SG90S Servo‑Driven Mechanical Gripper

I. Inspiration

Inspired by a compact biomimetic gripping mechanism, this design uses an SG90S micro servo as the power source and employs a central single gear paired with bilateral rack‑and‑pinion transmission. It is suitable for robotic end effectors and STEM‑oriented experimental grasping applications, balancing educational insights into mechanical principles with DIY robot‑modding needs.

II. 3D Printing Parameters

The housing and racks are printed using PLA filament, while the gears can optionally be made from wear‑resistant PETG. The gripper fingers and mounting brackets feature a 0.35 mm assembly clearance, and the contact surfaces are secured with individual screws. Wall thickness is uniformly set at 2 mm, with no large overhanging curved surfaces; only minor local fillets are provided to offer basic structural support.

III. Structure and Assembly

The unit includes a fully enclosed servo housing that protects against impacts and damage. The servo’s output shaft drives a central gear, which in turn synchronously actuates the bilateral racks to open and close the gripper. Anti‑slip grooves on the gripping surfaces enhance friction, and the system can be precisely controlled via microcontroller programming to regulate the opening angle.