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Metal Forming Operations

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Presentation on theme: "Metal Forming Operations"— Presentation transcript:

1 Metal Forming Operations
Rolling: makes sheet metal (hot or cold) Kalpakjian Forging: makes strong solid parts (hot or cold) Kalpakjian

2 makes complex cross-sections from soft metals and plastics (hot)
Extrusion: makes complex cross-sections from soft metals and plastics (hot) Kalpakjian Wire drawing: Makes strong small dia. wire (hot or cold) Kalpakjian

3 Bend sheet metal about single axis (hot or cold)
Bending: (2D) Bend sheet metal about single axis (hot or cold) Kalpakjian Deep drawing (3D) Makes “cups” from sheet metal, for mass production. (cold) Kalpakjian

4 Makes “cups” from sheet metal, for lower production. (cold)
Spinning: Makes “cups” from sheet metal, for lower production. (cold) Kalpakjian Roll forming (Hot): Moves bulk metal, makes I-beams Roll forming (Cold): Bends sheetmetal into complex cross-sections Kalpakjian Kalpakjian

5 Cut or punch sheetmetal (hot or cold)
Shearing: Cut or punch sheetmetal (hot or cold) Kalpakjian

6 Forming Oriented flowlines decrease fracture risk from grain boundaries, improve strength along flow direction. (Directional properties). Especially seen in: Forging Rolling Drawing ASM Metals Handbook Vol.9 Cracks tend to start where grain boundaries intersect surface. Forging minimizes these. Bralla

7 Thread-rolling for bolts:
Rolled threads stronger than machined (and less expensive) Kalpakjian

8 Directional Properties in Rolling
Oriented flowlines: Less ductility when bent in one direction More ductility when bent in the other Kalpakjian

9 Slab Production: Hot Rolling
Color & Temp

10 Progressive Hot Rolling: smaller, uniform grains
Kalpakjian

11 Hot Working: Forging Open Die Forging www.smeedwerkunica.nl
T.Green, WIT Paul Berenson,

12 Forging Presses Kalpakjian Erie Press Hydraulic press Mechanical press with an eccentric drive: faster Slow but high force and low cost

13 Forging Presses Knuckle-joint press Screw press Gravity drop hammer:
Simplest Kalpakjian

14 Forging: Closed Die Forging
Kalpakjian

15 Forging: Heat Loss Metal near die surfaces are coolest, flow less

16 Upset Forging (hot or cold)
Bolt manufacture Kalpakjian

17 Roll Forming (hot): I-beams Kalpakjian www.civil.ubc.ca
Lunchtime on a Crossbeam, Unknown,

18 Extrusion (hot or cold):
Typ.: Alum., soft metals With special lubes: steels ~Any cross-section Inexpensive dies Good finish en.wikipedia.org T.Green, WIT

19 Hollow cross-sections: Use Mandrels
Extrusion: Hollow cross-sections: Use Mandrels Kalpakjian

20 Mannesmann Process: Piercing
(Hot) Seamless pipe, tube Kalpakjian

21 Cold-Working (vs. Hot):
Products: Better tolerances Much better surface finish Elongated (and smaller) grains Turns inexpensive alloys into stronger but less ductile products Sheetmetal lends itself to cold working, not hot working Processes: Higher processing forces Larger and stronger machinery Less ductility available Lower energy use

22 Cold Rolling: Sheetmetal production
finance.pipex.com Kalpakjian

23 Cold Rolling: Sheetmetal production
Cluster rolls support smaller contacting rolls

24 Cold Rolling: Sheetmetal production
Residual Stresses may lead to warping after bar is machined Kalpakjian Large reduction Small reduction

25 Roll Forming of Sheetmetal (cold)
Kalpakjian

26 Roll Forming of sheetmetal

27 Punching & Blanking of Sheetmetal
Stripper plate Die T.Green, WIT Punching (Scrap) Blanking (Saved: a “blank”)

28 Punching of Sheetmetal
Kalpakjian

29 Blanking of Sheetmetal: Efficient Nesting of Blanks
Kalpakjian

30 Sheetmetal: Bending Springback: Kalpakjian

31 Sheetmetal: Minimum Bend Radius
Tight radius bends (folds) require metal with ~40% ductility Kalpakjian

32 Bending of Sheetmetal Use notches to avoid tearing and wrinkling in right-angle bends Kalpakjian

33 Bending of Sheetmetal Press Brakes: For lower production volumes
10-30 foot long tons

34 Bending: Press-Brake Operations Kalpakjian

35 Relative Unit Costs of a Small Connecting Rod
For large quantities, forging and die casting are more economical. Sand casting is the more economical process for fewer than about 20,000 pieces. Kalpakjian

36 Deep Drawing (cold, for sheetmetal)
- Punch draws blank into die Metal is supported on both sides to avoid wrinkling Hold-down pressure (blankholder force) is primary process variable if too high: tearing if too low: wrinkling Kalpakjian

37 Deep Drawing “Draw beads” may be used to control metal flow Kalpakjian

38 Spinning Ideal for Lower production volumes Large parts
Inexpensive tooling

39 Spinning videos

40 Cost comparison: manufacturing a round sheet-metal container by spinning and deep drawing.
For small quantities, spinning is more economical. Kalpakjian

41 Finite Element Simulations
Predict and minimize tearing and wrinkling locations nsmwww.eng.ohio-state.edu tmku209.ctw.utwente.nl

42 Progressive Stamping Dies
Common method to handle complex parts

43 Tube-drawing Seamless Thin wall, tight tolerance, strong
DOM: Drawn Over Mandrel Tubing Seamless Thin wall, tight tolerance, strong Malicky “Floating plug” Kalpakjian

44 Bicycles: Butted DOM tubing
Increased wall thickness at ends Reinforces high stress points materials.npl.co.uk

45 Diego Rivera, Detroit Industry, Detroit Institute of Art

46 References Kalpakjian: http://www.nd.edu/~manufact/index3.htm
Bralla: James G. Bralla, Design for Manufacturing Handbook, McGraw-Hill, 2nd Edition. In:


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