Before you start, you should know that there are companies that are dedicated to manufacturing these custom printed circuit boards for you; You just have to send them the design and they’ll take care of the rest, which will make things a lot easier, albeit at a cost. However, in this tutorial what we are going to teach you is to make a custom PCB at home, although it is true that of course you will need to have some. tools that, really, not everyone has at home in a normal way and, therefore, is aimed at amateurs DIY (do it yourself, do it yourself) who already have some knowledge of it.
What is a PCB and what is it used for?
PCB means Printed circuit board, also called electronic card or printed circuit board. It is a surface made up of paths, tracks or buses of conductive material laminated on a non-conductive base, that is to say that it is in reality only a connection plate on which the components of the device to be manufactured can then be welded. . You could say that, for example, a PC motherboard is actually made up of a huge PCB.
Printed circuit boards are used to electrically connect different electrical components through conductive tracks, while mechanically supporting all of the components by means of the non-conductive board.
For example, we could make a PC motherboard by simply connecting all the components directly with cables, but besides being a huge connection mess, everything would be “on air” with nothing to support it; With a PCB, everything is organized, with easy access and also on a solid and resistant surface.
The PCB manufacturing and the assembly of components is generally automatic, allowing its mass production and making the assembly much more economical and reliable. However, that doesn’t mean that you can make your own PCB at home if you have the right components and enough skills to do it, so let’s see what it would be like if you did decide to do it.
How to make a custom PCB
Obviously the first thing to do is PCB layout, which can be more complicated or simpler depending on how you use it (it depends on you). You can use programs like EasyEDA O PCBWizard, but also with very advanced tools such as Autodesk Eagle. We are not going to go into the software part, but of course you need to have the electrical diagram ready to know how to make the custom PCB beforehand.
Una vez que tengas el diseño hecho en el software, necesitarás una impresora láser para imprimirlo (ojo porque para esto no vale una impresora de inyección de tinta por los sedimentos que deja en el papel) en forma de espejo y debes losegimesurarte de que imprejo y debes losegimesurarte de que in one glossy finish paper (You can reuse, for example, the cover of a magazine for this).
Once you have it ready, you will need a piece of CEM copper cut to size to fit the model you just printed. You need to make sure that the copper surface is as smooth as possible and that it is perfectly clean; To do this, clean it well with a scouring pad and dish soap, rinse it and dry it completely with paper towels or a dry cloth. Once dry, wipe the entire surface with rubbing alcohol to remove any remaining residue.
Now comes a very delicate step because the quality of the circuit board depends on it: on a folded sheet, as the following picture shows, you need to place the copper piece and the circuit diagram on top of it; We remind you that it is important that the paper has a glossy finish and that the printing was done with a laser printer, and in the next step you will see why; Place the side to be printed on the copper foil and fold the paper.
Now what you need to do is place it (try not to move) on a smooth, hard surface that doesn’t burn easily, like a wooden board, and literally iron it with an iron on full power. With this what we will get is that the impression of the circuit design comes off the shiny surface that we used, and with the heat it is transferred to the copper foil.
With about 5 minutes, the application of heat (or less, depending on the strength of the iron) will be sufficient. Then very carefully and with protection you need to put the copper foil with the glued paper in cold water so that it peels off.
When it cools you can remove it and when you remove the paper you will see that the print has been engraved on the copper plate. If you see that the print of the diagram has not been completely transferred to the copper plate, you can run through the lines or dots with an indelible marker, preferably black (so that it appears more on the surface).
Now you need a little chemistry, and for that you will need hydrogen peroxide, citric acid powder Yes sal fina common. In a plastic container you need to add 100 ml of hydrogen peroxide, 30 grams of powdered citric acid and 5 grams of salt. Stir thoroughly (don’t worry, it’s not poisonous) until well combined.
You must now leave your copper plate in this solution that we have created; A chemical reaction will occur (which you can speed up if you heat it up a bit) and you will see the electronic board start to bubble slowly and turn green (no, PCBs are usually not green because of this) and after a while time, blue.
The green / blue color is due to the chemical reaction separating the copper from the CEM board, and you will know the process is complete because the board is now translucent. It should look something like this, and you will see that the black print (and / or the permanent marker) is precisely such that the copper part underneath prevails over the chemical solution. In other words, now the translucent part is not conductive but the black part is.
You practically have your custom PCB ready, but now you will need to precisely remove the toner / marker, and for that you can just do it with a cotton ball and alcohol. You will see that under the black, the conductive copper appears.
You can now use a small drill or an electric punch (more recommended, actually) to punch out the points where the components need to be welded.
Although we have already made copper lines and they are conductive, it is advisable to review them using tin using a soldering iron.
Once this is done, your custom PCB is already completely finished and you can solder the components you need based on the design you made.