In the world of electronics, PCBs or circuit boards are the most integral part of any electronic device. They are often disregarded since they are hidden underneath the electronic device’s shell but they are indeed the backbone to any appliance, electronic gadgets and devices you own. The PCB (printed circuit board) houses all the electronic components of a device and electronically connects each other to create a circuit. It is rightfully designed to keep all the electrical wires fixed and other components in place.
If you are into electronics manufacturing, it would be no surprise if you are wondering how to design a PCB board and you are most likely eager to know PCB design steps. Even though you can always purchase ready-made circuit boards, it would be too expensive most especially if you are only a small electronics business. Doing it yourself is definitely the way to go as a small-time electronics manufacturer.
There are 3 different ways on how to design a circuit board;
- Circuit by hand
- Iron on glossy paper
- Laser cutting method
The laser cutting method is the top technology used in the industry when it comes to creating printed circuit board designs. It requires laser machinery which is too expensive for small and even up to mid-sized businesses. In this wiki article, let us focus on the other two methods on how to design a PCB board: circuit by hand and iron on glossy paper.
Step by Step Process on How to Design PCB (Circuit Board)
First things first, you need to draft your circuit’s schematic diagram before thinking of putting it on to the circuit board. Fortunately, there are already a lot of free software out there who can take care of the PCB layout design. Some of them are paid packages who can give in-depth outlook to the PCB layout design and it would be up to you whether you’d pick the free or paid ones.
Once the PCB layout design is ready, you now have to secure the materials needed as part of PCB design guidelines. Here are the materials you need;
- Copper plate
- Etching solution
- Glossy paper
- Black marker
- Kitchen paper
- Cotton wool
- Steel wool
For this sample on how to design a circuit board, let us consider making a PCB design for a simple touch switch device using IC555.
1. Have a printout of your circuit board layout.
Have your circuit board layout printed using the glossy paper and make sure the print is on the glossy side of the paper. Choose the output in black on both from the PCB design layout and the printer’s settings.
2. Cut a copper plate for the PCB.
Cut the copper plate according to the proper size of your PCB layout. The smaller the plate will be better for the overall outcome since we want to keep things small and minimized but at the same time spacious to keep all the electrical components.
Rub the copper side of the PCB with a steel wool to remove the oxide layer of copper along with the photoresist surface. Having a smooth surface allow the image from the printout to stick better.
3. Transfer the printout on to the copper plate.
Transfer the printout by putting it on the copper surface of the PCB and ensure the board is properly aligned on the borders. If necessary, tape the printout on the board to hold it in the right position.
For the next step, here is where it becomes a two-way street since the two different methods on how to design a PCB board mentioned above will come into play.
a. Circuit by Hand
While referring to the circuit, trace the circuit board layout on the copper plate using a pencil. Once you are satisfied of your sketch, retrace it again with a permanent black marker.
b. Iron on Glossy Paper
This is the other method wherein you iron the printed glossy paper side down on to the copper side of the plate. Simply put the glossy paper on top of the copper plate with the back of the glossy paper on the surface. Use a pair of pliers to keep the glossy paper and copper plate in place then put the flat iron on the opposite end for 8-10 seconds. Repeat the process for other surfaces and just move around your grip on the pliers to keep it in position.
Once you have covered the entire gloss paper surface, iron the gloss paper all along the edges with a little applied pressure for 10 to 15 minutes. This ironing process transfers the ink on to the copper plate due to the heat. Be wary of the copper plate’s hot surface due to the hot iron.
After ironing, put the copper plate in lukewarm water for 10 minutes. The paper will right away dissolve making it easy for you to peel it off. However, there are times when the ink gets fainted after peeling but you can easily solve it by tracing it all over again with a black marker.
4. Etch the plate.
This is arguably the most crucial step on how to make PCB: the etching process. You have to be very careful during this process by first putting on sanitary gloves for protection. Put some paper on the bottom end so the etching solution will not leave marks on the floor. Meanwhile, fill a plastic box with water then dissolve 2-3 teaspoons of your etching solution popularly ferric chloride in the water.
Submerge the PCB into the solution and leave it there for half an hour. The etching solution reacts with the copper surfaces removing the copper with no marks on it from the PCB. In case it is not properly etched, leave the board again in the solution for a few more minutes. Take out the useless copper with a pair of pliers.
5. Cleaning and final touches for the PCB.
The etching solution is very toxic and you have to dispose it properly. Do not simply drain it down your sink since it may damage your pipelines. Instead, dilute the solution with more water and throw it somewhere outside your house.
To remove the remaining ink on the PCB, a few drops of thinner on a slab of cotton will get the job done. Simply rub it on the surface then rinse carefully with water and wipe dry with a cloth or kitchen paper. Trim the board to your desired size then smoothen the edges through sandpaper.
For the final step, drill holes on the printed circuit board design using a PCB driller. Use a soldering iron to attach all your cool components to the board. If you want the traditional green-colored printed circuit board design, apply solder resistant paint on top of some PCB lacquer.
Carefully follow these PCB design guidelines and now you have your DIY cost-efficient PCB or circuit board. The casing for the PCB is usually done by starting out with 3D design and continuing with plastics manufacturing.