This keynote paper addresses the manufacturing of high-precision components with micro-scale features, and the associated process chain considerations. Three workpiece classifications as well as a ...micro-production process chain (MPPC) model are defined. A review of capabilities and advances in micro-manufacturing technologies, metrology, and equipment demonstrates increased versatility across varied applications, while also highlighting limitations. Challenges in the development of process chains are presented using results of the MPPC program of the Collaborative Working Group on Micro-Production Engineering. Finally, a guide for machining high-precision components with micro-scale features in process chains is given with respect to machine tools, tools, technology and environmental conditions.
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•Hybrid additive manufacturing (AM) is re-defined through physical mechanisms.•Innovation via “property-mechanism-energy source-hybrid-AM process (PMEH)” system.•Data compiled from ...100 papers will be available to the community.•Data includes material/part properties, PMEH categories, and paper information.
This study defined hybrid additive manufacturing (AM) as “in-situ or series combination of an additive manufacturing process and secondary energy sources in which physical mechanisms are fundamentally altered/controlled to affect the resulting properties of material and/or part.” This definition includes in-situ secondary processes as well as process chains, and it is anchored in multi-physical mechanisms such that new hybrid-AM processes can be freely and systematically sought or invented through a systems approach epitomized by the “property – mechanism – energy source – hybrid-AM process (PMEH)” thought process. The sequence of driving forces in this framework are as such: desired material properties determine which mechanism is utilized and, in turn, the energy source to be applied, which ultimately defines the hybrid-AM process. The five unifying physical mechanisms that were identified in this study are: melt pool dynamics, microstructure development, stress state, surface evolution, and thermal gradients. Analysis of properties, mechanisms, energy sources, and processes was conducted on more than 100 papers, and the results ultimately show the effect of mechanisms on material properties. Mechanisms are further classified by energy source, which are in turn broken down by hybrid-AM process. Additionally, each mechanism was defined and reviewed in detail, highlighting the PMEH relationship for metal hybrid-AM materials. Further analysis compares reported mechanical property values for hybrid-AM processes to both AM only and wrought properties for 316 L, Alloy 718, and Titanium Gr 5. Finally, future directions of research as well as clear gaps in knowledge are identified, which includes lack of variety in utilized energy sources, lack of material diversity, process chain integration and improvement, and promising hybrid-AM processes. With the presented analysis and PMEH framework, it is determined that metal AM hybrid processes are well suited to address current problems and show promise in creating superior and versatile materials. Further growth in this field is expected to be exponential, and the developed PMEH framework will aid in framing these innovative processes.
Enterprise Systems (ES) are comprehensive off-the-shelf packages that have to be configured to suit the requirements of an organization. Most ES solutions provide reference models that describe the ...functionality and structure of the system. However, these models do not capture the potential configuration alternatives. This paper discusses the shortcomings of current reference modelling languages using Event-Driven Process Chains (EPCs) as an example. We propose Configurable EPCs (C-EPCs) as an extended reference modelling language which allows capturing the core configuration patterns. A formalization of this language as well as examples for typical configurations are provided. A program of further research including the identification of a comprehensive list of configuration patterns, deriving possible notations for reference model configurations and testing the quality of these proposed extensions in experiments and focus groups is presented.
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•Use of reversible solid oxide cell technology (rSOC) for energy storage.•Techno-economics of rSOC systems.•Power-to-X-to power concept suing different chemicals and rSOC ...technology.•Identification of potential application areas for rSOC technology.
This paper presents a mini-review in the field of energy storage using reversible solid oxide cells (rSOCs) for development of energy storage systems for the future. Such energy storage systems fall under the category of power-to-X-to power systems where excess electrical energy produced through renewables is stored in the form of chemicals and the same chemicals are used for conversion back to power. The main competitors of energy storage systems based on rSOC are pumped hydro storage, compressed air storage and batteries and it is envisioned that with better heat integration techniques, the round trip efficiency of rSOC systems can be improved to reach the target value of 80% as specified in the joint EASE-EERA report for European energy storage technology.
Shorter life cycles and volatile markets lead to a highly dynamic environment for manufacturing companies. To remain competitive, companies must change their product portfolio from standardized to ...customer-specific products. A special case of the production of personalized products is Production as a Service (PaaS). The objective of this paper is to provide a system description which enables the dynamic generation of process chains based on which means of production can carry out the required production steps of the customer’s individual product. In the context of PaaS these capabilities are described independently of the production technology which will be used for each production step to ensure the opportunity of a global optimization. The focus of this paper is the description of product, process and resource and in which way the interdependencies must be considered for the sequencing of process chains. Therefore, existing approaches in the area of PaaS and the generation of process chains are reviewed. Based on the finding, a description of product, process and resource is developed taking the interdependencies of process sequences into account. Future research should tackle the issues of matching product and resources and develop a framework to enable an automated matching.
The Quillcay catchment in the Cordillera Blanca, Peru, contains several glacial lakes, including Lakes Palcacocha (with a volume of 17 × 106 m3), Tullparaju (12 × 106 m3), and Cuchillacocha (2 × 106 ...m3). In 1941 an outburst of Lake Palcacocha, in one of the deadliest historical glacial lake outburst floods (GLOF) worldwide, destroyed large parts of the city of Huaraz, located in the lowermost part of the catchment. Since this outburst, glaciers, and glacial lakes in Quillcay catchment have undergone drastic changes, including a volume increase of Lake Palcacocha between around 1990 and 2010 by a factor of 34. In parallel, the population of Huaraz grew exponentially to more than 120,000 inhabitants nowadays, making a comprehensive assessment and mapping of GLOF hazards for the Quillcay catchment and the city of Huaraz indispensable. Here we present a scenario-based multi-source GLOF hazard mapping, applying a chain of interacting numerical models to simulate involved cascading mass movement processes. Susceptibility assessments for rock-ice avalanches and breach formation at moraine dams were used to define scenarios of different magnitudes and related probabilities, which are then simulated by corresponding mass movement models. The evaluation revealed, that (1) the three investigated lakes pose a significant GLOF hazard to the Quillcay Catchment and the city of Huaraz, (2) in some scenarios the highest hazard originates from the lake with the smallest volume (Cuchillacocha), and (3) current moraine characteristics of Lake Palcacocha cannot be compared to the situation prior and during the 1941 outburst. Results of outburst floods obtained by the RAMMS model were then converted into intensity maps and corresponding hazard levels according to national and international standards, and eventually combined into the GLOF hazard map for the entire Quillcay catchment, including the urban area of Huaraz. Besides technical aspects of such a multi-source model-based hazard mapping, special attention is also paid to approval and dissemination aspects in a complex institutional context. Finally, some general conclusions are drawn and recommendations are given, that go beyond the presented case of the Quillcay Catchment.
Since the term surface integrity was introduced in 1964 by Field and Kahles, the final processing step and its influence on the surface microstructure was heavily investigated. In particular, a lot ...of research on the surface microstructure and its connection to the functional properties of the workpiece like life time and wear resistance has been performed. However, the influence of the process chain on the final surface microstructure of the workpiece was in industrial applications most of the time not taken into account, although the former manufacturing steps do affect the final result. In this work, samples of ferrite-perlite 42CrMo4 steel (AISI 4140) were first processed by grinding with mechanical main impact (grind-strengthening) and then mechanically, thermally and thermo-mechanically treated to investigate the change in the microstructure depending on the chosen process chain. Electron backscatter diffraction (EBSD) measurements as well as backscatter electron images (BSE), secondary electron images (SE), energy dispersive spectroscopy (EDX) and transmission electron microscopy (TEM) were used to characterize the change in the surface modifications. The first applied grind-strengthening process caused a heavily deformed surface zone of ~4 µm with nano-crystalline grains and high dislocation densities in the following ~10 µm. Thermal treatment resulted in grain growth and dislocation annihilation due to static recrystallization whereas mechanical treatment either increased the dislocation density further or decreased the dislocation density by annihilation of dislocations and dislocation rearrangement. Thermo-mechanical treatment resulted in small equiaxed grains in the surface zone. Cementite lamellae of perlite grains were deformed, partly dissolved and formed spherical carbides at grain boundaries in the surface zone for all process chains including thermal treatment.
Additive manufacturing (AM) currently evolves from a prototyping process to an alternative manufacturing process for end-use parts, advancing into fabrication of low to medium product volumes. ...Moreover, increasing awareness of environmental impacts of manufacturing lead to the necessity of holistic evaluation among traditional evaluation criteria in the technical and economic domains. However, existing evaluation approaches seldom consider a complete AM process chain and are lacking a production-oriented notation which enables comparability across technologies and support in identification of improvement potentials on technical and environmental level. To address this gap, this paper highlights the way from structured data acquisition to setup of an energy value stream map (EVSM) for AM process chains in end-use part production, augmenting methods of lean manufacturing by the energy dimension. Consequently, it contributes to a holistic and transparent process chain perspective to assess AM as a manufacturing alternative. The proposed methodology is applied to a case study covering two different process chains, a first based on powder bed fusion via Multi-jet Fusion (MJF) and a second utilizing vat-photopolymerization via Continuous Liquid Interphase Printing (CLIP). While the MJF process chain’s energetical hot spot is situated in the printing process itself, the hot spot for CLIP is found in thermal post-processing, exceeding the comparably efficient printing process by magnitudes and ultimately resulting in higher energy intensity per part compared to the MJF process chain. These results highlight the necessity of a holistic evaluation method for complete AM-based process chains and their influence on the product properties. Insights may help engineers, designers and decision makers in pre-selection of suitable manufacturing strategies with a more complete view on AM process chains.
Up to now there is neither data available on how many errors can be expected in process model collections, nor is it understood why errors are introduced. In this article, we provide empirical ...evidence for these questions based on the
SAP reference model. This model collection contains about 600 process models expressed as
Event-driven Process Chains (EPCs). We translated these EPCs into YAWL models, and analyzed them using the verification tool WofYAWL. We discovered that
at least 34 of these EPCs contain errors. Moreover, we used logistic regression to show that complexity of EPCs has a significant impact on error probability.
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