توسعه یک مدل شبیه سازی سه بعدی تحلیلی از روند تسطیح

Sheet metal often shows shape defects, which is not complying with the increasing requirements for the quality of the products needed to satisfy the highest demands on finer tolerances. Due to the market's high requirements on the quality of products, new high-technology levelling machines were developed. The adjustment of these levellers is very complicated and a successful adjustment depends mainly on the experience of the line operator. As the computational power has developed over the past years, simulation becomes more important in the production process and is used in analysing the effects of leveller adjustments on the unflattened sheet metal. In this study, edge- and centre waves are investigated. In order to find a suitable adjustment of the leveller to reach a flat sheet metal, an analytical 3D simulation model has been developed using the Matlab programming environment. The sheet metal will be firstly analyzed and visualized before and after deformation. A user-friendly interface has been developed to enter the required parameters before starting the simulation. Different methods have been used to investigate the effect of the levelling process on the sheet metal and to calculate the remaining shape defects after levelling. The simulation results were validated by experiments and are represented in this paper.

Sheet metal often shows shape defects, which is not complying with the increasing requirements for the quality of products needing to satisfy high demands on tolerances. As the computational power has increased over the past years, simulation is playing an outstanding role in the production process and is becoming much more effective. Simulation proved to be a powerful tool for defining and developing new methods. Sheet metal defects can be distinguished into two main types: surface-to-surface and edge-to-edge length differential shape defects. Guericke has found that the first one can be eliminated using conventional roller levellers Guericke et al. (1983), while Buchholz and Henrich said that the eliminating of edge-to-edge length differential problems requires levellers featuring an adjustable bending of the levelling rolls (Buchholz 1973; Henrich, 1994) (see Fig. 1). By means of this, the centre and the left or right edge zones of the sheet stripe can be stretched to a different extent. Bräutigam stated that a successful adjustment of these machines is complex and depends mainly on the experience of the line operator (Bräutigam, 2009 and Guericke, 1994).

The intent of the presented work is the development of an analytic simulation model of a levelling machine for sheet metal to eliminate edge and middle waves. The model allows for a virtual determination of suitable settings for levellers featuring adjustable bending of the levelling rolls. By this, waves at the edges as well as in the middle of the sheet metal can be eliminated. An adequate approach for the calculation and a graphical user interface was developed and realized using the programming environment MATLAB. A description of modern levellers, the acquisition of the sheet metal topography and the method for the virtual determination of shape defects are presented. Experimental and virtual levelling tests were carried out and the approach was validated for different shape defects. The parametric structure of the model allows a quick individual configuration of different machines and sheet metal properties. The results of Simulated and experimental levelling process agree in a wide range with divergences in an expected range.