RepRap: Blog

The objective of the test was originally to attempt to measure the height of deposited droplets by banging the probe into them and looking for bumpy motion using the 4K microscope. Unfortunately the probe was rather destructive, and I was unable to get anything out of it other than "well, it's 1-2 microns-ish". However, I happened to record the deposition process, and CC subtitled it for YouTube:

I doubt YouTube has done the original resolution justice, but even zoomed in on the original I could only just make out the droplets being deposited. This was all being controlled manually, and thus a wee bit haphazard. I set the CNC step size to 50μm and just slammed it around. Under software control, the probe is decelerated when it gets to within ~10μm and then is lowered gently, so those tend to be a bit more uniform.

As "measuring by braille" didn't work, I stuck the slide under the microscope horizontally and vertically. Here's the images but I couldn't determine much about the droplet height from it:

One of the big problems with imaging things at high magnification is that your depth of focus is about half a gnat's whisker. So even though there were 5 dots, I could only get two of them in focus at the same time. I could probably do a bit better if I made an improved swivelling slide holder, but that's a project for another day.