Cooling of motor spindles - a review

Thermally induced loads in motor spindles can cause a number of undesired effects. As a result, the process capability of spindles, and thus, the productivity of a process can decrease. Future motor spindles will be exposed to higher mechanical and especially thermal loads due to trends aiming to increase power densities and maximum speeds. These trends are amplified by increasingly powerful drive concepts and developments in bearing technology. Therefore, researchers assume that it will not be possible to raise the performance potential of spindles due to insufficient cooling of its heat sources. A series of different cooling concepts have been researched and developed in recent decades. These developments have been made for different purposes. They also differ considerably in terms of their cooling principles and cooling performance. In this article, these cooling approaches and the motivations for their development are described. Firstly, the causes of heat development in motor spindles are described in a historical context. Subsequently, the effects of heat development on the manufacturing-relevant properties of motor spindles are revealed. Finally, current deficits in the area of spindle cooling and the need for the development and transfer into industrial practice of more efficient and cost-effective cooling concepts to overcome future challenges are discussed. © 2020, The Author(s)

The Application of ANN and ANFIS Prediction Models for Thermal Error Compensation on CNC Machine Tools

Thermal errors can have significant effects on Computer Numerical Control (CNC) machine tool accuracy. The errors come from thermal deformations of the machine elements caused by heat sources within the machine structure or from ambient temperature change. The effect of temperature can be reduced by error avoidance or numerical compensation. The performance of a thermal error compensation system essentially depends upon the accuracy and robustness of the thermal error model and its input measurements. This thesis first reviews different methods of designing thermal error models, before concentrating on employing Artificial Intelligence (AI) methods to design different thermal prediction models. In this research work the Adaptive Neuro-Fuzzy Inference System (ANFIS) is used as the backbone for thermal error modelling. The choice of inputs to the thermal model is a non-trivial decision which is ultimately a compromise between the ability to obtain data that sufficiently correlates with the thermal distortion and the cost of implementation of the necessary feedback sensors. In this thesis, temperature measurement was supplemented by direct distortion measurement at accessible locations. The location of temperature measurement must also provide a representative measurement of the change in temperature that will affect the machine structure. The number of sensors and their locations are not always intuitive and the time required to identify the optimal locations is often prohibitive, resulting in compromise and poor results. In this thesis, a new intelligent system for reducing thermal errors of machine tools using data obtained from thermography data is introduced. Different groups of key temperature points on a machine can be identified from thermal images using a novel schema based on a Grey system theory and Fuzzy C-Means (FCM) clustering method. This novel method simplifies the modelling process, enhances the accuracy of the system and reduces the overall number of inputs to the model, since otherwise a much larger number of thermal sensors would be required to cover the entire structure. An Adaptive Neuro-Fuzzy Inference System with Fuzzy C-Means clustering (ANFIS-FCM) is then employed to design the thermal prediction model. In order to optimise the approach, a parametric study is carried out by changing the number of inputs and number of Membership Functions (MFs) to the ANFIS-FCM model, and comparing the relative robustness of the designs. The proposed approach has been validated on three different machine tools under different operation conditions. Thus the proposed system has been shown to be robust to different internal heat sources, ambient changes and is easily extensible to other CNC machine tools. Finally, the proposed method is shown to compare favourably against alternative approaches such as an Artificial Neural Network (ANN) model and different Grey models

Assessment of the Uncoated Carbide inserts in end milling of Titanium Alloy Ti-6AI-4V

This paper investigates the effect of the uncoated carbide inserts in end milling of titanium alloy Ti-6AI-4V under dry conditions. CNC Bridgeport VMC machining was employed during the experimentations. Sandvick end milling of uncoated tungsten carbide inserts were chosen as the cutting tools. The effect of cutting parameter, i.e. cutting speed, feed, and axial depth of cut on tool wear morphology, surface roughness and chip segmentations are comprehensively investigated. Scanning electron microscope is utilized for these purposes. Flank wear has been considered as the criteria for tool failure and the wear was measured using a scanning electron microscope. Primary and secondary chip serrations also appear on the chip segmentations. The surface of titanium alloy is easily damaged during machining operations due to their poor machinability. Surface roughness generally increases with the increase of feed

Conference on Thermal Issues in Machine Tools: Proceedings

Inhomogeneous and changing temperature distributions in machine tools lead to sometimes considerable quality problems in the manufacturing process. In addition, the switching on and off of aggregates, for example, leads to further fluctuations in the temperature field of machine tools. More than 100 specialists discussed these and other topics from the field of thermal research at the 1st Conference on Termal Issues in Machine Tools in Dresden from 22 to 23 March.:Efficient modelling and computation of structure-variable thermal behavior of machine tools S. Schroeder, A. Galant, B. Kauschinger, M. Beitelschmidt Parameter identification software for various thermal model types B. Hensel, S. Schroeder, K. Kabitzsch Minimising thermal error issues on turning centre M. Mareš, O. Horejš, J. Hornych The methods for controlled thermal deformations in machine tools A. P. Kuznetsov, H.-J. Koriath, A.O. Dorozhko Efficient FE-modelling of the thermo-elastic behaviour of a machine tool slide in lightweight design C. Peukert, J. Müller, M. Merx, A. Galant, A. Fickert, B. Zhou, S. Städtler, S. Ihlenfeldt, M. Beitelschmidt Development of a dynamic model for simulation of a thermoelectric self-cooling system for linear direct drives in machine tools E. Uhlmann, L. Prasol, S.Thom, S. Salein, R. Wiese System modelling and control concepts of different cooling system structures for machine tools J. Popken, L. Shabi, J. Weber, J. Weber The electric drive as a thermo-energetic black box S. Winkler, R. Werner Thermal error compensation on linear direct drive based on latent heat storage I. Voigt, S. Winkler, R. Werner, A. Bucht, W.-G. Drossel Industrial relevance and causes of thermal issues in machine tools M. Putz, C. Richter, J. Regel, M. Bräunig Clustering by optimal subsets to describe environment interdependencies J. Glänzel, R. Unger, S. Ihlenfeldt Using meta models for enclosures in machine tools F. Pavliček, D. P. Pamies, J. Mayr, S. Züst, P. Blaser, P. Hernández-Becerro, K. Wegener Model order reduction of thermal models of machine tools with varying boundary conditions P. Hernández-Becerro, J. Mayr, P. Blaser, F. Pavliček, K. Wegener Effectiveness of modelling the thermal behaviour of the ball screw unit with moving heat sources taken into account J. Jedrzejewski, Z. Kowal, W. Kwasny, Z. Winiarski Analyzing and optimizing the fluidic tempering of machine tool frames A. Hellmich, J. Glänzel, A. Pierer Thermo-mechanical interactions in hot stamping L. Penter, N. Pierschel Experimental analysis of the heat flux into the grinding tool in creep feed grinding with CBN abrasives C. Wrobel, D. Trauth, P. Mattfeld, F. Klocke Development of multidimensional characteristic diagrams for the real-time correction of thermally caused TCP-displacements in precise machining M. Putz, C. Oppermann, M. Bräunig Measurement of near cutting edge temperatures in the single point diamond turning process E. Uhlmann, D. Oberschmidt, S. Frenzel, J. Polte Investigation of heat flows during the milling processes through infrared thermography and inverse modelling T. Helmig, T. Augspurger, Y. Frekers, B. Döbbeler, F. Klocke, R. Kneer Thermally induced displacements of machine tool structure, tool and workpiece due to cutting processes O. Horejš, M. Mareš, J. Hornych A new calibration approach for a grey-box model for thermal error compensation of a C-Axis C. Brecher, R. Spierling, M. Fey Investigation of passive torque of oil-air lubricated angular contact ball bearing and its modelling J. Kekula, M. Sulitka, P. Kolář, P. Kohút, J. Shim, C. H. Park, J. Hwang Cooling strategy for motorized spindle based on energy and power criterion to reduce thermal errors S. Grama, A. N. Badhe, A. Mathur Cooling potential of heat pipes and heat exchangers within a machine tool spindleo B. Denkena, B. Bergman, H. Klemme, D. Dahlmann Structure model based correction of machine tools X. Thiem, B. Kauschinger, S. Ihlenfeldt Optimal temperature probe location for the compensation of transient thermal errors G. Aguirre, J. Cilla, J. Otaegi, H. Urreta Adaptive learning control for thermal error compensation on 5-axis machine tools with sudden boundary condition changes P. Blaser, J. Mayr, F. Pavliček, P. Hernández-Becerro, K. Wegener Hybrid correction of thermal errors using temperature and deformation sensors C. Naumann, C. Brecher, C. Baum, F. Tzanetos, S. Ihlenfeldt, M. Putz Optimal sensor placement based on model order reduction P. Benner, R. Herzog, N. Lang, I. Riedel, J. Saak Workpiece temperature measurement and stabilization prior to dimensional measurement N. S. Mian, S. Fletcher, A. P. Longstaff Measurement of test pieces for thermal induced displacements on milling machines H. Höfer, H. Wiemer Model reduction for thermally induced deformation compensation of metrology frames J. v. d. Boom Local heat transfer measurement A. Kuntze, S. Odenbach, W. Uffrecht Thermal error compensation of 5-axis machine tools using a staggered modelling approach J. Mayr, T. Tiberini. P. Blaser, K. Wegener Design of a Photogrammetric Measurement System for Displacement and Deformation on Machine Tools M. Riedel, J. Deutsch, J. Müller. S. Ihlenfeldt Thermography on Machine Tools M. Riedel, J. Deutsch, J. Müller, S. Ihlenfeldt Test piece for thermal investigations of 5-axis machine tolls by on-machine measurement M. Wiesener. P. Blaser, S. Böhl, J. Mayr, K. Wegene

Research reports: 1990 NASA/ASEE Summer Faculty Fellowship Program

Reports on the research projects performed under the NASA/ASEE Summer Faculty Fellowship Program are presented. The program was conducted by The University of Alabama and MSFC during the period from June 4, 1990 through August 10, 1990. Some of the topics covered include: (1) Space Shuttles; (2) Space Station Freedom; (3) information systems; (4) materials and processes; (4) Space Shuttle main engine; (5) aerospace sciences; (6) mathematical models; (7) mission operations; (8) systems analysis and integration; (9) systems control; (10) structures and dynamics; (11) aerospace safety; and (12) remote sensin

Book of abstracts of the 15th International Symposium of Croatian Metallurgical Society - SHMD \u272022, Materials and metallurgy

Book of abstracts of the 15th International Symposium of Croatian Metallurgical Society - SHMD \u272022, Materials and metallurgy, Zagreb, Croatia, March 22-23, 2022. Abstracts are organized in four sections: Materials - section A; Process metallurgy - Section B; Plastic processing - Section C and Metallurgy and related topics - Section D

Book of abstracts of the 15th International Symposium of Croatian Metallurgical Society - SHMD \u272022, Materials and metallurgy

Book of abstracts of the 15th International Symposium of Croatian Metallurgical Society - SHMD \u272022, Materials and metallurgy, Zagreb, Croatia, March 22-23, 2022. Abstracts are organized in four sections: Materials - section A; Process metallurgy - Section B; Plastic processing - Section C and Metallurgy and related topics - Section D

Development of the UMAC-based control system with application to 5-axis ultraprecision micromilling machines

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Increasing demands from end users in the fields of optics, defence, automotive, medical, aerospace, etc. for high precision 3D miniaturized components and microstructures from a range of materials have driven the development in micro and nano machining and changed the manufacturing realm. Conventional manufacturing processes such as chemical etching and LIGA are found unfavourable or limited due to production time required and have led mechanical micro machining to grow further. Mechanical micro machining is an ideal method to produce high accuracy micro components and micro milling is the most flexible enabling process and is thus able to generate a wider variety of complex micro components and microstructures. Ultraprecision micromilling machine tools are required so as to meet the accuracy, surface finish and geometrical complexity of components and parts. Typical manufacturing requirements are high dimensional accuracy being better than 1 micron, flatness and roundness better than 50 nm and surface finish ranging between 10 and 50 nm. Manufacture of high precision components and parts require very intricate material removal procedure. There are five key components that include machine tools, cutting tools, material properties, operation variables and environmental conditions, which constitute in manufacturing high quality components and parts. End users assess the performance of a machine tool based on the dimensional accuracy and surface quality of machined parts including the machining time. In this thesis, the emphasis is on the design and development of a control system for a 5-axis bench-type ultraprecision micromilling machine- Ultra-Mill. On the one hand, the developed control system is able to offer high motion and positioning accuracy, dynamic stiffness and thermal stability for motion control, which are essential for achieving the machining accuracy and surface finish desired. On the other hand, the control system is able to undertake in-process inspection and condition monitoring of the machine tool and process. The control of multi-axis precision machines with high-speed and high-accuracy motions and positioning are desirable to manufacture components with high accuracy and complex features to increase productivity and maintain machine stability, etc. The development of the control system has focused on fast, accurate and robust positioning requirements at the machine system design stage. Apart from the mechanical design, the performance of the entire precision systems is greatly dependent on diverse electrical and electronics subsystems, controllers, drive instruments, feedback devices, inspection and monitoring system and software. There are some variables that dynamically alter the system behaviour and sensitivity to disturbance that are not ignorable in the micro and nano machining realm. In this research, a structured framework has been developed and integrated to aid the design and development of the control system. The framework includes critically reviewing the state of the art of ultraprecision machining tools, understanding the control system technologies involved, highlighting the advantages and disadvantages of various control system methods for ultraprecision machines, understanding what is required by end-users and formulating what actually makes a machine tool be an ultraprecision machine particularly from the control system perspective. In the design and development stage, the possession of mechatronic know-how is essential as the design and development of the Ultra-Mill is a multidisciplinary field. Simulation and modelling tool such as Matlab/Simulink is used to model the most suitable control system design. The developed control system was validated through machining trials to observe the achievable accuracy, experiments and testing of subsystems individually (slide system, tooling system, monitoring system, etc.). This thesis has successfully demonstrated the design and development of the control system for a 5-axis ultraprecision machine tool- Ultra-Mill, with high performance characteristics, fast, accurate, precise, etc. for motion and positioning, high dynamic stiffness, robustness and thermal stability, whereby was provided and maintained by the control system

A Multi-Band Far-Infrared Survey with a Balloon-Borne Telescope

Nine additional radiation sources, above a 3-sigma confidence level of 1300 Jy, were identified at 100 microns by far infrared photometry of the galactic plane using a 0.4 meter aperture, liquid helium cooled, multichannel far infrared balloon-borne telescope. The instrument is described, including its electronics, pointing and suspension systems, and ground support equipment. Testing procedures and flight staging are discussed along with the reduction and analysis of the data acquired. The history of infrared astronomy is reviewed. General infrared techniques and the concerns of balloon astronomers are explored