1.Final Product (Production
process)
There is no previous entry about Final Product.
New answer:
Final
products made by the industries listed in Table 2.3 can be divided into two
major classes: consumer goods and capital goods. Consumer goods are products
purchased directly by consumers, such as cars, persona! computers, TVs, tires,
toys, and tennis rackets. Capital goods are products purchased by other
companies to produce goods and supply services. Examples of capital goods
include commercial aircraft, mainframe computers, machine tools, railroad
equipment, and construction machinery.
In
addition to final products, which are usually assembled, there are companies in
industry whose business is primarily to produce materials, components, and
supplies for the companies that make the final products. Examples of these
items include sheet steel, bar stock, metal stampings, machined parts, plastic
moldings and extrusions, cutting tools, dies, molds, and lubricants. Thus, the
manufacturing industries consist of a complex infrastructure with various
categories and layers of intermediate suppliers that the final consumer never
deals with.
(Groover,
M. P., Automation,Production Systems and
CIM, p.31)
2.Nitriding
Previous
answer:
Nitriding is a treatment in which nitrogen is diffused
into the surfaces of special alloy steels to produce a thin hard casing without
quenching.To be most effective, the steel must contain certain alloying
ingredients such as aluminum(0,85-1,5%) or chromium(5% or more).These elements
form nitride compounds that precipiate as very fine particles in the casing to
harden the steel.
(M.Groover. Fundamental of Modern Manufacturing, page
654)
New
answer: (better)
nitriding - consists of heating the workpiece in an
atmosphere of ammonia or other gas containing nitrogen. The process is limited
to alloy steels that have the capability of absorbing nitrogen. Upon prolonged
heating (20 to 100 hrs) at temperatures from 925 to 1050°F (500 to
565"C)(below the transformation range), the workpiece absorbs nitrogen from
the gas and forms nitrides which provide the necessary hardness. Special steels
have been developed to facilitate nitriding. Quenching is not required.
Hardenable steels to be nitrided are first hardened and
tempered. Normalizing may also precede the nitriding operation if workpiece
sections are large. Decarburized material must be removed before nitriding and
thorough workpiece cleaning is also important before the operation. Nitriding
produces very hard cases and little workpiece distortion. Case hardened depths
typically range from 0.008 to 0.30 in (0.20 to 7.5 mm). This process also provides
improved wear and corrosion resistance and lessened possibility of galling or
fatigue failure.
(Bralla, J. G., Handbook
of Manufacturing Processes ,How Products, Components and Materials Are Made,
p.351)
3.Carburizing (Manufacturing
method - treatment)
Previous
answer:
Carburizing
is the most common surface-hardening treatment.It involves heating a part of
low carbon steel in the presence of a carbon-rich environment so that C is
diffused into the surface.In efect the surface is converted to a high carbon
steel, capable of higher hardness than the law-C core.The carbon-rich
environment can be created in several ways.One method involves the use of
carbonaceous materials such as charcol or coke packed in a closed container
with the parts.
(M.Groover.
Fundamental of Modern Manufacturing, page 654)
New
answer: (better)
G3b1.
carburizing - is the oldest case hardening method, commonly applied to
lowcarbon steel workpieces. They are heated to above the transformation
temperature range while in contact with a carbon-containing material in
gaseous, liquid, or solid form. The carbon is absorbed by the workpiece
material and the outer surface thus becomes high-carbon steel. Workpieces are
then either quenched or slowly cooled and further heat treated, depending on
the application and the initial grade of steel. The depth of the case depends
on the time and temperature of the carbon absorption operation. The three
approaches are illustrated in Fig. 8G3bl.
(Bralla, J. G., Handbook
of Manufacturing Processes ,How Products, Components and Materials Are Made,
pp.349-350)
4.Extrusion (Manufacturing
method)
Previous
answer:
Extrusion operations are similar to plastic injection
except that the product is continuous rather than discrete.The starting
material and the methods for loading into the extrusion machine are basically
the same as for injection molding.A pliable product can be collected in a coil,
while a rigid one is usually cut the standard lengths.Either method can be
automated to allow unattended operation of extrusion machines.
(Automation, production systems,and computer
integrated manufacturing 3.edition ,Mikell P.Groover, p.385)
New
answer: (better)
Extrusion is one of the fundamental shaping processes,
for metals and ceramics as well as polymers. Extrusion is a compression process
in which material is forced to flow through a die orifice to provide long
continuous product whose cross-sectional shape is determined by the shape of
the orifice. As a polymer shaping process, it is widely used for thermoplastics
and elastomers (but rarely for thermosets) tomass produce items such as tubing,
pipes, hose, structural shapes (such as window and doormolding), sheet and
film, continuous filaments, and coated electrical wire and cable. For these
types of products, extrusion is carried out as a continuous process; the
extrudate (extruded product) is subsequently cut into desired lengths. This
section covers the basic extrusion process, and several subsequent sections examine
processes based on extrusion.
(Groover, M. P., Fundamentals
Modern Manufacturing 4th edition, pp. 271-272)
5.Close Die Forging
Previous answer:
In
closed or impression die forging, the starting forging stock is invariably a
billet or bloom, since the weight and dimensions are usually critically. Upper
and lower dies are contoured or sunk to form the required shape when the billet
is inserted between them. The forging force may be supplied instantaneously,
when the dies are closed over the billet, or more gradually when a hydraulic
press is used. High forging pressures are required to make the material flow to
fill the dies, and for even modestly sized forging such as automotive
crankshafts, hydraulic or large mechanical presses are used. Since appreciable
costs are involved in providing the dies, close die forging is more applicable
to large production runs.
(Edward
G. Nisbett, Steel Forgings: Design, Production, Selection, Testing, and
Application,ASTM International,2009,p,25 )
New answer: (better)
Impression-die
forging, sometimes called closed-die forging, is performed with dies that contain
the inverse of the desired shape of the part. The process is illustrated in a
three-step sequence in Figure 19.14.The rawworkpiece is shownas a cylindrical
part similar to that used in the previous open-die operation. As the die closes
to its final position, flash is formed by metal that flowsbeyond the die cavity
and into thesmall gap between the die plates.Although this flash must be cut
away from the part in a subsequent trimming operation, it actually serves an
important function during impression-die forging. As the flash begins to formin
the die gap, friction resists continued flow ofmetal into the gap, thus
constraining the bulk of the work material to remain in the die cavity. In hot
forging, metal flow is further restricted because the thin flash cools quickly
against the die plates, thereby increasing its resistance to deformation.
Restrictingmetal flow in the gap causes the compression pressures on the part to
increase significantly, thus forcing the material to fill the sometimes
intricate details of the die cavity to ensure a high-quality product.
(Groover, M. P., Fundamentals
Modern Manufacturing 4th edition, pp. 409-410)
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