In this thesis, we consider a capacity allocation problem in flexible manufacturing systems. We assume limited time and tool magazine capacities on the Computer Numerically Controlled (CNC) machines. We have a set of operations that have to be assigned to the machines and each operation requires a set of tools to be processed. Our problem is to allocate the available capacity of the CNC machines to operations and their required tools. We consider two problems in this study: maximizing the total weight of operations where there are a limited number of tools of each type available and maximizing total weight minus total tooling cost where the tools can be used or purchased at a cost. We model the problems as Integer Linear Programs and show that they are NP-hard in the strong sense. For the total weight problem, we propose upper bounds, branch and bound algorithm for exact solutions and several heuristics for approximate solutions. For the bicriteria problem, we use Lagrangean relaxation technique to obtain lower and upper bounds. Our computational results have revealed that all solution approaches give satisfactory results in reasonable times.

Thesis--Auburn University, 2006. / Abstract. Vita.

Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 97-114).

Includes bibliographical references (p. 64-71).

The loading problem in a Flexible Manufacturing System (FMS) lies in the allocation of operations and associated cutting tools to machines for a given set of parts subject to capacity constraints. This dissertation proposes a hierarchical approach to the machine loading problem when the workload and tool magazine capacity of each machine are restrained. This hierarchical approach reduces the maximum workload of the machines by partially grouping them. This research deals with situations where different groups of machines performing the same operation require different processing times and this problem is formulated as an integer linear problem. This work proposes a solution that is comprised of two phases. In the first phase (Phase I), demand is divided into batches and then operations are allocated to groups of machines by using a heuristic constrained by the workload and tool magazine capacity of each group. The processing time of the operation is different for each machine group, which is composed of the same identical machines; however, these machines can perform different sets of operations if tooled differently. Each machine and each group of machines has a limited time for completing an operation. Operations are allocated to groups based on their respective workload limits. In the second phase (Phase II), demand is divided into batches again and operations are assigned to machines based on their workload and tool magazine capacity defined by Longest Processing Time (LPT) and Multifit algorithms. In Phase II, like Phase I, partial grouping is more effective in balancing the workload than total grouping. In partial grouping, each machine is tooled differently, but they can assist one another in processing each individual operation. Phase I demonstrates the efficiency of allocating operations to each group. Phase II demonstrates the efficiency of allocating operations to each machine within each group. This two-phase solution enhances routing flexibility with the same or a smaller number of machines through partial grouping rather than through total grouping. This partial grouping provides a balanced solution for problems involving a large number of machines. Performance of the suggested loading heuristics is tested by means of randomly generated tests.

The continued assimilation of advanced computing and information technologies in the workplace in the midst of rapidly changing socioeconomic conditions has led many corporations to transform their corporate culture and structure. These profound changes are implicating corporate functions such as planning, design, manufacturing, and marketing. A significant form of corporate re-structuring has been in the computer and information technology mediated integration of these functions which is sometimes labeled Computer Integrated Manufacturing (CIM). Fundamental questions are provoked regarding the reshaping of these emerging modes and relations of production. Do these developments represent a departure from traditional Taylorist or Fordist workplace operations and organization? Are these emerging modes of work which generally are interwoven with Japanese inspired quality improvement programs and associated manufacturing methods producing a more human-centered workplace? Do these shifts in corporate re-structuring support the possible unfolding of forms of human-centered workplace democracy? To critically inquire and address the above questions, a case study was conducted involving a large manufacturing firm which has been undergoing a radical re-structuring of all its corporate operations. The case study method involves an analysis of the internal discourse(s) and practice(s) of an emerging manufacturing facility called the Factory of the Future (FOF) in the context of a changing corporate culture mediated by computer and information technologies and changing organizational practices. Many sources of information were appropriated to construct a collage of textual material in order to present FOF's unique genealogy and to provide a detailed description of the emerging phenomenon of CIM. Among these were internal documents, videos, and interviews conducted with factory and office workers. Based on a critical interpretation of the case study findings a number of provisional conclusions were reached and may be summarized as follows: • Certain neo-Taylorist and neo-Fordist modes of production are emerging both in the factory and office as the transformation of the corporation proceeds toward a CIM mode of operation. • More human-centered organizational practices have marked the changing corporate culture although they are at times subject to conflicts and contradictions. • Managerial power has grown in the midst of computer and information mediated systems, even though worker participation and involvement in work related decisions has also been enhanced.

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