Page 457 - 04. Subyek Engineering Materials - Manufacturing, Engineering and Technology SI 6th Edition - Serope Kalpakjian, Stephen Schmid (2009)

Powder-Metal

Processing and 17

Equipment

l7.I Introduction 437
° This chapter describes the powder metallurgy process for producing net-shape l7.2 Production of Metal
parts from metal powders. Powders 438
l1.3 Compaction of Metal
° The chapter begins by examining methods of producing and blending of metal
Powders 444
powders and investigates the shapes that powders will develop based on the I1.4 Sintering 452
process employed to make them. l7.5 Secondary and Finishing
° A number of secondary operations are then presented, such as compaction to Operations 456
I1.6 Design
consolidate the powder into a desired shape, and Sintering to fuse the particles
Considerations 457
to achieve the required strength. |7.7 Process Capabilities 459
° Additional processes particular to powder metallurgy are then discussed, and l7.8 Economics of Powder
Metallurgy 460
design rules are presented.
EXAMPLES:
° The chapter ends with a discussion of process capabilities and economics com~
pared with other competing manufacturing operations. l1.l Hot lsostatic Pressing of a
Valve Lifter 449
I1.2 Mobile Phone
Typical products made: Connecting rods, piston rings, gears, cams, bushings, bear- Components Produced
ings, cutting tools, surgical implants, magnets, metal filters, and surgical implants. through Metal Injection
Molding 450
Alternative processes: Casting, forging, and machining.
CASE STUDY:
l7.I Powder Metallurgy Parts
l1.l Introduction in a Snowblower 46|

In the manufacturing processes described thus far, the raw materials used have
been metals and alloys either in a molten state (casting) or in solid form (metal-
working). This chapter describes the powder metallurgy (PM) process, in which
metal powders are compacted into desired and often complex shapes and sintered
(heated without melting) to form a solid piece. This process first was used by the
Egyptians in about 3000 B.C. to make iron tools. One of its first modern uses was
in the early 1900s to make the tungsten filaments for incandescent light bulbs.
The availability of a wide range of metal-powder compositions, the ability to
produce parts to net dimensions (net-shape forming), and the overall economics
of the operation give this unique process its numerous attractive and expanding
applications.
A wide range of parts and components are made by powder-metallurgy tech-
niques (Fig. 17.1): (a) balls for ballpoint pens; (b) automotive components (which

437

HAPTER C