Special Interest Group Meeting: Thermal Issues
26 – 27 February 2020, Aachen, DE

Tours

Delegate Registration

Laboratory Tours of the Laboratory for Machine Tools and Production Engineering (WZL) of RWTH Aachen, and Fraunhofer Institute for Production Technology (IPT)

Delegates will have the opportunity to visit multiple test rigs located at both Manfred-Weck-Haus (WZL), and Fraunhofer Institute for Production Technology (IPT) as part of the laboratory tours.

The 6 test rigs available to visit are detailed in the table below. Please note that these will not be guided tours.  Delegates will be free to move between rigs during the allocated time, visiting as many rigs as of interest.

At each of the rigs, there will be representatives from either WZL or IPT who will be on hand to provide guiding instructions and to answer any questions.

Machine Hall
Test rig
Description
Topics
Measurement of thermal influences in production equipment, process and product
Modelling and model reduction techniques
Compensation and correction of thermal effects
Thermo-energetic design
Temperature Measurement & Control
IPT
Online correction of thermo-elastic errors on a 3-axis machining centre with integral deformation sensors (IDS)
A novel approach is developed at Fraunhofer IPT, which measures the deformation of the machine structure and predicts the TCP dislocation. The sensors, comprised of thermally neutral rods made of CFRP and position transducers, enable the detection of the integral elongation along their axis with ≤ 1 µm uncertainty. A simple mechanical model calculates the TCP dislocation with up to 90% prediction accuracy without data training. This correction approach offers a simple Plug&Play solution to improve the machine tool accuracy.
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IPT
Hybrid correction of thermo-elastic errors on a 5-axis machine tool with IDS and dynamic R-test re-calibration
The correction method based on the aforementioned IDS has been combined with the power of machine learning with the help of the R-test procedure. The objective is to predict the thermal behaviour of 5-axis machine tools with low retrofit and modelling effort, despite of the complexity of the kinematics and the overlapping deformations and inclinations. The prediction that the mechanical model creates is re-calibrated every time a dynamic R-test measurement is set to measure the current TCP dislocation. This minimizes the prediction even further and ensures a reliable correction that remains unchanged from one work piece to the next one in large-series production lines.
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WZL, MWH
Volumetric measurement of load dependent thermo-elastic deformations
The process loads are simulated by a mechanical load unit. These applied loads are measured by a method using four laser tracers. Thereby, 17 geometric errors and their variations due to the thermo-elastic machine behaviour can be measured with a small measurement uncertainty. The large number of errors and their assignment to the machine axes enable a wide range of opportunities for root cause analyses.
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WZL, MWH
Analysis of the thermo-elastic operating behaviour of ball screws
The newly developed test bench at the WZL is used to investigate the thermo-elastic behaviour of ball screws. In addition to temperatures, the load-displacement behaviour can be measured. The test bench allows applying axial forces, as they occur in real machine tools, during motion of the axis. Besides investigating thermo-elastic effects metrologically, a new white-box calculation method considering contact conditions is developed and validated with the test bench. Exemplary calculation results are contact angles, normal forces and contact pressures for different axial loads, feed velocities and thermal states of the ball screw.
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WZL, MWH
Online monitoring of thermo-mechanical effects in a motorized milling spindle
Due to the central position of the main spindle of machine tools, its operating conditions are particularly important for productive and precise manufacturing. Besides understanding thermally affected mechanisms, being able to predict the operating conditions accurately is of major significance. Thus, an approach for simulating thermal effects in spindles online was developed at WZL. By combining live data with deep technical domain knowledge, the entire operations spectrum of the spindle can be covered. As a use case, an 18 kW motorized milling spindle can be applied with external loads on a test bench while monitoring thermo-mechanical effects at the same time.
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WZL, MWH
Live presentation of an ANSYS-extension for simulation and model order reduction of machine tool models
The newly developed approach to simulate the thermal behaviour of complete machine tools is wrapped in an ANSYS-Workbench-extension. To speed up simulations in the design and production process of machine tools, several model order reduction techniques are incorporated. The complete workflow for a simple example-machine will be shown live. Furthermore, the benefits and drawbacks of the different model types (FE-model, reduced order model) applied to simulate the thermal behaviour will be discussed.
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