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In pulp and paper the modelling and simulation of the pulp production processes was the first major application. Since then several other applications have been realised though papermaking has never been on the lead concerning the use of computer-based modelling and simulation. The complex nature of the materials is one of the most demanding challenges and the biggest hurdle for any electronic description of the papermaking process or paper itself. So other industries took the lead and it is now for the paper industry to learn from these industries what can be done with the help of computers to control or optimise processes or to design new grades. The application of results gained with the use of modelling and simulation techniques in pulp and paper manufacturing processes has helped the industry to, for example, reduce emissions and increase the productivity and cost-efficiency of the processes. Still there are many important tasks open. A better understanding of the mechanisms of the processes and their control loops has to be achieved in order to further improve the paper quality, stabilise the wet-end chemistry, and enhance the runnability. Important features to be developed are new process designs, efficient process monitoring and systems that offer decision support during operation. In this paper a review of the state of the art on modelling and simulation in the pulp and paper industry is presented as well as further research needs. [ABSTRACT FROM AUTHOR]

The critical role that numerical simulation plays in additive manufacturing has stimulated research on the effectiveness and potential applications of mesh-free, particle-based discretisation techniques. These methods excel at handling fluid flows and are viable alternatives to the mesh-based techniques typically used in commercial simulation software. In this paper, we review recent advances in developing computational models for metal additive manufacturing (MAM) processes using particle methods, in the theoretical understanding of the fundamental mechanisms that control such processes at the powder (or melt pool) scale, and in the predictability of physics-based modelling approaches. The paper explores the applicability and performance of particle-based methods in simulating powder bed fusion, directed energy deposition, and binder jetting processes. Since the progress of MAM relies on systematic material-process-structure realisations which are often impossible to sense or observe experimentally, developing efficient particle-based and multiscale simulation tools can be essential to achieving this objective through in-situ process control and optimisation. [ABSTRACT FROM AUTHOR]

The characteristic of layered manufacturing is the incremental build-up which inevitably leads to the staircase effect. One method to reduce this effect is to optimise part orientation and to apply adaptive slicing procedures. Although layer thickness will be decreased in some regions, process efficiency can be kept to a reasonable level. This paper presents different approaches of adaptive slicing for laser-based applications in consideration of limited range of thickness variation to ensure the mechanical part properties. In contradiction to previous work, the number of applied layer thicknesses is limited due to the associated process parameters. In order to optimise the slicing process and to obtain the best results, this paper presents a practicable approach based on existing work to simulate adaptive slicing. To underline the potential of non-uniform slicing, illustrative examples will show possible improvements in the case of replacing the uniform slicing procedure. [ABSTRACT FROM AUTHOR]

Injection molding is a very mature technology, but the growth of layer-build, additive, manufacturing technologies (rapid prototyping, RP) has the potential of expanding injection molding into areas not commercially feasible with traditional molds and molding techniques. This integration of injection molding with rapid prototyping has undergone many demonstrations of potential. What is missing is the fundamental understanding of how the modifications to the mold material and RP manufacturing process impact both the mold design and the injection molding process. In addition, numerical simulation techniques have now become helpful tools of mold designers and process engineers for traditional injection molding. But all current simulation packages for conventional injection molding are no longer applicable to this new type of injection molds, mainly because the property of the mold material changes greatly. In this paper, an approach to accomplish numerical simulation of injection molding into rapid-prototyped molds is established and a corresponding simulation system is developed. For verification, an experiment is also been carried out with an RP fabricated SL mold. Stereolithography (SL) is an original and typical rapid-prototyping method, which is chosen as the study object in the paper. [ABSTRACT FROM AUTHOR]

This paper describes the development of a cohesive framework for discrete event simulation, and the embedded decision processes of a system being modeled. The work presented in the paper is an effort to develop a scientific base for simulation modeling. The paper addresses the need for separate and structured representations of physical and logical entities of a manufacturing system for simulation modeling. The formal and hierarchical constructs defined for physical and logical entities are based on a state-space representation that allows the integration of physical and logical facets in a model with varying degrees of detail. All the entities of a manufacturing system, from the most primitive to the most sophisticated, can be represented in a model by using one of the symbolic structures provided. The framework also describes the simulation dynamics by using the defined constructs. [ABSTRACT FROM AUTHOR]

This research presents guidelines to design control processes where improving quality is achieved by improving the manufacturing consistency through the use of intelligent process control. Conventional control processes cannot include the theoretical knowledge, experimental knowledge, and expert knowledge available concerning the product. A hybrid intelligent process control (IPC) combining a continuous simulation (CS) and an artificial neural network (ANN) can make this knowledge available to the operator for process control. This paper presents a methodology for combining the CS and ANN to achieve real-time process control. A human-machine interface (HMI) is included in the process to aid operators in communication with the CS/ANN hybrid IPC. The result of the new process is a real-time process control advisor (RTPCa). A case example for the methodology of formulating, formalizing, validating, and evaluating the RTPCa is given. The case studied concerns galvanizing continuous sheet steel at a steel plant. The CS is written in SIMAN, and the ANN in C. The research validates and evaluates the RTPCa using plant data, simulation output, and face validation by plant personnel. The authors conclude that the benefits of the RTPCa over other forms of IPC include better process communication to the operator, robustness to moderate changes in system parameters, the flexibility to retrain the ANN if conditions change dramatically, and the computation speed necessary for real-time process control. This methodology has further applications to other continuous processes where quality is determined by manufacturing consistency of the product, such as in the pulp paper and film processing industries. [ABSTRACT FROM AUTHOR]

This paper devotes both analytical and experimental efforts in developing a comprehensive dynamic model for an articulated steering wheel loader. The general motion of a wheel loader without suspension is described by seven degrees of freedom (DOF) (three for translation and four for rotation) in this model, which can be used to study the problem of wheel loader dynamics on slopes and over obstacles. A scale wheel loader was designed and manufactured to validate the dynamic model in three conditions (turning on level ground, turning on slopes, and passing over obstacles). The test results reasonably agree with the simulation results. The developed dynamic model was found to be useful and could serve as an important tool for analysing the stability of wheel loaders. [ABSTRACT FROM PUBLISHER]