A state-space solution search method for apparel industry spreading and cutting

The spreading of fabric onto cutting tables in several layers, and the cutting of this fabric in the most cost-efficient manner to produce a pre-determined number of garments is the apparel manufacturing phase that precedes assembly (sewing) and finishing. The problem consists of determining the lowest cost spreading and cutting schedule for garments of different styles, colors, and sizes, subject to physical constraints of cutting table length and cutting knife height as well as business constraints of required demand for each stock-keeping unit (SKU). The determination of this optimal spreading and cutting schedule for various garment styles is a difficult combinatorial NP-complete optimization problem. This paper proposes the use of an innovative state-space approach using heuristic rules to solve the problem: it is modeled as a least-cost search in a graph where each node represents a different spreading and cutting schedule. Several solution algorithms and heuristics are proposed and tested and an illustrative application to a Brazilian apparel company is presented.