Papers by Author: H.M.A. Hussein

Abstract: The aim of this work is to develop an integrated system for facilitating the process of designing the drawing dies and their component. The developed system is based on the integration between Computer Aided Process Planning in Sheet Metal Drawn parts “CAPP”, and the Computer Aided Design in Deep Drawing Die components “CAD”. Both modules are coded using Visual Basic program and joined with AutoCAD. The CAPP module made to report the drawing load and to plot the shape of the drawn shell in each stage of the Axis-Symmetric Deep Drawing process. Based on the reported shell geometry, the dimensions of the die components are calculated and transferred to the CAD module. The CAD module, which is based on many data bases (standard parts, sheet metal data), plots the required deep drawing die components for each drawn stage on the AutoCAD monitor. A demonstrated example is presented to validate the developed system and to show that the system results are acceptable.

Abstract: To eliminate geometric deviations of sheet metal subjected to an air-bending process from the geometry required by the designer, it is necessary to predict the accurate value of the springback. Springback is the elastic deformation observed upon removal of the load during a bending process. In order to predict the springback amount, a multidimensional function should be approximated. In this paper, a neural network metamodel (NNM) based on the back propagation algorithm is introduced to predict the springback value. A verified nonlinear finite element model is developed to generate NNM training data. To select the training data for the NNM, computer generated D-optimal designs are utilized. The NNM developed model in this research can be used in determination of the springback value in sheet metal bending.

Abstract: Two-dimensional curves are represented by a list of vertices and other parameters that control the shape or curvature of the segments. In computer programming to deal with closed two-dimensional curves, it is often required to know the direction of the curve, which is reflected by the sequence of the vertex data. It can be anticlockwise or clockwise. This paper presents a robust, linear algorithm to determine the direction of a closed two-dimensional curve, by computing the total angular change of a tangent vector travelling along the curve for a complete cycle. A new, robust linear algorithm is proposed for the determination of the positional relationship of a point to a two-dimensional curve. For curves that consist of line and arc segments, which are most commonly used in engineering applications in computer aided design, the paper presents algorithms and procedures for solving the above problems.

Abstract: Die-set is an essential tool accessory in sheet metal punching and blanking. The selection of the die-set represents an important activity in the die design operation. Time and money consumed in this operation could be saved by using an automated selection system for die-set components. This paper discusses an intelligent die-set selection system using the AutoCAD platform. The developed system is able to work as either standalone or connected with any die design CAD system by using the well-known AutoCAD programming tools. The proposed system is built using IF-THEN rules approach. The system code is developed using AutoCAD with Visual Basic. A data-base of Nasr Automotive Company (NASCO) for die-set was considered, from which suitable size of die-set was selected automatically. The proposed system could reduce the consumed time in the tool room department from hours to minutes and could reduce effort and cost as well.

Abstract: This paper describes computer aided process planning for a freeform surface; sheet metal features. Automotive body panels are always manufactured using thin forming sheets; the developed CAPP system consists of two modules which are feature recognition module based on STEP AP203 and a process plan module; two additional modules for automotive panel CAPP system and cost estimation module are also incorporated in the system of punch and bending operation. Stamped or punched features in generative shape design are used to design automotive panels; the generative CAPP system is written in visual basic 2008 language and implemented in several case studies demonstrated in the present work. Feature recognition of punched; stamped internal features in free form surface recognized in base of data exchange files using STEP AP203 ISO-10303-21.