Integration of CAD/CAPP/CAM

Jianbin Xue

• Publisher: De Gruyter
• Year: 2018
• Print ISBN:
  9783110573084
• eBook ISBN:
  9783110573213
• Topic: Computer Science
• Subtopic: Information Management
• Index: Computer Science

The book introduces the fundamentals and development of Computer aided design, Computer aided process planning, and Computer aided manufacturing. The integration of CAD/CAPP/CAM, product data management and Concurrent engineering and collaborative design etc. are also illustrated in detail, which make this book be an essential reference for graduate students, scientists and practitioner in the research fields of computer sciences and engineering.

1 Introduction

Questions before you read

1. Do you know anything about CAD, CAPP, and CAM?
2. What is the whole product life cycle?
3. How do you plan to carry out product design and manufacture?
4. What kinds of software packages do you need in product design and manufacture?

The goal of this chapter is to help the reader understand the basic concept of integration of CAD/CAPP/CAM, their roles in the whole product life cycle, and the brief history of the isolated systems. The concepts of product data management (PDM) and concurrent engineering (CE) are also briefly introduced in this chapter.

1.1 Product design and manufacture

Do you ever want to design and manufacture a product? During your childhood, you must have been attracted by some amazing products. You want to make it. However, your knowledge was limited at that time. You admired the carpenters who could make a number of products of wood. You also admired the blacksmiths who could make tools of steel. And now there are a large number of factories making many products of different materials every day. Do you have such an intention to find out how these products were made of? Here you will be given a general description about the product life cycle.

Product life cycle

In the field of economics, the product life cycle has been divided into four stages: introduction, growth, maturity and decline. But in this textbook, the product life cycle means the product development life cycle, which is a complex procedure, as illustrated in Figure 1.1. The product begins with a need based on customers’ demands. From the voice of customers to market analysis, product design, process planning, product manufacture, sales, use and discard. The first two blocks and the last two blocks are mostly related to markets, sales and services, which can be classified into the management field. The product design, process planning and product manufacture are closely related to mechanical engineering, so these three blocks can be classified into the engineering field. The main contents of this textbook cover these three blocks: product design, process planning and product manufacture. With the development of computer science and technology, computers are used to help engineers in different stages of product development. So computer-aided design (CAD) is the automation of product design; computer-aided process planning (CAPP) is the automation of process planning; and computer-aided manufacturing (CAM) is the automation of product manufacture. This textbook introduces the integration of CAD/CAPP/CAM. The interfaces between the product design, process planning and product manufacture are described and analyzed.

Figure 1.1: Product life cycle.

Basic concept of CAD/CAPP/CAM

Global competitions are increasing in modern manufacturing environment. Products should be delivered with increasing variety, smaller lots and higher quality. Industrial companies cannot survive worldwide competition unless they introduce new products with better quality, at lower costs, and with shorter lead-time. The availability of skilled labor is decreasing. With dramatic changes in computing power and software tools for design and production, engineers are now using CAD, CAPP, CAM, and computer-aided engineering (CAE) systems to automate their design and production processes. And industrial robots are widely used in most manufacturing companies to replace skilled human labor. These technologies are now used every day for engineering tasks. Below is a brief description that how CAD, CAPP, CAM, and CAE technologies are used during the product realization process.

The term CAD/CAPP/CAM is a shortened form of integration of CAD, CAPP and CAM. CAD and CAM are two essential tools to design and manufacture parts. CAPP is trying to bridge the two systems by seamless integration. In recent years, CAE is becoming popular. And it must be also integrated with other CAD/CAPP/CAM systems. So the integration of CAD/CAPP/CAM should be extended to be CAD/CAPP/CAM/CAE. Even more, the integration of CAD/CAPP/CAM should also consider the aspect of robots.

There are several main tasks to be finished, respectively, in each stage. Figure 1.2 shows the main tasks of the three stages.

Figure 1.2: Design, process planning and manufacture.

In the stage of product design, CAD software packages are the main tools. CAD systems are used for geometric modeling, engineering analysis, simulation, scientific computing, graphics, and engineering database. Reverse engineering is a new approach for product design. With the development of network, CAD is also used to communicate among or between different engineers from different departments.

In the stage of process planning, CAPP software packages are the main tools. CAPP systems help engineers carry out rough casting design, machining process selection, operation design, routing design, ration of man-hour, tooling, and fixture and jigs.

In the product manufacture stage, CAM software packages are the main tools. CAM systems are used for numerical control (NC) programming, tool path planning, cutting data files, simulation of tool path, NC code verification, check out and trial manufacture. Three-dimensional printing is a new method for product manufacture; it is a kind of additive manufacturing.

Computer applications have been found in the entire spectrum of the product development process, ranging from conceptual design to product realization, and even recycling. CAD, CAPP, and CAM could have been independent systems. They are now seamlessly integrated as CAD/CAPP/CAM because most of the common information about products must be shared among them. So the main point is the integration, which is expressed using the forward slash (/) symbol. Here, the forward slashes among the three or four CAx systems play more important roles in the development of products. They represent the integration relationships among these systems.

1.2 Development of CAD/CAPP/CAM

1.2.1 Computer-aided design

CAD is mainly used for detailed two-dimensional engineering drawings of physical components, and for 3D modeling since the 1980s, but it is also used throughout the engineering process from conceptual design and layout of products, through strength and dynamic analysis of assemblies to definition of manufacturing methods of components.

With the advent of computers, designers have long used computers for their calculations. Initial developments were carried out in the 1960s within the aircraft and automotive industries in the area of 3D surface construction and NC programming, most of it independent of one another and often not publicly published until much later.

First commercial applications of CAD were in large companies such as the automotive and aerospace industries, as well as in electronic industries. Because computers were very expensive, only large corporations could afford the computers capable of performing the calculations.

As computers became more affordable, the application areas have gradually expanded. The personal computers dropped the prices of computers. The development of CAD software for personal computers was the right impetus for almost universal application in all areas.

CAD implementations have evolved dramatically since then. Initially, with 2D in the 1970s, it was typically limited to producing drawings similar to hand-drafted drawings. Advances in programming and computer hardware, notably solid modeling in the 1980s, have allowed more versatile applications of computers in design activities. Some key products for 1981 were the solid modeling packages – Romulus (ShapeData), Uni-Solid (Unigraphics) based on PADL-2, and the release of the surface modeler CATIA (Dassault Systèmes).

Autodesk was found in 1982, which developed a 2D system named Auto CAD. Following the idea of 2D drawing, the computer aided x alliance (CAXA) system was developed to throw off the drawing board in China. The next milestone was the release of Pro/Engineer in 1988, which used the feature-based modeling methods. Also of importance to the development of CAD was the development of the B-rep solid modeling kernels (engines for manipulating geometrically and topologically consistent 3D objects), Parasolid (Shape Data), and ACIS (Spatial Technology Inc.) at the end of the 1980s and the beginning of the 1990s. This led to the release of mid-range packages such as SolidWorks in 1995, Solid Edge (Intergraph) in 1996, and Iron CAD in 1998. Since the beginning of the 21st century, these packages have been enriched with many functional modules. Some big buyouts happened to reorganize the CAD market. In 1997, Dassault Systèmes, best known for its CATIA CAD software, acquired SolidWorks for $310 million in stock. In 2000, Unigraphics purchased structural dynamics research corporation (SDRC) I-DEAS and integrated aspects of both software packages into a single product when became Unigraphics NX. Since 2007, NX has been owned by Siemens PLM Software.

Starting the late 1980s, CAD programs could be run on personal computers. The drafting departments in many small to middle enterprises were massively downsizing. As a general rule, one CAD operator could readily replace at least four or five drafters using traditional ruler–pencil methods. Additionally, many engineers began to do their own drafting work, further eliminating the need for traditional drafting departments. This trend mirrored that of the elimination of many office jobs traditionally performed by a secretary as word processors, spreadsheets, databases, and so on became standard software packages that everyone was expected to learn.

Today, CAD is not limited to drafting and rendering, and it ventures into many more “intellectual” areas of a designer’s expertise. CAD is used in many businesses and organizations around the world.

1.2.2 Computer-aided manufacturing

CAD has steadily advanced over the past seven decades to the stage at which designs for new products can be made entirely within the framework of CAD software from the development of the basic design to the bill of materials necessary to manufacture the product. But at this stage, manufacturing has not been considered carefully.

CAM takes this one step further from the conceptual design to the manufacturing of the finished product. Whereas in the past it would be necessary for design developed using 2D CAD software to be manually converted into a drafted paper-drawing detailing instructions for its manufacture, CAM software allows data from 2D CAD software to be converted directly into a set of manufacturing instructions.

Afterward, CAM software converts 3D models generated in CAD into a set of basic operating instructions written in G-code directly. G-code is a programming language that can be understood by numerically controlled machine tools. The G-code can instruct the machine tool to manufacture a large number of items with perfect precision and faith to the CAD design. G-code has a history about 70 years. Figure 1.3 shows a CNC machine tool, which can understand G-code from CAM.

Figure 1.3: A CNC machine tool understanding G-code from CAM.

Modern numerically controlled machine tools can be linked into a flexible manufacturing cell (FMC), a collection of tools that each performs a specified task in the manufacture of a product. The product is passed along the cell in the manner of a production line, with each machine tool, that is, welding and milling machines, drills, and lathes, performing a single step of the process.

For the sake ...

Table of contents

• Cover
• Title Page
• Copyright
• Contents
• 1 Introduction
• 2 Computer-aided design
• 3 Computer-aided process planning
• 4 Computer aided manufacturing
• 5 Integration of CAD/CAPP/CAM
• 6 Product data management
• 7 Concurrent engineering and collaborative design
• 8 The future
• Index