Modern Manufacturing Technology by Ms. Shikha Kashyap

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Modern Manufacturing Technology

• Introduction
• Ms Shikha Kashyap Assistant
  Professor Dept of Mechanical Engineering
  The NorthCap University, Gurgaon

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Need For
Unconventional Machining Methods

• Last few decades have witnessed a rapid growth in
  the development of harder and difficult to
  machine metal and alloys.
• It has been realized that such materials are
  difficult to machine by conventional methods, and
  therefore their machining is not only costly but
  also results into poor surface finish and shorter
  tool life.
• To overcome these difficulties a number of Newer
  Machining Methods have been developed.
• Machining of intricate and complicated shapes,
  thin and fragile components and accurate and
  economical forming of very hard, high strength
  materials which are being extensively used in
  aerospace and nuclear industries, have forced the
  scientists, engineers and technologists to search
  for new techniques of machining which can readily
  provide an effective solution to these problems.
• As a result of research and development for the
  last fifty years or so, several new methods of
  machining have emerged which can be grouped under
  the name of

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• Unconventional machining methods, or
• Non-traditional machining methods, or
• Physical machining process, or
• New technologies, or
• Modern machining methods

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Characteristic features
of modern machining processes that
distinguish them from conventional
machining processes

• The following are the characteristic
  features of non-traditional machining processes
  when compared with traditional or conventional
  machining processes
• Material is removed from the work piece without
  mechanical contact (with work piece).
• In many processes, material removal rate is
  independent of the hardness of the work piece.
• Cutting forces are independent of the hardness of
  the work material.
• The tool material need not be harder than the
  work material.( In many cases, softer materials
  can be used as tool material)
• Almost any work material irrespective of its
  hardness and strength can be machined.

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• Generally tool wear is negligible hence tool
  wear is not a problem.
• No burr is left on the work piece.
• Generally no residual stresses are left on the
  surfaces machined.
• In most of the cases entire shape can be obtained
  in one stage or in one setting. This is possible
  since material removal takes place uniformly over
  the entire area below the tool simultaneously.
• In majority of cases surface integrity" (Surface
  integrity is the surface condition of a work
  piece after being modified by a process.) of the
  surfaces produced by modern machining methods is
  superior.
• Modern machining methods can be integrated easily
  with micro-processors and numeric controls for
  better control of the processes and for improving
  the versatility and productivity of the machines.
• Intricately shaped contours and fine machining of
  precision holes are possible.

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Basic Principle of New Machining Methods

• The basic principle of machining by these new
  methods is to apply some form of energy to the
  work piece directly without almost any physical
  contact between the tool and the work piece and
  have the desired shape by material removal from
  the work piece.
• Different forms of energy applied to the work
  piece are
• 1) Mechanical Energy
• 2) Electrical (Electro-chemical energy)
• 3) Thermal Energy
• 4) Chemical Energy

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The actual mechanism or mode of metal removal for
different processes are given below

• Machining Process
• Conventional Machining Process (e.g. turning,
  milling, drilling)
• Abrasive jet machining (AJM)
• Ultrasonic Machining
• Chemical Machining

• Predominant Mechanism of Metal Removal
• Shear failure of work material
• Erosion of work material.
• Erosion of work material.
• Cavitation phenomenon.
• 4. Etching

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Conti

1. Electrochemical Machining
2. Electrochemical Grinding
3. Spark Erosion Machining
4. Electron beam machining
5. Laser beam machining
6. Ion beam machining
7. Plasma Arc Machining

1. Ion Displacement
2. Ion Displacement, Erosion of work material (due
   to grinding action of abrasive wheel)
3. Vaporization of work metal
4. Vaporization of work metal
5. Vaporization of work metal
6. Vaporization of work metal
7. Fusion of work metal

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Advantages of Non-traditional

• Material removed without mechanical contact with
  the work piece. (ECM, EDM,LBM,CHM)
• Material removal rate is independent of work
  piece hardness. (ECM, EDM,LBM)
• Cutting forces are independent of work piece
  hardness. (ECM, EDM,LBM,CHM)
• Tool material need not be harder than work piece
  material. (ECM, EDM,LBM,CHM,USM)
• Tool wear is not a problem. (ECM, LBM,CHM)
• Ability to machine any material. (LBM)
• Burr-free machining. (ECM,EDM,CHM)
• Stress-free machining. (ECM, ECG, CHM)

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• Uniform material removal over the entire area
  below the tool surface simultaneously. (ECM,CHM)
• Superior surface integrity possible.
  (ECM,CHM,ECG)
• Intricately shaped, very hard and fragile
  materials can be machined. (USM)
• Finely focused micro-machining possible.
  (EDM,LBM,EBM)
• Easy compatibility with numeric control and
  computer controls. (EDM,LBM,EBM,ECM)

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Limitations of Non-traditional Machining Processes

• All modern machining processes
  are generally costly. Their specific power
  consumption(kW/cm3/min) is quite high. The
  following are some of the specific limitations of
  the non- traditional machining process
• Work piece and tool must be electrically
  conductive (EDM,ECM)
• Depth of hole drilled is limited. (LBM)
• Heat-affected zones (HAZ) produced are not
  desirable. (EDM,LBM,EBM)
• For this purpose the compatibility of the
  process with the metallurgical state of the work
  piece material can be studied before using a
  particular non-traditional machining process for
  production work.
• There may be taper in the sidewalls of holes or
  cavities (EDM,LBM)
• Most of these limitations can be overcome
  and controlled, that the advantages can be
  obtained with good product quality assurance.

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Classification of new machining methods

• The classification is done on the basis
  of the type of energy used I the working zone
  for material removal action. Four distinct type
  of energy used are
• Mechanical Energy
• Electrical Energy (Electro-chemical energy)
• Thermal Energy (Thermo- electric energy)
• Chemical Energy
• Mechanical Energy
• Conventional machining
• Abrasive Jet Machining (AJM)
• Water Jet machining (WJM)
• Ultrasonic machining (USM)

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Electrical Energy

• Electro-chemical machining
• Electro-chemical grinding
• Electro-chemical Deburring
• Electro-chemical Honing
• Thermal Energy
• Spark erosion machining or Electro-discharge
  machining (EDM)
• Electron-Beam machining (EBM)
• Ion-Beam machining
• Laser-Beam machining
• Plasma-Arc machining

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Chemical
Energy

• Chemical machining
• Electro-polishing
• Photo-chemical machining
• Abbreviations used for Unconventional Machining
  Methods
• USM - Ultrasonic machining
• ECM - Electro-chemical machining
• AJM - Abrasive Jet Machining
• EDM - Electro-discharge machining
• LBM - Laser-Beam machining
• EBM Electron-Beam machining
• PAM Plasma-Arc machining
• ECG Electrochemical grinding

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Thank you