My stacking setup - feedback welcome!

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kaleun96
Posts: 193
Joined: Sat Oct 20, 2018 3:47 pm
Location: Stockholm, Sweden

My stacking setup - feedback welcome!

Post by kaleun96 »

I believe I've posted some version of this setup with a focus on the Arduino controller a few months ago but I've made quite a few changes since then.

The big changes are mostly to do with the electronics, I switched from DRV8825 drivers to the Trinamic TMC2130 and thus was able to remove my limit switches and rely on StallGuard from the driver. If anyone wants to see a video of it in operation and the user interface I can put something together.

Since moving to a bellows I've improved a lot of my earlier stability issues. The main problems plaguing me at the moment are to do with lighting, but I will get to that later. Apart from that, I have no issues working up to 10x at 1.25μm step sizes. I haven't tried magnifications higher, or step sizes smaller, than this yet.


Image

Image

Sunwayfoto macro rail mounted to a Thorlabs construction rail, sitting on top of a Proxxon XY table. Basically my original stacking setup is now my specimen X, Y and Z stages.
This is all sitting on a Newport dovetail rail. So I have a lot of freedom of movement in X and Z stages as I can move the Proxxon tables up and down the dovetail rail and the Sunwayfoto macro rail up and down the Thorlabs construction rail.
Image

The off-axis load spring essentially removed the problem I had with the linear actuator stage jerking to the left or right when changing direction. I don't believe it would be called backlash, just a jerk laterally due to some property of the ball screw.
Not sure if mounting the ball screw at the far end (it's currently floating, unlike the guide rails) would've helped.
You can also see a bracket mounting the bellows to the main structure, this helps when using heavy lenses that cause the bellows to dip forward slightly due to the single mounting point.
The bracket is mounted to a 15mm rod clamp so if I need to move the bellows forward/back I just unclamp from the rails and then clamp them after adjusting the bellows.
Image

You can see I've tacked on an extra 150x150mm breadboard as I was running out of room. I regret not originally buying 150x600 or 300x450 breadboard.
The Newport breadboards are not great for connecting together as they have their counterbored holes at the corners in the place of regular threaded holes.
I believe Thorlabs have their counterbored holes separate to the grid of threaded holes so it's much easier to join adjacent breadboards.
Image

I'm running out of room on this 150mm wide breadboard so I reverted to this odd 15mm rail vertical setup to mount my flash and secondary clamp (for holding up backgrounds, diffusers, etc).
It's nice to have the flexibility of the magic arms as well as being able to position the flash vertically.
Image

I've been putting together this flash diffuser the past few days. I'm still not happy with it though. It has a Profoto dome diffuser mounted concavely, partly held in by a friction fit and partly by magnets.

Using a 45 degree elbow in the diffuser was perhaps a bad idea. The flash tends to only want to bounce out of the top half of the dome since there was nothing forcing it to bounce down after the bend and into the bottom parts of the dome.

This prismatic acrylic mounted at 45 degrees (leaning towards the flash) has helped get the flash to bounce down equally to all parts of the dome. That being said, this setup hasn't improved diffusion much beyond the supplied diffuser from Godox.
I have some Lee diffusion gels in the mail.
ImageImage

I'm also working on motorising the Y and Z axis for the specimen. Just waiting on a few more parts, most importantly the YZ linear actuator setup from Aliexpress.
After careful studying it looked very similar to what is sold at OpenBuilds at about double the cost and since I don't need it to be super accurate or repeatable it didn't make sense for me to invest in some expensive linear actuators for this.

First time using V-Rail for me but I've been impressed so far. I was/am worried about the stability of the 60mm vertical V-Rail that mounts to the linear actuators but it is surprisingly solid. It's attached to the base plate by just for 90 degree corner brackets.
Image


I should mention the wires going to the flash. They're for a light sensor that is placed over the LED indicator on my Godox flash.
When the LED is red, the light detector picks up the signal and tells my Arduino controller that the flash has recycled and is ready for the next photo.
I had to come up with a weird little contraption that would allow me to position the sensor over the LEDs but also allow me to remove it for when I use the flash in the field.
Image

nanometer
Posts: 317
Joined: Sat Apr 30, 2016 10:14 pm
Location: Tucson, AZ

Post by nanometer »

Quite an impressive setup. I would just mount two flashes closer to where the subject is to make it easier to work with diffuser domes around the subject or whatever else you decide. Or maybe just put a larger softbox on a flash, but the PVC piping you currently have is a neat idea.

Do you have an idea of the smallest reliable step size on the V-block slider?

That's a lot of automation! Even detecting when the flash is ready--pretty cool.

kaleun96
Posts: 193
Joined: Sat Oct 20, 2018 3:47 pm
Location: Stockholm, Sweden

Post by kaleun96 »

nanometer wrote:Quite an impressive setup. I would just mount two flashes closer to where the subject is to make it easier to work with diffuser domes around the subject or whatever else you decide. Or maybe just put a larger softbox on a flash, but the PVC piping you currently have is a neat idea.

Do you have an idea of the smallest reliable step size on the V-block slider?

That's a lot of automation! Even detecting when the flash is ready--pretty cool.
Thanks! I happen to have a second flash on the way too. I think you're quite right that it will help my lighting predicaments. When the second flash arrives I might have to do away with the PVC since it's been harder for me to find these parts locally since I moved to Sweden. Then the soft box or dome over the subject is likely the way I'll go as you suggest.

Don't know about the smallest reliable step on the V-Rail sliders. I think they're 2mm pitch but with the Trinamic TMC drivers even if they're up near 4-5mm pitch I should still be able to get 2-5 micrometre steps depending on the microstep setting with decent speeds. If I was going to do a stack and stitch setup I'd be a bit more concerned about the quality but that could be on the cards for the future!

Forgot to post my code if anyone is interested: https://github.com/camdey/MacroStepper
- Cam

cmagno
Posts: 54
Joined: Mon Oct 08, 2012 3:27 pm
Location: Porto, Portugal

Post by cmagno »

A very elegant and flexible solution.
The detection system for flash availability is very clever solution..

I have long been a big supporter of OpenBuilds solutions for their flexibility and robustness.
I am updating my setup to include vertical usage and so I am particularly aware of all successful implementations.

In your setup, you use some materials that I don't recognize.
Can you please detail the parts I identified in your setup as 1 (the vertical bar), and 2 (the base)?

Image

Best regards,
Carlos Magno

kaleun96
Posts: 193
Joined: Sat Oct 20, 2018 3:47 pm
Location: Stockholm, Sweden

Post by kaleun96 »

cmagno wrote:A very elegant and flexible solution.
The detection system for flash availability is very clever solution..

I have long been a big supporter of OpenBuilds solutions for their flexibility and robustness.
I am updating my setup to include vertical usage and so I am particularly aware of all successful implementations.

In your setup, you use some materials that I don't recognize.
Can you please detail the parts I identified in your setup as 1 (the vertical bar), and 2 (the base)?

Best regards,
Carlos Magno
Thanks Carlos. I'm a believer in OpenBuilds too and had I known about them earlier I may not have gone with the parts you highlighted in the picture. Those are from Thorlabs and thus are a bit more expensive. I'll attach an image of the parts list from my invoice with them. Image

To be fair, it is extremely stable and I think the adapter plates are better made and easier to mount than OpenBuilds parts. My problem with OpenBuilds is that the adapter plates often have weird hole spacing patterns and aren't always bilaterally symmetrical.

So I can recommend the Thorlabs parts, the only thing I'd change is going for a larger dovetail clamp/adapter but they were out of stock when I placed the order.
- Cam

proullard
Posts: 7
Joined: Thu Sep 19, 2019 7:44 pm

Small clip on system

Post by proullard »

Where did you get the small plastic alligator clip that would hold a subject in front of the lens? And does it have a pre-drilled hole in the end of the clip to attach to the articulated arm?

kaleun96
Posts: 193
Joined: Sat Oct 20, 2018 3:47 pm
Location: Stockholm, Sweden

Re: Small clip on system

Post by kaleun96 »

proullard wrote:Where did you get the small plastic alligator clip that would hold a subject in front of the lens? And does it have a pre-drilled hole in the end of the clip to attach to the articulated arm?
https://www.kjell.com/se/produkter/el-v ... art-p39775

It has a metal insert inside the end meant for clamping down on a wire. I removed some of the plastic around it to expose the metal insert. It was a snug fit inside a female 1/4" thread.
- Cam

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