METAL FORMING PROCESSES

1. SHEET METAL PROCESSES
Sheet metal characteristics - Typical shearing operations, bending and
drawing operations – Stretch forming operations –– Formability of sheet
metal – Test methods – Working principle and application of special
forming processes - Hydro forming – Rubber pad forming – Metal
spinning – Introduction to Explosive forming, Magnetic pulse forming,
Peen forming, Super plastic forming.

2. Introduction
 The working of metal thickness from 3mm to 5mm
with hand tools and simple machines into various
forms is known as sheet metal work.
Sheet metals
 Black iron
 Galvanized iron
 Stainless steel
 Brass
 Copper
 Zinc , Aluminium, tin plate and lead.

3. SHEET METAL CHARACTERISTICS
-Roll Forming
-Stretch Forming
-Drawing
-Stamping
-Rubber Forming
-Spinning
-Super Plastic Forming
-Peen Forming
-Explosive Forming
-Magnetic Pulse Forming

4. Classification of sheet metal
operation
 Shearing
1. punching
2. blanking
3. perforating
4. parting
5. notching
6.lancing
 Forming-bending, stretching, drawing, roll forming
 Finishing process.

5. PRESSES

6. Properties of sheet metal:
 Strength- tensile strength, shear strength, compressive
strength
 Elongation
 Elasticity
 Modulus of elasticity
 Ductility
 Plasticity
 Hardness
 Corrosive resistance.

7. Mechanically Operated Power Press
or OBI Press

8. Inclined Press

9. Inclinable Presss

10. Types of Cutting Dies
1.Progressive Dies

11. Compound Dies

12. Blanking

13. Piercing

14. CUTTING OPERATIONS

15. Blanking
 Blanking is the operation of cutting a flat shape from
the sheet metal
Piercing or punching:
* It is the operation of producing the hole on the work
piece by a punch

16. PHASES IN SHEARING

18. SHEARING OPERATION - BENDING
TYPES OF BENDING OPERATION
- Angle Bending

19. - Angle Bending
- Roll Bending

20. - Roll Forming
If the edges are formed to a desired shape in the form of bend is
made on the sheet metal
- Seaming
The process of providing lock between the two edges of the
different work metal.
SHEARING OPERATION - DRAWING
- Deep Drawing
Length of the part drawn is deeper then width.
- Box Drawing
Length of the part drawn is lesser then width

21. STRETCH FORMING OPERATION
Stretching is the process of stressing the work blank beyond its elastic limit
by moving a form block towards the blank.
FORM BLOCK METHOD

22. FORM BLOCK METHOD
MATING DIE METHOD

23. SPECIAL FORMING PROCESSES
1.0 HYDRO FORMING
1.Hydro Forming
2. Rubber Pad Forming
3. Metal Spinning
4. Explosive forming
5.Magnetic pulse forming
6. Peen forming
7. Super plastic forming
a) Hydro Mechanical forming
b) Electro Hydraulic Forming

24. YoucaN

25. 1) Hydro mechanical Forming

26. b) Electro Hydraulic Forming

27. 2.0 RUBBER PAD FORMING

28. RUBBER HYDROFORMING PROCESS

29. YoucaN

30. 3.0 METAL SPINNING
a) Manual Spinning
b) Power Spinning
Applications: Ash trays, flower pots, lamp shades, missile and radar units

31. 4).EXPLOSIVE FORMING PROCESSES
- Stand off operations
The explosive charge is located at some distance away from the blank
and energy is transmitted through some fluid medium such as water.
- Contact Operations
The explosive charge is directly located over the blank.
AEROSPACE COMPONENTS

32. Electro magnetic forming
 The energy stored in a capacitor bank is discharged
rapidly through a magnetic coil.
 EX: a ring shaped coil is placed over a tubular
workpiece.
 Depends upon the shape of the die the tube will
deform when the magnetic force pushes the metal.
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33. 5.0 MAGNETIC PULSE FORMING PROCESS

34. YoucaN

35. 6.0 PEEN FORMING PROCESS

36.  In this process, a stream of balls or metals shots is
blasted against the surface of the sheet metal blank to
be made into the required shape.
 The part to be made by the sheet metal placed on a
form block or it may be suspended from support.

37. 7.0 SUPER PLASTIC FORMING PROCESS
a) Loading
b) Forming
c) Forming
d) Release

38. This method involves in hot forming upto 1000 c
superplastic alloys using an inert gas pressure upto
50bar.
Advantage:
 One step process
 Minimizes amount of scrap
 Higher material elongation possible
Application:
 Forming of– automotive body panels, aircraft frames

39. BASIC SHEARING OPERATION
1.0 Cutting operations
(a) Blanking

40. BASIC SHEARING OPERATION
1.0 Cutting operations

41. BASIC SHEARING OPERATION
1.0 Cutting operations

42. BASIC SHEARING OPERATION
2.0 Forming operations
(a) Bending
(b) Drawing
(c) Sequeezing
(d) Embossing
(e) Nibbling
It is an operation of cutting any shape from sheet metal
without special tools. It is done on a nibbling machine.

43. FORMABILITY OF SHEETMETAL
Formability = f(f1, f2)
F1 = Material Variables - ductility
F2 = Process Variables – stress system, lubrication, die design etc
Law 1 – Process of fracturing
Ductility of the same material is lower if the section size is large.
Law 2 –Law of geometrical Similitude
1 Blank are geometrically similar to dimension, thickness, width etc.
2 Unit strain at corresponding locations are identical
3 Forces required directly proportional to the square of the thickness
.
4 Consumption of work proportional to the cube of its thickness.

44. FORMABILITY TEST METHOD
1 Formability tests for bulk deformation
Elastic deformation and Plastic deformation
2 Formability test for elastic plastic deformation
1) Tensile test
a) Stretch forming - local thinning
b) Drawing operation – Lower punch by thinning under bi-axial stresses.
2) Simulative tests
a)Erichsen test – Stretchability based on erichsen number
b)Olsen test
c) Swift test - based on blank to punch diameter- drawing ratio
d) Fukui test – both assessed - based on formability index

45.  Erichsen test:
standard specimen of 90mm wide is rigidly clamped
against a die having 27mm diameter opening. A special
punch of 20mm diameter is moved against the sheet
metal. The movement of the punch is continued until
the fracture starts.
Olsen test:
Die opening size of 50mm diameter

46. FORMABILITY TEST METHOD
3) Full scale forming test