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دراسة مقارنة بين T - spline وNURBS في النمذجة والتشغيل باستخدام ماكنة التفريز المبرمجة == Comparison Study of T - Spline And NURBS In Modeling And Machining Using CNC Milling Machine
Author name:
مهند مصدق جعفر
Supervisor name:
ليث عبد الله محمد
General topic:
Production engineering metallurgy and materials
Specific topic:
Production Engineering
Degree:
Master
University:
University of Technology
Language:
English
University location:
Baghdad
First pages:
50T169 - p.pdf
Abstract:
نمذجة السطوح باستخدام تقنية الـ (T - spline ) تعد من اهم الوسائل المتسخدمة الان في التصميم المعان بالحاسوب (CAD).يهدف البحث الى زيادة الانتاجية من المنتجات المعقدة من خلال تعزيز عملية النمذجة السطحية للمنتج وتعزيز التصنيع باستخدام T - SPLINE للنمذجة السط | Surface modeling utilizing T - spline technique is one of the most important tool now in computer aided design (CAD).ThisThesisaims to increase the productivity of complicated products through enhancing the process of product surface modeling and manufacturing by using T - spline for surface modeling. This method provides the designer with many powerful tools to add details only where necessary on the CAD modeling, create non - rectangular topology of the surface, easily edit complex freeform models, and besides maintaining NURBS (non - uniform rational B - splines) compatibility of the model.ThisThesisuses T - spline for surface modeling and compare it with NURBS modeling to get the best modeling points between the two methods. The comparison will be through surface analysis and manufacturing process.ThisThesisincludes design of two types of models : convex model (bicycle seat) and concave model (longitudinal section of the bottle) for each T - spline surface and NURBS surface using Rhinoceros 5.0 software which has been transformed to UG - NX8.5 software to get the machining process simulation and G - code programs for the models. The models have been machined using 3 - axis vertical CNC machine (C - tek) type.Finally, analysis of surfaces (Environment Map analysis, Zebra analysis, Naked Edges analysis, Gaussian Curvature analysis, data structure analysis, Draft Angle analysis) by Rhinoceros 5.0 software and measurement of the roughness by Pocket Surf equipment and measurement runtime for machining by timer, shows that the T - Splines surfaces typically have (50 - 70%) less geometric data structure [ surfaces , 3d curve , 2d curves , vertices , edges , trims , loops , faces ] than the equivalent NURBS surface, inEnvironment Map analysis, the image of T - Spline surface for the models is reflected moreclearly than a NURBS surface, in Naked Edges analysis, the T - Spline surface for the models has a number of naked edge less than the NURBS surface, in measurement runtime for machining (roughing and finishing), the T - spline surface for the bicycle seat model is machined in (16 minutes) less than machining the NURBS surface, and the T - Spline surface for the longitudinal section of the bottle model is machined in (10 minutes) less than machining the NURBS surface. In measurement of roughness, the T - Spline surface for the bicycle seat model has (2.4861 µm) average (Ra) for patches measured roughness average (Ra), and the NURBS surface has (4.9216 µm) average (Ra) for patches measured roughness average (Ra).
