Robotic Arm made in blender 2.83. Materials work both in Cycles and EVEE renderers. The open and close mechanism is rigged ajusting the scale of the object named Empty.
STL (Stereolithography, filesize: 50.4 MB), OBJ (OBJ, filesize: 77 MB), DAE (Collada, filesize: 91.3 MB), BLEND (Blender, filesize: 54.7 MB)