Enhanced Semi-Analytical Process Simulation of Air Bending

Abstract

The air bending process is one of the most widely used process for the manufacturing of sheet metal bending parts made of thin as well as of thick sheet metal. Although the air bending process offers a very high production potential due to its great flexibility, it is associated with certain problems which can negatively influence the shape and dimensional accuracy of the bending parts. Examples for such negative influences are the springback of the material, the batch variations, or the deflections of the bending machine and tools. These differences have to be considered either in the determination of the process parameters or they have to be compensated later on in the manufacturing process itself. A well established approach to calculate process data for forming processes is the use of a process simulation. At the Institute of Forming Technology and Lightweight Construction (IUL) a simulation software called Sheet Metal Bending Simulation (SMBS) has been developed and successfully been tested for the field of sheet metal bending, based on semi-analytical approaches. Although it already provides very satisfactory results in general, disturbances such as material and batch variations as well as the deflections of C-frame, machine table, and press brake ram can still negatively affect the prediction of the punch displacement necessary to achieve a certain bend angle. While material and batch variations cannot properly be considered in a process simulation at present, the afore mentioned influences offer a promising potential for improvements. Therefore, in order to further improve the accuracy of predicted quantities such as punch displacement and bending angle, a new module describing the elastic machine behaviour of press brakes has been developed and successfully been integrated in the process simulation SMBS. Experimental investigations have been carried out on a conventional CNC press brake to verify the efficiency of the newly implemented approach.

Concept for a Self-correcting Sheet Metal Bending Operation

“…A number of modeling methods for metal bending processes have been developed. Heller et al, for example, developed a mathematical model for a fast semi-analytical simulation of the air bending process of thin as well as of thick sheets [4] and Ridane enhanced this approach by regarding the elastic machine behavior [5]. To investigate and consider the spring back Panthi set up a total-elastic-incremental-plastic algorithm, for large deformation and large rotational problems [6].…”

Analysis of High Speed Bending Operations as Basis for Integrating Self-correcting Components to Increase Process Reliability

“…The parameters for the correction algorithm can be defined using a bending process model such as a multi-body simulation model. A number of modeling methods for metal bending processes are detailed in (Ridane et al, 2005;Schilling, 1993;Heller et al, 2006;Panthi et al, 2010), but a multi-body simulation model has major advantages for designing and testing a control strategy for corrective action in the process models (Brecher et.al., 2013;Damerow et al, 2012;Borzykh et al, 2012). Once the parameters have been defined, the correction algorithm can be tested and optimized under real conditions on a test facility.…”

Model-Based Approach for Self-correcting Strategy Design for Manufacturing of Small Metal Parts

“…Multi Body System (MBS)-model of the bending process was built up for analysis and design of the control strategy. There are a number of models for the simulation detailed in various literatures[Ridane, N. (2005),Schilling, R. (1993),Heller, B. (2002)], but in our case an MBS model was chosen that consists of the workpiece, the tool, and the punch-bending machine[Wittenburg, J.…”