Week 7

Not too much to report this week. Continuing from last week I finished drilling the switch board. Slight problem with a blunt drill bit that was burning the board. After replacing that, the drill did slip a bit giving me an unwanted hole in my board. Luckily it won't effect the board.
After this I continued to solder all 3 boards. The greatest difficulty was the switch board's actual switches. It was difficult to accurately line them up and solder them straight. There is some discretion between the switches. But I'm happy with the end results of all 3 boards. Visually there doesn't seem to be any problems, possibly too much soldering causing a slight blob, other than that, all connections look fine. Attached below are pictures of the results, front and back. Next week moves onto the testing of the boards.


Soldered multiplexer board

 



Soldered Switch board



Soldered ADC board







 

Week 6

Precious little time available in the lab this week, so I went about creating a new switch board straight away. I followed the same procedures as before as my initial switchboard came out fine from the chemical tanks last week. The only problem was that the tanks had to heat up and my board had to be left in the etching tank for 60 minutes. It was a little frustrating, so not to waste any time, I started soldering parts onto my ADC board. Going back and forth to the etching tank to check on my board, I accidentally soldered one of my connectors on the ADC board the wrong way round. This had to be removed and re soldered. I eventually got my switch board out of the etching tanks and proceeding tanks and went about drilling it, first taking it soft and gentle with the slight tapping for the indentations for the drilling!! Lab time was up, I got only about a quarter of the way through drilling the board, I will need to complete the drilling next week.

Week 5

This week was further developing the ADC board. Having created the PCB design the board was now ready to be developed. This is done the same way as the multiplexer board. First the exposure in the UV machine, then into the developing tank for 6 seconds. Then on to the Etching tank. As per usual the etching tank took longer than it should. Considering it is a single sided board, and there was a lot less copper to be removed, it still took 30 minutes. The photoresist stripping and tinning went as planned. I was happy enough with the result, the thinning looked dull in some places but the design seemed solid.
The next step I took was to make the Switchboard PCB so that I could drill and solder all the boards together. We were given the design of the switch board, I just followed the same procedure as before with the chemical tanks the results were good. The resulting board being the best board to date.
Next up was the drilling. I started with the switch board. Firstly you tap were its to be drilled to create an indentation so that it will prevent the drill from slipping. Unfortunately, I was a bit heavy handed with the tapping and applied too much pressure on the board marking the indentations a lot more than needed. I then drilled the board using 0.8mm and 1mm drill bits were needed. Because of the heavy tapping on the board, the drilling started to strip away some of the circuit lines. My hope was to fix this with some soldering. Learning from my mistake, I was a lot gentler with the ADC board, the results were much improved. At this stage we were given a manufactured multiplexer board, so there was no need to drill my one.


Pic1: Damaged switchboard

 Soldering next, and this is were things started to go wrong. With the time nearly up in the lab, I tried desperately to rescue my switch board to no avail. I couldn't reconnect the damaged circuitry and I even burned the board with the soldering iron. Having being my best board from the chemical tanks, I've now managed to destroy it with hammering and soldering, see pic1. I then decided to remake a switch board, but that will have to wait until next week.