Seven-Axis Welding Robots
Automating most welding applications with an industrial robot can be accomplished with six degrees of freedom, which is why most welding robots have six axes. However, there are some scenarios in which a seven-axis robot is more beneficial for welding automation especially if torch access, peripheral interference, and lack of floorspace are hindering the optimization of your welding process.
Seven-axis robots are considered to be high-DOF (degree of freedom) robots as they are configured with an extra axis. There are two structures for seven-axis robots; articulated robots with an extra axis in their arm or robot transfer units (RTUs). RTUs consist of a six-axis robot mounted onto a track system. The track system is considered the seventh axis of the robot and is usually best for automating applications with large work envelopes. Mounting the FANUC Arcmate 120ic to a track system converts it from a six-axis to a seven-axis system.
Most seven-axis robots are used to automate material handling applications, however, the extra axis has been proven quite useful for welding automation. Some robotic manufacturers have discovered the benefits of seven-axis welding robots and have started manufacturing such models. The Motoman VA100 is a seven-axis arc welding robot form Yaskawa Motoman. FANUC’s seven-axis R-1000ia/120F-7B can be deployed for spot welding automation. There are several benefits to automating a welding process with a seven-axis robot. Some of the key ones include:
- • Eliminates the need for a positioner - Seven-axis welding robots are ideal for applications in which workpieces need repositioning as in most cases the robot can maneuver around parts on its own. This helps to streamline welding packages by eliminating the need for a robotic positioner.
- • Better torch placement - Having an extra axis allows for better torch placement and workpiece access, especially for more complex parts. The extra degree of freedom provides an enhanced range of motion which can allow for better maneuverability around parts for better torch placement.
- • Avoids interference with peripherals - One of the main advantages of a seven-axis robot is its ability to avoid surrounding peripherals, preventing any interference during welding. The VA1400 can bend its arm around obstacles and continue to weld, while the Motoman MA1400 would need repositioning to avoid collision.
- • Stabilizes torch placement - When a seven-axis robot moves its arm to get around workpieces or obstacles, it can do so without moving its EOAT. This allows for stable torch placement, eliminating adjustments that can cause inconsistencies in welds.
- • Improves weld quality - Since seven-axis robots are able to avoid interference with peripherals, improve torch positioning, and provide torch stability, weld quality will be significantly improved, and welds will overall be more consistent.
- • Saves floorspace - Those with a limited amount of floorspace to spare can benefit from automating with a seven-axis robot. Seven-axis robots save space by eliminating excess equipment such as positioners for a more streamlined welding setup.
- • Allows for welding of larger workpieces - If your welding process involves working with large workpieces, then you can benefit from an RTU seven-axis configuration. RTUs provide an enhanced work envelope making the welding of large parts possible.