Automated Import of XML-Files Containing Optimized Geometric Data to 3D-CAD-Models of Non-Linear Integral Bifurcated Sheet Metal Parts

Author(s):  
Thiago Weber Martins ◽  
Katharina Albrecht ◽  
Reiner Anderl

The Collaborative Research Centre 666 has the focus on researching fundamental new methods for the development of optimized products and production processes for integral bifurcated sheet metal parts. Technological innovations have been achieved with respect to new production processes such as linear flow splitting and linear bend splitting as well as to produce products with flexible profiles. The use of state of art product development methodologies can be applied but these are not optimized to deal with the high complexity of the requirements and properties of integral bifurcated sheet metal products. In order to deal with that complexity a new approach of a product development methodology, the algorithm based product development process, has been established. Within the scope of the algorithm based product development methodology a topology optimization, based on mathematical algorithms using product requirements information, is already applied in the conceptual steps of product development process. By using this methodological approach an optimized concept of bifurcated sheet metal can be determined. The results are stored as optimized geometric data in XML-format files. 3D-CAD-Models are generated based on these data. However the import of these data into 3D-CAD-Systems are not fully automated. The developed data model, from earlier works for linear flow splitting and linear bend splitting, does not take into account the variability of the profiles in the third-dimension. In addition the topology optimization does not provide production-orientated design requirements and therefore it does not take into account the production process limits (of linear flow splitting and linear bend splitting). Hence 3D-CAD-Models resulting from the optimized geometric data need to be adapted manually. Therefore new advanced approaches in terms of virtual product development tools need to be explored. This paper describes the development of an interface within the CAD-System Siemens NX which supports the automatic import of XML-files containing the optimized geometric data of non-linear integral bifurcated sheet metal in 3D-CAD-Models. The existing data model is extended considering the requirements of the developed interface in order to represent nonlinear bifurcated profiles. An approach of the interface using the described data model and the NX Open API is introduced and explained.

Author(s):  
Oliver Weitzmann ◽  
Reiner Anderl

Functional integration and resource utilization are a challenge in today’s product development. The selective utilization of surface properties for functional integration offers potentials which aren’t exhausted until now. Surface roughness is mostly considered in manufacturing and measurement but the product properties impacted by surface roughness are determined in the product development. So it is necessary to integrate and extend the information about surface roughness in the methods and models of the product development. Therefore an approach for the representation of surface properties in product development is evolved. Based on the classification of surface deviation and profile courses, a method for building a surface profile is explored and depicted in an object-oriented representation model. One example for the functional integration and the use of technology-induced properties are sheet metal parts with higher order bifurcation in integral style. A new massive forming technology called linear flow splitting enables the manufacturing of sheet metal parts with higher order bifurcation in integral style. Within this manufacturing process, the material properties change heavily. Considering these changes in the product development, the representation model is needed to ensure the functionality. The model is used for generation a typical surface resulting from a linear flow splitting process.


Author(s):  
Thiago Weber Martins ◽  
Reiner Anderl

The algorithm-based product development process applies mathematical optimization tools in the conceptual steps of the product development process. It relies on formalized data such as initial loads and boundary conditions to find the best product solution for optimized bifurcated sheet metal parts. Previous research efforts focused on the automation of CAD modeling steps. Current algorithms are able to generate the CAD models of optimized bifurcated sheet metal products automatically, however, they are rough with low-level of detail and abstraction. Consequently, CAD models are embodied and detailed manually in a partly iterative and time-consuming process to include parameters, constraints and design features. Hence, this paper introduces feature recognition and parametrization methods for the algorithm-based product development of bifurcated sheet metal products. It proposes the inclusion of a pre-processor to analyze the solution graph resulted from topology optimization before the generation of CAD models. Algorithms that derive the geometric shape from the solution graph by recognizing features as well as assigning parameters are introduced. Then, feature-based CAD models of bifurcated sheet metal products are automatically generated. The proposed methods and algorithms are implemented with Python and validated with a use-case. Benefits and limitations of the proposed methods are discussed.


Author(s):  
Thiago Weber Martins ◽  
Christian Steinmetz ◽  
Katharina Albrecht ◽  
Reiner Anderl

Within the Collaborative Research Center 666 the algorithm based product development process has been established. It is based on state of the art product development methodologies and enhanced in order to optimize the product development process of integral bifurcated sheet metal parts. Algorithms based on mathematical optimization approaches as well as the initial product requirements and constraints information are applied to obtain an optimized design as CAD-Model. Regarding this methodology there are still some challenges to be solved, such as reduction of iterations steps to elaborate final product design as CAD-model, use of heterogeneous data as well as software and enhancement of information exchange. Therefore, this paper introduces a concept for a web-based application to support the algorithmic product development methodology and CAD modeling in CRC 666. It enables the development and adaptation of integral bifurcated parts based on the initial optimization data provided by XML-files. Besides the description of use cases and use scenarios, the concept is implemented as a web-based application for validation purposes. Based on the validation, advantages and limitations of the presented approach are discussed.


Author(s):  
Thiago Weber Martins ◽  
Lars Niemczik ◽  
Reiner Anderl

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.


Author(s):  
Cong Hong Phong Nguyen ◽  
Young Choi

The lightweight representation of three-dimensional computer-aided design (3D CAD) models has drawn much attention from researchers as its usefulness in collaborative product development is vast. Existing approaches are mostly based on feature depression or mesh-based simplification. In this article, a new approach for 3D CAD lightweight representation based on combining triangular mesh representation and boundary representation (B-rep) is proposed. The corresponding data structure as well as the conversion method from original data given in B-rep was developed. Considered as an essential application in collaborative product development, a case study on the visualization process of large-scale assembly models represented in the proposed lightweight representation was also conducted. The validation of the approach was performed via experiments with 3D CAD models in SAT format and by benchmarking with the conventional all-faceted approach with the same level of mesh resolution.


Author(s):  
Marcus Sandberg ◽  
Tobias Larsson

Automating redesign is an approach for engineering designers to prevent design related manufacturability problems in early product development and thus reduce costly design iterations. A vast amount of work exists, with most research findings seemingly staying within the research community rather than finding its way into use in industrial settings where research issues have often evolved from the concerned applied research. The aim of this paper is to present an approach with industrial implementation potential regarding automating redesign of sheet-metal components in early product development to avoid manufacturing problems due to design flaws and non-optimal designs. Geometry, generated by a knowledge-based engineering (KBE) system, gives input to the case-based reasoning (CBR) governed manufacturing planning. If geometry is found non-manufacturable or enhancement of already manufacturable geometry is possible, the CBR system will suggest redesign actions to resolve the problem. CBR extends the capabilities of the rule-based KBE-system by enabling plan-based evaluation. The approach has the potential for industrial implementation, since KBE is often closely coupled to an industrial CAD-system, hence enabling technology is at the industry. Also, combining KBE and CBR reduces the coding effort compared to coding the whole design support with CBR, as feature recognition is simplified by means of KBE. A case study of development of sheet-metal manufactured parts at a Swedish automotive industry partner presents the method in use. As it is shown that redesign can be automated for sheet-metal parts there is a potential for reducing costly design and manufacturing iterations.


2007 ◽  
Vol 344 ◽  
pp. 251-258 ◽  
Author(s):  
Peter Groche ◽  
Jens Ringler ◽  
Dragoslav Vucic

Due to the high effort involved, bifurcated constructions in mass market products made from sheet metal remained largely unused. Extruded profiles with cross-sections containing bifurcations show the possibility to increase the stiffness and allow modern lightweight design using load optimized structures as well as in box strap, sandwich and stringer constructions or different profiles. The two new forming processes linear flow splitting and linear bend splitting developed at the PtU enable the production of bifurcated profiles in integral style made of sheet metal without joining, lamination of material or heating of the semi-finished product. These forming processes use obtuse angled splitting rolls and supporting rolls to transform the sheet metal at ambient temperature. Whereas the linear flow splitting process increase the surface of the band edge and forms the band into two flanges. At linear bend splitting a bended sheet metal as semi finished product is used. Thereby bifurcations at nearly any place of a sheet metal can be produced. Both processes induce high hydrostatic compressive stresses in the local forming zone during the process which leads to an increased formability of the material and thereby to the realization of large strains. Parts produced are characterized by increased stiffness, high surface hardness and low surface roughness. Experimental investigations have shown an increasing of the band edge surface at maximum splitting depth up to 1800%. By a following forming process new multi-chambered structures and integral stringer construction can be realized with thin walled cross-sections from steel of higher strength.


2008 ◽  
Vol 584-586 ◽  
pp. 68-73 ◽  
Author(s):  
Clemens Müller ◽  
Tilman Bohn ◽  
Enrico Bruder ◽  
Peter Groche

Linear flow splitting is a new continuous cold forming process where the edge of a sheet metal is formed into two flanges by splitting and supporting rolls. Thus the production of bifurcated profiles from sheet metal without lamination of material becomes feasible. The production of such structures takes place incrementally in a modified roll forming machine. Experimental investigateons on a HSLA steel show, that even at a surface increase of the sheet edge of about 1800% no cracks were nucleated in the profiles. EBSD measurements in the splitting centre reveal that similar to other SPD processes UFG microstructures develop in the processing zone. Thus a steady state is reached in the processing zone where increasing strain has no more (or little) influence on the materials properties i.e. its deformability, as it is typical for SPD-processes. The formation of UFG microstructures is considered to be a mandatory condition for the linear flow splitting process, as it improves the formability of the material to the extremely high level required for this process. The mechanical properties of profiles produced by linear flow splitting are characterised by large gradients, depending on the local deformation and the resulting microstructure. Very high hardness is measured at the former processing zone, i.e. the splitting centre and the flange surface, where severe plastic deformation takes place and UFG microstructures are present. In direction to lower deformation i.e. with increasing distance to the splitting ground or flange surface the hardness decreases close to the level of the undeformed material. In the present paper the linear flow splitting process is introduced and the microstructural development in the process zone is discussed on the base of EBSD measurements on profiles of the steel ZStE 500. The repartition of mechanical properties in a bifurcated profile is demonstrated by detailed hardness measurements.


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