Theory of Metal Cutting: Introduction and Material Removal Processes
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Questions and Answers

What is the purpose of machining as explained in the text?

  • To create metal components with irregular shapes
  • To apply heat treatment to the metal components
  • To remove excess material and achieve desired dimensions and surface finish (correct)
  • To increase the weight of the metal components

    • Which classification of metal working processes involves turning, drilling, and milling?

  • Cutting shaping or metal cutting process (correct)
  • Forging process
  • Metal forming process
  • Non-cutting shaping or chips less process

    • How are engineering components like gears and bearings typically finished for accuracy and good surface finish?

  • Through casting and forging
  • By machining and grinding (correct)
  • By preforming blanks
  • By applying heat treatment

    • What is the key function of cutting tools in the machining process?

    <p>To gradually remove excess material from the workpiece</p> Signup and view all the answers

    Why do preformed parts called blanks need semi-finishing and finishing according to the text?

    <p>To provide dimensional accuracy and good surface finish</p> Signup and view all the answers

    What distinguishes metal cutting or chip forming processes like turning from non-cutting shaping processes like forging?

    <p>The formation of chips during metal cutting processes</p> Signup and view all the answers

    What type of cutting tools involve more than two major cutting edges?

    <p>Multipoint tools</p> Signup and view all the answers

    What is the main purpose of providing a positive rake angle in cutting tools?

    <p>Simplify design and manufacture</p> Signup and view all the answers

    In metal cutting operations, what does the clearance angle help to avoid?

    <p>Rubbing of the tool with the machined surface</p> Signup and view all the answers

    Which system of tool description involves providing quantitative information about the angles?

    <p>Machine Reference System</p> Signup and view all the answers

    What does the term 'ORS' stand for in tool geometry?

    <p>Orthogonal Rake System</p> Signup and view all the answers

    Which type of cutting tool has a positive clearance angle between 30 and 150 degrees?

    <p>Turning tools</p> Signup and view all the answers

    What role does the rake angle play in metal cutting?

    <p>Help with chip flow</p> Signup and view all the answers

    'ASA' system in tool geometry stands for which of the following?

    <p>American Standards Association</p> Signup and view all the answers

    'WRS' is associated with which system of describing tool geometry?

    <p>&quot;Work&quot; Reference System</p> Signup and view all the answers

    'NRS' is a part of which system of tool description?

    <p>&quot;Normal&quot; Rake System</p> Signup and view all the answers

    What is the main function of a machine tool in machining?

    <p>Firmly hold the blank and the cutting tool</p> Signup and view all the answers

    How are machine tools broadly classified based on size?

    <p>Based on duty (heavy, medium, small, micro)</p> Signup and view all the answers

    What is the purpose of a cutting fluid in machining?

    <p>To ease machining by cooling and lubrication</p> Signup and view all the answers

    Which type of machine tool is used for mass production?

    <p>Special purpose machine tool</p> Signup and view all the answers

    What is the classification of machine tools according to automation levels?

    <p>Based on degree of automation (non-automatic, semi-automatic, automatic)</p> Signup and view all the answers

    Which type of machine tool is typically used for heavy-duty tasks like boring mills?

    <p>Heavy duty machine tool</p> Signup and view all the answers

    What are the basic functions of a machine tool in machining?

    <p><em>Firmly</em> hold the blank and the tool, transmit motions, provide power, control parameters</p> Signup and view all the answers

    'Ordinary' and 'high precision' are classifications under which category related to machine tools?

    <p>'According to precision'</p> Signup and view all the answers

    'Single spindle' and 'multi spindle' are classifications under which category related to machine tools?

    <p>'According to number of spindles'</p> Signup and view all the answers

    Which type of automation is associated with CNC milling machines?

    <p>'Flexible automation'</p> Signup and view all the answers

    What is meant by chip flow deviation angle in machining?

    <p>The angle between the chip flow and the orthogonal plane</p> Signup and view all the answers

    In pure orthogonal cutting, what are the values of the angles a and f?

    <p>a = 0°, f = 90°</p> Signup and view all the answers

    What is the main index of machining that is indicated directly or indirectly by the form of machined chips?

    <p>Specific energy requirement</p> Signup and view all the answers

    What mainly determines the form of machined chips?

    <p>Work material</p> Signup and view all the answers

    In machining ductile materials, what happens when shear stress exceeds the shear strength of the work material in the deformation region?

    <p>Shear deformation occurs</p> Signup and view all the answers

    What is responsible for causing shear stresses in the region of the chip during machining ductile materials?

    <p>Both normal force and frictional force</p> Signup and view all the answers

    How does slip or shear propagation stop during chip formation in machining ductile materials?

    <p>Forces causing shear stresses diminish and disappear</p> Signup and view all the answers

    What does the Piispannen model of card analogy aim to explain in machining ductile materials?

    <p>Chip formation by shear in lamella</p> Signup and view all the answers

    What characteristic of chips helps understand nature and behavior of work material under machining conditions?

    <p>Chip form</p> Signup and view all the answers

    What mainly determines the nature and degree of interactions at the chip-tool interfaces?

    <p>Work material properties</p> Signup and view all the answers

    What is the surface against which the chip slides upward on a single point tool?

    <p>Face</p> Signup and view all the answers

    In the ASA system, what is the angle of inclination of the principal flank from the machined surface and measured on the machine's longitudinal plane (X plane)?

    <p>Side clearance angle</p> Signup and view all the answers

    Which angle provides strengthening of the tool nose and better surface finish?

    <p>Nose radius</p> Signup and view all the answers

    In metal cutting processes, what is characteristic of orthogonal cutting?

    <p>Tool face is at 90 degrees to the line of action or cutting velocity vector</p> Signup and view all the answers

    What is the role of an inclination angle in the direction of chip flow according to Fig. 1.8?

    <p>Chip flows along orthogonal plane when inclination angle is 0 degrees</p> Signup and view all the answers

    Which plane in metal cutting contains the principal cutting edge?

    <p>Reference plane (R)</p> Signup and view all the answers

    What does the auxiliary flank in a single point cutting tool refer to?

    <p>&quot;The additional flank surface besides the principal flank&quot;</p> Signup and view all the answers

    "Face" on a single point tool is defined as:

    <p>&quot;The surface against which the chip slides upward&quot;</p> Signup and view all the answers

    "Base" of a single point tool refers to:

    <p>&quot;The underside of the shank&quot;</p> Signup and view all the answers

    In ASA system, what is ax related to?

    <p>Side clearance angle (Side relief angle)</p> Signup and view all the answers

    What material property favors the formation of discontinuous chips?

    <p>Brittle</p> Signup and view all the answers

    What are the two basic mechanisms involved in chip formation during machining?

    <p>Yielding and brittle fracture</p> Signup and view all the answers

    How is the final deformation primarily accomplished in machining ductile materials?

    <p>Shear</p> Signup and view all the answers

    Which type of chip formation process consumes lesser power and results in metal being fractured into segments?

    <p>Segmental chips</p> Signup and view all the answers

    What factor contributes to the formation of continuous chips without Built-Up Edge (BUE) chips?

    <p>Positive rake angle</p> Signup and view all the answers

    What is the major reason that chip thickness (a2) becomes larger than the uncut chip thickness (a1) in machining?

    <p>Lamellar sliding effect</p> Signup and view all the answers

    Which method is NOT suggested as a feasible experimental method to study the deformation of machining chips?

    <p>Exposing chips to extreme heat</p> Signup and view all the answers

    In metal cutting, what role does cutting fluid play in chip formation?

    <p>Cooling and lubrication</p> Signup and view all the answers

    What condition is favorable for producing continuous chips during metal cutting?

    <p>High cutting velocity and low feed rate</p> Signup and view all the answers

    Why does yielding occur at the crack-tip for ductile materials during machining?

    <p>To reduce the effect of stress concentration</p> Signup and view all the answers

    What causes total separation of chips from the parent workpiece in machining brittle materials?

    <p>Crack propagation</p> Signup and view all the answers

    Which type of chip formation is associated with shearing the metal and requires a positive and large rake angle?

    <p>Continuous chips</p> Signup and view all the answers

    What geometrical parameter represents the depth of cut during machining?

    <p>$t$</p> Signup and view all the answers

    In machining, what happens to the width of the chip after the cut compared to before the cut?

    <p>It increases</p> Signup and view all the answers

    'Chip reduction coefficient' or 'cutting ratio' is quantitatively assessed to understand which aspect of machining?

    <p>$Forces$ and $energy$ required</p> Signup and view all the answers

    What is the primary factor that determines the pattern and extent of total deformation in machining chips?

    <p>Work material properties</p> Signup and view all the answers

    What does a larger value of chip reduction coefficient, rc, indicate?

    <p>More effort in terms of forces or energy required</p> Signup and view all the answers

    How is chip thickening often expressed in relation to the reciprocal of rc?

    <p>By the ratio of total length of the chip before and after cut</p> Signup and view all the answers

    What plays a significant role in reducing the value of rc according to equation 1.4?

    <p>Increasing friction by using lubricant</p> Signup and view all the answers

    What is the shear angle dependent on?

    <p>Chip thickness after cut and before cut</p> Signup and view all the answers

    What does a decrease in shear angle indicate about machining conditions?

    <p>More favorable conditions requiring less specific energy</p> Signup and view all the answers

    How can cutting strain be defined in machining processes?

    <p>The deformation that occurs along the shear plane</p> Signup and view all the answers

    In equation 1.3, what does 'r' represent?

    <p>Cutting ratio</p> Signup and view all the answers

    According to equation 1.8, how does Vf compare to VC?

    <p>$V_f$ is less than $VC$</p> Signup and view all the answers

    'Shear angle increases both directly and indirectly with what factor?'

    <p>$f$ (principal cutting edge angle)</p> Signup and view all the answers

    What is the main cause of Built-up-Edge (BUE) formation in machining ductile metals?

    <p>Strong bonding due to adhesion between chip-tool materials</p> Signup and view all the answers

    How does the force, F, relate to the Built-up-Edge (BUE) formation?

    <p>Causes the BUE to break or shear off when it exceeds the bonding force</p> Signup and view all the answers

    What factor influences the shape, size, and bond strength of Built-up-Edges (BUE) formed during machining?

    <p>Cutting fluid application</p> Signup and view all the answers

    What harmful effect does the formation of Built-up-Edges (BUE) have on cutting forces and power consumption?

    <p>Leads to fluctuations in cutting forces</p> Signup and view all the answers

    In the context of machining, what does excessive cutting temperature due to high cutting velocity favor?

    <p>Accelerated BUE formation</p> Signup and view all the answers

    Why does the workpiece experience plastic deformation during machining to produce continuous chips?

    <p>To separate the metal along a ribbon-like path</p> Signup and view all the answers

    What role do cutting fluid type and application method play in determining chip types in machining?

    <p>Affecting chip color and size</p> Signup and view all the answers

    Under what condition do chips overflow towards the finished surface through the flank in machining soft and ductile metals?

    <p>'Uncoated carbide' tools are employed</p> Signup and view all the answers

    Why does excessively high cutting velocity lead to squashing out of Built-up-Edges (BUE) before they grow?

    <p>Exceeds the bonding force of the BUE causing it to break off</p> Signup and view all the answers

    What characteristic of chips gets deteriorated due to the presence of Built-up-Edges (BUE) during machining?

    <p>Surface finish quality</p> Signup and view all the answers

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