This article describes the laboratory techniques for direct measurement and quantification of die wear in verifying a proprietary die-wear predictor methodology. This method is based on a theoretical formula that can be used to predict the rate of die wear and the life of a die surface coating, applicable to both mild steel and high-strength steels stampings. The article discusses the behavior of the surface conditions through quantitative measurements and surface analyses conducted throughout the wear tests. The surface conditions include surface roughness, surface morphology, microstructure, interfacial friction, surface temperatures, and wear rate.

This article provides information on the classification of high-strength steels (HSS) and advanced high-strength steels (AHSS) and tabulates designation of HSS and AHSS as recommended by the American Iron and Steel Institute. It reviews the major grades of HSS and AHSS that are used or will potentially be used in industrial applications. The article discusses different stamping issues such as edge cracking and springback, encountered during forming of AHSS, and lists guidelines for reducing springback in stamped components. It concludes with a discussion on the major advantages and disadvantages of using HSS and AHSS in automotive applications.

The multiple-slide machine, sometimes called a four-way, four-slide, or multislide machine, is a somewhat specialized item of stamping equipment, although it is very versatile within a limited area of stamping applications. This article discusses the construction and advantages of multiple-slide machines. It presents comparisons of four-slide operations with press operations based on production speed, tooling cost, tool adjustments, and operating cost. The article reviews some factors to be considered while selecting multiple-slide machines. It summarizes the strip materials commonly used in four-slide production. The article examines the design factors of four-slide parts, including tolerances and finishes. It provides the design recommendations for optimal part quality at maximum production speed. The article also discusses various four-slide cutoff methods.

Sheet forming failures divert resources from normal business activities and have significant bottom-line impact. This article focuses on the formation, causes, and limitations of four primary categories of sheet forming failures, namely necks, fractures/splits/cracks, wrinkles/loose metal, and springback/dimensional. It discusses the processes involved in analytical tools that aid in characterizing the state of a formed part. In addition, information on draw panel analysis and troubleshooting of sheet forming failures is also provided.

The measurement techniques for die wear can be classified into the following two categories: direct measurements, which are done using lab techniques; and indirect nondestructive measurements, which are done by plant monitoring. This article describes the details of the plant monitoring techniques, along with comprehensive discussions on the measured wear data based on roughness and hardness of die surfaces. It presents a comparison between the predicted and measured die wear rates.

Fabrication of high-density heat exchangers, which have a large heat transfer area and a compact size, is best accomplished by brazing where the brazing filler metal is clad to the materials to be brazed. This article focuses on the brazing procedures involved in the fabrication of high-density heat exchangers. The brazing procedures include base metal and brazing filler metal selection; fabrication of clad brazing materials; and stamping, cleaning, and assembling of cladded parts. The article concludes with an examination of brazing parameters.

Fine-blanking is a hybrid metal forming process that combines the technologies of stamping and cold extrusion. This article describes the three principal design features of the fine blanking process: the vee-ring, clearance between punch and die, and counterforce imposed by the ejector. It discusses the advantages and disadvantages of edge blanking and materials. The article reviews the classification of fine-blanking dies such as the moving-punch system and the fixed-punch system, and provides information on the mechanical and hydraulic fine-blanking presses.

This article briefly reviews the forming of steel tailor-welded blanks (TWB) with a discussion on the effects of welding on forming. It presents the parameters that are monitored to control the stamping operation for tailor-welded blanks. The article discusses weld factors such as the orientation of weld relative to metal movement in dies, the formability of TWB materials, die and press considerations, and specific factors for the drawing, stretching, and bending of steel tailor-welded blanks.

This article discusses the presses, auxiliary equipment, and dies used in the blanking and piercing of commonly used magnetically soft materials, namely, low-carbon electrical steels and oriented and nonoriented silicon electrical steels. It describes the effect of stock thickness and work metal composition and condition on blanking and piercing. The article provides an overview of the influence of burr height on stacking factors and presents a discussion on the lubrication and core plating of electrical steels that ease the process.

This article focuses on the technology breakthroughs that make forming simulation a routine work throughout the industry. It discusses many forms of the computer-aided engineering (CAE) methodology. The article describes several failure criteria to predict the failure of sheet metal. It explains the numerical procedure for sheet metal forming and reviews the important technical issues in CAE simulations. The article provides information on the applications and process of metal-forming simulation. It also reviews the capabilities of major systems that are popular among sheet metal forming users worldwide.

Statistics are extremely important tools in the operation of press shops, providing numerical process analysis capabilities. The most common use of statistics in the press shop is statistical process control (SPC) that uses statistical techniques such as control charts to analyze a process or its output to enable appropriate actions to be taken to achieve and maintain a state of statistical control. This article discusses the role of statistics in sheet metal forming operations, both in terms of SPC techniques, such as control charting, statistical deformation control, and experimental design, including single-variable studies, multivariable studies, and Taguchi experiments.

This article reviews the production variables that influence the selection of various stamping die materials: ferrous, nonferrous, and plastic die materials. It provides a discussion on the specific types of die materials for tool steels, cast irons, plastics, aluminum, bronze, zinc-aluminum, and steel-bonded carbides. The article describes factors to be considered during the selection of materials for press-forming dies.

This article characterizes the physical differences between powder metallurgy (PM) and wrought or cast materials, as they apply to joining. It discusses acceptable joining procedures and techniques, including welding and brazing and solid-state methods. Information on the weldability of various PM materials is presented. The article also describes the effects of porosity on several important properties that affect the welding characteristics.

Sheet metal forming operations are so diverse in type, extent, and rate that no single test provides an accurate indication of the formability of a material in all situations. This article presents an overview of types of forming, formability problems, and principal methods of measuring deformation. It reviews the effect of materials properties and temperature on formability. The article provides a detailed discussion on the two major categories of formability tests such as the intrinsic test, including uniaxial tension testing, plane-strain tension testing, biaxial stretch testing, and simulative tests such as bending tests, stretching tests, the Ohio State University test, the drawing test, and stretch-drawing tests. It extends the correlation between simulative tests and materials properties using forming limit diagrams and circle grid analysis, and discusses the improvements to the forming limit diagram technology.

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 begins with a discussion on the fundamentals of cutting. It focuses on blanking and piercing operations in a press tool to form and shape the final part geometry. The types of piercing operations include conventional piercing, piercing with a pointed punch, piece-and-extrude operations, slotting, countersinking, and cutting and lancing of tabs. The article provides information on the punch assembly, the die assembly, and the stripper and discusses the factors considered during piercing operations. It reviews the applications of the four types of blanks used in sheet-forming operations, namely, rectangular blank, rough blank, partially developed blank, and fully developed blank. It concludes with a discussion on the process capabilities, applications, and limitations of fine-edge blanking and piercing.

The powder metallurgy (P/M) process has been used primarily for the production of advanced high-speed tool steels. However, the P/M process is also being applied to the manufacture of improved cold-work and hot-work tool steels. The basic heat treatments for P/M high-speed tool steels include preheating, austenitizing, quenching, and tempering. This article describes manufacturing properties, cutting tool properties, and applications of P/M high-speed tool steels. It discusses the development of P/M high-speed alloy steels that cannot be made by conventional methods because of their high carbon, nitrogen, or alloy contents. For high-speed tool steels, a number of important end-user properties have been improved by powder processing; machinability, grindability, dimensional control during heat treatment, and cutting performance under difficult conditions where high edge toughness is essential. Several of these advantages also apply to P/M cold- and hot-work tool steels, which, compared to conventional tool steels, offer better toughness and ductility for cold-work tooling, better thermal fatigue life, and greater toughness for hot-work tooling.

Sheet forming comprises deformation processes in which a metal blank is shaped by tools or dies, primarily under the action of tensile stresses. This article discusses the classification of sheet-forming processes for obtaining desired dimensional features. It describes different process-related developments, namely, superplastic forming of aluminum, forming of tailor-welded blanks, rubber-pad forming, and high-velocity metal forming. The article explains cost-effective approaches of evaluating tooling designs prior to the manufacture of expensive steel dies and dieless forming techniques such as thermal forming and peen forming. It provides information on the application of advanced high-strength steels, magnesium alloys, and various ultrafine-grain materials for superplastic sheet forming. The article concludes with information on the development and application of simulation, design, and control of sheet-forming processes.

This article emphasizes the traits that are common to high-velocity forming operations. It describes general principles on how metal forming is accomplished and analyzed when inertial forces are large. The article discusses the principal methods of high-velocity forming, such as explosive forming, electrohydraulic forming, and electromagnetic forming. It provides examples that illustrate how these methods can be practically applied. The article concludes with information on the status and development potential for the technology.

The compression molding process is most commonly called the sheet molding compound (SMC) process in reference to the precursor sheet molding compound material it uses. This article discusses the types of materials used for sheet manufacture, and describes the manufacturing and processing parameters of SMC components, providing details on tooling and process advantages and limitations. The article provides a general overview of the types of compression molding processes, including structural compression molding and thermoplastic compression molding.