Robotic applications such waterjet cutting, laser cutting, applying a bead of sealant, arc-welding, etc. are generally ‘path-intensive’, in that such applications require the Robot’s TCP to accurately follow a specific path along a part (located on a fixture), and that such path is often formed by a series of points at a rather close distance from one another (depending on the path’s shape).
Such paths are typically good candidates for Off-Line Programming: the part, and the desired path along it, are typically well-defined in CAD, and the amount of points to program along such path would generally make their manual teaching on the plant floor very time-consuming. The desired robot programs are thus often generated through Simulation, after proper modeling of the robot-cell, and also include the necessary end-effector-related commands (e.g. when to start/stop the flow of sealant).
However, the level of precision typically required at the robot’s TCP for such applications makes it unlikely that the robot programs generated through Simulation will be accurate enough when executed on the robot controller ‘just like that’: Absolute Accuracy robot-cell calibration is required, with the DynaCal™ system (see “Absolute Accuracy Robot-Cell Calibration” and “Off-Line Programming with No Touchup”).
More specifically, the measurement point used for calibration purposes will be located right at the desired TCP, i.e. coinciding with the point of interest on the end-effector (generally some fixed distance away from the nozzle’s end of the waterjet tool, or the sealant tool, etc.): a dedicated tool with the proper dimension will temporarily be affixed to the end-effector. On the other end, the measurement equipment will be referenced to the fixture holding the part.
