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Wyszukujesz frazę "error" wg kryterium: Temat


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
Artykuł
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
Artykuł
Tytuł:
CNC machine tool error compensation system implementation strategies and their constraints
Autorzy:
Medyk, Pawel
Jedrzejewski, Jerzy
Kasprzak, Marcin
Powiązania:
https://bibliotekanauki.pl/articles/99941.pdf
Data publikacji:
2019
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
machine tools error
compensation
control system
Opis:
This paper deals with the constraints imposed on error compensation systems by their implementation strategies. Constraints stemming from the structure of the control system with an NCK architecture of the ADCBI type are presented. Practical realizations of compensation and potential solutions offered by contemporary commercial CNC controllers are discussed.
Źródło:
Journal of Machine Engineering; 2019, 19, 4; 70-81
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Survey of machine tool error measuring methods
Autorzy:
Kwaśny, W.
Turek, P.
Jędrzejewski, J.
Powiązania:
https://bibliotekanauki.pl/articles/100074.pdf
Data publikacji:
2011
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
machine tool
volumetric error
identification
method
Opis:
This paper presents the factors and needs which make it necessary to increase the accuracy of machine tools. Types of machine tool errors, their causes and ways of identifying, measuring, reducing and compensating them are described. The most effective methods of identifying machine tool errors are discussed and classified. The measuring methods and tools are compared with regard to their range of application, time consumption, cost, market availability and main limitations.
Źródło:
Journal of Machine Engineering; 2011, 11, 4; 7-38
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spindle Error Movements Measurement Algorithm and a New Method of Results Analysis
Autorzy:
Jemielniak, K.
Chrzanowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/99896.pdf
Data publikacji:
2015
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
machine tool accuracy
metrology
spindle error motions
Opis:
Machining accuracy depends not only on geometric precision, but also on machine tool spindle error motions. This is particularly important for machining with high rotational speed. Spindle error movements are precisely defined and the method of their measurement methodology is standardized (ISO 230-7 and B89.3.4). Also devices for measuring the error movements are generally known. The main problem is the development of algorithms to ensure the proper measurement, interpretation accordingly to the standards, especially considering so called sensitive and non-sensitive directions. This paper presents an approach and algorithms of spindle errors movements measurement. The proposed methodology is more reliable than commercial solutions.
Źródło:
Journal of Machine Engineering; 2015, 15, 1; 25-35
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Knowledge base and assumptions for holistic modelling aimed at reducing axial errors of complex machine tools
Autorzy:
Jędrzejewski, J.
Kwaśny, W.
Powiązania:
https://bibliotekanauki.pl/articles/99902.pdf
Data publikacji:
2013
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
holistic model
machine tool
power losses
error
Opis:
The paper presents the idea and need for the holistic modelling of machine tools. The complexity of such modelling is illustrated for a 5-axis machining centre. The need to model errors in the controllable axes of machine tools with rotational and linear motion drives is indicated. The physical dependences having a bearing on the state of deformations produced by temperature and dynamic forces, as well as the assumptions and computational modelsof shift generation in the high-speed bearing sets of spindles, and models of the behaviour of the ball screw are presented. Moreover, the results of experimental studies of the thermal behaviour of linear motor sets and guideways with rolling blocks are reported.
Źródło:
Journal of Machine Engineering; 2013, 13, 2; 7-25
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
Tytuł:
Improved machining performance through turn-milling
Autorzy:
Berenji, Kaveh Rahimzadeh
Budak, Erhan
Powiązania:
https://bibliotekanauki.pl/articles/2086273.pdf
Data publikacji:
2022
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
turn milling
tool life
surface error
chip geometry
Opis:
As a multi-axis metal cutting operation, turn-milling has the combined characteristics of conventional turning and milling operations involving rotating workpiece and milling tool with linear feed motion in the workpiece axis direction. Although turn-milling offers many advantages in machining complex and hard-to-cut materials due to its flexible kinematics, the process presents specific challenges. The main objective of this paper is to present an overview of turn-milling operations from different perspectives. In this regard, first, the advantages of turn-milling in terms of tool life are presented. An analytical approach is given based on process kinematics to achieve better surface quality and productivity simultaneously. Additionally, the uncut chip geometry and the cutting force models are presented with experimental verification.
Źródło:
Journal of Machine Engineering; 2022, 22, 2; 5--17
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł

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