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					            Turning & Boring



General Manufacturing Processes Engr.-20.2710
         Instructor - Sam Chiappone
              Turning & Boring
   Turning is the process of machining external
    cylindrical and conical surfaces. The process uses
    a machine tool called a lathe. Boring is the
    process of enlarging an existing hole or internal
    cylindrical surface. This can be accomplished on
    a lathe or a machine tool specifically designed for
    the process; such as a horizontal boring machine.



                                                  GMP-20.271
               Rensselaer Polytechnic Institute    Chiappone
                Turning & Boring
   Some of the main reasons for utilizing this process
    include:
    –   Concentricity between features
    –   External thread to shaft diameter
    –   Part tolerance
    –   Surface finish
    –   Part features
   Turning typically involves roughing procedures
    followed by a finishing operation.
                                                     GMP-20.271
                  Rensselaer Polytechnic Institute    Chiappone
            Process Calculations
   Rpm calculation
    – RPM
    – CS




                                                 GMP-20.271
              Rensselaer Polytechnic Institute    Chiappone
             Process Calculations
   Feed is typically a given distance per revolution.
    This value is dependent on the operation, depth of
    cut, cutting speed, tool material, surface finish----
    etc. Units are--- in. per rev (in./rev)




                                                    GMP-20.271
                 Rensselaer Polytechnic Institute    Chiappone
               Turning Operations
   Turning operations performed on a lathe include:
    –   Straight turning
    –   Taper turning
    –   End facing
    –   Shoulder facing




                                                     GMP-20.271
                  Rensselaer Polytechnic Institute    Chiappone
          Turning Operations
–   Facing
–   Grooving
–   Form turning
–   Parting-off




                                                GMP-20.271
             Rensselaer Polytechnic Institute    Chiappone
           Turning Operations
–   Threading
–   Knurling
–   Drilling
–   Reaming
–   Milling-CNC
    turning centers




                                                 GMP-20.271
              Rensselaer Polytechnic Institute    Chiappone
                Lathe Components
   Bed
    – foundation of the lathe
   Headstock
    – Mounted on the ways
    – Consists of the:
          » Hollow spindle
          » Bearings
          » Transmission gears



                                                      GMP-20.271
                   Rensselaer Polytechnic Institute    Chiappone
                Lathe Components
   Spindle
    – Carries the workholders
    – Hole to accept long work or bar
      stock
   Tailstock
    – Lower portion of casting fits inner
      ways
    – Can slide longitudinally
       » Locks at desired location
       » Tailstock quill
                                                     GMP-20.271
                  Rensselaer Polytechnic Institute    Chiappone
               Lathe Components
   Carriage
    – Along with the apron—provides the base for mounting
      and moving cutting tools
   Cross slide
    – Mounted to the carriage and provides movement for
      facing and cut-off operations.
   Compound rest
    – Mounted to the cross slide. Can rotate for angle cuts.
      This is the component that holds the tool post for
      cutting tools.
                                                       GMP-20.271
                  Rensselaer Polytechnic Institute      Chiappone
               Lathe Components
   Feed rod
    – Provides forward and reverse motion for carriage and
      cross slide.
   Lead screw
    – Used for threading purposes. Engages with the half-nut
      to provide correct feed specific lead of thread.




                                                     GMP-20.271
                 Rensselaer Polytechnic Institute     Chiappone
         Machine Classification
   Size designation
    – Swing - maximum diameter that can be rotated on the
      lathe
       » 2x’s distance from spindle center line to ways
   Maximum distance between centers




                                                          GMP-20.271
                 Rensselaer Polytechnic Institute          Chiappone
                 Types of Lathes
   Speed
    – Simple construction of a head stock and tail stock with
      a tool post. Used for wood turning, metal polishing, or
      metal spinning.
   Engine
    –   Most frequently used lathe
    –   Heavy duty
    –   power drive for most tool movements
    –   Size range 12”x24” to 24”x48” - can be larger
                                                        GMP-20.271
                 Rensselaer Polytechnic Institute        Chiappone
                  Types of Lathes
   CNC
    –   Computer controlled
    –   Wide variety of process capability
    –   multiple axis
    –   Indexing and contouring head
    –   On- line and off- line programming available




                                                       GMP-20.271
                 Rensselaer Polytechnic Institute       Chiappone
                  Types of Lathes
   Toolroom
    – Greater accuracy
    – More versatility
    – Wider range of speeds and feeds
   Turret
    –   Hex turret replaces tailstock
    –   Multiple tools set to machine part
    –   High production rates
    –   Still may require some operator skill
                                                     GMP-20.271
                  Rensselaer Polytechnic Institute    Chiappone
                  Types of Lathes
   Automatic
    –   Similar to turret
    –   Eliminate operator control of machine
    –   Capable of simultaneous cuts
    –   Can be a cam controlled mechanism
    –   Can be single spindle or multiple spindle
   Tracer
    – Hydraulic attachment used to copy the shape of a part
      from a master.
                                                     GMP-20.271
                  Rensselaer Polytechnic Institute    Chiappone
    Types of Lathes




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                                           GMP-20.271
    Rensselaer Polytechnic Institute        Chiappone
          Cutting Tools for Lathes
   External
    –   Right hand turning
    –   Left hand turning
    –   Round nose turning
    –   Cut-off
    –   Left hand facing




                                                    GMP-20.271
                 Rensselaer Polytechnic Institute    Chiappone
           Cutting tools for Lathes
   External (con’t)
    –   Broad nose finishing
    –   Right hand facing
    –   Threading
    –   Form
   Internal
    –   Boring
    –   Threading
    –   Grooving
    –   Form
                                                    GMP-20.271
                 Rensselaer Polytechnic Institute    Chiappone
          Workholding on a Lathe
   Between centers
    –   Live-tailstock
    –   Dead-headstock
    –   Face plate
    –   Drive dog




                                                   GMP-20.271
                Rensselaer Polytechnic Institute    Chiappone
        Workholding on a Lathe
   Chuck
    – 3,4, or 6 jaw
    – Soft jaws




                                                   GMP-20.271
                Rensselaer Polytechnic Institute    Chiappone
        Workholding on a Lathe
   Collect system




                                                 GMP-20.271
              Rensselaer Polytechnic Institute    Chiappone
        Workholding on a Lathe
   Others
    – Face driver system
    – Sub-spindle system




                                                  GMP-20.271
               Rensselaer Polytechnic Institute    Chiappone

				
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posted:2/28/2012
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