WEEK 7 : PCB DEVELOPMENT (CONT'D)

4. EMULSION PROCESS




Now we continue to the next process of PCB Development which is Emulsion process. In this process we are going to use 10 gram of sodium hydroxide pellets mixed with distilled water. Mixed them well till sodium hydroxide pellets completely dissolved. Then soak the PCB into the solution and gently pan the pcb untill the circuit can be visible. 

sodium hydroxide pellets

panning process

After finished this process, we now move to the next step

5.  ETCHING PROCESS

By using the Etching machine that we have in PCB Room, we just have to put the PCB that already being emulsion into the machine and set the temperature to range of 40 - 50 degree Celsius. We used 44 degree Celsius and then we wait for about 4 minutes until the process done. Then after etching process done, we scrub the PCB till we get the layer. 

now we move to the next process which last process of this PCB Development

6. TROUBLESHOOTING PROCESS

The above mentioned exposure timing should be determined experimentally. But even when the exposure timing is correct PCB etching failures could happen because of low quality or too old photosensitive PCB, the photosensitive layer has aged despite the protective plastic layer. Other possible causes are too high concentration of development solution causing the photosensitive part not exposed to light to be dissolved by the sodium hydroxide solution as well. When developing too short not all of the copper of the PCB will be etched. Developing might take some experimenting to get used to it and know what to expect.

That's all for this week. We will update next process on next week. Thank you.