Seven Axis Robots
The number of axes of industrial robots can vary. Six-axis robots are the most common for robotic automation, but other axis configurations such as three-axis, four-axis, and above are also used to automate manufacturing processes. There are some scenarios in which an axis configuration either lower or higher than six may be more advantageous.
Seven-axis robots fall under the category of high-DOF robots since they have more than six axes. Seven-axis robots are gradually being used more as robotic applications become more complex and manufacturers look towards more general purpose robots. There are two configurations for a seven-axis robot. The first consists of an articulated robot structure with an additional axis in the robotic manipulator arm. The extra axis allows the robot to be able to bend its arm to avoid peripheral objects without moving its EOAT and to better access workpieces. The Motoman VA1400 is an example of a seven-axis articulated robot. The second seven-axis configuration is an RTU with a six-axis robot. The track system of an RTU is considered the seventh axis when integrated with a six-axis robot. The seventh axis enables the robot to travel linearly along the track from one side of a factory to the other or in between workstations. Mounting the FANUC M710ic/50 to a track system allows it to automate a sequence of applications due to the mobility provided by the seventh axis.
Applications for Seven-Axis RobotsSeven-axis robots can be used to automate material handling applications. RTUs are especially beneficial for material handling automation as they speed up the transfer of parts in part transfer or pick and place tasks. Integrating the FANUC M-20ia with an RTU allows it transfer parts several feet within seconds. Seven-axis robots can also be beneficial for automated machine tending, machine loading/unloading, and injection molding applications. Seven-axis welding robots are also starting to catch on with both FANUC and Yaskawa Motoman releasing seven-axis articulated robots for welding automation. FANUC’s R-1000ia/120F-7B is one of their latest R-1000 robots and is capable of automating spot welding. The VA1400 from Yaskawa Motoman is specifically designed for arc welding automation with an extra axis.
Benefits of Seven-Axis RobotsAutomating with a seven-axis robot allows for better tooling positioning, especially when working with parts with complex geometries. The extra axis provides greater mobility to maneuver or bend the robotic arm around parts. The extra axis also provides greater tooling stability as the robot can bend its elbow to move around an object without having to move its end-effector. Seven-axis robots may also reduce the peripheral equipment needed to complete your robotic system, helping to save on purchase and integration costs. Since seven-axis robots are able to maneuver around parts, repositioning is avoided and peripheral equipment such as robotic positioners are not needed.
Having an extra robotic axis can also increase the reliability of the robot’s operation by avoiding object interference. Since seven-axis robots have an additional degree of freedom they are able to avoid peripheral objects and collisions better than six-axis robots. Preventing interference from peripherals avoids unnecessary downtime and unexpected stoppages for greater uptime and reliability.