2. THIS IS A COURSE ON
MANUFACTURING …
WHAT IS THE DIFFERENCE BETWEEN:
˃ SCIENCE
˃ TECHNOLOGY
˃ ENGINEERING
3. HOW MANY OF YOU HAVE
A BI-CYCLE ??
AND
HOW MANY OF YOU HAVE
OPENED IT ??
4. The Ten Fundamental Laws of Engineering
1) The correct order is: debug, then ship. TRUE
2) If it isn't broken, don't fix it. FIDDLE WITH IT
3) If you fiddle with something long enough, it will break. LET IT BREAK !
4) It works if you plug it in. TRUE
5) A working example is worth a thousand manual pages. VERY TRUE !!
6) Failures occur where two parts join. TRUE
7) Demos cause failures. TRUE
8) Systems grow more complex with time. TRUE
9) If it's too complex, rebuild it. YES
10) Small parts vanish when dropped. TRUE
THERE IS NO FAILURE IN RESEARCH . . . NEXT >>
5. POWDER METALLURGY
. . . is a forming technique
Essentially, Powder Metallurgy is an art & science of
producing metal or metallic powders, and
using them to make finished or semi-finished
products.
6. POWDER METALLURGY
. . . particulate technology is
probably the oldest forming
technique known to man
There are archeological evidences to prove that
the ancient man knew something about it . . .
7. History of P/M
IRON Metallurgy >
a) How did Man make iron in 3000BC?
b) Did he have furnaces to melt iron?
Quite unlikely, then how ???
i. Crushed iron ore with charcoal were heated
together in a furnace, with air blasts, and
ii. The reduced material, which would then be
spongy, [ DRI ], used to be hammered to a
solid or to a near solid mass.
Example: The IRON PILLER at Delhi
8. P/M
An important point that comes out :
The entire material need not be melted to fuse it.
The working temperature is well below the
melting point of the major constituent,
making it a very suitable method to work with refractory
materials, such as: W, Mo, Ta, Nb, oxides, carbides, etc.
It began with Platinum technology about 4 centuries
ago … in those days, Platinum, [mp = 1774°C], was
"refractory", and could not be melted.
9. History of P/M
Going further back in Time . . .
The art of pottery, (terracotta), was known to the
pre-historic man (Upper Palaeolithic period,
around 30,000 years ago)!
Dough for making bread is also a powder
material, bound together by water and the
inherent starch in it. Baked bread, in all its
variety, is perhaps one of the first few types of
processed food man ate.
(Roti is a form of bread.)
10. Renaissance of P/M
The modern renaissance of powder metallurgy
began in the early part of last century, when
technologists tried to replace the carbon filament in
the Edison lamp.
The commercially successful method was the one
developed by William Coolidge. He described it in
1910, and got a patent for it in 1913.
This method is still being used for manufacturing
filaments.
11. Renaissance of P/M
The Wars and the post-war era brought about huge
leaps in science, technology and engineering.
New methods of melting and casting were perfected,
thereby slowly changing the metallurgy of refractory
materials.
P/M techniques have thereafter been used only
when their special properties were needed.
12. P/M Applications
► Electrical Contact materials
► Heavy-duty Friction materials
► Self-Lubricating Porous bearings
► P/M filters
► Carbide, Alumina, Diamond cutting tools
► Structural parts
► P/M magnets
► Cermets
► and many more . . . such as Hi-Tech applications
13. Hi-Tech Applications of P/M
Anti-friction products
Friction products
Filters
Make-Break Electrical Contacts
Sliding Electrical Contacts
THESE COMPONENTS ARE USED
Very Hard Magnets IN AIR & SPACE CRAFTS, HEAVY
Very Soft Magnets MACHINERY, COMPUTERS,
Refractory Material Products AUTOMOBILES, etc…
Hard and Wear Resistant Tools
Ferrous & Non-ferrous Structural parts
Etc . . .
BACK <<
14. P/M Merits :
o The main constituent need not be melted
o The product is porous - [ note : the porosity can be controlled]
o Constituents that do not mix can be used to make composites,
each constituent retaining its individual property
o Near Nett Shape is possible, thereby reducing the post-
production costs,
therefore, • Precision parts can be produced
o The production can be fully automated,
therefore, • Mass production is possible
• Production rate is high
• Over-head costs are low
• Break even point is not too large
• Material loss is small
and • Control can be exercised at every stage
15. P/M Disadvantages :
o Porous !! Not always desired.
o Large components cannot be produced on a large
scale [Why?]
o Some shapes [such as?] are difficult to be produced
by the conventional p/m route.
WHATEVER, THE MERITS ARE SO MANY THAT P/M,
AS A FORMING TECHNIQUE, IS GAINING POPULARITY
16. P/M Summarizing :
Powder Metallurgy is sought when -
a) It is impossible to form the metal or material by any
other technique
b) When p/m gives unique properties which can be put
to good use
c) When the p/m route is economical
There may be over-lapping of these three points.
17. on March 01, 2011
POWDER METALLURGY
Powder Metallurgy is an art & science of
1. producing metal or metallic powders, and
2. using them to make finished or semi-finished
products.
