Applied Mechanics and Materials Vols. 110-116

Abstract: Rapid change in customer demand and aggressive business competition in high technology industry has driven the need for greater performance with lower price product under short product life cycle. This stimulates semiconductor manufacturing companies to pay much more attention to their cost control and production built strategy. Bad performance in shop-floor planning results in huge inventory, poor equipment efficiency, and therefore it would jeopardize the company sustainability. Consequently, the main objectives of an effective production planning intelligence are to maximize company benefits, meet customer expectation and improve production efficiency. This paper presents an algorithm of production loading plan that balances cost, meet customer delivery request and optimize production efficiency by considering all important constrained factors in manufacturing environment, namely test cost per hour, throughput rate, machine capacity and utilization, hardware set up matrix and limitation, the number of change-over and customer delivery date. The analysis is done by comparing the performance outcome with the common scheduling rules. The result of this new planning logic solution is proved to increase the effectiveness of the production scheduling plan based on available resources on hand and complex of constraint. It also decreases human interfere causing error in planning procedure.

Abstract: Flexible job shop scheduling is a hard combinatorial optimization problem. This paper introduces a simulation-based Genetic Algorithm approach to solve flexible job shop scheduling problem. Four manufacturing scenarios have been considered to access the performance of a job shop with objective to minimize mean tardiness, mean flow time and makespan. Results show that multiple process plans performs better than single process plan for each job type and if only single process plan is made available, then process plan selected on the basis of minimum production time criterion yields better results than other criterion of randomly selected process plan and minimum number of set-ups. Moreover, embedding restart scheme into regular Genetic Algorithm results improvement in the fitness value.

Abstract: This paper is an attempt to develop capability-based Virtual Cellular Manufacturing (VCM) systems and comparing the performance of such systems with classical Cellular Manufacturing Systems (CMS) in the point of travelling distances by parts. In this paper, VCM systems are formed through solving a multi-objective mathematical model with the goal programming approach focused on the part-machine virtual cell formation problem, which groups parts and machines simultaneously to generate virtual cells. These cells are designed by considering machines capabilities with the aid of Resource Element (RE) approach to define processing requirements of parts and processing capabilities of machines and to take into account the overlapping capabilities among machines and optional machines to process parts.

Abstract: The term “Lean” was the Japanese model and had been associated with the practice of interpreting the value added activities from those that are wasted (“muda” in Japanese) in an organization and its supply chain [1]. Apart from that, lean was also known as the focus on reducing the non value added (NVA) waste which impedes the flow of the product as it is being transformed in the value chain [2]. Lean manufacturing also means producing only to direct customer orders, creating the need for less on-hand inventory [3]. Lean layout is one of the lean manufacturing tools which have been applied in this automotive parts manufacturer. This tool encourages good visibility and management of the manufacturing system [2]. The U-shape design is incorporated in this case study in order to improve the efficiency of production. In this research, the current production layout is studied and the improvements are conducted by using U-shaped layout which replaced the traditional layout (straight line layout). The results are shown through the figures of the new layout design in the production line.

Abstract: In this study, the application of a systematic plant layout planning (SLP) to assist the optimum design of process areas and locations is proposed. The number of machines and space requirement in pulley factory is determined. The operation process chart, flow of material and activity relationship chart have been investigated. The relationships between machines, operation sections and material flow are used to determine the suitable position of each activity. The SLP method has been employed to design the two alternative plant layouts and compare the performances between new layout and present layout in term of material flow. The new plant layout is modified by moving a disassembly and surface finish that significantly decrease the distance of material flow, so it is effective increasing production.

Abstract: The research aim was to determine the course outline and study of relationship between conpetency program and Mold & Die occupation. The research tools used to collect the data were questionnaires and focus groups. The sampling group was chosen by purposive random sampling, which included experts related to the development of personnel in the molding industry. Results for this is that the course competencies are defined by the enterprises themselves to be divided into three levels of personnel: operators, experts and management. Role of performance standards can be devided for operating level out of 6 role include skill drawing mechanical works, mechanical works, material, english in industry, math in industry and safety in industry. An analysis of competency courses, by Delphi technique, found that experts, educational institute representatives, related mold personnel development institute representatives and enterprise representatives agreed both times. The difference was that it was higher for the second time although most medians were at ‘agree-the-most’ level. And average correlation is high. Relationship every competence has significant at .01.

Abstract: As globalization has increased in the past few years, many companies attempts to made appropriate strategic decision to meet with this challenge. The problem under study mainly focuses on minimizing overall make-span but additional objectives such as balancing the assembly line and minimizing the variation of completion time are also considered. Due to the complexity of problem solving procedure by mathematical techniques, this paper presents a new approach of hybrid GA-SA implementation in order to meet the problem objectives. A proposed hybrid GA-SA is executed to overcome the problem complexity and meet the problem objectives. In order to check the efficiency of hybrid search techniques, a comparison is done between the results obtained by hybrid GA-SA and simple GA and the results comparison validates the effectiveness of presented hybrid search techniques.

Abstract: The vehicle routing problem (VRP) under study involves managing a fleet of trucks existing to provide transportation services from a centralized distribution center (DC) to a set of geographically dispersed customers. The problem is motivated by a real problem from one of the large chains of high-end retail stores in Thailand. The objective of this study is to develop a simple and effective algorithm that can help the user manage the fleet in order to reduce the total transportation cost. The developed algorithm is based on the parallel savings algorithm but with a stochastic component that has a capability of escaping the local optima. The stochastic component applied a biased random sampling (BRS) and regret based random sampling (RBRS) to the selection of customers to add to delivery routes. Specifically, the selection probabilities are computed proportionally from the savings value of merging customers. The algorithm generates solutions containing delivery routes and schedules for all trucks in the fleet that satisfy daily store demands under limited truck capacity and delivery time window restrictions. Three measures of performance include the total distance, total travel time, and total cost. Computational test of the algorithm was performed on a set of standard problems, and promising results are obtained.

Abstract: This paper investigates the problem of regulating the output of the Liu chaotic system (2004). Explicitly, we construct state feedback control laws to regulate the Liu chaotic system so as to track constant reference signals. The control laws are derived using the regulator equations of Byrnes and Isidori (1990), who have solved the output regulation of nonlinear control systems using neutrally stable exosystem dynamics. The simulation results are also discussed in detail.

Abstract: In order to deal with the difficulty and complicated process of choosing the best product design scheme from several available ones, with the view of satisfying the demands of the users, a multi-criteria decision-making approach is put forward, which is based on layered ordinal relation analysis and aimed to choose the optimal mechanical product design scheme. The basic ideas and detailed procedure are listed out. On this basis, the feasibility of the method is testified with the evaluation and decision-making of the forging machine main frame design schemes as an example. Such a method makes it convenient to analyze the design schemes of large complicated mechanical products; compared with the analytic hierarchy process, it avoids the limitation of the number of elements and reduces the amount of calculation.