Energy consumption analysis of robot based SPIF

Part of: Seliger, Günther (Ed.): Innovative solutions : proceedings / 11th Global Conference on Sustainable Manufacturing, Berlin, Germany, 23rd - 25th September, 2013. - Berlin: Universitätsverlag der TU Berlin, 2013. - ISBN 978-3-7983-2609-5 (online). - http://nbn-resolving.de/urn:nbn:de:kobv:83-opus4-40276. - pp. 131–136.Production processes, as used for discrete part manufacturing, are responsible for a substantial part of the environmental impact of products, but are still poorly documented in terms of environmental impact. A thorough analysis of the causes affecting the environmental impact in metal forming processes is mandatory. The present study presents an energy consumption analysis, including a power study of Single Point Incremental Forming (SPIF) processes using a 6-axes robot platform. The present paper aims to investigate whether the fixed energy consumption is predominant or negligible in comparison to the actual forming operation. Power studies are performed in order to understand the contribution of each sub-unit towards the total energy demand. The influence of the most relevant process parameters, as well as the material being processed and the sheet positioning, with respect to the power demand are analysed

Numerical analyses of the influence of a counter punch during deep drawing

In the automotive sector, the demand for high crash safety and lightweight construction has led to an increased use of steels with higher strengths. However, the rising number of varying materials with different strengths and ductilities lead to an increasing complexity in productionmaking it more challenging to ensure robust processes. Therefore, the focus of current researches still lays on the further development and extension of forming processes to enable high productivity and reliable production. A powerful tool for an efficient optimisation and extension of forming processes is the Finite Element Method (FEM), which offers time-and cost saving potentials in the design phase. In deep drawing, the use of a counter punch offers the possibility oextending the process limits. By superimposing compressive stresses on the workpiece, the initiation of cracks can be delayed, thus higher drawing ratios can be achieved. The aim of this research is therefore the numerical investigation of a deep drawing process with a counter punch to analyse the influence on the crack initiation and identify optimisation potentials for the processFor this cause, the applied force as well as the position and geometry of the counter punch are varied and the influence on fracture initiation is evaluated. It is found that the applied force on the counter punch is the major influencing factor for crack initiation. Furthermore, it was concluded that the contact between the counter punch and the workpiece should be applied as soon as the bottom of the cup is shaped. A further improvement can be achieved if the counter punch is geometrically adapted to the bottom of the workpiece

Evaluating material failure of AHSS using acoustic emission analysis

Driven by high energy prices and strict legal requirements on CO2 emissions, high-strength sheet steel materials are increasingly gaining importance in the automotive industry regarding electric vehicles and their battery range. Simulation-based design of forming processes can contribute to exploiting their high potential for lightweight design. However, previous studies show that numerical simulation with conventional forming limit curves does not always provide adequate prediction quality. Failure models that take the stress state into account represent an alternative prediction method for the shear-dominated failure, that frequently occur in high-strength steels during forming. The failure behaviour of the sheet materials can be determined by different specimen geometries for a wide range of stress states and by using an optical measurement system to record the local strain on the surface of the specimen at the location of failure. However, for many high-strength steels, critical damage or failure initiation already occurs inside the specimen. Therefore, a method is needed that allows detection of failure initiation at an early stage before the crack becomes visible on the surface of the specimen. One possible method is the use of acoustic emission analysis. By coupling it with an imaging technique, the critical strains leading to failure initiation inside the specimen can be determined. In the presented paper, butterfly tests are performed for a wide range of stress states and measured with an optical as well as an acoustical measurement system. The tests are analysed regarding the failure initiation using a mechanical, optical as well as acoustical evaluation method and compared with each other

Development of polygon forming processes for aerospace engineering

The focus of this research lays on the further development of the Polygon Forming Technology, which is already successfully used for cold forming components in the aerospace industry. One example is the fuselage shell of the Airbus Beluga XL. According to the current state of the art it is possible to incrementally form large cylindrical or conical fuselage components by Polygon Forming. With the use of so-called infills, the Polygon Forming process can also be used to form components with pockets milled in the initial plane state. The limits of this technology exclude the creation of spherical geometries, such as those used in the front or rear fuselage sections of aircrafts. Presently, such components are produced by more complex stretch forming processes, which result in a considerable amount of scrap. In this work, a tool is developed to replicate the Polygon Forming process on experimental scale at the Institute of Forming Technology and Machines (IFUM) for materials commonly used in aerospace engineering. In addition, a downscaled pre-test tool is developed to investigate different tool geometries for incremental spherical forming inexpensive and easy according to the method of rapid prototyping

Convenio Específico con la Universidad de Palermo, Italia.

El presente acuerdo de colaboración, busca crear y desarrollar un sistema de intercambios académicos, entre ambas Instituciones, con el espíritu de la cooperación internacional para la formación