Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : CAD


Geometric Modeling of Compound NURBS Surfaces

Ali K. Alwan; Wisam K. Hamdan

Engineering and Technology Journal, 2020, Volume 38, Issue 2, Pages 277-287
DOI: 10.30684/etj.2021.168196

The design of sculptured surfaces occupies an essential area in the field of modern industrial, aerospace, and medical applications. The challenge is to design products that have complex features efficiently with great flexibility of editing in certain regions without affecting other regions, which the designer has no intent to modify. In this paper, we propose a surface design method based on compound NURBS surface to model automotive parts with 400 control points. First, a Non-Uniform B-Spline basis function is derived with a cubic degree and 20 control points. This method is utilized to design car posterior door, car hood, and rear car door as case studies.

Iterative Method of Data Transfer from CAD to CAM Systems for the Profile of Stamping Dies

Ali Abbar Khleif; Ahmed A. A. Duroobi; Ali Mohammed

Engineering and Technology Journal, 2014, Volume 32, Issue 11, Pages 2714-2721

A proposal method for data transfer from CAD to CAM program has been investigated in the present work using iterative process for the stamping dies. The Bezier and B-spline equations forcurves and surfaces of n-degree had been derived as a matrix and formulated using MATLAB program, then a computer program had been constructed for the data transfer as a case study. The procedure of converting the profile of stamping dies from CAD program to CAM program without any geometrical distortion had been presented. The implementation of data transfer and the simulation using UGS(UniGraghics Solutions) program observed that the transformation of any complex profile shape from CAD to CAM program done without any distortion in final shape of the profile in CAM program. The present method matched the experimental result conformity and used in short time as compared with other methods.

Sequencing the Randomly 2D Drawing Entities Using DXF Format

Baraa M.H. Albaghdadi

Engineering and Technology Journal, 2013, Volume 31, Issue 8, Pages 1567-1579

The exchange of the data between the drawing programs like this one used in this research, AutoCAD, and the other application programs is very important to develop the applications in CAD systems. The present paper aims to make a logic sequence for the entities that are drawn randomly to prepare them to further CAD or CAM manipulations. The methodology in this work is using the DXF (Data Exchange File) which represents a CAD file format in which the drawing is saved by using AutoCAD package. All the required manipulations, begging from extraction the data of the drawing entities to accomplishment the sequencing, have been done by building a suitable visual basic program. Also, the AutoCAD package has been used as a checking tool for the results after applying the proposed program, by opening the new DXF file format to AutoCAD environment. The results show that the use of the concept of exchanging the data in CAD environment is a good way to apply the methodology of the research.

Automatic Features Recognition for Symmetrical Shapes

Amjad Barzan Abdulghafour; Mithal Ahmed Al-Bassam

Engineering and Technology Journal, 2012, Volume 30, Issue 12, Pages 2027-2043

The future of computer-aided design (CAD) and computer-aided manufacturing
(CAM) depends on the ability of their two processes to communicate with each
other and with intermediate manufacturing database. Therefore, the development of
a successful approach to the integration of CAD and CAM will require solution to
several fundamental problems in planning and geometric reasoning. The first
problem is the interface between CAD and CAM, that automatic feature
recognition is an indispensable technique to solve this problem. We address this
problem by developing an algorithm, which is considered an effective approach to
extraction and of hybrid manufacturing features of symmetrical parts. The
developed algorithm is based on the syntactic pattern primitive concept supported
by production rule technique. This approach is considered a powerful tool applied
to feature recognition field for symmetrical parts.

Development Approach of Automated Recognition for Isolated and Intersection (Complex) Manufacturing Features for Prismatic Mechanical Parts

Hussein. S. Ketan

Engineering and Technology Journal, 2010, Volume 28, Issue 21, Pages 6215-6227

The intersection between part features caused ambiguousness in feature
representation because the topology in this case will be change. To overcome this no unique and ambiguousness by combine the topology and characteristics to extract and recognize the intersection features. This paper introduces new general algorithm to: (1) construct developed Attributes Adjacency Matrix (DAAM) and (2) analysis the DAAM to extract and recognize the isolated and intersection (complex) manufacturing features. This algorithm consists of two stages, preprocessor
stage which performs extraction of information from Design Exchange
Format (DXF) file, and post-processor stage which recognizes part’s features depending on the relations included in DAAM. The parts are represented in AutoCAD using Constructive Solid Geometry (CSG) technique and the algorithm built in visual basic. Several parts tested and succeed to recognize several types of intersection (complex) manufacturing features. The main contributions of this research include building the adjacent relations between faces of the part by
geometrical characteristics in form of matrix, and use clustering operation to extract the exact faces of feature and use different classes of geometrical characteristics to assisting to recognize interacting depression prismatic features.

An Investigation of Object Shadows Utilization In 3D Shape Re-Construction Using Inexpensive Equipment

Ghassan A. Al-Kindi; Ali Abbar Khleif

Engineering and Technology Journal, 2010, Volume 28, Issue 4, Pages 836-852

An approach for automatic 3D object re-construction using its shadow is
presented. The approach investigates the use of information inherited by the
generated object shadows to re-construct the object geometry. An algorithm is
developed that make use of object height information for the directions associated
with the incident light and the generated object shadows, hence, acquired height
features represents the object features that have actually obstructed the incident
light. The technique is tested using objects of different shapes. Close to real
measurements are gained and the overall accuracy of the system is found to be
within 0.75 mm using the adopted imaging hardware and setup. Obtained results
confirmed the validity of the proposed approach.

Studying Curve Interpolator for CNC System

Maan Aabid Tawfiq; Laith A. Mohammed; Abbas M. Jabber Al-Fnzi

Engineering and Technology Journal, 2009, Volume 27, Issue 11, Pages 2205-2222

This thesis focuses on developing algorithm to calculate best length line
segments in (u) and (w) directions. By of tool paths for free form surfaces based
on the required accuracy of the manufactured part, which is represented by
mathematical curves and surfaces. Bezier method was used to apply the proposed
algorithms. The proposed algorithms consist of two parts; the first part is to
calculate the better length line segment in (u) direction between cutter contact
points (CC), the second part is to calculate the better line segment in (w) direction
depending on the type of surface, cutter radius, tolerance and height scallop being
given. The algorithms are applied in production field such as design of extrusion
dies using three types of curve interpolation such as approximation cubic Bezier,
interpolator Bezier and compound-CRHS profile die. In this paper, the
manufactured parts are machined using a 3-axis CNC milling machine. The
machining operations are simulated using SURFCAM software depending on the
different interpolation techniques mentioned. An evaluation test is applied to the
three interpolation methods based on Finite Element Method (FEM) using
ANSYS 9.0 software to expect the strain and force required to extrude billet
through the dies which are designed using the three mentioned interpolation
methods. The G-code programs have been implemented on 5-axis CNC machine
(Okuma VH-40-HS dynamic machine), the sample material is (cibatool) and the
machining process is achieved without a lubricant at the Protoshop Oy in
Helsinki/Finland.

Attribute Adjacency Matrix Approach for Extracting and Recognizing Manufacturing Prismatic Features from CAD Models

Omar H. Hussoon; Hussein S. Ketan

Engineering and Technology Journal, 2009, Volume 27, Issue 10, Pages 2085-2099

This paper introduces Developed Attributes Adjacency Matrix (DAAM)
approach for extracting and recognizing of part’s features, by deal with decoupling
or isolated manufacturing features. The proposed algorithm consists of two stages,
pre-processor stage which perform extraction of information from Design
Exchange Format (DXF) file format in Computer Aided Design (CAD), and postprocessor
stage which recognizes part’s features depending on attributes
adjacency matrix.
The main contributions of this research include building the adjacent relations
between faces of the part by geometrical characteristics in form of matrix, and use
clustering operation to extract the exact faces of feature and use different classes
of geometrical characteristics to assisting to recognize depression prismatic
features useful in machining and other application such as dimensional inspection
and assembly.

Design of Free – Form Planar Closed Curves Using Four Point Interpolation

Wissam K.H; Hussam L. Alwan; Bushra B. Abd Alhassan

Engineering and Technology Journal, 2008, Volume 26, Issue 8, Pages 976-985

It is desirable to construct a free-form closed curve, since large numbers of
mechanical elements follow these curves. In this work we present a parametric
interpolation for construction a free form closed curves using four point interpolation
technique. The problems and solutions approach for closing open or disjoint curves is
demonstrated taking C1 continuity as a criterion for the solution of these problems.
When the coordinates of any number of control points are introduced, the proposed
algorithm constructs and closed the intended curve. The designer is free to vary and
manipulate these control points to change the shape of the desired curve.