This document discusses sheet metal processes and operations. Sheet metal is metal formed into thin, flat pieces that can be cut and bent into various shapes. Common materials for sheet metal include steel, aluminum, copper, and other metals. Key sheet metal operations covered include shearing, blanking/punching, bending, drawing, deep drawing, stamping, and others. Factors that influence these operations such as punch and die design, clearance, and lubrication are also addressed.

1. MANUFACTURING
TECHNOLOGY – I
CRAFTED BY:
RAMESH KUMAR A
Assistant Professor
Sona College of Technology
Salem
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2. SHEET METAL PROCESSES
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3. SHEET METAL PROCESSES
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 Sheet metal is metal formed by an
industrial process into thin, flat
pieces
 It is one of the fundamental forms
used in metalworking and it can be
cut and bent into a variety of
shapes
 Countless everyday objects are
fabricated from sheet metal
 Thicknesses can vary significantly;
extremely thin thicknesses are
considered foil or leaf, and pieces
thicker than 6 mm (0.25 in) are
considered plate
 Sheet metal materials:
 Galvanized iron
 Copper and its alloys
 Aluminium and its alloys
 Stainless steel
 Brass
 Bronzes
 Lead
 Tin
 Zinc

4. SHEET METAL CHARACTERISTICS
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5. SHEET METAL CHARACTERISTICS
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 ELONGATION:
 Determines the capability of the
sheet metal to stretch without
necking and failure
 Yield-Point elongation:
 Luder’s band and stretcher
strains causes flame like
depression on the sheet metal
surface
 Al-Mg alloys

6. SHEET METAL CHARACTERISTICS…
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 Anisotropy (planar):
 Exhibits different behavior in
different planar directions
 Anisotropy (normal):
 Determines thinning behavior of
sheet metals during stretching
 Grain size:
 Determines surface roughness
on stretched sheet metal
 Coarser the grain, the rougher
the appearance (orange peel)

7. SHEET METAL CHARACTERISTICS…
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 Residual stresses:
 Caused by non uniform
deformation during forming; causes
part distortion when sectioned and
can lead to stress-corrosion;
reduced for eliminated by stress
relieving
 Surface condition of sheet:
 Depends on rolling practice;
important in sheet forming as it
can cause tearing and poor surface
quality

8. SHEET METAL OPERATION
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 Shearing
 Bending
 Drawing
 Deep drawing
 Blanking
 Punching (Piercing)
 Stamping
 Embossing
 Spinning
 Roll forming

9. SHEARING
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10. SHEARING
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 Several cutting processes exist that
utilize shearing force to cut sheet
metal
 However, the term "shearing" by itself
refers to a specific cutting process
that produces straight line cuts to
separate a piece of sheet metal
 Most commonly, shearing is used to
cut a sheet parallel to an existing edge
which is held square, but angled cuts
can be made as well

11. FACTORS AFFECTING SHEARING OPERATION
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 Shape and material of punch
 Die, speed of punching, lubrication
 Clearance between punch and die

12. STAGES IN SHEARING
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Just before the
punch contacts
work
Punch begins to push
into work, causing
plastic deformation
punch compresses
and penetrates
into work causing
a smooth cut
surface
Fracture is initiated at
the opposing cutting
edges which separates
the sheet

13. SHEARING OPERATIONS
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14. BLANKING AND PUNCHING
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 Blanking - sheet metal
cutting to separate
piece (called a blank)
from surrounding stock
 Punching - similar to
blanking except cut
piece is scrap, called a
slug

15. PUNCHING AND PEARCING
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16. SLOTTING
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 A punching operation that forms
rectangular holes in the sheet.

17. PERFORATING
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 Punching a close arrangement of a
large number of holes in a single
operation

18. NOTCHING
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 Punching the edge of a sheet,
forming a notch in the shape of a
portion of the punch

19. NIBBLING
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 Punching a series of small
overlapping slits or holes along a
path to cut out a larger contoured
shape
 This eliminates the need for a
custom punch and die but will
require secondary operations to
improve the accuracy and finish of
the feature

20. LANCING
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 Creating a partial cut in the sheet,
so that no material is removed.
 The material is left attached to be
bent and form a shape, such as a
tab, vent, or louver

21. SLITTING
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 Cutting straight lines in the sheet
 No scrap material is produced

22. PARTING
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 Separating a part from the
remaining sheet, by punching away
the material between parts

23. CUTOFF
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 Separating a part from the
remaining sheet, without producing
any scrap
 The punch will produce a cut line
that may be straight, angled, or
curved

24. TRIMMING
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 Punching away excess material
from the perimeter of a part, such
as trimming the flange from a
drawn cup

25. SHAVING
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 Shearing away minimal material
from the edges of a feature or part,
using a small die clearance
 Used to improve accuracy or finish

26. THANK YOU!!!
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