How to Design PCB at home

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This article will explain the process of making a single layer PCB at home with the use of commonly available tools.

Ready to use PCB
Often people face problem while making a circuit on a bread board.
It is a common problem that the circuit may work some time and may not work
other time. Most of the time it is the connections on the bread board which
creates this problem. Either are connections are not proper or loose or may get
damaged while working or carrying the circuit on a bread board. Hence it is
always recommended to make the circuit on a PCB once it has been tested on a
bread board. 
 
A PCB has pre-designed copper tracks on a conducting
sheet. The pre-defined tracks reduce the wiring thereby reducing the faults
arising due to lose connections. One needs to simply place the components on
the PCB and solder them.

Materials required:

  • Over Head Projector sheet (known as Glossy sheets) or a wax paper.
  • Laser Printer.
  • Electric Iron.
  • Steel wool.
  • Two plastic trays.
  • Copper board/ PCB (eg: paper phenolic, glass
    epoxy, FR4, FR10, etc.)
  • Black permanent marker.
  • Etching solution (Ferric chloride).
  • Drill machine.

Step 1: Prepare a layout of the circuit on any commonly used PCB designing
software. A layout is a design which interconnects the components according to
the schematic diagram (circuit diagram). Take a mirror image print of the
layout on the Glossy sheet using a laser printer. Make sure that the design is
correct with proper placement of the components.

PCB Print on Glossy Paper

Step 2: Cut the copper board according to the size of layout. A copper
board is the base of a PCB, it can be single layer, double layer or multi layer
board.

Single layer copper board has copper on one side of the PCB, they
are used to make single layer PCBs, it is widely used by hobbyist or in the
small circuits. A double layer copper board consists of copper on both the
sides of the PCB. These boards are generally used by the industries. A
multilayer board has multiple layers of copper; they are quite costly and
mainly used for complex circuitries like mother board of PC.
 

Step 3: Rub the copper side of PCB using steel wool. This removes the top
oxide layer of copper as well as the photo resists layer if any.

Step 4: Place the glossy sheet which has the
printed layout on the PCB sheet. Make sure that the printed/mirror side should
be placed on the copper side of PCB.

Step
5:
 Put a white paper on the Glossy sheet and start ironing. The heat applied by the electric iron causes the ink
of the traces on the Glossy sheet to stick on the copper plate exactly in the same
way it is printed on the Glossy sheet. This means that the copper sheet will now
have the layout of the PCB printed on it. Allow the PCB plate to cool down and
slowly remove the Glossy sheet. Since it is manual process it may happen that the
layout doesn’t comes properly on PCB or some of the tracks are broken in
between. Use the permanent marker and complete the tracks properly.

Step 6: Now the layout is printed on PCB. The area covered by ink is known
as the masked area and the unwanted copper, not covered by the ink is known as
unmasked area. Now make a solution of ferric chloride. Take a plastic box and
fill it up with some water. Dissolve 2-3 tea spoon 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 as 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 for some more time in the
solution.

Step 7: Take out the PCB wash it in cold water and
remove the ink by rubbing it with steel wool. The remaining area which has not
been etched is the conductive copper tracks which connect the components as per
the circuit diagram.

 

Step 8: Now carefully drill the PCB using a drilling
machine on the pads.

 Step 9: Solder the components on PCB board carefully so that no layer connect with other layer.
Step 10: After soldering, your PCB is ready to work.


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