thread

1
Turning Boring

• General Manufacturing Processes Engr.-20.2710
• Instructor - Sam Chiappone

2
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.

3
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.

4
Process Calculations

• Rpm calculation
• RPM
• CS

5
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)

6
Turning Operations

• Turning operations performed on a lathe include
• Straight turning
• Taper turning
• End facing
• Shoulder facing

7
Turning Operations

• Facing
• Grooving
• Form turning
• Parting-off

8
Turning Operations

• Threading
• Knurling
• Drilling
• Reaming
• Milling-CNC turning centers

9
Lathe Components

• Bed
• foundation of the lathe
• Headstock
• Mounted on the ways
• Consists of the
• Hollow spindle
• Bearings
• Transmission gears

10
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

11
Lathe Components

• Carriage
• Along with the apronprovides 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.

12
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.

13
Machine Classification

• Size designation
• Swing - maximum diameter that can be rotated on
  the lathe
• 2xs distance from spindle center line to ways
• Maximum distance between centers

14
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 12x24 to 24x48 - can be larger

15
Types of Lathes

• CNC
• Computer controlled
• Wide variety of process capability
• multiple axis
• Indexing and contouring head
• On- line and off- line programming available

16
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

17
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.

18
Types of Lathes
1
2
3
19
Cutting Tools for Lathes

• External
• Right hand turning
• Left hand turning
• Round nose turning
• Cut-off
• Left hand facing

20
Cutting tools for Lathes

• External (cont)
• Broad nose finishing
• Right hand facing
• Threading
• Form
• Internal
• Boring
• Threading
• Grooving
• Form

21
Workholding on a Lathe

• Between centers
• Live-tailstock
• Dead-headstock
• Face plate
• Drive dog

22
Workholding on a Lathe

• Chuck
• 3,4, or 6 jaw
• Soft jaws

23
Workholding on a Lathe

• Collect system

24
Workholding on a Lathe

• Others
• Face driver system
• Sub-spindle system