Industrial Robot Work Envelope
An industrial robot’s work envelope is the entire area of space that can be reached by some point at the end of the robot arm. Typically, this point is the center of the end-effector mounting plate of the robot arm and does not factor in the addition of tooling to the robot wrist. In other words, it is the range of movement reached by the robot manipulator.
Work envelopes are often referenced as shapes that are defined by a robot’s ability to move its arm vertically, horizontally, and backwards. Work envelopes can be cubic, rectangular, cylindrical, polar, and revolute, among others. The shape or volume of space of a work envelope varies by robot type, reach, and number of axes. A robot’s reach will determine the span of a robot’s arm movements. While the number of axes a robot has defines the range of motion of the robot with each axis determining an independent motion. The more axes a robot has the more range of motion it will have, which is why 6-axis robots tend to be more common for manufacturing. However, there may be areas within a robot’s defined workspace that cannot be reached by its arm. These unreachable areas are referred to as dead zones.
Why are Work Envelopes Important?A robot’s work envelope is important because it defines the area in which a robot will be able to operate in. Industrial robots are unable to operate outside of their work envelope. It is especially important when selecting an industrial robot to have a clear definition of the workspace needed for your application. You want to select a robot that will be able to cover the work area required. If your application involves the handling of a large part, then the FANUC M-710ic/20L would be an ideal option with its wider work envelope, so long as the payload is adequate. Choosing a FANUC M20ia would hinder the success of the application, since its shorter reach makes for a more compact work area.
Expanding Work EnvelopesFor those with applications requiring working with extremely large parts or covering greater distances there are some options for expanding work envelope capacities. Many industrial robots can be integrated with a rail system to be able to work with large workpieces or large spaces. Many applications can benefit from robots with tracks as they expand work envelopes. A ABB 6640 integrated on a track is able to transfer parts from one side of a factory to the other within just a few minutes.
Another option for those needing larger work envelopes would be to consider a gantry robot. These overhead rail mounted systems provide a large rectangular or cubic work envelope that allows the robot to travel across a horizontal plane quickly.
Another option for applications requiring a larger scope for a work envelope would be to opt for an extended reach robot model. Many robot manufacturers offer extended reach versions of their standard robots. For instance, the FANUC R-2000ib/125L is the extended reach variant of the R2000ib/165F. An extended reach robot can provide the additional reach needed for applications requiring wider work envelopes, but not to the extent that a track or gantry system would be needed.