Vibro Tool for Capillaries / Test Tubes

This is a tool for compacting material in capillaries (for powder Xray diffraction), but it can also be used to just shake stuff (e.g. in a test tube). I have only ever seen people use the Mettler Toledo LV3 Vibrospatula for this, which is unfortunately no longer made and expensive/rare on Ebay.
This is my low-cost desktop solution using off-the-shelf components. The vibrating action is high frequency & low amplitude (comparable to an ultrasonic toothbrush). Vibration is adjustable via a trimpot (optional). The tool is designed to run off a rechargeable lithium battery (charging port on the left side of the box), but can be easily adapted to an external power supply. The modular design will accomodate tubes up to 20 mm diameter (only two small parts need reprinting to change diameter, no disassembly required). The shaking action is suspended internally on 4 springs, making the case itself vibration-free.

Hardware:
- 13x  M3x10 cylinder head screws (17x if using optional rubber feet)
- 4x  M3x6 cylinder head screws (to attach battery holder to case)
- 13x  M3 heatset inserts (17x if using optional rubber feet)
- 4x  springs (~40 mm compressed, ~5 mm diameter)
- 1x  18650 Lithium battery
- 1x  100x30 mm micro USB 18650 battery charger (e.g. https://www.aliexpress.com/item/1005002820143807.html)
- 1x  5 V panel mount LED (optional)
- 1x  ON/OFF switch (power switch)
- 1x  momentary switch (trigger switch, optional)
- 1x  250 to 500 Ohm potentiometer (optional)
- small piece of rubber/felt/foam sheet for noise dampening under platform (optional)
- 1x  5 V cylindrical vibration motor (e.g. https://www.aliexpress.com/item/1005007046957277.html)
- some wire & heat shrink
- 4x  M3 rubber feet (optional)

The 18650 battery and charger can easily be replaced by direct power from a panel-mounted barrel jack or USB socket (just drill a hole in the case).

Print files/assembly:
- All provided files are rendered for 12 mm test tubes.
- Files are preoriented for print quality (faces down for textured build plates).
- Straightforward print, all printers/profiles and normal filaments should work (fotos are PETG).
- No supports needed except:
- The custom capillary inset with 3 different angles requires supports on the build plate (I used organic with defaults).
- If you want to replicate the shown two tone color scheme, just print at least the lid and case together and manually change the color at 2 mm height. You can put the other parts on the same plate as well, which will also give you a nice dual-color ring on the dust cover. The other parts are anyway hidden inside the case.
- platform_adapter & testtube_sleeve (optional/cosmetic) are the only parts that need to be reprinted for changing the diameter. Alternatively you could print the provided 5 mm platform_adapter (e.g. for NMR tubes) with 100% infill and drill it to the required diameter.
- vibro_tool_lightguide is an optional part to be placed in the bore below the battery charger board. Print from transparent material (100% infill). The board's charge indicator changes from red to green when fully charged and this part improves visibility (a bit).
- Parameters that can be changed in the OpenSCAD file: tube_diameter, motor_diameter, led_diameter, onoffswitch_diameter, triggerswitch_diameter, trimpot_diameter
- If you don't want to fiddle with the panel mount diameters or don't like the positions, you can instead just print the blank lid and drill.
- The motor is affixed with one M3x10 screw held in place with a heatset insert. It can also be glued in, but then it would be hard to replace if it dies.
- The springs are attached with M3x10 screws + heatset inserts.
- The battery board is screwed directly into the standoffs with M3x6 screws.
- See image for wiring. Make sure the wires don't touch the springs and route them behind the corner posts where possible.
- There are some optional files: a printed 12 mm test tube, the various custom capillary insets, a multicolor variant of the dust cover, a 5 mm adapter and a blank lid.
- The adjustable capillary inset requires another M3 heatset insert, an M3x20 or M3x30 screw and some kind of printed knob (I used https://www.printables.com/model/494255-m3-screw-knob).
- Remove the battery before soldering!