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    TERM PAPER

    TOPIC- CUTTING TOOL TECHNOLOGY

    SUMITTED TO SUMITTED BY:

    MS. SANDHYA SINGH RAKSHIT SAHU

    ROLL NO.-RK4006A03REG.NO.-11006227

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    (ACKNOWLEDGEMENT)

    If practical knowledge carves and sharps the carrier of a person, practical experience polishes

    it and adds luster and brilliance to it. Here, we found this golden chance to acknowledge all

    those people who had blessed, encouraged and supported us technically and morally throughall the phases of our term paper. We take this opportunity to express our profound sense of

    gratitude. We thank all mighty God for giving us this valuable opportunity to express to all

    those who helped in successful completion of this term paper.

    Before we get into thick of the things I would like to add a few heartfelt words for the

    people who were part of this term paper in numerous ways. We reserve heartiest gratitude to

    who has been very supportive and encouraging throughout this term paper. He guides us for

    having given us an opportunity to undertake the term paper and providing us with feedback

    and influenced the development of this term paper. We gratefully acknowledge invaluable

    note of our term paper guide MS. SANDHYA SINGH and to all teachers who besides

    helping us in this term paper, guided and encouraged us along each step.

    We express heartfelt thanks to our friends for their morale and support and kind

    corporation during this course of formulation of this project work who directly or indirectly

    helps us to complete this term paper. Last but not least, my sincere regards are reserved for

    our family and friends who have always encouraged and blessed us with their best. Specially

    thanks to my elder brothers who always encourage me to do your best.

    RAKSHIT SAHU

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    CONTENTS:

    Introduction

    Cutting tool technology

    Tool life

    Taylor tool life equation

    Tool material

    Types of tool materials

    Tool geometry

    Cutting tools

    Latest technology

    Safety

    Future scope

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    CUTTING TOOL TECHNOLOGY

    1. Tool life

    2. Tool Materials3. Tool Geometry

    4. Cutting fluids

    1. Tool life

    Three modes of failure

    o Premature Failure

    o Fracture failure -Cutting force becomes excessive and/or dynamic, leading to

    brittle fracture

    o Thermal failure -Cutting temperature is too high for the tool material

    Gradual

    o Wear Gradual failure

    Tool wear: Gradual failure

    o Flank wear -flank (side of tool)

    o Crater wear -top rake face

    o Notch wear

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    o Nose radius wear

    Crater and Flank Wear

    Selection of cutting tool materials is very important

    What properties should cutting tools have

    Hardness at elevated temperatures

    Toughness so that impact forces on the tool can be taken

    Wear resistance

    Chemical stability

    Types of tool materials

    o Carbon + medium alloy steel

    o High speed steel (HSS)

    o Cast cobalt alloys

    o Carbides

    o Coated tools

    o Ceramics

    o Cubic boron nitride

    o invented by GE in 1969

    o Silicon nitride

    o Diamond

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    CUTTING TOOL TECHNOLOGY

    Three possible failure modes of cutting tool

    Fracture failure: due to excessive force, failed suddenly in a brittle pattern

    Temperature failure: due to high temperature at tool tip, failed gradually in a ductile

    pattern

    Gradual wear: most commonly seen, similar to temperature effect

    Gradual wear occurs at two principal locations: crater wear and flank wear

    Crater wear: formed a concave section on the rake face of the tool due to the sliding of the

    chips

    Flank wear: formed a rough surface on the flank face due to the constant abrasion

    between newly created work surface and flank face

    WHAT IS TOOL LIFE?

    It is defined as the length of cutting time that the tool is performing satisfactorily.

    Tool life is a function of time, and the wear-out curve is similar to a creep test curve.

    For flank wear: quantitative analysis and qualitative analysis.

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    TAYLOR TOOL LIFE EQUATION (QUANTITATIVE)

    Developed in 1900 by F. W. Taylor

    vTn = C

    Where v = cutting speed, ft/min

    T = tool life, min

    n depends on tool material

    C depends on workpiece and cutting conditions

    A modified tool life equation: vTn = C (Tnref)

    = Where Tnref is a reference value for C (1 minute)

    In the tool life prediction, one needs to know n and C first.

    The entire equation becomes vTconstant = constant [once v is known, then T can becalculated]

    Tool life prediction (qualitative analyses): complete failure of cutting edge, visual

    inspection of flank face, fingernail test across cutting edge by operator, change in sound

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    emitting during cutting, chip shape change, increased power consumption, longer cutting

    time, etc.

    TOOL MATERIALS

    Three important properties for tool materials

    toughness

    Hot hardness (Rc > 60)

    Wear resistance (including chemical reaction)

    Surface treatment on plain carbon steels: hydrogen embrittlement, nitrogen embrittlement,

    and carburization

    TYPES OF TOOL MATERIAL

    o High-speed steels (HSS): highly alloyed tool steel capable of maintaining

    hardness at elevated temperatures.

    o two types of HSS: T-grades (12 20% tungsten) and M-grades (6% tungsten and 5%

    molybdenum)

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    o Cemented carbides: hard tool materials manufactured through powder metallurgy

    methods, consists of tungsten carbide (WC) and cobalt (Co), titanium carbide (TiC) and

    Co, or tantalum carbide (TaC) and Co.

    o Cermets: combinations of titanium carbide (TiC) and titanium nitride (TiN) with

    nickel and/or molybdenum as binders.

    o Coated carbides: cemented carbides coated with thin layers of wear-resistant material

    such as titanium carbide, titanium nitride, and/or aluminum oxide. (including chromium

    carbide, zirconium nitride, and diamond)

    TOOL GEOMETRY

    Single-point tool: end relief angle, side relief angle, side cutting edge angle, nose radius,

    end cutting edge angle

    Chip breakers: force chip to curl and fracture

    Effects of tool material on geometry

    Cutting fluids two types: coolants (water base) and lubricants (oil base with S, Cl, P)

    Coolants are used for high cutting speeds and heat generation

    Lubricants are used for low cutting speeds with high pressure

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    Three categories of cutting fluids: cutting oils, emulsified oils, chemical and semi-

    chemical fluids

    Cutting oils are generated from petroleum , animal, marine, and vegetable origin.

    Emulsified oils are mixtures of mineral oil and water (suspension)

    Chemical fluids are chemicals in water solution.

    CUTTING TOOLS

    The proper holder maintained under all of the correct standards is still only as good as the

    cutting tool it contains. A quality tool is determined by three primary factors:

    1. Materials (substrates)

    2. Geometry

    3. Coatings

    MATERIALSThe best designs and coatings in the world are of little value if they are not applied to the

    appropriate substrates. Using an end mill with a subpar substrate is like using a front door

    made from cardboard on a new house. From a distance it looks the same, but a closer look

    will reveal the obvious flaws that make it unsuitable for its intended purpose.

    Carbide Grain Classification Grain Size [microns]

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    Fine Micro-grain Carbide 1.0 ~ 1.3

    extra-fine Micro-grain Carbide 0.5 ~ 0.9

    Ultra-fine Micro-grain Carbide 0.3 ~ 0.5

    Nano-series Micro-grain Carbide 0.1 ~ 0.3

    CUTTING TOOL (MACHINING)

    A "numerical controlled machining cell machinist" monitors a B-1B aircraft part being

    manufactured.

    A cutting tool has one or more sharp cutting edges and is made of a material that is harder

    than the work material. The cutting edge serves to separate chip from the parent work

    material. Connected to the cutting edge are the two surfaces of the tool

    The rake face; andThe flank.

    The rake face which directs the flow of newly formed chip, is oriented at a certain angle is

    called the rake angle "". It is measured relative to the plane perpendicular to the work

    surface. The rake angle can be positive or negative. The flank of the tool provides a clearance

    between the tool and the newly formed work surface, thus protecting the surface from

    abrasion, which would degrade the finish. This angle between the work surface and the flank

    surface is called the relief angle. There are two basic types of cutting tools Single point tool; and

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    Multiple-cutting-edge tool.