INFORM ATION TO USERS This manuscript has been reproduced fromm the icrofilm master. UMI films the text directly from the original orcopy submitted. Thus, some thesis and dissertation copies are in ^ew riter face, while others may be fromany type of computer printer. The quality of this reproduction is dependent upon the quali^ of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and in^roper alignment can adversety afreet reproduction. In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. Oversize materials (e.g., maps, drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand comer and continuing from left to right in equal sections withsmall overlaps. Each original is also photographed in one exposure and is included in reduced form at the back of the book. Photographs included in the original manuscript have been reproduced xerographically in this copy. Higher quality 6" x 9" black and white photographic prints are available anyfor photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order. UMI A Bell & Howell Information Company 300 North Zeeb Road. Ann Arbor. Ml 48106-1346 USA 3l3.'761-4700 80D.'521-0600 An integrated approach to Cost-effective Process Planning and Equipment Selection in cold, warm and hot Forming Dissertation Presented in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in the Graduate School of The Ohio State University By Ravikiran Duggirala, B.E. (Hons.), M.S. The Ohio State University 1995 Dissertation Committee: Approved by Dr. Rajiv Shivpuri Dr. Taylan Altan Rajiv Shivpuri Dr. Kosuke Ishii Advisor Department of Industrial and Systems Engineering ÜMI Number; 9526019 Copyright 1995 by DÜGGIRALA, RAVIKIRAN All rights reserved. OMI Microform 9526019 Copyright 1995, by UMI Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. UMI 300 North Zeeb Road Ann Arbor, MI 48103 Copyright by Ravikiran Duggirala 1995 In Memorium To my beloved and great brother, Shyam (1962-1994) To my Wife, Parents, and Family AN INTEGRATED APPROACH TO COST-EFFECTIVE PROCESS PLANNING AND EQUIPMENT SELECTION IN COLD, WARM AND HOT FORMING By Ravikiran Duggirala, Ph. D. The Ohio State University, 1995 Professor Rajiv Shivpuri, Adviser In response to customer request for forged parts, the supplier needs to determine the cost-effective process and the equipment to meet required quantity, shape and properties ensuring the production of defect-free parts. Experts layout a sequence of forming operations to transform a simple billet to a finished forging. These forming operations can be performed in different temperature regimes such as cold, warm or hot of a given material and on several equipment. The choice and design of the individual forming operations influences the need for intermediate operations such as heat treatment, coating, heating, etc. and the selection of forming equipment. It is extremely difficult and nearly impossible to evaluate all possible combinations of processes and equipment to produce a cost-effective forging, manually. In this dissertation, a cost-effectiveness evaluation model and a solution method has been developed to address the above problem. A discriminating cost model (DCM) has been developed to measure cost-effectiveness, and a iv modified form of 'generate and evaluate' search methodology applied to find cost-effective solutions to produce formed parts. A prototype computer system 'CEPESS' (Cost-Effective Process and Equipment Selection System) has been developed incorporating the developed evaluation model and solution method. The research focussed on steels for materials, presses and headers for forming equipment and processes which are cold, warm and hot combinations of the forming operations: open fonvard extrusion, closed forward extrusion, backward extrusion, upset and dimple. The capabilities of the CEPESS was verified by running different example scenarios. The validation of the system was accomplished by application of CEPESS to the current process of making 'outer races'. Forming trials and experiments were conducted to verify the feasibility and cost-effectiveness of the process and equipment changes recommended by the system. The system has been built using 'ICAD' and 'Lisp' with features to enable sensitivity evaluation. The methodology developed in this research is an element of concurrent engineering where forming process planning and equipment selection have been considered concurrently with costs. The developed methodologies and system can be extended to include machining operations utilized subsequent to forming operations. ACKNOWLEDGEMENTS This dissertation is the culmination of a pursuit which involved the time and efforts of many people, whom I wish to acknowledge. To Dr. Rajiv Shivpuri, my advisor, my sincere appreciation and gratitude for his guidance, counsel and insight. To Dr. Taylan Altan for supporting my work at Ohio State University and the ERG, and being a source of inspiration for new ideas and innovation. I extend my gratitude to Dr. Ishii and Dr. Miller for providing guidance and suggestions. I wish to thank Dr. Aly Badawy, my mentor, who stood beside me in good faith through thick and thin with continued encouragement and guidance. I also thank him and General Motors Corporation for providing me with a fellowship and support to pursue my academic goals. Thanks to Mr. Dave Hitz, my supervisor, for his encouragement and support in completing my work. I thank my colleagues and personnel at work who have provided me with assistance to assimilate knowledge, run experiments, and build software modules. My thanks to Dr. Uday Korde for his valuable suggestions and support. Finally, I wish to thank my wonderful wife, Kalpana, for her unfailing support, love, and endurance throughout this seemingly never-ending pursuit of my dreams. I am grateful to my parents, brothers, parents-in-law, and relatives who also provided inspiration and encouragement throughout this period. vi Unto God, my ultimate gratitude, for his grace and guidance that he has showered on me throughout my life and pray for his continued support. VII VITA September 28th, 1961 .......................... Born - Madras, India 1983 ..................................................... B.E. (Hons.), Mechanical Engineering College of Engineering, Guindy, Madras, India. 1985 ..................................................... M.S. Mechanical Engineering, Ohio University, Athens, Ohio. 1985-present ........................................Senior Process Engineer, Saginaw Division, General Motors Corp. Saginaw, Michigan. FIELDS OF STUDY Major: Industrial and Systems Engineering Manufacturing Engineering, Artificial Intelligence, and Mechanical Metallurgy VIII TABLE OF CONTENTS ABSTRACT.................................................................................................. iv ACKNOWLEDGEMENTS..............................................................................vi VITA.............................................................................................................. vii TABLE OF CONTENTS................................................................................ix LIST OF FIGURES........................................................................................xiv LIST OF TABLES..........................................................................................xviii 1. INTRODUCTION.......................................................................................1 1.1 Global competition in manufacturing ..............................................1 1.2 Overview of forming processes, materials and equipment ..............2 1.3 Organization of the dissertation ......................................................5 2. PROBLEM STATEMENT..........................................................................8 2.1 Need for cost-effective process and equipment selection ...............8 2.2 Problem definition ..........................................................................17 2.3 Research Objective.......................................................................18 2.4 Current approaches to process selection .......................................19 2.4.1 Costing and process selection methods ......................... 19 2.4.2 Limitations of process planning and costing systems in metal forming ........................................................................27 ix 2.5 Approach ............................................................................ 28 2.5.1 Literature review............................................................. 28 2.5.2 Selection of part family ....................................................28 2.5.3 Knowledge acquisition .....................................................29 2.5.4 Develop structure for knowledge ..................................... 30 2.5.5 Develop a cost-effectiveness evaluation method .............30 2.5.6 Develop a computer system ............................................ 31 2.5.7 Generate cost-effective process and equipment selection scenarios .................................................................... 31 2.5.8 Perform forming process