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

What is the primary purpose of machining in metalworking processes?

  • To create irregular surfaces on workpieces
  • To shape metal components without removing excess material
  • To produce components with the desired dimensions and surface finish (correct)
  • To increase the hardness of the metal components

    • Which category of metalworking processes involves turning and milling?

  • Chip forming processes (correct)
  • Non-cutting shaping processes
  • Forging and pressing
  • Grinding and rolling

    • What is the essential role of cutting tools in machining?

  • Moving chips away from the work surface
  • Reducing friction between the tool and workpiece
  • Holding the workpiece in place during cutting
  • Removing excess material by gradual cutting action (correct)

    • Why do engineering components like gears and bearings require machining?

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

    What distinguishes machining from preforming processes like casting or forging?

    <p>Machining removes excess material gradually for accuracy and finish</p> Signup and view all the answers

    In metalworking, what type of components usually require semi-finishing and finishing after preforming?

    <p>Components like gears and bearings that need accuracy and finish</p> Signup and view all the answers

    What is the main role of rake angle in cutting tools?

    <p>To reduce cutting force and power requirement</p> Signup and view all the answers

    Which type of cutting tool has more than two major cutting edges involved?

    <p>Milling cutters</p> Signup and view all the answers

    In the Machine Reference System, what does ASA stand for?

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

    What is the purpose of clearance angle in cutting tools?

    <p>To avoid rubbing of the tool with the machined surface</p> Signup and view all the answers

    Which system of description of tool geometry identifies only the salient features of the cutting tool point without providing quantitative information?

    <p>Tool-in-Hand System</p> Signup and view all the answers

    What determines the choice of planes and axes used for expressing tool geometry in the ASA system?

    <p>Configuration and axes of the machine tool</p> Signup and view all the answers

    Why is clearance angle a must for cutting tools according to the text?

    <p>To avoid rubbing of the tool with the machined surface</p> Signup and view all the answers

    What is primarily referred to as tool geometry in cutting tools?

    <p>Angles or slopes of salient faces and edges at the cutting point</p> Signup and view all the answers

    'Two-point' cutting tools are exemplified by which type according to the text?

    <p>'Drills'</p> Signup and view all the answers

    What is the purpose of a machine tool in machining?

    <p>Produce geometrical surfaces on preformed blanks using cutting tools</p> Signup and view all the answers

    How does cutting fluid assist in the machining process?

    <p>It cools and lubricates during machining</p> Signup and view all the answers

    Which type of machine tool is suitable for mass production?

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

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

    <p>Provide power to the tool-work pair</p> Signup and view all the answers

    Which classification of machine tools is based on the number of spindles?

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

    Which type of machine tool is characterized by housing type blanks?

    <p>Housing type machine tools</p> Signup and view all the answers

    In machining, what do machine tools do physically?

    <p>Hold blanks and cutting tools firmly</p> Signup and view all the answers

    What aspect is used for specifying a centre lathe?

    <p>Maximum diameter and length of accommodated jobs</p> Signup and view all the answers

    Which condition favors the formation of continuous chips without BUE chips?

    <p>Feed - high</p> Signup and view all the answers

    What type of chips are formed when cutting brittle materials like cast iron?

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

    Which scenario is associated with higher power consumption?

    <p>Cutting brittle materials</p> Signup and view all the answers

    What is the role of a positive and large rake angle in chip formation?

    <p>Aids in continuous chip formation</p> Signup and view all the answers

    When is shearing of metal observed during the machining process?

    <p>When cutting ductile materials</p> Signup and view all the answers

    What is the primary function of cutting fluid in machining processes?

    <p>Cooling and lubricating the cutting tool</p> Signup and view all the answers

    What is the angle of chip flow deviation from the orthogonal plane in oblique cutting?

    <p>45 degrees</p> Signup and view all the answers

    In pure orthogonal cutting, what is the angle between the chip flow and the reference plane?

    <p>90 degrees</p> Signup and view all the answers

    What is the main purpose of machining according to the text?

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

    What is the major index that the form of machined chips indicates?

    <p>Work material behavior under machining conditions</p> Signup and view all the answers

    What mainly influences the form of machined chips?

    <p>Cutting tool geometry and cutting velocity</p> Signup and view all the answers

    What happens when the shear stress in the work material exceeds its shear strength?

    <p>Yielding or slip takes place resulting in shear deformation</p> Signup and view all the answers

    In what direction does shear stress develop in the region ahead of the cutting tool during continuous machining?

    <p>In different magnitude and directions</p> Signup and view all the answers

    What causes the formation and removal of chips in thin layers during machining?

    <p>Compression followed by yielding and shear repeatedly</p> Signup and view all the answers

    How does the lower surface of actual machining chips appear?

    <p>Serrated due to intensive rubbing</p> Signup and view all the answers

    According to Piispannen's explanation using a card analogy, what does the phenomenon shown in Fig. 1.11 (b) represent?

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

    What is the definition of the shank of a single point tool in the ASA system?

    <p>The portion of the tool bit which is not ground to form cutting edges and is rectangular in cross section</p> Signup and view all the answers

    Which angle in the ASA system represents the angle of inclination of the principal flank from the machined surface and is measured on the machine longitudinal plane?

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

    In the ASA system, what does the nose radius of a single point tool provide?

    <p>Strengthens the tool nose and improves surface finish</p> Signup and view all the answers

    Which type of metal cutting process involves the cutting edge or face of the tool being inclined at an angle less than 90 degrees to the line of action?

    <p>Oblique cutting process</p> Signup and view all the answers

    What makes the analysis simpler in orthogonal cutting process?

    <p>Only involves two forces</p> Signup and view all the answers

    What does the x angle represent in ASA system's tool geometry designation?

    <p>Side rake angle (axial rake)</p> Signup and view all the answers

    In ASA system, what does ay represent in tool geometry designation?

    <p>End relief angle</p> Signup and view all the answers

    What are the factors that the pattern and extent of total deformation of the chips depends upon in machining?

    <p>Work material, tool material, and machining speed</p> Signup and view all the answers

    In the context of chip formation, which experimental method involves studying running chips using a high-speed camera with a low magnification microscope?

    <p>Study of running chips by a high-speed camera</p> Signup and view all the answers

    In machining, what prevents the propagation of a crack at the tool tip in ductile materials?

    <p>Yielding at the crack-tip</p> Signup and view all the answers

    Which type of materials generally undergo yielding rather than brittle fracture during machining?

    <p>Ductile materials</p> Signup and view all the answers

    What is the main reason behind why chip thickness (a2) becomes larger than uncut chip thickness (a1) during machining?

    <p>Compression of the chip ahead of the tool</p> Signup and view all the answers

    What are the main mechanisms involved in chip formation when machining brittle materials?

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

    What type of chips are generally produced when machining ductile materials?

    <p>Flat, curved, or continuous chips</p> Signup and view all the answers

    What is the major factor that determines the pattern and degree of deformation during chip formation in machining processes?

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

    Which experimental method involves studying deformation of rectangular or circular grids marked on the side surface?

    <p>Deformation of grids marked on side surface</p> Signup and view all the answers

    What is the possible reason for chip thickness (a2) exceeding uncut chip thickness (a1) during machining?

    <p>Frictional resistance to chip flow</p> Signup and view all the answers

    How is chip thickening commonly expressed?

    <p>rc = a2 / a1 * 1.00</p> Signup and view all the answers

    What does a larger value of rc indicate?

    <p>More thickening</p> Signup and view all the answers

    How is chip thickening also expressed?

    <p>rc = a1 / a2</p> Signup and view all the answers

    How can the value of rc be reduced according to the text?

    <p>Using tool with larger positive rake and reducing friction by using lubricant</p> Signup and view all the answers

    What does equation 1.5 in the text represent?

    <p>Chip volume conservation</p> Signup and view all the answers

    What does shear angle depend on?

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

    How does shear angle change with the increase in chip reduction coefficient?

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

    What is cutting strain defined as in the text?

    <p>'Shear' magnitude along the shear plane due to machining action</p> Signup and view all the answers

    'Total volume of chip produced in a given time' conservation is represented by which equation in the text?

    <p>(a1b1)VC = (a2b2)Vf</p> Signup and view all the answers

    What is the formula for cutting strain (average) as mentioned in the text?

    <p>e = PM / ON</p> Signup and view all the answers

    What factor(s) can encourage and accelerate the bonding of Built-up-Edges (BUE) as discussed in the text?

    <p>High stress and temperature with mutual affinity of chip-tool materials</p> Signup and view all the answers

    In machining soft and ductile metals with tools like high speed steel, where can Built-up-Edges (BUE) grow larger and overflow towards as per the text?

    <p>Towards the finished surface through the flank</p> Signup and view all the answers

    Under what condition may Built-up-Edges (BUE) be squashed out by the flowing chip according to the text?

    <p>When cutting velocity (VC) is raised too high</p> Signup and view all the answers

    What harmful effect can Built-up-Edges (BUE) formation have on surface finish according to the content?

    <p>Deteriorates surface finish</p> Signup and view all the answers

    What effect does repeated formation and dislodgement of Built-up-Edges (BUE) have on cutting forces according to the text?

    <p>Induces vibrations</p> Signup and view all the answers

    Which factor influences the type of chips produced by machining as mentioned in the text?

    <p>Levels of cutting velocity and feed</p> Signup and view all the answers

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