WEEK 5

TITLE:

Fabricating the actual Printed Circuit Board

OBJECTIVE:

To fabricate the actual Printed Circuit Board

DISCUSSION/ANALYSIS:
After I had been to Jalan Pasar last week, I can make the actual PCB of my driver circuit. The step are shown below:

Step 1:

Take a mirror image print of the layout on the OHP sheet using a laser printer. Make sure that the design is correct with proper placement of the components.

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 multilayer board

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 OHP 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 OHP sheet and start ironing. The heat applied by the electric iron causes the ink of the traces on the OHP sheet to stick on the copper plate exactly in the same way it is printed on the OHP sheet. This means that the copper sheet will now have the layout of the PCB printed on it.

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 for approximately 30 mins. The ferric chloride 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

Below is the PCB layout that I had fabricate.

Front Actual PCB

 Back Actual PCB

CONCLUSION:
I had successfully fabricate the PCB of my circuit driver.