Amin, A. K. M. Nurul and -, Kok and Mahmud, Md. Asif
(2011)
Relative performances of preheating, cryogenic cooling and hybrid turning of stainless steel AISI 304.
In:
Advanced Machining Towards Improved Machinability of Difficult-to-Cut Materials.
IIUM Press, Kuala Lumpur, Malaysia, pp. 49-56.
ISBN 9789674181758
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Abstract
Chatter is an unwanted phenomenon in machining due to its adverse effects on the product
quality, operation cost, machining accuracy, tool life, machine-tool bearings, and machine-tool
life. The term defines the self-excited violent dynamic motion between the cutting tool and work
piece [1]. During high speed machining of steel, large amount of energy is used in shearing
process and substantial energy is converted to heat. Heat generation becomes more intensified in
machining of high strength materials because the machining process requires more energy than
that in cutting a low strength material. The rapid escalation of temperature at the cutting zone is
the primary cause accountable for high diffusion wear rate leading to shorter tool life. High tool
wear rate leads to high degree of chatter and poor surface finish. It is therefore essential to design
effective cooling systems to bring down the temperature at the cutting zones. Cryogenic cooling
is being looked at as a potential replacement of conventional mineral oil based coolants because
the latter is being rejected on grounds on serious environmental and health problems that it
causes [2].Cryogenic cooling is the cooling approach to replace conventional coolant by
liquefied gas in machining process [3].The impact of cryogenic cooling on chip breaking and
tool wear intensity during end milling and turning has been investigated by various researchers
[3-7], but there has not been any study on the impact of cryogenic cooling on chip formation and
chatter.Tungsten-inert-gas (TIG) plasma heating could be used to replace Laser Beam heating
and high frequency heating since TIG plasma heating also offers high heating capacity and at the
same time the use of inert gas would be able to protect the work surface against oxidation during
machining. In this research the TIG or tungsten-arc welding machine would therefore be used as
an well controlled and precise heat source to preheat the uncut layer of the work material before
it enters into the shearing zone. The major advantages of the plasma preheating are increased
metal removal rates, results in no metallurgical damage to the work piece and increase in tool life
[8].Similarly there has been some works [9] on the influence of workpiece preheating using
induction heating on machinability of work materials and chatter during end milling operation,
the application of preheating technique in turning should be explored further to confirm its
effectiveness of different heating process. It was found that preheating resulted in substantial
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