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What to do With a 3D Printer: Make a Custom Microscope Adapter

Posted by Alex R English on

I had an old Nikon medical laboratory microscope and really wanted to find a way to take photos through it so I could share what I was seeing with others. After looking around online and discovering that my only likely option was to have one custom made at great expense, I decided to build one.

Here is the microsope:

Nikon Microscope to receive the 3D Printed camera adapter

I started by designing the camera end of the adapter, and built it as a module in OpenSCAD because I felt an EF Mount would have potential for other applications like body caps, pinhole lenses, other adapters, etc. You can find the associated files on Thingiverse here. I designed this by measuring all of the features of the back of an EF lens with a pair of calipers and a protractor.

First draft of EF Mount interface

Once I had the EF module finished, I created a new OpenSCAD project for the adapter, which called the module. Again, I measured the geometries of the eyepiece I was replacing on the microscope and worked it up. For ease of printing I designed it as two parts that would snap together; I don't think I'll ever get the two parts apart. We printed them in different colors so you can see which part is which; for best results, both parts should be printed in black. You can find the models here.

Assembled microscope adapter made from two press-fit pieces

Bottom view of the 3D Printed microscope camera adapter

The finished adapter is just a hair loose in the microscope, but works without issue.

Canon Camera mounted on Nikon Microscope

Here are some photos of a magnified printed card taken through the microscope:

Photo of paper with pigment through 3D Printed Microscope Adapter

Second View of paper with pigment through 3D Printed Microscope Adapter

Third photo of paper with pigment through 3D Printed Microscope Adapter

After getting everything set up and tested, I wanted to try the microscope out for its intended purpose: printed trace analysis.

I set up the MakerGear Mosaic with a slide attached (with the longer dimension in the X axis) to the print bed by means of polyimide tape at the ends. I manually positioned each axis so the nozzle was centered at one end of the slide (the end closest to X0/Xmin), at about the height I would normally use for a first layer. After heating the nozzle, purging it, and repositioning it, I sent the following gcode to the printer:

G92 X0 Y0 Z0 ; This tells it to set the current position as home, so we can use positions relative to this point
G1 F480 ; Set the feedrate to 480 mm/second
G1 X55 E42.307692 ; Move to 55mm on the X axis while extruding 42.307692 mm of filament.
G1 Z10 ; Raise the nozzle by 10mm now that the trace is drawn

This draws a straight trace 55mm long down the middle of the slide.

Many thanks to the reprap wiki gcode reference.

We still have much work to do, so I'll save the analysis for another post. Through future tests like this and their analysis at the microscopic level, we hope to learn more about nozzles, trace geometry, and calibration. In the mean time, here are some pictures to give you an idea of what we can see.

While the trace looks smooth to the naked eye, you can see ripples here, which I believe to be an artifact of the microstepping of the stepper motors.

3D Printed Plastic Trace on a Microscope Slide

Here is a section of trace with some bubbles in it - this filament has been out for a while and has absorbed moisture from the air.

3D Printed Plastic Trace on a Microscope Slide - note the bubbles (presumably from moisture)

A close up of the bubbles at 220% more magnification. The ripples seen below them in the previous photo aren't as prominent here because of the narrower depth of field.

Larger view of bubbles in 3D Printed Plastic Trace on Microscope Slide

A close up of the bubbles at 220% more magnification. The ripples seen below them in the previous photo aren't as prominent here because of the narrower depth of field.

Microscope view of smear at the start of a 3D Printed Plastic Trace on a Microscope Slide

Also, since the camera can also record video, here is a video panning over the entire trace. Please forgive the shakiness of the pan, it's difficult to move the slide smoothly.

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