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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 Article40 34 - 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 Paper55 20 - 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 Article45 14