THIS IS A COURSE ONMANUFACTURING …WHAT IS THE DIFFERENCE BETWEEN:˃ SCIENCE˃ TECHNOLOGY˃ ENGINEERING
HOW MANY OF YOU HAVEA BI-CYCLE ??ANDHOW MANY OF YOU HAVEOPENED IT ??
The Ten Fundamental Laws of Engineering1) The correct order is: debug, then ship. TRUE2) If it isnt broken, dont fix it. FIDDLE WITH IT3) If you fiddle with something long enough, it will break. LET IT BREAK !4) It works if you plug it in. TRUE5) A working example is worth a thousand manual pages. VERY TRUE !!6) Failures occur where two parts join. TRUE7) Demos cause failures. TRUE8) Systems grow more complex with time. TRUE9) If its too complex, rebuild it. YES10) Small parts vanish when dropped. TRUETHERE IS NO FAILURE IN RESEARCH . . . NEXT >>
POWDER METALLURGY. . . is a forming techniqueEssentially, Powder Metallurgy is an art & science of producing metal or metallic powders, and using them to make finished or semi-finished products.
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 . . .
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
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.
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.)
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.
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.
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
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 <<
P/M Merits :o The main constituent need not be meltedo 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 propertyo Near Nett Shape is possible, thereby reducing the post- production costs, therefore, • Precision parts can be producedo 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
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
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.
on March 01, 2011POWDER 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.