Browsing by Subject "Manufacture"
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Item Open Access Concurrent consideration of product design, process planning and production planning activities(1998) Adil, Gajendra KumarIn manufacturing engineering, product design, process planning and production planning activities are often considered independently. However, in order to effectively respond to changes in business situations, such as changes in demand forecast, product mix and technology, it is desirable to consider them concurrently. For this purpose, a large-scale linear programming model has been developed. The model considers minimization of the sum of processing cost, late shipment cost and inventory holding cost as the objective, and concurrently selects product designs, and generates process plans and production plans. The number of columns in the formulation can be large and, hence, an efficient column generation scheme is developed to solve the model. The model and solution procedure are illustrated with examples.Item Open Access Effect of load, processing time and due date variation on the effectiveness of scheduling rules(Taylor & Francis, 2002) Lejmi, T.; Sabuncuoğlu, İ.In real manufacturing environments, variations in production factors (i.e. pro- cessing time, demand, due-dates) are inevitable facts. All these dynamic changes, together with random disturbances (e.g. machine breakdowns) can seriously a ect the system performance. In this paper we focus on load, processing time and due date variation and analyse their impacts on a scheduling system. Speci®cally, we investigate the impact of variation on dispatching policies in a job shop environ- ment via simulation. The statistical analysis of the results leads to two major conclusions: ®rst, the relative performance of rules is not threatened much by PV (processing time variation), LV (load variation) or DDV (due date variation) Ð a result that can be a consolation for practitioners in the ®eld. Secondly, the performance of the rules deteriorates, in particular at high levels of PV, LV and DDV Ð a result that can provide new insights into the problem and produces useful information for researchers in their continuous e ort to develop better dispatching rules.Item Open Access Fabrication of polymer micro needles for transdermal drug delivery system using DLP based projection stereo-lithography(Elsevier, 2016) Ali, Z.; Türeyen, E. Buğra; Karpat, Yiğit; Çakmakcı, MelihFabrication of micro needles, which reduce pain during insertion and lessen tissue injury, has recently attracted great interest. Different manufacturing systems have been utilized for the advancement of micro needles such as two-photon photo polymerization, bulk lithography, droplet-borne air blowing and injection molding [1]. This paper proposes a micro fabrication process for polymer micro needles, using DLP based projection-based stereo lithography that is capable of fabricating micro-needles using biocompatible polymers. The fabrication in the experimental setup is performed with continuous movement of the platform in the vertical direction hence good surface quality is obtained. The influence of polymerization time, light intensity of DLP projector and chemical composition of the resins on the production speed and the geometrical accuracy of the micro needles have been studied. The length and the tip diameter of the micro needle are shown to be controlled through these factors. The length and tip diameter of the fabricated micro needles were observed using SEM and optical microscope and measured to be around 520 μm and 40 μm, respectively. The results indicate that polymer micro needles with appropriate geometry can be fabricated using this technique. © 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.Item Open Access A hierarchical model for the cell loading problem of cellular manufacturing systems(Taylor & Francis, 1998) Aktürk, M. S.; Wilson, G. R.A hierarchical cell loading approach is proposed to solve the production planning problem in cellular manufacturing systems. Our aim is to minimize the variable cost of production subject to production and inventory balance constraints for families and items, and capacity feasibility constraints for group technology cells and resources over the planning horizon. The computational results indicated that the proposed algorithm was very efficient in finding an optimum solution for a set of randomly generated problems.Item Open Access An integrated evaluation of facility location, capacity acquisition, and technology selection for designing global manufacturing strategies(Elsevier BV, 1992) Verter, Vedat; Dincer, Mehmet CemalEmergence of global markets enhanced the emergence of global firms which have plants in different countries and implement an integrated management style. Due to the intensive competition in global markets, manufacturing performance is conceived as an important strategic weapon. Facility location, capacity acquisition and technology selection decisions constitute means to implement manufacturing strategies. We review the literature in order to contribute to a better understanding of global manufacturing strategies. As a result we observe that an integrated analysis of the location, capacity and technology decisions is vital for the design of effective global manufacturing strategies.Item Open Access Job shop scheduling with beam search(Elsevier Science B.V., Amsterdam, Netherlands, 1999) Sabuncuoglu I.; Bayiz, M.Beam Search is a heuristic method for solving optimization problems. It is an adaptation of the branch and bound method in which only some nodes are evaluated in the search tree. At any level, only the promising nodes are kept for further branching and remaining nodes are pruned off permanently. In this paper, we develop a beam search based scheduling algorithm for the job shop problem. Both the makespan and mean tardiness are used as the performance measures. The proposed algorithm is also compared with other well known search methods and dispatching rules for a wide variety of problems. The results indicate that the beam search technique is a very competitive and promising tool which deserves further research in the scheduling literature.Item Open Access A multi-family dynamic lot sizing problem with coordinated replenishments: a heuristic procedure(Taylor & Francis, 1993) Mercan, H. M.; Erenguc, S. S.Consider a manufacturing environment where multiple items are produced. These products are grouped into families due to their similarities in design and manufacturing. It pays off to coordinate the manufacture of products in a given family because preparing the facility for producing a family of products involves a major family setup. In addition each individual product in a given family may require a relatively minor setup. The objective is to determine the product lot sizes, over a finite planning horizon, that will minimize the total relevant cost, subject to demand and capacity constraints. In this paper we present an effective heuristic procedure for this problem. Computational results for the heuristic procedure are also reported. Our computational experience leads us to conclude that the heuristic procedure may be of considerable value as a decision making aid to production planners in a real-world setting.Item Open Access Resource recovery management using inventory models and supply contracts: An application to leaded waste recovery(International Society for Environmental Information Sciences, 2005) Gunalay, Y.; Yeomans J.S.Several recent studies have shown that significant quantities of leaded wastes recovered from the disposal of television cathode ray tubes (CRTs) will be entering the waste stream over the next 50 years in a form that is ideal for post-consumer remanufacturing. Furthermore, numerous countries have recently enacted legislation requiring industrial systems to engage in the practice of industrial ecology by having all discarded, returned, or otherwise spent products from manufacturing processes become raw material inputs in subsequent manufacturing operations. Therefore legislation banning CRT disposal together with mandated remanufacturing requirements could lead to numerous potentially attractive business ventures for reprocessing and recycling the high lead content found in this waste. This paper examines inventory issues related to the effective management of these leaded CRT wastes and the nature of the waste flows is considered from the perspective of different management options for inventory control through the use of supply contracts. An effective inventory management policy is extremely important when there is great uncertainty and variability in the year-to-year or within-year quantity of product available - as is the case with the supply of CRT wastes. If it is anticipated that a high percentage of the waste stream will be utilized, then an effective inventory policy proves absolutely essential - but also proves to be an extremely complex process. Consequently, the supply contract approach can be employed to reconcile different pricing preferences with the varying delivery time horizons of different customers. © 2005 ISEIS - International Society for Environmental Information Sciences .Item Open Access Revisitation of the simulation methodologies and applications in manufacturing(2011) Ramanan, R.; Sabuncuoğlu, İhsanManufacturing is one of the largest application areas of simulation. For the purpose of understanding where, how and why the simulation is used in the manufacturing, this survey classifies the manufacturing system into two broad areas viz. manufacturing system design and manufacturing system operations. The two broad areas are further subdivided for this study. The survey discusses the evolution of the subdivisions before detailing the need of simulation in each of the sub divisions of the manufacturing systems. Finally, a discussion is made in order to understand where the research is heading for and identifying the future directions.