Publications Search Results

Now showing 1 - 10 of 25
  • Publication
    Unidirectional coupled finite element simulation of thermoelastic TCP-displacement through milling process caused heat load
    ( 2021)
    Brier, S.
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    Regel, J.
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    Putz, M.
    ;
    Dix, M.
    The paper presents a numerical simulation of thermal induced tool displacement during milling oper-ation. An unidirectional finite element model is developed which consists of two sections. A CFX model and a thermal transient model. With the aid of CFX module, the conjugated heat transfer be-tween milling tool and coolant fluid is described. The result of these efforts is the body temperature field of the end mill cutter due to thermal load, which is the thermal fingerprint of the cutting process. Subsequently the calculated body temperature field is linked with a transient-structural module to cal-culate the resulting thermal elastic displacement of the milling cutter. The thermo-elastic displace-ment of the tool is determined by examining a pilot node at the tip of the end mill, whose displace-ment is calculated in relation to the global coordinate system of the model.
  • Publication
    Effects of different excitation mechanisms in machine tools when performing output-only modal analysis
    ( 2021)
    Berthold, J.
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    Kolouch, M.
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    Regel, J.
    ;
    Dix, M.
    Output-only Modal Analysis makes it possible to investigate the dynamic behaviour of machine tools, especially under process conditions. The differences between standstill and process state, which are important to be considered, result from process damping, gyroscopic moments of the rotating spindle, and changes in preloads and clearance in bearing and joints. Output-only Modal Analysis assumes a complete excitation of the structure by white noise characteristics. There are several mechanisms in a machine tool under process conditions that could cause a vibration response. Besides the cutting process itself, the movement of the NC-axes, as well as rotating fans of the control system and auxiliary units, can be excitation sources. This paper investigates to what extent several excitation mechanisms in machine tools fulfill the analysis assumption and in which way the identified modal parameters depend on the boundary conditions of the excitation characteristics.
  • Publication
    Cognitive clamping geometries for monitoring elastic deformation in forming machines and processes
    ( 2021)
    Kurth, R.
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    Bergmann, M.
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    Tehel, R.
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    Dix, M.
    ;
    Putz, M.
    In the context of inline monitoring and controlling of forming processes, the distribution of acting forces on tool and forming machine causing elastic deformation of the clamping surfaces provides fundamental information on the resulting part quality whereas the inline detection is still challenging. This paper presents a novel method using the T-slot geometry as a cognitive area for inline analyzing of the elastic deformation of the tool-clamping surfaces. Using a newly developed sensor device, the elastic deformation state of the T-slot geometry under process forces is detected by strain measuring of a deformation body mounted inside the T-slot. The functionality principle of the sensor device and measuring method for process monitoring are demonstrated by simulation and experiments, demonstrating the potential for process control.
  • Publication
    Geometric empirical modelling of forces influenced by the cutting edge microgeometry in orthogonal cutting of unidirectional CFRP
    ( 2021)
    Sauer, K.
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    Nowak, A.
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    Regel, J.
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    Wertheim, R.
    ;
    Dix, M.
    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.
  • Publication
    Multi-phase simulation of the liquid coolant flow around rotating cutting tool
    ( 2021)
    Topinka, L.
    ;
    Braeunig, M.
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    Regel, J.
    ;
    Putz, M.
    ;
    Dix, M.
    The heat generated during the cutting processes significantly influences the manufacturing accuracy. For many machining tasks, the use of cooling lubricant is essential to achieve the necessary cooling and lubricating effect in the cutting zone. A reduction of a coolant supply due to resource-efficient or ecological efforts has an impact on the temperature field in the cutting tool and clamping system, which affects the thermal behavior of the frame structure and can cause its thermo-elastic deformations leading to machining inaccuracies. In this paper, the multi-phase CFD model for simulation of liquid coolant flow around the cutting tool was developed. The effect of rotation of the cutting tool causing turbulences was taken into account and the simulation of coolant flow was based in Eulerian approach as a continuous flow. Furthermore, this paper considers the modification of the simulation model for thermal simulations of the influence of coolant flow on the temperature field of the cutting tool and clamping system.
  • Publication
    Analytic model of process forces for orthogonal turn-milling
    ( 2018)
    Hertel, M.
    ;
    Dix, M.
    ;
    Putz, M.
    The manufacturing process of turn-milling offers high productivity, high geometrical flexibility, safe chip breaking and machining of twist-free surfaces. However, the achievable accuracies and surface qualities do not allow the substitution of finish grinding processes. Thereby the dynamic profile of process forces is one of the main disturbance values. This paper presents a new process model of orthogonal eccentric turn-milling without axial feed. Thus the focus lies on the analysis of the process forces and their dynamic behavior caused by the changing chip cross section area on the face cutting edge. The developed model considers single and multiple cutting edge tools and has a geometrical-empirical character. This model describes the process kinematics and the error inducing process forces in orthogonal turn-milling. Their dynamic profile can be analyzed and minimized using multiple cutting edge tools and customized pre-machining of the workpiece surface topography with the goal of creating a robust process to substitute the finish grinding process in high precision applications. Such applications include, for example, the main and pin bearing seats of crank shafts used in the automotive and truck industry or even for large ship engines. The key feature is to minimize the form deviation of the cylindricity, which results from straightness and roundness of the workpiece surface to below 10 µm for crank shafts used in the truck industry. The model is adjusted and verified by experimental tests.
  • Publication
    Experimental investigations of bulge formation for burnishing on plain surfaces
    ( 2018)
    Putz, M.
    ;
    Dix, M.
    ;
    Stöckmann, R.
    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.
  • Publication
    Suspension technology for abrasive waterjet (AWJ) cutting of ceramics
    ( 2018)
    Putz, M.
    ;
    Dix, M.
    ;
    Morczinek, F.
    ;
    Dittrich, M.
    Hard machining of brittle materials like ceramics is a process-oriented challenge. It has been shown that abrasive water jet cutting is an appropriate alternative to commonly used diamond grinding or laser cutting processes. In Abrasive water jet machining the injection technology is currently used almost exclusively. Due to the realization of the suspension jet technology a higher cutting performance can be achieved. In this article the known injection principle and the suspension principle will be compared. Therefore, 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 and roughness parameters.
  • Publication
    High Precision Machining of Hybrid Layer Composites by Abrasive Waterjet Cutting
    ( 2018)
    Putz, M.
    ;
    Rennau, A.
    ;
    Dix, M.
    In industrial applications the increasing variety of high performance materials and their combination to material composites is challenging for the common machining processes. Their high application range combined with minimal forces and no significant thermal loads predestinates abrasive waterjet cutting for machining such complex structures. This paper verifies the high precision machinability of 2D- and 3D-layer composites out of CFRP and a lightweight metal such as aluminum or magnesium using the abrasive waterjet. Therefore, different cutting strategies were determined as well as process influences to the joining zone and characteristics of the machined component.
  • Publication
    Werkzeugkonzeption für das orthogonale Hochgenauigkeitsdrehfräsen
    ( 2017)
    Hertel, M.
    ;
    Dix, M.
    ;
    Putz, M.
    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.