Generic Robotic Arm Industrial 3D model is available on CGTrader for $39. Original author: Polygate. Specs: 50446 polys, 51433 verts.
OBJ (OBJ, filesize: 1.42 MB), 3DS (3D Studio, filesize: 836 KB), MAX (Autodesk 3ds Max, filesize: 6.21 MB), FBX (Autodesk FBX, filesize: 2.54 MB), MA (Autodesk Maya, filesize: 2.04 MB), C4D (Cinema 4D, filesize: 1.38 MB)