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DIY Laser Circuit Board

For the process I'll describe here, we'll need to print our board design onto a sheet of paper using a laser printer. Other types of printers will not work. Laser printer toner is actually powdered plastic, and we'll be making use of the fact that plastic melts to get it from paper onto the copper. In addition, the toner is able to protect the copper from the removal process. Yep, that meets the definition of resist; nice! With that in mind, it makes sense to have plenty of this toner stuff on the paper.

Black is not Black

Note: These color settings aren't required, but they do help produce a better quality board.

Black can be printed with a single black toner, or it can be a mix of the primary colors. Using graphics design software, its even possible to ask a color laser printer to print our black with a full coating of the three primary colors (often called rich black) and with a full coat of black toner. Obviously, this results in quite a bit of toner on the sheet - just what we wanted! If you look close, you can actually see that the toner is 'piled up' a few thousandths thick on the paper.

Having direct access to commercial color laser printers and the graphics software mentioned above, I can do this quite easily - but I realize most of my readers will not be as fortunate in that respect. However, most any local print shop with a color copier can do it for you. You'll just need to explain what you need them to do - its not something they've ever been asked for. What you will need is simply a color(even though its all black) copy printed from your file; prices will vary but less than $2 would be typical.

In order to get all the toner as described, your artwork file will need to be in what is called CMYK color mode, with all four of those colors set to 100%. If you have editing software that is capable of doing that, great. If not, the print shop you select should be able to convert your black to the desired color settings for a nominal artwork charge.

Mirror Imaging

Later in this process, we'll be turning our print upside down to lay it on the circuit board. Thus, it may necessary to create a 'mirror image' of the artwork. You'll have to think this thru as it can change depending on the point of view the artwork is drawn from. For example, I draw the traces as if I am looking at the component side of the board, pretending to look thru the board at the bottom copper. This does not need to be mirrored; in effect it will get mirrored when I turn the board right side up. On the other hand, my top layer of copper (if used) will need to be mirrored.

Print out a test copy of your art and lay it with the image against the board to see how this will work in your case. Mirror it as necessary.

What kind of paper to use

We'll want the artwork on a glossy paper as it has a very smooth surface. This smooth surface allows us to form a smooth coating of toner(resist) on our board, and helps it release from the paper a bit easier (we ultimately want it on the copper, not the paper).

I'm going to jump ahead a bit here, but what we are going to do in a later step is remove the paper by soaking it in water. Thus, we want to select a paper that doesn't hold up well to water.

I have experimented with many brands of paper. Of the ones my employer stocks, I've found that a paper called "Sappi Flow-Gloss 80# Text" works the best. Your selected print shop may carry this brand, and if so I recommend asking for it. Otherwise, I'd recommend asking for a few blank sample sheets of various brands; and see which one 'falls apart' fastest when you get it wet.

Plug for my Employer

If you happen to be local to Melbourne, FL; I'd personally be happy to help you get a print as described above at Action Quick Print. Otherwise, you'll just need to explain to the shop of your choice that you specifically need the blacks set to this color formula: "C:100 M:100 Y:100 K:100"; and ask for a mirror image if necessary(and you haven't already done so). One final note, ask them to print the artwork on the darkest setting available.

In the next section, we'll actually start working with the circuit board!