Light-Duty Screw Driving Robot - SR375Y-THETA Light-Duty Screw Driving Robots. The robot incorporates a horizontal turning arm, axis, with a Y-axis. THETA and Y axes are powered by AC servo motors, while the screwdriver stroke is powered by a pneumatic cylinder and the spindle rotation is powered by a NITTO driver. The screws will be automatically blowfed by means of our centerboard hopper screwfeeder equipped with a single-shuttle air escapement. Maximum working envelope of the robot is THETA-axis, 150mm; Y-axis 300mm, Z-axis 100mm.