Wyniki wyszukiwania - BazTech

1

Development of FEM thermal simulation technology for machine tool with enclosures and its application

Tanabe Ikuo, Suzuki Naohiko, Ishino Yoshiaki, Isobe Hiromi

Journal of Machine Engineering

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2024

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Vol. 24, No. 1

17--28

EN

These days, most machine tools are interlocked by an enclosure for safety control. At that time, internal heat generation in machine tools first causes thermal deformation of the machine structure, which reduces the machining accuracy of the workpiece. Furthermore, the internal heat generation heats the air inside the enclosure, causing a heat build-up phenomenon, and the trapped heat causes re-thermal deformation of the machine tool structure. As a result, machine tools with enclosures are subject to extremely complex thermal deformation. On the other hand, we would like to use FEM thermal simulation to study thermal deformation countermeasures for machine tools with enclosures at the design stage, but it is difficult to analyse the heat build-up phenomenon usingconventional FEM thermal simulation. In this research, the new FEM thermal simulation technology for the heat build-up phenomenon was developed and heat build-up phenomenon in a CNC lathe with enclosure was calculated using the proposed FEM simulation technology. As a result, it had been concluded that the proposed FEM simulation could calculate with high accuracy for the phenomenon of heat build-up in a CNC lathe with enclosure, and the proposed technology is very effective in the design.

2

Wykorzystanie obróbki plastycznej we współczesnych procesach wytwórczych

Styp-Rekowski Michał, Matuszewski Maciej, Polishchuk Oleg

Obróbka Metalu

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2023

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nr 2

52--57

PL

W artykule wskazano cechy obróbki plastycznej, które powodują, że ta technika obróbki jest szeroko stosowana we współczesnych procesach produkcyjnych. Ukazano także możliwości wspomagania tego rodzaju obróbki innymi technikami, np. laserem, w wyniki czego realizowane procesy nabierają charakteru hybrydowego. Zaprezentowano maszyny, narzędzia i procesy technologiczne, które powodują takie duże zainteresowanie tą techniką ze strony przemysłu.

EN

In this paper the features of plastic forming that make this processing technique widely used in modern production processes were described . The possibilities of supporting this type of processing with other techniques, e. g. laser, were also shown. The reason for this is that the implemented processes becoming a hybrid character. Machines, tools and technological processes that cause such great interest in this technology from the industry were presented.

3

Uncertainty evaluation of multilateration-based geometric error measurement considering the repeatibility of positioning of the machine tool

Liu Xingbao, Xia Yangqiu, Rui Xiaoting

Metrology and Measurement Systems

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2023

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Vol. 30, nr 1

49--63

EN

The sequential multilateration principle is often adopted in geometric error measurement of CNC machine tools. To identify the geometric errors, a single laser tracker is placed at different positions to measure the length between the target point and the laser tracker. However, the measurement of each laser tracker position is not simultaneous and measurement accuracy is mainly subject to positioning repeatability of the machine tool. This paper attempts to evaluate the measurement uncertainty of geometric errors caused by the positioning repeatability of the machine tool and the laser tracker spatial length measurement error based on the Monte Carlo method. Firstly, a direct identification method for geometric errors of CNC machine tools based on geometric error evaluation constraints is introduced, combined with the geometric error model of a three-axis machine tool. Moreover, uncertainty contributors caused by the repeatability of positioning of numerically controlled axes of the machine tool and the laser length measurement error are analyzed. The measurement uncertainty of the geometric error and the volumetric positioning error is evaluated with the Monte Carlo method. Finally, geometric error measurement and verification experiments are conducted. The results show that the maximum volumetric positioning error of the machine tool is 84.1 μm and the expanded uncertainty is 5.8 μm (𝑘 = 2). The correctness of the geometric error measurement and uncertainty evaluation method proposed in this paper is verified compared with the direct geometric error measurement methods.

4

Recent advances in precision, sustainability and safety of machine tools

Uhlmann Eckart

Journal of Machine Engineering

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2023

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Vol. 23, No. 3

5--25

EN

Machine tools are the main driver of economic, environmental and social sustainability in industrial production. The ongoing shift from mass production to highly individualized, small batch manufacturing requires machine tools to be more flexible to changing needs while maintaining at least the same level of productivity. However, flexibility and productivity are at odds with the necessity for resource and energy efficiency. At the same time, more sophisticated workpiece specifications are pushing the boundaries regarding precision and dynamics of machine tools. In such a high-performance context, machine safety plays a major role and is becoming increasingly challenging due to higher kinetic energies of moving components. This paper examines recent advances in machine tool precision, sustainability, and safety. Six comprehensive case studies are provided to illustrate how these improvements contribute to an increased productivity. Hardware and software solutions for pose-controlled robotic manufacturing and thermoelectrically tempered high-performance spindles will be presented. Modular machine tool frames based on building blocks and an adaptive cooling system with thermoelectric generators for linear direct drives demonstrate their major impact on resource and energy efficiency. Machine safety is addressed through an analysis of potential hazards as well as improved protective measures. Model-based predictions precisely identify critical process parameters that lead to unbalance-induced failure of slim tool extensions, while on the protection side, new statistical models are applied to assess the protective performance of safeguards much more accurately. The cutting-edge technologies for machine tools presented in this paper will help manufacturers to cope with current and future challenges in industrial production.

5

Handling ambient temperature changes in correlative thermal error compensation

Naumann Christian, Geist Alexander, Putz Matthias

Journal of Machine Engineering

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2023

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Vol. 23, No. 4

43--63

EN

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).

6

An investigation of the relationship between encoder difference and thermo-elastic machine tool deformation

Brecher Christian, Dehn Mathias, Neus Stephan

Journal of Machine Engineering

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2023

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Vol. 23, No. 3

26--37

EN

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.

7

Orthotropic model of rolling bearing in modeling lathe spindle dynamics

Tomaszewski Jan, Dunaj Paweł, Powałka Bartosz, Jasiewicz Marcin

Journal of Theoretical and Applied Mechanics

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2022

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Vol. 60 nr 1

17--31

EN

This paper presents a method for simplified modeling of bearing nodes of a lathe spindle using the finite element method. The proposed modeling methodology is based on the use of an orthotropic material model, which is used to reflect the stiffness properties of the bearing, both in the radial and axial directions. The modeling results have been experimentally verified. This resulted in full agreement of the mode shapes, an average relative error of the natural frequency values of 1.48% and high agreement of the receptance function.

8

Spatial compliance measurement of a clamping table with integrated force sensors

Friedrich Christian, Ihlenfeldt Steffen

Journal of Machine Engineering

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2022

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Vol. 22, No. 1

70--83

EN

Force sensor integration into machine components is a promising approach to measure spatial process forces, especially, when regarding hexapod structures and kinematics. Rigid still-standing hexapod frameworks, such as clamping tables, are particular suitable for this approach, as no dynamic influences need to be taken into account within the measurement model and they allow a measurement in 6 degrees of freedom. On the other hand, the stiffness of rigid frameworks is reduced by force sensor integration significantly. In addition, many approaches apply joints or flexure hinges to reduced lateral forces and improve the measuring quality, which reduce the stiffness even more. In this contribution, the compliance of a clamping table with integrated force sensors and flexure hinges is determined by experimental measurements using a multiline laser interferometer, by analytic calculation, and by finite element simulation. In conclusion, the amount of stiffness reduction by force sensors and flexure hinges is quantified and different methods for compliance determination are compared.

9

Optimization of characteristic diagram based thermal error compensation via load case dependent model updates

Naumann Christian, Glänzel Janine, Dix Martin, Ihlenfeldt Steffen, Klimant Philipp

Journal of Machine Engineering

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2022

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Vol. 22, No. 2

43--56

EN

The compensation of thermal errors in machine tools is one of the major challenges in ensuring positioning accuracy during cutting operations. There are numerous methods for both the model-based estimation of the thermal tool center point (TCP) deflection and for controlling the thermal or thermo-elastic behavior of the machine tool. One branch of thermal error estimation uses regression models to map temperature sensors directly onto the TCP-displacement. This can, e.g., be accomplished using linear models, artificial neural networks or characteristic diagrams. One of the main limitations of these models is the poor extrapolation behavior with regard to untrained load cases. This paper presents a new method for updating characteristic diagram based compensation models by combining existing models with new measurements. This allows the optimization of the compensation for serial production load cases without the effort of computing a new model. The new method was validated on a 5-axis machining center.

10

Integration of OPC UA information models into Enterprise Knowledge Graphs

Weiss Arno, Ihlenfeldt Steffen

Journal of Machine Engineering

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2022

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Vol. 22, No. 2

138--147

EN

Building repositories of data relevant for enterprise operations requires harmonization of formats and semantics. OPC UA’s nodes-and-references data model shares basic elements with well-established semantic modeling technologies like RDF. This paper suggests the use of transformed OPC UA information models on the higher level of Enterprise Knowledge Graphs. It proposes good practice to integrate the separate domains by representing OPC UA servers as RDF-graphs and subsequently attaching them to Digital Twins embedded in Enterprise Knowledge Graph structures. The developed practice is implemented, applied to combine a server’s structure with an existing knowledge graph containing an Asset Administration Shell and released open source.

11

Accuracy assessment of articulated industrial robots using the Extended- and the Loaded-Double-Ball-Bar

Marwitz Johann August, Theissen Nikolas Alexander, Gonzalez Monica Katherine, Friedrich Christian, Hellmich Arvid, Archenti Andreas, Ihlenfeldt Steffen

Journal of Machine Engineering

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2022

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Vol. 22, No. 2

80--98

EN

This research paper outlines the methodology and application of geometric and static accuracy assessment of articulated industrial robots using the Extended Double Ball Bar (EDBB) as well as the Loaded Double Ball Bar (LDBB). In a first experiment, the EDBB is used to assess the geometric accuracy of a Comau NJ-130 robot. Advanced measuring trajectories are investigated that regard poses or axes configurations, which maximize the error influences of individual robot components, and, in this manner, increase the sensitivity for a large number of individual error parameters. The developed error-sensitive trajectories are validated in experimental studies and compared to the circular trajectories according to ISO 203-4. Next, the LDBB is used to assess an ABB IRB6700 manipulator under quasi-static loads of up to 600 Newton using circular testing according to ISO 230-4. The stiffness is identified from the loaded circular trajectories. Then, the stiffness is used to perform a reverse calculation to identify the kinematic errors on the path deviations. The concept is validated in a case study of quasi-static loaded circular testing using the LDBB compared to a Leica AT960 laser tracker (LT).

12

Systemy mocowania do obrabiarek

Świat Obrabiarek i Narzędzi

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2021

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R. 16, nr 1

13

Systemy mocowania do obrabiarek

Świat Obrabiarek i Narzędzi

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2021

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R. 16, nr 2

26

14

Modułowa konstrukcja MAXXTURN 65 G2

Świat Obrabiarek i Narzędzi

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2021

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R. 16, nr 3

31

15

JUNKER wyznacza nowe trendy w produkcji wałów wirnikowych

Świat Obrabiarek i Narzędzi

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2021

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R. 16, nr 3

30

16

Development and verification of a high-precision laser measurement system for straightness and parallelism measurement

Xu Peng, Li Rui Jun, Zhao Wen Kai, Chang Zhen Xin, Ma Shao Hua, Fan Kuang Chao

Metrology and Measurement Systems

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2021

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Vol. 28, nr 3

479--495

EN

A laser measurement system for measuring straightness and parallelism error using a semiconductor laser was proposed. The designing principle of the developed system was analyzed. Addressing at the question of the divergence angle of the semiconductor laser being quite large and the reduction of measurement accuracy caused by the diffraction effect of the light spot at the long working distance, the optical structure of the system was optimized through a series of simulations and experiments. A plano-convex lens was used to collimate the laser beam and concentrate the energy distribution of the diffraction effect. The working distance of the system was increased from 2.6 m to 4.6 m after the optical optimization, and the repeatability of the displacement measurement is kept within 2.2 m in the total measurement range. The performance of the developed system was verified by measuring the straightness of a machine tool through the comparison tests with two commercial multi-degree-of-freedom measurement systems. Two different measurement methods were used to verify the measurement accuracy. The comparison results show that during the straightness measurement of the machine tool, the laser head should be fixed in front of the moving axis, and the sensing part should move with the moving table of the machine tool. Results also show that the measurement error of the straightness measurement is less than 3 m compared with the commercial systems. The developed laser measurement system has the advantages of high precision, long working distance, low cost, and suitability for straightness and parallelism error measurement.

17

Seamless and modular architecture for autonomous machine tools

Fleischer Jürgen, Puchta Alexander, Gönnheimer Philipp

Journal of Machine Engineering

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2021

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Vol. 21, No. 3

40--46

EN

In machine tools, existing solutions for process monitoring and condition monitoring rely on additional sensors or the machine control system as data sources. For a higher level of autonomy, it becomes necessary to combine several data sources, which may be within or outside of the machine. Another requirement for autonomy is additional computing power, which may be hosted on edge devices or in the cloud. A seamless and modular architecture, where sensors are integrated in smart machine components or smart sensors, which are in turn connected to edge devices and cloud platforms, provides a good basis for the incremental realisation of autonomy in all phases of the machine life cycle.

18

Operator integrated – concept for manufacturing intelligence

Wegener Konrad, Weikert Sascha, Mayr Josef, Maier Markus, Ali Akbari Vahid Ostad, Postel Martin

Journal of Machine Engineering

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2021

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Vol. 21, No. 4

5--28

EN

Increasing autonomy and sustainability are major goals in manufacturing. Main technological trends provide enablers for achieving these goals and need to be implemented and combined in manufacturing machinery in a suitable manner. The paper exposes a vision of modern manufacturing machines, where the complexity of manufacturing processes is handled within the manufacturing machine and a simplistic front end is presented to the operator, which means that major elements of operators’ tasks are fulfilled by the intelligence of the machine. Research vectors paving the ground for this concept from different points of view are then discussed. Research is presented on intelligent grinding, intelligent recognition and suppression of chatter, adaptive thermal and motion error compensation exploting also self-learning abilities. It is necessary to point out, that not only intelligent mastering of process and machine becomes more and more important but communications among machine tools enabling process chain overarching intelligent approaches and creating intelligent factories.

19

An approach to an intelligent scanning of the machine tool workspace

Marchewka Lukasz, Grudzinski Marek

Journal of Machine Engineering

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2021

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Vol. 21, No. 2

60--74

EN

Modern 3D scanners can measure the geometry with high accuracy and within a short time. In turn, currently produced CNC machine tools allow for very accurate manufacturing; however, processes beyond the machining cycle remain time-consuming. This paper presents the idea and experimental tests of the scanning system in the CNC machine, which allows to speed up on-machine measurements, align clouds of 3D data points with an accuracy close to that of the machine itself, and finally set the workpiece coordinate system for machining. This modern approach is in line with Industry 4.0, combining the terms of data processing, machine vision, manufacturing automation, and human-machine interfaces. The future implementation of the proposed system as an interchangeable tool will allow performing autonomous measurements, inspection, and supervision of the workspace, without engaging the machine operator. The system calibration and experimental results using the industrial 3D scanner and CNC machine are described.

20

An effective data reduction model for machine emergency state detection from big data tree topology structures

Iaremko Iaroslav, Senkerik Roman, Jasek Roman, Lukastik Petr

International Journal of Applied Mathematics and Computer Science

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2021

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Vol. 31, no. 4

601--611

EN

This work presents an original model for detecting machine tool anomalies and emergency states through operation data processing. The paper is focused on an elastic hierarchical system for effective data reduction and classification, which encompasses several modules. Firstly, principal component analysis (PCA) is used to perform data reduction of many input signals from big data tree topology structures into two signals representing all of them. Then the technique for segmentation of operating machine data based on dynamic time distortion and hierarchical clustering is used to calculate signal accident characteristics using classifiers such as the maximum level change, a signal trend, the variance of residuals, and others. Data segmentation and analysis techniques enable effective and robust detection of operating machine tool anomalies and emergency states due to almost real-time data collection from strategically placed sensors and results collected from previous production cycles. The emergency state detection model described in this paper could be beneficial for improving the production process, increasing production efficiency by detecting and minimizing machine tool error conditions, as well as improving product quality and overall equipment productivity. The proposed model was tested on H-630 and H-50 machine tools in a real production environment of the Tajmac-ZPS company.