Preparation Before Making PCB
PCB design is usually done by converting your circuit’s schematic diagram into a PCB layout using PCB layout software. There are many cool open-source software packages for PCB layout creation and design.
Some are listed here to give you a head-start:
- Autodesk Eagle
- Designing a Circuit Schematic in Autodesk Eagle
p.s.In Eagle: File> Export>ImageBe sure to set DPIG to 1200 for better quality
Other Materials Needed for Making PCB
You also need FeCl3 powder/solution (same as etching solution), photo/glossy paper, a permanent black marker, a blade cutter, sandpaper, kitchen paper, and cotton wool.
For this tutorial, let’s consider making a PCB for a simple project- a Touch Switch using IC555.
Now everything is ready, let’s start making.
Step 1:Print the PCB Layout Image
Print the previously exported PCB layout on the thermal transfer photo paper. Note that you must print with a laser printer. Keep in mind the following points:
- You should take the mirror print out.
- Select the output in black both from the PCB design software and the printer driver settings.
- Make sure that the printout is made on the glossy side of the paper.
Cut the printed photo paper according to the picture size and prepare for the next step.
Step 2:Cutting the Copper Plate
Cutting Copper Plate
Cut the copper board according to the size of the layout using a hacksaw or a cutter.
Step 3:Rubbing Away The Top Oxide Layer
Rub the copper side of the PCB using steel wool or abrasive sponge scrubs. This removes the top oxide layer of copper as well as the photoresist layer. Sanded surfaces also allow the image from the paper to stick better.
Make It Smooth
Step 4: Transfer the PCB Layout Print onto the Copper Plate
Method 1: Iron on Glossy Paper Method (For Complex Circuits)
Transfer the printed image (taken from a laser printer) from the photo paper to the board. Make sure to flip the top layer horizontally. Put the copper surface of the board on the printed layout. Ensure that the board is aligned correctly along the borders of the printed layout and use tape to hold the board and the printed paper in the correct position.
Place The Printed Side of The Paper On The Plate
Method 2: Circuit by Hand on PCB (For Simple and Small Circuits)
Using the circuit as a reference, draw a basic sketch on the copper plate with a pencil. Once your sketch looks good, trace over it with a permanent black marker.
Use Permanent Marker To Sketch PCB
Step 5: Iron It!
- After printing on glossy paper we iron it image side down to the copper side. Heat the Electric iron to the maximum temperature.
- Put the board and photo paper arrangement on a clean wooden table and clothes with the back of the photo paper facing you.
- Hold one end of it by the Towel and put the hot iron on the other end for about 10 seconds. Now, iron the photo paper all along using the tip and applying little pressure for about 5 to 15 mins.
- Pay attention towards the edges of the board – you need to apply pressure, do the ironing slowly.
- The long hard press seems to work better than moving iron around.
- Here iron heat melts ink printed on glossy paper and gets a transfer to the copper plate.
Iron The Paper
CAUTION: Do not directly touch the copper plate because it is very hot due to ironing.
Step 6: Peeling The Paper
After ironing, place the printed plate in Luke warm water for around 10 minutes. Paper will dissolve and remove paper gently. Remove the Paper off at low angle & traces.
Peeling The Paper
In some cases, while removing paper some of the track gets fainted.
See figure in white box black line track is light in colour hence we can use the black marker to dark lighted track as shown in the image.
Darkening The Trace
Step 7: Etch the Plate
You need to be careful while performing this step.
- First, put on rubber or plastic gloves.
- Place some newspaper on the bottom so the etching solution does not spoil your floor.
- Take a plastic box and fill it up with some water.
- Dissolve 2-3 teaspoons of ferric chloride power in the water.
- Dip the PCB into the etching solution (Ferric chloride solution, FeCl3) for approximately 30 mins.
- The FeCl3 reacts with the unmasked copper and removes the unwanted copper from the PCB. This process is called Etching.
- Use pliers to take out the PCB and check if the entire unmasked area has been etched or not. In case it is not etched, leave it in the solution for some more time.
Etching The Plate
To make the board etch evenly, you can gently move the plastic box to and fro so that the etching solution reacts with exposed copper and form iron and copper chloride. After every 2-3 minutes check whether all copper is etched or not.
Step 8: Cleaning, Disposal, and the Final Touches for the Circuit Board
Be careful while disposing of the etching solution, it’s toxic to fish and other water-based organisms! Don’t even think about pouring it in the sink when you are done, it is illegal and might damage your pipes. Instead, dilute the etching solution and then throw it away somewhere safe.
A few drops of thinner (nail polish remover works well) on a pinch of cotton wool will remove completely the toner/ink on the plate, exposing the copper surface. Rinse carefully and dry with a clean cloth or kitchen paper. Trim to final size and smoothen edges with sandpaper.
Remove the Ink
Now, drill holes using a PCB driller like this PCB driller and solder all your cool components to the board. If you want that traditional green PCB look, apply solder resistant paint on top PCB lacquer. And finally, your super cool circuit board will be ready!