A 3d printed CNC microscope


At what point is it possible to reduce the cost of a microscope without losing image quality?

On this page I’ll try to provide a possible answer, by presenting this experimental project.

This is:

  • A 3d printed microscope
  • Mounted on a 3d printer
  • With computer numerical control to scan chips or even full wafers

Open Hardware

This CNC microscope is based on two open hardware projects:

The microscope is mounted on the Ender 3 using this quick tool change system by ProperPrinting.

Demonstration

Here is a panorama made of 4x4 tiles.
Each tile is made of 14 captures with focus stacking.
It took less than 5 minutes to capture.


GPL169256A (4.7 x 4.3 mm) - click to zoom.



The microscope in action.


Optics

The objective used is a basic biological 4x objective recovered from a second hand microscope I got for 25€, also with 10x and 40x objectives.


4x/0.1 160/-


I tried different cheap 4x and 5x biological objectives from various microscopes, and all gave good results.

The next step is to try with higher magnifications, and I already expect several problems:

Limitations

As expected, this type of 3d printer is not ideal for this purpose.
Especially because of the Z axis.

When moving on the Z axis, some horizontal and vertical drift can be observed and must be corrected before performing focus stacking. This adds a layer of complexity compared to my Olympus BH2 setup. But nothing that can’t be fixed in software.

You also have to keep the Z motor working to not lose the focus (because of the lead screw).

Another problem is the stock motherboard of the old Ender 3.
You need silent drivers with microstepping like the TMC2208 to control the microscope. This can easily be fixed by using an external controller but also adds an extra cost.

Making your own

PUMA Holder

To mount your own puma on this tool change system you will need two files I designed for this purpose:

Note: you have to increase the hole size for the M3 screws on the infinity adapter to be able to slide the screw in. Also, ideally, you want to use a thread taper tool to make a nice M3 thread on the PUMA_Holder.

Electronics

I’m using the same controller as in this article.

You just have to unplug the motors and connect them to the new board.

Some price estimates

3d printed parts are cheap and will be ignored.

In this project, the most expensive parts are:

  • The camera, a SwiftCam SC300 I got for 130€
  • The electronics (Arduino Mega / RAMPS / TMC2208 drivers),
    expect something like 30-40€
  • The objectives, recovered from a second hand microscope (25€)
  • Lenses for the illuminator (10€)
  • The half mirror (5€)

In the end, the microscope itself is by far the cheapest part.

I’m not counting the 3d printer because you need it to print the microscope anyway. I got this Ender 3 used for 70€.

You can replace the camera by something less expensive, like a raspberry pi HQ camera, but I haven’t tried.

Conclusion

In short, what can we conclude from this?

It is worth it to 3d print a microscope?

As you can imagine, there’s no simple answer.
It depends on what you want to achieve.

In my case, I wanted the ability to scan full wafers, because I can’t on my Olympus BH2. I already own a 3d printer, and the electronics. So for me this is a very cheap and interesting solution.

If you’re just starting out microscopy to observie chips (without motorization) and don’t have a lof of money, I think it’s worth it.

You can print the original base of the PUMA microscope, and replace the camera by your smartphone or just by an eyepiece and overral the cost will be low (something like 50€ - 100€).

You will also learn a lot. But printing a PUMA microscope requires a lot of time. It’s made of a lot of parts and it’s not easy to make.