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Number of results: 6
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Abstract

There exist numerous modelling techniques and representation methods for digital control algorithms, aimed to achieve required system or process parameters, e.g. precision of process modelling, control quality, fulfilling the time constrains, optimisation of consumption of system resources, or achieving a trade-off between number of parameters. This work illustrates usage of Finite State Machines (FSM) modelling technique to solve a control problem with parameterized external variables. The structure of this work comprises six elements. The FSM is presented in brief and discrete control algorithm modelling is discussed. The modelled object and control problem is described and variables are identified. The FSM model is presented and control algorithm is described. The parameterization problem is identified and addressed, and the implementation in PLC programming LAD language is presented. Finally, the conclusion is given and future work areas are identified.
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Authors and Affiliations

Grzegorz Andrzejewski
Wojciech Zając
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Abstract

The manufacture and consumption of market products show ever growing trends, and this means not only the supply and demand volume but also, to a higher and higher extent, searching for new products distinguishable from the variety of products on the market. Thus, it is necessary to find methods of functional, logical and structural combination of the so far existing engineering applications like CAx, RP/RT/RE, PDM/TDM, PPC/ERP, CE/SE and RDBMS techniques. A new challenge imposed on manufacturers by the competitive market is the so-called “product customization”, i.e. attending to an individual customer’s requirements in the features of a series manufactured product. The general objective of customisation is to elaborate features of a product, manufacturing processes, documentation and production organisation in such a way that the product’s individual features meet the customer’s requirements and its manufacturing process, price and service do not stray from series manufactured products.

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Authors and Affiliations

E. Chlebus
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Abstract

This paper presents a numerical model for the horizontal continuous casting of cast iron (HCCCI). A computational three-dimensional (3D) steady-state, coupled with fluid flow and heat transfer simulation model was developed and validated against experimental results to study the shell thickness and solidification of ductile cast iron. The study introduces the influence of an air gap at the melt-mould interface, which has long been known to have a detrimental effect on the efficiency of the process. The effect of the length and thickness of the melt-mould air gaps (also referred to as top air gaps) on solidification and remelting of the solid strand is studied. Parametric studies on top air gaps suggested a substantial effect on the solid and eutectic area at the top-outlet end of the die when the length of air gas was varied. This study serves to create a foundational and working model with the overall objective of process optimisation and analyzing the effect of operating process input parameters on the shell thickness of the strand.
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Authors and Affiliations

A. Chawla
1
ORCID: ORCID
N.S. Tiedje
1
ORCID: ORCID
J. Spangenberg
1
ORCID: ORCID

  1. Technical University of Denmark, Denmark
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Abstract

The article presents the results of the simulation studies concerning the impact of random production interruptions on the efficiency of multi-spindle machining centers. Four different machining center configuration models were developed using a dedicated class of stochastic Petri nets. In addition to the number of machine spindles, the number of simultaneously mounted parts, loading time of parts, their machining time, and reliability parameters regarding the frequency of machine interruptions caused by random factors were also taken into account as model parameters. A series of virtual tests was carried out for machining processes over a period of 1000 hours of operation. Analysis of the results confirmed the purpose of conducting simulation tests prior to making a decision regarding the purchase of a multispindle milling center. This work fills the existing research gap, as there are no examples in the technical literature of evaluating the effectiveness of multi-spindle machining centers.
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Authors and Affiliations

Roman STRYCZEK
1

  1. University of Bielsko-Biala, Faculty of Mechanical Engineering and Computer Science, Poland
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Abstract

In the era of smart manufacturing and Industry 4.0, the rapid development of modelling in production processes results in the implementation of new techniques, such as additive manufacturing (AM) technologies. However, large invest-ments in the devices in the field of AM technologies require prior analysis to identify the possibilities of improving the production process flow. This paper proposes a new approach to determine and optimize the production process flow with improvements made by the AM technologies through the application of the Petri net theory. The existing produc-tion process is specified by a Petri net model and optimized by AM technology. The modified version of the system is verified and validated by the set of analytic methods safeguarding against the formal errors, deadlocks, or unreachable states. The proposed idea is illustrated by an example of a real-life production process.
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Authors and Affiliations

Justyna Patalas-Maliszewska
1
ORCID: ORCID
Remigiusz Wiśniewski
2
ORCID: ORCID
Marcin Topczak
1
ORCID: ORCID
Marcin Wojnakowski
2
ORCID: ORCID

  1. Institute of Mechanical Engineering, University of Zielona Góra, Szafrana 4, 65-516 Zielona Góra, Poland
  2. Institute of Control & Computation Engineering, University of Zielona Góra, Szafrana 2, 65-516 Zielona Góra, Poland
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Abstract

The development of combustion systems construction is associated with the possibility of increasing the thermal or overall efficiency of an internal combustion engine. The combustion systems currently in use (mainly related to direct fuel injection) are increasingly being replaced by hybrid systems, including direct and indirect injection. Another alternative is the use of prechambers in new combustion systems. This article concerns the thermodynamic aspect of this issue – namely, the assessment of the inter-chamber flow of a marine engine equipped with a prechamber combustion spark ignition system. The research was carried out using mainly one-dimensional simulation apparatus, and detailed analyses were presented using three-dimensional modeling. The tests included the engine model at medium load. Differences in mass flows were shown at different diameters and different numbers of holes from the preliminary chamber (while maintaining the same cross-sectional area). Similar values of excess air coefficient during ignition of the fuel dose in the prechamber were observed, which resulted in changes in the flow between the prechamber and the main chamber. The differences in mass flow affected the temperatures achieved in the individual combustion chambers. Based on three-dimensional analyses, the mass transfer rate between the chambers and the temperature distribution were assessed during fuel ignition initiated in the prechamber.
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Bibliography

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Authors and Affiliations

Ireneusz Pielecha
1

  1. Poznan University of Technology, Faculty of Civil and Transport Engineering, Piotrowo 3, 60-965 Poznan, Poland

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