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Advanced Forming . Sheet metal operations not performed on presses. Apiwat Muttamara. Roll Forming. Figure 16.26 Schematic illustration of the roll-forming process. Stretch Forming. - PowerPoint PPT Presentation

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Advanced Forming Sheet metal operations not performed on presses

Apiwat MuttamaraKalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 16-#Roll Forming

Figure 16.26 Schematic illustration of the roll-forming process.Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 16-#2Stretch Forming

Figure 16.30 Schematic illustration of a stretch-forming process. Aluminum skins for aircraft can be made by this method. Source: Cyril Bath Co.Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 16-#3Tube BendingFigure 16.27 Methods of bending tubes. Internal mandrels, or the filling of tubes with particulate materials such as sand, are often necessary to prevent collapse of the tubes during bending. Solid rods and structural shapes can also be bent by these techniques.

Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 16-#4Manufacturing of Bellows

Figure 16.29 Steps in manufacturing a bellows.Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 16-#5Bulging

Figure 16.28 (a) The bulging of a tubular part with a flexible plug. Water pitchers can be made by this method. (b) Production of fittings for plumbing, by expanding tubular blanks under internal pressure. The bottomof the piece is then punched out to produce a "T." Source: J. A. Schey, Introduction to Manufacturing Processes (2d ed.)Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 16-#6Rubber Forming Process

Figure 16.39 a) The ram descends, the rubber gradually surrounds the sheet.The form block can be made of wood plastic or other materials that are easy to shape.Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 16-#Hydroform Process

Figure 16.39 The hydroform (or fluid forming) process. Note that, in contrast to the ordinary deep-drawing process, the pressure in the dome forces the cup walls against the punch. The cup travels with the punch; in this way, deep drawability is improved.Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 16-#8Conventional SpinningFigure 16.40 (a) Schematic illustration of the conventional spinning process. (b) Types of parts conventionally spun. All parts are axisymmetric.

Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 16-#9Shear and Tube Spinning

Figure 16.41

(a) Schematic illustration of the shear spinning process for making conical parts. The mandrel can be shaped so that curvilinear parts can be spun.

(b) Schematic illustration of the tube spinning process.Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 16-#10Explosive Forming

Figure 16.44 (a) Schematic illustration of the explosive forming process. (b) Illustration of the confined method of explosive bulging of tubes.Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 16-#11Magnetic-Pulse FormingFigure 16.45 (a) Schematic illustration of the magnetic-pulse forming process used to form a tube over a plug. (b) Aluminum tube collapsed over a hexagonal plug by the magnetic-pulse forming process.

(a)

(b)Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 16-#12Cost Comparison for Spinning and Deep Drawing

Figure 16.48 Cost comparison for manufacturing a round sheet-metal container either by conventional spinning or by deep drawing. Note that for small quantities, spinning is more economical.Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 16-#13Laser Welding

Production of an outer side panel of a car body, by laser butt-welding and stamping. Source: After M. Geiger and T. Nakagawa.Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 16-#14Characteristics of Sheet-Metal Forming Processes

Kalpakjian SchmidManufacturing Engineering and Technology 2001 Prentice-HallPage 16-#15TABLE 16.1

ProcessCharacteristics

Roll forming Long parts with constant complex cross-sections; good surface finish; high production rates; high tooling costs.

Stretch forming Large parts with shallow contours; suitable for low-quantity production; high labor costs; tooling and equipment costs depend on part size.

Drawing Shallow or deep parts with relatively simple shapes; high production rates; high tooling and equipment costs.

Stamping Includes a variety of operations, such as punching, blanking, embossing, bending, flanging, and coining; simple or complex shapes formed at high production rates; tooling and equipment costs can be high, but labor cost is low.

Rubber forming Drawing and embossing of simple or complex shapes; sheet surface protected by rubber membranes; flexibility of operation; low tooling costs.

Spinning Small or large axisymmetric parts; good surface finish; low tooling costs, but labor costs can be high unless operations are automated.

Superplastic formingComplex shapes, fine detail and close tolerances; forming times are long, hence production rates are low; parts not suitable for high-temperature use.

Peen forming Shallow contours on large sheets; flexibility of operation; equipment costs can be high; process is also used for straightening parts.

Explosive forming Very large sheets with relatively complex shapes, although usually axisymmetric; low tooling costs, but high labor cost; suitable for low-quantity production; long cycle times.

Magnetic-pulse forming Shallow forming, bulging, and embossing operations on relatively low-strength sheets; most suitable for tubular shapes; high production rates; requires special tooling.