Temat: thermal error - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Effects of hot chips in dry cutting processes on the temperature field and displacement of the machine tool table
Autorzy:: Albrecht, Tom
Thiem, Xaver
Penter, Lars
Ihlenfeldt, Steffen
Powiązania:: https://bibliotekanauki.pl/articles/99659.pdf
Data publikacji:: 2019
Wydawca:: Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:: accuracy
thermal error
deformation
Opis:: In machining up to 75% of the geometrical variations of work piece, features are caused by thermally induced deformations of machine components [1]. Since in dry cutting up to 80% of the thermal energy is stored in the chips [2], we expected a significant effect of these process-dependent heat sources on the machine accuracy. Based on preliminary simulation results, we systematically applied determined quantities of heated chips to a machine table to understand their impact on the temperature field. Temperature sensors where used to measure the temperature change on the tables surface and in the structure. Length measuring probes measured the corresponding deformations at 24 points distributed over the table. The measurements show a temperature change of 4 K at the surface and 3 K in the structure near the heat source after 6 minutes of exposure to 500°C chips. In this case, the impact on the temperature field is local but causes the bending of the table. We recorded 8 micron of thermo-elastic deformations. The results suggest that high-accuracy processes with large energy input, such as hard turning, require the heat induced into the machine structure by hot chips to be implemented into compensation methods and correction algorithms.
Źródło:: Journal of Machine Engineering; 2019, 19, 3; 31-42
1895-7595
2391-8071
Pojawia się w:: Journal of Machine Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Robustness and portability of machine tool thermal error compensation model based on control of participating thermal sources
Autorzy:: Mares, M.
Horejs, O.
Hornych, J.
Smolik, J.
Powiązania:: https://bibliotekanauki.pl/articles/99925.pdf
Data publikacji:: 2013
Wydawca:: Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:: control
machine tool
thermal error
transfer function
Opis:: Thermal errors caused by the influence of internal and external heat sources in machine tool structure can cause more than 50% of total machine tool inaccuracy. Therefore, research on thermal behavior of machine tool structures is crucial for successful manufacturing. This paper provides an insight into the modeling of highly nonlinear machine tool thermal errors using thermal transfer functions (TTF). The method is dynamic (uses machine tool thermal history) and its modeling and calculation speed is suitable for real-time applications. The method does not require interventions into the machine tool structure, uses very few additional gauges and solves separately each influence participating on thermal error. The paper focuses on the development of a robust thermal model sensitive to various machine tool thermal behavior nonlinearities with the help of minimum input information. Model was applied on real machine tool (portal milling centre) and was verified within a complicated electro-spindle revolution spectrum. Moreover, the said compensation model was applied on another machine tool to prove its robustness and portability among machines of the same type set and the results of the TTF model were compared with a model obtained via multiple linear regression (MLR) as a case study.
Źródło:: Journal of Machine Engineering; 2013, 13, 1; 24-36
1895-7595
2391-8071
Pojawia się w:: Journal of Machine Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Real-Time Compensation of Machine Tool Thermal Error Including Cutting Process
Autorzy:: Horejs, O.
Mares, M.
Hornych, J.
Powiązania:: https://bibliotekanauki.pl/articles/99782.pdf
Data publikacji:: 2015
Wydawca:: Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:: thermal error
real-time compensation
cutting process
Opis:: The challenge to be addressed by this paper is to extend the common machine tool thermal compensation models considering only internal heat sources to include the effects of the cutting process. Although real-time software compensations of thermal errors exist, the majority of these models only presume machine tools under load-free rotation of the main spindle without any reference to rough machining. The machining process is completely neglected in spite of the fact that it represents a significant heat source and causes workpiece inaccuracy. This paper presents a real-time compensation of three-axis vertical milling centre thermal errors including the cutting process effect. The simulation is based on dynamic modelling using transfer functions. The model was implemented into a standard CNC controller of a three-axis vertical milling centre to compensate for thermal errors in real time. The inputs of the compensation algorithm are the spindle rotational speed, the 5 temperatures of the machine structure and spindle power. A reduction of thermal errors achieved by using the new approximation TF model including cutting process impact is up to 79% for steel cutting tests with different cutting conditions.
Źródło:: Journal of Machine Engineering; 2015, 15, 3; 5-18
1895-7595
2391-8071
Pojawia się w:: Journal of Machine Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Decreasing of thermal errors in a lathe by forced cooling of ball screws and a headstock
Autorzy:: Winiarski, Z.
Kowal, Z.
Błażejewski, A.
Powiązania:: https://bibliotekanauki.pl/articles/1429161.pdf
Data publikacji:: 2008
Wydawca:: Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:: lathe
feed mechanism
cooling
thermal error
calculation
Opis:: The goal of this paper is to present the effective methods of decreasing thermal deformations of a turning centre's structure in order to reduce the thermal error. The design of a machine tool as well as the scope of analyses are described, and calculation methods are specified. The paper also presents the results of computer simulations, concerning studies on the influence of type and parameters of a headstock-cooling liquid on the reduction of spindle displacements. Moreover, the results of feed mechanism's thermal studies are shown, describing the influence of heat generated during the operation of ball screws and their inner liquid cooling, on tool's thermal displacements.
Źródło:: Journal of Machine Engineering; 2008, 8, 4; 122-130
1895-7595
2391-8071
Pojawia się w:: Journal of Machine Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Compensation of machine tool angular thermal errors using controlled internal heat sources
Autorzy:: Mares, M.
Horejs, O.
Hornych, J.
Kohut, P.
Powiązania:: https://bibliotekanauki.pl/articles/971270.pdf
Data publikacji:: 2011
Wydawca:: Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:: control
machine tool
angular thermal error
transfer function
Opis:: Thermal errors caused by the influence of internal and external heat sources in machine tool structure can cause up to 70% of total machine tool inaccuracy. Therefore, research on thermal behavior of machine tool structures is crucial for successful manufacturing. This paper provides an insight into the modeling of highly nonlinear (increasing with the complexity of the structure) machine tool thermal behavior using thermal transfer functions This approach to modeling is dynamic (uses thermal history) and, due to its relative simplicity, it enables real-time calculations. The method uses very few additional gauges and solves separately each influence participating in the thermal error. The main objective of the article is to describe the estimation of angular deformations occurring at the tool center point due to thermal influences. Transfer functions are used for the identification and control of additional internal heat sources. The second aim is to compare modeling effort with approximation quality. A partial objective is to cover other nonlinearities occurring generally in machine tool thermal behavior. The approach has been verified on a closed quill (a simple and symmetrical machine tool part) and applied on a model of a machine tool structure which has been chosen as the least favorable from the thermal point of view.
Źródło:: Journal of Machine Engineering; 2011, 11, 4; 78-90
1895-7595
2391-8071
Pojawia się w:: Journal of Machine Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Model-based, experimental thermoelastic analysis of a large scale turbine housing
Autorzy:: Emonts, Dominik
Sanders, Mark P.
Montavon, Benjamin
Schmitt, Robert H.
Powiązania:: https://bibliotekanauki.pl/articles/2052191.pdf
Data publikacji:: 2022
Wydawca:: Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:: thermal error modelling
large scale metrology
virtual climatisation
Opis:: Temporally and spatially unstable thermal conditions lead to inhomogeneous thermoelastic changes in the workpiece geometry. Consequently, non-negligible geometric deviations are evident, especially when measuring large workpieces with narrow tolerances, which often take place in non-climatized production environments and thus make thermal monitoring indispensable. Accurate determination of the thermoelastic behaviour for complex and large geometries is a challenging task with computationally effortful or less accurate existing solutions. Thus, the development of innovative measurement and modelling approaches is subject of current research, whereat physical validation is a prerequisite. Therefore, the authors developed a method, enabling the emulation of typical process heat cycles on a turbine housing in combination with a geometric measurement system. The idea is to provide reproducible and reversible thermal conditions on a representative large workpiece and to investigate the resulting geometric deformation in an economically viable way. Throughout this study, an analogy test rig is presented, integrating different temperature sensors, two geometric measurement systems and thermal deformation models into one demonstrator. The demonstrator's first applications show insightful results, revealing accordance, but also unexpected deviations between the predicted and measured quantities. Moreover, it provides great potential for validation of more complex modelling approaches and innovative thermal condition monitoring systems for large precision workpieces.
Źródło:: Journal of Machine Engineering; 2022, 22, 1; 84-95
1895-7595
2391-8071
Pojawia się w:: Journal of Machine Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Implementation and demonstration of characteristic diagram as well as structure model based correction of thermo-elastic tool center point displacements
Autorzy:: Putz, M.
Ihlenfeldt, S.
Kauschinger, B.
Naumann, C.
Thiem, X.
Riedel, M.
Powiązania:: https://bibliotekanauki.pl/articles/99680.pdf
Data publikacji:: 2016
Wydawca:: Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:: hexapod
characteristic diagram
thermal error
simulated
measured
correction algorithm
Opis:: In milling machines, waste heat from motors, friction effects on guides and most importantly the milling process itself greatly affect positioning accuracy and thus production quality. Therefore, active cooling and lead time are used to reach thermal stability. A cheaper and more energy-efficient approach is to gather sensor data from the machine tool to predict and correct the resulting tool center point displacement. Two such approaches are the characteristic diagram based and the structure model based correction algorithms which are briefly introduced in this paper. Both principles have never been directly compared on the same demonstration machine, under the equal environmental conditions and with the same measurement setup. The paper accomplishes this comparison ona hexapod kinematics examined in a thermal chamber,where the effectiveness of both approaches is measured and the strengths and weaknesses of both are pointed out.
Źródło:: Journal of Machine Engineering; 2016, 16, 3; 88-101
1895-7595
2391-8071
Pojawia się w:: Journal of Machine Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: An investigation of the relationship between encoder difference and thermo-elastic machine tool deformation
Autorzy:: Brecher, Christian
Dehn, Mathias
Neus, Stephan
Powiązania:: https://bibliotekanauki.pl/articles/24084708.pdf
Data publikacji:: 2023
Wydawca:: Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:: machine tool
thermal error compensation
machine learning
artificial neural network
Opis:: New approaches, using machine learning to model the thermo-elastic machine tool error, often rely on machine internal data, like axis speed or axis position as input data, which have a delayed relation to the thermo-elastic error. Since there is no direct relation to the thermo-elastic error, this can lead to an increased computation inaccuracy of the model or the need for expensive sensor equipment for additional input data. The encoder difference is easy to obtain and has a direct relationship with the thermo-elastic error and therefore has a high potential to improve the accuracy thermo-elastic error models. This paper first investigates causes of the encoder difference and its relationship with the thermo-elastic error. Afterwards, the model is presented, which uses the encoder difference to compute the thermo-elastic error. Due to the complexity of the relationship, it is necessary, to use a machine learning approach for this. To conclude, the potential of the encoder difference as an input of the model is evaluated.
Źródło:: Journal of Machine Engineering; 2023, 23, 3; 26--37
1895-7595
2391-8071
Pojawia się w:: Journal of Machine Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Application of machine learning in the precise and cost-effective self-compensation of the thermal errors of CNC machine tools – a review
Autorzy:: Czwartosz, Robert
Jedrzejewski, Jerzy
Powiązania:: https://bibliotekanauki.pl/articles/2142358.pdf
Data publikacji:: 2022
Wydawca:: Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:: CNC machine tool
thermal error compensation
machine learning
self-learning
Opis:: The current development of production engineering takes place through the innovative improvement of machine tools and machining processes at the constantly growing application of intelligent self-improvement functions. Machine learning opens up possibilities for machine tool self-improvement in real time. This paper discusses the state of knowledge relating to the application of machine learning for precise and cost-effective thermal error self-compensation. Data acquisition and processing, models and model learning and self-learning methods are also considered. Three highly effective error compensation systems (supported with machine learning) are analysed and conclusions and recommendations for future research are formulated.
Źródło:: Journal of Machine Engineering; 2022, 22, 3; 59--77
1895-7595
2391-8071
Pojawia się w:: Journal of Machine Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Advanced Thermal Error Compensation of a Floor Type Machining Centre Allowing for the Influence of Interchangeable Spindle Heads
Autorzy:: Mares, M.
Horejs, O.
Hornych, J.
Powiązania:: https://bibliotekanauki.pl/articles/99507.pdf
Data publikacji:: 2015
Wydawca:: Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:: heavy-duty machine tool
real-time compensation
thermal error
spindle head
Opis:: Thermal errors caused by internal and external heat sinks and sources may cause more than 50% of machine tool (MT) total error. Demands on machining accuracy and machine time utilization are still increasing. Therefore, research on thermal behaviour of MT structures is crucial for successful manufacturing. Direct (measuring between tool and work-piece) and indirect (predictive models) approaches to compensation of thermo-dependent tool centre point (TCP) displacement can be used to reduce sensitivity to heat flow or temperature control of MT and its environment. Thermal error indirect compensation is one of the techniques widely employed to reduce thermal errors due to its cost-effectiveness and ease of implementation. This paper is a continuation of scientific work on the modelling of complex MT thermal behaviour using a dynamic method with a physical basis: thermal transfer functions (TF). Previously published works focusing on middle-sized MTs are extended here to include heavy-duty MT application. Particular attention is paid to issues concerning compensation of thermal errors caused by interchangeable spindle heads.
Źródło:: Journal of Machine Engineering; 2015, 15, 3; 19-32
1895-7595
2391-8071
Pojawia się w:: Journal of Machine Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 11.

Tytuł:: Handling ambient temperature changes in correlative thermal error compensation
Autorzy:: Naumann, Christian
Geist, Alexander
Putz, Matthias
Powiązania:: https://bibliotekanauki.pl/articles/28407326.pdf
Data publikacji:: 2023
Wydawca:: Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:: machine tool
thermal error
correlative compensation model
ambient effect
ETVE
environmental temperature variation error
Opis:: Thermal errors are one of the leading causes for positioning inaccuracies in modern machine tools. These errors are caused by various internal and external heat sources and sinks, which shape the machine tool’s temperature field and thus its deformation. Model based thermal error prediction and compensation is one way to reduce these inaccuracies. A new composite correlative model for the compensation of both internal and external thermal effects is presented. The composite model comprises a submodel for slow long- and medium-term ambient changes, one for short-term ambient changes and one for all internal thermal influences. A number of model assumptions are made to allow for this separation of thermal effects. The model was trained using a large number of FE simulations and validated online in a five-axis machine tool with measurements in a climate chamber. Despite the limitations, the compensation model achieved good predictions of the thermal error for both normal ambient conditions (21°C) and extreme ambient conditions (35°C).
Źródło:: Journal of Machine Engineering; 2023, 23, 4; 43--63
1895-7595
2391-8071
Pojawia się w:: Journal of Machine Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 12.

Tytuł:: Optimized grid structures for the characteristic diagram based estimation of thermo-elastic tool center point displacements in machine tools
Autorzy:: Putz, M.
Ihlenfeldt, S.
Naumann, C.
Glänzel, J.
Powiązania:: https://bibliotekanauki.pl/articles/100061.pdf
Data publikacji:: 2017
Wydawca:: Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:: characteristic diagram
adaptive structured grids
thermoelastic deformation
grid optimization
thermal error estimation
Opis:: It is a well-known problem of milling machines, that waste heat from motors, friction effects on guides and also the milling process itself greatly affect the positioning accuracy and thus the production quality. An economic and energy-efficient method of correcting this thermo-elastic positioning error is to gather sensor data from the machine tool and the process and to use that information to predict and correct the resulting tool center point displacement using high dimensional characteristic diagrams. The size of these characteristic diagrams depends on the number of input variables (sensors) and the fineness of the discretization of the grid. While the number of sensors can usually not be reduced without affecting the quality of the prediction, it is often possible to minimize the size of characteristic diagrams through the use of adaptive grid refinement. This ensures that the finest grid sections correspond with the load cases that have the largest local gradients. Through such adaptive refinement, it is possible to reduce storage capacity and computation time without significant loss of precision. The aim of this article is to examine, test and compare different methods of adaptive grid refinement. For this, simulation data from a machine tool is used.
Źródło:: Journal of Machine Engineering; 2017, 17, 3; 36-50
1895-7595
2391-8071
Pojawia się w:: Journal of Machine Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 13.

Tytuł:: Efficient quantification of free and forced convection via the decoupling of thermo-mechanical and thermo-fluidic simulations of machine tools
Autorzy:: Glaenzel, J.
Ihlenfeldt, S.
Naumann, C.
Putz, M.
Powiązania:: https://bibliotekanauki.pl/articles/100153.pdf
Data publikacji:: 2018
Wydawca:: Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:: thermal effects
simulation
machine tool
environment
positioning error
Opis:: Thermo-elastic deformations represent one of the main reasons for positioning errors in machine tools. Investigations of the thermo-mechanical behaviour of machine tools, especially during the design phase, rely mainly on thermo-elastic simulations. These require the knowledge of heat sources and sinks and assumptions on the heat dissipation via convection, conduction and radiation. Forced convection such as that caused by moving assemblies has both a large influence on the heat dissipation to the surrounding air. The most accurate way of taking convection into account is via computational fluid dynamics (CFD) simulations. These simulations compute heat transfer coefficients for every finite element on the machine tool surface, which can then be used as boundary conditions for accurate thermo-mechanical simulations. Transient thermo-mechanical simulations with moving assemblies thus require a CFD simulation during each time step, which is very time-consuming. This paper presents an alternative by using characteristic diagrams to interpolate the CFD simulations. The new method uses precomputed thermal coefficients of a small number of load cases as support points to estimate the convection of all relevant load cases (i.e. ambient conditions). It will be explained and demonstrated on a machine tool column.
Źródło:: Journal of Machine Engineering; 2018, 18, 2; 41-53
1895-7595
2391-8071
Pojawia się w:: Journal of Machine Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 14.

Tytuł:: Parallel computing in automation of decoupled fluid-thermostructural simulation approach
Autorzy:: Glänzel, Janine
Naumann, Andreas
Kumar, Tharun Suresh
Powiązania:: https://bibliotekanauki.pl/articles/100135.pdf
Data publikacji:: 2020
Wydawca:: Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:: thermal effects
simulation
machine tool
environment
positioning error
Opis:: Decoupling approach presents a novel solution/alternative to the highly time-consuming fluid-thermal-structural simulation procedures when thermal effects and resultant displacements on machine tools are analyzed. Using high dimensional Characteristic Diagrams (CDs) along with a Clustering Algorithm that immensely reduces the data needed for training, a limited number of CFD simulations can suffice in effectively decoupling fluid and thermal-structural simulations. This approach becomes highly significant when complex geometries or dynamic components are considered. However, there is still scope for improvement in the reduction of time needed to train CDs. Parallel computation can be effectively utilized in decoupling approach in simultaneous execution of (i) CFD simulations and data export, and (ii) Clustering technique involving Genetic Algorithm and Radial Basis Function interpolation, which clusters and optimizes the training data for CDs. Parallelization reduces the entire computation duration from several days to a few hours and thereby, improving the efficiency and ease-of-use of decoupling simulation approach.
Źródło:: Journal of Machine Engineering; 2020, 20, 2; 39-52
1895-7595
2391-8071
Pojawia się w:: Journal of Machine Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 15.

Tytuł:: Parameterization of environmental influences by automated characteristic diagrams for the decoupled fluid and structural-mechanical simulations
Autorzy:: Glänzel, Janine
Kumar, Tharun Suresh
Naumann, Christian
Putz, Matthias
Powiązania:: https://bibliotekanauki.pl/articles/99399.pdf
Data publikacji:: 2019
Wydawca:: Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:: thermal effects
simulation
machine tool
environment
positioning error
Opis:: Thermo-elastic effects contribute the most to positioning errors in machine tools especially in operations where high precision machining is involved. When a machine tool is subjected to changes in environmental influences such as ambient air temperature, velocity or direction, then flow (CFD) simulations are necessary to effectively quantify the thermal behaviour between the machine tool surface and the surrounding air (fluid). Heat transfer coefficient (HTC) values effectively represent this solid-fluid heat transfer and it serves as the boundary data for thermo-elastic simulations. Thereby, deformation results can be obtained. This two-step simulation procedure involving fluid and thermo-structural simulations is highly complex and time-consuming. A suitable alternative for the above process can be obtained by introducing a clustering algorithm (CA) and characteristic diagrams (CDs) in the workflow. CDs are continuous maps of a set of input variables onto a single output variable, which are trained using data from a limited number of CFD simulations which is optimized using the clustering technique involving genetic algorithm (GA) and radial basis function (RBF) interpolation. The parameterized environmental influences are mapped directly onto corresponding HTC values in each CD. Thus, CDs serve as look-up tables which provide boundary data (HTC values along with nodal information) under several load cases (combinations of environmental influences) for thermo-elastic simulations. Ultimately, a decoupled fluid-structural simulation system is obtained where boundary (convection) data for thermo-mechanical simulations can be directly obtained from CDs and would no longer require fluid simulations to be carried out again. Thus, a novel approach for the correction of thermo-elastic deformations on a machine tool is obtained.
Źródło:: Journal of Machine Engineering; 2019, 19, 1; 98-113
1895-7595
2391-8071
Pojawia się w:: Journal of Machine Engineering
Dostawca treści:: Biblioteka Nauki

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