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Article
Surface matrix based Machining Planes Determination for Milling Process (Roughing Stage)
ايجاد مستويات التشغيل بالأعتماد على مصفوفة السطح لعملية التفريز [ مرحلة التشغيل الأولي

Author: Laith A. Mohammed
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2007 Volume: 25 Issue: 2 Pages: 153-167
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

This paper deals with machining plane determination process for CNC millingmachining. Three methods, Matrix, 3D contour matrix and flow line arepresented. All methods depend on the data set point of the surface matrix ofthe workpiece to be machined. All methods can be used to automate theCAD/CAM operation for roughing process in milling machining. Two surfaceexamples are included to illustrate all methods. By a comparison among thethree presented methods, a conclusion has been reached that the presented 3Dcontour matrix method requires maximum number of blocks to build G-codesprogram for CNC tool path programming. It means that, this method requireslonger time to accomplish tool paths. On the other hand the other twomethods require minimum number of blocks of G-codes and shorter time forroughing.

تتناول هذه المقالة عملية ايجاد مستويات التشغيل لعملية التفريز باستخدام مكائن القطعالمبرمجة. تم تقديم ثلاث اساليب لهذا الغرض وهي اسلوب المصفوفة واسلوب مصفوفة الحدودثلاثية الأبعاد واسلوب المسار الأنسيابي. جميع هذه الأساليب تعتمد على التعريف البياني لنقاطسطح الجزء المطلوب تشغيله. يمكن استخدام هذه الأساليب لأتمتة عملية التشغيل بالتفريز (فيمرحلة التشغيل الأولي). تم تطبيق هذه الأساليب على نموذجين من السطوح الهندسية. منخلال المقارنة بين الطرق التي تم تناولها، تم التوصل الى استنتاج ان اسلوب مصفوفة الحدودثلاثية الأبعاد تتطلب أكبر عدد من الصفوف البرمجية لأعداد برنامج الحركة لمكائن القطعالمبرمجة. أي ان هذا الأسلوب يحتاج زمن أطول لتحقيق مسارات القطع . بينما الأسلوبينالأخرين فانهما يتطلبان عدد أقل من الصفوف البرمجية ووقت أقصر لأجراء عملية التشغيلالأولي.


Article
An Approach To 3D Surface Curvature Analysis
التحليل ثلاثي الأبعاد لتقوس السطح

Authors: Ghasan A. Al-Kindi --- Laith A. Mohammed
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2005 Volume: 24 Issue: 7 Pages: 844-852
Publisher: University of Technology الجامعة التكنولوجية

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Abstract


Article
Statistical and Visual Analysis of Error In Interpolating Sculptured Surfaces

Authors: Tahseen F. Abbas --- Aqeel S. Baden --- Muhamed A. Salih
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2011 Volume: 29 Issue: 12 Pages: 2520-2538
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

This paper presents a general method for automatic surface interpolation fromrange data and describes the implementation of high order 2D langrangian methodsfor interpolating surfaces from 3rd to 8th order. It uses a modified 2D lagrangianmethod to interpolating, reconstructing and modeling several surfaces, and due to thisinterpolation there will be an error between interpolated surface and the original one,this paper present an algorithm to detect, represent and analyze these interpolatingerrors and statistical criteria to compare the error in representing the sculpturedsurfaces that interpolated with different order basis functions. The comparison isperformed using a mathematically defined data as real data obtained from theproposed models.The system has been implemented for the design of several sculptured surfaces toillustrate the system flexibility. Then the design results have been implemented formanufacturing two of these surfaces using three axis vertical CNC milling machinetool with ball end mill cutter. The method can be used in a variety of CAD/CAMapplications and it has proven to be effective as demonstrated by a number ofexamples using real data from mathematical functions. By applying the proposedsurface interpolating models the percent error was found to be ranged between0.00001% for some model to 3.5% for some other interpolated models with Lagrangemethod.


Article
A UNIFIED METHOD FOR B-SPLINE’S SURFACE MODELING (INNOVATIVE METHOD FOR DATA TRANSFORMATION FROM CAD TO CAM PROGRAMS)
طريقة موحدة لنمذجة السطوح( طريقة مبتكرة لنقل المعلومات من برنامج التصميم ))CAD)الى برنامج التصنيع (CAM)

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Abstract

In present work, a unified method for geometric transfer from CAD to CAM program has been investigated using iterative process. The B-spline objects (curves and surfaces) of 3rd degree one patch matrix had been derived and formulated using MATLAB program to construct a computer program for the geometric transfer as a case study. The procedure of converting the sculpture surfaces from CAD program to CAM program without any geometrical distortion had been presented. The implementation of transfer data and the simulation using UGS program during transformation of any complex profile shape from CAD to CAM program is done without any distortion in final profile in CAM program. It was found that the results obtained by applying the present method which utilizes a less time as compared with the other methods are in a good agreement with the experimental results.

في العمل الحالي تم أجراء طريقة هندسية للنقل من برنامج CAD إلىCAM باستخدام طريقة معدلة .تم اشتقاق وصياغة مصفوفة لرقعة واحدة من الدرجة الثالثة لأجسامB-spline (المنحنيات والأسطح) باستخدام برنامج MATLAB لإنشاء برنامج حاسوبي لنقل البيانات الهندسية كدراسة للحالة. تم تمثيل إجراءات تحويل الأسطح النحتية من برنامج CAD إلى برنامج CAMبدون أي تشوه هندسي .تم تنفيذ نقل البيانات والمحاكاة باستخدام برنامجUGS أثناء تحويل لأي شكل معقد من برنامج CAD إلىCAM بدون أي تشوه في الشكل النهائي في برنامجCAM . وجد ان النتائج التي تم الحصول عليها مطابقة مع النتائج العملية بتطبيق الطريقة الحالية والتي تستغرق وقت اقل مقارنة مع الطرق الاخرى .


Article
Development of Algorithms to Represent Intermediate Layers for Machining Sculptured Surfaces

Authors: Tahseen A. Jawad --- Tahseen F. Abbas
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2011 Volume: 29 Issue: 11 Pages: 2244-2258
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

The objective aim of this research is to develop an algorithm for design and manufacture sculptured surfaces that are common in a wide variety of products such as dies, automobile, and aircrafts components. In the design stage Bezier technique has been used to represent the desire surface. In rough-machining stage, the number of intermediate layers depend on the geometry of the desired surface and on themaximum allowable depth of cut, an algorithm has been proposed to represent these layers, whereas another efficient algorithm has been proposed to represent the semifinished layer depends on the tangents and normal vectors along all the points of the desired surface to create the offset surface. The desired surface generated points usingBezier technique are used as cutter location points for the finish machining tool path. Flat end mill (φ 12mm) has been used for the intermediate stages machining (roughing), while (φ 12mm) ball end mill have been used for both semi-finish and finish machining. The developed algorithm have been tested by several designed sculptured surfaces, its proved good flexibility and efficiently in all of its stages, theresults have been implemented for machining one of these surfaces [fifteen intermediate layers, semi-finished layer, and finished] using 3-axis vertical CNC machine. The proposed rough machining algorithm reduces the machining time as compared with contour tool path by 15% for case study two and reduces the NC file size 52% for case study three.

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