CRYOGENIC COOLING DURING MACHINING - snsce.ac.in · PDF fileCutting fluids Cutting fluid is a...

CRYOGENIC COOLING

DURING MACHINING By

Dr.K.Senthil Kumar Associate Professor / Mechanical

TOPICS TO BE DISCUSSED

10/11/2017 RESEARCH SEMINAR / CRYOGENIC COOLING DURING

MACHINING / Dr.K.Senthil Kumar, ASP/Mech 2/40

Machining Process Need for Cooling Cryogenic Cooling Applications during machining

Production Process

Conversion of raw material into a finished product through sequence of operations

A product can be made from

Metal Forming processes Ex: Casting

Metal Joining processes Ex: Welding

Metal Removal processes Ex: Drilling


MACHINING / Dr.K.Senthil Kumar, ASP/Mech 3

Machining Process

Metal Removal process

Removal of material from a work piece to obtain required shape and size

Machining, as well as all Manufacturing operations is a system consisting of the work piece, the tool and the machine

10/11/2017

RESEARCH SEMINAR / CRYOGENIC COOLING DURING MACHINING / Dr.K.Senthil Kumar, ASP/Mech 4/40

Categories of Machining

Process

Cutting: Make use of single-point or multipoint cutting tools for metal removal, Ex : Turning, Drilling etc

Abrasive processes, such as Grinding.

Nontraditional Machining (NTM) or(UCM) : Processes which utilize Electrical, Chemical, and Optimal sources of energy Ex: EDM, ECM, AJM etc

10/11/2017

RESEARCH SEMINAR / CRYOGENIC COOLING DURING MACHINING / Dr.K.Senthil Kumar, ASP/Mech

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Heat generation during

Machining

Heat has critical influences on Machining.

It increase tool wear and thereby reduces tool life

Leads to Thermal deformation, Environmental problems, etc.

The properties of materials vary with the temperature – the mechanical process and the thermal dynamic process are inter-related



Cutting fluids

Cutting fluid is a type of coolant and lubricant designed specifically for metalworking processes, like machining.

There are various kinds of cutting fluids, which include oils, oil-water emulsions, pastes, gels, aerosols (mists), and air or other gases.

Depending on the type of application, it may be referred to as cutting fluid, cutting oil, cutting compound, coolant, or lubricant.



Properties of a

Cutting fluids

Maintain the work piece at a stable temperature (critical when working to close tolerances). Very warm is acceptable.

Maximize the life of the cutting tool by lubricating the working edge and reducing tool wear.

Ensure safety for the people handling it (toxicity, bacteria, fungi) and for the environment upon disposal.

Prevent rust on machine parts and cutters.



Cryogenic Cooling

Cryogenics is the study of the production and behaviour of materials at very low temperatures.

Scientists assume a gas to be cryogenic if it can be liquefied at or below −150 °C (123.15 K; −238.00 °F).

Common cryogenics are helium, hydrogen, neon, nitrogen, oxygen, argon, krypton, xenon, methane, ethane, and propane.



History of Cryogenic

During World War II, scientists found that metals frozen to low temperatures showed more resistance to wear

Ed Busch founded a cryogenic processing company in Detroit called CryoTech in 1966

He experimented the possibility of increasing the metal tools life to anywhere between 200%-400% using cryogenic tempering instead of heat treating



Common Applications

of Cryogenic

Certain rare blood groups are stored at low temperatures, such as −165 °C.

To cool super conductors in underground power transmission

Special cryogenic chemical reactors are used to remove reaction heat and provide a low temperature environment.

Cryogenic food freezing is helpful for large scale food processing industries.

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Common Applications

of Cryogenic

The freezing of foods and biotechnology products, like vaccines, statin drugs requires nitrogen freezing systems

Certain soft or elastic materials become hard and brittle at very low temperatures, which makes cryogenic milling (cryomilling)

Tupolev developed Tu-154, with a cryogenic fuel system which uses liquefied natural gas or LNG as fuel, and made its first flight in 1989.

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Liquid Nitrogen

• Nitrogen is a safe, non-combustible, and non-corrosive gas which accounts to 78% of air we breathe

• The normal melting and boiling point for nitrogen (at 100 Pa) are -210 and -196 °C

• Liquid nitrogen causes freezing cold environment, where delivered.

• It is colourless, odourless, tasteless, and inert fluid, and presents a potential liquefied gas that can be used during machining process.

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Liquid Nitrogen Production



Applications during

Machining

• Used for cooling the cutting tool and/or part during the machining process.

• Applied at the cutting zone which is exposed to the highest temperature during the machining process.

• When delivered at the cutting zone, it immediately evaporates and returns back to the atmosphere.

• It leave no residue to contaminate the part, chips, machine tool, or operator and eliminates disposal costs related to Coolant Lubricant Fluid usage. 10/11/2017


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Cryogenic Machining Setup



Potential benefits of

Cryogenic Machining Sustainable machining methods (cleaner, safer,

environment friendly, more health acceptable, etc.) to eliminate numerous costs associated with conventional cutting fluids and clean-up operations

Increase of material removal rate & cutting speeds without increases in worn tool and tool change over costs – increase of productivity

Increasing of tool life due to lower abrasion and chemical wear



Potential benefits of

Cryogenic Machining

Machining of hard parts and hard to machine alloys

Improvement of surface roughness of machined work piece

Quality improvement of produced parts by preventing mechanical and chemical degradation of machined surface

Improvement of manufacturing flexibility due to reduced production times and high output, etc.

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Cryogenic Machining Vs Coolant

Lubricant Fluid (CLF) Lower cutting temperatures in cutting zone

Improvement of chip breakability

Decreased BUE formation probability

Decreased of burr appearance probability

Inert environment assurance

No oil-based emulsion used

No additional processes needed

Safer Environment, Easy disposal.

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