Development of a novel 3D simulation modelling system for distributed manufacturing

This paper describes a novel 3D simulation modelling system for supporting our distributed machine design and control paradigm with respect to simulating and emulating machine behaviour on the Internet. The system has been designed and implemented using Java2D and Java3D. An easy assembly concept of drag-and-drop assembly has been realised and implemented by the introduction of new connection features (unified interface assembly features) between two assembly components (modules). The system comprises a hierarchical geometric modeller, a behavioural editor, and two assemblers. During modelling, designers can combine basic modelling primitives with general extrusions and integrate CAD geometric models into simulation models. Each simulation component (module) model can be visualised and animated in VRML browsers. It is reusable. This makes machine design re-configurable and flexible. A case study example is given to support our conclusions

Manufacturing Processes Management with Usage of Simulation Tools

Simulace výrobních procesů pomáhá optimalizovat výrobu, logistiku a další systémy, díky čemuž dochází ke snižování nákladů a racionalizaci vnitropodnikových procesů. Využitím diskrétní simulace programu Witness Power with Ease se v diplomové práci optimalizuje logistický tok materiálu ve společnosti Hella Autotechnik, s.r.o. Práce přibližuje metody a jednotlivé fáze tvorby modelu včetně jeho validace a navrhuje vylepšení, díky kterému by mělo dojít ke snížení nákladů na dopravní služby o 24 400 Kč měsíčně.By optimizing the logistics, production and other systems the simulation can reduce costs and rationalise business processes. By use of discrete simulation in software Witness Power with Ease is in this diploma thesis optimised logistical flow of material in the company Hella Autotechnik, s.r.o. The thesis introduces methods and particular phases of creating the model including its validation. The proposal in the diploma work suggests the improvement to lower the costs for the transportation services by 24,400 CZK per month.

Planning complex engineer-to-order products

The design and manufacture of complex Engineer-to-Order products is characterised by uncertain operation durations, finite capacity resources and multilevel product structures. Two scheduling methods are presented to minimise expected costs for multiple products across multiple finite capacity resources. The first sub-optimises the operations sequence, using mean operation durations, then refines the schedule by perturbation. The second method generates a schedule of start times directly by random search with an embedded simulation of candidate schedules for evaluation. The methods are compared for industrial examples

Aplikácia kognitivného modelu vizuálnej pozornosti v automatizovanej montáži

Zásobovacie zariadenia a podsystémy v štruktúrach montážnych systémov majú významné postavenie. Technickú zložitosť klasických zásobovacích zariadení a podsystémov je možné eliminovať pružnými programovateľnými automatizovanými zariadeniami. Informácie o spomínanom objekte zabezpečované senzorovými modulmi sa spracovávajú v riadiacom systéme zariadenia resp. na vyššej úrovni riadenia montážneho systému. Spracované informácie sú distribuované ako riadiace informácie výkonným jednotkám a prvkom, ktoré vykonávajú príslušné funkcie. Riadiace systémy programovateľných zásobovacích zariadení a podsystémov plnia viaceré funkcie napr. spracovanie informácií od senzorových jednotiek a modulov, správne vyhodnotenie polohy súčiastky a určenie postupu činnosti výkonných jednotiek a prvkov, distribúcia výkonných inštrukcií pohonovým jednotkám, atď. Programové vybavenie založené na využívaní kognitívneho modelu vizuálnej pozornosti charakterizuje nový prístup k riešeniu uvádzaných problémov. Pri vizuálnom vnímání scény obsahujúcej rôzne objekty a pre potrebu interakcie s určitým cieľovým objektom nachádzajúcim sa v tejto scéne je nutné aby systém upriamil svoju pozornosť na tento (cieľový) objekt. Tento mechanizmus je jedným z principiálnych prvkov videnia a podobne ako mnoho biologicky motivovaných systémov je veľmi výhodne využiteľný v praxi. Navrhovaný model je implementáciou mechanizmu vizuálnej pozornosti vo vytvorenom počítačom simulovanom prostredí.Logistic devices and sub - systems in the structures of assembly systems have significant position. Technical complexity of classical devices and sub - systems can be decreased by using of flexible programmable automated devices. Information's about objects provided by sensor modules are handled in processing system of the device, respective on the higher level of the assembly system. Executed information is distributed like processing information to executive units and elements. Control systems of programmable supply devices and sub - systems take handle of many functions, for example: processing information from sensor devices and modules, right calculating of the bearing of the component, distributing of executive instructions to actuating units, and many others. Software accessories based on the using of cognitive model of visual attention featured a new way of solving former problems. By visual reception the scenes contains miscellaneous objects and for the demand of the interaction with the target object is necessary that the system is need to be focused to this object. This mechanism is one of the pricipally elements of vision, and like many biologically motivated systems is very useful in practice. Designed model is an implementation of the mechanism of visual attention in the computer created simulation environment

Simulation Based Study of Safety Stocks under Short-Term Demand Volatility in Integrated Device Manufacturing.

© IEOM Society InternationalA problem faced by integrated device manufacturers (IDMs) relates to fluctuating demand and can be reflected in long-term demand, middle-term demand, and short-term demand fluctuations. This paper explores safety stock under short term demand fluctuations in integrated device manufacturing. The manufacturing flow of integrated circuits is conceptualized into front end and back end operations with a die bank in between. Using a model of the back-end operations of integrated circuit manufacturing, simulation experiments were conducted based on three scenarios namely a production environment of low demand volatility and high capacity reliability (Scenario A), an environment with lower capacity reliability than scenario A (Scenario B), and an environment of high demand volatility and low capacity reliability (Scenario C). Results show trade-off relation between inventory levels and delivery performance with varied degree of severity between the different scenarios studied. Generally, higher safety stock levels are required to achieve competitive delivery performance as uncertainty in demand increases and manufacturing capability reliability decreases. Back-end cycle time are also found to have detrimental impact on delivery performance as the cycle time increases. It is suggested that success of finished goods safety stock policy relies significantly on having appropriate capacity amongst others to support fluctuations

Commercial-off-the-shelf simulation package interoperability: Issues and futures

Commercial-Off-The-Shelf Simulation Packages (CSPs) are widely used in industry to simulate discrete-event models. Interoperability of CSPs requires the use of distributed simulation techniques. Literature presents us with many examples of achieving CSP interoperability using bespoke solutions. However, for the wider adoption of CSP-based distributed simulation it is essential that, first and foremost, a standard for CSP interoperability be created, and secondly, these standards are adhered to by the CSP vendors. This advanced tutorial is on an emerging standard relating to CSP interoperability. It gives an overview of this standard and presents case studies that implement some of the proposed standards. Furthermore, interoperability is discussed in relation to large and complex models developed using CSPs that require large amount of computing resources. It is hoped that this tutorial will inform the simulation community of the issues associated with CSP interoperability, the importance of these standards and its future

Modeling a complex production line using virtual cells

This chapter presents modeling and simulation of a complex multistage multiproduct production line with four closed loop networks configuration, which also act as a virtual cell. This allows for a greater understanding of the functions within the production line through the simplification of the production flow with the addition of buffers between the cells. Virtual cells are crucial in this instance due to the dynamic configuration, which could help production system designers in optimizing the complex configuration of production