ETCHING PROCESS

WEEK 24

5 week to goooo.....!!! 

In this week, the objective that need to be achieved in this week is to make sure that the etching process had been done. The first step in this week and to complete the first objective in this week is to produced the PCB board and the etching process must be done. Below picture shown the step by step in developing the PCB 

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 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 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: 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. Allow the PCB plate to cool down and slowly remove the OHP 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 5: 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

Step 6: Take out the PCB wash it in cold water and remove the ink. The remaining area which has not been etched is the conductive copper tracks which connect the components as per the circuit diagram.

Step 8: Once all the copper is gone rinse it in the water bath, let it dry and use rubbing alcohol to whip off the ink transfered onto the PCB and PCB already DONE!!