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Introduction to Manufacturing Technology (Overview of Manufacturing technologies)

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Introduction to Manufacturing Technology (Overview of Manufacturing technologies) Instructors: (1)Shantanu Bhattacharya, ME, IITK, email: bhattacs_at_iitk.ac.in – PowerPoint PPT presentation

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Title: Introduction to Manufacturing Technology (Overview of Manufacturing technologies)


1
Introduction to Manufacturing Technology
(Overview of Manufacturing technologies)
  • Instructors
  • (1)Shantanu Bhattacharya, ME, IITK, email
    bhattacs_at_iitk.ac.in
  • (2)Prof. Arvind Kumar, ME, IITK email
    arvindkr_at_iitk.ac.in

2
Overview of the Lecture
  • Manufacturing systems approaches.
  • Basic manufacturing processes. (Casting, Forming
    process, Fabrication process, Material removal
    process)
  • Advanced Machining processes (ECM, EDM, EBM, LBM,
    AJM, USM processes)
  • Micro-manufacturing processes (Etching,
    Deposition, Lithography, Replication and molding,
    Dip-pen lithography, Compression molding,
    Nano-imprint lithography)

3
Manufacturing Systems Approach
  • Definition of Manufacturing Technology
  • Manufacturing technology provides the tools that
    enable production of all manufactured goods. 
    These master tools of industry magnify the effort
    of individual workers and give an industrial
    nation the power to turn raw materials into the
    affordable, quality goods essential to todays
    society. 
  • Thus manufacturing process really represents
    adding value to a raw material and creation of
    wealth.

Replenish
Sales fluctuations
Production rate, quality and delivery
Manufacturing System comprising of manufacturing
processes
Raw materials cost and availability
Manufacturing Facility Add Value
Profit
Business environment
Input
Output
Social Pressure
Reputation
Resources and plans
Wealth
Manufacturing Process is the key to wealth
generation
4
Casting Processes
  • These are the only processes where liquid metal
    in used.
  • Casting is the oldest known manufacturing
    process.
  • It requires preparation of a cavity usually in a
    refractory material to resemble closely to the
    object to be realized.
  • Molten metal is poured into this refractory mould
    cavity and is allowed to solidify.
  • The object after solidification is removed from
    the mould.

5
Equilibrium Phase Diagrams
  • A convenient way of describing the phase
    transformations is a diagram where the phases at
    different combinations of temperatures and
    compositions are indicated.
  • Such a diagram is called an equilibrium phase
    diagram. The word equilibrium is indicative of
    the fact that at every temperature sufficient
    time is provided at every temperature to complete
    all diffusion processes.
  • The diagram in the left shows a phase diagram of
    Ni-Cu alloy which forms a solid solution without
    any restriction on composition.
  • The diagram has been obtained by study of the
    cooling curves for various composition of the
    alloys.

6
Forming Processes
  • These are solid state manufacturing processes
    involving minimum amount of material wastage and
    faster production.
  • Metal is heated to a temperature which is
    slightly below the solidus temperature and then a
    large force is applied such that the material
    flows and take the desired shape.
  • The desired shape is controlled by means of
    certain tools called dies which may be completely
    or partially closed during manufacture.
  • These processes are normally used for large scale
    production rates.

Extrusion
Drop forging
Rolling Process
Wire Drawing
7
Fabrication processes
  • These are secondary manufacturing processes
    where the starting raw materials are processed by
    any of the previous methods.
  • It essentially involves joining pieces either
    temporarily or permanently so that they would
    perform the necessary function.
  • The joining can be achieved by both heat and
    pressure and / or a joining material.

Gas Welding
Resistance Welding
Arc Welding
8
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9
Material Removal Processes
  • These are also secondary manufacturing processes
    where the additional unwanted material is removed
    in the form of chips from the blank material by a
    harder tool so that a final desired shape can be
    obtained.
  • Material removal is the most expensive
    manufacturing process because more energy is
    consumed, and also a lot of waste material is
    generated in the process.

Turning
Shaping
Grinding
Drilling
Milling
Sawing
10
History of Machining
  • Mankind used bones, sticks and stones as hand
    tools since the earliest times

The most ancient Paleolithic stone tool industry
the Oldowan was developed by the earliest members
of the genus Homo such as Homo habilis around
2.6 million years ago. and contained tools such
as choppers, burins and awls.
During the Upper Paleolithic further
technological advances were made such as the
invention of Nets, bolas, the spear thrower the
bow and arrow.
11
History of Machining
Hand held tools from Bronze Age developed around
1 million years back. Upto almost the
seventeenth century all tools were either hand
operated or done so by other very elementary
methods. Introduction of water, steam and later
electricity as useful sources of energy led to
the concept of power driven machine tools.
Ceremonial giant dirk of the Plougrescant-Ommersch
ans type, Plougrescant, France, 1500-1300BC.
Bronze Age weaponry and ornaments
John Wilkinson in 1774 first constructed a
precision machine for boring engine cylinders,
powered by steam.
12
History of Machining
  • 23 years later, Henry Maudslay made a further
    advancement in machining when he devised screw
    cutting engine lathes.
  • James Nasmyth invented the second basic machining
    tool for shaping and planing.

First Universal Milling machine was built by J.R.
Brown in 1862. In the late nineteenth century,
the grinding machine was introduced. An advanced
form of this process is the lapping process used
to produce a high quality surface finish and a
very tight tolerance
13
History of Machining
  • In the later part of 19th and 20th Centuries the
    machine tools became increasingly electrically
    powered.
  • The basic machine tools had further refinements
    for instance multiple point cutters for milling
    machines were introduced.
  • The whole machining paradigm was however still
    related to an operators judgment who by looking
    at a part and using his skills would set up an
    operation sequence and use this for machining the
    work piece. Accuracy of such a product would
    depend solely on the operator.
  • The introduction of NC (numerical control) in
    1953 lead to computer numeric control and direct
    numeric control.
  • Present capabilities of these tooling systems
    have enormously increased due to development in
    electronic controls and computers and present
    capabilities enable complex shapes to be produced
    with finishing accuracy close to a 1 Micron.

14
History of Machining
  • In modern machining practices, harder, stronger,
    and tougher materials that are more difficult to
    cut are used. So, processes should be independent
    of material properties of the work piece.
  • Non conventional machining practices came very
    handy as an alternative to the conventional
    domain which could handle shape complexity,
    surface integrity and miniaturization
    requirements.
  • Hybrid machining made use of the combined
    enhanced advantages of two or more participating
    processes.
  • Micromachining had emerged because of this
    change of capabilities.
  • Recent applications of micromachining include
    silicon/ glass micromachining, excimer lasers
    and photolithography.

15
History of Machining
  • Machines such as precision grinders may be
    capable of producing an accuracy level of 1
    microns that can be measured using laser
    instruments and optical fibers.
  • Future trends in micromachining include laser and
    electron beam lithography and super high
    precision grinding, lapping and polishing
    machines. For measurements high precision laser
    beam based scanners are used for measuring
    surface finish etc.
  • Nano-machining is a very recent trend in these
    processes wherein atoms and molecules can be
    removed instead of chips in conventional
    machines.
  • Nano-machining was introduced by Tanigushi to
    cover the miniaturization of components and
    tolerances in the range from submicron level to
    that of an individual atom or molecule between
    100nm and 0.1 nm.

16
Abrasive Machining Categories
  • The Metal abrasion action is adopted during
    grinding, honing and super finishing processes
    that employ either a solid grinding wheel or
    sticks in the form of bonded abrasive.
  • Furthermore in lapping, polishing, and buffing,
    loose abrasives are used as tools in a liquid
    medium.

17
Machining Accuracies
100 -1 microns
1 -0.01 microns
Micro-turning and Micro-Milling M/C
0.1 -0.001 microns
18
Classification of all Material Removal Processes
Area of interest
19
Non Traditional Machining
  • Traditional machining is mostly based on removal
    of materials using tools that are harder than the
    materials themselves.
  • New and novel materials because of their greatly
    improved chemical, mechanical and thermal
    properties are sometimes impossible to machine
    using traditional machining processes.
  • Traditional machining methods are often
    ineffective in machining hard materials like
    ceramics and composites or machining under very
    tight tolerances as in micromachined components.
  • New processes and methods play a considerable
    role in machining for aircraft manufacture,
    automobile industry, tool and die industry mold
    making etc.
  • They are classified under the domain of non
    traditional processes.

20
Classification of Non Traditional Machining
Single action non traditional Machining
processes For these processes only one
machining action is used for material removal.
These can be classified according to the source
of energy used to generate such a machining
action mechanical, thermal, chemical and
electrochemical.
21
Mechanical Machining
  • Ultrasonic Machining (USM) and Waterjet Machining
    (WJM) are typical examples of single action,
    mechanical non traditional machining processes.
  • The machining medium is solid grains suspended in
    an abrasive slurry in the former, while a fluid
    is employed in the WJM process.
  • The introduction of abrasives to the fluid jet
    enhances the machining efficiency and is known as
    abrasive water jet machining. Similar case
    happens when ice particles are introduced as in
    Ice Jet Machining.

22
Thermal Machining
  • Thermal machining removes the machining allowance
    by melting or vaporizing the work piece material.
  • Many secondary phenomena occur during machining
    such as microcracking, formation of heat affected
    zones, striations etc.
  • The source of heat could be plasma as during EDM
    and PBM or photons as during LBM, electrons in
    EBM, ions in IBM etc.

23
Chemical and Electrochemical Machining
  • Chemical milling and photochemical machining or
    photochemical blanking all use a chemical
    dissolution action to remove the machining
    allowance through ions in an etchant.
  • Electrochemical machining uses the
    electrochemical dissolution phase to remove the
    machining allowance using ion transfer in an
    electrolytic cell.

24
Introduction to Abrasive Jet Machining (AJM)
  • In AJM, the material removal takes place due to
    impingement of the fine abrasive particles.
  • The abrasive particles are typically of 0.025mm
    diameter and the air discharges at a pressure of
    several atmosphere.

25
Mechanics of AJM
  • Abrasive particle impinges on the work surface at
    a high velocity and this impact causes a tiny
    brittle fracture and the following air or gas
    carries away the dislodged small work piece
    particle.

26
Basics of the USM process
  • The basic USM process involves a tool ( made of a
    ductile and tough material) vibrating with a very
    high frequency and a continuous flow of an
    abrasive slurry in the small gap between the tool
    and the work piece.
  • The tool is gradually fed with a uniform force.
  • The impact of the hard abrasive grains fractures
    the hard and brittle work surface, resulting in
    the removal of the work material in the form of
    small wear particles.
  • The tool material being tough and ductile wears
    out at a much slower rate.

27
Electrochemical Machining (ECM)
  • Electrochemical machining is one of the most
    unconventional machining processes.
  • The process is actually the reverse of
    electroplating with some modifications.
  • It is based on the principle of electrolysis.
  • In a metal, electricity is conducted by free
    electrons but in a solution the conduction of
    electricity is achieved through the movement of
    ions.
  • Thus the flow of current through an electrolyte
    is always accompanied by the movement of matter.
  • In the ECM process the work-piece is connected to
    a positive electrode and the tool to the negative
    terminal for metal removal.
  • The figure below shows a suitable work-piece and
    a suitably shaped tool, the gap between the tool
    and the work being full of a suitable
    electrolyte.

28
Electrochemical Machining
  • With ECM the rate of metal removal is
    independent of the work-piece hardness.
  • ECM becomes advantageous when either the work
    material possesses a very low machinability or
    the shape to be machined is complex.
  • Unlike most other conventional and unconventional
    processes, here there is practically no tool
    wear.
  • Though it appears that, since machining is done
    electrochemically, the tool experiences no force,
    the fact is that the tool and work is subjected
    to large forces exerted by the high pressure
    fluid in the gap.

29
Electric Discharge Machining
  • EDM is the process of material removal by a
    controlled erosion through a series of electric
    sparks.
  • It was developed in USSR around 1943.
  • The basic process is illustrated below.
  • When a discharge takes place between two points
    of the anode and cathode the intense heat
    generated near the zone melts and evaporates the
    materials in the sparking zone.
  • For improving the effectiveness the work-piece
    and the tool are submerged in a dielectric fluid.
    (Mineral oils or hydrocarbons)
  • Experiments indicate that in case both electrodes
    are of the same material there is a prominently
    more erosion of the electrode connected to the
    positive terminal.

30
Schematic view of the e-beam machine
  • The figure below shows the basic schematic view
    of the electron beam machine.
  • The electrons are emitted from the cathode (a hot
    tungsten filament), the beam is shaped by the
    grid cup, and the electrons are accelerated due
    to a large potential difference between the
    cathode and the anode.
  • The beam is focussed with the help of the
    electromagnetic lenses.
  • The deflecting coils are used to control the beam
    movement in any required manner.
  • In case of drilling holes the hole diameter
    depends on the beam diameter and the energy
    density.
  • When the diameter of the required hole is larger
    than the beam diameter, the beam is deflected in
    a circular path with proper radius.
  • Most holes drilled with e-beam are characterized
    by a small crater on the beam incident side of
    the work.

31
Introduction to MEMS fabrication
  • NEMS/ MEMS silicon fabrication
  • Formation of structures that could be used to
    form sensors and actuators.
  • Processing of electrical or non electrical
    signals.
  • Conventional and new semiconductor manufacturing
    techniques are used.
  • Etching, Deposition, Photolithography, Oxidation,
    Epitaxy etc.
  • Deep RIE, Thick plating etc.
  • Bulk and surface micromachining.

32
Topics Covered
  • Non-traditional Machining processes. (detailed
    analysis based AJM, USM, ECM, EDM, LBM, PAM,
    MRAFF, EDD, ECD, MEMS processes, RP processes,
    rapid tooling techniques) 10-Lectures
  • Traditional Machining processes.(detailed
    analysis on turning, milling, drilling, shaping
    ad planning processes, orthogonal and oblique
    cutting).06-Lectures
  • Introduction to Metrology.(Limits, fits,
    tolerances, Automated inspection and CMM),
    01-Lecture

33
Course Requirements
  • (1) 35 of total grade on Mid Semester
  • (2) 35 of total grade on Final Examination
  • (3) 30 of total grade on Experiments.
  • (The rationale of the distribution of 30 is the
    following 5 will be on report making, 5 will
    be based on feedback of supervisorial support,
    20 will be done on the basis of a lab quiz that
    will be taken towards the end of the semester at
    a mutually convenient date.)
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