Clear Case Prototyping

by Ben N on April 7, 2012

Yesterday, I finally got a chance to head down to the Milwaukee Makerspace and use the laser. No easy task just walking in to the place carrying an Open Revolt controller while on crutches…

Once I was seated at the laser station, I started work playing around with cutting some parts. I already played at home with some paper templates. Right off the bat, I noticed a change or two I was going to have to make, but unfortunately, the printer at the Makerspace was down! Doh!  There was some thinner plastic material right at the laser station, so I thought I would experiment with cutting some pieces out of that.

With the material being thinner than what is planned for, the tabs don’t come out flush, but stick out too far instead. Oh well, good enough for just testing this all out!

I did have to widen the space between the B+ & B- bars. It was just a little too narrow to slide on. On the M end, I made the bus bar hole just a little bigger, because that end has some shrink wrap on it.

The engraving of the logo on the middle top part looked pretty good. I mirrored it, and the top piece is symmetrical, so I didn’t have to do anything like cut the piece, then flip it, THEN engrave it. I also played around with mirroring the text of the bus-bars so that they were cut from the inside as well.

The B+/B- end cap is “double-marked”. I forgot to double-check where 0,0,0 was on the laser. One downside of donated/loaned equipment is that it’s not always in perfect condition. In this case, the laser doesn’t always start from the very upper left corner. It’s not a huge deal, but you do need to double-check it before starting to cut out a piece.

In the assembled photos of the prototype case, I just used a few pieces of Scotch tape to hold it together. The spacing of the notches was pretty good. There was some friction there, but not so much it couldn’t fit together. I also tested the notches against the thickness of the material I plan to use for the finished case design, and that looked pretty good.

In the “things I learned from doing this…” I do need to make the case about 1/4″ taller. One of the components on the logic board pokes up just a bit higher than the rest, so I need to account for that. Also, the logic board is 6″ wide on one end, but 6&1/8″ on the other. I need to widen the case just a tad. I also have to raise the hole for all the wires just a tad. It should be just a little bigger too. I was able to fit all the wires through, but it was really tight.

I also liked how the logo lined up in the middle of the controller. Looked pretty good!

I did try some test cuts of the thicker material, but didn’t have much luck. I managed to melt it, scorch it, and yes, even start it on fire, but not actually CUT through it. Looks like I’ll need to check with some of the guys about suggested laser settings for cutting the .22″ material.

While I was at it, I did a little laser etching on the Leatherman that Instructables sent me. While the laser isn’t powerful enough to etch metal, it’s great at taking anodization OFF of metal, revealing the metal under it. I used this same technique on my travel coffee mug, and it worked great.


In further news, do not allow the toddler near any prototyping. Nothing good can come from it, as the toddler tries to eat anything within reach. Hopefully, the finished case will protect the MOSFETS from baby drool! 

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