Journal: Procedia CIRP

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Elsevier

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ISSN

2212-8271

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2012 - 2019802020 - 202540
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Publications 1 - 10 of 120
  • Study on the effect of wear models in tool wear simulation using hybrid SPH-FEM method
    Item type: Conference Paper
    Zhang, Nanyuan; Klippel, Hagen; Kneubühler, Fabian; et al. (2023)
    Procedia CIRP ~ 19th CIRP Conference on Modeling of Machining Operations
    The prediction of the tool wear progression using numerical methods has been widely studied in recent years, and various wear models considering different wear mechanisms have been implemented in the simulation work. Typically, these wear models take the physical fields such as contact pressure, sliding velocity and temperature at the tool-workpiece interface into account and are applied either individually or in combinations into the wear simulation. However, how and to what extent the physical parameters in these models affect the generated wear profiles have not been explored in detail in the simulation. In this paper, the behaviors of several typical wear models are studied by simulating the tool wear of cutting Ti6Al4V using a hybrid SPH-FEM method. Considering different combinations of physical contact parameters in the wear model, the simulated wear progression is discussed, and the resulting worn tool geometry is qualitatively compared to the experimental result. Furthermore, insights into the calibration of wear models are proposed.
  • Cutting fluid influence on thermal behavior of 5-axis machine tools
    Item type: Conference Paper
    Mayr, Josef; Gebhardt, Michael; Massow, Benjamin B.; et al. (2014)
    Procedia CIRP ~ 6th CIRP International Conference on High Performance Cutting, HPC2014
    Thermally induced errors on machine tools are one of the most important error sources in precision machining. Up to 75% of the overall geometrical errors on workpieces are caused by thermal errors of the machine tool [1]. The work presented in this paper deals with the differences in the thermal behavior of machine tools for dry or wet cutting. It is shown, that the thermal error is enlarged on the machine tool under investigation with cutting fluid. Large differences can also be seen if the cutting fluid is used for a dynamic changing load case. Here, the cutting fluid has a “damping” effect on certain thermal resonance frequency of the machine tool. It is discussed how cutting fluid is influencing the chosen machining strategies for precise workpieces.
  • Design Library Solution Patterns in SysML for Concept Design and Simulation
    Item type: Conference Paper
    Kruse, Benjamin; Shea, Kristina (2016)
    Procedia CIRP ~ 26th CIRP Design Conference
    Object-oriented models in the Systems Modeling Language (SysML) are developed in this paper to support the concept development phase within engineering design. Generic libraries in SysML for functions, according to the functional basis, and structural components, are presented in previous work by the authors. This paper extends this work and proposes the use of multi-solution patterns in SysML that combine a new behavior simulation library together with the previous generic libraries describing functions and components. These patterns capture coherent solutions to known problems that can be reused in concept design with the aim to save modeling effort. Since they are based on solution-neutral functions, they also offer multiple potential solutions at once. The new behavior simulation library and solution patterns are demonstrated in this paper using a 3D printer case study with two different kinematic solutions.
  • Conceptualising Ideation Workshops for SMEs
    Item type: Conference Paper
    Heck, Johannes; Steinert, Martin; Meboldt, Mirko (2015)
    Procedia CIRP ~ CIRP 25th Design Conference Innovative Product Creation
    An external ideation space seems to be a promising way to support SMEs in ideating new products and services. This paper addresses the question ‘how to operationalize important working principles in the fuzzy front end of product development for ideation workshops with SMEs, aiming at ideating new products and services?’ Based on the principles of user-centred design, iterative prototyping, as well as the SMEs’ need to take home the workshop outcome, we propose an ideation workshop concept, apply the concept in four workshops with different companies, and analyse it by triangulation of protocols, recordings, and interviews with the SMEs’ CEOs.
  • Considering Part Orientation in Design for Additive Manufacturing
    Item type: Conference Paper
    Leutenecker, Bastian; Klahn, Christoph; Meboldt, Mirko (2016)
    Procedia CIRP ~ 26th CIRP Design Conference
    Additive Manufacturing (AM) is established not only in prototyping, but also in serial production of end-use products. To use the full potential of the production technology the restrictions of current additive manufacturing processes (like support structures in Selective Laser Melting) must be considered in the design process. Especially the compliance with design rules from early design stages on is important in AM serial production, due to production quantities and the resulting scale effect. The part orientation in the build space has a strong influence on many quality characteristics. In order to use the full potential and to consider the restrictions from the start, a design guideline is necessary to support the whole design process. For this purpose, this paper presents a framework for design guidelines. The framework distinguishes between process characteristics, design principles and design rules; each supporting the designer during different stages of the design process. Furthermore, the paper examines the influence of part orientation in existing design rules and elaborates its importance. Based on this result, the design principle “early determination of part orientation” is presented, which includes a process for determining the part orientation in early stage of the design process. In addition, a design process for additive manufactured parts is demonstrated on an extensive showcase, following the guideline framework and including the principle for early determination of part orientation. The presented framework proved to be helpful in the design process and will be used in the future to collect more process characteristics, design principles and rules.
  • Building Blocks for Volume-oriented Changeability of Assets in Production Plants
    Item type: Conference Paper
    Rippel, Manuel; Schmiester, Johannes; Wandfluh, Matthias; et al. (2016)
    Procedia CIRP ~ Research and Innovation in Manufacturing: Key Enabling Technologies for the Factories of the Future - Proceedings of the 48th CIRP Conference on Manufacturing Systems
    Demand volatility and uncertainty in the business environment lead to an increasing relevance of volume-oriented changeability (VoC) for manufacturing companies. Strategic investment decisions are often based on forecasts and predictions, which more frequently fail to materialize due to obsolete assumptions or unpredictable events with extreme impact. If the production output fluctuates, fixed costs of production plants emerging from these investments result in high variance of unit costs, which has an impact on operational performance. Despite these demand and investment risks, managers on the strategic level must make capacity decisions without endangering the plant's performance both in growth and decline phases. Therefore, the paper conceptualizes building blocks for strategizing VoC of assets in production plants. These building blocks systemize capacity strategies for economical and dynamical up- and downscaling of production output. The paper depicts the impact on financial targets and analyzes contextual requirements and interdependencies with the organizational concept. By means of this decision support concept, managers of the production plant can select and combine interdisciplinary measures for developing an asset management strategy in the face of demand volatility and uncertainty.
  • Condition monitoring system for machine tool auxiliaries
    Item type: Conference Paper
    Gittler, Thomas; Stoop, Fabian; Kryscio, David; et al. (2020)
    Procedia CIRP ~ 13th CIRP Conference on Intelligent Computation in Manufacturing Engineering
    Failures on machine tools not only occur on main components, but also on auxiliaries like cooling units or oil mist separators, which causes productivity losses similar to failures on main machine components. Due to their separation from the machine’s control network, their health status is in most cases not monitored. In this study, a new approach for online condition monitoring of auxiliary units by the example of an oil mist separator connected to a 5-axis machine tool is presented. The data is analyzed via machine learning principles in order to deduct an adequate condition assessment, encompassing environmental influences.
  • Design of a Test Stand for Lifetime Assessment of Flat Belts in Power Transmission
    Item type: Conference Paper
    Urundolil Kumaran, Varun; Zogg, Markus; Weiss, Lukas; et al. (2020)
    Procedia CIRP ~ Enhancing Design Through the 4th Industrial Revolution Thinking
    Flat belts are machine elements used for the power transmission between rotating elements. Compared to chain or gear drives, belt drives express advantages such as low-noise, and shock- and vibration-damping characteristics. Additionally, the simple, low maintenance and cost effective setup as well as high energy efficiency up to 98 % make them an attractive choice. Since they transfer power based on friction, they are subject to wear and consequently are expendable parts. Hence, there is a demand to increase the service lifetime of power transmission flat belts to decrease cost and downtime due to belt failure. This requires a deeper understanding on the fundamental transmission mechanics of flat belts as well as the failure mechanism limiting their lifetime. Experimental investigation is key in achieving both goals. Existing test stands are not able to replicate high performance applications and accelerating the lifetime assessment of flat belts due to limited capabilities in belt force and speed. Therefore, in this work an innovative test stand was designed and build, with a maximum belt tension of 1500 N and a maximum belt speed of 50 m/s, enabling the transfer of 75 kW. The design of the test stand was governed by modularity regarding multiple aspects. First, a variety and range of reproducible adjustable parameters were required. Second, the test stand had to be flexible regarding the emulation of possible drive configurations. Lastly, auxiliary instrumentation had to be accommodated by the test stand and its data acquisition system. The solution concepts for specific components were evaluated using morphological analysis.
  • Developing energy estimation model based on Sustainability KPI of machine tools
    Item type: Conference Paper
    Um, Jumyung; Gontarz, Adam; Stroud, Ian (2015)
    Procedia CIRP ~ 12th Global Conference on Sustainable Manufacturing – Emerging Potentials
    Since eco-efficiency of manufacturing resource has been emphasized, various sensors to measure energy consumption have been developed and machine tool builders also provide data of energy consumption of their own products. Due to the variety and complexity of machine tools, however, an enormous amount of data is generated and can lead to uncertainties in further interpretation. The data relating to energy consumption can be classified into process parameters and machine specifications. In order to estimate the energy use that a new machine tool utilizes, the relationship with various performance indicators of the machine tool and a process plan should be examined. The challenge is how to link the machine specifications and process plan in order to obtain actual energy consumption. This paper proposes an approach for deriving an energy estimation model from general key performance indicators of the sustainability of machine tools. For the detailed application, the proposed methodology is applied to the laser welding process of an automotive assembly line and the milling process of an aircraft part manufacturer. The paper describes the methodology for finding the parameters necessary for calculating energy use and to develop the energy estimation model by utilizing experimental data.
  • Resource Consumption Monitoring in Manufacturing Environments
    Item type: Conference Paper
    Gontarz, Adam M.; Hampl, David; Weiss, Lukas; et al. (2015)
    Procedia CIRP ~ 12th Global Conference on Sustainable Manufacturing – Emerging Potentials
    Resource consumption measurement, analysis, and improvement in the context of sustainability in manufacturing reveal extensive fields of research and have become important in order to fulfil multiple requirements in ecological, economic and legislative activities. Solutions for energy consumption measurement in manufacturing are known but rarely implemented due to several reasons such as high costs, implementation complexity or unknown information. Despite the availability of several standards and guidelines towards environmental performance evaluation and optimization as well as punctual energy measurements for production systems, a user-oriented monitoring system to gather the relevant data in an efficient way has not been formulated yet. The following paper introduces a condign monitoring strategy and architecture that fills this gap and fulfils the requirements of accuracy within an acceptable cost-to-information ratio. A combination of internal sensors, external sensors and simulation provides comprehensive information of the monitored manufacturing system according to ISO 14955 and ISO 50001 standards. The implementation is verified within an industrial case study and meets the industrial needs in line with the current legislation. Further, the revealed information enables users to apply micro and macro-optimization activities.
Publications 1 - 10 of 120