Soldering up components for a test run at the workshop, I ran out of time to implement something to actually attach to the end of the Z-axis servo. While I was setting up all the components with copious amounts of tape, I asked Emily for help. She has repeatedly demonstrated skill at creatively building a solution in very short time using whatever parts were on hand. The most important episode of this skill saving our bacon was when she fabricated a steering servo bracket for SGVHAK rover.
As I was focused on routing wires and taping them in place, I didn’t watch the magic happen first hand. But I was amazed when Emily walked up less than 15 minutes later with a bracket with parts clearly made of 3D printed plastic. There was not enough time to print such a thing… “How did you do that so fast?”
As it turned out, she drew from a box of rejected & failed 3D prints that was sitting in the back of the shop. The parts were not printed for this project, but their residence in the fail pile made them candidate raw material for today’s quick fabrication. Once Emily installed the Sharpie marker holder to our servo Z-axis, our plotter can lift its pen!
But as we found out very quickly, the lift is not clean. This cheap micro servo has a lot of slop which made it difficult to position it at a height that will make good contact with the paper when down and stay clear of the paper when lifting. Instead of ending a line cleanly, the pen would make a short diagonal mark as it lifted.
No matter, it was enough for us to continue testing this system. We started feeding it increasingly longer programs to see what breaks down first. Our answer: UGS, the G-code sender program running on our control console laptop, was the first to fail.