WEEK 8: 28th SEPTEMBER 2012

Title             : Designing the PCB (Printed Circuit Board).

Objective    : To design the PCB layout by printing the PCB                                 circuit, etching, drilling, placed the components,                             soldering the components and testing the circuits.  

Procedures: 1)   The design of a Printed Circuit Board (PCB)                                   layout of the system was printed on the                                             Overhead Projector (OHP) plastic.                                

                        Figure 1: PCB layout printed on OHP paper

                       2)   The masking tape had been used to stick the                                  printed OHP plastic with copper board and make                            sure there was no air bubble between both. This is                          the important step so that the circuit had been                                  transfer perfectly onto the PCB board without any                            broken connection.

   Figure 2: Masking tape had been stick with copper board

            3)   Then, a paper or cloth had been covered on the                     board to avoid the plastic melts due to the                             transparency of its hot iron. The iron had been set to             ‘Linen' or as high as the iron will go. A fairly hot iron               was needed because the toner had been forced to               melt and subsequently bond to the copper blank                   PCB.

Figure 3: Ironing the covered board

   4)   Then, the ironed circuit had been leaved for a while      to cool it down. Do not remove the masking tape          when the board still hot. After it cool, the masking        tape had been removed. The circuit that been iron      had been shown below.

Figure 4: The circuit after been ironed

    5)   Next the connection of the circuit had been check       by using the multimeter. The multimeter had been       set to ‘beep’ sound. The multimeter will produce a       ‘beep’ sound when the connection is connected to       each other. If no ‘beep’ sound was produce, the           connection might be broken.

Figure 5: The connection had been check using multimeter

   6)   The defects connection had been touch up by using    permanent marker pen 700 artline.

Figure 6: 700 artline permanent marker had been use to touch up the defects connection

  7)   Next, the etching process had been proceed by pouring some hydrochloric acid on a plastic container and soak in the copper board into the acid. The container then had been shaking slowly to remove the copper layout from the board.  

Figure 7: The copper board had been soak into the Hydrochloric acid 

           8)   Then the circuit board had been washed using clean            running water and been brushed with very fine grade            of sand paper. This will remove dirt, oils and other                contamination on the top of the PCB board. After                  rinse, the board had been dried quickly by wiping it                with towels wet with acetone. The wiping step had                been repeated as many times needed until the                      paper towel comes off completely clean. The board              had been dried quickly to avoid oxidization.

                         Figure 8:The circuit after etching

           9)   Next the etching circuits had been clean by rubbing              the circuit with very fine sand paper to remove the                copper layer. 

 Figure 9: The etching circuits had been clean with very fine sand paper

           10)   Then the circuit had been drill to make a hole for                    electronic component placement.

Figure 10: The circuit had been drill by using hand drill

Figure 11: The PCB board after being drilled

            11)   Next, the component had been placed by referring               the schematic diagram and been soldered.

Figure 12: The component had been soldered

 12)   After that, the component leg had been cut off by using a cutter. 

Figure 13: The soldered component's leg had been cut

 13) The connection of the circuit had been check again      by using multimeter. The multimeter had been set to    ‘beep’ sound. The multimeter will produce a ‘beep’      sound when the connection is connected to each        other. 

Figure 14: The connection had been check using multimeter

14)   If no ‘beep’ sound was produce, the connection           might be broken. The connection can be overcome     by soldering a little jumper wire on downside of the     PCB board to make it connected.

Figure 15: The jumper wire had been soldered to the defected circuit connection

Figure 16: The final PCB board after being through the above step 

Conclusion: Basically, the PCB process consisting six                               processes which are printing the PCB circuit,                         etching, drilling, placed the components,                                 soldering the components and testing the circuits.