New Publications

[ 1 ] (2021), "Modelling and prevention of meshing interference in gear skiving of internal gears", Forschung im Ingenieurwesen, vol. 85, [30.11.-1].
Gear skiving is a highly productive process for machining of internal gears which are required in large quantity for electric mobility transmissions. Due to the complex kinematics of gear skiving, collisions of the tool and workpiece can occur during the process. Models exist to check for collisions of the tool shank or collisions in the tool run-out. While these models are sufficient for the process design of external gear skiving, at internal gears meshing interfer-ences between tool and workpiece can appear outside the contact plane on the clearance face of the tool. To test for meshing interference requires comprehensive assessment of workpiece, tool and process kinematics. Currently, this is often done by time consuming CAD-simulation. In contrast, this paper presents an automated geometrical model for the analysis of meshing interference. The test for collisions is thereby performed along the whole height of the tool and especially includes constructive clearance angles and eccentric tool positions. The model is developed for user-friendly implementation and practical applications. The model for avoiding meshing interference in gear skiving is validated on two different pro-cess applications. In doing so, influences of the tool and process design on the interference situation are investigated, compared and discussed. Furthermore this new approach enables the prevention of meshing interference or tooth tip collisions in the early tool design by adjust-ing the process kinematics or the tool design itself. The maximal viable tool height can be quantified and recommendations for improving the clearance face situation are suggested.

[ 2 ] (2021), "A new approach for local cutting force modeling enabling the transfer between different milling conditions and tool geometries". Elsevier, pp. 138-143.
The modeling of modern high performance machining with intermittent cut and varying effective cutting parameters requires a flexible local cutting force prediction. Due to complex tool geometries and varying cutting conditions without a rigid reference system new approaches for the local cutting force decomposition are applied, investigated and compared. The force decompositions are based on the separation of the effective cutting speed into normal and tangential components to adequately consider the locally acting mechanisms. Regression models based on the effective cutting parameters are defined to compare and validate the local force decomposition. A high feed peripheral milling experiment with specific cutting force measurement is presented to develop the regression models. An extensive cutting force database for AISI 5115 is created by tool geometry and process control variable variations. The effective cutting conditions are calculated through geometric penetration simulation. Considering the tool deflection in the simulation achieves a high regression accuracy even with low chip thicknesses. This is especially important for the cutting force prediction of finishing processes. The resulting regression cutting force models and force decompositions are rated based on the applicability to different tool geometries, like a ball end mill.

[ 3 ] Kupzik, D.; Spiller, Q.; Coutandin, S. & Fleischer, J. (2020), "Additive Manufacturing of Metal Components using the ARBURG freeformer System". 25.-26.6.2020.
Metal powder injection molding is a manufacturing technology that is characterized by the near-net-shape production of geometrically complex components with outstanding mechanical properties. In this process, green bodies are molded with an injection molding machine, which are then debound and sintered. Due to the necessary tool form, an economic production is only reasonable from correspondingly high quantities. Additive manufacturing processes offer the possibility of economic production from piece number one. ARBURG plastic freeforming represents an additive manufacturing process which uses commercially available plastic granulate for the production of components. This molding process offers the potential to use feedstocks from the metal powder injection molding sector to manufacture green parts. This makes it possible to economically produce metal components with comparable properties to metal powder injection molding from a quantity of 1 piece. In this presentation, the process and the interrelationship between the process parameters and the mechanical properties of the component are presented. The temperature of the nozzle, temperature of the build volume and printing speed are optimized regarding mechanical properites. The second presented goal of optimization is to increase the service life of the nozzle. An increase by 255% could be achieved by tempering and plasma nitriding the nozzle.

[ 4 ] (2021), "Numerical design of rotationally molded composite tie rods ", Composite Structures, [30.11.-1].
Rotational molding constitutes a promising manufacturing technology for rotationally symmetric components made of thermoset matrix with continuous fiber reinforcement. The present study deals with the numerical analysis of a rotationally molded composite tie rod with metallic load introduction elements. For this purpose, the adhesive joint between carbon fiber reinforced plastic and metallic load introduction element was investigated in more detail. Different geometries of a spew fillet were evaluated to reduce the stress peaks occurring at the ends of the overlap. A design of experiments was used to determine the influence of the different parameters. An optimized geometry was derived and compared with a reference in terms of stress distribution. Subsequently, test specimens were rotationally molded and mechanically tested. The results of the study show that the maximum stresses within the adhesive layer can be reduced with an optimized spew fillet, and thus a higher mechanical tensile load of the composite tie rod can be achieved.

[ 5 ] (2021), "Agile Batteriezellfertigung als Antwort auf volatile Märkte und Technologien Agile Battery Cell Manufacturing as Response for Volatile Markets and Technologies", wt online, pp. 486 - 489. [30.11.-1].
Die industrielle Batteriezellfertigung ist geprägt durch starre Produktionssysteme für die Massenfertigung. Die Fertigung anwendungsspezifischer Zellen im geringen bis mittleren Stückzahlsegment erfolgt derzeit kostenintensiv in einer Werkstattfertigung. Basierend auf standardisierten Roboterzellen und einer flexiblen Steuerungsarchitektur wird ein Konzept zur hoch automatisierten material-, format- und stückzahlflexiblen Batteriezellfertigung beschrieben. Agile Battery Cell Manufacturing as Response for Volatile Markets and Technologies Industrial battery cell production is characterized by rigid production systems for mass production. The production of application-specific cells in a low to medium quantity segment is currently performed by cost-intensive workshop production. Based on standardized robotic cells and a flexible control architecture, a concept for highly automated battery cell production that is flexible in terms of material, format and number of units is described.

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