Delta Stage main body Printing issue

Hi!

I would like to print the Delta stage but I am not familiar with OpenSCAD. I succeed to compile something and I tried to print it but it seems that one part is missing because the structure is really weak and nothing holds the feet together:

Does someone has the STL files?
Or a trick to print the right thing?

I could definitely use some help! :hammer_and_wrench:

Thanks !!

Léa

That is certainly not as it should be!

I have had a go at running the openSCAD files. It depends on a number of other modules from the openflexure microscope, but even putting the full microscope SCAD files in what I think is the correct relative directories, the deltastage does not build properly for me either.

What does it look like for you in OpenSCAD? are there any warnings in the OpenSCAD console when it builds the stage?

I had another go, and it has no complaints about finding modules now, but it also built to the structure that you have.

I’m just running a build on my computer now, will see if it has the same problem!
delta_stage.stl (2.3 MB)
This looks correct to me in a 3D viewer:


Clearly the casing is missing from your print, which is strange! Did you build that yourself from the OpenSCAD files, or did you find an STL somewhere? Could you post your STL as well as that photo?

I did not see any warnings. It looks like the structure built when I compiled everything on OpenSCAD. I thought I need to add something in the code maybe?

Thanks for your help

Thanks a lot for the STL file I now can see the right structure with the 3d printing software.

Here is the STL file I obtained:
delta_rate.stl (1.6 MB)

could it be an issue with the version of OpenSCAD?

You shouldn’t need to - I’m compiling the code from the master branch without any modifications as far as I’m aware.

Having taken another look at the project, I now realise that it uses submodules. This is explained in the readme, but it’s unfortunately easy to miss. If you have “cloned” the project you are probably missing the openflexure microscope files that it depends on. The easiest way to explain this is using the command-line git tools, because you can just switch into your openflexure-delta-stage directory and run the commands described in the [readme])https://gitlab.com/openflexure/openflexure-delta-stage/#printingbuilding-it-yourself). If you’re using a graphical git client, you might need to consult its help pages to figure out how to enable submodules. I’m happy to help there if I can, though it’s probably easier if you have access to the command-line git tools.

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I have not got Git and openSCAD on the same computer ( :face_with_hand_over_mouth:) so I just downloaded the scad files from dellta stage and the microscope, but that clearly missed something necessary that a Git clone would have picked up.

That can be the issue indeed, I am very new in GitHub and it is not the easiest to use. I will try again.

Yes, unfortunately even if you click “download zip” it often misses submodules and “large files”, which is annoying.

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Can someone please upload the other files wich aren´t compiled yet. I wont to build one but i m not a CAD Pro to use the Openscad tool.

Thanks a lot!

I went ahead and uploaded the three main parts of the Delta stage which I am printing myself at the moment. I think there are a few other parts that need to be used from the main open flexure microscope but these are just the three parts specific to the delta body.
base.stl (324.3 KB) delta_stage.stl (2.2 MB) feet.stl (340.0 KB)

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Thanks @devingator. It’s worth pointing out that the STLs are missing in part because this is still something of a work-in-progress, so it’s very much not as well documented as the microscope or block stage. However, I’d be excited to see what you can do with it, once it’s printed!

@r.w.bowman Working on getting the parts printed right now. I just found the openflexure a couple of days ago and it looks amazing. I was thinking about integrating a google coral into the design instead of a Raspberry Pi which has a little more horsepower behind it. The hardware architecture is different though so I am running into some problems since packages like gevent and greenlet arent support on aarch64-linux. So working through those problems right now and I may do a slight rework of the main server code to allow it to run.

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cool - we’ve thought a bit about trying other platforms (Jetson Nano seems promising too) but so far have held off, because the Raspberry Pi does everything we need for now. We’d be very interested to hear how you get on, though! Do you know what the camera options are for the Coral? I suspect that will be the hardest bit to port, as the picamera module is quite Raspberry Pi-specific and we’ve not used other cameras (though the software was designed to make that possible, in principle)

Hi, since there are not much documented builds of the delta stage out there, I just wanted to confirm that mine printed just fine. I had no time to look into the driver firmware etc. yet, so it’s more a mockup at this point. But there were also no assembly issues.

What I am wondering is, if all that material which goes into the surrounding casing is really necessary. It seems like it could still be optimized to bring down the print time.

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Nice build. I am interested that you have put the microscope in this rather than using the microscope build. What is it that you get from the delta that you want to use?

I just want to verify how practical the delta stage already is, especially in having delta mechanics with no endstop-switches and therefore, limited absolute positioning. In terms of applications, I am interested in it to function as a microscope with a more complex illumination setup and finely tuned or at least stable illumination -> camera alignment. But for practical stuff, I use the microscope build right now.

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This is very cool, it’s nice to see someone has replicated the delta stage already, despite the sparse instructions! It’s worth mentioning that an older version of the delta stage was used in OptiJ so it has been used in microscopy applications before, though not by me.

The difference between this and say a delta-bot printer is that our range of motion is fairly small compared to the lever length. That means that we can approximate the kinematics with a constant matrix, so if you call your motors [a, b, c] then you can map:

x -> [-cos(30), cos(30), 0]
y -> [cos(60), cos(60), -1]
z -> [1,1,1]

It won’t be perfectly linear, but the deviation from linearity shouldn’t be much worse than the out-of-plane motion in the microscope, provided the mechanism bends only at the flexure hinges (which is a decent if not perfect approximation).

There was a design for microswitches in the feet, done by a previous masters student in Cambridge, which will be lurking in the repository somewhere! That could be fruitfully repurposed for this, I think - though if you build an inverted microscope around it I guess you’d want to have the endstops at the top rather than the bottom, so you can home it without crashing into the sample…

I have also experienced this issue, even when using --recurse submodules. The openflexure-microscope folder is full after cloning but still the outside casing doesn’t render. I’ll raise an issue.