Center for Advanced Manufacturing and Lean Systems
Permanent URI for this communityhttps://hdl.handle.net/20.500.12588/879
The Center for Advanced Manufacturing and Lean Systems was established in 2007 at the University of Texas at San Antonio (UTSA) to provide the greater San Antonio and south Texas area industries, public and private agencies with a one-stop, unique source of expertise in flexible and lean technologies and systems, state-of-the-art technology applications with the following two thrust areas:
Advanced Manufacturing Systems: effective and efficient integration and synthesis of automation technologies, human resources, and decision-making models for design, planning, scheduling, and control of production of goods and delivery of services.
Lean Enterprise Systems: systematic elimination of waste (anything that does not add value) across the enterprise by using various lean and six-sigma tools and methodologies to continuously improve value creating processes in manufacturing and service sectors.
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Item Procurement policy of vulnerable parts with jointly distributed lifespan(DEStech Publications, Inc., 2014) Li, Cun Rong; Sarker, Bhaba R.; Yi, Hui Zhi; Yu, MengVulnerable parts exist in most machines or equipment. Failure of those vulnerable parts may result in damage of the machine or the product, and may sometimes cause unnecessary down-time within a production cycle, all of which increases the production costs. Therefore, such failures should be minimized and the parts should be replaced at a point before the end of their expected lifespan, which usually follow some kind of distributions and can be known due to its mass usage attributes. On the other hand, too early replacement of the parts also means increased maintenance costs, increased inventory, and increased parts purchasing cost. This study developed a mathematical model to deal with the issue of determining the optimal stopping time of vulnerable tools. Under the preemption situation, a periodic procurement policy is investigated simultaneously to find the optimal order cycle and eventually minimize the total cost. A case study is given to show the feasibility of the model and several parameters are analyzed to show the impact on the total cost and decision variables.Item User phase information based inventory policy for supply chain systems with remanufacturing(DEStech Publications, Inc., 2014) Dong, Ming, Ph. D.; Zhu, Feng; Zhang, DaliMost of the literatures for inventory management policies of supply chain systems with remanufacturing had focused solely on warehouse operation. The existence of its optimal policy has yet been confirmed. In addition, the IT platform nowadays has been well developed so that user phase alignment could be executed at relatively low cost and it is a global phenomenon for companies to pursue cross-tier stretch along its value chain. In this study, a supply chain model comprised of three major biz entities (warehouse, remanufacturing facility and user phase) is presented. An optimal (s,S) type policy for this model is first introduced under the non-leadtime assumption and then extended to the leadtime scenario. The theoretically optimal policy is not applicable as a consequence of lacking information with regard to the failure product's return flow. In order to solve this issue, data mining within the user phase is executed and the specification of user phase information that serves to implementing the optimal policy is articulated. Additionally, numerical experiments are presented to verify the optimality of the (s,S) type policy and the contribution of user phase information sharing to inventory cost reduction.Item Production as a key factor for driving competitiveness in manufacturing industry(DEStech Publications, Inc., 2014) Majuri, Matti; Tapaninaho, Mikko; Tuokko, Reijo; Torvinen, Seppo J.The importance of small and medium sized companies as a leader for globalization has been recognized through various sources. One class of these companies is called the Hidden Champions. A Hidden Champion company thrives to operate as a global leader in a niche market. The competence factors of the hidden champion companies have been identified in a previous research conducted by Hermann Simon. The competence factors do not include or define the role of production or the production strategy. The purpose of this paper is to study the impact of the decision made in production strategy to correspond to the identified competence factors. This study includes a definition of the hid.Item A constructive cooperative coevolutionary algorithm applied to press line optimisation(DEStech Publications, Inc., 2014) Glorieux, Emile; Svensson, Bo; Danielsson, Fredrik; Lennartson, BengtSimulation-based optimisation often considers computationally expensive problems. Successfully optimising such large scale and complex problems within a practical timeframe is a challenging task. Optimisation techniques to fulfil this need to be developed. A technique to address this involves decomposing the considered problem into smaller subproblems. These subproblems are then optimised separately. In this paper, an efficient algorithm for simulation-based optimisation is proposed. The proposed algorithm extends the cooperative coevolutionary algorithm, which optimises subproblems separately. To optimise the subproblems, the proposed algorithm enables using a deterministic algorithm, next to stochastic genetic algorithms, getting the flexibility of using either type. It also includes a constructive heuristic that creates good initial feasible solutions to reduce the number of fitness calculations. The extension enables solving complex, computationally expensive problems efficiently. The proposed algorithm has been applied on automated sheet metal press lines from the automotive industry. This is a highly complex optimisation problem due to its non-linearity and high dimensionality. The optimisation problem is to find control parameters that maximises the line's production rate. These control parameters determine velocities, time constants, and cam values for critical interactions between components. A simulation model is used for the fitness calculation during the optimisation. The results show that the proposed algorithm manages to solve the press line optimisation problem efficiently. This is a step forward in press line optimisation since this is to the authors' knowledge the first time a press line has been optimised efficiently in this way.Item From machine utilisation to flow time: Effects of Lean transformation on scheduling(DEStech Publications, Inc., 2014) Tokola, Henri; Niemi, Esko; Kyrenius, PekkaThe Lean paradigm transforms a production company from utilisation-centric planning into a system in which other operating conditions such as short flow times, local control, and reduction in variation are weighted as well. This paper studies how the scheduling of production changes when the above three conditions are implemented. Their effects are studied by constructing an optimisation model for the scheduling of a flow shop. The optimisation model is based on the following ideas. First, when the flow time is emphasised, the objective of the scheduling changes from utilisation to a short flow time. Second, if local control is used, it means that the optimisation is done locally, i.e. individually at each station, and it concerns the makespan at the station. Third, if the variation is reduced, the processing times and arrival times have less variation and the scheduling can force the flow times to have less variation by using first-in-first-out (FIFO) sequencing. The experimental results achieved using the model describe how and in which order the operating conditions under study should be implemented in the scheduling. For example, if utilisation is important, local control and FIFO should not be used before variation is reduced.Item Process variability reduction by using the design of experiment— A case study(DEStech Publications, Inc., 2014) Machac, Jan; Steiner, FrantisekLow process variability and capability index might be some of customer's requirements. Therefore it is necessary to fulfil these requirements and guarantee them in the future. Since state-of-art companies that want to keep up with competitors have to consider all actions which might prevent losses or customer's dissatisfaction. This paper deals with possibilities how to decrease the process variability and satisfy customers. For process variability decrease, statistical experiments were carried out. The paper contains a case study devoted to the usage of design of experiment (DOE) in the production process. The case study reveals ways of dealing with real production problems and offers an effective treatment.Item Roughing an impeller: A review(DEStech Publications, Inc., 2014) Suhaimi, M. A.; Kim, Dong-Won; Cuka, Besmir K.Impeller is a rotating device, which transforms fluid flow from axial to radial direction. It consists of several identical, twisted blades with ruled surfaces, which are attached to a hub surface. Commonly, impeller needs high-speed rotation in order to increase the pressure flow of a pump or turbine engine. High machining accuracy is vital in producing an impeller. In this sense, there are many issues in producing a high quality impeller. Not enough information has been provided to guide new researchers in this field in the meantime. To overcome this problem, therefore, this paper reviews existing researches associated with impeller machining, focusing on the roughing strategies. An extensive study covers the literature from 1970 to 2013, mapping out research issues regarding roughing strategy in details. This paper classifies the impeller roughing strategy issues in a chronological order according to the main idea and issues. A clear analysis of machining strategies provided by dividing them into 4 categories; (1) improving machining time, (2) avoiding tool collisions, (3) undercut avoidance, and (4) chatter avoidance. Critics on the existing work and research trends reported as discussions and conclusion.Item Classification of reconfiguration resources and lead time for reconfigurable manufacturing systems(DEStech Publications, Inc., 2014) Puik, Erik; Telgen, Daniel; Moergestel, Leo van; Ceglarek, DarekManufacturing technology can improve the turnover of a company if it enables fast market introduction for volume production. Reconfigurable equipment is developed to meet the growing demand for more agile production. Modular reconfiguration, defined as changing the structure of the machine, enables larger variation of products on a single manufacturing system; these solutions are called Reconfigurable Manufacturing Systems (RMS). The quality of RMS, and the required resources to bring it to reliable production, is largely determined by a swift execution of the reconfiguration process. This paper proposes a method to compare alternatives for the ways to implement reconfiguration. Three classes of reconfiguration are defined to distinguish the impact of the proposed alternatives. The procedure uses a recently introduced index method for development of RMS process modules. This index method is based on the Axiomatic Design theory. Weighing factors are used to calculate the resources and lead time needed to implement the reconfiguration process. Application of the method leads to quick comparison of alternatives in the early stage of development. Successful execution of the method was demonstrated for the manufacturing process of a 3D measuring probe.Item Rough-cut machining an impeller with 3-axis and 5-axis NC machines(DEStech Publications, Inc., 2014) Suhaimi, M. A.; Kim, Dong-Won; Lee, Jong-Yeong; Velasquez Arriaza, OscarThis study presents an efficient rough-cutting strategy for machining a centrifugal impeller. Much of the machining time is consumed in rough cutting, where unnecessary stock materials are removed in between impeller blades. Thus, most of researchers focus on 5-axis rough machining of an impeller, controlling all the five axes simultaneously as fast as possible. In previous research, we introduced a 3-axis machining strategy that removes as much material as possible from the areas between blades. Thus, the main purpose of the research was to improve the machining efficiency by reducing the machining time. We achieved 19 percent of total machining time reduction by using the 3-axis rough machining. For further improvement, this paper will introduce an improved 3-axis machining strategy by applying feed-rate scheduling for more efficient rough cutting. There are two types of feed rate scheduling, namely, cutting force and material removal rate based scheduling. This research will focus on feed-rate scheduling based on cutting force to increase the feed-rate onto an allowable level. Current research in feed-rate scheduling applies cutting force calculations for each cutter-workpiece engagement, experimenting with different depth-of-cut layers. In this paper, we will calculate cutting force for each cutter-workpiece engagement by employing a finite element method. Cutting tool and workpiece geometry will be meshed and analyzed to find out best feed-rate scheduling. The rest of material that is left from the 3-axis machining will be removed by 5-axis machining. The result shows that by applying this hybrid roughing strategy, namely, 3-axis machining with feed-rate scheduling and 5-axis machining, total rough machining time can be reduced significantly up to 43 percent.Item A foresight study on future trends influencing material consumption and waste generation in production(DEStech Publications, Inc., 2014) Shahbazi, Sasha; Sjödin, Carina; Bjelkemyr, Marcus; Wiktorsson, MagnusThere are boundless upcoming factors that influence future of material waste in production. This broad range of factors needs to be scanned, categorized and analyzed in a structured way. This paper by a foresight study, aims to give an insight and increase awareness about external macro-level future trends concerning raw material consumption and waste generation in production. A limited pilot study indicated that technological forecasting and some reaction upon obvious trends are being taken, although in an ad hoc manner and without structured tools. However, political influences, economic visions and social-cultural shifts were seldom or never discussed. External macro trends and tendencies were examined through PEST analysis to identify potentials and opportunities influencing strategic decisions and innovation initiatives. It is vital to understand the whole picture of possible changes and not only considering the technological trends, but also other relevant development areas that might affect production in different ways.Item A fast and accurate recognition system for flexible grasping of electronic goods(DEStech Publications, Inc., 2014) Woegerer, Christian; Rooker, M.; Angerer, Alfred; Kopf, Ch.; Pichler, A.Automated packaging is becoming more and more interesting for various production sites even in Europe. However, in many companies the packaging process can only handle a limited amount of products. This leads to a very inflexible packaging and a bottle neck in the production. Most of the time for new products, the packaging system needs to be modified. One of the main components in an automated packaging process is the recognition and then the grasping of the objects that need to be packed. For different products mostly a different gripping system is required. In this paper, solutions from a research project are presented which enables the recognizing as a basis for flexible grasping of different products. These solutions includes a flexible pose recognition for different objects by a low cost system based on Kinect or or Asus Xtion cameras.Item The machining parameter design using fuzzy theory in electrical discharge machining drill(DEStech Publications, Inc., 2014) Byun, Kyung-tae; Kim, Jong-Min; Heo, Eun-Young; Lee, Cheol-SooElectric discharge machining drill (EDM-drill) is a process to machine fine holes. EDM-drill is specially used for drilling of difficult-to-cut materials such as high-strength steel, titanium and cemented carbide processing. The machining parameters of EDM-drill include voltage, PWM (pulse width modulation), machining speed, discharge capability, flushing rate, etc. These machining parameters affect the accuracy of the work-piece, the wear consumption of electrodes, surface roughness and machining time. As there are many machining parameters and machined results of work-pieces, it is difficult to establish the relations between the machining parameters and the results. A fuzzy system is presented to predict the relations. The machining parameters and results are normalized using the principal component analysis (PCA) and expressed as membership function (MF). Fuzzy rules are created by fuzzy rule-base which from MF and fuzzy inference is carried out. By this method, it is possible to obtain reasonably the machining parameters, which is necessary for the required machined results. On other hands, the machined results can also be predicted with the given machining parameters. The proposed fuzzy system is implemented using MATLAB. Actual experiments and Fuzzy inference are carried out in same machining conditions and the results are compared.Item Technologies guiding the future of robotics in manufacturing(DEStech Publications, Inc., 2014) Flannigan, William C; Evans, Paul T.; Edwards, Shaun M.; Hvass, Paul B.Industrial robots, both stationary and mobile, have been used in manufacturing applications for decades and are most often employed based on requirements for dedicated and repetitive manufacturing operations. Industrial robot capabilities have continued to advance in areas such as payload, accuracy and speed. Looking to the near-future, the use of robots must also transition to operate in dynamic environments for high-mix low-volume production. A variety of affordable technologies are emerging and blending to bridge the gap between the traditional use of industrial robotics and the future where robots react to consumer-driven customized product demands. This paper is intended to be informational in nature and will present applied technology development to overcome some of the historical limitations in the use of automation for complex industrial tasks. Additionally, this paper will describe internal and industry sponsored research efforts that are giving robots greater intelligence, more flexibility and greater ability to work collaboratively with humans.Item On a paired-t confidence interval based ranking and selection method(DEStech Publications, Inc., 2014) Wu, Yifan; Liu, Liping; Li, Shu-XiaSimulation optimization is a widely used methodology for complex stochastic system design. Though the simulation provides a flexible tool for model building, the optimization process could be very challenging due to the cumbersome computing times. A paired-t confidence interval based ranking and selection method is developed to tackle such a problem. The survive probability of each candidate system is calculated with the lower and upper bounds of the confidence interval obtained using paired-t comparison method. The proposed method is tested with several numerical examples. The experimental results suggest that the proposed method outperforms the other classical Ranking and Selection procedures.Item Improving lumber yield using a dual system(DEStech Publications, Inc., 2014) Thomas, R. Edward; Espinoza, Omar; Buehlmann, UrsRough mills embody the process of cutting up kiln-dried lumber to components used by discrete wood products manufacturers to manufacture products like furniture, kitchen cabinets, flooring, or other items. Rough mills traditionally have either ripped the lumber first (e.g., the lumber is first cut into strips lengthwise) then cut the strips to the required part lengths or they crosscut the lumber first to part lengths (e.g., cutting the lumber to shorter, full width segments) then ripped the segments to the required part widths. Both processes offer advantages and disadvantages and, depending on the input lumber geometry (e.g., size) and the cutting bill requirements (e.g., the size of the resulting components) may result in higher yield for individual cases. Using ROMI 4.1, a rough mill simulator that simulates real-world rough mills and can combine rip and chop operations, this study investigated the potential benefits from using such a dual system. Findings suggest that cutting bills requiring small parts when cutting from lower quality lumber produce better yield when a rip-first approach is used, while cutting bills asking for wide and long parts perform better when material is chopped first. However, in every case, yield can still be improved when the decision to rip or to chop first is made on each individual board.Item Requirements for manufacturing operations management and control systems in a dynamic environment(DEStech Publications, Inc., 2014) Järvenpää, Eeva; Tokola, Henri; Salonen, Tapio; Lanz, Minna; Koho, Mikko; Tuokko, ReijoIn today's highly dynamic manufacturing environment smooth information flow between planning and shop floor level is essential to ensure rapid reaction to changes. Unfortunately, the currently utilized dispersed MS Excel applications for production scheduling and control don't provide such an information flow. The transparency between different operational levels, and therefore the big picture, is lacking. To illustrate these challenges, this paper presents the first results of interviews, conducted among Finnish machine building companies, relating to the current practices and challenges as well as future requirements for manufacturing operations management and control systems.Item Impact of finite life cycle to a consignment stocking supply chain with uncertain demand(DEStech Publications, Inc., 2014) Yi, Hui Zhi; Sarker, Bhaba R.; Li, Cun RongThere are usually two reasons that force a supply chain to adopt the consignment stocking policy: the high demand variance and the high risk of obsolescence. This research aims to study the influences of these two issues to a consignment stocking integrated supply chain. To better reflect the real situation in the engineering practice, the buyer's warehouse limitation and a reducible lead time is also considered. A five-variable mixed-integer optimization model that aimed to minimize the annual joint total expected cost (JTEC) is developed under the general assumption that the production rate, the number of shipments and the shipping quantities are all fixed. To distinguish the Consignment Stocking policy from traditional ones, the holding cost is considered to consist of a storage component and a financial component. Due to the complexity of the objective function, traditional mathematical methods are cumbersome. As a result, closed-form solutions for the model are not provided. Instead, a novel doubly-hybrid meta-heuristic algorithm is employed to solve the problem. A numerical example is used to illustrate the solution procedure and the efficiency of the doubly-hybrid meta-heuristic algorithm.Item Batch size optimization based on production part cost(DEStech Publications, Inc., 2014) Windmark, Christina; Spang, Kathrine; Schultheiss, Fredrik; Ståhl, Jan-EricWhen investigating different location and/or system designs the possible variables to take into consideration can differs between the alternatives. Different production system will have different optimal working conditions and hence should be compared with parameters suitable for the actual production system. When planning production and calculating production costs the batch size is of high interest. Based on a manufacturing part cost model, this paper will present a new model, close connected to the production system, integrating production performance, set-up times, material costs, material handling costs and tied capital, giving the production economic optimal batch size. The aim is to give companies a model for determining the economic optimal batch size in order to use this knowledge to make strategic decisions regarding production planning. Mathematical simulations are performed to analyse the differences in result from the developed model and Wilson's existing standard method for calculating the economic order quantity, hence to verify the importance of making an in-depth analysis, taking the production system into consideration. The advantage of the developed model is the usage of production costs based on variable batch sizes, giving a more accurate outcome.Item Balancing tradeoffs between machining time and energy consumption for impeller rough machining(DEStech Publications, Inc., 2014) Velasquez Arriaza, Oscar; Kim, Dong-Won; Lee, Jong-Yeong; Suhaimi, M. A.Electrical energy is directly linked to society prosperity across the globeItem Advantages of using hybrid manufacturing platforms to realize decentralized manufacture(DEStech Publications, Inc., 2014) Kendrick, Blake A.; Dhokia, Vimal; Newman, Stephen T.Manufacturing has traditionally been the domain of centralised factories, set-up and optimised to make a sole product or product-range. Whilst the in-house efficacy of such systems has been greatly improved due to lean six-sigma methodologies, the wider scale distribution and supply system has undergone little to no transformation over the past century. Previous research pertaining to distributed manufacture, cloud-manufacture and reconfigurable systems has provided several decentralised models using traditional manufacturing capabilities. Though to date they have not been fully realised due to practical limitations. This paper outlines the scope for hybrid manufacturing platforms – using a plurality of processes on a single motion platform, to manufacture products in a decentralised network. Social, economic and environmental ramifications of adopting such a system under particular use cases, such as in shops, community areas or in individual households, are highlighted. The combination of several key processes, including measurement, will allow users to manufacture parts with minimal intervention. A move to personal fabrication would allow greater personalisation and convenience for the end user