For decades, many manufacturers have counted on robots to tirelessly produce parts of predictable quality. One of the key attributes of robots is their repeatability, which means that their tool tip will return to the same pre-programmed location with a known and relatively small error. Repeatability plays a role in ensuring predictability so that production stays within quality targets and the downstream processes receive parts meeting the required tolerances. It is critical to note that repeatability is distinct from accuracy. A robot may position its end of arm tool (EOAT) at the same location with minimal errors (repeatability), but that location may not be where it should be (accuracy). Both accuracy and repeatability are key performance characteristics that influence the robot’s ability to meet a manufacturing process’s needs.
Generally, a robot’s repeatability and accuracy are not achieved without upfront preparations and maintenance activities. As robots evolve to become more affordable and useful, a greater number of manufacturers are able to adopt them, including smaller enterprises. In many cases, the new users of robots are faced with having to educate themselves about concepts related to repeatability and accuracy that may seem esoteric. In this article, we discuss some factors for manufacturers to consider and possible tools that may help.