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Traditionally process planning, scheduling and due date assignment are treated separately. Some works are done on integrated process planning and scheduling and on scheduling with due-date assignment. However integrating all of these functions is not treated. Since scheduling problems alone belong to NP-hard class problems, integrated problems are even harder to solve. In this study process planning and scheduling and SLK due date assignment are integrated using genetic algorithms and Random search techniques. Earliness, Tardiness and length of due-dates are punished. While earliness and tardiness are punished quadratically, due-date is punished linearly. Three results were compared. One is ordinary solution, another one is random search solution and the third one is genetic algorithm solution. Genetic algorithm solution outperforms the other solutions and Random search solution is the second best and ordinary solution is the worst solution. 1

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Because the alternative process plans have significant contributions to the production efficiency of a manufacturing system, researchers have studied the integration of manufacturing functions, which can be divided into two groups, namely, integrated process planning and scheduling (IPPS) and scheduling with due date assignment (SWDDA). Although IPPS and SWDDA are well-known and solved problems in the literature, there are limited works on integration of process planning, scheduling, and due date assignment (IPPSDDA). In this study, due date assignment function was added to IPPS in a dynamic manufacturing environment. And the studied problem was introduced as dynamic integrated process planning, scheduling, and due date assignment (DIPPSDDA). The objective function of DIPPSDDA is to minimize earliness and tardiness (E/T) and determine due dates for each job. Furthermore, four different pure metaheuristic algorithms which are genetic algorithm (GA), tabu algorithm (TA), simulated annealing (SA), and their hybrid (combination) algorithms GA/SA and GA/TA have been developed to facilitate and optimize DIPPSDDA on the 8 different sized shop floors. The performance comparisons of the algorithms for each shop floor have been given to show the efficiency and effectiveness of the algorithms used. In conclusion, computational results show that the proposed combination algorithms are competitive, give better results than pure metaheuristics, and can effectively generate good solutions for DIPPSDDA problems.

Traditionally process planning, scheduling, and due-date assignment functions are applied sequentially and separately. Since these three functions affect each other and if we don't integrate, then they will become poor input for downstream and overall performance will be poor. In this competitive era, we must be competitive also. Integrating these functions will improve overall performance. In this study, we investigated the benefit of integration. We tested different integration level. First, we looked at unintegrated results and later step by step three functions are integrated and finally, we integrated these two functions with WATC (Weighted Apparent Tardiness Cost) Dispatching. In this study, we observed that as integration level increases the solution becomes better. Integrating due-date assignment or scheduling with process planning improves overall performance and if we integrate WATC dispatching with these two functions then we get the best performance. In addition to integration levels, we also compared the benefit of search techniques, especially genetic (directed) and hybrid (semi-directed) searches. At this study every customer has weight and they are scheduled by considering weights to improve performance value.

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Üretim sektöründe süreç içinde oluşan hatalar zamanında tespit edilemediği takdirde kalite yetersizliğini ortaya çıkaracağından müşteri kayıplarına neden olmaktadır. Üretici tarafında ise gerekli kaliteye sahip olmayan hatalı ürünler için kullanılmış olan kaynaklar israf edilmiş olacak ve dolayısıyla zaman ve para kaybına neden olacaktır. Hataları minimize edebilmek için; hataların tespitlerinin yapılması, sebeplerinin bulunması ve önceliklendirilmelerinin gerçekleştirilmeleri gerekmektedir. Bu amaçla uygulama kolaylığı olan Hata Türleri ve Etkileri Analizi(HTEA) çokça tercih edilen hata tespiti tekniklerindendir. Bu çalışmada, incelenen haddehanede oluşan hata türlerinin ve etkilerinin belirlenmesinde Klasik HTEA yönteminin uygulanmasıyla Risk Öncelik Sayısı (RÖS) değerlerine göre hatalar sıralanmıştır. RÖS değerinin hesabı için "Olasılık", "Şiddet" ve "Saptama" değerleri kullanılmaktadır. Bu üç değer kriter olarak kullanılarak, TOPSİS ve ELECTRE metotları ile de hataların öncelik sıralaması bulunmuştur. TOPSİS ve ELECTRE tekniklerinin uygulanmasında kullanılacak olan kriter ağırlıklarını belirlemede ise DEMATEL metodu tercih edilmiştir. Uygulamalar neticesinde, her üç yöntemde de ilk dört hatanın sıralaması aynı çıkmış, takip eden sıradakilerde farklılıklar olduğu gözlemlenmiştir. Böylece, hatalarının önceliklendirilmesi için üç farklı yöntemin karşılaştırmalı olarak değerlendirilebilmesi sağlanmıştır.