RepRap: Blog

Looking carefully at the results of the previous print test, I noted a weird thing: A double line drawn in the resin was solid, while single lines tended to bead up. The beading of the resin like this was observed in the very first resin-dragging probe tests here. I wondered if there might be a line width at which the process of curing the no-name resin causes it to contract. A simple experiment was conducted  to see if some new resin did the same thing.

Using a new bottle of eSun Standard Resin, I placed a droplet of resin using a wiped, blunt probe onto a microscope slide. It spread out to 6mm diameter. Then, using a 0.5mm hypodermic I drew out a few trails of resin, and checked with a microscope that very fine trails had been drawn out. I cured the resin, and looked again.

There appears to be a point, somewhere below 10μm, where the resin will pull itself into beads as it cures. However, the eSun stuff seems to be a bit more stable than my earlier no-name batch, so I'll have to re-run the test with the triangles.

Here's a not-very-good screenshot at maximum magnification of my camera setup. I copied a 20μm square from a calibration slide shot through the same lens. You can only just see a fine trail (it's a lot clearer with the naked eye) to the right of the calibration square, which is about as fine as I can go before things blob up.

I really need to find a way to dye the resin to make photography easier. I have tried fluorescein but that does not seem to be resin-soluble. I have no idea what the height is, as I have no way to measure it. This may also be important. Dunno.

So, some fiddling to go, but 10μm features would appear to be possible with the new eSun resin. Stay tuned, folks.