This week has produced probably the most physical progress to date.
What I’ve Done Since Last Week:
Monday: With one 4″ x 4″ plate tested and cut, I started off in the morning by cutting the other 4″ x 4″ plate just to build up my confidence before I cut the 6″ x 6″ plate that afternoon. I built the wooden bracket to hold the plate in place, zeroed the axes (x and y are always done manually while the z—up/down—axes can be zeroed more precisely with the metal zeroing plate), and I started to cut the piece. What happened was the bit went way too deep and cut all the way through, ruining the plate. I figured out that it went too deep because for some reason the zeroing plate zeroed the z-axis totally wrong.
Tuesday: Knowing that the zeroing plate was the reason that it went too deep, I decided to zero the z-axis manually. I put a new plate in the bracket, and very carefully and as exact as I could get, zeroed all of the axes. This worked perfectly, and I had my first (of two) 6″ x 6″ graphite plates.
Wednesday: I only ordered two 6″ x 6″ plates, and since one was ruined, I had to order more. So in the mean time I had to figure out something to do. I secured the endplate material on the base of the CNC, but I did not have the proper bit to cut hard plastics, which I ordered as well. I decided to pull out the rubber for the gaskets and cut them to size. I measure and cut four .9″ x 6″ pieces that go on either side of the 4″ x 6″ piece of metal (I’ve yet to discuss this, so don’t worry if you have no clue what I’m talking about) that sits between the endplate and the graphite plate, and two 6″ x 6″ pieces that I will cut a 4″ square from the middle that sandwiches the MEA. I needed to make 1/8″ holes in the rubber, so I ordered a leather puncher that can do the job.
Thursday: I was actually home sick today, but neither the graphite plates or the hard plastic drill bit had come yet, so I spent my time catching up on blogging.
Friday: In the morning, I quickly punched out the holes in the gaskets with the leather puncher. Though the both the drill bit and the graphite plates had arrived, I thought it would be better to start with those on Monday. So I began the side task of coding and wiring a hydrogen sensor that will come in handy while testing to make sure there are no leaks and for my final product as a safety feature. I coded it, set warning limits that beep obnoxiously if the hydrogen concentration in the air (measured in parts per million) gets too high. That was started and completed in the afternoon and evening.
What I Plan to Do This Week:
Monday: Now that I have the new graphite plates, I can definitely cut the other 6″ x 6″ relatively quickly, and if for some reason it goes wrong, I have a backup. So the second plate should be done by Monday.
Tuesday: What I have yet to blog about is that I plan to change the design of the endplates. Right now, they are 6″ x 6″ so they are exactly the same size as all of the other components. What I want to do is actually make the endplates bigger, say 8″ by 8″ inches for three reasons. One, it gives an inch on all sides so that when it is set on a table, or god forbid it was dropped, all of the inner, more fragile components will be safe. Secondly, the metal plates that collect the current has to have a little piece sticking out so it can be connected to a circuit. It would be exposed if the endplates were 6″ x 6″, but if they are 8″ x 8″ it would provide protection for this piece. And thirdly, with the original 6″ x 6″ endplates, there is a hole in each corner that goes through the entire cell that will be used to fasten the cell together. This is okay, but If the endplates were 8″ x 8″, I would keep the original fastener holes that are for the 6″ x 6″ plate, as well as add four support rods in the corner of the 8″ x 8″ that would just go from endplate to end plate, making the entire cell more secure while also adding more protection for the inside components. And fourthly… I think it’ll look way cooler. So I will start redesigning the endplates Tuesday and hopefully finish and have the new version ready to go by Thursday.
Wednesday: Continue redesigning the endplates as well as figure out if/what materials I need to order and order them—I am pretty sure that I will have to order another sheet of garolite because I only have 12″ square which means I can only get one endplate out of it.
Thursday: Hopefully by Thursday, I will be done redesigning and have ordered all of the parts. If I am done, the I might be able to cut out one endplate! If not, Friday.
Friday: By the end of Friday, I should have one plate done and all of the necessary materials en route so come Monday, I can quickly do the other one.
Hope all goes according to plan!