Lars Thyssen

On the increase of geometric accuracy with the help of stiffening elements for robot-based incremental sheet metal forming

This paper describes new developments in an incremental, robot-based sheet metal forming process (‘Roboforming’) for the production of sheet metal components for small lot sizes and prototypes. The incremental sheet forming (ISF) offers high geometrical form flexibility without the need of any part-dependent tools. To transfer the ISF to industrial applications, it is necessary to respond to the still existing constraints, e.g. the low geometrical accuracy. Especially the subsequent deformation resulting from the interaction of differently shaped elements causes geometrical deviations, which are limiting the scope of formable parts. The impact of the resulting forming forces will vary according to the shape of the individual elements. For this, the paper proposes and examines a new approach to stabilize the geometrical accuracy without losing the universal approach of Roboforming by inserting stiffening elements. Those elements with varying cross-sections at the initial area of various orientations must b...

Influence of part orientation on the geometric accuracy in robot-based incremental sheet metal forming

This article describes new developments in an incremental, robot-based sheet metal forming process (‘Roboforming’) for the production of sheet metal components for small lot sizes and prototypes. The dieless kinematic-based generation of the shape is implemented by means of two industrial robots, which are interconnected to a cooperating robot system. Compared to other incremental sheet metal forming (ISF) machines, this system offers high geometrical form flexibility without the need of any part-dependent tools. The industrial application of ISF is still limited by certain constraints, e.g. the low geometrical accuracy. Responding to these constraints, the authors present the influence of the part orientation and the forming sequence on the geometric accuracy. Their influence is illustrated with the help of various experimental results shown and interpreted within this article.

Robot-based additive manufacturing for flexible die-modelling in incremental sheet forming

The paper describes the application concept of additive manufactured dies to support the robot-based incremental sheet metal forming process (‘Roboforming’) for the production of sheet metal components in small batch sizes. Compared to the dieless kinematic-based generation of a shape by means of two cooperating industrial robots, the supporting robot models a die on the back of the metal sheet by using the robot-based fused layer manufacturing process (FLM). This tool chain is software-defined and preserves the high geometrical form flexibility of Roboforming while flexibly generating support structures adapted to the final part’s geometry. Test series serve to confirm the feasibility of the concept by investigating the process challenges of the adhesion to the sheet surface and the general stability as well as the influence on the geometric accuracy compared to the well-known forming strategies.The paper describes the application concept of additive manufactured dies to support the robot-based incremental sheet metal forming process (‘Roboforming’) for the production of sheet metal components in small batch sizes. Compared to the dieless kinematic-based generation of a shape by means of two cooperating industrial robots, the supporting robot models a die on the back of the metal sheet by using the robot-based fused layer manufacturing process (FLM). This tool chain is software-defined and preserves the high geometrical form flexibility of Roboforming while flexibly generating support structures adapted to the final part’s geometry. Test series serve to confirm the feasibility of the concept by investigating the process challenges of the adhesion to the sheet surface and the general stability as well as the influence on the geometric accuracy compared to the well-known forming strategies.

Adaptive scallop height tool path generation for robot-based incremental sheet metal forming

Incremental sheet metal forming is an emerging process for the production of individualized products or prototypes in low batch sizes and with short times to market. In these processes, the desired shape is produced by the incremental inward motion of the workpiece-independent forming tool in depth direction and its movement along the contour in lateral direction. Based on this shape production, the tool path generation is a key factor on e.g. the resulting geometric accuracy, the resulting surface quality, and the working time. This paper presents an innovative tool path generation based on a commercial milling CAM package considering the surface quality and working time. This approach offers the ability to define a specific scallop height as an indicator of the surface quality for specific faces of a component. Moreover, it decreases the required working time for the production of the entire component compared to the use of a commercial software package without this adaptive approach. Different forming ...