LCD 산업에서 편광판 제조 물류 및 유리기판 절단을 위한 수학적 모델 개발

Abstract

This thesis consists of one chapter of logistics problems, and two chapters of cutting problems in LCD industries. Logistics chapter includes Chapter II and cutting chapters include Chapter III and IV. Chapter II addresses a linear programming model (LP) for logistics problems of polarizer manufacturing. Chapter III and IV present mathematical programming models for cutting problems of LCD mother glass production.In Chapter II, polaroid films, or so called Polarizer is an optical device transforming natural light into some form of polarized light. Taking the form of films, it is widely used in thin display equipment such as liquid crystal display (LCD). Polarizer manufacturing industry is under constant competition to lower its price with the continuous price reduction in LCD markets. This chapter is particularly concerned with its logistics problems with a focus on minimizing cost for purchasing cores used in moving films in the process. The core movement for Polarizer logistics is formulated into a linear programming problem by employing an event-based pull approach. Two numerical examples are presented to illustrate the applicability of the proposed model with some remarks. In Chapter III and IV, Cutting problems for the LCD mother glass production are presented. This problem is called a two-dimensional strip packing problem (2SP) where small rectangles (items or glasses) are cut from the large rectangle (strip) and the objective is to minimize the length of the strip.In Chapter III, the 2SP is formulated as an integer programming problem and its parameters are obtained by proposing an enumeration algorithm. Numerical results from an actual LCD manufacturing company are presented to illustrate the applicability of the proposed algorithm with a comparison to models in the literature.In Chapter IV, the main concept for formulating the 2SP is to generate the cutting patterns that can be used to produce items from the strip. This problem is a non-convex mixed integer nonlinear programming (MINLP) problem due to bilinear terms in demand and the objective function. To obtain the global optimal solutions, this problem should be transformed into several linear forms. Numerical examples based on the strip packing problem in the LCD mother glass production are presented for comparing these models with other models.