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UNIGRAPHICS-NX3 FOR

By Parthiban Delli

Ming Leu

Department of Mechanical and Aerospace Engineering

University of Missouri – Rolla Rolla, Missouri 65401

This project is funded by the National Science Foundation

Advanced Technological Education Program and Partners of the Advancement of Collaborative Engineering Education

FOREWORD6
CHAPTER 1 - INTRODUCTION7
1.1 PRODUCT REALIZATION PROCESS7
1.2 BRIEF HISTORY OF CAD/CAM DEVELOPMENT8
1.3 DEFINITION OF CAD/CAM/CAE10
1.3.1 Computer Aided Design – CAD10
1.3.2 Computer Aided Manufacturing – CAM10
1.3.3 Computer Aided Engineering – CAE10
1.4 SCOPE OF THIS TUTORIAL1
CHAPTER 2 - GETTING STARTED IN UNIGRAPHICS13
2.1 OPENING UNIGRAPHICS AND FILES13
2.1.1 Open Unigraphics13
2.1.2 Open a New File14
2.1.3 Open a Part File15
2.2 PRINTING, SAVING AND CLOSING PART FILES16
2.2.1 Print a Unigraphics Image16
2.2.2 Save Part Files17
2.2.3 Close Part Files17
2.2.4 Exit an Unigraphics Session18
2.2.5 Simultaneously Saving All Parts and Exiting18
2.3 UNIGRAPHICS-NX3 INTERFACE:18
2.3.1 Mouse Functionality19
2.3.2 Unigraphics Gateway21
2.3.3 Geometry Selection24
2.3.4 User Preferences27
2.4 COORDINATE SYSTEMS30
2.4.1 Absolute Coordinate System30
2.4.2 Work Coordinate System30
2.4.3 Existing Coordinate Systems30
2.4.4 Move the WCS30
2.5 USING LAYERS31
2.5.1 Layer Control31
2.5.2 Commands in Layers32
2.6 IMPORTANT COMMANDS/DIALOGS36
2.6.1 Toolbars36
2.6.2 Transform Functions37
CHAPTER 3 - FORM FEATURES39
3.1 OVERVIEW39
3.2 TYPES OF FEATURES39
3.3 PRIMITIVES43

INDEX 3.3.1 Model a Block ....................................................................................................... 43

3.4 REFERENCE FEATURES48
3.4.1 Datum Plane48
3.4.2 Datum Axis50
3.5 SWEPT FEATURES51
3.5.1 Extruded Body51
3.6 REMOVE FEATURES54
3.7 EXERCISE - MODEL A WASHER57
CHAPTER 4 – FEATURE OPERATIONS58
4.1 OVERVIEW58
4.2 TYPES OF FEATURE OPERATIONS58
4.3 FEATURE OPERATIONS ON MODELS63
4.3.1 Model a Hexagonal Screw63
4.3.2 Model an L-Bar68
4.3.3 Model a Hexagonal Nut75
4.3.4 Model a Rack with Instances78
4.4 EXERCISE - MODEL A CIRCULAR BASE83
CHAPTER 5 – DRAFTING84
5.1 OVERVIEW84
5.2 DRAFTING OF MODELS85
5.2.1 Drafting85
5.2.2 Dimensioning90
5.2.3 Sectional View95
5.2.4 Drafting and Dimensioning of an Impeller hexagonal bolt96
5.3 EXERCISE - DRAFTING AND DIMENSIONING OF A CIRCULAR BASE100
CHAPTER 6 – SKETCHING101
6.1 OVERVIEW101
6.2 SKETCHING FOR CREATING MODELS102
6.2.1 Model an Arbor press Base103
6.2.2 Model an Impeller Lower Casing115
6.2.3 Model an Impeller123
6.3 EXERCISES127
CHAPTER 7 – FREEFORM FEATURE130
7.1 OVERVIEW130
7.1.1 Creating Freeform Features from Points130
7.1.2 Creating Freeform Features from Section Strings131
7.1.3 Creating Freeform Features from Faces133
7.2 FREEFORM FEATURE MODELING133
7.2.1 Modeling with points133
7.2.2 Modeling with a point cloud137
7.2.3 Modeling with curves139
7.2.4 Modeling with curves and faces142
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3.3.2 Model a Shaft ........................................................................................................ 45 7.3 EXERCISE - MODEL A MOUSE.............................................................................145

8.1 OVERVIEW146
8.2 TERMINOLOGIES146
8.3 ASSEMBLY MODELS147
8.3.1 Top-Down Modeling147
8.3.2 Bottom-Up Modeling148
8.3.3 Mixing and Matching148
8.4 MATING CONDITIONS148
8.5 IMPELLER ASSEMBLY150
8.6 EXPLODED VIEW OF IMPELLER ASSEMBLY164
8.7 EXERCISE - ARBOR PRESS ASSEMBLY169
CHAPTER 9- MANUFACTURING170
9.1 GETTING STARTED WITH MANUFACTURING MODULE170
9.1.1 Creation of Blank170
9.1.2 Setting Machining Environment172
9.1.3 Operation Navigator173
9.1.4 Machine Coordinate System (MCS)174
9.1.5 Geometry Definition174
9.2 CREATING OPERATION AND PARAMETER SETTING176
9.2.1 Creating a new Operation176
9.2.3 Tool Creation and Selection177
9.2.4 Cut Method180
9.2.4 Step Over and Scallop Height:181
9.2.5 Depth per cut182
9.2.6 Cutting Parameters183
9.2.7 Avoidance185
9.2.8 Feedrates186
9.3 PROGRAM GENERATION AND VERIFICATION188
9.3.1 Generating Program188
9.3.2 Tool Path Display189
9.3.3 Tool Path Simulation189
9.3.4 Gouge Check193
9.4 OPERATION METHODS193
9.4.1 Roughing193
9.4.2 Semi-Finishing194
9.4.3 Finishing Profile197
9.4.4 Finishing Contour Surface205
9.4.5 Flooring210
9.5 POST PROCESSING213
9.5.1 Creating CLSF214
9.5.2 Postprocessing216
CHAPTER 10- FINITE ELEMENT ANALYSIS218
10.1 INTRODUCTION TO FEA218
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10.1.3 Scenario Navigator2
10.1 SCENARIO CREATION2
10.2.1 Material Properties224
10.2.2 Loads224
10.2.3 Boundary Conditions225
10.2.4 Meshing226
10.3 SOLVING AND RESULT SIMULATION228
10.3.1 Solving the Scenario228
10.3.2 FEA Result229
10.3.2 Simulation231
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10.1.2 Structure Module ............................................................................................... 220 10.4 EXERCISE-ARBORPRESS L-BAR........................................................................ 234

Unigraphics is one of the world’s most advanced and tightly integrated CAD/CAM/CAE product development solutions. Spanning the entire range of product development, Unigraphics delivers immense value to enterprises of all sizes. It simplifies complex product designs, thus speeding up the process of introducing products to the market.

The Unigraphics software integrates knowledge-based principles, industrial design, geometric modeling, advanced analysis, graphic simulation, and concurrent engineering. The software has powerful hybrid modeling capabilities by integrating constraint-based feature modeling and explicit geometric modeling. In addition to modeling standard geometry parts, it allows the user to design complex free-form shapes such as airfoils and manifolds. It also merges solid and surface modeling techniques into one powerful tool set.

This self-guiding tutorial provides a step-by-step approach for users to learn Unigraphics. It is intended for those with no previous experience with Unigraphics. However, users of previous versions of Unigraphics may also find this tutorial useful for them to learn the new user interfaces and functions. The user will be guided from first starting a Unigraphics session to creating models and designs that have various applications. Each chapter has components explained with the help of various dialog boxes and screen images. These components are later used in the assembly modeling, machining and finite element analysis. These models of components are available online to download and use. We first released the Tutorial for Version 18 and later updated for NX-2. This write-up is further updated to Unigraphics NX-3.

http://web.umr.edu/~mleu/

If you have any questions or comments about this tutorial, please email Parthiban Delli at pdwt5@umr.edu. The Models and all the versions of the Tutorial are available at Unigraphics-NX3 for Engineering Design University of Missouri - Rolla 6

CHAPTER 1 - INTRODUCTION

The modern manufacturing environment can be characterized by the paradigm of delivering products of increasing variety, smaller lots and higher quality in the context of increasing global competition. Industries cannot survive worldwide competition unless they introduce new products with better quality, at lower costs and with shorter lead time. There is intensified international competition and decreased availability of skilled labor. With dramatic changes in computing power and wider availability of software tools for design and production, engineers are now using Computer Aided Design (CAD), Computer Aided Manufacturing (CAM) and Computer Aided Engineering (CAE) systems to automate their design and production processes. These technologies are now used everyday for engineering tasks. Below is a brief description of how CAD, CAM, and CAE technologies are used during the product realization process.

1.1 PRODUCT REALIZATION PROCESS

The product realization process can be divided into design and manufacturing. The design process starts with identification of a new design need that is identified after the marketing personnel gets feedback from customers’ demands. Once the relevant design information is gathered, design specifications are formulated. Next, a feasibility study is done with relevant design information. Detailed design and analyses then follow. Detailed design includes design conceptualization, prospective product drawings, sketches and geometric modeling. Analysis includes stress analysis, interference checking, kinematics analysis, mass property calculations and tolerance analysis, and design optimization. The quality of the results obtained from these activities is directly related to the quality of the analysis.

The manufacturing process starts with the shop-floor activities beginning from production planning, which uses the drawings from the design process and ends with the actual product. Process planning includes activities like production plan, material orders, and machine selection. There are varied tasks like procurement of new tools, NC programming and quality checks at various stages during production. Process planning includes planning for all these activities as well. Parts that pass the quality control inspections are assembled functionally tested, packaged, labeled, and shipped to customers.

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A diagram representing the Product Realization Process [1] is shown below. ([1] – CAD/CAM, by Ibrahim Zeid)

1.2 BRIEF HISTORY OF CAD/CAM DEVELOPMENT

The roots of today’s CAD/CAM technologies go back to the beginning of civilization when graphics communication was recognized by engineers in ancient Egypt. Orthographic projection practiced today was invented around the 1800s. The real development of CAD/CAM systems started in the 1950s. CAD/CAM went through four major phases of development in the last century. The 1950s was known as the era of interactive computer graphics. MIT’s Servo Mechanisms Laboratory demonstrated the concept of numerical control (NC) on a three axis milling machine. Development in this era was slowed down by the shortcomings of computers at the time. During the late 1950s the development of Automatically Programmed Tools (APT) began and General Motors explored the potential of interactive graphics.

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The 1960s was the most critical research period for interactive computer graphics. Ivan Sutherland developed a sketchpad system, which demonstrated the possibility of creating drawings and altercations of objects interactively on a cathode ray tube (CRT). The term CAD started to appear with the word ‘design’ extending beyond basic drafting concepts. General Motors announced their DAC-1 system and Bell Technologies introduced the GRAPHIC 1 remote display system.

During the 1970s, the research efforts of the past decade in computer graphics had begun to be fruitful, and important potential of interactive computer graphics in improving productivity was realized by industry, government and academia. The 1970s is characterized as the golden era for computer drafting and the beginning of ad hoc instrumental design applications. National Computer Graphics Association (NCGA) was formed and Initial Graphics Exchange Specification (IGES) was initiated.

In the 1980s new theories and algorithms evolved and integration of various elements of design and manufacturing was developed. The major research and development focus was to expand CAD/CAM systems beyond three-dimensional geometric designs and provide more engineering applications.

In the present day, CAD/CAM development is focused on efficient and fast integration and automation of various elements of design and manufacturing along with the development of new algorithms. There are many commercial CAD/CAM packages available for direct usages that are user-friendly and very proficient.

Here are some of the commercial packages in the present market.

• AutoCAD and Mechanical Desktop are some low end CAD softwares which are mainly used for 2D modeling and drawing.

• Unigraphics, Pro-E, Mechanical Desktop, CATIA and Euclid are higher order modeling and designing software that are costlier but more efficient. The other capabilities of these softwares are manufacturing and analysis.

• Ansys, Abaqus, Nastran, Fluent and CFX are packages mainly used for analysis of structures and fluids. Different software are used for different proposes. For example, Fluent is used for fluids and Ansys is used for structures.

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• Alibre, Cyber-Cut and CollabCAD are the latest CAD/CAM softwares which focus on collaborative design. Collaborative design is computer aided designing for multiple users working at the same time.

1.3 DEFINITION OF CAD/CAM/CAE

1.3.1 Computer Aided Design – CAD

CAD is technology concerned with using computer systems to assist in the creation, modification, analysis, and optimization of a design. Any computer program that embodies computer graphics and an application program facilitating engineering functions in design process can be classified as CAD software.

The most basic role of CAD is to define the geometry of design – a mechanical part, a product assembly, an architectural structure, an electronic circuit, a building layout, etc. The greatest benefits of CAD systems are that they can save considerable time and reduce errors caused by otherwise having to redefine the geometry of the design from scratch every time it is needed.

1.3.2 Computer Aided Manufacturing – CAM

operations through computer interface with the plant’s production resources

CAM technology involves computer systems that plan, manage, and control the manufacturing

One of the most important areas of CAM is numerical control (NC). This is the technique of using programmed instructions to control a machine tool that cuts, mills, grinds, punches or turns raw stock into a finished part. Another significant CAM function is in the programming of robots. Process planning is also a target of computer automation.

1.3.3 Computer Aided Engineering – CAE

CAE technology uses a computer system to analyze the functions of a CAD-created product, allowing designers to simulate and study how the product will behave so that the design can be refined and optimized.

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CAE tools are available for a number of different types of analyses. For example, kinematic analysis programs can be used to determine motion paths and linkage velocities in mechanisms. Dynamic analysis programs can be used to determine loads and displacements in complex assemblies such as automobiles. One of the most popular methods of analyses is using a Finite Element Method (FEM). This approach can be used to determine stress, deformation, heat transfer, magnetic field distribution, fluid flow, and other continuous field problems that are often too tough to solve with any other approach.

1.4 SCOPE OF THIS TUTORIAL

This tutorial is written for students and engineers who are interested in learning how to use Unigraphics for designing mechanical components and assemblies. Learning to use this software will also be valuable for learning how to use other CAD systems such as PRO-E and CATIA.

This tutorial provides a step-by-step approach for learning Unigraphics. The topics include Getting Started with Unigraphics, Form Features, Feature Operations, Drafting, Sketching, Free Form Features, Assembly Modeling, and Manufacturing.

Chapter 1 gives the overview of CAD/CAM/CAE. Here, the product realization cycle is discussed along with the history of CAD/CAM/CAE and the definitions of each.

other important commands, which will be used in later chapters

Chapter 2 includes the Unigraphics essentials from starting a session with Windows to getting familiar with the Unigraphics-NX3 layout by practicing basic functions such as Print, Save, and Exit. It also gives a brief description of the Coordinate System, Layers, various tool boxes and

The actual designing and modeling of parts begins with chapter 3. It describes different features such as reference features, swept features and primitive features and how these features are used to create designs.

Chapter 4 is a continuation of chapter 3 where various kinds of operations are performed on features. The different kinds of operations include Trim, Blend, Boolean operations and many more.

You will learn how to create a drawing from a part model in chapter 5. In this chapter, we demonstrate how to create a drawing by adding views, dimensioning the part drawings, and modifying various attributes in the drawing such as text size, arrow size and tolerance.

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