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Once on Mars, maintenance and repair will be crucial for humans as supply chains including Earth and Mars will be very complex. Consequently, the raw material available on Mars must be processed and used. Factors such as the energy available for material production play just as important a role as the quality of the material that can be produced and the quality of its surface. To develop and technically implement a process chain that meets the challenge of producing spare parts from oxygen-reduced Mars regolith, this paper addresses the issue of low-energy handling. Expected statistically distributed high roughnesses of sintered regolith analogs are approximated in this work by parameter variation in the PBF-LB/M process. For low-energy handling, a dry-adhesive microstructure is used. Investigations are carried out to determine the extent to which the rough surface resulting from the manufacturing process can be smoothed by deep-rolling in such a way that the microstructure adheres and enables samples to be transported. For the investigated AlSi10Mg samples (12 mm × 12 mm × 10 mm), the surface roughness varies in a wide range from Sa 7.7 µm to Sa 64 µm after the additive manufacturing process, and pull-off stresses of up to 6.99 N/cm2 could be realized after deep-rolling. This represents an increase in pull-off stresses by a factor of 392.94 compared to the pull-off stresses before deep-rolling, enabling the handling of even larger specimens. It is noteworthy that specimens with roughness values that were previously difficult to handle can be treated post-deep-rolling, indicating a potential influence of additional variables that describe roughness or ripples and are associated with the adhesion effect of the microstructure of the dry adhesive.

Fuel Cells (FC) are one of the most promising technologies for achieving the European climate targets, especially for future mobility. As part of the German government's national hydrogen strategy, measures for the further development and implementation of FC technology as a drive technology in automobiles as well as the production and use of hydrogen were adopted in June 2020. For Germany to be a pioneer in the field of FC technology, the investments must be used sustainably. The objective of this paper is to introduce a sustainability strategy for FCs along the life cycle via production, energy sources, infrastructure, use as well as end-of-life. To present an overview of this existing value chain, life cycle analyses are compared and hypotheses for increasing sustainability are formulated. These serve as the basis for the development of interview forms for discussions with FC experts from research, industry, and politics. Based on the current state of the art and its optimization potential as well as the insider knowledge of the experts, a sustainability strategy for FC-powered automobiles is presented.

Virtual reality offers new opportunities in production education and training. The simulation of haptic perception is, however, still an ongoing topic of research. This paper describes the development of a simple tool replica to simulate different hand-held tools out of the production. Different attributes like shape, weight and functionality of the replica are changed during a user study with 20 participants. The task within the virtual environment contains a simple screw driving scenario. The test runs compared on the resulting sense of presence, since it has already be shown that presence has an impact on the learning success. The results show significant effects especially in the subscale of experienced realism. The greatest effects are measured with all attributes integrated. However, an additional integration of a single attribute like realistic weight or functionality does not necessary lead to a significant increasing sense of presence.

Customized production and provision of tailor-made services are common business models in globalized production. These can be found for example in materials research by means of high-throughput systems and the overhaul of spare parts. In both cases, there are warehouses and buffers with different requirements and limited capacity in the systems. The reactivity of these systems is therefore essential for a fast reaction to customer orders. An inventory reduction can improve this reactivity of the system but lowers the service level of short-term requests. This paper describes a method for reducing inventory levels through specific order classification. The presented method introduces how to differentiate service while considering customer-owned stocks. A validation of the model is achieved by comparing it to an analytic model and a simulation model. Results of the simulation study evaluates the applied order classification and customer stock.

The use of elementary production technologies allows to shift the knowledge and the effort of the design of manufacturing processes from the producers and towards the system manufacturers. Therefore, it enables urban producers that do not have complex process knowledge to implement robust and versatile process chains. This facilitates the utilization of elementary production technologies in local networks as enablers to produce components locally and to cover a large part of local needs, thereby incorporating not only technical, but also ecological, logistical and social aspects as for example sustainability, circular economy and participation. The following paper presents the concept of the elementarisation of production systems to create robust, controllable and combinable processes for urban production and through life engineering services.

The use of physical mock-ups offers the possibility to evaluate the efficiency of assembly processes in early design stages of product development. Therefore, the challenges of assembly procedures, which arise during the implementation of new large-dimension assembly groups, can be managed prematurely. Assembly training with a derivative product in an assembly workshop stimulates a knowledge exploitation of function and performance of assembly groups. The paper shows the acquisition of technical expertise from shop floor staff and knowledge from non-experts from assembly operations during the assembly workshop, by using the handling with a derivative product. These information were integrated into the implementation process of assembly planning.

Sustainable production systems are characterized by systematic order control and scheduling to increase performance. Efficient scheduling considers all restrictions that occur during order processing, to achieve high utilization. This includes safety margins for ad hoc changes and in particular the scheduling of temporarily paced sequences. After processing these orders, the organizational process is carried out with a highly flexible material flow similar to job shop production. This paper describes an algorithm for the efficient planning of temporarily paced sequences during scheduling of a high-throughput system, in order to achieve an optimal utilization in the planning phase.

For the handling of samples for material testing, a gentle grasping method is necessary. While scaling effects in the micro domain typically pose a challenge for handling, an adhesive grasping system based on an artificial microstructure can utilize the Van-der-Waals force to advantage. For the design of a dry-adhesive grasping system, it is necessary to determine a suitable releasing mechanism. Different approaches for releasing systems are identified. Based on literature research they are examined with regard to the task of handling material samples. A switchable microstructure and a peeling strategy are determined as the most suitable releasing strategies.

The interaction of human and machine in assembly, as applied in collaborative robotic systems, offers a great potential for a higher flexibility of production systems and the individualization of assembly operations. In order to make collaborative assembly systems save for workers that are not trained in programming and operating robotic systems, an applicable solution for the commissioning has to be implemented. This paper shows a novel concept for the virtual commissioning of human-robot assembly systems, using a human in the loop simulation that is connected to a physical robot simulation.

The assembly of products is often supported by jigs. Especially for large dimensional products, jigs and fixtures are used to align the components and ensure the stability of the assembly until all parts are firmly mounted. This paper describes the development of mobile, modular and adaptive assembly jigs, which are designed to support ergonomic working in the production of high-lift systems for civil aircrafts. The jig supports the workers to adapt the position and orientation of the product to the current assembly operation. The fundamentals of the development are explained and the features of a concept, called assembly wheel, are presented. The assembly wheel consists of two or more robot arms on a circular seventh axis. The robot arms hold and position the components to be assembled so that all joining spots are freely accessible to the worker. The ergonomic benefits of the concept were examined in a study using a 3D model of the jig. A demonstrator on a scale of 1:2 was set up, with which real experiments with an adaptive jig can be conducted for evaluation.

Manual assembly is typical for complex products with large-scales and low repetition rates. The assembly control is usually realized by supervisors and claims a large part of their working time. The approach for decentralized assembly control is used for relieving the supervisors and for making the assembly process more efficient. In case of stationary assembly processes, the decentralized control requires a lot of space for material supply because of the flexibility in assembly sequences. For reducing the space of the material supply area, a strategy is developed and tested in a discrete simulation model. The results verify a reduction of required floor space.

When introducing a disruptive technology such as artificial intelligence (AI) into a company, it is important to involve the employees from the beginning and to inform them comprehensively about the opportunities and risks of the technology. Traditional means of communication such as information brochures, company meetings and email circulars are not suitable for this purpose, as they only allow limited feedback and often present the workforce with a fait accompli. The KI_Cafe method presents a new kind of introduction strategy that follows an on-site learning factory concept. This includes information and discussion opportunities for all participants based on example scenarios, as well as the development and testing of a specific AI system. For this purpose, a requirements definition, system development and practical implementation of an AI-based assistance system are combined with recurring company-public experimental spaces, the KI_Cafe Learning factory. In a use case, a novel-based system for assessing the cutting edge quality of milling tools is developed and implemented for two small and medium sized enterprises. This enables an independent assess the condition of a milling tool and thus contributes to relieving the workload of the integrated tool pre-setting. During the development, all organizational levels from the machine operators to the managers will be included in order to map the individual needs of the device and to create an understanding of the AI system at an early stage. Accompanying this, various exhibits on the topic of AI and the current development status of the new measuring system will accessible in the KI_Cafe.

The combination of make-to-order and, a high range of small batch series are the daily business of small and medium-sized enterprises. Economical production of larger volumes is not advisable in all scenarios in productions characterized by job shop production. Structural dynamic production systems (SDMS) with individually as well as temporarily paced working systems are the technical encounter for product variations in small and medium-sized enterprises. This paper addresses scheduling for SDMS to reduce losses in productivity. The scheduling regulates the release of temporarily paced sequences. The simulation results show that this ensures a constant machine load until a pacing rate of 70%.

2019 CIRP Through-Life Engineering Services Conference, TESConf2019, Cleveland, Ohio, USA, 27 Oct 2019 - 29 Oct 2020; Procedia manufacturing 2020(49), 217-221 (2020). doi:10.1016/j.promfg.2020.07.022 special issue: "Proceedings of the 8th International Conference on Through-Life Engineering Services – TESConf 2019 / Edited by Robert X. Gao, Ruqiang Yan", Published by Elsevier, Amsterdam [u.a.]

The change in production towards smaller batch sizes demands a high degree of flexibility, especially in assembly. In this context, human-robot collaboration (HRC) is becoming increasingly important. The goal is not to displace the human being by the robot, but instead receiving support from it. Nevertheless, employees at all levels have to be prepared for the HRC. Trainings offered from robot manufacturers focus on robot specific operations and are not sufficient for the development of competencies for innovative and creative process planning and optimisation. Therefore, a mixed reality learning environment can be used for the implementation of such training, since real production facilities are only available to a limited extent for training purposes. In the context of the implementation of a mixed reality learning environment, the question arises as to the necessity of haptic feedback. This article presents a concept for integrating HRC in German initial and continuing vocational education and training using mixed reality.

Kurzfassung Im Sondermaschinenbau sind viele Montagen als Gruppenmontage organisiert. Durch die steigende Komplexität der Produkte bei gleichzeitiger Produktindividualisierung sind die Verantwortlichen in der Montage zunehmend nur mit der Steuerung beschäftigt. In diesem Beitrag wird ein Ansatz zur dezentralen Montagesteuerung auf die Gruppenmontage übertragen, welcher die Verantwortlichen in der Montage entlastet. Ein durchgeführter Versuch unterstützt die Annahme, dass der dezentrale Steuerungsansatz auch in einer Gruppenmontage erfolgreich angewendet werden kann.

Fast time to markets becoming increasingly important through dynamic product life cycles. An assembly planning in early project stages is necessary, which evaluates assembly procedures and the mountability. The use of derivative products offers this possibility since the simplified form can be used for examining important steps in assembly processes as well as for testing maintenance processes. In particular, the use of equipment and the arrangement of components are relevant. The division of labour between workers as well as the process planning can be examined with derivative products. The collected knowledge can be used for planning as well as for design. It supports the Design for Assembly (DFA) since effects of physical properties on the assembly process can be transferred back to the design stage. This paper describes the properties and possible applications of derivative products. In addition, it shows the use of derivative products for the development of new products and describes the advantages regarding conventional DFA methods.

Production processes with small tolerances are still challenging the industry. The increasing competitive pressure raises the necessity of economically efficient processes. Assembling parts while considering part-specific clearance enables a widening of the tolerance field by considering trend specific clusters and matching. Two or more otherwise rejected parts are assembled to one functional assembly. Assembling parts under consideration of a trend-specific clearance affect the interchangeability of the assembled parts. In the case of small tolerances and a high widening of the tolerance field a systematic identification of the number of spare parts is required. An approach for considering spare parts and therefore, the interchangeability in the concept of tolerance field widening is presented.

A modular assembly system is introduced for obtaining a high flexibility which consists of manual work stations and collaborative robot modules that can be individually arranged and connected, dependent on the actual process requirements and qualifications of workers. The modularization induces a fast adaption towards different product variants and enables personalized assistance for diversely skilled workers. The collaborative modules and manual work stations have to be both physically and virtually connected for the implementation of the system. The challenge for linking the modules is the calibration of the robot module as a function of the location of the manual work station. A vision based calibration method is implemented, using a reference object that has the same gripping planes as the assembly object. A system of infrared depth-finding cameras is used to record a reference object that is handled by the collaborative robot and to locate its coordinates by 3D-Image processing. By transferring the coordinates into a common system, existing program sequences, data for progress recognition and employee qualification can be adapted for the specific workspace, worker and assembly object in order to achieve maximum flexibility and personalization. A control program provides the interface between the robot and the infrared depth-finding camera and processes the functions of teach-in and gesture recognition. The presented paper includes the concepts of modularization and assistance, the implementation of the calibration method by 3D-Image processing and the evaluation of the system.

An assembly planning parallel to the product development allows to identify the arising assembly challenges and their resulting requirements at an early stage. However, a reliable planning of assembly for large-volume assembly groups is difficult, as the implementation of assembly for new products is characterized by recurring optimization phases until the assembly process can be considered as technically mature. During this phase, the proportion of manual activities is high and the assembly steps demand a high degree of improvisation. By using prototypes, the assembly process reliability can be increased. For this purpose, time- and cost-intensive constructions of real large-scale products are often manufactured, which correspond to the real product in their function or dimension. For the consideration of the assembly planning, only specific features of the assembly are necessary to evaluate the behavior during the handling and joining process and to provide information about the accessibility for assembly tools. A derivative product, designed systematically by using a decision matrix, offers an enormous benefit to answering function related questions in the handling of the assembly group. It requires a sufficiently high structural analogy, at the same time it demonstrates a sufficient degree of abstraction in order to evaluate assembly processes in a reduced dimension. A classification of the derivative product with regard to scale, material selection and geometry offers a possibility to select the degree of abstraction application specifically, in order to represent the assembly complexity. Based on an example of a large-volume assembly group in the aviation industry, the use of the decision matrix is demonstrated by configuring a derivate product in order to structure assembly processes and optimize the sequence of assembly, handling and ergonomics. The matrix contains different options for selected criteria, which provide an overall result to support the selection of the optimal degree of abstraction and dimension.

Material testing in high-throughput systems facilitates a fast, precise and innovative method for the identification of metals with required characteristics. This material testing setup leads to highly flexible material flow between test stations similar to job shop fabrication. Various requirement specific test plans and the occurrence of temporarily paced sequences between subsequent processes amplify the necessity of controlling the material flow to reduce idle times and increase utilization. This paper introduces a concept of controlling temporarily paced sections in highly flexible systems, which improves the productivity of the entire system.

The maintenance of large-scale products such as aeroplane engines or aeroplanes take place stationary. Due to the complexity of those products, the coordination of the workers is a large effort for the responsible people. This article presents a method for decentralised resource control in maintenance shops with stationary products. Therefore, an existing method for assembly control in a flow line is transferred to the team assembly. The decentralised control results in a growing motivation among workers and a relief of the coordination effort for the responsible persons. The released capacity can be used for further optimisation in the maintenance process.

A collaboration between human and robot can implicate many advantages for complex industrial assembly processes, especially as increased flexibility and adaptability become a key feature of production systems. The use of virtual reality (VR) systems has the potential to simulate cooperative processes in advance and to include workers and their individual behavior into the simulation. The use of VR simulations makes it possible to secure processes and reduce physical and mental barriers between human and robot. This paper presents a methodical approach for the implementation of systems for the virtual testing of collaborative assembly processes. Following the aim of replicating the assembly process with the highest possible immersion, a specific VR system is derived from an analysis of the assembly process. Core features of the system are the physical simulation of the assembly process, the integration of the robot control and a haptic feedback for the operator.

Micro systems technology is one of the key enabling technologies of the 21st century [Hes03], with increasing relevance due to a general trend towards miniaturisation in many industries. The main boosters for this trend are currently the consumer and communication electronics market and—to a lesser extent—medical technology (especially microfluidic devices, which had a market volume of approx. $2.5B in 2017 [Cle17]).

The handling of micro parts presents a challenge for the grasping mechanism. With a reduction of size, the surface shrinks by the power of two, while the volume shrinks by the third power. This results in an increasing impact of surface effects like adhesion forces compared to the gravitational force. While this effect complicates the handling of micro parts, it also allows handling principals, which are not suitable in the macro domain. A way of implementing these Effects for handling tasks is the adoption of biomimetic structures, as found on the surface of gecko or bug feet. In order to utilize this material for micro parts, a releasing strategy is needed. In this paper, strategies for releasing parts from gecko-like grippers in the macro domain are investigated and the basic principles are derived. These are investigated for their applicability for the handling of microspheres and thin foils. A grasping device is devised and the feasibility is shown in a proof of concept.

Manual assembly is typical for complex products with large-scales and low repetition rates. The assembly control is usually done by supervisors and takes up a large part of their working time. The approach for decentralized assembly control is used in the assembly planning for relieving the supervisors and for making the assembly process more efficient. Primarily, this approach is used in flow-lines and is based on bionic mutualistic networks, which coordinate the assembly tasks by using an artificial stimulus. This article presents a transfer concept of the approach of decentralized assembly control for different alternative types of assembly organization. For transferring the approach, apart from flowline production, key requirements are figured out and the existing types of organization are systemized. The results of an enhancement of the approach suggest that especially organizational types with aperiodic worker movements in combination with stationary or aperiodic motion structure of assembly objects are suitable for the decentralized assembly control. A first testing already verifies the qualification of the approach for team assembly with stationary products and aperiodic worker movements.

The digital progress monitoring of manual assembly processes at goods with huge dimensions is a challenging task. The paper presents an approach using 3D-image sensors for gesture control and progress recognition. The developed system is able to avoid time and effort consuming walks of workers between assembly objects and computer terminals. Progress recognition of assembly processes is realized by interpreting the movements of the workers’ hands and by detecting the passing of defined coordinates within the assembly and warehouse areas.

A central challenge of micro forming production is the handling of component parts. The simple transformation from macro to micro scale of the forming and handling processes is complicated due to size effects. One solution for overcoming these effects is to handle the components as linked parts as long as possible. Linked parts are manufactured in multistage processes in which every individual process generates different requirements. Therefore, arrangements have to be adopted to administrate growing amounts of data, for the documented coordination of the processes and also for a reproducible production. A practicable method is the development of product data models. Of major importance is the product data modelling based on ISO 10303, also known as Standard for the Exchange of Product Model Data (STEP). STEP offers extensive possibilities for the application-neutral and unambiguous data exchange. Using STEP a basic product data model for the micro forming technology is designed. It is focussing on the modelling of linked parts production.

Learning Factories are implemented for multiple applications offering opportunities for practical research and training. The majority of learning factories is designed for very special purposes as training of lean methods and manufacturing logistics. The bime developed and installed an adaptable Learning Factory called BERTHA that is capable to run various manual assembly scenarios typical for special-purpose machine assembly for example. The paper introduces the Learning Factory BERTHA, its current application scenarios and concepts to support participants and trainers to evaluate learning outcomes. Finally, the paper describes one sequence of a scenario and the application of evaluation concepts.

Many enterprises that use expensive capital goods outsource the process of spare parts supply and stocking to a maintenance-, repair-, and overhaul provider (MRO-provider). Because of the high value, these spare parts are stocked in repairable item systems, in which defective parts are repaired after removal from the machine and put back into stock. When setting inventory levels, the providers do not consider all of the spare parts that are stocked in the system because customers hold own stock to bridge the delivery time from the MRO-provider. As these spare parts are not property of the MRO-provider, the provider does not take them into account when planning inventory, incurring overstocking at the central depot. A model, which considers customer stock when determining depot inventory levels, is developed by extending the METRIC model with a heuristics. The heuristics calculates backorder levels according to the depot inventory levels as well as customer stock levels and allows for an inventory reduction. Using the proposed model, savings of depot inventory can be up to 100 %, while keeping the backorder level of part requests below a preset threshold.

Kurzfassung Die Herstellung kundenindividueller Produkte ist insbesondere für Anbieter komplexer Investitionsgüter ein zentraler Wettbewerbsfaktor. Aufgrund der hohen Anzahl an Kundenspezifikationen und der resultierenden Kombinationsmöglichkeiten ist eine Automatisierung von Montagebereichen in diesen Unternehmen nicht möglich. Montagetätigkeiten werden daher manuell ausgeführt. Der Koordinierung des Mitarbeitereinsatzes und des Montageablaufs kommt somit große Bedeutung zu und kann durch neue Verfahren der Ressourcenallokation realisiert werden.

For the integration of experts’ and non-experts’ knowledge from the assembly planning into the product development process, assembly workshops are used to acquire the knowledge and to transfer it back to the product development. A workshop was conducted using a 3D printed model of a large-volume assembly group from the aviation industry. For a repeatable implementation of the assembly workshops with a changeable assembly sequence, individual components and connecting segments are structurally simplified, so that a non-destructive assembly and disassembly can be ensured. By using questioning and observation methods the expertise of assemblers and laymen are documented. The findings of the workshops from the laymen and expert groups are evaluated to show the ability of the probands for transferring the assembly structure. For the laymen, the simplification of the components mainly influences this ability. The workshop provides a basic understanding of what experiences or learnings, generated during the assembly, can be considered in order to plan assembly processes. The prerequisite is that the participants can recognise the restrictions and the assembly effort of the real assembly, while using the simplified 3D printed model.

Augmented reality as a technology for programming a collaborative robot is in comparison to existing practice a more intuitive, safe and quick approach. This paper shows a novel concept for connecting a physical robot with its virtual twin, using augmented reality as a visual output and a device for interacting with the simulation model. The core of the system is a station control that contains all interfaces, sequencing logics and databases. For programming the robot, the coordinates are created by the operator by interaction and voice input in the augmented reality environment. All information is stored in a shared database which contains assembly plans and instructions for both workers and robots. A demonstration platform is presented, that allows to implement the concept of the system design for an experimental assembly station for human-robot collaboration. The work station includes a Universal Robot 5® that assists the worker in handling of objects and is operated by coordinates from the station control. A Microsoft Hololens® is used for programming the robot in an augmented reality environment which is based on the output of the physical robot and the work system simulation.

Production of complex and large-dimensioned goods in small lot sizes is a demanding task. In order to react to varying customer demand and changing product specifications assembly tasks are executed manually by skilled workers that provide an adequate level of flexibility. Although the task of controlling these assembly processes gets more complex, only little support is given to foreman and production planers in this regard. Existing procedures focus on production planning rather than control of processes. Thus, an assembly control procedure is developed that enables the integration of workers in control of paced assembly processes and a situation specific reallocation of personnel. Foreman and production planers are relieved from time consuming tasks of operational assembly control. The paper describes the approach and experimental results of its application.