I’ve came up with some ideas for an upright delta stage and would like to gather some opinions before actually starting to design it, to avoid any pitfalls.
Due to the weight of the optical module (if a turret is implemented), the optics module will not sit on the dovetail. I’ve considered using the stand for the field dissection scope to hold the optical module however, whether the friction is sufficient to hold it in place is a concern. A 28BYJ linear slider on Thingiverse: Linear Ball Bearing Stepper Side v2 by 3DPRINTINGWORLD - Thingiverse seems to be an attractive solution even though it is quite slow (15 inches per minute).
The electronic components will be mounted at the back or inside the stand instead of below the base. The addition of limit switches can also be considered. After measurements, it seems like the LED grid can fit below the existing stage, just that a holder has to be designed.
That looks like a project that will be fun. My main thought is that you should not need to have z-motion on the optics, as the Delta Stage moves in three axes. You just need to get it within the right range, with the shoulder of the objective RMS thread mount 45mm above the nominal height of the sample.
Thanks a lot for the feedback. The coarse focus was considered to make oil immersion easier to do as i’m not sure if the vertical translation of the delta stage will give enough room to do things comfortably. Though I do agree that removing the z slide does make things a lot easier to engineer.
Edit: the coarse focus also allows 35mm objectives to be used.
I did not get beyond a few lines of OpenSCAD. Lessons learned so far:
Designing to print is not that easy. The OFM makes it look easy but they have put a lot of thought into that. This is pretty obvious if you start looking at the details but can be easily overlooked otherwise.
E.g. the optics modules are made to be printed objective up. So just dropping it onto the revolver will not print at all or require support and still not print great.
There is very little space between the objective thread and the tube lens. Getting the gab between the upper and lower piece of the revolver in between is not impossible but tricky - especially if you want to avoid support.
Printing bearing races without support works if you just cut out a 45° triangular ring. The result look pretty good. I still have changed my model to use two metal ball bearings on the axis as it feels less experimental for now.
While I have very limited experience with 3D printing I would never ever use a 3D printed linear rails for this. May be with metal rails (extruded aluminium or better) and a threaded rod/ metal screw. As this whole thing is going to be much bigger anyway, I would probably just use a (bigger) flexure with a bigger range of motion. Or allow the revolver to be mounted at different heights.
But as I have not build anything working yet take all of these with a generous amount of salt.
In the design of the microscope the spacing between the objective and the tube lens is a parameter and the camera position is calculated from that. So it can be made bigger for this kind of situation.
I would make the optics module and the turret as separate parts. I think it would be very difficult to get them to print as one.
I’ve long thought the delta stage version deserves a higher profile, which I’ve been gently trying to do of late, and this new concept helps with that.
I also think that in terms of getting less technical people enthused about OFM, this type of turret arrangement looks more familiar to them and their pre-existing ideas of what a microscope ‘should look like’ – so may be more attractive to them.
And, at the risk of going off-topic, I think one of the ways to reduce the barriers to entry for variants like the delta stages would be for the kit resellers to offer kits specifically denoted as for the delta version: individually sourcing all the non-printed parts is a massive turn-off for many people.
Just now the Delta Stage is much more experimental than the Microscope. It is based in the design philosophy of the v6 Microscope. There is a huge amount of work needed to get it up to the current standard of the Microscope both mechanically, and in the instructions. For example there is the recent tread on stripped threads for the sample clips - this is very easy to do as there are no embedded nuts, and it means re-printing and re-assembling the main body. This makes it definitely a configuration for experimenters and makers. Kits of the mechanical parts might make sense, but I think at present it is a design where you will need access to a printer. Even for the mechanical parts it is not clear that this will help when you are likely to need to tinker.
The different geometry giving xyz sample motion is particularly useful in some circumstances, but for general use the separation of sample translation and focus in the cartesian Microscope is more appropriate.
I think the main appeal of the delta stage is that it’s a lot easier to mess with the optics when it’s separate from the stage. Factors such as weight or stability of the optics aren’t as important. Is it possible for people to come up with sort of a shortlist of things to improve for the delta stage. I don’t know scad but I think i’ll be messing around with the models in blender and freecad during my summer holiday (for example, adding nut trap to the stage).
Also, does anyone know if it’s possible to remove the o ring and reuse it?
I think the “pre-existing ideas of what a microscope should look like” doesn’t quite capture it. Metal microscopes have a hand full of different settings and options that can be changed by the pull of a lever or a turn of a knob:
The revolver for different objectives
Focus plane of the illumination
Difference illumination filters
NA of the illumination
Possibly tube filters
Switching from through light to epi-illumination
Add camera to optical path
Sure details differ between microscopes but the build in stuff can often be switched in a second or two. For the OFM basically every microscope has a single setup and needs changing parts for doing anything else. Even changing the optics and illumination module is rather fiddly. Having objective and camera in the same module makes having multiple options even more annoying.
I am not saying OFM should do the same. But there are clearly two different philosophies as play here. In the OFM world you are rather supposed to build a second (fifth, eigth, …) microscope and the collection will still be smaller and cheaper than one of the big metal microscopes with some more exotic features.
May be there is room for a fully featured OFM variant. But it would be a very different thing than the current ones.
I think revolver is one of the main features I’m hoping for. Illumination filters and NA can sorta be done with grid illumination. And i believe through light and epi can both be done without swapping out the optics module (just use the epi module and add a transmission light source).
Some things we are will missing out are abbe and kohler illumination. I can imagine mounting those with a separate stand with the standard/delta stage but not in any upright scopes since the space inside the stage is quite small (so unless someone designs a miniaturised kohler I don’t see how that would work).
As for knobs i think it some buttons/potentiometers would do the trick instead of redesigning a mechanism that allows both manual and motorised motion. However, I think that the appeal of knobs is only obvious when you are looking through an eyepiece as they allow you to adjust without loosing your view of the image. They would be redundant since everything on the OFM will be done on a computer.
