RepRap: Blog

A single LED from one of those cheap UV LED USB strip lights does indeed cure eSun Standard Resin in 5 seconds or less through a glass microscope slide. From directly under the glass it cures a patch 4.6mm x 3.6mm in a little lozenge.

The curing zone might spread out a bit when held further away, or at least I hope so because I need to cover a 4mm x 4mm working area. So I'll fiddle around with the right resistor to make it work with 12V and connect it to the RAMPS board on the output GRBL uses for a coolant pump. It shouldn't be too hard to fit between the two parts of the Maus XY Table, and then I'll have what I need to automate multiple resin layers.

Now, how to get the bloody stuff off the glass slide...

The output is now finished. This is Hackaday's "Jolly Wrencher" or a reasonable facsimile thereof. Took 1.5 hrs to plot out, one pixel at a time. The logo is 1.5mm on a side, 50 pixels per. Might well be the largest thing RepRapMicron has done so far, though I'm yet to test out the full 4mm x 4mm theoretical workspace.

So the "Maus" RepRapMicron mechanism still works, and the electrochemically etched nichrome tip that I bent stood up to it all. That's a relief. I could deposit at much finer resolution in resin as I can get down to 15-20μm per pixel with that rather than the rather ragged 30μm pixels that the mechanical process of chipping away Sharpie marker creates. Not so visible for debugging but.

Still, this PNG to GCODE converter works well enough. Might be a convenient way of testing the conductive/semiconductive resins for arrays of LEDs or sensors etc. when I finally get hold of some.

Here's the Maus in the process of doing the print. I'm using the mechanism described here and Arduino/GRBL electronics.

 

Just testing out the png_to_gcode generator I've put up on github at https://github.com/VikOlliver/RepRapMicron/tree/main/png_to_gcode and thought you might get a kick out of the "Hello World" I did with it to get my eye back in after a long absence. The points are on a 30μm grid, and Hello World takes 43 pixels, so that's [does maths] 1290μm - about 1.3mm in smug units, 5 one hundredths of an inch in Bronze Age units.

"Hello World" about 1.3mm wide

 

I did bend the etched tip and will have to make a new one, so I don't feel so bad about using the bent one to chisel away a layer of Sharpie marker in these tests. It actually worked well despite the kink, and I'm experimenting with it some more. Stopping the probe tip 10μm above the surface and lowering slowly the rest of the way definitely improves output quality.

Alright. Relatives visited and recovered, art commission finished ("Kaleidoscope" opens 24th April at Aratoi gallery in Masterton), and other than blowing up the 100W laser cutter life has returned to 'normal'.

Art project required some nifty small UV LEDs, which I have subverted a few of for the μRepRap to see if they will set resin. Just haven't got round to trying it.

 

I've also created some code to turn a PNG bitmap into GCODE point plotting, which currently doesn't have the dip pen stuff in it but I'll put that in under testing. Monochrome only at this point, though there's no theoretical reason why we can't use multiple resin types.