Printed Curcuit Board Design


You have an idea of some device and want to make it alive. Breadboard is the most convienient, fast and cheap way to put all elements together and make adjustments afterwards. Still, with more complicated projects, or for frequencies above 5-10MHz, a more 'professional' aproach is needed. I'm sure you have read a lot of articles about homemade PCB design, but here you can find a simple way to make Printed Circuit Boards with available materials.

This is the most famous method - using a laser printer/copier and the home iron.

First, get the copper plate with the dimensions needed.

Next, you have to clear it's surface from oxide, grease and dust - use a fine sandpaper, steel wool or an abrasive cleaning detergent. Wash with warm water and clean it with ethyl alcohol.

Now, I 'm sure that the plan is ready in your head, but think again. Decide how the elements will be soldered to the board. If they will be on the same side with the printed wires, you need a mirrored image on the paper. This kind of element installation is easier, for you do not need to drill holes, and can make adjustments afterwards. Also, this way you get shortest connections.
The other way - with the elements on the opposite side, makes the device more mechanically durable.
Leaving less surface for etching will give you less time and solution needed. Adjust the printer settings to a quality 600 dpi or higher.
Experiment with your printer settings. Even the cheap laser printers have different settings for various types of paper. For a heat transfer paper or a glossy one try "label" or "photo paper".
Avoid too thin wires or wires too close to each other - you can not get the factory quality with this method.
Print the circuit you want. Here, you have to experiment with what is available. The idea is to print the image on a paper and then to transfer the image on the plate. To do so, you need a LASER PRINTER. The choice of the paper is also important. Best results gives the special heat transfer paper. If you can not find such - do as EDI. I use the back side of a self adheasive paper, sold in almost any shop. Apply the toner on the back side - the one that preserves the adhesive layer.

Join the paper and the plate together and make sure the image fits correctly.

Remove the upper layer of the paper. The back layer is semi transparent so you can see how the toner is transferred and more importantly it is thin, so the heat from the iron more effectively melts the toner.

Apply the hot iron - the time and the pressure you apply is the things you have to figure yourself. Usually up to 3 minutes are ok. If you are not satisfied with the result - clean the plate again and start over.
A good practice is to use pre-heated iron on its MAX temperature, than apply the iron to the upper side for 10 seconds with a pressure. After that "iron" the PCB back and forth for 3-10 minutes, again appling pressure to the PCB.
Tip! If you heat with the iron the opposite side of the PCB first, you will get a better transfer of the toner from the paper to the plate.

Do not hurry. After applying the iron, leave the plate to cool by itself. Than, put it in a warm water for 30 minutes and than, as careful as you can, remove the paper.

Unless you are extremely skillful, or lucky, there will be some defects. Use a permanent marker to make it right

Prepare the etching solution in a non metal container, according to the instructions of the manufacturer and put the plate in it. The time for etching depends on the temperature, solution ratio and the surface of the plate that has to be removed. Note that no matter what solution you use, remember that you are working with a corrosive and toxic chemicals - use gloves, goggles and well ventilated space to operate with it.

When the etching is complete, do not forget to rinse the plate with hot water and soap.

Drill the holes for the elements, clean the plate again with a fine sand paper and ethyl alcohol and your Homemade Printed Circuit Board is ready!