In semiconductor manufacturing, automated material handling systems (AMHSs) transport wafers through a complex re-entrant manufacturing process. In some systems, Overhead Hoist Transport (OHT) vehicles move throughout the facility on a ceiling-mounted track system, delivering wafers to machines and storage locations. To improve efficiency in such systems, this thesis proposes an adaptive dynamic routing approach that allows the system to self-regulate, reducing steady-state travel times by 4-6% and avoiding excessive congestion and deadlock. Our approach allows vehicles to be rerouted while in progress in response to changes in the location and severity of congestion as measured by edge traversal time estimates updated via exponential smoothing. Our proposed method is efficient enough to be used in a large system where several routing decisions are made each second. We also consider how the effectiveness of a AMHS layout differs between static and dynamic routing. We demonstrate that dynamic routing significantly reduces sensitivity to shortcut placement and allows an eight-fold increase in the number of shortcuts along the center loop. This reduces travel times by an additional 24%. To demonstrate the effectiveness of our proposed routing approach, we use a high-fidelity simulation of vehicle movement. To test the impact of routing methods on layout effectiveness, we developed an associated Excel-based automated layout generation tool that allows the efficient generation of thousands of candidate layouts. The user selects from among a set of modular templates to create a design and all simulation files are generated with the click of a button.

Thesis (M.S.)--University of Wisconsin--Madison, 1962. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 75-76).

The inefficient logistics in the construction industry is wasting vast amounts of time and resources. The major contracting firms are aware of the problem and have developed new logistics systems to reduce the waste, but all in vain. The developments are not accepted in practice. This thesis seeks to find and then reduce the factors that make implementation difficult. A literature review provides a theoretical framework. Both a quantitative and a qualitative study are addressed to site managers in larger contracting firms, as well as their suppliers. Results reveal that the three major obstacles are organisational inertia, communication difficulties and poor knowledge management. To overcome these problems, both current theories and empirical results suggest that problems and solution should be shared between production managers on seminars or similar. Know-how must be retained and shared between projects by developing standards for knowledge management on central level in the organisation.

Published Article / RFID can work in conjunction with sensors in material handling especially on a conveyor belt. A dozen different graded tagged products can be picked up by the RFID system in real-time and transported to respective chutes into automatic guided vehicles (AGV) for transportation to specific storage locations. The development of this system is now at an advanced stage. Our predictions to date show that the application of RFID in material handling in a manufacturing environment can assist in the fast flow of components throughout the assembly line beyond what available systems can do.

Initially, this research programme investigated training methods to improve strengthrelated material handling performance in the British Army. A widely used training programme was evaluated for its effectiveness in improving material handling, and found to provide some significant but small improvements. Modifications to the training programme, including the use of a large strength-training element, were devised based on prior research evidence. The modified training programme was evaluated and compared with the original programme, and shown to be significantly more effective at improving material handling. Any means to improve the effectiveness of strength training per se would further improve the effectiveness of the modified training programme. Consequently, a potential means to improve the effectiveness of strength training via postexercise nutritional supplementation was investigated. The encouraging but not statistically significant results suggested further research to evaluate the potential of the supplementation regimen and also to better illuminate the possible mechanisms. An evaluation of the hormonal and metabolic responses to varying combinations of resistance exercise and supplementation provided little additional evidence to support the effectiveness of the supplementation regimen. However, the likely mechanism of the effect that may exist was better identified as a direct effect of insulin or amino acid availability on muscle cell growth, rather than a reduction in circulating cortisol concentration.

No description available.

The motive of this research is to develop a good stacking method with an automatic material handling system and the procedures that can increase productivity, reduce production costs, and prevent labor injury. A diversity of products leads to a number of different kinds of stacking problems. Much research has been done focusing on two-dimensional arrangement for rectangles, circles or irregular shapes, and threedimensional regular-shaped objects such as rectangular boxes. To solve stacking problems, many algorithms such as the genetic algorithm, simulated annealing and other heuristic algorithms have been proposed. The three-dimensional stacking problem has a practical application in the transportation, manufacturing, and construction industries. There has been relatively little emphasis on three-dimensional irregular objects; however, stacking three-dimensional irregular objects has become more common in industry. In this thesis research, three heuristic algorithms are proposed to stack irregular stone pieces nested in a container with multiple layers. Primary functions of the heuristic algorithms include three major parts. First, it approximates irregular shapes to a cluster of straight lines. Secondly, it arranges the approximated angles one-by-one with the proposed step-by-step rule. Finally, it considers the weight of the stone pieces from the pixel calculation for reasons of stability. The first and second algorithms are based on the area and angle of the stone piece and the third one is based on the approximated weight of the stone. An automatic real-time stacking system including pneumatic devices, sensors, relays, a conveyor, a programmable logic controller, a robotic arm, and a vision system was developed for this study. The algorithms developed were tested by this automatic stacking system for better utilization. Three performance measures were presented in the experimental result. Comparisons between the results from three proposed algorithms and that from the bottom-back-left algorithm are made. Experimental data demonstrate that the utilizations and the stabilities of the three proposed algorithms are statistically better than that of the bottom-back-left algorithm. However, the cycle times of the three proposed algorithms have no statistical difference from that of the bottom-back-left algorithm. In addition, a statistical test between each proposed algorithm is also conducted. Both the utilizations and stabilities have statistical differences between each proposed algorithm while the cycle times do not. The results of this study show that the algorithm developed works effectively for solving the stone-pieces stacking problem.

Participatory ergonomics (PE) is a macroergonomics approach in which the end-users actively participate in developing and implementing the technology. PE can be an effective method for involving front-line workers in analyzing and redesigning their own jobs. PE can be used at the macro-level, the micro-level, or somewhere in between. At the macro-level, the focus of the PE program is across an entire organization or work system. At the micro-level, the focus of a PE approach is on a particular task, workstation, or product. A major benefit for using PE is that workers are more likely to accept changes to their job if they participate in the redesign. Furthermore, workers' motivation, job satisfaction, and knowledge are enhanced through the participatory process. There are many case studies that describe successful PE approaches. These studies, however, lack a control group or comparison group and so changes in the workplace (e.g., a reduction of musculoskeletal injury) cannot be attributed directly to the interventions resulting from the PE program with certainty. Quantifying the effects of PE is difficult because of problems in trying to isolate variables. Confounding variables are often difficult to contain. This study quantified some of the effects of PE by utilizing a controlled experimental design in the laboratory in which participants analyzed and redesigned a manual material handling job. The effects of this PE approach were quantified by measuring a reduction of risk factors associated with the job and by measuring a lift index of the lifting task that indicates a risk for injury. Many authors state or infer that some degree of ergonomics training should be given to the participants in a PE approach. However, the effects of providing ergonomics training to participants in these types of participatory approaches are unclear. This research evaluates the effects of providing the participants with basic ergonomics instruction relevant to the job being evaluated and redesigned. Also, this research suggests if the NIOSH lifting equation can be an effective tool in a participatory ergonomics approach in the redesign of a manual material handling job that involves lifting tasks. A 2-factor, between-subjects design was used. Participants consisted of 32 volunteers (16 males and 16 females). Only individuals that have had no prior ergonomics knowledge were considered for the subject pool. Participants performed a simulated manual material handling job in the laboratory. After performing the job, some subjects were given ergonomics training and/or instructed on how to use the NIOSH lifting equation for manual lifting tasks. The participants were then asked to redesign the original job. The participants' redesigns were compared to the redesigns of the control subjects (who received no ergonomics instruction and did not use the NIOSH lifting equation). The subjects who received the ergonomics instruction identified significantly more risk factors in the original job and eliminated significantly more risk factors in the redesign than the control subjects. The subjects who learned and used the NIOSH lifting equation also identified significantly more risk factors in the original job but did not eliminate significantly more risk factors in the redesign. The subjects who received the ergonomics instruction and who used the NIOSH lifting equation were not shown to have an advantage over the subjects who received the ergonomics instruction alone. The group that received the ergonomics training performed optimally with respect to the other experimental groups. Implications for participatory ergonomics approaches are discussed. / Master of Science

I takt med att tillverkande företag ökar sin försäljning ökar också produktionen. En ökad produktion kommer så småningom att kräva mer yta för en större maskinpark när de ordinarie maskinerna inte längre räcker till. Om produktion sker mot lager kommer kraven på lageryta samtidigt att öka. Både maskiner och lager tar plats och är företaget trångbodda redan innan expansionen och möjligheterna till utbyggnad inte är stora krävs alternativa lösningar på hur lokalerna kan utnyttjas på ett effektivare sätt. En sådan lösning kan vara AutoStore, ett tredimensionellt automatlager. Ett sådant lager kan underlätta optimering av lagerytan och är anpassningsbart då det kan implementeras i de flesta lokaler. Denna studie syftar till att besvara ett antal frågor som berör materialhanteringen vid byte av ett manuellt lagersystem till AutoStore. Studien har genomförts på ett fallföretag som planerar att implementera detta automatiska lagersystem. Problemfrågorna berör vilka artiklar som är lämpliga att lagerföra i AutoStore, i vilka kvantiteter de bör förpackas samt hur flytten från det gamla till det nya lagret ska genomföras utan att riskera leveranssäkerheten. Studien har genomförts med hjälp av litteratur för att få ett teoretiskt perspektiv samt intervjuer och studiebesök på såväl fallföretaget och på andra företag som redan har utfört en implementering av AutoStore för att få ett praktiskt perspektiv. De arbetsprocesser som berör materialhanteringen har beskrivits genom hur de fungerar både innan och efter en implementering för att kunna jämföra skillnader. Studien resulterade i beräkningsmodeller och matriser som ska underlätta valet av vart en artikel passar bäst, i ställage eller i AutoStore samt i vilka förpackningskvantiteter som är lämpliga för att underlätta plock. Vidare presenteras riktlinjer för vad som bör tänkas på vid en flytt till AutoStore. / As manufacturing companies increase their sales they also increasing their production. An increased production will eventually require more space area for a larger machinery as the regular machines no longer suffice. If production for stock is used, the demand for warehouse space will at the same time increase. Both machinery and storage require space and if the company is short on space even before the expansion and the potential for remodelling is low, this might require alternative solutions on how the space can be utilized in a better way. Such a solution can be AutoStore, a three-dimensional automated warehouse. Such a warehouse can facilitate a better use of the bearing surface and is adaptable as it can be implemented in most environments. This study aims to answer a number of questions relating to materials handling when changing from Manuel warehouse-system to AutoStore. The study was conducted on a case company planning to implement this kind of warehouse. The problem questions concern what items are suitable to store in AutoStore, in what quantities they should be packaged and how the switch from the old to the new warehouse could be implemented without jeopardizing security of supply. The study was conducted with the help of literature to get a theoretical perspective as well as interviews and visits on both the cases company and other companies that have already undergone an implementation of AutoStore to get a practical perspective. The work processes involving material handling described how they work both before and after an implementation of AutoStore to compare the differences. The study resulted in models and matrixes that will facilitate the choice of where an article is best suited, at racking storage or AutoStore and in what packaging quantities that are appropriate to facilitate picking. Furthermore, guidelines are presented for what should be thought of before switching to AutoStore.

Thesis (M.B.A.)--University of Hong Kong, 1984.