This article describes strain analysis techniques for troubleshooting formability and process discrepancies throughout a tooling development and production stamping cycle. The techniques include strain calculations of a flat blank, forming limit curve, and forming limit diagram. The article describes the types of strain analysis, namely, thinning strain analysis and circle grid strain analysis. It also provides information on the applications of the thinning strain analysis.

Shearing is a process of cutting flat product with blades, rotary cutters, or with the aid of a blanking or punching die. This article commences with a description of some wear and material factors for tools used to shear flat product, principally sheet. Methods of wear control are reviewed in terms of tool materials, coatings and surface treatments, and lubrication. The article discusses tool steels that are used for cold and hot shearing, and rotary slitting. It provides information on the materials used for two main categories of machine knives: circular knives and straight knife cutters. The article also discusses the selection of materials for blanking and piercing dies and provides examples that illustrate the various types of tooling changes for blanking high-carbon steel.

This article illustrates the mechanics of the deep drawing of a cylindrical cup. It discusses the fundamentals of drawing and drawability. Sheet metal is drawn in either hydraulic or mechanical presses. The article summarizes the defects in drawing and factors considered in press selection for drawing. It explains the types of dies used for drawing sheet metal and the effects of process variables and material variables on deep drawing. The process variables that affect the success or failure of a deep-drawing operation include the punch and die radii, punch-to-die clearance, press speed, lubrication, and type of restraint of metal flow used. The article describes the process of redrawing and ironing of metals. Drawing of workpieces with flanges and drawing of hemispheres are also illustrated. The article also provides information on the reducing of drawn shells, methods for expanding portions of drawn workpieces, trimming, and deep drawing using fluid-forming presses.

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.

Metal spinning is a term used to describe the forming of metal into seamless, axisymmetric shapes by a combination of rotational motion and force. This article describes two forming techniques, such as manual spinning and power spinning, for forming seamless metal components. The process technology, equipment, and tooling for both manual spinning and power spinning are also discussed.

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 discusses the mill products most often formed by the three-roll forming process. It schematically illustrates some of the shapes commonly produced from flat stock by the three-roll forming process. The article describes the two basic types of three-roll forming machines, namely, the pinch-roll type and the pyramid-roll type. It also lists the advantages of the pinch-roll machine, as compared to the pyramid-roll machine. The article analyzes the hot forming and cold forming processes for carbon or low alloy steel. It explains the procedure for forming truncated cones, bars, and bar sections by utilizing the pyramid-roll machine.

This article illustrates the characteristics of pierced holes and summarizes the hole wall quality. Specific guidance in selecting die clearances is provided by considering the types of edges produced with different clearances. The article discusses the effect of tool dulling and the use of small and large clearance. It informs that the force needed to pierce a given material depends on the shear strength of the work metal, the peripheral size of the hole or holes to be pierced, stock thickness, and depth of shear on the punch. The article discusses the presses and tools used in piercing. It illustrates the use of compound dies, progressive dies, and transfer dies; piercing of thick and thin stock and piercing holes at an angle to the surface; special piercing techniques; and shaving of low-carbon steels.

This article discusses the production of blanks from low-carbon steel sheet and strip in dies in a mechanical or hydraulic press. It describes the cutting operations that are done by dies in presses to produce blanks. The applications of blanking methods are described with examples. The article reviews the characteristics of blanked edges and explains how to calculate the forces and the work involved in blanking. Factors affecting the processing of blanks are discussed. The article provides information on the selection of work metal form, the effect of work metal thickness on the selection of material for dies and related components, as well as the selection of die type and design. The article illustrates the construction and use of short-run dies and conventional dies. It concludes with information on the shaving and deburring methods for blanking.

This article discusses the general formability considerations of aluminum alloys. To conduct a complete analysis of a formed part, the required mechanical properties, as determined by several standard tests, must be considered. The article describes tension testing and other tests designed to simulate various production forming processes, including cup tests and bend tests, which help in determining these properties. It provides information on the equipment and tools, which are used in the forming of aluminum alloys. The article presents a list of lubricants that are most widely used in the forming. It also analyzes the various forming processes of aluminum alloys. The processes include blanking and piercing, bending, press-brake forming, contour roll forming, deep drawing, spinning, stretch forming, rubber-pad forming, warm forming, superplastic forming, explosive forming, electrohydraulic forming, electromagnetic forming, hydraulic forming, shot peening, and drop hammer forming.

Thread rolling is a cold-forming process for producing threads or other helical or annular forms by rolling the impression of hardened steel dies into the surface of a cylindrical or conical blank. Methods that use cylindrical dies are classified as radial infeed, tangential feed, through feed, planetary, and internal. This article focuses on the capabilities, limitations, and machines used for these methods. It describes the three characteristics, such as rollability, flaking, and seaming, used in evaluating and selecting metals for thread rolling. The article explores the factors affecting die life and explains the effect of thread form on processing. It provides information on various fluids used in thread rolling to cool the dies and the work and to improve the finish on the rolled products. The article provides a comparison between thread rolling and cutting, as well as between thread rolling and grinding.

This article discusses the three characteristics that are important in evaluating and selecting metals for thread rolling, namely, rollability, flaking, and seaming. It reviews the capabilities and limitations of flat-die rolling, radial-infeed rolling, tangential rolling, through-feed rolling, planetary thread rolling, continuous rolling, and internal thread rolling, as well as the rolling machines and dies used. The article describes the factors affecting die life and provides information on radial die load, seam formation, surface finish, and thread dimensions that are affected by the form of the thread. It explains the reasons for using fluids in thread rolling. The article concludes with a comparison of rolling with cutting and grinding.

This article describes the presses that are mechanically or hydraulically powered and used for producing sheet, strip, and plate from sheet metal. It also presents the JIC standards for presses, compares the presses based on power source, details the selection criteria and provides information on the various drive systems and the auxiliary equipment. It describes the selection of die materials and lubricants for sheet metal forming and provides information on the lubrication mechanisms and selection with a list of lubricant types for forming of specific sheet materials of ferrous or nonferrous metals. The article reviews the various types of forming processes such as blanking, piercing, fine-edge blanking, press bending, press forming, forming by multiple-slide machines, deep drawing, stretch forming, spinning, rubber-pad forming, three-roll forming, contour roll forming, drop hammer forming, explosive forming, electromagnetic forming, and superplastic forming.

Bending is a common metalworking operation to create localized deformation in sheets (or blanks), plates, sections, tubes, and wires. This article emphasizes on the bending of sheet metal along with some coverage on flanging. It informs that variations in the bending stresses cause springback after bending, and discusses the variables and their effects on springback, as well as the methods to overcome or counteract them. These methods include overbending, bottoming or setting, and stretch bending. The article provides information on elastic bending, non-cylindrical bending, elastic-plastic bending, and pure plastic bending. Sheet metal bendability is a critical factor in many forming operations. The article illustrates the derivation of two relevant bend-ductility equations.

This article reviews the selection and formability characteristics of steels, with an emphasis on low-carbon steels and some coverage on the forming of high-carbon steels. It describes the key factors that affect the formability of steels in terms of steelmaking practices, surface finishes, metal thicknesses, and alloying. The article explains the bending and forming operations with some examples. It also describes the formation of various shells, including doubly contoured shells, deep recessed shells, and deep circular shells.