Session 8 Future of Manufacturing II

Thursday, 12.11.2020, 16:20-18:00 o'clock


Tatyana Sheveleva: Development of a domain-specific Ontology to support Research Data Management for the Tailored Forming Technology

16:20-16:40 o'clock

(Paper ID: 1137)

The global trend towards the comprehensive digitalisation of technologies in product manufacturing is leading to radical changes in engineering processes and requires a new extended understanding of data handling. The amount of data to be considered are becoming larger and more complex. Data can originate from process simulations, machines used or subsequent analyses, which together with the resulting components serve as a complete and reproducible description of the process. Within the Collaborative Research Centre “Process Chain for Manufacturing of Hybrid High Performance Components by Tailored Forming”, interdisciplinary work is being carried out on the development of process chains for the production of hybrid components. The management of the generated data and descriptive metadata, the support of the process steps and preliminary and subsequent data analysis are fundamental challenges. The objective is a continuous, standardised data management according to the FAIR Data Principles so that process-specific data and parameters can be transferred together with the components or samples to subsequent processes, individual process designs can take place and processes of machine learning can be accelerated. A central element is the collaborative development of a domain-specific ontology for a semantic description of data and processes of the entire process chain.

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Miriam Handrup: Piezo-actuated hybrid tool for the micro structuring of cylinder liners in an energy-efficient process chain

16:40-17:00 o'clock

(Paper ID: 1175)

Automotive traffic is one of the largest drivers of greenhouse gas emissions in Europe. In order to achieve energy savings both, during the process and during the use phase of passenger cars, the powertrain components and their process chains will be optimized as part of the “Powertrain 2025” project. For this purpose, the implementation of an innovative process chain for the production of non-circular, microstructured and honed cylinder liners is being researched. Therefore, the paper introduces a new piezo-actuated hybrid tool, which was developed for the combination of non-circular turning and microstructuring of the cylinder liners in one tool. An integrated optical distance sensor measures after the process the workpiece geometry. This is used for quality control and as an input value for a process chain control that optimizes the process parameters and thus reduces the reject rate. After a short introduction of the new, energy-efficient process chain, the paper focuses on the concept and dimensioning of the new hybrid tool.

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Patrick Georgi: Fundamental investigation on the correlation between surface properties and acceleration data from a sensor integrated milling tool

17:00-17:20 o'clock

(Paper ID: 1109)

The detection, analysis, compensation, or even the targeted modification of workpiece surfaces of complex components plays an essential role in the machining of metals. The surface properties of e.g. an aircraft engine component or sheet metal draw die have a significant influence on the usage and durability of the component. In order to be able to process the free-form surfaces typical of these components, the used end-milling tools need to be long-cantilevered and slender. Because of their less rigid construction, these end-milling tools are very susceptible to process-induced vibration. That, in turn, affects the component surface negatively and requires reworking or even new production of the workpiece.

Today, the characterisation of the component surfaces is carried out downstream and partly by extensive quality investigations. A 100% inspection of the entire surface is usually not carried out. To be able to influence the surface properties during machining and thus to make the process more efficient, a sensor integrated end-milling tool has been developed. This tool continuously records the data from an acceleration sensor to refer back to the milled component surface and document the results in a database. The significant advantage of the sensor integrated end-milling tool is the high sensitivity due to the accelerometer installed close to the tool centre point. The work presented here focuses on fundamental investigations of the correlation between the acceleration data acquired from the sensor and the surface properties achieved. The paper also shows that the acceleration data is a decent reflection of the measured surface properties. Besides, the investigations show that the acceleration data of the sensor integrated end-milling tool are suitable for realising a specified surface conditioning. Furthermore, an outlook is given which shows how a process control can accomplish an adjustment of the surface properties by adjusting the spindle speed and the feed force of the machine tool.

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Robert Wegert: Determination of thermo-mechanical quantities with a sensor-integrated tool for single lip deep hole drilling

17:20-17:40 o'clock

(Paper ID: 1108)

To adjust the subsurface workpiece properties, such as hardness and residual stresses as well as surface quality, machining processes are often followed by forming, peening or heat treatment processes. An appropriate setup of the machining process can adjust the desired properties. The work presented here is part of an interdisciplinary research project in the framework of the priority program “Surface Conditioning in Machining Processes” (SPP 2086) of the German Research Foundation (DFG). This research project has the main objectives to determine the actual thermo-mechanical state of the surface and subsurface in single lip deep hole drilling during the process by means of a sensor-integrated tool as well as to control the process parameters to achieve the desired workpiece properties.

Preliminary test series are related to the determination of the thermo-mechanical boundary conditions with thermal, material and machining models. From the obtained results, the requirements concerning the sensor-integrated tool can be derived. Further steps include the development of a tool for the in-process determination of the real cutting conditions, the selection and integration of sensor systems as well as the correlation of process states with workpiece conditions. The single lip deep hole drilling tool will be equipped with sensor systems for the acquisition of temperatures, forces, torques and vibrations close to the affected zone. In particular, for the determination of the process temperature close to the cutting zone, a multi-sensor approach was chosen. Effects on the workpiece can then be investigated using material simulations. The elaboration of a control strategy and its implementation in a deep hole drilling machine will finalize the current project phase. The final goal is that the required workpiece surface and subsurface properties can be controlled based on measurement and simulation data.

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Eike Wnendt: Deflection compensation on a force sensing mobile machine tool

17:40-18:00 o'clock

(Paper ID: 1199)

Machining of large parts with a mobile machine tool results in significant savings of time, energy and transportation costs caused by moving large parts to the machine's location. The mobile machine tool can easily be transported to the larger work-piece and is able to crawl discontinuously along the surface to the desired operation spot. This allows flexible machining of large parts at reduced costs. Due to the smaller and lightweight structure of mobile machines, stiffness and accuracy are key topics regarding machining tasks.

Within this paper a model based deflection compensation for a mobile machine tool prototype is presented. The model compensates the deflection of the tool centre point (TCP) based on strain gauge measurements at the machines foot modules. The measured strains at each foot are used to calculate pose dependant gravitational forces as well as disturbance forces. These forces are then passed to the model. Hence, the model reconstructs the deflection of the TCP based on the measured forces at the foot modules.

Additionally, these sensory foot modules fix the machine on the work-piece surface while machining or crawling along the surface. The adhesive forces are applied through vacuum cups. Due to the flexible material of the vacuum cups, the machines lower mechanical stiffness has to be regarded within the model, too. However, the focus of the compensation lies on the pose dependant compliance of the X- and Y-axis.

Beside the model based compensation algorithm, the paper gives insights on the design of the sensory foot modules as well as genuine measurements on a prototype to validate deflection compensation. The measurements compare the calculated forces of the sensory foot modules to a force sensor mounted at the TCP. Furthermore, a laser interferometer was used to gain high precision displacement measurements for model validation.

The final comparison of the measured and predicted displacement showed high congruence in Z-direction for a load in the same direction. 95% of the deflection could be reduced by predicting 430µm of a total of 450µm. On the downside, only 50% of the 500µm displacement for a load in Y-direction could be predicted. Hence, the model based compensation combined with the sensory foot modules is capable of reducing a major portion of the robots position error under load. In future, further detailing of the models degrees of freedom should enable a reduction of 95% in every direction.

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