Threaded Mode | Linear Mode

View Profile · 03-13-2012 6:21 PM

(03-13-2012 4:52 PM)Fly So Hi Wrote: Good point, a tip holder near each bottle on the grid.

Yup. I was thinking the only other way would be to somehow integrate the pipette tip into the bottle. While that would be cool, it would be annoying to do, and even if there were pre-made bottles like that, I'd like to not have to use special bottles just for the machine eventually. That tends to be annoying and in general if this is something to be built by others in then future, then we should avoid the need for specific parts which might be unavailable at a later date.

(03-13-2012 4:52 PM)Fly So Hi Wrote:
(03-13-2012 1:40 PM)gentlmentlemen Wrote: I'm thinking the main linear actuator design comes first in importance, then design for interacting with the bottle (raising/lowering said main linear actuator) and expelling the liquid into the mix bottle, then lastly transporting from concentrate to concentrate.

I was thinking the same thing!

Cool! In that case, lets talk linear actuators!

We could probably buy one premade, but we might have to add onto it after that, idk. We would need accuracy relative to the distance which the single volume pipette must travel, and as such the first and most important thing in my mind is to look at how far the button/plunger on the back of pipettes travels for various pipettes, or whether it's all the same.

(03-13-2012 4:52 PM)Fly So Hi Wrote: Enough to cover about a quarter of the grid's surface, i think. Check this video, they can get to 2.5 ÂºF

Woah. That's pretty crazy. Well, giving the bottles a 3" by 3" square each (I doubt we'd need more than that on average, maybe a couple crazy big ones just for fixatives and PA), we'd have a grid from somewhere around 270 to 450 square inches for the whole grid, but I'm shooting pretty large there. Probably wouldn't have to be near so big. I don't like the idea of a lot of different bottle-holder sizes though, I figure we may want some bigger ones for convenience of not changing them out, but with all the concentrates (which will constitute the cast majority of the bottles), we probably would only need something like 1.5" by 1.5" squares even for the largest bottles.

(03-13-2012 4:52 PM)Fly So Hi Wrote: Very likely the empty space. This problem goes away with pipettes/tips.

That's what I figured. I noticed that in the video it was a pretty intensely thick liquid that was beading up there. In contrast, pretty much any normal liquid will have a small bubble you can push out to the end with my syringe.

(03-13-2012 4:52 PM)Fly So Hi Wrote:
(03-13-2012 1:40 PM)gentlmentlemen Wrote: I meant more just whether it would be physically able to reach a place to touch the drop of liquid to.

Now you got me thinking. Very well observerd. Maybe extra pressure for the small ammounts, so it squirts the concentrate. We'll have a problem if it sprays instead of squirts... I'll think of something.

Well let's see how much of a problem it is first. It may turn out that it only is a problem for fixatives, and then we can focus on a more specific solution for those. One solution (for those) might be to use pipette tips with larger openings for the thicker stuff, but maybe that would just make things worse, idk. But I think that as soon as you touch it to another material (including the surface of the liquid in the mix bottle) then the same strong cohesive and adhesive forces keeping it stuck to the tip of the pipette would be combined with gravity, and if you still have room left with the linear actuator, you could throw in it's force of air pressure by depressing it past the "second stop" to the "third stop" so to speak after you've touched the drop to the liquid. Ought to work. The only significant problem I see right now would be dealing with the variance of drop size, but I would think that would primarily be determined by the carrier, and in addition I'm willing to bet that it will either be fine, or it will be a really large drop compared to the accuracy of the machine.

Still, if we have a way to touch the side of the bottle that would be nice, but then it might have to be a different side for every touch needed.

Which brings me back to my earlier point: lets observe what happens first.

(03-13-2012 4:52 PM)Fly So Hi Wrote:
(03-13-2012 1:40 PM)gentlmentlemen Wrote: In both cases, it should be very easy in future designs to add more mix bottles at a time, so that if you're making 2 different mixes at once which both include the same molecule, it doesn't have to rotate the rotary (or go around the track) again for each extra mix bottle. That way it could make 2 mixes in one trip and only make 1 stop per bottle.

I know what you mean, and that's a good idea, i just think we gotta walk before we can run. Let's focus the basics first to keep it simple and practicable.

Agreed. All I meant by that was that if we wind up with a choice between walking on our hands vs walking on our feet, then lets be sure to walk on the ones without opposeable thumbs. If we have to go all frankenstein and piece a thumb onto our foot, so be it, but the ones already built in tend to work better and take less work.

But I'd rather it become a walking freak with weird sewn on thumbs than a cool drawing that can't walk at all of course.

(03-13-2012 4:52 PM)Fly So Hi Wrote: I usually mix the components in this particular order because a more viscous component like DPG evaporates much slower than Alcohol, for example. The moment i add alcohol to DPG, the alcohol is already "fixed", so it will evaporate less, not spoiling the measures.

Ah... makes sense. I was going to mention something about some of the accuracy being ruined by evaporation... very smart indeed.

(03-13-2012 4:52 PM)Fly So Hi Wrote: Here's the drawing i wanted to show you:

Fig. 1 - The light grey part is the top layer.

Fig. 2 - The dark grey cover is the middle layer, between the top layer (grid) and the bottom layer (tube with liquid). It slids back revealling the liquid inside the tube.

Very cool. So just to be clear on it, its basically the same sliding lid idea I had, but individualised for every bottle? That would actually make things a ton easier... no drip problems... and changing out the covers is as easy as changing out the bottles!

(03-13-2012 4:52 PM)Fly So Hi Wrote:
(03-13-2012 1:48 PM)gentlmentlemen Wrote: Also, do you know of any cheap or free CAD type programs we could possibly use to share designs?

I'll google something.

Can't wait! I'll try as well and see what I find. Any way we have of showing each other what we mean and of sharing designs can then later be attached to the posts showing where to get the materials and how to build it, etc.

Threaded Mode \| Linear Mode Sprayers, Scales, and Syringes
Author	Message

Quick Search	[X]

Advanced Search