An intelligent decision support system for machine tool selection

AN INTELLIGENT DECISION SUPPORT SYSTEM FOR MACHINE TOOL SELECTION

By EMRAH ÇIMREN

Submitted to the Graduate School of Engineering and Natural Sciences In partial fulfillment of the requirements for the degree of Master of Science SABANCI UNIVERSITY July 2004

AN INTELLIGENT DECISION SUPPORT SYSTEM FOR MACHINE TOOL SELECTION

APPROVED BY:

Assistant Prof. Dr. Bülent Çatay (ThesisSupervisor ) Associate Prof. Dr. E rhan Budak (Thesis Supervisor ) Assistant Prof. Dr. Gürdal Ertek Assistant Prof. Dr. Hüsnü Yenigün Assistant Prof. Dr. Kerem Bülbül

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DATE OF APPROVAL:

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ACKNOWLEDGMENTS I would like to express my deepest appreciation to my advisors, Associate Prof. Dr. Erhan Budak andAssistant Prof. Dr. Bülent Çatay, for the guidance, encouragement, and feedback they provided me during the thesis process.

Abstract The selection of appropriate machines and equipments is one of the most critical decisions in the design and development of a successful production environment. Considering the detailed specifications related to the functional requirements, productivity, quality,flexibility, cost, etc., and the number of available alternative machine tools in the market, the selection procedure can be quite complicated and time consuming. In this thesis, a user-friendly decision support system called Intelligent Machine Tool Selection is developed for machine tool selection. The software guides decisionmaker in selecting available machines via effective algorithms: AnalyticHierarchy Process (AHP). It has some special features which may not be included in other decision support systems. The user does not need to have detailed technical knowledge as he is guided by simple questions throughout the selection process. The user first determines the relevant criteria to be considered (such as productivity, flexibility, etc.) and then makes a pair-wise comparison of eachcriterion to the others. There are many sub-criteria such as machine power, spindle speed, tool magazine capacity, etc. which are used to determine the scores for each criterion. If desired, some important requirements for an application, such as power and force, can be determined using process models which are also integrated to the software. The software can store the relevant new inf ormationassociated with the user so that it can be made available to facilitate the successive decision-making processes. After a list of machines with their specifications is retrieved from the database based upon the user specified requirements, the selected criteria are considered in the AHP process. The application of the system is presented through several examples. Furthermore, sensitivity analysis is usedto determine the most critical criterion and the most critical measure of performance. Cost analysis is carried out for the purchasing decision of a selected machine tool and its additional options. Reliability and precision analysis guide decision-maker selection of suitable machines.

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Özet Uygun tezgahlarin seçilmesi verimli bir üretim ortaminin tasarimi ve gelistirilmesinde verilmesigereken önemli kararlardan biridir. Makinelerin fonksiyonel gereklilikleri, üretkenlikleri, kalitesi, esnekliklikleri, maliyeti, pazarda satisa sunulan uygun makine alternatifleri vs. gibi kisitlara bakildiginda makine seçim problemi karmasik ve çözümü için zaman gerektiren bir hal alir. Bu çalismada takim tezgahi seçiminde kullanilan, kullanici uyumlu bir karar destek sistemi gelistirilmistir.Gelistirilen yazilim, Analytic Hierarchy Process (AHP) yöntemini kullanarak, karar vericiye el eki makine alternatifleri arasindan uygun d makineleri seçmesi için yol gösterir. Yazilim diger karar sistemlerinden farkli olarak bazi özelliklere sahiptir. Bunlardan en önemlisi, seçim asamasinin sadece basit sorulardan olusmasi nedeniyle, kullanicinin makine teknik bilgisine sahip olmasa bile karar...