Sometimes it becomes necessary to make simple small printed circuit boards. Ordering their manufacture in the company is long and expensive, you can make them yourself. So, the process of making printed circuit boards at home step by step.
Let's consider the process of making printed circuit boards at home using a specific example. For example, you need to make two boards. One is an adapter from one type of case to another. The second is replacing a large microcircuit with a BGA package with two smaller ones, with TO-252 packages, with three resistors. Sizes of boards: 10x10 and 15x15 mm. There are 2 options for making printed circuit boards at home: using a photoresist and using the "laser iron" method. Let's use the "laser iron" method.
The process of making printed circuit boards at home
1. Preparing a printed circuit board project. I use the DipTrace program: convenient, fast, high quality. Developed by our compatriots. Very convenient and pleasant user interface, in contrast to the generally recognized PCAD. There is a conversion to PCAD PCB format. Although many domestic firms have already begun to accept in the DipTrace format.
In DipTrace, you have the opportunity to see your future creation in volume, which is very convenient and visual. Here's what I should get (boards are shown at different scales):
2. First, mark out the textolite, cut out a blank for printed circuit boards.
3. We display our project on a laser printer in a mirrored form in the highest possible quality, without skimping on toner. Through long experiments, the best paper for this was chosen - thick matte photo paper for printers.
4. Do not forget to clean and degrease the board blank. If there is no degreaser, you can walk over the copper fiberglass with an eraser. Next, using an ordinary iron, we "weld" the toner from the paper to the future printed circuit board. I hold for 3-4 minutes under slight pressure, until the paper slightly yellows. I set the heating to the maximum. I put another sheet of paper on top for a more even heating, otherwise the image may "float". An important point here is the uniformity of heating and pressure.
5. After that, letting the board cool down a bit, put the workpiece with the paper adhered to it in water, preferably hot. The photo paper gets wet quickly, and after a minute or two, you can gently remove the top layer.
In places where there is a large accumulation of our future conductive paths, the paper sticks to the board especially strongly. We do not touch it yet.
6. Let the board soak for a couple of minutes. Carefully remove the rest of the paper using an eraser or rubbing with your finger.
7. We take out the workpiece. We dry it. If somewhere the tracks are not very clear, you can make them brighter with a thin CD marker. Although it is better to ensure that all the tracks come out equally clear and bright. It depends on 1) the uniformity and sufficiency of heating the workpiece with an iron, 2) the accuracy when removing the paper, 3) the quality of the PCB surface and 4) the successful selection of paper. You can experiment with the last point to find the one that works best for you.
8. We put the resulting workpiece with the future track-conductors printed on it in a solution of ferric chloride. We poison for 1, 5 or 2 hours. While we are waiting, we will cover our "bath" with a lid: the fumes are quite caustic and toxic.
9. We take out the finished boards from the solution, rinse, dry. The toner from the laser printer is wonderfully washed off the board using acetone. As you can see, even the thinnest 0.2 mm wide conductors came out quite well. There is very little left.
10. Ludim printed circuit boards made by the "laser iron" method. We wash off the flux residues with gasoline or alcohol.
11. It remains only to cut out our boards and mount the radioelements!
conclusions
With a certain skill, the "laser iron" method is suitable for making simple printed circuit boards at home. Short conductors from 0.2 mm and wider are quite clearly obtained. Thicker conductors work just fine. The preparation time, experiments with the selection of the type of paper and the temperature of the iron, etching and tinning takes about 3-5 hours. But this is much faster than ordering boards from a company. Cash costs are also minimal. In general, the method is recommended for simple budget amateur radio projects.
