Multiple part-type scheduling in flexible robotic cells

This thesis considers the scheduling problem arising in two-machine manufacturing cells which repeatedly produce a set of multiple part-types, and where transportation of the parts between the machines is performed by a robot. The cycle time of the cell depends on the robot move sequence as well as the processing times of the parts on the machines. For highly flexible CNC machines, the processing times can be adjusted. As a result, this study tries to find the robot move sequence as well as the processing times of the parts on each machine that minimize the cycle time. The problem of determining the best cycle in a 2- machine cell is first modeled as a travelling salesman problem. Then, an efficient 2-stage heuristic algorithm is constructed and compared with the most common heuristic approach of Longest Processing Time.