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Machine Tools and Machining

ME 210 (3-0-0-3)

Vikrant Sharma

Assistant Professor

Mechanical Engineering DepartmentFET, MITS

vsharma.et@mitsuniversity.ac.in 

9887342424

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Course Objective

Understanding the basic parameters in the metal cutting operation.

Different types of chips formed in metal cutting.

Select cutting tool material for metal cutting.

Understand tool wear and tool life.

Determine cutting forces.

Understand classification of various machine tools.

Understand different components of the machine tools and theirfunctions.

Identify various methods used to generate different types of surfaces.

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Books

Rao P N, “Manufacturing Technology” 

Lindberg Roy, “Processes and materials of manufacturing” 

Ostwald Phillip, “ Manufacturing Processes and Systems” 

Chapman, “Workshop Technology” 

DeGarmo, “Materials and Processes in Manufacturing” 

Kalpakjian, “Manufacturing Engineering & Technology” 

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Manufacturing:

Manufacturing is an industrial activity that changes

the form of raw materials to create product.

Manufacture is derived from the Latin, manu factus,means “made by hand”.

Manufacturing is value addition processes. It isprocess of conversion of low utility and low value into aproduct of high utility and more value of required shape,

size and dimension.

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Lump of

iron /steel(Raw Material)

Product

Processes

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Manufacturing is science & technology for producing objects

Effectively

Efficiently

Economically

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This can be achieved through

Proper selection & application of existing processes &systems.

Proper selection & use of materials, tools, machine,environment etc.

Improvement of existing material & processes

Development of new material, processes, machine,technology etc.

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raw finished

material product

Conversion Process

Selection of optimum process is based on some objective

  manufacturing time

  production rate

  manufacturing cost

  profit

  profit rate

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Classification of manufacturing processes

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Machining :

Machining is an essential process of finishing by which jobs of

desired dimensions and surface finish are produce bygradually removing the excess material from the preformedblank in the form of chips with the help of cutting toolsmove past the work surface.

Machine Tool :

A machine tool is a non portable power operating device orsystem of devices in which energy is expanded to produce

 job of desired size by gradually removing the excess material

from the preformed blank in the form of chips with the helpof cutting tools move past the work surface.

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Major functional component of machine tools:

Device for holding job and tools Drive(s) for providing power and motions

Kinematics system(s) to transmit motion

Automation and control system

Structure/body

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Machining is a process of gradual removal of excess material

from the preformed blanks in the form of chips.

The form of the chips is an important index of machiningbecause it directly or indirectly indicates :

Nature and behavior of the work material under machining

condition Specific energy requirement (amount of energy required to

remove unit volume of work material) in machining work.

Nature and degree of interaction at the chip-tool interfaces.

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 Mechanism of chip formation

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Chip formation

There are three types of chips that are commonly

produced in cutting,

Œdiscontinuous chips

•continuous chips

Žcontinuous chips with built up edge

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Discontinuous chips :

When relatively brittle materials (e.g., cast irons) aremachined at low cutting speeds, the chips often form into

separate segments.

This tends to impart an irregular texture to the machinedsurface. High tool – chip friction and large feed and depth ofcut promote the formation of this chip type.

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Continuous chips : 

When ductile work materials are cut at high speeds and

relatively small feeds and depths, long continuous chips areformed.

A good surface finish typically results when this chip type isformed. A sharp cutting edge on the tool and low tool – chip

friction encourage the formation of continuous chips. Long, continuous chips (as in turning) can cause problems

with regard to chip disposal and/or tangling about the tool.To solve these problems, turning tools are often equippedwith chip breakers

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Continuous chips with built up edge (BUE) :

When machining ductile materials at low-to medium cutting

speeds, friction between tool and chip tends to causeportions of the work material to adhere to the rake face ofthe tool near the cutting edge. This formation is called abuilt-up edge (BUE)

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