Methods for Determining Thermal Errors in Machine Tools by Thermo-Elastic Simulation in Connection With Thermal Measurement in a Climate Chamber

Geist, Alexander; Naumann, Christian; Glänzel, Janine; Pütz, Matthias

doi:10.17973/mmsj.2023_06_2023049

Cited by 3 publications

(4 citation statements)

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“…On the right side of the diagram, the relative displacement between tool center point and the workpiece side is shown for an example point. Further details regarding the experimental studies in the climate chamber and the validation of the models are presented in the literature [46]. ambient temperature, room-temperature-controlled cooling lubricant temperature, but also machining processes were included.…”

Section: Tool Axis Linear Travel Axes Rotatory Table Axesmentioning

confidence: 99%

Correction of Thermal Errors in Machine Tools by a Hybrid Model Approach

Friedrich,

Geist,

Yaqoob

et al. 2024

Applied Sciences

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Thermally induced position errors are one of the main error sources on the workpiece caused by the behavior of the machine tool. In today’s industrial environment, the correction of thermal errors is usually based on simple regression approaches, where the characteristic diagrams for correction are generated experimentally. The performance of these approaches is only valid for the corresponding load regimes, which often results in insufficient correction quality in practical applications. Consequently, there is only a limited benefit or even a deterioration in machine behavior if the correction characteristic is based on an inapplicable load case compared to the initial experiment. Simulation-generated characteristic diagrams using finite element models solve this disadvantage, but do not answer the question about the choice of the right characteristic matching the current load situation, and, in addition, calculate very slowly. Structural model-based correction using reduced models, on the other hand, calculates quickly, but requires a high modeling effort for accurate correction. The approach, presented in this contribution, combines simulation-generated characteristic diagrams and a structural model-based decision algorithm for a new hybrid model in order to select the appropriate characteristic diagram for the present load situation in the control system. This paper presents the simulative characteristic diagram generation by a finite element model validated by experiments in a climate chamber and a validated structural model including the concept for the decision algorithm.

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Section: Tool Axis Linear Travel Axes Rotatory Table Axesmentioning

confidence: 99%

Correction of Thermal Errors in Machine Tools by a Hybrid Model Approach

Friedrich,

Geist,

Yaqoob

et al. 2024

Applied Sciences

Self Cite

View full text Add to dashboard Cite

show abstract

“…The simulations for this second model were transient FEM simulations with active cooling systems but again without any other internal influences like waste heat from motors and guides. See Chapter 3 and [22] for details on the simulation model and its parametrization and validation measurements.…”

Section: Compensation Model Structurementioning

confidence: 99%

“…Model training was done using FEM simulations, which were parametrized and validated using measurements in a climate chamber [22]. Using such a chamber is not absolutely necessary but it significantly improves the quality of the measurements and thereby the resulting model parametrization.…”

Section: Case Study: Thermal Error Compensation Of the Dmu 80 Evomentioning

confidence: 99%

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Handling Ambient Temperature Changes in Correlative Thermal Error Compensation

Naumann,

Alexander,

Putz

2023

Journal of Machine Engineering

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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).

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Concept of Integrating a Hybrid Thermal Error Compensation Into an Existing Machine Tool Control Architecture

Geist,

Yaqoob,

Friedrich

et al. 2024

Journal of Machine Engineering

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Thermal error compensation via a numeric control (NC) system is a proven option for upgrading the precision of machine tools. The main advantage is the generally cost-effective application, as no changes to the machine design are necessary. Since modern machine tools are equipped with standard numeric controls along with additional functions and integrated temperature sensors in the machine, compensation methods such as a characteristic diagram (CD) based compensation can be implemented. To increase the applicability and reliability of this CD regression method, a hybrid model approach with a virtual thermo-elastic finite element (FE) machine model and a real-time computable structural model of a machine tool was developed. The structural model uses model order reduction to calculate the current load case in real-time using continuously recorded machine data (motor current, axis position, temperatures). It acts as a virtual monitoring application to check, whether the current machine condition still matches the current CD based prediction. If the current load case is not suitable to the active CDs or any other stored CDs, the generation of new CDs is automatically triggered. In this article, the integration of the hybrid compensation method using an FE model and a structural model of a machine tool is methodically demonstrated. The main focus is on the integration of different software and hardware architectures and their interaction.

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Methods for Determining Thermal Errors in Machine Tools by Thermo-Elastic Simulation in Connection With Thermal Measurement in a Climate Chamber

Cited by 3 publications

References 0 publications

Correction of Thermal Errors in Machine Tools by a Hybrid Model Approach

Correction of Thermal Errors in Machine Tools by a Hybrid Model Approach

Handling Ambient Temperature Changes in Correlative Thermal Error Compensation

Concept of Integrating a Hybrid Thermal Error Compensation Into an Existing Machine Tool Control Architecture

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