Monday, May 23, 2011

Electronics - In which the author learns to solder, properly

AAA wirewrap, who knew?
With the mechanical build in good shape, it was time to move on to the brains (mmmmm, brains). I bought all my electronics fully assembled as I've had very little experience soldering small circuits. I did however need to solder the header pins onto the stepper drivers. Many thanks to Shannon at work for patiently teaching me how to solder those parts correctly. I'm not ready for SMT components yet, but I feel fairly confident I can handle most through hole bits.

The actual install went pretty painlessly. After trying to come up with something clever and unnecessarily complicated to wire the Z axis motors together, I just used some small wire nuts to get the job done. One great thing I found was that the plastic binding from AAA TripTiks make great wire wrap. They're particularly flexible since the spine is very thin which makes them really well suited for the wire bundles that have to move with the X and Z axis. As you can see, I could use at least one more. Time to plan the next vacation, or at least pretend to.

Check out the copper heat sinks
I wanted to be able to mount my electronics boards in a way that they were fully protected, but still visible. I really love the look of those little copper heat sinks. So I designed an enclosure intended for clear sheet material, and coworker Brian bent it up for me out of lexan. There was just barely enough thread left on the bottom crossbar to let me attach it through the tab that's bent to match the angle on the smooth rod clamp by the fan. My soldering teacher then helped me find and mount the nylon standoffs for the boards, and I mounted and wired the 40mm fan I found in my stash. I'm very happy with the way it turned out. I think I'll even have enough room to mount the SD card reader when I get that far.

One thing that did trip me up for a bit was the pin config for the steppers. Looking at the plans for the RAMPS board, the color codes of various steppers (no two of which are alike), and the datasheets for my steppers, I could not for the life of me figure out for sure how it should be wired. Then I realized that since I had ordered both the motors and the board from Ultimachine, all I had to do was match the picture in their catalog. I still think there needs to be a way of noting in the RAMPS instructions which pins go to each coil on the stepper. No two color codes, letters, or number schemes are alike between manufacturers.

All that was left for me to be able to print my new companion cube (I wanted to make up for incinerating my last one) was to get the extruder assembled and fire up the software. Don't laugh, I really thought that was all I needed.

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