RepRap: Blog

The FPath Project is an R+D effort to follow the Feynman Path to Nanotechnology - the use of tools to build smaller tools which then build smaller tools and so on. The ideal situation would be the eventual development of kits of tools and techniques applicable to various scales (sub-millimeter, micron etc). 

In order to bias the direction of the FPath Project experiments towards this goal, a series of challenges has now been created - each of which solves a useful problem. 

http://www.ofitselfso.com/FPath/SubMillimeterChallenges.php 

The FPath Project will attempt to complete each of these challenges - but they are generally open to others. If you complete a challenge (or even make a valiant attempt) I am happy to post a link to your solution on the the Results Page.

New Challenges will be added in the future and suggestions are appreciated.  

Labels: Additive Manufacturing, Feynman Path, Nanotechnology

I can now sit at the desk again for a bit, and slide things around the bench. Tremor from blocker pills is fading, and I can manipulate tiny things. So I've shuffled the μRepRap under the binocular microscope:

 

This gives me an enormously better view. Erm, 3 wee issues:

1.    While binocular vision is very nice, I can't share it on the blog.

2.    When looking into the binocular microscope, I can't operate the CNC jog controls.

3.    I can't bend over to look through the eyepieces for very long right now.

4.    It does rather get in the way, doesn't it? 

 

I'm collecting ideas for when I'm declared fit again:

Cheat like hell to get a useful micron-sized tool. 

Etch a pattern into some Sharpie or other masking material, then drop resin on top, then expose the resin through the etched Sharpie mask.

Try the old "write on a grain of rice" trick.

Nail some CNC joystick control software that allows constant acceleration with an analogue stick.

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!

Last few days have been interesting. RepRapMicron mailing list attempts resulted in my SMTP IP being blocked by  Google because I had the temerity to send out 20 emails at once. I'll add in rate limiting. I've put the code on github https://github.com/VikOlliver/listomail in case anyone who knows anything about writing mailing lists wants a laugh.

My time has, however, been limited for medical reasons which have left me a tad fuzzy-headed. These got even more fun when combined with floods that've cut off a lot of the local area (including the hospital) and me suddenly finding out that I'm quite allergic to a prescribed antibiotic while on the other side of said floodwater. Can breathe easily again and improving.

A couple of days ago the server running the RepRapMicron mail chat server (NOT reprap.org) was turned off permanently. This left me in a bit of a pickle because I run a few mail chat lists. I *thought* I'd just run up the mlmmj Open Source software like in the good old days, but it turns out that me and mlmmj no longer get along. So I have been forced to write one that runs with very limited resources.

"listomail" can vet incoming messages for redistribution now, but the retry-on-fail stuff doesn't work yet, thus the bit that deletes the incoming message when it has been sent doesn't work either. However, I'm getting there.

Sorry about the diversion from hacking physical hardware, folks. Admin stuff needs doing, I need a bit of a break to do it, and other projects are also on the line here.

Your friendly BOFH 

I'm being distracted by doctors again, but have managed to document the latest incarnation of the Touch Probe on Github https://github.com/VikOlliver/RepRapMicron/wiki/Touch-Probe and put the STL file on Printables https://www.printables.com/model/1755519. Enjoy.