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Etching/Prototype Process:

After completing the schematic and breadboarding a working model, we moved on to etch a prototype board too physically. We used a kit provided by Mr. Kliewer. It had pc boards on one side with copper plating on the back. The idea was to place a special kind of tape on the copper side where the traces were going to be with little stickers with holes in the middle for pins.

After placing the desired traces of the board on the copper side, we then put the whole board into FeCl₂to wear away the copper but leave behind the copper under the tape to make a complete board where then one would drill holes and solder in components and have a working prototype for a pc board. Theoretically, it sounded very ideal; but when we sat down to do it, we quickly found it was extremely complex and methodical. First, we had to draw the design on the copper side then trace it over with the special tape. After the tape was placed on the copper side with all the pin pads in the correct spots, we then had to place it in the FeCl₂for about two hours. Then after taking the board out, we were to strip the tape off and the copper traces were supposed to remain. A few problems arose. 

First, drawing out the design was excruciatingly difficult, as we had to draw out our highly complex design with only one layer of copper to deal with, making the drawing process very agitating. Secondly, we did not realize how sensitive the tape was, meaning it lost its adhesives with any sort of liquid, including fingerprint oils. The only way realized this problem was when we removed the tape off, revealing that some of the tape had fallen off, revealing cut or oxidized traces. Furthermore, our initial design, as we found out, was not going to work so we had to come up with a new layout that was twice as small. This resize proved to be twice as agitating due to the limitation of space to draw, then tape. After three hours of agonizingly drawing out the new layout without touching the copper, we set it in the FeCl₂for a few hours.  

After it was completed, we found that the FeCl₂ had still seeped under the tape, wearing away at some traces and oxidizing them. There were so many deficiencies that we had to retrace the whole board with solder. Upon completion, we soldered in the components, added power, and it worked. We somehow managed to make the prototype work with all the obstacles and blunders we encountered the first time.

For questions and comments contact prhsinventeam@gmail.com.  All material herein are subject to copyright laws ©  2007.
Last updated: March 29, 2007.