Design and development of an automated stacker for highway products of Nucor Steel Corporation

In this paper, a robotic stacker is designed to enable precise stacking of highway sign posts produced by Nucor Steel Corporation, while complying with the required stacking pattern as well as time constraints. The Nucor Steel Corporation bar mill, located in Marion Ohio, relies heavily on manual work force in its highway products division. A highly manual process introduces many safety hazards as well as inefficiencies and inconsistencies. One hazardous position is the bundling of heavy sign posts, which are manually raked into bundles before being manually banded, and workers are at risk for overuse injuries. Moreover, the sign posts are randomly positioned within a bundle, and hence the disorganized bundle is much larger than an organized stack of the same count. Disorganized bundles also hinder further automation processes downstream the production line, such as banding and powder coating the sign posts. This paper offers a robotic stacker solution utilizing Fanuc robot manipulators, custom-built end-effectors, and programmable logic controller (PLC) integrated with human machine interface (HMI) that will result in smaller and organized stacks as compared with the current disorganized bundles, and the removal of a worker from the hazardous position in the process. Organized stacks will also allow for further downstream automation processes. This research project is to be executed at Michigan Technological University and is sponsored by Nucor Steel Corporation.