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Item type:Publication, Access status: with files , Analysis of the behavior of a linear axis with an industrial robot(Institut für Fertigungstechnik und Werkzeugmaschinen IFW, 2026-02); ; ; Industrial robots offer a variety of advantages for large-part manufacturing, e.g. the machining of vertical tail planes or wing spars, over conventional machine tools. Their compact footprint and modular design enable broad industrial applicability. However, the spherical workspace of a single articulated industrial robot may be insufficient for large parts. To overcome this limitation, industrial robots are combined with workspace extensions like linear axes. When the linear axis is interpolated with the robot joints, it enables continuous process movement, increasing production speed and flexibility. Mounting the robot on the linear axis introduces the carriage, a dynamic body with distinct properties, into the kinematic chain; consequently, as the first dynamic element, the carriage significantly influences the articulated robot and the combined system’s dynamics. Experiments on a linear axis designed for path-accurate robot processes including two rack-and-pinion drives demonstrate that the coupling effects of the linear axis and the articulated robot, as well as the dynamic properties of the combined system, are pose-dependent. The optimal integration of the external axis into the control system requires a thorough characterization of these dynamic properties. This work presents a rigid multibody model inspired by an inverse pendulum that couples the linear axis translatory with the mounted robots’ rotary axes movements at acceleration level and by trigonometric terms. The model reveals how dynamic properties of the linear axis change according to the robots pose and its multi-DOF stiffness and damping properties. This enables the optimization of control system parameters and the narrowing of filter bandwidths. An approach for industrial controller tuning based on the introduced model is presented. Implementation focuses on the linear axis within the industrial controller, with improvements validated through path measurement of the tool center point of the robot.Publicationtype: Conference Paper25 4 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Model based assessment of maximal surface temperatures and heat flow in edge trimming of UD CFRP with tools of different type(Elsevier, 2025-04-04); ; ; ; Excessive heating during edge trimming of CFRP components leads to matrix degradation impairing their quality. The thermal response of unidirectional CFRP when machining with different tool types is studied: PCD cutters, coated carbide routers, and diamond grinding pins. Temperature and torque were measured at various fibre orientation angles Φ and cutting conditions. Based on an analytical model, key thermal parameters were identified from experimental data. For all tools, temperatures exceeded the matrix glass transition temperature under most conditions. Maximum of temperature changes was observed at Φ = 135°, minimum at Φ = 90° was most pronounced for the cutter, less noticeable for the router, and almost absent for the grinding pin. At Φ = 90°, the thermal contact length and heat flow ratio typically reached maximum values, while the heat flux was at its lowest. Regarding cutting conditions for both the cutter and router, an increase in cutting speed led to higher equivalent heat flux, heat flow, and temperature change. In contrast, for grinding pins, temperature change increased at the lower cutting speed or feed rate. In grinding, heat flow, equivalent heat flux and thermal contact length were primarily influenced by the fibre orientation symmetry angle, whereas heat flow and equivalent heat flux were nearly independent of the cutting conditions. Thus, the tool types exhibit different thermal parameters and patterns of their dependencies on the machining conditions, which are differentiated by the model and can be explained by pulsed point, pulsed linear or continuous surface contact of individual cutting edges.Publicationtype: Journal Article38 32 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , The role of material properties in modeling maximal surface temperatures and heat distribution in milling of UD CFRP(Elsevier, 2025); ; ; ; In order to meet the precision requirements for components made of carbon fibre reinforced plastics (CFRP), the edges are often trimmed by milling. However, this can lead to detrimental thermal damage to the machined surface. The aim of the study was to investigate in detail the maximum temperatures and characteristic thermal parameters for various unidirectional CFRP materials under different cutting conditions. During upcut milling using a PCD cutter an infrared camera, thermocouples and a dynamometer were employed to monitor temperatures and the cutting power. An analytical heat flow model suitable for arbitrary fibre orientation angles was used to determine, based on thermal material properties, the temperature change at the machined surface and the heat flow parameters from experiments. Material influence on the cutting power was considered by its specific elastic energy at fracture depending on the volume content and mechanical properties of the fibres. At the machined surface, the resin glass transition temperatures were frequently exceeded, and the highest temperature changes were observed at a fibre orientation angle of Φ = 135◦. In most cases, higher cutting speeds were accompanied by greater temperature changes. Phenomenological models of the thermal parameters of the machining process were developed, which take into account both the thermal and mechanical CFRP properties and show a good correlation with the experimental results. They provide benefits in order to predict the temperature fields for materials with differing properties and under varying cutting conditions.Publicationtype: Review Article44 11 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Modeling of temperature fields in milling of unidirectionally reinforced CFRP depending on the fibre orientation angle and the effective width of cut(Elsevier, 2025); ; ; ; CFRP parts are conventionally used within various industries; however, during machining these components, the generated heat is a very relevant limiting factor. Exceeding the glass transition temperature can lead to workpiece degradation, reduced strength, and shorter lifetime. During up-cut milling of unidirectional (UD) CFRP with PCD cutters, the temperature was measured using thermocouples and a thermographic camera, while the cutting torque was measured with a rotating dynamometer. The maximum temperature increase at the machined surface, the heat flow from the machining zone into the material, and the ratio of heat flow to cutting power were simulated. An analytical model developed earlier for the temperature field in machining orthotropic composites with arbitrary fibre orientation was used. The results indicate that cutting power, heat flow, and the ratio of heat flow to cutting power exhibit approximate symmetry relative to the fibre orientation angle Φ = 90°. Introducing the concept of the fibre orientation symmetry angle is useful. Unexpected fractures of larger segments of remaining UD CFRP material occur at all feeds at higher fibre orientation and engagement angles within a small range of fibre cutting angles near 45°, significantly reducing the nominal width of cut and impairing results. The effective width of cut was evaluated based on the drop in cutting torque, measured at various fibre orientation angles, cutting speeds, feeds, and nominal widths of cut. The highest maximum temperature increase consistently occurs at Φ = 135°. As an overall effect, higher cutting speeds lead to increased cutting power, heat flow, and maximum temperature at the machined surface, but result in a smaller depth of the heat-affected zone. The simulations conclude that a higher fibre orientation symmetry angle leads to a higher equivalent heat flux, shorter thermal contact length, and reduced heat flow, and vice versa. In the future, the influence of different tools and composite materials needs to be investigated.Publicationtype: Conference Paper53 14 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Synthetic data generation procedures for domain-specific environments in manufacturingSynthetic data is being used lately for training deep neural networks in computer vision applications such as object detection, object segmentation and 6D object pose estimation. Domain randomization hereby plays an important role in reducing the simulation to reality gap. However, this generalization might not always be effective in specialized domains like manufacturing that involve complex assemblies. Individual parts are integrated in much larger assemblies making them indistinguishable from their counterparts. Moreover, individual parts are often partially occluded in the scene. These situations give rise to wrong detections. Target domain knowledge is vital in these cases and if conceived effectively while generating synthetic data, can show a considerable improvement in bridging the simulation to reality gap. This paper validates synthetic data generation procedures through practical experimentation ensuring that experiments are both comprehensive and reproducible. After combining domain randomization and domain adaptation procedures for parts and assemblies used in manufacturing the model performance improves by up to 15% than the state-of-the-art domain randomization techniques. Reducing the simulation to reality gap in this way can unlock the true potential of robot-assisted production using artificial intelligence.Publicationtype: Conference Paper37 17 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , An Intelligent Pipeline for Localization of Industrial Components in Robotic Manufacturing ApplicationsThe rising skill shortage problem in Europe threatens the economic slowdown in the manufacturing sector. Approaches based on artificial intelligence can play a crucial role in bridging the shortage gap if they can be integrated into robot-assisted production to simplify repetitive manual tasks. Localizing components in a production cell is a familiar problem of robot-assisted production. Robots are often taught trajectories manually, which requires expertise in robot programming. Some of the existing feature-based computer vision solutions can localize a component in 3D space. However, these solutions are not versatile enough to be integrated across different components and production cells. This paper proposes an AI-based solution in the form of a pipeline for the 6D localization of components that can be integrated into multiple industrial use cases. The pipeline encompasses flows for generating synthetic images of components from their CAD model, training deep neural networks to estimate component poses, and improving their accuracy for manufacturing applications. The performance of the pipeline has been validated for components in a production-related environment. The paper also demonstrates the versatility of the pipeline by deploying it for a robotic spray coating use case. Such AI skills can empower the skilled workforce on the shop floor so that they can focus on the overall manufacturing process.Publicationtype: Conference Paper42 41 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Influence of spatial engagement angles on machining forces and surface roughness in turning of unidirectional CFRPCarbon fibre-reinforced polymer (CFRP) is being widely used due to its low specific weight and outstanding mechanical properties. However, using identical machining parameters on unidirectional CFRP can lead to different results depending on the fibre orientation. Recently, a process-independent model describing the engagement conditions in oblique cutting of unidirectional CFRP has been developed, introducing the spatial angles θ0 and φ0 . Since the engagement conditions of milling and drilling are complex, analogy experiments are conducted in turning with variation of the setting κr and inclination angles λs . In this study, process forces and surface roughness were measured as a function of the complete range of fibre cutting angle θ.Publicationtype: Journal Article45 114 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Prediction of surface profile in CFRP machining through phenomenological analysis and inverse continuous wavelet transformationCarbon fibre-reinforced polymer (CFRP) is favored for its high strength to weight ratio, outstanding direction dependent mechanical properties and the high potential for load adapted design. However, machining unidirectional CFRP is challenging due to its anisotropic behavior, resulting in variable surface quality under identical machining parameters with different fibre orientations. Recently, a universal, process-independent model describing the engagement conditions in oblique cutting of unidirectional CFRPs has been developed, introducing the spatial fibre cutting angle θ0 and the spatial engagement angle ϕ0. Milling and drilling are mostly used for machining CFRP. Since the engagement conditions are rather complex, first analogy experiments are conducted in turning with variation of the setting and inclination angles. In this study, continuous surface profiles were recorded as a function of the spatial fibre cutting angle. Phenomenological and continuous wavelet analyses can be used to describe the surface profiles as a function of the spatial engagement conditions and to accurately predict them and the surface roughness using an inverse wavelet transformation. Experimental investigations with a side milling process of CFRP validate the prediction approach and show a good agreement between the experimental and predicted surface profiles.Publicationtype: Conference Paper22 75 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Prediction of surface profile in CFRP machiningCarbon fibre-reinforced polymer (CFRP) is favored for its high strength to weight ratio, outstanding direction dependent mechanical properties and the high potential for load adapted design. However, machining unidirectional CFRP is challenging due to its anisotropic behavior, resulting in variable surface quality under identical machining parameters with different fibre orientations. Recently, a universal, process-independent model describing the engagement conditions in oblique cutting of unidirectional CFRPs has been developed, introducing the spatial fibre cutting angle 𝜃₀ and the spatial engagement angle 𝜙₀. Milling and drilling are mostly used for machining CFRP. Since the engagement conditions are rather complex, first analogy experiments are conducted in turning with variation of the setting and inclination angles. In this study, continuous surface profiles were recorded as a function of the spatial fibre cutting angle. Phenomenological and continuous wavelet analyses can be used to describe the surface profiles as a function of the spatial engagement conditions and to accurately predict them and the surface roughness using an inverse wavelet transformation. Experimental investigations with a side milling process of CFRP validate the prediction approach and show a good agreement between the experimental and predicted surface profiles.Publicationtype: Conference Presentation20 17 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Kraftmodellierung beim Schleifen von UD-CFK unter räumlichen Eingriffsbedingungen(2024); ; Endlosfaserverstärkte Faser-Kunststoff-Verbunde (FKV) spielen für Anwendungen im Leichtbau eine herausragende Rolle. Der orthotrope Aufbau dieser Werkstoffgruppe bedingt jedoch ein richtungsabhängiges Trennverhalten. Bei der spanenden Bearbeitung führt dies unter anderem zu einer Variation der Zerspankräfte im Eingriffsbereich des Werkzeugs bei ansonsten konstanten Zerspanbedingungen. In der Kraftmodellierung wird diesem Umstand üblicherweise durch die Berücksichtigung des Fasertrennwinkels θ Rechnung getragen. Der Winkel θ entspricht dabei dem eingeschlossenen Winkel zwischen der Schnittrichtung und Faserlängsrichtung innerhalb der Laminatebene des FKV. Allerdings ist der Winkel nur beim Besäumen mit Schaftwerkzeugen für eine vollständige Beschreibung der Eingriffsverhältnisse ausreichend. Bei einer Vielzahl weiterer, spanender Bearbeitungsprozesse wie dem Bohren, Kreissägen, Trennschleifen mit Trennscheibe oder dem Oberflächenschleifen lassen sich die Eingriffsverhältnisse und das Trennverhalten hingegen nicht mit nur einem Winkel beschreiben. Zur vollständigen Beschreibung und Modellierung beliebiger Eingriffsverhältnisse wurden daher der räumliche Fasertrennwinkel θ0 und der räumliche Eingriffswinkel φ0 eingeführt. Dabei entspricht der Winkel θ0 dem eingeschlossenen Winkel zwischen der Schnittrichtung und der Faserlängsrichtung und der Winkel φ0 dem eingeschlossenen Winkel zwischen der Schneidenebenennormalen und der Faserlängsrichtung. Anhand systematischer Schleifversuche an UD-CFK wird in diesem Beitrag aufgezeigt, welchen Einfluss die Variation der Winkel auf die Kräfte beim Schleifen besitzt. Aufbauend wird erstmals ein mechanistisches Kraftmodell entwickelt, welches die Berechnung der Schleifkräfte bei beliebigen räumlichen Eingriffsbedingungen ermöglicht. Die Validierung des Modells erfolgt abschließend anhand eines Trennschleifprozesses mit komplexer Werkzeuggeometrie und Prozesskinematik.Publicationtype: Conference Paper52 343