Modern, solids-based computer-aided design/computer-aided manufacturing (CAD/CAM) systems provide a good share of what is needed for companies to develop products using modern methods. This article provides a brief history and an overview of CAD technology. Form features combined with constraint parameters have greatly simplified how designers work with solid modelers to design parts and assemblies. The article describes the four types of constraints, namely, numeric, geometric, algebraic, and attributes. It provides a discussion on data associativity and assembly design used in CAD system. CAD/CAM systems provide much more than the definition of the solid model as a design. The article provides information on the applications of CAD systems, including integrated product development, drafting and product documentation, product visualization, mechanical analysis, and numerical control programming.

This article describes grade designations of the various sheet steels used for draw forming. It discusses the specifications associated with most sheet draw forming materials. The article examines the behavior of stress- and strain-based forming limit curve (FLC). It provides a discussion on three separate frictional conditions acting in a draw die. The frictional conditions include the metal passing through a draw bead, the metal clamped in the binder, and the metal sliding across a die radius. The article also explains the basic steps in the vehicle development process. The steps involved in the thought process of direct engineering for formability are also explained. The article places considerable emphasis on the need for the designer to clearly define the die/tooling faces in the computer-aided design (CAD)/computer-aided manufacturing (CAM) system before the data are passed on to the construction functions.

This article describes the basic functions that should be included when considering the relationship of computer-aided design (CAD)/computer-aided manufacturing (CAM) and machining. These include design, analysis, drafting, process planning, part programming, program verification, part machining, and inspection. The article provides information on hardware, data base, interfaces, and benefits of integrating machining with the CAD/CAM system of a manufacturing plant. It also provides an overview of direct, computer and, distributed numerical control, which are devoid of a number of problems inherent in conventional numerical control.

Solid modeling is the act of creating the three-dimensional models of various components and system using a computer-aided design (CAD) tool. This article describes the fundamental approaches of solid modeling, such as manufacturing operation simulation, parametric approach, and reference entities. It discusses the application of solid modeling systems to create expressions or variables and various surfaces for components. The use of high-end CAD systems to afford a number of sheet metal functions is reviewed. The article explains the explicit-parametric modeling and model verification for the solid modeling. It provides information on the application of solid modeling in associativity and concurrent engineering, product lifecycle management, and collaborative engineering.

The success of a reliable non-destructive evaluation (NDE) application depends greatly on the expertise and thoroughness of the NDE engineering that is performed. This article discusses the general considerations of NDE in terms of NDE response and NDE system management and schedule. It describes the NDE engineering and NDE process control, along with some case studies related to the applications of NDE. The article reviews various models for predicting NDE reliability, such as ultrasonic inspection model, eddy current inspection model, and radiographic inspection model. It concludes with an example that illustrates the integration of an ultrasonic reliability model with a CAD system.

Chemical-mechanical planarization (CMP) of metals is described as mechanically accelerated corrosion, erosion corrosion, or metallic corrosion enhanced by wear. This article reviews the history, process, chemistry, electrochemistry, and defect issues for CMP. It provides an overview of CMP through a schematic illustration of CMP process equipment. The applications of CMP to tungsten and copper alloys are of prime interest in the semiconductor industry. The article discusses copper CMP and tungsten CMP in detail and analyzes polishing mechanism during CMP by application of direct current potentiodynamic polarization and alternating current impedance measurements. It concludes with information on chemically induced defects such as pitting corrosion, galvanic corrosion, and chemical etching.

This article discusses the types of adaptive control (AC) systems for metal cutting according to the AC strategies used. These include adaptive control with optimization (ACO), adaptive control with constraints (ACC), and geometric adaptive control (GAC). The article details the milling and grinding systems based on the ACO strategy. It reviews the fundamentals of ACC systems followed by a description of a particular ACC system for a turning operation. The article also describes the basic characteristics of GAC systems and presents a particular GAC system for the turning of cylindrical parts. It examines the issues in the AC systems such as tool wear/breakage. Trends in the AC systems such as variable-gain ACC systems and integration of adaptive control into CAD/CAM/CIM systems are also discussed.

This article presents an overview of the use of mechanism analysis (kinematics and dynamics) and simulation. It provides indications of the directions in which mechanism simulation is growing and how it is integrated in the evolving computer aided design and computer aided engineering (CAD/CAE) fields. Mechanism simulation is best used as part of a concurrent CAD/CAE approach to design. The article discusses the state, evolution, and direction of application for these techniques in a variety of fields.

This article focuses on the use of electron beam (EB) for near-net shape processing based on the wire feed material-delivery method. EB deposition processes start with a 3-D model designed in a computer-aided design (CAD) environment, where the deposition path and process parameters are generated. The article provides a description of the electron beam direct manufacturing (EBDM) system used for manufacturing of target parts with the aid of a case study. The control of the essential variables of dynamic beam deflection is also reviewed. The article also includes information on the applications of high-frequency multibeam processes, namely, selective surface treatment, multiple-pool welding, and pre- and post-heat treating.

Hot extrusion is a process in which wrought parts are formed by forcing a heated billet through a shaped die opening. This article discusses nonlubricated and lubricated hot extrusion. The two nonlubricated hot extrusion methods are forward or direct extrusion and backward or indirect extrusion. The article illustrates the significance of extrusion speeds and temperatures in hot extrusion. It describes the basic types of presses used in the hot extrusion of metals. The article provides information on the characterization of extruded shapes and explains the operating parameters, including extrusion velocity, amount of pressure required, and type of lubricant, for successful and efficient hot extrusion. The article concludes with a discussion on applications and design methodology that provides insight into CAD/CAM of extrusion dies.

This article focuses on the methods that are being developed for detecting and monitoring corrosion: electrochemical methods, electromagnetic or sound wave methods, fiber-optic technology, fluorescence methods, and the Diffracto Sight method. It reviews the importance of data management and the Corrosion Expert System. It concludes with information on the simulation and modeling for incorporating the mechanisms of corrosion prevention into military hardware systems design and operation.

This article provides an overview of finite-element-based analyses (FEA) of advanced composite structures and highlights the key aspects, such as homogenization of materials properties and post-processing of numerical results. It discusses the analysis of composite structures based on micromechanics and macromechanics. The article describes the FEA of 3-D solid elements, 2-D cylindrical shell elements, and 1-D beam elements. It contains a table that lists the commercially available finite element codes related to the analysis of fibrous composite materials. The article presents classical examples from the mechanics of composite materials to illustrate the aspects of multilayered composite structures.

This article provides information on single-shot and scanning, the two types of induction heat treating processes that are based on whether the induction coil is moving relative to the part during the heating process. It describes the effect of the frequency of induction heating current on the induction coil and process design, and the control of heating in different areas of the inductor part. The article reviews three main tools for adjustment of coil design and fabrication: coupling gap, coil copper profile, and magnetic flux controllers. It examines the method of holding a part and presenting it to the inductor during the initial inductor design. The article provides information on coil leads/busswork and contacts that mechanically and electrically connect the induction coil head to the power supply. It concludes with a discussion on flux and oxide removal, leak and flow checking, silver plating, and electrical parameter measurement.

Machining or material removal processes are secondary manufacturing operations that are used to achieve precise tolerances or to impart controlled surface finishes to a part. This article summarizes rules for designing parts to improve machined part quality and reduce machining costs in mass and batch production environments. It discusses the factors affecting the total cost of a machining operation, including raw material costs, labor costs, and equipment costs. The article describes the three types of machining systems, namely, general-purpose machine tools, production machining systems, and computer numerically controlled (CNC) machining systems. It discusses general design-for-machining rules that are applicable to all parts, regardless of the type of equipment used to produce them. Special considerations for production machining systems and CNC machining systems are discussed. The article describes the structure and typical uses of computer-aided process planning and design-for-manufacturing programs.

Material extrusion systems are the most common types of additive manufacturing systems, also known as three-dimensional (3D) printers. This article focuses on the general 3D printing processes as can be demonstrated and manipulated in desktop printers. The discussion includes details of the components involved in material extrusion as well as the melt extrusion solidification (during cooling) process, the underlying mechanism of road bonding, and the factors affecting good part quality. The discussion also covers support material, postprocessing, and road-quality considerations and the addition of infill in melt extrusion to the hollow spaces inside an object to give it structural strength. Information is also provided on different materials and associated material properties that affect the rate the printer is able to advance and retract material, thereby affecting the quality and rate at which a part is printed. The final section provides information on the mechanism of viscous extrusion 3D printing.

This article provides a description of various systems for computer-aided materials selection that deals primarily with promising prototypes that have emerged for various applications. These include expert systems, quantitative selection systems, qualitative and experiential selection systems, and object-oriented systems.

Efforts in improving the efficiency of automated equipment lead to combining automatic joining equipment with a modem computer technique eventually known as artificial intelligence (intelligent automation) that usually includes an off-line planning system and a real-time adaptive control system connected through a computer communications interface. This article focuses on the application of intelligent automation system to arc welding, called WELDEXCELL, and other joining processes. An outline of the interface between off-line planners and real-time control systems is also provided.

This article discusses four subsystems of the electrochemical machining (ECM) system: power source, electrolyte cleaning and supply system, tool and tool-feed system, and workpiece and workpiece-holding system. It describes the theory of ECM and provides information on the electrolytes used in ECM. The article reviews the methods associated with workpiece shape prediction. The procedures and integrated approach for the tool design in ECM are discussed. The article also explains the process control, capabilities, and the limitations of ECM. It concludes with information on the applications of ECM.

Machine vision, also referred to as computer vision or intelligent vision, is a means of simulating the image recognition and analysis capabilities of the human eye and brain system with digital techniques. The machine vision functionality is extremely useful in inspection, supervision, and quality control applications. This article presents a variety of machine vision functions for different purposes and provides a comparison of machine and human vision capabilities in a table. It discusses the processes of a machine vision system: image acquisition, image preprocessing, image analysis, and image interpretation. The article provides information on the uses of machine vision systems in three categories of manufacturing applications: visual inspection, identification of parts, and guidance and control applications.

Green sand molding and chemically bonded sand molding are considered to be the most basic and widely used mold-making processes. This article describes the sand system formulation, preparation, mulling, mold fabrication, and handling of green sand molds. It lists the advantages and disadvantages of green sand molding. The article discusses the primary control parameters for the sand system formulation. It describes two basic types of green sand molds such as flask molds and flaskless molds. The article provides a discussion on molding problems including springback and expansion defects. It discusses a variety of sand reclamation systems, including wet washing/scrubbing and thermal-calcining/thermal-dry scrubbing combinations.