Design And Validation of A Sheet Metal Clamping System For Additive Manufacturing and Post-Processing

Automated clamping for post-processing of mass-customized parts is a challenging step in the laser powder bed fusion (LPBF) process chain. In this study, a novel modular sheet metal clamping system was developed that uses disposable sheet metal profiles as a universal interface for the LPBF, robotic handling, and milling processes. Based on a fundamental investigation of hybrid additive manufacturing, the sheet metal clamping system was designed to use the same interface for the LPBF and milling processes. Subsequent an end-to-end validation was performed for the entire process chain. The concept of the sheet metal clamping system gives milling tools access to a part on five to six sides. Further, the part can be accessed from the top and bottom sides, and simplifying the removal of LPBF supports. No clamping forces are induced in the LPBF part, which is especially important for filigree structures. The sheet metal clamping system’s underlying concept could be adapted to automating the LPBF process chain for applications such as prosthetic dentistry.

Sheet Metal Profiles with Variable Height: Numerical Analyses on Flexible Roller Beading

In the spirit of flexible manufacturing, the novel forming process “flexible roller beading” was developed, which allows the incremental production of height-variable sheet metal profiles. After designing the process and realizing a test facility for flexible roller beading, the feasibility was experimentally shown. The following step addresses the expansion of the process limits. With this aim, the mechanical behavior of the sheet metal during the process was investigated by means of FEA. Due to the variable cross-section development of the sheet metal profile, a multidimensional stress distribution was identified. Based on the present state of stress and strain, conclusions about the origin of appearing defect formations were drawn. Observed defects were sheet wrinkles as a result of compressive stresses in the profile flange and material thinning in the profile legs and bottom due to unintendedly exceeding tensile stresses. The influences of the forming strategy as well as tool- and workpiece-side variations on the quality of the manufacturing result were investigated. From the results of the analyses, measures to avoid component failure were derived. Given all the findings, guidelines were concluded that are to be considered in designing the forming sequence. With the insights into the occurring processes and the mastery of this novel forming process, important contributions are made to its industrial suitability. The approach of lightweight and load-oriented component design can be extended by realizing new families of sheet metal profiles. With respect to Industry 4.0, on-demand manufacturing is increasingly required, which is why flexible roller beading is of substantial relevance for the industrial sheet metal production.

Leichtbauprofile durch flexibles Rollsicken*/Lightweight profiles by flexible roller beading – A novel forming technology for the production of sheet metal profiles with variable cross-sections

Im Sinne des Wandels der konventionellen Massenproduktion hin zur seriellen Maßanfertigung wurde das Verfahren „Flexibles Rollsicken“ entwickelt, welches die kontinuierliche Fertigung von Profilen mit veränderlicher Höhe erlaubt. Im Folgenden werden die Funktionsweise und Auslegungskriterien dieses neuartigen Umformverfahrens erläutert. Des Weiteren wird gezeigt, wie der Einsatz von durch flexibles Rollsicken hergestellten Halbzeugen die Umformgrenzen in nachgeschalteten Prozessen erweitern kann.   In the spirit of the change from conventional mass production to mass customization, the process “flexible roller beading” has been developed, which enables the continuous production of profiles with variable height. The following explains the operating principle and process design criteria. Furthermore, it is shown how the use of semi-finished products produced by flexible roller beading can expand the forming limits in downstream processes.

Concept of an Automatic Integration of Parts Measurement Data Into Feature-Based CAD Models

This paper introduces a concept to integrate measurements data into feature-based 3D CAD models. The concept focuses on its application in the measurement of bifurcated sheet metal profiles. For that, an interface to read and import this data into the CAD system is developed. Since the measurement data is stored as a point cloud, further data processing (reverse engineering) is necessary to recreate the work piece shape in the CAD system. If the measured work piece model and the CAD model of the design piece are available, an automated comparison of the defined dimension takes place. The result is a notification in the CAD model indicating which dimension deviates from the target values. Use-cases are elaborated for integrating the concept in the product development process. To implement this concept, an experimental setup is built up consisting of a measurement system and 3D CAD system. The COPRA ProfileScan Desktop is used to measure the profile. Siemens NX 11 is the chosen CAD system. Based on this setup, the concept is validated on a manufactured profile.

Draw Bending of Load-Adapted Sheet Metal Profiles

The draw bending process represents an alternative for the flexible and inexpensive production of open sheet metal profiles. This paper introduces the draw bending process with its functional principle and specifies the most important characteristics. It includes the key results of several research projects dealing with draw bending to prove the applicability of this technique to produce customized profiles.

Flexible Draw Bending of Profiles

The technology of draw bending represents an alternative to produce flexible load-adapted sheet metal profiles. In addition to the adaptability of profile configuration low machine costs and an uncomplicated system control make this a very flexible production method. Hence it is particularly suitable for the production of profiles in small batch series or the fabrication of prototypes.