Friday, September 18, 2026
Small Square Tip test, Take 8
Getting closer. The previous tips were far too finely pointed and were depositing micron or sub-micron dots of resin that I had difficulty positively identifying. This ogive point etch is way too efficient! So I manually took Probe #14 and blunted it a lot by dipping it 30-40 times in the meniscus of the electrolyte etch.
This produced the following tip, which I very enthusiastically drove into the glass slide. I was trying to make absolutely sure I had contact because I could not see the droplets in the USB microscope. I could not get good images on the binocular microscope and had to take the following micrographs of dots with the bench microscope:
The dots are in wavey lines because the tip displaced during my enthusiastic touchdown attempts. The dots appear to be approximately 4μm in diameter. As I want something closer to 10μm or more this tip is still to pointy. Great for etching and very fine detail, but not for building robust microscale tools.
For reference, the resin reservoir only made it up half the smooth part of the point, so about 150μm deep:
I'm going to have to try an even blunter tip. Last time I did this by putting a freshly-cut wire 20mm deep in the etch, which notes say produced a very rough point that had to be smoothed off by a quick dunk on the surface. So that's the next experiment.
