DeLand Crayon Company: An application of the traveling salesman problem to production scheduling with sequence-dependent setup times

Abstract

NP-complete problems such as the traveling salesman problem (TSP) play a prominent role in most advanced undergrad/graduate courses in discrete optimization modeling. Teaching such an important topic from a purely mathematical perspective without discussing specific applications may result in reduced student interest and motivation. The DeLand Crayon Company case introduces students to an application of the TSP to a practical production-planning scenario with realistic data. In crayon production, proper sequencing of colors in production can result in significant savings in total production time. The primary objective of the case is to provide students with hands-on experience in applying the TSP model. The case requires the students to consider variations of the basic model with the goal of encouraging them to think logically through the process of mathematical modeling and to consider the decision-making implications of their models. This case study can be used in undergraduate- and graduate-level courses in linear/integer programming or in production planning. It was implemented as part of a term project in a graduate operations research course with overwhelmingly positive feedback.