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Robotic assembly processes are integral to industrial manufacturing, traditionally relying on pre-programmed sequences that exhibit limited adaptability to uncertain conditions. Recent advancements propose AI-enhanced vision systems as viable solutions to mitigate uncertainty in automated tasks. Despite the potential of vision, contact-intensive, high-precision assembly processes need customized force-torque feedback strategies to perform the task. Parametrization for setup and adaption of force-torque processes are time consuming, but decisive for quality. This work outlines an AI-driven force-torque control strategic solution for peg-in-hole assembly task, which employs object detection algorithm to grasp the workpiece and determine flexible assembly position, with force-torque-informed DNN algorithm for error correction in terms of position, and digital twin to monitor the process and collect virtual data.

Continuous generating grinding is a highly productive and precise way to finish hardened gears. However, the dressing of the tool has a huge potential for optimization. Detecting the optimal point to stop the dressing process would save cost and reduce machine downtime. This paper provides a proof of concept of how machine learning models can achieve these goals based on acoustic emission data. Therefore, different ML-Classifiers were trained and compared. Particular emphasis was placed on the robustness of the models. In addition, the trade-off between fast and robust models was examined.

Due to the continuously growing performance of information technologies (IT), it can be observed that an increasing number of tasks can be shifted to the digital space. Such a trend is also recognizable in mechanical and plant engineering. For example, the commissioning of a real machine can be accelerated on the basis of components that have already been virtually commissioned. To achieve this, an organized database is required. This database is known as the digital twin. Its complexity is application dependent. The tasks of the digital twin range from monitoring and Human Machine Interaction (HMI) to support during commissioning and optimization. The aim of this publication is to identify methods for the systematic development of a digital twin of a Numerical Control (NC)-based production system and to present current developments for its utilization. For this purpose, a systematic analysis of scientific publications in this field will be carried out.

One of the most extensively utilized techniques for material processing is injection molding, which is used to manufacture highly accurate and complex plastic items. In order to produce qualified items and ensure quality of the products, process parameter determination is crucial. We propose and compare two approaches for intelligently determining the parameters and controlling the quality within the injection molding process while aiming towards zero defects. These approaches are combinations of the process model trained using Automated Machine Learning (AutoML) with optimization techniques based on Bayesian and genetic algorithms.

Diagonal continuous generating grinding with ceramic bonded wheels is commonly used for hard finishing of automotive gears with topological modifications. In this process, areas of the grinding wheel have to be used repeatedly to machine multiple components, resulting in not achieving the same tool life as conventional generating grinding. This paper presents a detailed process model predicting loads on the wheel as a basis for an optimization of tool life. Based on a redistribution of the roughing and shifting areas of the grinding wheel, significantly lower wear could be demonstrated in tests.

The dynamic behaviour of machine tools during cutting is investigated by Operational Modal Analysis (OMA), which overcomes the disadvantages of the Experimental Modal Analysis (EMA) using excitation methods such as shakers or hammers, not considering effects occurring during operation. The assumptions of OMA such as time-invariance and white noise excitation are difficult to fulfil considering the boundary conditions of a milling process. The results show that feed motions classify the varying dynamic behaviour in the working space and excitation is controlled by modification of the milling conditions. Modal Parameters, identified by OMA, provide process-related results enabling to improve performance.

The importance of cutting hardened materials without influencing their structural properties makes abrasive waterjet machining a favorable choice in certain applications in comparison with other manufacturing technologies. Using this technology, faulty surface structures and errors caused by high thermal loads such as burrs, burns and cracks, can be avoided. In this paper, the results of applying the abrasive waterjet technology for cutting of hardened steel and its advantageous properties in comparison with cut-off grinding will be presented. The influence of process parameters on surface properties and burr formation has been determined by experimental analysis.

The use of lightweight materials such as carbon fibre reinforced plastics (CFRP) is increasing due to the demand for rising resource and energy efficiency, especially in the aerospace and automotive industries. Because of the high delamination tendency of these materials and their abrasive impact on the tool, the challenges in machining CFRP lie primarily in the drilling process and thus in the design of the drilling tool. In this paper, an innovative design of a drilling tool for machining CFRP with force-controlled radial feed movement of the cutting edges is presented. The aim of this tool is to create a tool axial force free process that uses a force-controlled radial feed motion, which matches the chip cross-section to the wear condition of the cutting edge. The tool concept is explained based on the functionality of the actuating process. Tests were evaluated with regard to process forces and drilling quality to show that the tool is capable of producing delamination-free bores in a tool axial force free process.

During milling operation, the position of the tool centre point (TCP) is affected by structural displacements, which are caused by force loads and heat input inside the machine as well as machining induced thermal loads. These thermal loads result in considerable thermal deformations of tool holder, tool, and accordingly the TCP position. They can be summed up to about tens of microns and compromise the dimensional accuracy. The objective was to develop an integrated, numerical simulation-based approach for future TCP correction for a milling process using characteristic diagrams. For this, a complex Fluid-Structure-Interaction (FSI) simulation model predicts the uni-axial displacement in the longitudinal direction of the TCP due to a specified process heat source at the tool tip. As a partial result, the simulation has reached its performance limits, under the restriction of a reasonable simulation time in order to produce characteristic diagrams for application on a milling machine. The calculated thermally induced displacement can be further processed with the aid of Design of Experiments (DoE) and response surface methodology (RSM), depending on the thermal process load and coolant volume flow rate. That results in characteristic diagrams for the displacement as a function of process parameters. In this study the calculated value for thermally induced TCP displacement covers a span from 10 μm to 80 μm, with a strongly nonlinear behaviour. Subsequently, this forms the basis for a future implementation of characteristic diagrams in the machine control system for online correction of thermal tool errors.

Due to the symmetrical flank configuration, herringbone gears have no resulting axial forces and a smaller tooth width than helical gears. Because of existing manufacturing limitations, currently only double helical gears with wide center space or assembled herringbone gears are applied.

Additive manufactured components provide a new level of shape flexibility. However, this process has shortcomings in surface quality and dimensional accuracy. As a result post-processing is often necessary. In this paper, a combined finishing operation of machining shaping and force-controlled burnishing is used for prismatic form elements. Therefore, a corresponding control strategy was implemented for this on a CNC machine tool. The focus lies on the process characteristics between the pre-machined surface structures and the force-controlled machining and in the resulting surface properties. The aim of the work is the investigation and application of the process combination on additive manufactured metallic structural elements.

In this paper the potential of a reliable characterization of surface and subsurface properties is presented by measurement of process forces for determining the specific grinding power Pc”and the micromagnetic Barkhausen noise in cylindrical grinding trials. Therefore different dressing conditions by grinding with conventional wheel with varying process parameters are investigated. It is shown that an identified lower thermal limit in a Pc”-∆t-diagram (contact time ∆t) to prevent tempering zones in the ground surface and subsurface area of case hardened steel is applicable even if the condition of the grinding wheel is intentionally influenced by dressing. Finally a soft sensor concept for the use of the specific grinding power and in perspective also the use of the Barkhausen noise for process control is derived.

Die aktuelle VDI-Richtlinie 3106 bildet auf Basis von Berechnungsmodellen die instruktive Grundlage zur Einstellung einer sicheren Werkstückspannung mittels Dreibackenfutter. In diesem Beitrag werden die Eignung der ursprünglich für die Drehbearbeitung entwickelten Richtlinie für die Fräsbearbeitung experimentell untersucht sowie ausgewählte Einflussparameter der Spannwirkung analysiert. Die Ergebnisse zeigen den Handlungsbedarf zur Entwicklung neuartiger, angepasster Berechnungsverfahren auf.

In optimising the cutting of carbon fibre reinforced plastics (CFRP), increasing emphasis is placed on the cutting edge microgeometry. A significant challenge lies in understanding the engagement conditions between tool and workpiece, influencing tool wear mechanisms and performance. This paper aims to provide a more in-depth insight into the influence of cutting parameters on process forces when applying ideally rounded cutting edges in orthogonal cutting. A geometric empirical process model is developed for calculating the cutting force and the passive force, considering the cutting edge radius, the uncut chip thickness, and the fibre cutting angle. As a result, the minimum uncut chip thickness was determined, and process forces were calculated.

Hard machining of brittle materials such as ceramics is a process-oriented challenge. For the machining of such materials, abrasive water jet cutting is an appropriate alternative to the commonly used diamond grinding and laser cutting processes. In abrasive water jet machining the injection technology is currently used almost exclusively. Due to the realisation of the suspension jet technology a higher cutting performance can be achieved. In this article, the known injection technology and the suspension technology are compared. To do so, the influences on the quality were examined for trimming technical ceramics. The investigation illustrates that suspension technology trims with a higher accuracy than injection technology in matters of kerf geometry but with a lower material removal rate.

Burnishing as a forming finishing process enables the production of precise and mechanical compressed surfaces. The forming operation can be easily integrated into cutting processes due to its kinematic similarities. Through this integration it was possible to create highly efficient process chains for the machining of rotational symmetrical parts. The formed surface qualities are also interesting for prismatic geometries, but the adaptation of this force controlled process is challenging, because of its multiaxial characteristics. A main limiting factor for burnishing on plain surfaces is the formation of a burnishing bulge on the edges of the burnished area. Several investigations of the process on plain surfaces where done to analyse the bulge formation characteristics of the aluminium EN AW-2007 material. Experiments of different single burnished paths and burnished areas with the subsequent 3D capturing of the created surfaces were done. The investigations show, that the deformation is highly dependent on the applied burnishing force and the burnishing feed. The length and width of the burnished area does not have an influence on the bulge formation.

Besonders für Materialien mit stark differenten Eigenschaften stellt das Wasserabrasivstrahlschneiden eine Alternative zu konventionellen Trennverfahren dar. Dieser Beitrag stellt den Präzisionsbeschnitt von dreidimensionalen CFK-Aluminium-Verbunden mittels Feinstrahlschneiden vor. Der Fokus liegt auf der Untersuchung verschiedener Schneidstrategien und deren Einfluss auf die Eigenschaften des Verbundes. Es wird gezeigt, dass Düsenführung und Parameterwahl entscheidend für die Bauteilqualität sind.

Basierend auf einem geometrischen Prozessmodell des orthogonalen Hochgenauigkeitsdrehfräsens wird in diesem Beitrag eine Werkzeugkonzeption vorgestellt, die eine Fertigung von Mantelflächen höchster Güte an rotationssymmetrischen Bauteilen ermöglicht. Die einstellbaren Werkzeuge werden bei diesem Verfahren speziell auf die Werkstückgeometrie unter Beachtung der Prozessdynamik und des Werkzeugverschleißes angepasst. Ziel ist die Substitution von Rundschleifprozessen durch exzentrisch-orthogonales Drehfräsen und damit die Erweiterung der Komplettbearbeitung von Bauteilen auf Dreh-Fräsbearbeitungszentren.

Das in diesem Beitrag vorgestellte Prozessmodell zum orthogonalen Drehfräsen ermöglicht einen bedeutenden Sprung in der umsetzbaren Genauigkeit bei der Fertigung von rotationssymmetrischen Werkstücken wie zum Beispiel hydrodynamisch geschmierte Haupt- und Pleuellagersitze einer Kurbelwelle. Durch die Lokalisierung des Spanprozesses auf die Stirnschneide des Fräswerkzeugs können die Eingriffsverhältnisse und die auftretenden Prozesskräfte exakt bestimmt und prozessspezifische Werkzeuggeometrien rechnerisch aus dem Modell abgeleitet werden. Das Ziel dieser Entwicklung ist die Substitution von Rundschleifprozessen durch exzentrisch-orthogonales Drehfräsen, das durch die Komplettbearbeitung in Dreh-Fräsbearbeitungszentren hohe ökonomische und ökologische Vorteile beinhaltet.

Cut-off grinding is an applied machining technology to separate high strength steel bars. Due to the high heat generation and geometrical boundary conditions, diverse thermally induced defects occur in the machined part, for example grinding burn and burr formation. Based on FE analysis, the heat distribution inside the steel bar was calculated for different cutting conditions with the goal of minimizing these manufacturing errors. The critical maximum workpiece temperature decreases up to forty-eight percent by adapting the cutting parameters and cooling strategy. The numerical model and calculated temperature distributions were verified via experimental analysis.

Granulators are widely used to reduce reinforced and unreinforced plastic strands in small pieces. The tools implemented in this machining process are mainly made of high-speed steel. This work investigates diverse PVD hard thin coatings with the aim of improving tool life and efficiency in granulation technology. A test facility reproducing the main features of a real granulator has been designed and assembled. The machined strand materials are ABS plastic and fibreglass-reinforced polyamide 6, while the tested PVD films are CrN, TiCN, TiAlN and two different diamond-like carbon coatings. The wear evaluation of all coated tools has been done via structured light projection, together with a scanning electron microscopy-based analysis, before and after their implementation on the test facility. Furthermore, a suitable 2D finite element modelling of the machining process has been realized.

Granulators cut extruded elastomer wires in small pieces, which can be used as starting raw material for injection molding. This contribution investigates the most relevant parameters of process and tool geometry for the granulation technology, with the aim of improving process efficiency and granule quality. Fiber-reinforced PA and ABS plastics have been analyzed using a dedicated test bench and finite element simulations. High-speed camera and various sensors were used to investigate the cutting process. The considered geometrical and kinematic parameters have been varied within a broad range in order to determine optimum values.

Laser Assisted Milling (LAM) is a hybrid machining technology which combines conventional milling with a localized laser beam. The laser spot heats the uncut workpiece material in front of the cutting edge. The aim of this technology is to improve the machinability of difficult to cut alloys, like Inconel 718. Hence, the material strength is reduced by high temperatures in the hot cutting process. Indeed, Inconel 718 is widely used in aerospace industry due to its excellent mechanical strength and corrosion resistance at high temperatures. These properties result in poor machinability and high tool wear. In this paper experiments of LAM and conventional milling of Inconel 718 were performed by using ceramic inserts. Methods from the Design of Experiment (DoE) were adopted in order to investigate the influence of laser and milling parameters in the hybrid process. The response variables were measured as tool wear, tool deflection, active machining force Faand passive force Fp. The results showed that machining forces, tool deflection and also tool wear could be reduced by laser heating, especially using enhanced cutting data.

The main goal of energy-efficient manufacturing is to generate products with maximum value-added at minimum energy consumption. To this end, in metal cutting processes, it is necessary to reduce the specific cutting energy while, at the same time, precision requirements have to be ensured. Precision is critical in metal cutting processes because they often constitute the final stages of metalworking chains. This paper presents a method for the planning of energy-efficient machining processes based on numerical simulations. It encompasses two levels of planning flexibility: process adjustment and process design. At the process adjustment level, within the constraints of existing machines and tools, numerical simulations of orthogonal cutting are used to determine cutting parameters for increased energy efficiency. In this case, the model encompasses specific cutting energy, tool wear, chip geometry, and burr shape. These factors determine the energy and resources required for the chip formation itself, tool replacements, cleaning and deburring and with that the overall energy efficiency and precision. In the context of process design, with the ability to select machines, machine configurations, tools, and cooling systems, numerical simulations of cutting processes that incorporate machine and tool conditions are applied in the planning of energy-efficient machining. The method is demonstrated for the case of drilling processes and supported by experimental investigations that identify the main influences on energy efficiency in drilling.

In the next few years there is likely to be a large growth of interest in the dynamic modelling of travel behaviour. In order to try to avoid the eventual collapse of enthusiasm which has sometimes occurred with other new developments when they turn out not to provide transport planning with the hoped-for panacea, this paper aims to demonstrate the diversity of approaches which will be required to tackle the subject of dynamics. In particular, it identifies three overlapping but distinct levels at which dynamics interact with travel behaviour — microdynamics, which is concerned with the detailed scheduling of activities and travel within a day — macrodynamic modifiers, whereby changes in medium- and long-term behaviour which are often considered to be instantaneous are in fact subject to important phasing considerations — and macrodynamic processes, which deal with the overriding demographic processes of birth, ageing and death. The paper suggests approaches to the incorporation of these three topics into the forecasting of travel behaviour.

Transportation study home interview surveys normally underestimate the amount of trip-making by residents of a study area, and the data has to be adjusted subsequently to compensate for this effect. One important reason for the shortfall appears to be the incomplete recall and reporting of travel information by respondents. The paper examines the influence of the survey instrument on recall by comparing reported travel behaviour in two surveys conducted in the same town, one using a conventional travel diary and the other an activity diary. The latter format appears to encourage a more complete response, giving rise to significantly higher reported trip rates and travel times. The paper discusses some research and policy implications of this finding and concludes with tentative suggestions for improved travel survey instruments.

Die Herstellung von Elastomerbauteilen mit urformenden Fertigungsverfahren ist auf Grund der kostenintensiven Herstellung des notwendigen Presswerkzeugs besonders bei Kleinserien oder Einzelteilen unwirtschaftlich. Als eine Alternative wird daher die flexible spanende Bearbeitung angesehen. Die weichen Elastomere lassen sich jedoch nur sehr schwierig bearbeiten, da das Material der Schneide ausweicht und somit keine definierten Strukturen herstellbar sind. Im Rahmen dieses Beitrags wird eine neuartige Technologie vorgestellt, welche mit kryogener Kühlung die mechanischen Eigenschaften des Elastomers temporär anpasst, wodurch diese deutlich steifer und härter werden, und somit eine präzise spanende Bearbeitung ermöglicht wird. Die Versuchsergebnisse zeigen, dass filigranste Formelemente mit einer sehr hohen Genauigkeit und Oberflächenqualität fertigbar sind.

Many nations responded to the corona virus disease‐2019 (COVID‐19) pandemic by restricting travel and other activities during 2020, resulting in temporarily reduced emissions of CO2, other greenhouse gases and ozone and aerosol precursors. We present the initial results from a coordinated Intercomparison, CovidMIP, of Earth system model simulations which assess the impact on climate of these emissions reductions. 12 models performed multiple initial‐condition ensembles to produce over 300 simulations spanning both initial condition and model structural uncertainty. We find model consensus on reduced aerosol amounts (particularly over southern and eastern Asia) and associated increases in surface shortwave radiation levels. However, any impact on near‐surface temperature or rainfall during 2020–2024 is extremely small and is not detectable in this initial analysis. Regional analyses on a finer scale, and closer attention to extremes (especially linked to changes in atmospheric composition and air quality) are required to test the impact of COVID‐19‐related emission reductions on near‐term climate. Many nations responded to the COVID‐19 pandemic by restricting travel and other activities during 2020. This caused a temporary reduction in emissions of CO2 and other pollutants. We compare results from twelve Earth system models to see if the emissions reductions affected climate. These twelve models performed over 300 experiments using multiple initial‐conditions. We find a consensus that aerosol amounts were reduced, especially over southern and eastern Asia, during 2020‐2024. This led to increases in solar radiation reaching the surface in this region. However, we could not detect any associated impact on temperature or rainfall. We recommend more analyses on regional scales. We also suggest that analysis of extreme weather and air quality would be useful to test the impact on climate of emission reductions due to COVID‐19. Lockdown restrictions during COVID‐19 have reduced emissions of aerosols and greenhouse gases12 CMIP6 Earth system models have performed coordinated experiments to assess the impact of this on climateAerosol amounts are reduced over southern and eastern Asia but there is no detectable change in annually averaged temperature or precipitation Lockdown restrictions during COVID‐19 have reduced emissions of aerosols and greenhouse gases 12 CMIP6 Earth system models have performed coordinated experiments to assess the impact of this on climate Aerosol amounts are reduced over southern and eastern Asia but there is no detectable change in annually averaged temperature or precipitation