Preparing 3D-Printed holders for cuvettes

Important: 3D-printing cuvette holders

At UZH, the cuvette holders are printed with a polyamide printer and then the surface is vibratory finished. Feature sizes depend on how much material is ground away (Usually, 0.1 mm in our conditions). After grinding, throughholes in both the bottom and top holders are drilled with 1 mm drill bit as the smallest feature size of our printer is not sufficiently good. 1 mm holes are adequate for 0.7 mm thread. In addition, the central M4 thread has to be tapped.

Important: Depending on your manufacturing tolerances, the fit can be too tight for a cuvette, leading to breakage. Do test prints and check the fit before manufacturing large numbers of parts.

Necessary parts and tools

• Top & bottom cuvette holders

• M4x8 or M4x6 screw & hex key

• Thorlabs KBT25/M (Top plate of the KB25/M kinematic base)

• 0.7 mm transparent flexible cord (Jewelry Elastic Cord by Griffin, Stretch Magic 200%, clear)

• 10x20 mm sample cuvette

  Overview of all the necessary parts (apart from the sample cuvette).

Preparing the holders

Cut 40 cm of flexible cord off and thread it through two holes in the top part (opposite the diagonal cutouts to lock the cord in place).

Then, push both ends of the cord through the holes in the bottom part.

As a next step, attach a cuvette to the top part and use it to adjust the length of the cord while directing it through the two remaining holes in the top part: As a final step, attach the kinematic top plate with the M4 screw and use it to tighten the cords. Make sure that the cuvette is pressed firmly against the top part. Test whether you can easily remove and reattach the cuvette.

The finished sample holder with a cuvette & sample attached: