Optimizing the load capacity of a compliant-mechanism-based microplate gripper for biomedical lab automation

Objectives: Laboratory automation enhances repeatability
and throughput in scienti c and industrial applications. An
important aspect of automation is transportation of stan-
dardized components, such as microplates (MPs). Previously,
we developed the compliant-mechanism-based gripper
(“CrocoGrip”), enabling secure and contamination-free MP
transport. However, we have yet to optimize the gripping jaws
to increase the gripper’s maximum load capacity (LC). In this
paper, we optimize the design and surface of CrocoGrip’s jaws
to optimize its LC. CrocoGrip works like a torsion spring, so its
opening width, which de nes the CrocoGrip’s deformation, its
jaw arm length, and the jaw’s surface material a ect its LC.
Methods: We tested the LC of six di erent jaw materials at
di erent opening widths. The best-performing jaw surface
was further evaluated at a second jaw arm length.
Results: Jaws equipped with silicone inserts performed the
best (LC=2.93 N). Aluminum with di erent surface smooth-
ness performed the worst (0.68 N≤LC≤1.56 N). Decreasing
the jaw arm length from 81 mm to 66 mm increased the LC of
the silicone-insert jaws to 3.71 N.
Conclusions: The improved LC allows the safe handling of
MP (weight ≤127 g), enabling the use of the CrocoGrip for a
broader range of tasks.