This article provides general guidelines for casting design to provide progressive solidification, minimize heat concentration, eliminate cores, and prevent distortion. Casting design also affects tolerances. Casting tolerances depend on the alloy being poured, the size of the casting, and the molding method used. Designers can predict the effect of the design on the structure of the final part using solidification simulation models, namely finite element and finite difference models, and rapid prototyping. The article concludes with a short note on how the quality is assured in the foundry.

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 three types of machining systems, namely, general-purpose machine tools, production machining systems, and computer numerically controlled (CNC) machining systems. It reviews 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.

This article describes design factors for products used in engineering applications. The article groups these factors into three categories: functional requirements, analysis of total life cycle, and other major factors. These categories intersect and overlap, constituting a major challenge in engineering design. Performance specifications, risk and hazard analysis, design process, design for manufacture and assembly, design for quality, reliability in design, and redesign are considered for functional requirements. Life-cycle analysis considers raw-material extraction from the earth and product manufacture, use, recycling (including design for recycling), and disposal. The other major factors considered include evaluation of the current state of the art for a given design, designing to codes and standards, and human factors/ergonomics.

Product design for manufacture and assembly can be the key to high productivity in all manufacturing industries. This article discusses the use of design for manufacture and assembly (DFMA) software in the evaluation of proposed designs. It summarizes the steps taken when using DFMA software during design. The article describes the use of design for analysis tool in reducing the number of separate parts, estimating assembly time, and determining design efficiency. It reviews assembly analysis methods such as the assemblability evaluation method, the assembly-oriented product design method, the Lucas method, and the design-for-assembly cost effectiveness method. The article explains the design for manufacture in terms of cost estimation and principal cost drivers. It provides information on the applications of DFMA and roadblocks in the implementation of DFMA. The article concludes with a discussion on the design for automatic assembly.

This article presents an overview of an engineering design process. Though the process is extremely complex, distinct stages of design activities are identified and described. The article illustrates guided iteration methodology that helps in problem solving in design. It describes the engineering conceptual design and configuration design of special-purpose parts. It discusses the parametric design methods of the parts and best practices that are used by successful firms to achieve the goals of quality, cost, time-to-market, and marketing flexibility.

Reliability-centered maintenance (RCM) is a systematic methodology for preventing failures. This article begins by discussing the history of RCM and uses Society of Automotive Engineers (SAE) all-industry standard JA1011 as its model to describe the key characteristics of an RCM process. It then expands on questions involved in RCM process, offering definitions when necessary. Next, the article describes the approach of RCM to failure modes and effects analysis (FMEA), the failure management policies available under RCM, and the criteria of RCM for deciding when a specific failure management policy is technically feasible. Then, after discussing the ways that RCM classifies failure effects in terms of consequences, it describes how RCM uses failure consequences to identify the best failure management policy for each failure mode. Next, the building blocks of RCM are put together to create a failure management program. The article ends with a discussion on some practical issues pertaining to RCM that lie outside the scope of SAE JA1011.

Reliability-centered maintenance (RCM) is a systematic methodology for preventing failures. This article discusses the history of RCM and describes the key characteristics of an RCM process, which involves asking seven questions. The first four questions comprise a form of failure modes and effects analysis (FMEA), and therefore, the article explains the approach of RCM to FMEA and the failure management policies available under RCM. It reviews the ways that RCM classifies failure effects in terms of consequences and details how RCM uses failure consequences to identify the best failure management policy for each failure mode. The article concludes with a discussion on some practical issues pertaining to RCM that lie outside the scope of SAE JA1011.

This article schematically illustrates a fiber placement system and provides information on the applications of fiber placement. It discusses materials and design considerations for fiber placement. The article provides information on techniques that can be used to eliminate areas of missing tows.

Blow molding has emerged as a commercially viable process for manufacturing parts for nonpackaging/industrial markets. This article discusses the machinery required, processing methods, mold types, process parameters, part designs and material distribution of blow molding. It provides an outline of the parison programming system equipped with blow molders to control the parison thickness. The article describes factors that are usually considered to minimize material distribution problems, namely, design, material selection, process control, part performance, and cost.

This article provides non-proprietary and non-competition-sensitive information related to aircraft applications. It presents an overview of reliability and commonly used measurements. Failure modes that cause the negative performance are reviewed based on many types of sources. These include manufacturer service bulletins, reliability and customer service departments, literature reviews, demonstration programs, in-service evaluations, design guides, and surveys of commercial and military aircraft maintenance organizations. The article also describes lessons learned while attempting to avoid overlapping maintainability, reparability, and materials choice.

Casting offers the cost advantages over other manufacturing methods for most components. This article reviews the aspects of castings with which designers should be familiar, as well as the methods used by foundries to produce high-integrity castings. It discusses the design concepts that designers and foundries can use to obtain maximum performance from cast parts. The article describes the effects of casting discontinuities on properties, including porosity, inclusions, hot tears, metal penetration, and surface defects. A discussion on hot isostatic pressing treatment of castings is also provided. The article concludes with information on solidification simulation and its use in designing castings.

This article describes selected U.S. environmental statutes and regulations that are pertinent to material surface finishers. It provides information on the applicability, requirements, and permitting conditions of the Clean Air Act, the Resources Conservation and Recovery Act, the Superfund Amendments and Reauthorization Act, and the Clean Water Act.

This article provides information on the development of finite element analysis (FEA) and describes the general-purpose applications of FEA software programs in structural and thermal, static and transient, and linear and nonlinear analyses. It discusses special-purpose finite element applications in piping and pressure vessel analysis, impact analysis, and microelectronics. The article describes the steps involved in the design process using the FEA. It concludes with two case histories that involve the use of FEA in failure analysis.

In materials selection, a decision matrix method refers to any formalized procedure by which materials are ranked prior to a selection decision. This article describes the advantages and limitations of decision matrix methods, as well as the steps involved, with examples. The methods include the Pugh method, the Dominic method, and the Pahl and Beitz method. The article discusses the three important concepts in decision making: alternatives (candidate materials), criteria (objectives), and weighting factors.

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 four types of constraints: numeric, geometric, algebraic, and attributes. It presents a discussion on data associativity and assembly design used in CAD system. 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.

When complex designs, transient loadings, and nonlinear material behavior must be evaluated, computer-based techniques are used. This is where the finite-element analysis (FEA) is most applicable and provides considerable assistance in design analysis as well as failure analysis. This article provides a general view on the applicability of finite-element modeling in conducting analyses of failed components. It highlights the uses of finite-element modeling in the area of failure analysis and design, with emphasis on structural analysis. The discussion covers the general development and both general- and special-purpose applications of FEA. The special-purpose applications of FEA covered are piping and pressure vessel analysis, impact analysis, and microelectronic and microelectromechanical systems analysis. The article provides case histories that involved the use of FEA in failure analysis.

The design process for ceramic materials is more complex than that of metals because of low-strain tolerance, low fracture toughness and brittleness. The application of structural ceramics to engineering systems hinges on the functional benefits to be derived and is manifested in the conceptual design for acceptable reliability. This article discusses the design considerations for the use of structural ceramics for engineering applications. It describes the conceptual design and deals with fast fracture reliability, lifetime reliability, joints, attachments, interfaces, and thermal shock in detailed design procedure. The article provides information on the proof testing of ceramics, and presents a short note on public domain software that helps determine the reliability of a loaded ceramic component. The article concludes with several design scenarios for gas turbine components, turbine wheels, ceramic valves, and sliding parts.

This article begins with information on the fundamentals of chip formation process and general considerations for the modeling and simulation of machining processes. It focuses on smaller-scale models that seek to characterize the workpiece/tool/chip interface and behaviors closely associated with that. The article describes the advantages and disadvantages of various finite-element modeling approaches, namely, transient models, continuous cutting model, steady-state model, hybrid model, two-dimensional models, and three-dimensional models. It discusses flow stress measurements using constitutive and inverse testing methods and reviews tool design for chip removal. The article explains the effect of tool geometry on burr formation and the effect of coatings on tool temperatures. It concludes with information on tool wear, which is an unavoidable effect of metal cutting.

This article discusses the requirements for designing repairable composite structures such as a honeycomb sandwich panel construction and integrally stiffened co-cured composite structures. It reviews the general and specific design guidelines for bolted or riveted repairs and adhesively bonded repairs of the composite structures. The article presents several examples to illustrate how these repairs can be achieved.

This article provides a summary of the overall development of the finite element method (FEM) and its contribution to the materials forming industry. It focuses on the overall philosophy and evolution of the FEM for solving bulk forming issues. A number of applications of FEM are presented in the order they would be used in a typical manufacturing process sequence: primary materials processing, hot forging and cold forming, and product assembly. The article discusses four FEM modules: the deformation model, the heat-transfer model, the microstructural model, and the carbon diffusion model. The article also covers material fracture and die stress analysis and reviews optimization of the design of forming processes.