How Many Axes Will Your Robot Require?
When selecting an industrial robot there are a number of factors that are important to consider. One of those factors is the number of axes your robot will need. Industrial robots are designed with various axis configurations. Most industrial robots used in manufacturing have six axes, but they can range from three axes to over seven axes.
An axis, also sometimes referred to as a robot joint, represents a degree of freedom. Each degree of freedom is responsible for an independent motion. Articulated robots with less than six axes are referred to as low-DOF robots while those with seven or more axes are called high-DOF robots.
The number of axes your robot will need will depend upon the type of application you are automating along with the complexity of the process. Low-DOF robots have a more restricted range of motion, which limits the types of applications they can automate. Low-DOF robots are also only capable of automating simple processes since the amount of space they can access is restricted.
Three-axis, four-axis, and five-axis robots all fall under the low-DOF category. Three-axis robots can move along the X, Y, and Z planes but are not capable of rotating or tilting motions. This prevents them from being able to reposition parts. SCARA, cartesian, and some delta robots are available in three-axis configurations. Applications for three-axis robots typically include automated pick and place, part transfer, and robotic machine loading.
Four-axis and five-axis robots tend to be more common in manufacturing than three-axis robots. These robots can consist of SCARA, delta, and articulated robot types. Four-axis robots can operate in the X, Y, and Z planes with the ability to rotate parts with a fourth axis in the robotic wrist. Five-axis robots are capable of the same motions as four-axis robots with the addition of pitch and yaw motions of the end-effector due to a fifth axis in the upper robot manipulator arm. Both of these axis configurations are common for automating palletizing applications. The four-axis Motoman EPL300 features the stability needed for lifting heavy payloads. The FANUC M-410ib/140H is a five-axis palletizing robot.
The more axes a robot has the more movements it will be capable of for access to greater amounts of space. This is why for more complex applications a six-axis or higher axis robot is needed. Six-axis robots feature a full range of motion with the ability to move along the X, Y, and Z planes with the addition of roll, pitch, and yaw motions. Six-axis robots can automate just about any manufacturing application given their large range of movement. This is why six-axis robots tend to be the most common as they provide greater versatility and make excellent general-purpose robots. The FANUC M-20ia is a six-axis robot with multi-application capabilities. The Motoman MA1440 is a six axis robot commonly used in welding automation
With six-axis robots featuring a full range of motion you may be wondering if there is really a need for high-DOF robots. High-DOF robots are a newer concept but their ability to ease complex applications and reduce peripheral equipment is starting to gain attention. Seven-axis robots and other high-DOF robots can ease applications involving parts with complex geometries as they are able to better position tooling and maneuver around peripherals. Their extra axes can also eliminate additional equipment such as robotic positioners, streamlining productions.