Processing Metals
Wasting Process
Processing Of Metals
• I Wasting: materials is cut away
»
»
»
»
Sawing & Filing
Drilling & Milling
Grinding & sanding
Blanking & Piercing
• 2- Addition - Materials are joined together
» Bolts & Screws
» Welding, Brazing, Soldering
» Adhesives- Epoxy Resin
3-Redistribution
• Material are reshaped WITHOUT loss of
material
Gravity
• Casting- Sand casting & Die Casting
• Forging- Cold & Hot
• Forming
Press Forming
» Embossing & Coining
»
• Sintering
Low Pressure
High Pressure
Blanking & Piercing
Keywords
• Sheet Metals
• Shearing- Separating material into two
parts
• Guillotine
• Piercing- Removing material as scrap
• Blanking-Removing material to use for
parts
• ‘Blank’
Examples
Piercing and Blanking
•
Piercing and blanking are essentially the same process, involving the stamping of
shapes out of sheet metal or metal strip. The differences in the process simply
depend on which bit of metal is to be kept: in piercing a shaped hole is made in the
metal, whereas in blanking a shape is stamped out of the metal and then used.
The Process
Piercing
punch
strip
die
The punch and die are shown here
in the closed position. Notice how
the punch fits into the die but does
not enter it, stopping instead as
soon as the metal has been cut.
Accurate alignment of the two is
essential.
Blanking
Blanking
Punch
Ram
Stripper
Metal Strip
Die
Bolster plate
The main components used for blanking in
mass production are a punch, a die and a
stripper plate. The stripper plate prevents
the metal ‘riding up’ the die on its upward
travel. The die is attached to the main press
by means of a bolster plate. The punch is
attached to a movable ram.
Blank falling through die
and bolster plate
Progressive Piercing and Blanking
Progressive Piercing and Blanking
Ram
Blanking
punch
Piercing punch
Pilot
Scrap
Stripper
Metal Strip
Stop
Die
Many products requires to be both pierced and
blanked. This is often done in the same press by
first piercing the metal, and then moving it along
to another die and blanking out the desired
shape. This process is called progressive
piercing and blanking.
1 The metal strip is fed into the first die.
2 A hole is pierced in the metal on the first stroke
of the ram.
3 The ram rises and metal is moved into position
over the blanking die.
Finished Washer
Metal Strip
4 Accurate alignment is essential here.
5 The punch descends and the completed
component ( in this case a washer) is blanked
from the metal strip. At the same time a hole is
pierced in the next washer.
6 Piercing is normally done before blanking, as
this minimises the risk of fracturing the metal.
Piercing and Blanking
•
Materials
Most types of metals can be pierced and blanked in sheet or strip form. The metal is
normally annealed first so as to minimise the risk of fracture or tearing.
•
Identifying Features
A sheared surface will show two distinct areas of deformation and fracture. With the
correct clearance angles in the punch, this can be minimised to give a reasonably smooth
edge which will require no further finishing.
•
Uses
Uses of piercing and blanking include component parts for a variety of tool and products.
Often products made from sheet metal that have been press formed are pierced to give a
decorative finish.
Homework- Revision Notes
• Explain Blanking and Piercing Process with
annotated Diagrams.
• The stainless steel saucepan is made by blanking
and spinning. Use notes and diagrams to explain
these processes
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References:
fdp.nu/mikelldevice/spinning.pdf
www.metal-spinners.com/faqs.html
fdp.nu/mikelldevice/spinning.pdf
http://www.metal-spinners.com/faqs.html