RepRap: Blog

When removing the previous probe, the one with the touch indicator on it, I realised I didn't have anywhere to put it! So, I've uploaded a newer version that has a tip cover that can be attached using a screw.

I'm going to have to construct some kind of enclosure for the μRepRap, as I'm having problems with sunlight prematurely curing the resin during a print. The tip on the probe in the picture above is in fact caked solid.

Progress too on the RepRapMicron mailing list software, "listomail", which now supports the redistribution of file attachments to the mailing list. I've yet to add autoreply detection, and the IMAP handling relies on tickling the IMAP timeout with NOOPs too much, but I think the list server script is now sufficiently reliable for regular use. So pipe up if you want to join the email list.

Fired up the μRepRap after nigh on a month, and after damp weather following an air conditioning failure. Still in good alignment, so I had a go at a resin print.

As expected, the steeper angle on the probe used produced a bigger droplet size (hey, it was what I had fitted at the time). This may seem counter-intuitive, but I've seen this before and  I suspect that a thicker probe tip pulls more resin back due to capillary action. The deposited first layer was approximately 8-10μm thick. Here's a shot of me doing a few tests of micromugs:

The takeaways from that run are:

Raking light from the top camera (now angled in at 45 degrees or so) is causing reflections at the contact point between the resin and the slide. This was a suggestion from a fellow Fab Labber. This, together with the 4K microscope, allows coated probe contact to be visualised relatively easily compared to previous efforts.

The first layer appears to be substantially thicker than subsequent layers. This is a slight problem, because current slicers all let you set the thickness of the first layer by determining the standoff distance to the bed for the first layer, and with μRepRap, the layer always starts at zero. Prusaslicer does seem to have individually configurable layer heights though, so I'll have to play with that.

Eventually this is going to need custom software, but I currently don't have the resources to manage that and I'll have to fake it.

PS I'm feeling fine now, but have to go back in hospital in a week to be introduced to some tiny little cameras so they can figure out WTF is going on. I hope they're narrower in diameter than my microscopes!