Efficient simulation of complex capillary effects in advanced manufacturing processes using the finite volume method

The accurate representation of surface tension driven flows in multiphase systems is considered a challeng- ing problem to resolve numerically. Although there have been extensive works in the past that have presented approaches to resolve these so called Marangoni flows at the phase boundaries, the question of how to efficiently resolve the interface in a universal and conservative manner remains largely open in comparison. Such problems are of high practical relevance in many manufacturing processes, especially in the microfluidic regime where capillary effects dominate the local force equilibria. In this work, we present a freely available numerical solver based on the Finite Volume Method that is able to resolve arbitrarily complex, incompressible multiphase systems with the mentioned physics at phase boundaries. An efficient solution with respect to the number of degrees of freedom can be obtained by either using high order WENO stencils or by employing adaptive cell refinement. We demonstrate the capabilities of the solver by investigating a model benchmark case as well as a single track laser melting process that is highly relevant within laser additive manufacturing

Finite element based compression and volumetric load analysis for grasped objects

Grasp evaluation criteria are not only restricted to the planning stage but also while the grasp is performed and are included as optimization parameters to select a suitable grasp. For fragile objects, a strength analysis is needed to determine damages of the object through an end effector. To evaluate this criterion, the emerging residual stresses for various grasping positions must be calculated. In this work we present a Finite Element based mechanical load analysis for a set of grasping positions. Because the grasping positions have a high spatial distribution the setup is dynamic and adaptable to various input parameters. Therefore, boundary conditions are automatically set through auxiliary objects to determine the consequences of clamping forces and volumetric loads on the grasped object. Through the inclusion of all possible mechanical loads we are able to perform a fully comprehensive strength analysis. Our evaluation for a reference object showed comparable displacements (<0.1%) to a manually specified strength analysis in Ansys Structural while significantly reducing the time to set up the strength analysis

Modelling of microstructures during in-situ alloying in additive manufacturing for efficient material qualification processes

In this work, a numerical simulation framework is presented based on the Phase Field Method that is able to capture the evolution of heterogeneous metallic microstructures during solidification. The involved physics can prove especially useful when studying not only systems undergoing thermal gradients, such as in homogeneous systems, but also in conditions that exhibit stark spatial gradients, i.e. when these inhomogeneities are present even on a mesoscopic scale. To illustrate the capabilities of the model, in-situ alloying of a High Entropy Alloy during Laser Powder Bed Fusion is investigated as an exemplary use case. The resulting digital twin is expected to shorten development times of new materials as well as cut down on experimental resource needs considerably, therefore contributing to efficient material qualification processes.Comment: 12 pages, 4 figures, submitted to ASIM Simulation in Produktion und Logistik 2021, Erlange

Automatic end tool alignment through plane detection with a RANSAC-algorithm for robotic grasping

Camera based grasping algorithms enable the handling of unknown objects without a complete CAD model. In some scenarios, the captured information from a single view is not sufficient or no grasp is possible. For these cases, the precise realignment of the gripper is difficult because a suitable rotation is part of an infinite solution space. In this paper, we propose a framework which automatically identifies correct rotations from point clouds to adjust the gripper. We validate our approach in a virtual environment for a parallel jaw gripper with multiple isolated and grouped industrial objects

Cost estimation approach of a digital twin implementation in industry

In the context of Industry 4.0, the concept of the digital twin provides an approach, which supports companies by finding solutions for complex problems. Due to the novelty of the technology, companies face certain issues regarding the implementation, like the uncertainty of the arising costs. By introducing a methodology in this publication, an estimation approach for the costs of a digital twin implementation is expounded. Through the assessment of the actual digitization level of a company previous relevant achievements are considered in the cost estimation. Furthermore, the methodology is implemented in an Excel tool and validated within an industry use-case

Method for evaluating the monetary added value of the usage of a digital twin for additive manufacturing

By combining the additive manufacturing (AM)-process with digital concepts, such as the digital twin (DT) or the digital part file (DPF), the competitiveness of additive manufacturing is increased. A quantitative approach to evaluate the usage of a DPF in AM will be introduced within this paper. The focus is set on the production as an early lifecycle-phase, which means that the AM-production process gets analyzed regarding potential advantages of using a DPF. These advantages are transferred into a monetary value with our approach. By calculating the total costs of the DPF, a monetary overall value is obtained

Method for identifying and evaluating the fields of application of a digital twin

In the context of Industry 4.0, digital technologies and concepts are becoming more and more important in companies, as they can provide solutions to current challenges. The digital twin in particular can be used in various fields of application and thus create added value. However, the variety of different application possibilities as well as the difficult evaluation of the added value of the digital twin poses great challenges for companies. This publication therefore presents a method that offers companies a structured approach to identifying and subsequently evaluating possible uses of the digital twin based on their digital maturity. First, the digital maturity of a company is determined by means of a point-based questionnaire and a suitable identification method is proposed based on the result of the digital maturity. If a field of application could be identified with the proposed method, it is evaluated by a self-developed "Digital Twin Canvas" and, depending on the field of application, by a suitable simulation. By applying the method in various companies from different sectors, the method's functionality has been validated