at all, and if so, at what temperature. Then just try it on a small real pcb. That's why I would do.

Another method is to print the pcb layout directly onto the pcb using a flatbed plotter. I obtained two old Mural 8000 plotters (A0!, slight overkill for the pcb's I make...) recently to exactly that end, but haven't given it a try yet

-- no pens to be found in this vicinity (meaning I'll have to construct my own from a fine ink drawing pen, something which I haven't come around to yet).

How do you like Eagle?

bjd

The software with the book is the "freeware" version of CadSoft's Eagle CAD. It is fully free for personal use and works with boards up to a half Eurocard in size and two sides. The software has a great library and a pretty strong autorouter along with schematic capture. If you want more than 2 sides or bigger boards, you do have to upgrade, but the software is well worth the expense and many people get along fine with the freeware version.

The PCB toner method works very well once you find the right combination of paper, laser printer, and iron that works for you. One thing to note is that you don't iron the pattern onto photoresist. You actually put it on the bare copper and the toner IS the resist.

As someone else said earlier, get a blank copper board and an iron and experiment. When it doesn't work, you can always strip the board back down with acetone and try again.

The book covers this method in detail along with photo methods. It also covers how to use Eagle (including things like building custom components and sending CAM files out for production).

Regards,

Al Williams

I've walked around in wrinkled clothes my entire adult life because I don't own an iron. I have a Canon BC02 Bubble Jet printer and no laser printer. So it will involve some commitment of resources to simply try it. Before doing that, I just wanted to know whether anyone else had any experiences to report, other than the author. (Thanks to Al Williams for adding his helpful comments to this discussion. I don't doubt what he says, I just wanted other points of view.).

Anyway, I guess there is no alternative to trying it. I can try to get an (non-steam) iron, take scrap paper from someone else's laser printer and see if I can do any transfers.

I have very little discretionary capital, so I like to check things out carefully before I commit any resources. For example, that is why I merely looked through Al Williams' book in the bookstore instead of buying it, even though it looked interesting and even though, as books go, it is pretty reasonably priced. I know how badly wrong one can go by throwing money at a problem instead of investing thought in it.

Regarding Eagle, although I downloaded it, I haven't had time to experiment with it. I've been giving priority to my unfunded mathematical activities and they have been fairly intense lately.

It is possible to do serviceable 12/13 mil PCBs using LJ or IJ printer output as photo artwork.

Use a thin very transparent vellum (#1411 sticks in my head). Overhead transparency material doesn't work very well. You may have to play with ink density settings to get a good compromise between density and spatter.

Circuit Specialists sells photosensitive board that can be exposed in reasonable time with just a desk lamp.

It is very important to make sure the AW is in intimate contact with the PCB. A photographers' 'contact printing frame' is a great help.

They make a blue sheet that you print it on then iron on to the copper baord before etching, works pretty good. Don't know about a direct transfer...

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I have never found the toner transfer approach to be particularly useful.... there are too many ways to goof it up. Some people have great luck though. I suggest you look into a controlled heat source if you're going to do this.

Regards Brad

As Al Williams said in his posting and in his book, a certain amount of experimentation is required to get it to work, partly due to the wide variation in printers, irons and materials. Presumably it will work with any laser printer, so one is at least reassured that one doesn't have to keep buying laser printers until one of them works.

Irons are probably a lot cheaper than laser printers. Al Williams says to use an iron which is not a steam iron and not to use it with the heat set too high, if I remember correctly. I assume that any iron that doesn't have to be heated over coals will have heat control.

One thing that could come out of a public discussion such as this about the technique Al Williams describes is that particular combinations of printers and irons and other materials will be identified as particularly suited to the task, as well as more details of procedures. For example, this being an electronics group, it might be possible to add the capability to give actual temperature readings to an ordinary non-steam iron or to to make sure that it stays at a precise temperature.

I don't know what kind of controlled heat source BEVERNON had in mind other than a souped up iron.

Who are "they"? Is the blue sheet different from ordinary transparency?

Both DynaArt designs (now called pulsar) and Techniks sell special paper. And, an earlier question on 'what kind of controlled heat source'.... The only thing that I have come across that offers any consistency is a heat-press. DynaArt sells a heat laminator. However, with a laminator or iron you have to worry about deformation of the toner image .....

Brad

I did a google search for heat-press and came up with machines for transferring designs to t-shirts. They don't look cheap, but I didn't see any prices. I looked at the pulsar website and now I understand what a laminator is. They don't seem to sell them directly, as nearly as I can tell, but say that they usually go for $140, sometimes only $99, at places like Staples. That's good to know if one can't get the iron to work. Thanks for the info on this and the transfer paper.