Whether a particular robot-cell was originally programmed manually, or through Off-Line Programming (see “Off-Line Programming with No Touchup”), it is imperative to maintain the positional accuracy of these original robot programs throughout production – despite the many hazards encountered on any plant floor: for example, a sudden tool crash, mere ‘tear and wear’ over time, replacement of a robot component such as a motor, etc.
One could of course use a standard ‘Off-Line’ robot-cell calibration solution – such as the DynaCal™ system (see “Absolute Accuracy Robot-Cell Calibration”) – to correct for these issues. This however would be quite time-consuming; above all, a number of scrap parts would likely be produced before one would even discover the existence of a problem to begin with!
The better approach is to use an ‘In-Line Recovery’ calibration solution, in order to automatically detect and correct as promptly as possible any of the possible changes that are likely to take place throughout the lifespan of a robot-cell. The goal here is not to make the robot, or the robot-cell, per se ‘Absolutely Accurate’ (such as with the DynaCal system), but it is rather to minimize any difference in the robot’s positional performance between the initial time of programming (at the launch of a new production line – no matter the Absolute Accuracy of the robot at that time) and any time later on throughout the production lifespan.
The AutoCal™ and the AccuBeam™ systems are both fully automatic In-Line Recovery Calibration solutions. They include a ‘Quick Check’ function constantly monitoring the robot-cell’s accuracy in between production cycles. If required per the Quick Check, the TCP (x,y,z and orientation) and/or the zero-mastering of the robot joints can be automatically re-calibrated (through direct communication with the robot controller).
Another factor affecting robots over time is ‘temperature’, whether due to fluctuations of the ambient temperature in the robot work area, or due to the robot structure heating up as its motors are running following a still-stand. In those cases, the robot can be ‘Temperature Compensated’: this is required in high-accuracy applications where a repeatability of 0.1mm or less needs to be maintained throughout the production lifespan, such as in robotic In-Line Gauging, ‘Form & Pierce’ of car’s ‘Instrument Panel’, aerospace drilling, etc. The AccuBeam System can also be used for Temperature Compensation of a robot.